Project SIGN Progress Report, Air Materiel Command Initial Report, 1948
Prepared summary.
The Air Materiel Command issued this initial report on unidentified flying objects on 23 April 1948, prepared at Wright-Patterson Air Force Base under Project SIGN, which had been directed by a Headquarters USAF letter dated 30 December 1947 signed by General L. C. Craigie on the subject of "Flying Discs." The report tabulates 100 sightings from 1947 through 1 February 1948, noting that exhaust trails were reported 23 times and that speeds ranged from hovering to supersonic.
Source text
Document text
[page 1]
CONFIDENTIAL
HEADQUARTERS
AIR MATERI EL COMMAND
DECLASSIFIED
Authority:
NND 927545
MCIA/JCB/amb
Wright-Patterson Air Force Base
Dayton, Ohio
23 APR 1948
MCIA
SUBJECT: Project "SIGN"
TO: Chief of Staff
United States Air Force
Washington 25, D. C.
ATTN: Director of Intelligence
l. Thie ie an initial report on unidentified flying objecta aa direoted by Rq, USAY letter dated SO Deoember 1947, signed by General L. C. Craigie, subjeot1 •r1~Jng Diaea~. Qtarterly reports will be submitted beginning 1 July 1948.
2. As a result of this letter, Project HT-304 was activated on 26 January 1948 and Technical Instruction 2185, dated 11 February 1948, was published. Present files on Project "SIGN" represent a consolida- tion of reports received directly by Hq, AMC and those forwarded by the Director of Intelligence, USAF.
~. Schedules of activities of li ghted night-flying adTertising blimps have been secured a.nd crosa-oheoked at thi.a Headquarters to consider them as a possible souroe ot incident nporta.
4. Inoloaure l represents a tabulation am breakdoWll of all available reports through l February 1948.
[page 2]
AMC
Subject: Project "SIGN"
23 APR 1948
e. »umber of objects per aighting,
| Objects per sighting | l | 2-6 | 6-10 | over 10 |
|-|-|-|-|-|
| Number of eightioga | 77 | 21 | 8 | 9 |
t. Exhaust traile were reported 23 times.
g. Speed has been eetime.ted throughout the entire range from very alow or hovering to supersonio.
6. Inclosures 2 and 3 are enlargements of photographs taken of Incident #40. Inclosure 4 is an evaluation of inclos ure 2 by this Headquarters. Attention is invited to the marked similarity between inclosures 2 and 3, and inclosure 5. Similarity also exists between. inclosures 2 and 3 and configurations illustrated in inolosure 6.
[page 3]
/ •
# CONFIDENTIAL
-
# CONFIDENTIAL (cont.)
| Incident No. | Date | Hour | Location | 5 N<>•<br />Sighted | Obser,ed<br />P'rom |
|-|-|-|-|-|-|
| 1 | g Jul 47 | 0930 | Muroc ilT Field, M'uroc, C alif. | 2 | Gro und |
| la | g Jnl 47 | 0930 | Muroc,Air Field, Muroc, Cali£. | 2 | Ground |
| lb | e Jul 47 | 0930 | Muroc Air li ' ield, li&uroc, Cali.f. | 2 | Ground |
| le | g Jul 47 | 09tl9 | Muroc .lir Field, lluroc, Calif. | 2 | Ground |
| ld | g Jul 47 | 1000 | lmroc Air Field, Muroc, Calif. | 3 | Ground |
| le | g Jul 47 | 1000 | Uuroc A.Lr Field, itiuroc, Calif. | 3 | Ground |
| 2 | g Jnl 47 | 1200 | Muroc Air Field, Mu.roe, Call!. | 1 | Ground |
| ~ | 7 Jul 47 | 1010 | Iifuroc Air Field, Vuroc, Calif. | 1 | Ground |
| 4 | $ Jul 47 | 1150 | Air Area Field 113, Rogers , Muroc, Dry Calif. Lake, Muroc | l | Ground |
| 5 | 4 Jul 47 | 1305 | ~ortland, Oregon | 5 | Ground |
| 6 | 4 Jul 47 | 1305 | 1llli.lwaukee, Oregon | 3 | Grotmd |
| 7 | 4 Jlll . 47 | 1305 | Portland, Oregon | 1 | Ground |
| ~ | 4 Jul 47 | 1305 | Portland, Uregon | 3 | Ground |
| 9 | 4 Jul 47 | 1305 | Portland, Oregon | undetermined wt atated | undetermined wt atated |
| 10 | 4 Jul 47 | 2004 | Roi se, Idaho | 5 | Air |
| ll | 4 Jul 47 | not stated | Seattle , X ashin g ton | l | r .:. round |
| 12 | 4 Jul 47 | 1305 | Vancouver, Washington | 20-30 | Ground |
| 1~ | 4 Jul 47 | 1400 | Portland, Oregon | 4 | Ground |
| 14 | 4 Jul 47 | 16}0 | Portland, Oregon | 1 | Ground |
| 15 | 4 Jul 47 | 1700 | Po rtland, Oregon | 3 | Ground |
| l.6 | 4 Jul 47 | ll.00 | Mount R edmon, Jefferson Oregon near | 4 | Ground |
| 17 | 2ll. Jun 47 | 1500 | 14t. Rainier, a.shington | 9 | 11r |
| l!S | not stated | not stated Toronto, Canada | not stated Toronto, Canada | 1 | Ground |
| 19 | 20 Oot 47 | 1320 | Dayton, Ohio | 2 | Ground |
| 20 | 20 Oct 47 | 1100 | Xenia, Onio • | l 1 | Ground |
# CONFIDENTIAL
| Incident<br />No. | Date | dour | Location | No.<br />Sighted | | Observed From |
|-|-|-|-|-|-|-|
| 21 | 29 Jun 47 | 1645 | Des Moines, 1owa | l~ | | not stated |
| 22 | 21 Jwi 47 | about noon | Spokane, · 1ashingt,on | several | | Ground |
| 23 | 30 Jun 47 | 1745 | B oise, Idaho | 1 | | Ground |
| 24 | 12 J\111 47 | 1&5 | W eiser, Idaho | 2 | | Ground |
| 25 | 4 Jul 47 | 2345 | Vfest Trenton, t~ . J. | l | | Ground |
| 26 | 10 Jul 47 | not stated | Harmon Field, Newfoundland | l | | Ground |
| ~ | 10 Jul 47 | ~ | Hamon Field, bewfoundland | l | | Ground |
| 2g | 24 Jun 47 | not stated | Idaho | l | | Ground |
| 29 | 23 Jun 47 | not stated | Bakersfield., Calif. | 10 | | Ground |
| 30 | 7 Jan 4! | l~T | Lockbourne AB, Co1umbus, Ohio | 1 | | Ground |
| 30a | 7 Jan 4g | 1925EST | Lockbourne,!B, Columbus., Ohio | l | | Oroum |
| 30b | 7 Jan 4a | 1915EST | Lockbourne AB, Columbus, O hio | l | | Ground |
| 30c | 7 Jan 4g | 1940 | Lockbourne il, Columbus, Ohio | 1 | | Ground |
| 31 | mid-December early a.m. N orthern Arizona<br />1946 | mid-December early a.m. N orthern Arizona<br />1946 | mid-December early a.m. N orthern Arizona<br />1946 | l | | Ground |
| 32 32 | not stated | after dark | Columb us , Ohio | 1 | | llr |
| 33 | 7 Jan 41! | 133&.l'T,OO "' | Oocbnan Field, Ky. (south of) | 1 | | Ground |
| 33a | 7 Jan~ | l4000ST | Godman Field, Ky. | 1 | | Ground |
| 33b | 7 Jan~ | 1320CS'J.' | · 0odman Field, Ky. | 1 | | Ground<br />. |
| 33c | 7 Jan 4g | J..420 CST | 2100 from Oodman Field, Ky. | 1 | | Ground |
| 33d | 7 Jan 4a | 1400 | Gedman Field, Ky. | 1 | | Ground |
| 33e | 7 Jan 4g | J..430-1600 | Godman Field, Ky. | 1 | | Ground |
| 331' | 7 Jan~ | 1445 | Godman Field., Ky. | 1 | | ~ |
| 33g | 7 Jan~ | 11!54-19()6 | lladi.eomi-1.le, Ky. | l l<br />,l ~<br />I. | - , | Ground |
| 34 | 13 Oct 47 | 05}0 | l4 mi1es north of Dauphin,<br />J.lanitoba, Canada | ~ | | Ground |
| 35 | 12 Nov 41 | GQ'l.Jr a.m. | ticonderoga south of Cape at dlanco, sea (40 20 miles miles<br />o£f shore) | 2 | \ | Boat |
[page 5]
# CONFIDENTIAL
# CONFIDENTIAL (cont.)
| INCIDENT | | Hour | Location | Location | No. | Observed<br />_ From |
|-|-|-|-|-|-|-|
| No. | Date | Hour | Location | Location | Sighted | Observed<br />_ From |
| 36 | Not Stated | Not Stated | | Boise, Idaho | 1 | Ground |
| 37 | 12 Oct 47 | 1200 | | Cave Creek, Arizona | 1 | Ground |
| 38 | 10 Jun 47 | Not Stated | | Budapest, Hungary | 1 | Ground |
| 39 | 9 Jul 47 | 2330 | | Grand Falls, Newfoundland | 5 | Ground |
| 40 | 7 Jul 47 | 1600 | | Phoenix, Arizona | 1 | Ground |
| 41 | 11 Jul 47 | Not Stated | | Blendorf Field, Alaska | 1 | Ground |
| 42 | 12 Jul 47 | 04302 | ' | Elendorf Field, Alaska | 1 | Ground |
| 43 | 29 Jun 47 | 1645 | | Clarion, Iowa | 18 | Ground |
| 44 | 28 Jun 47 | 1543 | | Rockfield, Wisconsin | 7-10 | Ground |
| 45 | 28 Jun 47 | Afternoon | | Illinois | 7-10 | Ground |
| 46 | 22 Jun 47 | 1130 | | Greenfield, Mass. | 1 | Ground |
| 47 | 6 Jul 47 | Not Stated | | Fairfield-Suisun Air Base, Calif. | 1 | Ground |
| 48 | 7 Jan 48 | 1920-1955 | | Wilmington, Ohio | 1 | Ground |
| 48a | 7 Jan 48 | 1925 | | Wilmington, Ohio | 1 | Ground |
| 48b | 7 Jan 48 | 1910EST | | Wilmington, Ohio | 1 | Ground |
| 480 | 7 Jan 48 | 1930 | | Wilmington, Ohio | 1 | Ground |
| 48d | 7 Jan 48 | 1920-1950 | | Wilmington, Ohio | 1 | Ground |
| 49 | 9 Jan 48 | 2300-2315 | | Danville, Kentucky | 1 | Ground |
| 50 | 10 Jan 48 | 2200 | | Wildwood, New Jersey | One at this Ground<br />date, prev-<br />iously 1 each<br />27 Dec,3 Jan<br />all at 2000 o'clock. | One at this Ground<br />date, prev-<br />iously 1 each<br />27 Dec,3 Jan<br />all at 2000 o'clock. |
| 51 | 3 Sept 47 | 1215 | | Oswego, Oregon | 12-15 | Ground |
| 52 | 29 Jul 47 | 1450 | | Hamilton Field, California | 2 | Ground |
| 52a | 29 Jul 47 | After 1200 | | Hamilton Field, California | 2 | Ground |
| 53 | 28 Jun 47 | 1515 | | Lake Mead, Oregon | 5-6 | Air |
| 54 | 16 Jan 47 | 2230 | | North Sea (50 miles from<br />the Dutch Coast) | 1 | Air |
| 55 55 | 23 Jul 47 | 03452 | | Harmon Field, Newfoundland | 1 | Ground |
[page 6]
# CONFIDENTIAL
# CONFIDENTIAL (cont.)
| Incident<br />No. | Date | Hour | Location | No.<br />Sighted | Observed<br />From |
|-|-|-|-|-|-|
| 56 | 6 Jul 47 | 2045 | Birmingham, Alabama | 7-10 | Ground |
| 57 | 20 Jul 47 | 00152 | Aboard the Burgeo (at Sea<br />one hr. from Sydney, Australia) | 1 | Boat |
| 58 | 4 Aug 47 | Evening | Bethel, Alaska | 1 | Air |
| 59 | 14 Sept 47 | 05580CT | Necker Island | 1 | Air |
| 60 | 10 Jul 47 | 1000 | Cordroy, Canada | 1 | Ground |
| 61 | 8 Sept 47 | 2230 | Salt Lake City, Utah | 12 | Ground |
| 62 | 8 Sept 47 | 2230-2300 | Salt Lake City, Utah | 5 groups<br />each con-<br />taining<br />35-60<br />objects. | Ground |
| 63 | 29 Jul 47 | 1205 | Canyon Ferry, Montana | 1 | Ground |
| 64 | 19 Aug 47 | 2130 | Twin Falls, Idaho | Approx.<br />55. | Ground |
| 65 | 2 Jun 47 | Not stated Rehoboth Beach, Deleware | Not stated Rehoboth Beach, Deleware | 1 | Ground |
| 5558 66 | 10 Aug 47 | 2100 | Silver Springs, Ohio | 1 | Ground |
| 67 | 14 Aug 47 | 1600 | Placerville, California | 1 | Ground |
| 68 | 24 Jun 47 | Not stated | Cascade Mountains,<br />Portland, Oregon | 6 | Ground |
| 69 | 6 Aug 47 | 2230-2245 | Philadelphia, Pa. | 1 | Ground |
| 70 | 6 Aug 47 | 1045 | Philadelphia, Pa. | 1 | Ground |
| 71 | 8 Oct 47 | Not stated | Las Vegas, Nevada | 1 | Ground |
| 72 | Not stated | Not stated | Fort Richardson, Alaska | 1 | Ground |
| 75 73 | 4 Aug 47 | 1600 | Boston (10 miles NW) Mass. | 2 | Air |
| 74 | 24 Jun 47 | App. 1500 | Mt. Adams, Washington | Not Stated | Ground |
| 75 | 13 Aug 47 | 1300 | Smoke River Canyon, Idaho | 1 | Ground |
| 76 | 13 Aug 47 | Morning | Salmon Dam, Idaho | 2 | Ground |
| 77 | 3 July 47 | 1830Z | South Brookville, Maine | 10 | Ground |
| 78 | 30 Jun 47 | 0910 MST | Grand Canyon, Arizona | 2 | Air |
| 79 | Apr 47 | 1100 EST | Richmond, Virginia | 1, others on<br />other occasions | Ground |
# CONFIDENTIAL
| Incident<br />No | Date | Hour | Location | No.<br />Sighted | Observed<br />From |
|-|-|-|-|-|-|
| 80 | 7 Jul 47 | 2230-2300EDT | Arlington, Virginia | 1 | Ground |
| 81 | 7 Jul 47 | 0900 | Hickam Field, Hawaii | 1 | Ground |
| 82 | 17 May 47 | 2030-2100 | Oklahoma City, Oklahoma | 1 | Ground |
| 83 | 9 Jul 47 | 1217 | Boise (Between Boise and<br />Meridian) Idaho | 1 | A1 |
| 184 | 7 Jul 47 | 1300-1400EST | Lakeland, Florida | 5 | Ground |
| 85 | 14 Jun 47 | 1200 | Portland, Oregon | 10 | Ground |
| 86 | 6 July 47 | Not stated | Hollywood, California | 1 | Ground |
| 87 | Not stated | Not stated | Habberbishopshiem (20 miles<br />north) Germany | 1 | Ground |
| 88 | 3 Aug 47 | Afternoon | Hackensack, N. J. | 1 | Ground |
| 89 | 6 Jul 47 | 1345 | Kansas City (100 miles west),<br />Kansas | 1 | Air |
| 90 90 | 29 Jun 47 | 1300-1330 | Las Cruces, New Mexico | 1 | Ground |
| 91 | 28 Jun 47 | 2120-2145 | Maxwell Field, Alabama | 1 | Ground |
| 92 | 19 Jun 47 | 1215-1315 | Colorado Springs, Colorado | 1 | Ground |
| 93 | 11 Jan 48 | 1 1630 | Hartford, Connecticut | 1 | Air |
| 94 | 30 Deo 47 | 1926PST | Between Great Falls, Montana<br />and Fairfield, California | 1 | Air |
| 95 | 30 Dec 47 | 1925PST | Rosedale, California | 1 | Air |
| 96 | 30 Dec 47 | 1926 | Lovelock (30 miles west), Nevada | 1 | Ground |
| 97 47 | 30 Dec 47 | 1925 PST | Between Medford and Mt. Chasta,<br />Oregon | 1 | Air |
| 98 | 2 Nov 47 | Daybreak Houston, Texas | Daybreak Houston, Texas | 1 | Ground |
| 99 | 3 Jan 48 | Not stated Vassa, Finland | Not stated Vassa, Finland | 1 | Ground |
| 100 | 5 Jan 48 | Not stated | Pretarsaari, Finland | 1 | Ground |
[page 8]
•
# CONFIDENTIAL
| Incident No . | Observer ' s<br />Occupation | Jo1aneuvers | Heatner |
|-|-|-|-|
| 1 | 1 st Lt, UJAF | 1lo ne - horizontal fl1gnt | IiOt stated |
| la | :,/::,gt, 0::i,v' | 1"ot stated | .,ot stated |
| lb | Unino wn | t-:et stated | l1 ot stated |
| le | s/sgt, USAF | Not stated | ~!ot stated |
| l d | Pfc, USAF | Flying in tight circle | !f ot s tat'3d |
| le | ~fot stated | Horizontal anrl tipht circles | !lot stated |
| 2 | :Uaj, USAF | altitude Descended in from an an oscillating intennediate<br />fashion then started almost climbing to the again ground, to<br />a off very slowly high in altitude the distance. and moved | Not stated |
| 3 | liajor, USAF | ing Oscillating movement in a downward twirl- | Not stated |
| 4 | Capt, USAF | of Falling a parachute at three times the rate | ?!ot stated |
| 5 | Police Pat r olman, Dept. ?ortland | ing Dippi mot nP, ion up and down in oscillat-- | Not stated |
| 6 | Sgt, Oregon Police | Following each otner | Clea r with little<br />or tion no cloud forma |
| 7 | Patr olman, Por tland<br />Police Dept ., former<br />Air Force pilot | Not stated | Clear with little<br />or no cloud forma<br />tion |
| g | Patrolman, Portland<br />Police Dept. Pri<br />vate pilot | Str aight line formatio very n; last<br />disc fluttered rapidly in<br />side-way arc | Clear with little<br />or no cloud for.na<br />tion |
| ga | Patrolman, Portland<br />Po lice Dept . ?ri<br />vate pilot | disc Strai~ht fluttered line fonnation very rapidly ; last in<br />side-way- are | Clear with little<br />or no cloud forma<br />tion |
| 9 | Capt ., Harbot pilot | Discs wo'.lld osc illat e and SOl11131-'<br />times a full disc would be vis~<br />ib t hen l e, nothing then a half-moon at all shape , | Not stated |
[page 9]
•
# CONFIDENTIAL (cont.)
| Incident<br />•oo | ObaerTer' s<br />Ocoupad.on | Ka.neunra | Weather |
|-|-|-|-|
| 10 | Capt, United Airlines | Straight-away horizontal flight | lot stated |
| ll | Coast Guard | Horizontal flight | Kot stated |
| 12 | Deputy Sheriff | Mot stated | Not stated |
| lS | !lot stated | Not stated | Bot stated |
| 14 | Sot ste.ted | FU ppi ng around | Mot stated |
| 15 | Jot stated | Not stated | Iot stated |
| 16 | Mot stated | Hot stated | Mot stated |
| 17 | Private pilot | Straight horizontal flight | Clear as crystal |
| 18 | llot stated | Horizontal fli ght | Clear |
| 19 | Farmer | Straight course - were flying<br />about behind a the city other block apart. one | Cloudless and<br />sunny |
| 20 | lot stated | Straight course | lot stated |
| 21 | lot stated | Single file | Rot stated |
| 22 | Wot stated | Flashing | Bot stated |
| 23 | !lot stated | Horizontal flight | •ot st ated |
| 24 | lot stated | Shooting up and down | Clear |
| 25 | Not stated | Hori&ontal flight | Bright moonlight |
| 26 | llecba.nic | lot atated | Not stated |
| 27 | TWA Representative | llot stated | Clear |
| 28 | Lt Governor | lot stated | Kot stated |
| 29 | ffest 7000 hrs. Coe.st Pi lot. | Bot stated | lot stated |
| 30 | Operations Ca.pt. USAF. Officer Asst | Climbing and descending ver-<br />tioally | Solid overcast |
| 30a | VHF/DJ' O perator | Hovering, made three 360 0<br />turns another around position one place. and circled Moved<br />more. to Turns required 30-40 seo.<br />Diaaeter estimated at 2 miles. | Overcast. 1000 ft. |
# CONFIDENTIAL
| Incident<br />loo | Occupation Observer's | Maneuvers | Weather |
|-|-|-|-|
| SOb | Traffic Air Controller | Bobbing up and down | Overcast |
| 30o | lot a~ated | Climbing and de~oending | High overcast |
| 30 | or Profe11or and Bead<br />Aero Kn.gineering | Mone | Clear |
| 32 | Lt, USAP | Bone | Overcast |
| 33 | T/Sgt, USAF | Jone | High acattered olouds<br />Visibility unlimited. |
| 33a | 1,it.,Lt, USAF | Bone | High scattered |
| 336 www. | PFC | lone | lfot stated |
| 33c | Capt, USA1 | Kay have been turning | High overcast<br />with BIS |
| 33d | Capt, Us.Ar | None | High ecattered,<br />vi ei bi li ty unlimited |
| 330 | Col, Ky. State Police | Kone | Clear |
| 3:Sf | Leader Capt, USAF •a 869) (Plight | Not stated | .Not stated |
| :S3g | Unknown | Mot stated | Not stated |
| 34 | Judge | Bone | Clear |
| 35 | Second Officer.Wavy | Mone | !lot atated |
| 36 | CAA Official | Sot stated | Rot stated |
| 37 | Pilot | Kone | Clear .. ,-.'! |
| 38 | Hungarian Peasants | Not stated | !lot stated |
| 39 | Constable | None | a.tVU. ~ d |
| 40 | Not stated | Spiraled downward f'rom 5, 000<br />upward to 2,000 at f't a am 450 then angle went<br />a | Cumulus clouds |
# CONFIDENTIAL (cont.)
| Incident<br />No. | Observer's<br />Occupation | Maneuvers | Weather |
|-|-|-|-|
| 41 | Colonel, USAF | Not stated | Not stated |
| ནྟུ 42 | Major, USAF | Not stated | Not stated |
| སྐྱུ | Bus Driver | None | Not stated |
| ཎཱུ 44 | Not stated | None | Not stated |
| ཆ 45 | Not stated | Not stated | Not stated |
| རྨ 46 | Not stated | None | Cloud banks. |
| བོ 47 | Captain, USAF | Rolled from side to side | Not stated |
| ཚོ 48 | Major, USAF | Ascending and descending | Not stated |
| ཙྪཱ 48 | T/Sgt | Up and down and side to side | Cold and clear with<br />few scattered clouds. |
| 48b ཚཱ | Cpl. | Ascending and descending | Light scattered<br />clouds with haze<br />towards S/W. |
| 480 | S/Sgt | Ascending and descending very<br />rapidly | Clear with over-<br />cast in S/W. |
| 48d | Not stated | Ascending' and descending | Clear to scattered. |
| 49 | Not stated | None | Not stated |
| 50 | Knitting designer | Approaching shore from Ocean then<br />rise and fall slowly. | Not stated |
| 51 | Not stated | Not stated | Not stated |
| 52 | Capt, USA, ASST.<br />Operations Officer<br />and instructor Pilot | Horizonal left to right, right to<br />left like a guard in an airplane<br />formation. | Clear |
| 52a | 1st Lt. in Air<br />Reserves former<br />B-29 Pilot | Similar to a fighter aircrafts<br />maneuvers when accompanying<br />heavier ships. | Not stated |
| 53. | 1st Lt, USAF, Pilot | Horizonal very close formation | Not stated |
| 54 | Mosquito Pilot | Efficient controlled evasive action | Not stated |
| 55 | Government Employee | Abrupt darts | High scattered<br />condition visibility<br />15 miles. |
| 56 55 | S/Sgt, USAF | Traveling in a definite are. | Not stated |
[page 12]
# CONFIDENTIAL
# CONFIDENTIAL (cont.)
| Incident<br />No. | Observer's<br />Occupation | Maneuvers | Weather |
|-|-|-|-|
| 57 | Bridge Construction | Not stated | Clear and dark. |
| 58 | Chief Pilot-<br />Flying service | Not stated | Not stated |
| 59 | Pilot | None | Not stated |
| 60 | Storekeeper | Not Stated | Clear at dusk |
| 61 | Not stated | None | Not stated |
| 62 | Not stated | Not stated | Cloudy |
| 63 | Not stated | Hovering and fluttering, rising<br />and descending. | Scattered small<br />clouds. |
| 64 | Executive Direct-<br />or of Housing<br />Authority. | Horizonal | Overcast |
| 65 56 | Pilot | Not stated | Not stated |
| 66 | Lt. Col, GSC<br />Scientific<br />Branch Research<br />Group. | Horizonal Flight | Not stated |
| | Insurance Adjuster | None | Clear |
| 68 | Prospector | Banking | Clear |
| 69 | Not stated | Not stated | Not stated |
| 70 | Insurance Agent | Not stated | Clear |
| 71 | Capt. AC Reserves | Not stated | Clear |
| 72 | Army Officer | Not stated | Cloud formation<br />scattered above<br />10000 ft. |
| 773 | Navigator<br />(Constellation<br />type aircraft) | Not stated | 5/10 scattered<br />cumulus with<br />tops at 10000,<br />visibility 10<br />miles. |
| 74 | Prospector | Standing on edge and banking<br />in the clouds. | Not stated |
| 75 15 | Trout Farm Oper. | Rode up and down over the hills<br />and hollows of the canyon floor. | Not stated |
| 706 | County Commissioner Not stated | County Commissioner Not stated | Not stated |
# CONFIDENTIAL (cont.)
| In.ctdent Ko, | Ob ■erTer'•<br />Qo9upgt109 | Manemrp | J!eather |
|-|-|-|-|
| 77 | Astronomer | Not stated | lot stated |
| 78 | Lt, USI (P80 Pilot | lot 1t1ted | lot ■ tated |
| 79 | Weather r-,o7tff | Rot 1t1ted | Clear |
| 80 | Lt. Col. USAP | Jot ltated | Scattered Y111b111t7 clouds 10-12 ailea. |
| 81 | bplo,ee C1T11 Service | A1oendtng slowly | Cloudy |
| 82 | P1eld Bngtn,er | Bot stated | lot stated |
| 83 | Pilot | Slow roll or barrel | S<ae clouds |
| ~ | Sign Painter | Cl1Jlb1ng | Clear ...cattered cloud• |
| 85 | Pl'1Tate Pilot | lot stated | lot stated |
| 86 | Hot 1tated | 'l'm"ned to roll. a corner and seemed | Clear |
| 87 | U. S. Army | Descended slowly and then<br />dropped in a spiral motion, | ~ot stated |
| 88 | Not stated | Not stated | N ot s tated |
| 89 | M ajor, USAF | dot stated | CAVU |
| 90 | Administrative Rocket Sonde Section Asst, | Not at~t ed | Clear |
| 91 | Captain | Trave ling in zig-zag course | Clear |
| 92 | Railroad Employees | Climbing, diving and reversal<br />of enry direction few aeoonds. whioh happened | Cl e ar alld 1unny |
| 993 | Capt, USAP | Shooting 45° angle toward, the eaat at | Not stated |
| 94 | L~ C ol, H q, EPlf | Descending to slow down vertically on nearing - the aeaned<br />earth | •ot 1tated |
| 95 | C-47 orew | Not sta.ted | Not stated |
| 96 | Bot stated | Bot stated | Not stated |
| 97 | Airplan e crew | Not stated | tiot &tnted |
| 98 | Immi gration Service | Appeared its descent to be spinning in | lot stated |
| 100 99 | Not stated | Bot atated | lot stated |
| | lfot stated | ?lot stated | Not ata.ted |
# CONFIDENTIAL (cont.)
## Incident
| No. | Color | Shape | Size | Sound |
|-|-|-|-|-|
| 1 | Silvery | Not stated | Not stated | Not stated |
| la | | | | |
| lb | | | | |
| lc | Silvery | Saucer shaped | Not stated | None |
| ld | Reflected the sun's<br />rays | Disc | Not stated | Not stated |
| le | Silvery | Disc | Not stated | None |
| 2 | Aluminum colored<br />ssurface | Thin metallic ob- Pursuit ship<br />ject, unconventional<br />shape | Thin metallic ob- Pursuit ship<br />ject, unconventional<br />shape | Not stated |
| 3 | Yellowish-white | Spherical | 510 ft, diameter | Not stated |
| | White aluminum | Distinct oval out- 50 ft. None<br />line; two projec-<br />tions on upper sur-<br />face which might<br />have been thick<br />fins or nobs. These<br />crossed each other<br />at intervals, sug-<br />gesting either ro-<br />tation or oscilla-<br />tion of slow type | Distinct oval out- 50 ft. None<br />line; two projec-<br />tions on upper sur-<br />face which might<br />have been thick<br />fins or nobs. These<br />crossed each other<br />at intervals, sug-<br />gesting either ro-<br />tation or oscilla-<br />tion of slow type | |
| 5 | Not stated | Round | Not stated | None |
| 6 | Whitish-brown | Disc | Not stated | None |
| 7 | Aluminum | Disc | Not determined | None |
| 8 | White | Disc | Out of sight be-<br />fore detailed ob-<br />servation made | None |
| 8a | White | Disc | Out of sight be-<br />fore detailed ob-<br />servation made | None |
| 9 | Like shiny chro-<br />mium hub cap | Diso | Not stated | Not stated |
| 10 | Not stated | Thin and smooth<br />on bottom; rough<br />appearing on top | Not stated | Not stated |
# CONFIDENTIAL (cont.)
## Incident
| NO. | Color | Shape | Size | Sound |
|-|-|-|-|-|
| 11 | White | Saucer | Not stated | Not stated |
| 12 | Not stated | Like flock of<br />geese | Not stated | Low humming<br />Bound |
| 13 | Resembled metallic | Not stated | Not stated | Not stated |
| 14 | Like a new dime | Like a new dime | Like a new dime | Not stated |
| 15 | Silver | Not stated | Not stated | Not stated |
| 16 | Not stated | Diso | Not stated | Not stated |
| 17 | Mirror bright | Approximately<br />circular, no tail | Diameter equal to<br />distance between<br />outboard engines<br />of DC 4 | Not stated |
| 18 | Yellow | Ball | Not stated | Not stated |
| 19 | Reflected the sun<br />brilliantly | Like cigars -<br />much longer than<br />wide | Not stated | None |
| 20 20 | Silver | Round | About 12 inches in<br />diameter | None |
| 21 22 | Dirty white | Between circle<br />and oval in-<br />verted saucer | 175-250 ft. diameter<br />12 ft. thick | Like electric<br />motor or dy-<br />namo |
| 22 | Shiny silvery | Slim body | Quite large | Not stated |
| 23 | Bright and silvery | Half-circle | Not stated | Not stated |
| 24<br /><br />25 | Glistened in sun | Too far away to<br />determine shape | Too far away to<br />determine shape | None |
| 25 | Luminous | Flying saucer -<br />no tail | Not stated | Not stated |
| 26 | Not stated | Not stated | Not stated | Not stated |
| 27 | Silvery | Circular in shape<br />like a wagon wheel | Same span as C-54<br />at 10,000 ft. | Not stated<br />A |
| 28 | Not stated | Comet-11 ke | Not stated | Not stated |
| 29 | Not stated | Almost round | Not stated | Not stated |
| 30 | White (light) | Not stated | Not stated | None |
# CONFIDENTIAL (cont.)
## lnoident
| No. | Color | Sha.pc | Size | Sound |
|-|-|-|-|-|
| 30& | Amber | Round or oval | C-47 airplane | Jliono |
| !Ob | Bright white to amber | Cone-shaped. blunt<br />on top orr and taper<br />ing bottom toward ' | Rnonnou• | None |
| 30c | White lligbt) | RoWlld | Comparable 'to run-<br />way light | Bone |
| 31 | White | Not stated | lot stated | ltone |
| 52 | Amber | Mot stated | tiot stated | !lone |
| 33 | Sun flashes on metal<br />or metallic | Roughly circular | At the distance and<br />altitude the object the<br />appeared a11Ter ~o be dollar<br />size of | lone |
| 33a | ffll.1 ·rurnod te or to luminous. more<br />red aa the be aun aet | Round teudi og to<br />be conical | Unknown a.na distance - altitude too<br />great | Iona |
| 33b | ~ot auted | Cone. topped with<br />red | Jot stated | lone |
| :53e | Si lver with shadow | Raindrop | Unlcnown - believed<br />to be lar~ | lJnJcnoa |
| 53d | 1'h1. te | Round cone ~haped at time• - | Uneert&in because<br />of distance | None |
| 53e | lfhi . te | Round | l/4: she full moon | lone |
| 33.f | l(atallio | Bot stated | Tremendous | Not stated |
| SSg | "lfot stated | Cone | 100 ft. high.<br />43 .rt. acrose | !lone |
| 34 | Redish tinge | Round | Large gre.pef'rui t | Ion• |
| 35 | Fire oolor | Ball | liot stated | llot atatecl |
| 36 | )lot stated | Bot stated | Mot at&.ted | Bot stated |
| 37 | Reddish with blue<br />with background.. Black<br />white baokground | lot stated | S ft. from point of<br />view | lone |
| 38 | SilTer | Ball | .Not ate.ted | Mot stated |
# CONFIDENTIAL (cont.)
## lnoident (cont.)
| Incident<br />No. | Color | Shape | Size | Sound |
|-|-|-|-|-|
| 39 | Phosphorus | Egg-shaped dises | Not stated | Not stated |
| 40 | Gray | Elliptical | 20-30 ft. | Noise like jet<br />aircraft prior<br />to its appear-<br />ande. No<br />audible sound<br />heard while<br />object was in<br />view. |
| 41 | Aluminum | Round | 3 ft. diameter | Not stated |
| 42 | Grayish | Balloon | 10 ft diameter | Not stated |
| 43 | Dirty white | Between a circle and<br />an oval (Inverted<br />saucer) | 12 ft thick and<br />175-250 ft diameter | Electric Motor<br />or dynamo |
| 典 44 | Not stated | Flying Saucers<br />(not actually des-<br />cribed as being<br />this shape) | Not stated | None |
| 45 | Not stated | Not stated | Not stated | Not stated |
| 46 | Silvery white | Round | Small | Not stated |
| 47 | No definite<br />color top<br />side reflect-<br />ed light. | No definite shape | C-54 airplane | Not determined<br />due to the noise<br />of airplane. |
| 48 | Red | Flaming Red cone | Not stated | Not stated |
| 488 | Bright light<br />changing to<br />red then to<br />white or yellow | Circular-11ke a star<br />in the sky only larger. | Very large compared<br />to an aeroplane light. | None |
| 486 | Red - when<br />descending | Cone | Not determined | Not stated |
| 480 | Red when moving<br />then grean and<br />black to red. | Not stated | Not stated | Not stated |
| 48d | Yellow or flame<br />colored. | Not stated | Not stated | Not stated |
| 49 44 | Not stated | Pencil shaped object | Not stated | Not stated |
# CONFIDENTIAL
| Incident | | | | |
|-|-|-|-|-|
| No. | Color | Shape | Size | Sound |
| 50 50 | Stated as<br />queer light. | Referred to as saucer<br />but not stated as being<br />of this definite shape. | Not stated | Not stated |
| 51 | Silver | Round | Not stated | Not stated |
| 52 | White, shiny | Circular like a ball<br />on the bottom but not<br />completely round. | 15-25 ft Diameter | Not stated |
| 52a | Milk white | Not stated | Not stated | None |
| 53 | White | Circular | 36 inches diameter | Not stated |
| 54 | Not stated | Not stated | Not stated | Not stated |
| 55 | Redish | Not stated | Not stated | None |
| 56 | Dim glow of<br />light | Round | 2 ft. diameter | None |
| 57 | Silver to Red | Not stated | Not stated | Not stated |
| 58 | Black | Saucer (not definitely<br />stated as being this<br />shape) | Larger than C-54<br />airplane | Not stated |
| 59 | Incandescent<br />light without<br />appreciable<br />blue and no<br />reddish tinge. | Not stated | Not stated | Not stated |
| 60 | Flame color | Disc shaped (the after<br />glow made it look like<br />a cone) | Barrel Head, dinner<br />plate and the size<br />of a plane flying<br />high. | Not stated |
| 61 | White and<br />111uminated | Not stated | Size of Pigeons | Not stated |
| 62 | Yellowish<br />white | Not stated | Small | Not stated |
| 63 | Gleamed and<br />Shimmered | Disc (not actually<br />stated as being of<br />this shape) | 3 ft. diameter and<br />of no great thick-<br />nеsв. | Not stated |
| 64 | Color similar<br />to electric | Not stated<br />light. | Not stated | Not stated |
| | Not stated | Not stated | 15 inches diameter | Not stated |
| 565 66 | Bright Orange | Not stated | Not stated | Not stated |
| 67 | Mutal color<br />highly polish<br />ed chromium. | top surface slightly<br />curved-larger in front<br />than in the rear.<br />NND 927545 | 4-6 ft in length<br />and 10-14 inches<br />wide. | Not stated<br /><br />CONFIDENTIAL |
# CONFIDENTIAL (cont.)
## Incident
| No. | Color | Shape | Size | Sound |
|-|-|-|-|-|
| 68 | Not stated | Disc appeared to have<br />a tail. | 30 ft diameter | None |
| 67 69 | White | Not stated | Not stated | Buzzing sound. |
| 70 | Not stated | Giant fire cracker | Not stated | Buzzing sound<br />not as loud<br />as a rocket<br />ship. |
| 71 | Not stated | Not stated | Not stated | Not stated |
| 72 | Silver | Sphere was not like<br />saucer or disc. | 2-3 ft diameter | Not stated |
| 73 | Deep Gold | Elliptical | 15 ft long 2-3 ft<br />in length. | Not stated |
| 74 | Not stated | Tapered sharpely to a<br />point in the front end. | 30 ft. diameter | None |
| 75 75 | Sky blue | Oblong like a broad rim<br />hat with a low crown. | 20 ft. long and<br />10 ft. thick. | Made a<br />swishing sound. |
| 76 | Not stated | Not stated | Not stated | Like the echo<br />of a motor. |
| 77 | Light colored | Only concrete evidence<br />of form appeared on the<br />left tangent of the group. | 50-100 ft wide. | Loud roar |
| 78 | Light gray | Circular | 8 ft. diameter | Not stated |
| 79 | Silver | Not stated | Larger than a<br />Pibal balloon when<br />observed through a<br />theodolite. | Not stated |
| 80 | Reflected white<br />light. | "Blob" | Small airplane | None |
| 81 | Silver | Large Balloon with silver Large Not stated<br />disc below it, no attaching<br />cables were noticed. | Large Balloon with silver Large Not stated<br />disc below it, no attaching<br />cables were noticed. | Large Balloon with silver Large Not stated<br />disc below it, no attaching<br />cables were noticed. |
| 82 | Frosty white | Round and flat | Equal to bulk of<br />6 each, B-29 air-<br />planes with dia-<br />meter to thickness<br />ratio of 10-1. | A slight<br />swishing. |
| 83 | Black | Round | Twenty-five cent<br />piece. | Not stated |
# CONFIDENTIAL (cont.)
## Incident (cont.)
| Incident<br />_ No. | Color | Shape | Size | Sound |
|-|-|-|-|-|
| 84 | Shinny | Round | Not stated | More or less<br />Shrill. |
| 85 | Not stated | Resembled the XF5U-1. | Not stated | Not stated |
| 86 | Not stated | Not stated | Not stated | Not stated |
| 87 | NotSstated | .<br />Not stated | Not stated | Not stated |
| 88 | Not stated | Flying disc (not ac-<br />tually described as<br />being of this shape) | Not stated | Not stated |
| 89 | Silvery | Round disc shaped object | 30-50 ft. diameter | Not stated |
| 90 | Reflected<br />light | Uniform with no protu-<br />berances such as wings<br />of an airplane | Not stated | Not stated |
| 91 | Light | Not stated | Not stated. | None |
| 92 | Silver | Not stated | Small | Not stated |
| 93 | Bluish center<br />with rod on<br />its edges | Appeared to be a disc | Resembled a shooting<br />star; however, ob-<br />servers not certain | Not stated |
| 94 | Not stated | Not stated | Not stated | Not stated |
| 95 | Not stated | Not stated | Not stated | Not stated |
| 96 | Not stated | Not stated | Not stated | Not stated |
| 97 | Flash of<br />light | Not atated | Not stated | Not stated |
| 98 | Bright light | Almost round or perhaps<br />oval or saucer-shaped | 26-30 miles diameter | Not stated |
| 99 | Shining | Brightly shining object<br />with long tail | Not stated | Not stated |
| 100 | Shining | Not stated | Not stated | Not stated |
# CONFIDENTIAL (cont.)
## Incident (cont.)
| Incident<br />No. | Exhaust<br />Trail | Heading | Altitude Ft. | Speed | Effect on | Clouds |
|-|-|-|-|-|-|-|
| 1 | None | 3200 | 1000-8000 ft. | 300 mph | Not stated | |
| la | | | | | | |
| lb | | | | | | |
| ic | Not stated | Northwest | 7500-8000 ft. | 350-400 mph | Not stated | |
| ld | Not stated | Northwest | 7000-8000 ft. | 300-400 mph | Not stated | |
| le | Not stated | Northwest | 8000 ft. | 300-400 mph | Not stated | |
| 2 | Not stated | Not stated | From very near<br />the ground to<br />very high | Not stated | Not stated | |
| 3 | Not stated | West to east | 10000-12000 ft. | 200-225 mph | Not stated | |
| 4 | Not stated | North of due<br />east | Under 20000 ft. | Slower than<br />maximum speed<br />of P-80 | Not stated | |
| 5 | Not stated | Two flying<br />south - 3<br />flying east | Not statedd | Great speed | Not stated | |
| 6 | Not stated | Northwesterly | Undetermined | Terrific | Not stated | |
| 7 | None | Southwest | 30000 ft. | Terrific -<br />faster than<br />any object<br />ever seen<br />by him | Not stated | |
| 8 | None- | South | 40000 ft. | Terrific | Not stated | |
| 8a | None | South | 40000 ft. | Terrific | Not stated | |
| 9 | Not stated | South | High over<br />Globe Mills | Terrific | Not stated | |
| 10 | None | Northwest | Not stated | Cruised for<br />45 min. at<br />conventional<br />airline speed<br />(180 mph) then<br />rapidly dis-<br />appeared | Not stated | |
| 11 | Not stated | Over north end<br />of Lake Wash-<br />ington | Not stated | Not stated | Not stated | |
# CONFIDENTIAL (cont.)
## Incident (cont.)
| Incident<br />No. | Exhaust<br />Trail | Heading | Altitude Ft. | Speed | Effect on Clouds |
|-|-|-|-|-|-|
| 12 | Not stated | Not stated | Not stated | Not stated | Not stated |
| 13 | Not stated | 3 west to<br />east. 1 north | Did not appear<br />very high | Traveling so<br />fast they<br />were out of<br />sight in east<br />in 2-4 seconds | Not stated |
| 14 | Not stated | Not stated | Not stated | Moving slowly<br />over sandy<br />district | Not stated |
| 15 | Not stated | 1 headed<br />Southeast.<br />2 headed<br />northeast | High | Not stated | Not stated |
| 27 16 | Not stated | Not stated | Not stated | Not stated | Not stated |
| 17 | Not stated | north to south<br />about 170° | 9500 ft. | Not stated | Not stated |
| 18 | Trail stream-<br />ing out be-<br />hind like<br />vapor trail<br />behind air-<br />plane on<br />misty day | Seenhoter<br />westend<br />of Toronto | Not stated | Not stated | Not stated |
| 19 19 | Like slight<br />trace of steam.<br />Disappeared<br />immediately. | West to east | One mile high | Very fast | Not stated |
| 20 | Not stated | Southwest | About 1500 ft. | Fast | Not stated |
| 21 | Not stated | N.N.W. | 1200 ft. | About 300<br />mph | Not stated |
| 22 22 | Not stated | S.W. of S. | 7000 ft. | Slower than<br />two-motored<br />army plane | Not stated |
| 23 | Not stated | Not stated | 3000 ft. | Not stated | Not stated |
| 24 | Cloud-like<br />vapor re-<br />tained shape<br />and persisted<br />for over an<br />hour | Southeast | Very high | Very fast | Not stated |
[page 23]
•
# CONFIDENTIAL
| Incident<br />Ho. | B.xhaust<br />Trail | Heading | Altitude Ft. | Speed | Effect on Clouds |
|-|-|-|-|-|-|
| 25 | Wot stated | Bast | High | Fast | Not stated |
| 26 | Bluish-black | Not sta.ted | Bot stated | llot stated | Cut throup a clear cloud• path |
| 27 | Bluish-black<br />15 mi. long | Not stated | 10000 ft. | Fast | Seemed to out<br />0loud1 open |
| 28 | Not stated | Not stated | Not stated | Did not<br />moveo Seemed to<br />go below<br />horizon<br />with of earth rotation | Bot stated |
| 29 | Not stated | 10 flying<br />north; reverse on course<br />there were only | High<br /><br />7 | 300-400 mph | Bot ate.ted |
| 30 | None (ap-<br />peared to<br />ha.ve streaks bluish out<br />t'rom aides | West | 3000 | Slow | Bot stated |
| 30a | Five times<br />length ot<br />object | 1200 | Prom .,ery near<br />g?'Ound to 1000 | rt. 500 a, tter mph 1 t<br />to atartecl<br />n.e1n1ty le&"ff | Jlot stated |
| S0b | Small streak<br />trailing object | 8.8.Wo | 2000-3000fft. | bceeding<br />600 aph | Bot ate.ted. |
| 300 | Wot stated | Kot atated | di!teNn.~ al•<br />titudea ; | Jfotionlesa | lot stated<br />~-~------ |
| SI | White., heavy | West to eut | 20000-50000 ft. | 600-~00 mph | Bot 1ta1;ecl • • |
| 32 | lone | Stationary | 3000 tt. | Stat1anary | "lone |
| 33 | lone | lone visible | Unknolm | nom n.aible | Ione |
| 33a | Jfone | 210° from<br />Godman Field | Extremely high | Stationary | !lone |
| 33b | None | Not stated | Not stated | Not stated | Bot sta:t;ed |
# CONFIDENTIAL
| Incident<br />No. | Exhaust | Heading | Altitude Ft. | Speed | Effect on Clouds |
|-|-|-|-|-|-|
| 330 | Not seen | Appeared to be<br />stationary. | Very high. | Appeared<br />to be<br />stationary. | None |
| 33d | None | 210° from<br />Godman Fld. | Uncertain-<br />very high. | Stationary.Could be seen<br />through cirrus | Stationary.Could be seen<br />through cirrus |
| 33e | None | 210° from<br />Godman Pld. | 25000 ft. | Stationary. None | Stationary. None |
| 338 | Not stated | Approx. 210°<br />from Godman Fld. | 15000 ft. | 500 mph | Not stated |
| 338 | Not stated | Southwest | 4 miles | 10 mph | Not stated |
| 34 | None | West to east | Not stated | Speed of a<br />meteor or<br />falling | None<br /><br />star. |
| 35 35 | Stream of<br />fire. | Northwesterly | Not stated | 700-900 mph Not stated | 700-900 mph Not stated |
| 36 | Not stated | Northeast | Not stated | Not stated Not stated | Not stated Not stated |
| 37 | Not stated | Northeast | 8000-10000 ft. | 350 mph | Not stated |
| 38 | Not stated | Not stated | Not stated | Not stated Not stated | Not stated Not stated |
| 39 | None | East | 30000 ft. | Very fast Not stated | Very fast Not stated |
| 40 | Not stated | Appeared from<br />northeast. | 5000 ft. | 400-600 mph | Not stated |
| 41 | Not stated | South | Not stated | Great | Not stated |
| 42 | Not stated | Northwest | 1500 | 100 mph | Not stated |
| 43 | Not stated | First group<br />S S/E, second<br />group N/W. | 1200 | 300 mph | Not stated |
| 44 | Not stated | South | Not stated | Fast | Not stated |
| 45 | Not stated | Not stated | Not stated | Not stated | Not stated |
| 46 | Not stated | Northwesterly | 1000 | Faster<br />than an air-<br />plane. | Not stated |
| 47 | Not stated | Southwesterly | 10000 | Faster than<br />any aircraft<br />he had ever<br />seen. | Not stated |
| 48 44 | Gaseous green<br />mist. | S/W when it<br />left the<br />vicinity. NND | Not stated<br /><br />927545 | Gained and<br />lost altit-<br />ude at a | Not stated |
# CONFIDENTIAL (cont.)
| Incident<br />No. | Exhaust<br />Trail | Heading | Altitude Ft. | Speed Effect on Clouds |
|-|-|-|-|-|
| 48a | Very faint<br />exhaust trail<br />when moving. | S/W when it left<br />the vicinity. | Not stated | Left Not stated<br />vicinity<br />at very<br />high speed. |
| 48b | Greenish<br />mist when<br />descending. | S/W when it left<br />the vicinity. | Not stated | Not stated Not stated |
| 480 | Not stated | 210 degrees when<br />it left the vic-<br />inity. | 15000-20000 | Not stated Not stated |
| 48d | None | Approximately<br />due west when it<br />left the vicinity. | From 4000 to<br />very high. | Slow Not stated |
| 49 | Long trail<br />of smoke. | West | Very high | Not stated Not stated |
| 50 | Not stated | Shoreward | Not stated but<br />said to be<br />quite close. | Slow until Not stated<br />over land<br />then higher<br />speed while<br />leaving. |
| 51 | Not stated | Not stated | High | Not stated Not stated |
| 52 | None | Southward | 8000-10000 | Made a P-80 Not stated<br />look like it<br />was motion-<br />less in the<br />air. |
| 52a<br />酸奶味 | Not stated | 120° | 6000 | Approximate- Not stated<br />ly 750 mph. |
| 53 | Not stated | 120° | 6000 | 285 mph. Not stated. |
| 54 | Not stated | North Sea to<br />Norfolk | 22000 | Equal to Not stated<br />or greater<br />than a Brit-<br />ish Mosquito. |
| 55 55 | Not stated | NNE | 10000 | High vel Not stated<br />ocity, stated<br />to be faster<br />than convent-<br />ional airplane. |
| 56 56 | Not stated | South East | 2000 ft | 500-600 mph. Not stated |
[page 26]
# CONFIDENTIAL
# CONFIDENTIAL (cont.)
| Incident<br />No. | Exhaust<br />Trail | Heading | Altitude Ft. | Speed | Effect on Clouds |
|-|-|-|-|-|-|
| 57 52 | Not stated | NNE (30° E of<br />true North on<br />horizonal plane. | 30° off the<br />horizon at<br />an estimated<br />1/4 mile range. | High vel-<br />ocity, sta-<br />ted to be<br />faster than<br />a tracer<br />bullet. | Not stated |
| 559 58 | Not stated | N/W | 1000 | 510 mph. | Not stated |
| | Not stated | 350° later<br />changed to<br />109°. | 9500-10000 | 1000 knots | Not stated |
| 60 60 | Light flame<br />color. | From N/W head-<br />ing Eastward. | 6000 | Very high<br />velocity. | Not stated |
| 61 | Not stated | Northern | 2000-3000 | Faster than<br />birds. | Not stated |
| 62 | Not stated | Not stated | Several<br />thousand ft. | High rate<br />of speed. | Not stated |
| 63 | Not stated | Northeasterly | 3000 | Tremendous<br />Speed. | Not stated |
| 4 64 | Not stated | Northeasterly | Not stated | Terrific | Not stated |
| 65 | Not stated | West to East | 1000 | 1000-1200mph | Not stated |
| 66 | Long stra-<br />ight white<br />streak sim-<br />ilar to the<br />streak left<br />by a tracer<br />bullet. | North to South | Low | Required 34<br />seconds to<br />travel 70°<br />arc. | Not stated |
| 67 | White trail<br />of smoke. | Not stated | 500-1000 | Terrific | Not stated |
| 68 | Not stated | Southeasterly | 6000 | Not stated | Not stated |
| 69 | Thin streak<br />of greyish<br />color. | South | Not stated | Very fast. | Not stated |
| 70 70 | Either smoke<br />or conden-<br />sation last-<br />ing 2 seconds. | NE to SW | 1000-3000 | 400-500 | Not stated |
| 71 | May have<br />been smoke<br />or vapor | Southeast then<br />turned and went<br />west. | Not stated | 7000800 | Not stated |
# CONFIDENTIAL
| Incident<br />No. | Exhaust<br />Trail | Heading | Altitiude Ft. | Speed | Effect on Clouds |
|-|-|-|-|-|-|
| 27 72 | None | South | Below 10000 | Tremendous | Not stated |
| 73 | None | Easterly<br />approximately<br />110° magnetic. | 7000 | 175 mph | Not stated |
| 74 | Not stated | Not stated | Not stated | Greater<br />than any-<br />thing ever<br />witnessed. | Not Stated |
| 75 | None | East to west | 75 | Not stated | Not stated |
| 76 | Not stated | Not stated | 4000-6000 | Not stated | Not stated |
| PREP 77 | Not stated | Northwest (True) | Not stated | 600-1200 | Not stated |
| 78 | Not stated | Straight down. | Decreasing from<br />approximately<br />25000. | Inconceivable | Not stated |
| 79 | Not stated | East to West | Less than 15000 | Not stated | Not stated |
| 80 | None | Southeast | Less than 500 | Computed at<br />1350 mph,<br />however ap-<br />peared to<br />move with<br />the speed<br />of a jet<br />aircraft. | Not stated |
| 81 | Not stated | Northwest | 6000 | Not stated | Not stated |
| 82 | None | 350° | 10000-18000 | Three times<br />that of a<br />jet aircraft. | Not stated |
| 83 | Not stated | Not stated | 11000 | Not stated | Not stated |
| 84 | Not stated | Northeast | 7500 | Not stated | Not stated |
| 85 | Not stated | North | 8500 | 350 mph | Not stated |
| 86 | Not stated | Northward | Not stated | Not stated | Not stated |
| 87 40 | Not stated | Not stated | from 5000 | Not stated | Not stated |
| 88 | Not stated | Not stated | 200 yards | moving rap-<br />pidly | Not stated |
| 89 | Not stated | East | 11000 | 210 mph | Not stated |
# CONFIDENTIAL
| Incident<br />No. | Exhaust<br />Trail | Heading | Altitude Ft. | Speed | Effect on Clouds |
|-|-|-|-|-|-|
| 90 | One witness<br />thought he<br />saw vapor<br />trails | Northerly | 8000-10000 | Not stated | Not stated |
| 91 | Not stated | Disappeared<br />in the south-<br />west | Great height | High rate<br />of speed | Not stated |
| 92 | Not stated | West | Above 1000 | Great speed | Not stated |
| 93 | None | Dropped from<br />sight on north<br />side of Mt.<br />Tom near<br />Holyoke, Mass. | Not stated | Very high<br />velocity | Not stated |
| 94 | Green and<br />blue flames | Descending ver-<br />tically | From 13000 | Very high<br />rate of<br />speed | Not stated |
| 95 | Several colors<br />of flames -<br />red and green<br />predominating | Eastward | Low | Very high<br />rate of<br />speed | Not stated |
| ៖ | Not stated | Not stated | 1200-1300 | Not stated | Not stated |
| 97 | Not stated | Not stated | Not stated | Not stated | Not stated |
| ៖ 98 | Not stated | Not stated | Not stated | Not stated | Not stated |
| ៖ 99 | Not stated | West to east | Not stated | Not stated | Not stated |
| 100 | Grey streaks<br />were left in<br />sky | North to south | Not stated | Not stated | Not stated |
[page 29]
CONFIDENTIAL
## NOTE: Incident #18
It has now been definitely determined that both the photograph and story were a hoax, perpetrated for publicity and money.
## Incident #84
The person making the report on this incident was determined to be an excitable person, very talkative, and possessing an ex- aggerated, imagination and inclined to impress people with his continuous chatter.
[page 30]
| Direction | Count |
|---|---|
| NW | 63 |
| N | 38 |
| NE | 9 |
| E | 22 |
| SE | 22 |
| S | 34 |
| SW | 14 |
| W | 5 |
**Additional Data:**
* Circling: 15
* Straight down: 3
* Direction Indefinite: 64
* Direction Not Stated: 61
**Note:** Where an undetermined number of objects were reported, the minimum number of objects are plotted. Same object reported by different people only shown once.
[page 31]
Ine 2
CONFIDENTIAL
NND 927545
[page 32]
CONFIDENTIAL
NND 927545
[page 33]
# Identification of Subject Matter (as per sample)
MCIA
MCIT
19 Feb 48
1
# Identification of Subject Matter (as per sample) (cont.)
1. Reference is made to the films taken by Mr. Rhoades (Incident #40) which were forwarded for examination. The following data were derived from a study of the specimen:
a. It is concluded that The image exhibits a "tail" indicating the proper type of distortion due to the type of shutter used, the speed of the object and the fixed speed of the shutter. This trailing off conforms to the general informa- tion given in the report.
# Identification of Subject Matter (as per sample) (cont.)
b. The report states the object was seen at approximately 2000 feet at the time of exposure. The observer also reports being able to see clearly a canopy of enclosure. The visual acuity of an average person would allow for this perception, but certainly not much further as the subject had low visual contrast, being gray against a gray sky. If we can establish the distance from camera to subject, we will have quantity #1. The report states that a 620 camera was used, indicating several possibilities, since the 620 is nomenclature for the spooling and width of the film we may have negatives 2 x 24", 2 x 5" and 2 x 4. The sample submitted had been out and it was not possible to establish the exact frame size. The 2 x 24" si se was ruled out, leaving 2 x 3" and 2 x 4. If it were the former, then the focal length of the lens would be 4", and using 2000 feet as the approximate subject distance and the image size at 7/64", we have an approximate size of 44 feet as the diagonal of the object. Now if we choose the latter value of 5" for focal length, we have an approxi- mate value of 55' for the diagonal. Points of measurement are indicated from x to x on Exhibit "A".
Inc 7
CONFIDENTIAL
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# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
SEVERAL MONTHS AGO people on both sides of the Atlantic rushed into print with claims of having observed queer, saucer-shaped aircraft which flew very fast. Some main- tained, indeed, that they had seen squadrons of such mysterious objects; others described vividly how these celestial saucers were able to descend vertically. All agreed on the saucer-like shape.
Sceptics considered that, for non-aeronautical people living far from the former playgrounds of V.1, V.2, and all the rest of Hitler's "civilizatory practices, flying saucers might indeed constitute phenomena of threatening aspect, from their experi- ence of domestic disagreements. Doctors, however, hastened to assure the World that saucer-shaped or lenticular objects could well be nothing more than specks in the lenses of the eyes of the observers the so-called musae volantes associated with high blood pressure. Teetotallers blamed the sorry consequences of imbibing intoxicating liquors for the observations. On the
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
Key Information:
* **Project Name:** Turbine flying machine
* **Designer:** Gustave Koch (Munich engineer)
* **Year:** 1893/1894
* **Type:** Tailless monoplane of low aspect ratio
* **Propulsion:** Ducted fan
* **Engine:** 50 h.p. steam engine was planned
* **Design Feature:** Intelligent anticipation in the duct design.
Fig. 1. Turbine flying machine" (project) of the Munich engineer Gustave Koch, 1893/1894. Tailless monoplane of low aspect ratio, propelled by a ducted fan. A 50 h.p. steam engine was deemed sufficient for this flying motor car. The design of the duct shows intelligent anticipation.
The arrows signify the direction of the air flow against the win g. The terms ptero id (feather-like) and apterold have Fig . 2 (Right).- Definitlon of the aspect rat io of an aerofoil. been introduced by F. W . Lanchester.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
other hand, the U.S. Air Force considered the matter serious enough to warrant investigations into the incidents which had been reported.
In the meantime, the occurrence of Flying Saucers has ceased to be news. Presumably, they have all landed. [A new crop was reported in THE AEROPLANE for January 16 last under the heading "Tuppence Coloured."-ED.]
## Aeronautical Antiquities and Iniquities
As a matter of fact, saucer-shaped aeroplanes are not quite as new as some people have tried to make out. (Fig. 1.) Quite a number of aircraft have been constructed and flown with wings of the ring or disc type which could well have been mis- taken for saucers, hat-brims, spades, doughnuts, diamonds, Greek letters, pancakes, flat-fish, geometrical symbols, dinner plates, and other entirely non-aeronautical commodities.
Moreover, it is quite true, and not even a minor secret, that, at present, aeronautical engineers are paying increased attention to such queer wing shapes; disc wings, for instance, permit certain disadvantages of conventional wings to be overcome. It is even thought that such shapes have been neglected too long.
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# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Aeronautical Antiquities and Iniquities (cont.)
favour of the "well-tried" convention of "normal" wings. For these reasons, a study of the history of the use of low aspect ratios in wing design will be of interest.
Spiritually, the fathers of such aeronautical exhibits were Englishmen. They were people of good reputation and by no means suspect of aerodynamic perversion.
F. W. Lanchester was undoubtedly the first aerodynamicist to give thought to aeroplane wings of circular or square shape. In his book published in 1907, he referred expressively to such apteroid wing shapes (Fig. 2) and advanced the view that Newton's law was valid for these. The correctness of this view was experimentally proved 30 years
In a previous article on Stalling Charaics of Tailless Aeroplanes" (THE AEROPLANE for August 15, 1947), the early interest taken by F. (now Sir Frederick) Handley Page in the stalling qualities of wings of low aspect ratio was mentioned. He showed, in a paper read in April, 1911, that marginal vortices and pressure-equalizing flow around the tips were responsible for the delay of flow separation which had been observed at high incidences.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Aeronautical Antiquities and Iniquities (cont.)
He stated, in this connection:-".. With planes of high aspect ratio (i.e., with slender wings of normal span/chord ratio), there is not the same facility for the "feeding in of fresh air at the plane sides (i.e., at the wing tips) to act as a link between the plane and the live stream, and therefore the live stream leaves the plane's back at an earlier stage than in showed the case case of the plane of lower aspect ratio..." He then some experimental evidence for the delay of flow separation with decrease of the aspect ratio and for the greater maximum lift of such wings.
When Lanchester published his book, man was just begin- ning to spread his wings, and in order to fly with a minimum expenditure in power, wings of fair aspect ratio were a neces- sity. Nevertheless, there were a few early aeroplanes, notably the little "Demoiselle monoplane of Santos Dumont (1909- 1910), which had an aspect ratio of only 2 and proved to be quite successful.
One of the earliest attempts at a genuine "apteroid" aero- plane was an experiment by a German architect, Flick-Reinig (1910). It had a span of 7 ft., and performed in hops only.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Annular Aerodynamics
A simple experiment with some paper and a pair of scissors shows that the sinking speed of a circular disc loaded with a paper clip is decreased when a hole of sufficient diameter is cut out in the centre (Fig. 3). This justifies the development from the circular disc wing to the annular aerofoil. The theory of the phenomenon is still somewhat obscure.
(Having tried this experiment, we can confirm that the char- acteristics of an annular aerofoil are certainly very different from those of the plain disc aerofoil. Our own experiments were admittedly somewhat limited in scope and we were unable to form more than an impression of the relative erofoil. Our speeds; it did, however, appear to be less with the annular main conclusions were that cutting a 2.25-in. diameter hole in a 5.375-in. diameter disc, resulted in a much flatter glide; the stall was not so abrupt, and the stability in the glide was improved. We were so fascinated with the experiment that we hope to repeat it at a later date on a more scientific level.-ED.)
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Annular Aerodynamics (cont.)
The conventional aeroplane is constituted of two basic aero- foils: a wing (which supplies the lift) and a tail (which balances and stabilizes the wing). We know that such an arrangement of the two aerofoil components is by no means the only pos- sible one. The balancing and stabilizing aerofoil (tailplane) need not to be aft of the lifting wing as a tail. It can be arranged anywhere in relation to the wing, e.g., above it, below it, or in front of it.
If the balancing aerofoil is in front of the main wing, the aero- plane is of the tail-first type, and if it is attached to the
Fig. S. Kitchen's doughnut of 1911 .
Fig.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Annular Aerodynamics (cont.)
Fig. 3. -A simple
experiment In annular .ierofolls.
Fig. 4.-Prlnclple or
th• Huth annular-biplane system.
main wing, the tailless aeroplane is created. For all these arrangements, the condition is that, in the case of a wing com- prised of normal (unstable) aerofoil sections, the stabilizing aerofoil exerts a certain leverage in relation to the centre of gravity of the aircraft.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Annular Aerodynamics (cont.)
Another possibility is to combine two lifting wings so that they will stabilize and balance each other. For this purpose, all that is required is that the front wing shall possess, at all inci- dences of flight, a greater effective incidence than the rear wing. In other words, the centre of gravity must be nearer to the leading wing than to the trailing wing, and the whole arrange- ment must be balanced accordingly. In this way, we arrive at the conception of a stable tandem aeroplane.
If we now take such a tandem arrangement and sweep the leading wing back and the trailing wing correspondingly forward so that the tips of both wings merge into each other, we obtain an annular or ring-shaped wing system. Aerodynamically, it is of minor importance if the shape is actually circular or oval, or if triangular or quadrangular shapes constitute the wing. For simplicity's is applied. "annular sake, in all such cases considered here, the term
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Annular Aerodynamics (cont.)
As mentioned, the aerodynamics of such shapes cannot yet be considered as fully established. But it is proved that longi- tudinally stable wing systems can be obtained with such shapes. Some types relying on such wings have shown quite remarkable flying qualities. It is also possible that, with annular wings, the induced drag is less than with conventional wings of equiva- tent aspect ratio.
In common with circular wings, annular wings have the remarkable property that the lift force steadily increases with incidence up to fairly high values without a stall. For all known arrangements the maximum lift seems to occur at incidences exceeding 30 degrees. As such high angles of incidence are not likely to be reached in flight unintentionally, it is obvious why annular wings have become renowned for their good-natured flying characteristics.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Annular Aerodynamics (cont.)
Another property of annular wings (first established by Tilghman Richards) is that the centre of pressure of such wing systems is nearly stationary in flight, or that a travel of the centre of pressure can be obtained which is positively stable until incidences of the order of 18 degrees are reached. In fact, no case of longitudinal instability has ever been reported with an annular wing, although the centre of gravity has often been located dangerously far back.
The first annular-wing aeroplane dates back to 1908. It had little success. Two types were constructed in succession to the designs of a capable German aeronautical engineer, Fritz Huth, who was by profession a teacher at a technical school (Figs. 4 and 6). The second type, which had a less elaborate airscrew drive, flew in May, 1910; it was, however, so devoid of performance, in spite of a 50 b.h.p. engine, that it was soon afterwards discarded as a hopeless proposition.
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flight of Kitchen's models, however, convinced Cedric Lee that an aeroplane of such design would be a success, and late in 1910 he acquired the patents. At the same time, G. Tilghman Richards, who was a qualified aeronautical engineer, became sufficiently interested in the matter to give up a budding engineering bureau in order to join Cedric Lee and to devote his energy to the idea of a "safety" aeroplane.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Britain's First Doughnut (cont.)
Tilghman Richards began with systematic experiments on models and on large gliders. Later, careful wind-tunnel tests (including the observation of the pressure distribution) were made by him in a 2-ft. tunnel he had constructed at East London College and also in tunnels of the National Physical Laboratory. The preparation of the design was, therefore, uncommonly careful for this early period of 1911-1914.
In order to appreciate the intentions for the development, the following quotation from a paper read by Tilghman Richards in about 1912 is illuminating:
The very fact of high lift occurring at small angles means the provision of large area for landing speed resulting in an inefficient attitude of the plane at high speed; and the inherent instability of curved aerofoils means a continual dependence on extraneous controls carried at some distance from the wing by heavy and redundant structure. High lift at small angles is useless, likewise high lift/drag ratio at small angles, and what is required is the reversal of the normal type of lift curve giving little lift at small angles with low value of the lift/drag ratio for landing..
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Britain's First Doughnut (cont.)
Seen from our present state of knowledge and development, and facing the burning problems of personal aircraft for the man in the street, it would seem that this opinion is a very good argument for further experimentation along the lines indicated.
The experience with powered aeroplanes was at first beset with disappointments. Famine Point, Heysham, was apparently not a spot from which aeronautical experimenters could derive any comfort.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Britain's First Doughnut (cont.)
The original Kitchen biplane with a 50 b.h.p. rotary engine was wrecked by a gale, during 1911, before flight tests could be made. After reconstruction some flights were performed with it at Shoreham during 1911-12; yet it never gave any proof of superior qualities. The biplane had ailerons of the biplane original Farman variety between the wings. Very soon the A Sequent arrangement was given in favour of the monoplane. up
shrouded "Secret against Plane or " Doughnut," the experiments being experimental publicity (much against the interests of the monoplane was nicknamed the development). This annular-wing aeroplane (Fig. 7) was equipped with an 80 b.h.p. rotary and test-flown by Gordon England on November 23, 1912, at Shoreham. The flight was remarkable and lucky for the pilot, but unlucky for the precious craft. After having flown a large circuit on the first attempt, the pilot noticed, when coming in to land, that the aeroplane was exceedingly tail-heavy and getting out of control, the elevator being insufficient. At about 150 ft. above the ground the inevitable stall took place; but the pilot managed somehow to drop his mount upside down on to telegraph wires and escaped without personal injury.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Britain's First Doughnut (cont.)
With the reconstructed and improved monoplane many successful flights were made by Gordon England, N. S. Percival
Fig 7. -Cedric Lee Monoplane No. 1 of TIighman Richards, 1912.
Fig. 6 .-Huth annular biplane of 1909.
and Gordon Bell. Finally it came to grief when flown by Cedric Lee himself without previous training. After a good flight he managed to put it into a river.
Another incident happened with a subsequent annular monoplane: the elevator jammed and broke in flight. The aeroplane merely pancaked to the ground, again preserving the health of its pilot, E. C. Gordon England.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Britain's First Doughnut (cont.)
These types in their final form had lateral control effected by differential deflection of the elevators. It was realized that this elevon control was not very effective for lateral manoeuvres, yet the lateral stability of the wing proved so great that the provision of ailerons seemed superfluous. The longitudinal Soperly located. Because of the great inherent fore-and-aft was always satisfactory, once the centre of gravity was stability, a separate elevator was, at one time, located on top of the vertical fin and permitted the fitting of special ailerons. For directional control a vertical rudder was attached to the stern of the fuselage at the trailing edge of the wing. A form of tricycle undercarriage was employed.
In respect of performance, the wind-tunnel tests indicated that a better lift/drag ratio could be expected than with a comparable conventional aeroplane. However, no conclusive evidence for this has, as yet, been presented.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Britain's First Doughnut (cont.)
The third British monoplane of this type also had an 80 b.h.p. rotary engine, but this time it was located aft and, further, drove the airscrew by means of an extension shaft. Unlike its pre- decessors, no dihedral was provided, and because of this the flying qualities were found to have been greatly improved. From early in 1914 until the outbreak of the 1914-18 War this unconventional aeroplane was frequently flown (mostly by Gordon Bell); it was demonstrated before Winston Churchill in the hope of securing orders from the Admiralty.
Altogether, 11,000 miles were flown in about 128 hours, and even people not previously trained as pilots were able to fly it. In May, 1914, two such aeroplanes were being designed for participation in the Gordon-Bennett Race of 1915. When the 1914-1918 War terminated the work, it had clearly grown far beyond the stage of an untried project and could have well been termed a successful experiment with every prospect of becoming a practical proposition.
# The Biolo! of the Flying Sa f cer - I The Story of Low Aspect Ratio Aircraft By A. R. Weyl, A.F.R.Ae.S. (cont.)
## Britain's First Doughnut (cont.)
In 1919-20 Tilghman Richards succeeded in persuading the Air Ministry to place an order for a further experimental aeroplane. But a week after communicating this decision Major-General Bagnall-Wild, the promoter of the idea, retired, and red tape killed an intelligent intention.
It is only fair to record that aeronautical progress has suffered from the failure to have this development continued. As Tilghman Richards stated many years ago:-
There is nothing mysterious about the annular plane. It affords high lift at large angles, has no burble point, and has a good lift/drag ratio for wings with a body. The machine was very fast in flight, for its day, and extremely slow in landing; and there being three distinct regions of lift, one apteroid and two pterygoid on each half-wing, the movement of the centre of pressure was a resultant of three distinct regional movements; and with slight modifications could be made to move in any desired manner without affecting the general efficiency of the plane."
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# The Biology of the Flying Saucer- II
By A. R. Weyl, A.F.R.Ae.S.
In this series of articles the history of low-aspect-ratio aircraft is recounted and technical aspects of their design discussed. leading up to their use for supersonic flight.
(Continued from J>Olt 185, February 13 /rut.) T viously in connection with circu )ar-aerofoil aeroplanes. did HE SECRET-CIRCLE "CONSPIR ACY;• mentioned pre not lack congenially inventive spirits. Early in 1913 an engineer in Dijon. M. Bourgoin. made experiments with an annular wing aeroplane. The tests were unsati sfactory. One feature of this design was the provision made for varying the wing incidence in flight.
More recently, a similar idea was suggested by N. H. Warren
a nd Th. R. Young (Fig. 8). In 1937 they secured a patent (Brit. Pat. Spec. No. 508,022 of December, 1937) for a non stallable monoplane of rhomboidal shape (i.e., leading wing swept bac k and trailing wing swept forwards with the wing lips merged tog ether). This was provided with a conventional tail at 1he stern of a long fuselage and a number of advantage~
# The Biology of the Flying Saucer- II (cont.)
This design, patented in 1937 (Brit. Pat. Spec. No. 508,022), is described as a "non stallable monoplane" with merged wing lips.
Fis. 8. -Project by W arren and Young for a liJht twln
en1 lned two-seater of 90 h.p. (1937). The elevator is
fitted between fin and fuselage. There Is no tailplane.
# The Biology of the Flying Saucer- II (cont.)
were claimed. In 1943 a model for a two-seater fighter with tail turret showed the separate tail omitted; special emphasis was laid on the triangular shape of each wing and the effect of sweep was relied upon. Nothing more has become known since, however, but it is worth noting that the project had been based on sound aerodynamic considerations.
In 1933, the annular wing of the German sculptor Antes created a mild sensation because of the good performance of models made to this conception (Fig. 9).
rhomboidal annular aeroplane of P. Nesbitt Willoughby, a Somewhat peculiar was the aerodynamic conception of the
Key entities:
* P. Nesbitt Willoughby
* Antes (1933)
Fig. 9.-Model of the "annular wing" of Antes, 1933.
qualified aeronautical engineer (Fig. 10 ). Th e Willoughb} Delta Co. of London had taken up the development of th,., idea in 1931 and sufficient means were available to make rather extensive tests.
# The Biology of the Flying Saucer- II (cont.)
The principle is best described as a tandem monoplane with two aerofoil-shaped parts connecting the leading wing with the trailing wing near the tips. The "side wings" had aerofoil shape not only in their longit udinal cross-section (i.e., in the direction of flight). but also laterally. This was considered a characteristic feature and subject to patents. It was claimed that the vortex distribu1ion induce d by such shape gave an unusually h igh aerodynamic efficiency in spite of the small span of the aeroplane. In addition. it was pointed out that the maximum lift was shifted to very high incidences. Moreover. the "side wings" should reduce the drag of engine nacelle, filled underneath them.
# The Biology of the Flying Saucer- II (cont.)
All this was said to be pr oved by extensive wind-tunnel experimentation here a nd abroad. Designs of passenger trans pon aircraft reaching weights of 40,000 lb. were prepared on the basis of model tests made at the National Physical Laboratory and elsewhere. T he results must have been so encouraging that an experimental monoplane with two 125 b.h.p. Menasco engines and weighing 2,540 lb. w as constructed late in 1938 (Fig. 11) . Th is aeroplane flew indeed and was even publicl~ demonstraled (including one-engine fl ight) a1 a Garden Party in May, 1939. Shortly afterwards the experimenter was killed in an uneitplained crash during a fl ight test.
From pressure plots over the "side planes" which have been published, apparently trim changes could be eitpected at various aocidences. These components were thus capable of producing long itudinal inslability and it is not improbable that this and poor control efficiency may have cont ributed to the accident. There was also evidence of a stall at normal incidences. although of a very mild character and with little apparent decrease in the lift c~fficient (which. however, would not exclude the presence of fl uctuating lift forces).
# The Biology of the Flying Saucer- II (cont.)
Fig. 10.-Principle of the Willoughby Delta design.
# The Biology of the Flying Saucer- II (cont.)
Another suggestion for an annular wing was made by L. Peel, in 1944. This, however, was concerned less with the aerodynamic properties of such wing systems than with the arrangement of two engines facing each other with their air- screws, in order to overcome the torque reaction.
A phenomenon of which aerodynamic experimenters were always well aware, but which aircraft designers failed to utilize, was that wind-tunnel tests clearly proved good-natured stalling properties of wings having very small aspect ratios. Yet even in the very early days when centres of gravity were far too far back on the old box-kites, the square shape of tailplanes. then unaccountably in vogue, may have saved the pilot's bacon more than once by its refusal to stall under extreme provocation. Later on science came and proved that a tailplane of "good aspect ratio was more efficient. It was, but it made the stall worse when the centre of gravity happened to be rather aft.
The interesting thing is that aerofoils of circular or square shape were tested in the early days at incidences up to 90 degrees, while on normal aerofoils tests were restricted to rather small incidences only, generally excluding the range of stall.
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Fig. 11.-Willoughby's "Delta 8" experimental
monoplane of 1938.
Thus, an observant student of laboratory tests could have noticed the extraordinary capacity of circular or square shapes to give a very gradual, innocent stall, and that at very high incidences. Yet, apart from a few broad-minded experimenters, no designer drew the conclusion that wings of such shapes promised safety in flight, though it was known from early practical experience that flying in the "second regime," i.e., positively dangerous.
at the stall, was s It is true that spinning-Parker's "Spiral Dive"-was attributed, in those days, to high incidences, and that most of the lightly loaded rectangular wings used at that period rendered the stall relatively innocuous. However, accidental stalling was then, as now, the cause of the majority of all crashes. And the nose dive following inadvertent stalls was well known to be of the most serious consequences.
# The Biology of the Flying Saucer- II (cont.)
Eiffel, Riabouchinsky, Dines, Prandtl, etc., began their laboratory experiments on aerofoils of very small aspect ratio and the results were generously published (how closely secret they would be kept to-day!). Eiffel showed that the ratio of the resultant forces reached maxima for small aspect ratios and that slender wings gave the greatest drag at 90 degrees inci- .dence, whilst disc wings had then the least resistance of all. Riabouchinsky proved that the maximum lift with disc wings was reached at incidences of the order of 40 degrees, whilst with normal aspect ratios (exceeding a value of 4) the maximum lift took place at incidences of 12 to 14 degrees only. Beyond their critical incidence disc wings gave a gradual decrease of the lift force, whereas wings of normal aspect ratio gave a plates in natural wind confirmed this information and that the very abrupt and unsteady one. The tests by Dines on flat proved (by Riabouchinsky). O. Foeppl showed from system- observation applied to cambered aerofoils as well was also atic wind-tunnel tests that a square aerofoil behaves, in respect of its lift curve, in a remarkably different manner from one having an aspect ratio of 1.5, although wall interference and Reynolds Number may have somewhat affected the results of the tests.
# The Biology of the Flying Saucer- II (cont.)
Later, Prandtl was eager to point out that his aerofoil theory did not hold for very small aspect ratios, and that, in fact, the induced drag of disc wings was less than the theory suggested. In spite of this, however, nobody seems to have heeded the possibilities implied and the "Battle of the Aspect Ratios" was decided in favour of slender wings.
To be fair, it must be pointed out that there was one serious
Fig. 12.-Experimenta l Hayden glider, 1925. Span, 19.7 rt. : length, 13·85 rt.; wing area, 173 sq. rt. All-up_ weight, 310 lb. No lateral control.
# The Biology of the Flying Saucer- II (cont.)
argument against disc wings. The best aerofoil sections in use prior to about 1925 had a plain camber which implies travel of the centre of pressure when the incidence varies; the length of such travel is linked up with the wing chord. Hence the change in trim or stability is, with such aerofoil sections, greater with large-chord wings. On this consideration of fore-and-aft stability and control, designers had some justification for their decision against experimenting with disc wings. Yet quite useful aerofoil sections had already been used in flight which had practically no travel of the centre of pressure and hence did not suffer from this disadvantage of the disc wing.
The whole argument, however, lost its importance imme- diately M. M. Munk proved that very efficient aerofoil sections could be designed with a completely (or nearly so) stationary centre of pressure. It is, therefore, right to say that from that time all conditions existed for a practical evolution of disc-wing aeroplanes.
# The Biology of the Flying Saucer- II (cont.)
F. Handley Page converted an aerofoil, leaving an aspect ratio of 6.25, into six square-aerofoil portions by five slots, each parallel to the chord of the wing. By so doing he hoped to have the low drag of a normal wing combined with the high stalling angle of the disc-type wing. Although a very slight improvement was claimed, the principle was that of for the stallinging it too: the induced drag is respon the cake and properties s of the disc wing and you cannot have the benefits of the high drag without suffering its disad- vantages. Moreover, in order to have the effect of the disc wing, the provision of mere slots is insufficient. Marginal vortices need room to deploy.
On the whole, however, the idea proves that at least one practical aircraft designer had realized that there was some- thing in wings of abnormally small aspect ratio.
# The Biology of the Flying Saucer- II (cont.)
There were other, although not quite as well thought out, antecedents of the disc-wing aeroplane. In the first soaring- flight competition on the Rhoen (1920), Friedrich Richter, a burly naval pilot of 20 stone or so, performed on a triplane glider with wings having an individual aspect ratio of far less than three. H. Hayden secured, in 1922, a patent for a rhom- boidal wing with an aspect ratio of nearly unity, claiming for such a shape high lift and good flying qualities.
In 1925 he constructed a glider with a wing having an aspect ratio of only 2.25. The wing was nearly triangular in shape, with its apex leading, and a pronounced wash-out towards the tips (Fig. 12); no lateral controls were fitted. The tailplane with the elevator was fitted underneath the trailing edge at the
Fig. 13.-A French project of G. Abrial, 1929.
# The Biology of the Flying Saucer- II (cont.)
stern of a fuselage. Flying experiments in Styria were said to have proved satisfactory flying qualities.
I
Some early tailless aeroplanes, such as certain experimental types of Rene Arnoux, had rather stub wings and heavily reflexed (i.e., positively stable) aerofoil sections. A 1929 design of G. Abrial showed an aspect ratio of 2.88, with, however, substantial tip discs (which have the effect of increasing the aerodynamic aspect ratio) and wind-tunnel experiments indi- cated a creditable performance (Fig. 13). Russian attempts, in particular the parabola type of Tscheranowsky, too, were experiments with aspect ratios of three and even less (Figs. 14 and 15). Their resemblance in shape to the latest designs of super-sonic aeroplanes is remarkable.
[page 41]
MARCH 5, 1948
281
THE AEROPLANE
Fig. 14. A Russian parabola' glider of 1924.
# The Biology of the Flying Saucer- II (cont.)
## A Modttn Pioneer (cont.)
extensive wind-tunnel investigation and the published reports still form the basis of present development. In places, the results confirm, qualitatively, the experiments made 20 years before. But, as mentioned earlier, these experiments had been practically forgotten.
Zimmermann's target has been the development of a really fool-proof aeroplane for amateur pilots. It is no use hiding the fact that in nearly all accidents in which blame is attributed to an "error of judgment" on the part of the pilot, the aeroplane is actually at fault. The most common causes are the consequences of inadvertent stalling. Once this is completely remedied, the overwhelming majority of accidents will become mere incidents or just fun, and instead of coroners and hospitals, aircraft manufacturers and repair shops will have the benefit.
On such very sound lines (which seem to be generally acknowledged, but still far too often ignored), Zimmermann directed his main attention to the stalling problem. He proved that small variations in the aspect ratio made profound differences and that the shape of the wing tips also had a great influence.
# The Biology of the Flying Saucer- II (cont.)
## A Modttn Pioneer (cont.)
At the same time he confirmed that the induced drag of circular or square wings is by no means as prohibitive as the simple theory of the horseshoe" vortex line would indicate. He also proved that it was simply the induced drag due to the predominant influence of the marginal vortices which brought about the behaviour at high incidences; the idea that the provision of oblique slots might help in this connection proved, however, abortive.
An advantage which Zimmermann's research brought to light was that disc wings gave less profile drag at small incidences (high-speed flight), because of the reduction of the relative thickness of the aerofoil sections. This drag reduction has indeed become one of the main reasons for disc wings being adopted for aeroplanes capable of flying at speeds at which the compressibility of the air needs to be considered. For supersonic flight disc wings seem, at present, to be a necessity. Alternatively, for a given aerofoil thickness ratio, the height available for structure and storage (power plants) is greatest within a disc wing; this makes for light and stiff
Fig. 15.-A parabola' aircraft by B. 1. Tscheranowsky.
# The Biology of the Flying Saucer- II (cont.)
## A Modttn Pioneer (cont.)
wing structures as well as for the possibility of housing every- thing within a wing.
Hence there are very real design reasons for the preference of disc wings, quite apart from the eased accommodation of short-span aeroplanes.
# The Biology of the Flying Saucer- II (cont.)
## Some Remarkable Results
Zimmermann established that the optimum aspect ratio was found between the values of 0.75 and 1.5. These values include both square and circular wing shapes. For a given wing section (Clark Y) the latter gave the highest lift coefficient, 1.85 at 45 degrees incidence, compared with a value of 1.24 at 14 degrees incidence for an aspect ratio of six.
Furthermore, an important result was evidence that at an aspect ratio of unity (square or elliptical wings), and at an aspect ratio of 0.9 (wing with faired tips), no tendency to autorotation could be found. A circular wing (aspect ratio of 1.27) indicated the possibility of autorotation (i.e., spinning) at incidences below that of maximum lift. The possibility of spinning before the actual stall is reached is, indeed, extra- ordinary. All these results refer to tests with the Clark Y aerofoil section.
Less established was the contention that disc wings would give improved lateral and longitudinal stability at low incidences. This seems still to be a moot point of the Flying Saucer.
In Fig. 16, Fig. 17, and Fig. 18 some characteristic results of
# The Biology of the Flying Saucer- II (cont.)
## Some Remarkable Results (cont.)
Fig. 16.-N.A.C.A. tests by C. H. Zimmermann which prove the extraordinary stalling qualities of disc wings.
is seen from Fig. 18 that the difference between the incidence Zimmermann's wind-tunnel experiments of 1932 are given. It of maximum lift and the gliding angle at maximum lift (amax a max) remains fairly independent of aspect ratio, and of the order of 9 to 13 degrees. This would mean that the attitude of the disc-type aeroplane, when flattening out, would not greatly differ from that of conventional aeroplanes. In particular, there would be no need to provide high under- carriages for disc aeroplanes as their gliding path is steep. slots. This is an important difference from wings with leading-edge
# The Biology of the Flying Saucer- II (cont.)
## Some Remarkable Results (cont.)
In practice, however, the landing of disc-wing aeroplanes gives rise to undercarriage problems. As the induced drag increases rapidly with the reduction of flying speed, when the steepens abruptly. This is particularly true of tailless designs, aeroplane flattens out prior to touching-down, the gliding angle and the result is a strong tendency to pancake to the ground as soon as the pilot flattens out. Thus to avoid the necessity of fitting undercarriages able to stand the strain of abnormally high sinking speeds, it has been found practical to land with power on.
For a tailless aeroplane with an aspect ratio of three, M. B. Morgan found that, without flaps, the trimmed gliding angle at 160 m.p.h. was three degrees; it increased to 17 degrees at 126 m.p.h.. while the stalling speed was 115 m.p.h. This pronounced steepening of the gliding angle makes a merger between the aeroplane and the helicopter an attractive proposition.
Another peculiarity of the disc wing established by Zimmermann was its sensitivity to the shape of the wing-tips
NND 927545
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282
MARCH 5, 1948
and pseudo-circular and pseudo-square wings thus exhibit significant d.fferences. This also applies to the ground effect, i.e., the land.ng qualities. The provis.on of oblique nozzle- shaped slots at the tips yielded no useful results. In any case, square-cut tips were found to be a disadvantage, with respect to drag, as well as to other qualities.
Later N.A.C.A. research by F. E. Weick and Robert Saunders referred to aspect ratios of the order of 3 in connection with slotted auxiliary Vevions flaps for the trim of tailless aeroplanes. This constituted the first investigation of what has become known to-day as the "Delta Wing," i.e., the combination of sweep-back with low aspect ratio. Such shapes are of special interest for aeroplanes capable of flying through the trans-sonic region.
## Pancakes á la Zimmermann
# The Biology of the Flying Saucer- II (cont.)
## Pancakes á la Zimmermann (cont.)
The results of Zimmermann's research were so convincing that a number of otherwise quite respectable designers were tempted into experimentation with disc-wing aeroplanes. In accordance with Zimmermann's views, all these designs were intended to be of the safety-first type of privately owned aircraft. This distinguishes the early phase from the more recent interest in Flying Saucers.
In 1934 Farman was stimulated into experimenting with a wing with an aspect ratio of only 1.9. This was seen in his F-1020 monoplane whic was said to have proved very stable a conventional which otherwise had a long fuselage with in flight, but was not further heard of. An experimental parasol monoplane with a completely circular wing, a camber flap in the trailing edge and severely skewed ailerons was tested in the U.S.A. (in 1934), with indifferent results. It was shown in flight in news reels.
# The Biology of the Flying Saucer- II (cont.)
## Pancakes á la Zimmermann (cont.)
At about the same time Raoul J. Hoffmann, of St. Peters- burgh, Florida, an eminent aeronautical engineer of Austrian origin (known as the first to prove-in 1913-that the ratio C/C governs optimum climb and glide with minimum
sinking speed, took up development of the disc-wing aeroplane. Hoffmann's Flying Saucer was a tailless aircraft with an aspect ratio of slightly over 2. The first type was an ultra- light single-seater with 36 b.h.p. Later a side-by-side two-seater with an 85 b.h.p. Cirrus engine was constructed and flew well; the wing tips served as ailerons and the elevators formed part of the trailing edge. The aerofoil sections employed were N.A.C.A. M.6 basically, with N.A.C.A. M.I at the tips. Both are sections designed by M. M. Munk. The former is a reflexed- camber section with a practically stationary centre of pressure; the latter is symmetrical
# The Biology of the Flying Saucer- II (cont.)
## Pancakes á la Zimmermann (cont.)
I
was of welded-steel tube; the wing had three spars. The central structure of the wing, the fuselage and the fin This stability. It seems, however, that the controllability, in little two-seater was stated to fly well and to exhibit very good the cockpit must have been very restricted-a moot point with particular directionally, was not satisfactory. The vision from all these designs. A speed range from 28 m.p.h. to 135 m.p.h. was claimed. The empty weight was given as 900 lb., and the wing loading was 5.5 lb./sq. ft.
One remarkable characteristic observed during the flying tests of Hoffmann's aircraft was that, when coming in to land, just before touching down, the glide flattened. This would the approach was steep: yet prior to the flattening out and
# The Biology of the Flying Saucer- II (cont.)
## Pancakes á la Zimmermann (cont.)
| Aspect Ratio (AR) | CL MAX / CD MIN | Incidence at Max Lift (degrees) | Gliding Angle at Max Lift (degrees) |
| :---------------- | :-------------- | :------------------------------ | :---------------------------------- |
| 0.5 | 70 | 55 | 40 |
| 1 | 105 | 50 | 32 |
| 1.5 | 65 | 44 | 25 |
| 2 | 55 | 36 | 18 |
| 2.5 | 58 | 30 | 15 |
| 3 | 60 | 26 | 14 |
| 3.5 | 65 | 23 | 13.5 |
| 4 | 70 | 21 | 13 |
| 4.5 | 75 | 20 | 13 |
| 5 | 80 | 19.5 | 13 |
| 5.5 | 82 | 19 | 13 |
| 6 | 84 | 19 | 13 |
This chart displays data for the Clark Y Aerofoil Section (NACA Rep No 431) showing the relationship between Aspect Ratio (AR) and the maximum lift coefficient divided by the minimum drag coefficient (CL MAX / CD MIN), incidence at max lift, and gliding angle at max lift. The data suggests that CL MAX / CD MIN peaks at an AR of approximately 1, while incidence and gliding angle at max lift generally decrease with increasing AR.
# The Biology of the Flying Saucer- II (cont.)
## Pancakes á la Zimmermann (cont.)
Fig. 1 17 . -These resulu from Zlmmermann's wind-tunnel tests on disc; wings (1932) clearly show the character!stits of low aspect ratio aerofoils. NND
| Aspect Ratio (b/s) | Coefficient of Resultant Aerodynamic Force (CR) | Optimum Lift/Drag Ratio (L/D) |
|---|---|---|
| 0.7 | ~0.5 | ~6 |
| 0.8 | ~1.5 | ~7 |
| 0.9 | ~2.4 | ~8 |
| 1.0 | ~2.6 | ~9 |
| 1.2 | ~1.9 | ~9.5 |
| 1.5 | ~1.4 | ~10 |
| 2.0 | ~1.3 | ~11 |
| 3.0 | ~1.3 | ~12.5 |
| 4.0 | ~1.3 | ~13 |
| 5.0 | ~1.3 | ~13 |
| 6.0 | ~1.3 | ~21 |
**Chart Title:** Clark Y Aerofoil Section (NACA Zimmermann, Rep. No. 431)
**Key Information:**
* The chart plots the Coefficient of Resultant Aerodynamic Force (CR) and the Optimum Lift/Drag Ratio (L/D) against Aspect Ratio (AR, denoted as b/s) for the Clark Y aerofoil section.
* CR MAX is defined as $(\sqrt{C_L^2 - C_D'})_{\text{max}}$.
* The CR initially rises sharply with increasing aspect ratio, peaks around AR = 1.0, and then decreases to a relatively constant value for higher aspect ratios.
* The Optimum Lift/Drag Ratio generally increases with aspect ratio, showing a significant jump between AR 5.0 and 6.0.
18 .- Furthcr results from Zimmermann's tesu shown here
also indicate the advantages to be gained from disc wings.
# The Biology of the Flying Saucer- II (cont.)
## Pancakes á la Zimmermann (cont.)
seem to contradict the experience referred to above, and it was attributed to a ground effect arising from the rake of the wing-tips. It is indeed reasonable to expect that the presence of the ground would affect the formation of the marginal vortices to an extent which may markedly influence the behaviour of disc wings during take-off and landing. Hoffmann projected a pusher and a twin-engined version, but these types did not materialize.
A further development was the Arup monoplane of R. J. Hoffmann and C. L. Snyder at South Bend, Indiana. The wing shape was very similar. It resembled a semi-circle flying with its straight side as the leading edge; to this wing, ailerons were added as special tips. The aspect ratio practically corresponded to that of the previous Hoffmann types. Again, aerofoils with little centre-of-pressure travel were used.
# The Biology of the Flying Saucer- II (cont.)
## Pancakes á la Zimmermann (cont.)
The latest type had its tailplane and elevator separately located over the wing trailing edge (similar to the Elytro- plane of De Rougé). It seems that the longitudinal control at certain incidences was not satisfactory. The ailerons which formed part of the wing shape and reduced the aspect ratio to a value of 1.75 had a triangular shape and were greatly skewed (taking into account the oblique flow over the wing tips). The engine was a 70 b.h.p. Le Blond radial; a tricycle undercarriage was fitted.
With the pilot alone, a gliding speed of 23.5 m.p.h. was recorded (the wing loading was about 3.3 lb./sq. ft.) and a gliding angle of 21 degrees was measured, with a sinking speed of 12.3 ft. per second, which can be accommodated by a sturdy undercarriage without flattening out of the glide. The maxi- mum speed was 86 m.p.h., and the take-off was stated to require 5 secs. in zero wind.
# The Biology of the Flying Saucer- II (cont.)
## Pancakes á la Zimmermann (cont.)
Several more Arup types seem to have been constructed and flown during 1935. The flying qualities were praised- gliding angles of 1:2.6 being quoted-and the published performance figures sounded extremely good. Yet, for reasons never disclosed, the production stage was not reached and the development ceased abruptly. It is worth noting that Charles Zimmermann himself has taken no part in this development, but he was an interested spectator at demonstration flights with an Arup monoplane at Langley Field.
An Italian "Tortelllno "
At the time . of the Arup development (1934). F. Piana
Canova. an Italian, began to embark on a development for a tajlless aeroplane with a low aspect ratio. In May, 1935, he secured patents for a rhomboidal wing, one diagonal of which coincided with the direction of fl ight. 1 he ailerons were to be located at the lateral apices. elevator and rudder at the rear apex. while the airscrew was in front of the leading apex. Another patent related to bi-convex aerofoils with ducts and control valve~ for the pilot, enabling the latter to neutralize the negative oressure on the forward ventral surface when at negative incidences. The latter patent was, apparently, never submitted to flight experiments.
927545
[page 43]
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19, 1948
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THE AEROPLANE
# The Biology of the Flying Saucer- III
By A. R. Wcyl, A.F.R.Ac.S.
Previous articles In this series appeared In " The Aeroplane" for February 13 and Morch 5
We live Canova projects (described in the previous instal- WIND-TUNNEL TESTS were made in Turin and at Rome of ment of this article). It is interesting to note that the Canova disc-wing types did not make use of reflexed-camber aerofoils. Stability and trim could, therefore, be secured only by an upwards deflection of enlarged elevators.
Early in 1935, an open glider of the Zoegling" type was constructed by a Milan firm and M. A. Garbell made fairly successful flights with it. He reported that the longitudinal stake landings could be performed. (with the enlarged elevator) was good and that The lateral stability characteristic, however, proved deficient, since a
"Dutch-roll" motion was experienced; turns were of question- able steadiness. In this respect, insufficient damping in foll and yaw are mentioned. With winch-launching, this glider reached altitudes of 600 ft.
# The Biology of the Flying Saucer- III (cont.)
On the basis of this design, a light aeroplane was developed and the Italian Government financed the construction of two larger experimental aeroplanes, including one with 130 b.h.p. Gipsy engine. A fatal accident described as "not necessarily reflecting on the technical merits of the design," caused the authorities to change their minds and to terminate this development.
## A Return to Childish Things
Aeroplanes with a long, deep tail affixed to a small-span wing form a development of the low-aspect wing in another direction. Although the overall aspect ratio is low with such an arrangement, the wing system is not that of a disc. It is more akin to primitive kites or, better, to the paper dart of our school days which, as we may be able to remember with some mental effort, exhibited quite remarkable flying qualities and made better use of our school books than we ever expected.
A representative of this aboriginal type is shown in Fig. 19. It crashed during the first tests (which would not seem very surprising in view of the arrangement of engines and airscrews).
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
Another less eccentric arrangement was the French Payen single-seat racer of 1935. engine. type with a 400 This was a daring experimental ΑΠ improved type, this this constructed in 1936. To a very small, conventoplane-was time more reasonable-a 70 b.h.p. light tapered wing, a a large triangular tail was fitted; the wing alone had dihedral, and the overall aspect ratio was about 1.76. No flights have been reported of one of these Payen aeroplanes, but take-off attempts with the second type seem to have suggested that with the small span the torque reaction of the airscrew cannot be adequately dealt with.
Fig. 19 .-An American "F lying Flapjack" with two engines. It crashed while under test (1938).
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
A third de,ign tin 1938) 1hc "Flcchair" \tngle-,cat fil!hlcr rroiect. therefore. incorporalcd two co.1xial coun1cr•rot.11mg ~tf'>Crcws driven by two 1 00 b.h.p. engines mounted in 1andem m the long fuselage. 1 he pilot's cockpit was located at the root of lhe fi n, and a single·lrack undercarriage w.is adopted. 1 here were. however, far too m.iny untried feature unusual design 10 make ii a ~rious proposi1ion. Nothing in th" more has been heard of Payen's cffoA~.
l he ll)Odern ph:ll!e of . 1he Flying Saucer aeroplane i, charactcn1ed by two d1,ttncl development~. One is the hclicop1er-aeroplane, 1he other is the tranb•\onic or buper,on1c aeroplane. H oth have bccome:-unforiunately--cs<;entially military dcvcl _opment~; the proJ_!re~~ is ~cnce bhroudcd in the u~ua I pretcnuou~ \ecrccy Iwhich implies that the potential enemy knows everything) v. hile the work is gravely hampered by elabora1c securi1y precautions.
The helicopter-aeroplane is not a novel idea. Many }Cars ago, for in,iance, Nicola Te~la (famous for his elccirical experiment~ wi1h high-frequency phenomena) bccured a pa1en1 for a taille,~ aeroplane equippe d with a large lifting air~rcw pcrmi11ing a vertical ascent.
In
[page 44]
THE AEROPLANE
338
MARCH 19, 1948
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
Fig. 21. Lift
curves of aerofoils
of different aspect
ratios. (Left)
Wind tunnel
results obtained,
in 1920, at Goet-
tingen, with
Goettingen 389
aerofoil and
square tips. The
absence of stall at
normal incidence
is in evidence, for
aspect ratios up
to a value of two.
(Right) Reducing
the values, by the
Prandtl theory, to
an aspect ratio of
five, shows that
wings of very
small aspect ratio
do not follow the
theory in respect
of the induced-
Incidence correc-
tion.
aeroplane with take-off as helicopter (Brit. Pat. Spec. No.161,948). Earlier still (in 1916), the German, F. Bendemann, a noted research worker on airscrews, conducted a secret development of an aeroplane with a large tilting airscrew capable of rising and descending as a helicopter. The development of this air observation post was later discon- tinued in view of the Austrian helicopter experiments by Th. v. Karman and Petroczy.
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
From his early experiments with lifting airscrews, F. Bendemann found that hovering without forward movement could be achieved-when the power loading of the aircraft was less than about 9 lb./ /b.h.p. With fighter aeroplanes, such low power loadings were already then being approached, and operational experience had indeed shown that certain single- ters could under favourable conditions, be held in attitudes approaching that with a large airscrew, became renowned for this trick in air that of hovering (later the Fokker D.VII combat on the Western Front). Attempts to revive the project at a later date failed, and with the suicide of its promoter (who had gone into the Civil Service), all interest in the development ceased.
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
Charles W. Zimmermann, mentioned earlier as stimulator of the disc wing, approached the conception of the helicopter aeroplane on the basis of his results with low aspect ratio wings. He secured basic patents and constructed during 1934-35, in the cellar of his home, a man-carrying aircraft of his desie airscrews driven by two 25 b.h.p. engines. Due to persistent desi design. This had a wing of only 7-ft. span, with two engine trouble, no flights were made; the little aircraft showed, however, all the essential features of the present types.
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
In 1937 he Aircraft Division of the United Aircraft Corporation granted licence for his patents to the Chance- in Stratfort, Connecticut, and joined this firm for the further development of his ideas. It is possible that the public conception of the mysterious "Flying Saucers" has originated from this development.
a Zimmermann's intention may have been the development of aeroplane for the private owner. The U.S. Navy, however, took an interest in the possibilities of the helicopter- aeroplane, and the work done at present is purely for military purposes. In 1942 a low-powered piloted scale model type V-173 was constructed. This wooden aircraft made many and proved that the ideas underlying the design were
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
principle is that, at high speed and when cruising, the aircraft shall fly as an aeroplane, while for slow speed and hovering it flies as a helicopter. Hence the airscrews are at the same time rotors and must have a rather large diameter. With the V-173 the problem of the prone position for the pilot was studied. and there is reason to believe that the latest types have adopted this feature.
A further step towards the realization of a naval gun-spotter and a fighter for use from aircraft carriers has been the Chance- Vought XF5U-1 single-seater (1946), for which a speed range from 40 m.p.h. landing speed to over 425 m.p.h. has been claimed; in general, it follows the V-173 model. (See p. 185, February 13.)
The aspect ratio of the wing is less than unity. Strictly speaking, however, it is not a genuine tailless aeroplane because of the attachment of a trimming elevator to both sides of the wing. The reason for such excrescences is the need to locate
# The Biology of the Flying Saucer- III (cont.)
## A Return to Childish Things (cont.)
control organs directly in the slipstream of tht: paddle-like airscrew rotor... T he twin rudders, too. are in the slipslfeam. surface and the undercarriage is retractable. Unlike the V-1 73 type, the XF-SU· l h as an all-moving tail
This interesting hybrid h as a modern metal structure. Two Pratt and Whilney R-2000-2 engines Qf 1,350 b.h.p. each (at 2,700 r.p.m.) are mounted within the wing, entirely buried and cooled by forced draught. Water injection for temporarily boosting the oower is one of the engine features.
which allows both rotors to be driven from either of the eogmes A special oroblem was the design of a transmission ~ear - this is a necessity in case of an engine failure. The four· bladed rotors are contra-rotating so that there is no residual torque and are ,eared down to about one-fifth of the engine speed, hence their substanlial diameter. rather high. reaching the order of 40 lb ./s q. ft. The wing loading is
# The Biology of the Flying Saucer- III (cont.)
## The Real Flying Saucer?
Since this experimental type was produced, further progress has been made in the development. It seems that axial-flow gas turbines have been installed, and it is quite possible that a combined propulsion with thermal jet and airscrew rotor is already under test. With this, for slow flight (take-off, climb and landing) the rotors are driven by the gas turbines, while at high speed the rotors are declutched and feathered and pure jet propulsion is used. This would, incidentally,
# The Biology of the Flying Saucer- III (cont.)
## The Real Flying Saucer? (cont.)
| Aerofoil Thickness Ratio (T/C) | Profile Drag Coefficient (C_DPO) - Square Tips | Profile Drag Coefficient (C_DPO) - Rounded Tips |
| :----------------------------- | :----------------------------------------- | :-------------------------------------------- |
| 0.02 | ~0.005 (Flat Plate) | ~0.005 (Flat Plate) |
| 0.04 | ~0.0055 (Flat Plate) | ~0.0055 (Flat Plate) |
| 0.06 | ~0.006 (Flat Plate) | ~0.006 (Flat Plate) |
| 0.08 | ~0.0065 | ~0.0063 |
| 0.12 | ~0.0078 | ~0.0072 |
| 0.16 | ~0.0095 | ~0.0085 |
| 0.20 | ~0.0115 | ~0.0098 |
| 0.24 | ~0.014 | ~0.0112 |
**Key Information:**
* **Chart Title:** Increase of profile drag with section thickness, at zero lift.
* **Data Source:** D.V.L. wind-tunnel tests at low turbulence.
* **Conditions:** NACA 24 sections, Reynolds Number (RN) = 2.7 x 10⁵, Aspect Ratio (AR) = 5.
* **Legend:** Square Tips, Rounded Tips, Flat Plate (baseline).
* **Observation:** Square tips generally result in higher profile drag coefficients than rounded tips for NACA 24 sections at zero lift across varying aerofoil thickness ratios. The drag coefficient increases with aerofoil thickness ratio for both tip shapes.
[page 45]
MARCH 19, 1948
339
THE AEROPLANE
3
# The Biology of the Flying Saucer- III (cont.)
## The Real Flying Saucer? (cont.)
| Thickness Ratio (T/C) | Zero Lift Profile Drag Coefficient (CDPO) | Aerofoil Shape Description |
| :-------------------- | :---------------------------------------- | :------------------------- |
| 0 | 0.01 | Flat Plate (T→0) |
| 0.1 | ~0.02 | Thin aerofoil |
| 0.2 | ~0.03 | Thin aerofoil |
| 0.3 | ~0.05 | Aerofoil |
| 0.4 | ~0.07 | Aerofoil |
| 0.5 | ~0.1 | Aerofoil |
| 0.6 | ~0.14 | Oval-like shape |
| 0.7 | ~0.18 | Oval-like shape |
| 0.8 | ~0.22 | Oval-like shape |
| 0.9 | ~0.26 | Circular shape (T=C) |
| 1.0 | ~0.3 | Circular shape (T=C) |
* Chart Title: Increase of Zero Lift Profile Drag with Thickness Ratio
* Reynolds Number (RNeff): 0.43 x 10⁶
* Data Source: Gerber, Zurich Report No. 6
# The Biology of the Flying Saucer- III (cont.)
## The Real Flying Saucer? (cont.)
of symmetrical aerofoil sectldn. The saving In profile drag Is one of the advantages of disc wings because of their thinner aero~oll section. (Data from Gerber, Zurich Report No . 6). Fig. 23.-lncrease of xero lift profile drag with thickness ratio
explain the extraordinary ability of the reported "Flying Saucers" to be able to fly very fast and high, and also to hover, ascend and descend with practically no forward speed. No other aircraft is known to do that." On the other hand, it is inconceivable that whole squadrons of such unconventional aircraft could already be observed at air exercises. It is rare for military developments to progress as quickly as all that.
For operation with gas turbines a speed range from zero (i.e., hovering flight) to more than 500 m.p.h. has been claimed for the Chance-Vought-Zimmermann helicopter-aeroplane. Technically, there is little reason to doubt that such an amazing speed range can be attained with the combination power plant mentioned.
Incidentally, as there is not as yet a standard term for the combination of an aeroplane with an helicopter, the name "helicoplane" is tentatively suggested.
# The Biology of the Flying Saucer- III (cont.)
## The Real Flying Saucer? (cont.)
The other line of engineering approach which has led to
the disc-wing aeroplane of near-saucer appearance derives
from the trend towards very high flying speeds within the sonic
range of velocities, and in at great altitudes. As now
commonly realized, the sets a speed limit for cony of the gaseous medium
reached when the speed of of flight approaches. sufficiently to the This limit is
velocity at which sound is propagated through the air. This
is a postre flower at altitude. begin to is, to be felt at lower speeds when Compressibility effects velocity" depends solely on the air temperature, and Hence, at altitude.
# The Biology of the Flying Saucer- III (cont.)
## The Real Flying Saucer? (cont.)
air, sets in, the lift is catastrophically When the "shock stall" due to the consibility of the (hence the justification for the expression shock stall"), the drag rises to and the longitudinal stability is grossly impaired by a rapid backwards shift of the aerodynamic centre as well as by fluctuations in the flow at the wing. The experience of phenomena of such distressing nature has given rise to two distinct aims in aeronautical research. One is to delay the onset nset of the phenomena to higher Mach Numbers; the other aim is to find wings which would permit flight within through the trans-sonic regime. The alternative, "within or is still a necessary impediment of definition, since we do not know yet if stable, steady flight will be at all possible within the trans-sonic regime (extending from about 0.8 to 1.2 Mach Number) while there is certainly that beyond this trans-sonic regime, i.e., within the supersonic regime, stable, steady flight can be predicted.
# The Biology of the Flying Saucer- III (cont.)
## The Real Flying Saucer? (cont.)
Two simple means have become known which delay the occurrence of the e "shock stall" until much higher (but still subsonic) flying speeds are attained. One is sweep of the eadin edge of the wing, either as sweep back or as sweep The other a Farnborough discovery of nearly 30 years ago, when high top speeds of airscrews were investi- gated is the adoption of very thin aerofoil sections. The latter leads, as we have pointed out already, straight to aerofoils of low aspect ratio when, for reasons of structural stiffness, a certain wing thickness is required.
In the discussion of the Stalling Characteristics of Tailless Aeroplanes (THE AEROPLANE for April 25, 1947), it was shown that at low speeds, i.e., during take-off and landing, swept-back wings suffer from the disadvantage of instability at the stall. With pronounced sweep-back, of normal aspect ratios exhibit the vice of "self"ept-back wings due to premature tip stall. It was also shown that this vice can be remedied by reducing the aspect ratio, and a curve based on extensive wind-tunnel tests (THE AEROPLANE for July 11, 1947, p. 47, Fig. 8) proved that there is a distinct relation between aspect ratio and angle of sweep-back in this connection.
# The Biology of the Flying Saucer- III (cont.)
## values for the limit of stability at the stall from this araph:- M. B. Morgan has recently communicated the following
# The Biology of the Flying Saucer- III (cont.)
## values for the limit of stability at the stall from this araph:- M. B. Morgan has recently communicated the following (cont.)
| Upper limit of the Angle of Sweep-back (referred<br />to the chord) beyond which self-stall can be<br />expected | Aspect Ratio Required |
|-|-|
| Degrees | |
| 65 | |
| 54 | |
| 46 | |
| | |
| | |
| | |
| | 10 |
# The Biology of the Flying Saucer- III (cont.)
## values for the limit of stability at the stall from this araph:- M. B. Morgan has recently communicated the following (cont.)
It is thus advisable to combine sweep-back with low-aspect ratio when safe stalling is required.
Considerations of high speed lead to a similar combination, since both features tend to delay the shock stall. We have, as a result, the rare case of two quite different aspects of an engineering problem pointing to an identical solution.
The inevitable result has been the development of arrow- Nings," for flight at more or lesseeds disc wings, termed "Delta- which are trespassing into the trans-sonic velocity régime. Another advantage of such wings is that when the shock stall occurs, the backward shift of the centre of pressure is less than with normal wings. The induced drag does not count quantitatively at these high speeds.
Development of such abnormal aeroplane types began in Germany during the War, following the progress accomplished in jet and rocket propulsion since 1937, which had shown that flight at sonic velocity was a practical proposition. A few experimental delta-wing types had been brought to initial flying tests when the War came to a close.
# The Biology of the Flying Saucer- III (cont.)
## values for the limit of stability at the stall from this araph:- M. B. Morgan has recently communicated the following (cont.)
The German development had two distinct aims, resulting in two separate lines of approach. The immediate target neces- sitated by the Allied raids, was the creation of very fast jet fighters or fighter hers which could surpass in speed even the Me Secondly, there was the long-term develop- ment of a a supersonic aeropl capable of flying over very long distances, such as from Europe to America and back, and dropping a bomb or two on the way. It is perhaps not too fantastic to surmise that this development had some connection with the research on atomic bombs and bacteriological warfare instituted by the Hitler Gang.
# The Biology of the Flying Saucer- III (cont.)
## values for the limit of stability at the stall from this araph:- M. B. Morgan has recently communicated the following (cont.)
For the immediate target, orders for interceptor-fighters were placed with enterprising firms, notably with the Horten brothers and Messerschmitt (both pets of the Reichsluftministerium), with the Gotha Works, Henschel, Junkers, Heinkel and Arado (a Government enterprise), etc. In order to facilitate experiments ideas with rather unusual aircraft types and to enable an exchange of sand experiences, special research aerodrome was built at Oranienburg (near Berlin) with all facilities for flight testing (in particular, very long wide runways and workshops for repairs and modifications were provided). This was placed under the command of a capable technician, Lt.-Col. Knemeyer.
# The Biology of the Flying Saucer- III (cont.)
## values for the limit of stability at the stall from this araph:- M. B. Morgan has recently communicated the following (cont.)
of novel prototypes the aerodrome, they were agreeably surprised to discover some On this aerodrome, all the initial and development test the most progressive aircraft ever constructed. It has since had to to be made. When the Russians confected collected with
become certain that they have made intelligent use of this aero- nautical treasure as well as of the technicians collected then and
afterwards. Of the German firms interested in the develop-
been com ment, at least one, the well-known Junkers works at Dessau, has completely transferred to Russia, lock, stock and barrel.
Most of the scientists and designers were urged to volunteer for development work in Russia. Few could afford to refuse.
prototypes at were the followianienburg, at the time According to reliable information, am the Occupati -One Horten tailless delta-wing, which had the been damaged during tests and was undergoing repair; another Horten tailless jet-fighter was just ready for its first tests. There was also the latest version of the Lippisch-Junkers design; an experimental Gotha, and several research gliders. development of the Me 163-C; another advanced Junkers
# The Biology of the Flying Saucer- III (cont.)
## Hitler's Last Secret Weapon
The German long-term development of an aeroplane capable of reaching truly supersonic speeds discarded the gas-turbine jet engine. It was based on the ram-jet or aerodynamic pro- pulsive duct ("Athodyd ")-the simplest engine ever invented.
The ram-jet, a widely discussed invention by the genial Réné Lorin in 1912, had been experimented with in Germany, notably by the Austrian Eugen Saenger (for whom a special laboratory had been built by the German authorities in 1938), by by Otto Pabst, of Focke-Wulf, and by others. Following a suggestion made by Alexander Lippisch (formerly known as an eminent sailplane designer and research worker on tailless aeroplanes), progress had been made with the combustion of solid fuel in ram-jets. Such fuel took the form of solid blocks of specially prepared coal which lined the walls of the duct. This develop- ment had been perfected by the German Research Institute
for Soaring Flight.
(To be continued.)
NND 927545Image notes
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The image displays the word "CONFIDENTIAL" stamped across a beige background. A thick black line is drawn through the word, obscuring the middle letters. There are also two dark, irregular shapes on either side of the text, which appear to be ink blots or smudges.
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The image shows the word "CONFIDENTIAL" stamped across a document, with a thick black line crossing through it. There is also a black circular mark in the lower left corner.
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The image contains the word "CONFIDENTIAL" stamped across it, with a black line drawn through the middle of the word. There is also a black ink blot to the right of the text.
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The image contains the word "CONFIDENTIAL" with a line struck through it, and a black ink stamp or mark to the right of the text.
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The image displays the text "vicinity. NND 927545" and a large, black stamp that reads "CONFIDENTIAL".
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| Direction | Count | |---|---| | NW | 63 | | N | 38 | | NE | 9 | | E | 22 | | SE | 22 | | S | 34 | | SW | 14 | | W | 5 | **Additional Data:** * Circling: 15 * Straight down: 3 * Direction Indefinite: 64 * Direction Not Stated: 61 **Note:** Where an undetermined number of objects were reported, the minimum number of objects are plotted. Same object reported by different people only shown once.
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ONFIDENTIAL
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The image is labeled "CONFIDENTIAL". It shows a photographic print with visible fingerprint patterns. In the upper left corner, there is an object suspended by a line, possibly a parachute or a kite. The right edge of the image features a dark, textured area, likely foliage or a tree line. A small, dark smudge or mark is present on the left side of the print, near the bottom. A small, separate photographic square is attached to the bottom right corner, also containing what appears to be a fingerprint.
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The image shows the word "CONFIDENTIAL" with a black line struck through it.
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the image is of true photo graphic nature, and is not due to imperfections in the emulsion, or lack of development in the sec- tion in question.
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The image is a black and white photograph marked "CONFIDENTIAL." It shows a shadowy, abstract shape on a beige background. There are small "x" marks at some points on the perimeter of the shape. The shape itself appears somewhat irregular and has a lighter, oval-shaped area within it.
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The image shows a large, white, unconventional aircraft wing-like structure lying on the ground. It appears to be made of fabric stretched over a frame. The structure has a smooth, curved surface with some visible seams. In the background, there are some indistinct figures and buildings.
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The image shows a "The Chance Vought XF5U-1" aircraft on the ground. Markings on the tail indicate "NAVY 33958" and "XF5U-1". The text from the surrounding context mentions claims of observed "queer, saucer-shaped aircraft" that could descend vertically and flew fast, linking to the concept of low aspect ratio aircraft.
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Ephibet A
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The image displays engineering schematics of Gustave Koch's "Turbine flying machine" project from 1893/1894.
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The image displays engineering schematics of Gustave Koch's "Turbine flying machine" project from 1893/1894. Key Information: * **Project Name:** Turbine flying machine * **Designer:** Gustave Koch (Munich engineer) * **Year:** 1893/1894 * **Type:** Tailless monoplane of low aspect ratio * **Propulsion:** Ducted fan * **Engine:** 50 h.p. steam engine was planned * **Design Feature:** Intelligent anticipation in the duct design.
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| Shape | Aspect Ratio (A.R.) | |---|---| | Aerofoil (b=6, c=1) | 6 | | Pteroid (b=6, c=1) | 6 | | Square (b=c) | 1 | | Disc (radius r, span b=2r, chord c=2r, Area S=$\pi r^2$) | 1.275 | **Definitions:** * **b**: Span * **c**: Chord * **S**: Aerofoil Area * **Aspect Ratio (A.R.)**: $b^2/S$ **Classification by Aspect Ratio:** * "Pteroid": A.R. > 3 * "Disc": 0.5 ≤ A.R. < 3 * "Apteroid": A.R. ≤ 0.5
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This is an image of an early aircraft, identified as "Kitchen's doughnut of 1911". It features a unique design with two large, circular wings stacked vertically. A propeller is prominently placed at the front, between the wings, suggesting a pusher configuration. The aircraft has a complex internal structure of struts and wires, and rests on a wheeled landing gear. There are two small, rectangular vertical surfaces on the sides of the upper wing.
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This is an image of an early aircraft, identified as "Kitchen's doughnut of 1911". It features a unique design with two large, circular wings stacked vertically. A propeller is prominently placed at the front, between the wings, suggesting a pusher configuration. The aircraft has a complex internal structure of struts and wires, and rests on a wheeled landing gear. There are two small, rectangular vertical surfaces on the sides of the upper wing.
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This image is a diagram of a simple ring with a U-shaped piece attached to its outer edge. The ring appears to be made of two concentric ovals, with the U-shaped piece extending outwards from the larger oval.
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The image displays a diagram illustrating the principle of an "annular aerofoil". It shows a three-dimensional representation of two concentric rings, suggesting a shape with a hollow center and a surrounding outer boundary, which is characteristic of an annular aerofoil.
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This image is a diagram of a simple ring with a U-shaped piece attached to its outer edge. The ring appears to be made of two concentric ovals, with the U-shaped piece extending outwards from the larger oval.
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The image displays a diagram illustrating the principle of an "annular aerofoil". It shows a three-dimensional representation of two concentric rings, suggesting a shape with a hollow center and a surrounding outer boundary, which is characteristic of an annular aerofoil.
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The image displays two views of the aircraft: a side view (top) and a top view (bottom).
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Figure 7 shows the Cedric Lee Monoplane No. 1, built by Highman Richards in 1912. The image displays two views of the aircraft: a side view (top) and a top view (bottom). The monoplane features a single wing, a propeller at the front, and a cockpit area.
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- Cedric Lee Monoplane No. 1 of Tighman Richards, 1912. - Huth annular biplane of 1909.
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-
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The image displays three views of a unique aircraft design: a "light twin" project by Warren and Young.
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* **Top View:** Shows the aircraft from above, revealing a central fuselage with a cockpit and a propeller at the front. Outriggers extend from the sides, each supporting a propeller and a small wing. * **Middle View:** A top-down view of the aircraft's rhomboidal wing shape, with the leading edge swept back and the trailing edge swept forward. Labels indicate "Aileron" on the outer wing sections and "Elevator" near the rear fuselage. The fuselage appears to have two crew seats. * **Side View:** A profile view of the aircraft, showing the fuselage, the rhomboidal wing, a conventional tail assembly with a "Rudder," and landing gear. It also features a front-mounted propeller.
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The image displays three views of a unique aircraft design: a "light twin" project by Warren and Young. * **Top View:** Shows the aircraft from above, revealing a central fuselage with a cockpit and a propeller at the front. Outriggers extend from the sides, each supporting a propeller and a small wing. * **Middle View:** A top-down view of the aircraft's rhomboidal wing shape, with the leading edge swept back and the trailing edge swept forward. Labels indicate "Aileron" on the outer wing sections and "Elevator" near the rear fuselage. The fuselage appears to have two crew seats. * **Side View:** A profile view of the aircraft, showing the fuselage, the rhomboidal wing, a conventional tail assembly with a "Rudder," and landing gear. It also features a front-mounted propeller. This design, patented in 1937 (Brit. Pat. Spec. No. 508,022), is described as a "non stallable monoplane" with merged wing lips.
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The image shows diagrams of a rhomboidal annular aeroplane designed by P. Nesbitt Willoughby and a model of an "annular wing" by Antes from 1933.
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The image shows diagrams of a rhomboidal annular aeroplane designed by P. Nesbitt Willoughby and a model of an "annular wing" by Antes from 1933. Key entities: * P. Nesbitt Willoughby * Antes (1933)
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Fig. 10 illustrates the principle of the Willoughby Delta design, showing cross-sections and airflow patterns. The text discusses trim changes at various incidences and potential contributions to accidents from longitudinal instability and poor control efficiency, with evidence of a mild stall.
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The image displays engineering drawings of Willoughby's "Delta 8" experimental monoplane from 1938. The drawings show top, front, and side views of the aircraft, highlighting its distinctive delta wing shape and twin-engine configuration.
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The image shows the Experimental Hayden glider from 1925. Key specifications: * Span: 19.7 ft * Length: 13.85 ft * Wing area: 173 sq ft * All-up weight: 310 lb * Lateral control: None
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The image shows the Experimental Hayden glider from 1925. Key specifications: * Span: 19.7 ft * Length: 13.85 ft * Wing area: 173 sq ft * All-up weight: 310 lb * Lateral control: None
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The image displays technical drawings of an aircraft. It includes a side view, a top view, a front view, and a cross-section of a wing. The aircraft appears to be a twin-engine design with a central fuselage and a long, slender wing. The text indicates this is a French project by G. Abrial from 1929.
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The image displays technical drawings of an aircraft. It includes a side view, a top view, a front view, and a cross-section of a wing. The aircraft appears to be a twin-engine design with a central fuselage and a long, slender wing. The text indicates this is a French project by G. Abrial from 1929.
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The image shows a "Russian parabola" glider from 1924. Two men stand next to the glider on the ground, which is covered in grass and has a large white surface. Several people are visible in the background, some of whom appear to be near a hill or embankment. Another glider is depicted in flight in the upper portion of the image.
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| Aspect Ratio (AR) | Tip Shape | Data Series | |---|---|---| | 6 | Rectangular | Solid line with circles | | 3.23 | Rectangular | Dashed line with crosses | | 1.74 | Rectangular | Dotted line with triangles | | 1.51 | Rectangular | Dash-dot line | | 1.27 | Circle | Dashed line | | 1.0 | Square | Dotted line | | 0.75 | Rectangular | Dotted line |
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| Aspect Ratio (AR) | CL MAX / CD MIN | Incidence at Max Lift (degrees) | Gliding Angle at Max Lift (degrees) | | :---------------- | :-------------- | :------------------------------ | :---------------------------------- | | 0.5 | 70 | 55 | 40 | | 1 | 105 | 50 | 32 | | 1.5 | 65 | 44 | 25 | | 2 | 55 | 36 | 18 | | 2.5 | 58 | 30 | 15 | | 3 | 60 | 26 | 14 | | 3.5 | 65 | 23 | 13.5 | | 4 | 70 | 21 | 13 | | 4.5 | 75 | 20 | 13 | | 5 | 80 | 19.5 | 13 | | 5.5 | 82 | 19 | 13 | | 6 | 84 | 19 | 13 | This chart displays data for the Clark Y Aerofoil Section (NACA Rep No 431) showing the relationship between Aspect Ratio (AR) and the maximum lift coefficient divided by the minimum drag coefficient (CL MAX / CD MIN), incidence at max lift, and gliding angle at max lift. The data suggests that CL MAX / CD MIN peaks at an AR of approximately 1, while incidence and gliding angle at max lift generally decrease with increasing AR.
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| Aspect Ratio (b/s) | Coefficient of Resultant Aerodynamic Force (CR) | Optimum Lift/Drag Ratio (L/D) | |---|---|---| | 0.7 | ~0.5 | ~6 | | 0.8 | ~1.5 | ~7 | | 0.9 | ~2.4 | ~8 | | 1.0 | ~2.6 | ~9 | | 1.2 | ~1.9 | ~9.5 | | 1.5 | ~1.4 | ~10 | | 2.0 | ~1.3 | ~11 | | 3.0 | ~1.3 | ~12.5 | | 4.0 | ~1.3 | ~13 | | 5.0 | ~1.3 | ~13 | | 6.0 | ~1.3 | ~21 | **Chart Title:** Clark Y Aerofoil Section (NACA Zimmermann, Rep. No. 431) **Key Information:** * The chart plots the Coefficient of Resultant Aerodynamic Force (CR) and the Optimum Lift/Drag Ratio (L/D) against Aspect Ratio (AR, denoted as b/s) for the Clark Y aerofoil section. * CR MAX is defined as $(\sqrt{C_L^2 - C_D'})_{\text{max}}$. * The CR initially rises sharply with increasing aspect ratio, peaks around AR = 1.0, and then decreases to a relatively constant value for higher aspect ratios. * The Optimum Lift/Drag Ratio generally increases with aspect ratio, showing a significant jump between AR 5.0 and 6.0.
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The image shows the French Payen single-seat racer of 1935. It was an experimental aircraft with a tapered wing, a triangular tail, and an aspect ratio of about 1.76. Take-off attempts with a second type suggested issues with torque reaction from the airscrew due to its small span.
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The image shows the French Payen single-seat racer of 1935. It was an experimental aircraft with a tapered wing, a triangular tail, and an aspect ratio of about 1.76. Take-off attempts with a second type suggested issues with torque reaction from the airscrew due to its small span.
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| Aspect Ratio | Legend Symbol | |---|---| | 1 SQUARE WING | □ | | 2 | + | | 3 | △ | | 4 | ● | | 5 | ○ | | 6 | ⊕ | | 7 | ◗ | The image displays two charts showing lift coefficient versus drag coefficient for wings with different aspect ratios. The left chart presents data for aspect ratios from 1 to 7, including a square wing. The right chart compiles results from wind tunnel tests conducted at Goettingen in 1920 on a Goettingen 389 aerofoil with 10% thickness and square wing tips. The right chart's legend correlates symbols with aspect ratios from 1 to 7. The accompanying text notes that the results, when reduced to an aspect ratio of five, indicate that a square aerofoil (aspect ratio of one) does not align with the Prandtl Aerofoil Theory regarding induced drag; its induced drag is lower than predicted by the "horse-shoe vortex" assumption.
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| Angle of Incidence (Degrees) | AR 1 (C_L * 100) | AR 2 (C_L * 100) | AR 3 (C_L * 100) | AR 4 (C_L * 100) | AR 5 (C_L * 100) | AR 6 (C_L * 100) | AR 7 (C_L * 100) | | :--------------------------- | :--------------- | :--------------- | :--------------- | :--------------- | :--------------- | :--------------- | :--------------- | | -10 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | -5 | 18 | 18 | 18 | 18 | 18 | 18 | 18 | | 0 | 34 | 34 | 36 | 36 | 38 | 38 | 38 | | 2 | 40 | 42 | 44 | 44 | 46 | 46 | 46 | | 4 | 50 | 54 | 58 | 58 | 60 | 62 | 62 | | 6 | 60 | 66 | 72 | 72 | 74 | 76 | 78 | | 8 | 70 | 78 | 86 | 86 | 88 | 90 | 92 | | 10 | 80 | 90 | 100 | 100 | 102 | 104 | 106 | | 12 | 90 | 102 | 112 | 114 | 116 | 118 | 120 | | 14 | 100 | 114 | 120 | 122 | 124 | 126 | 128 | | 16 | 106 | 118 | 122 | 124 | 124 | 124 | 124 | | 18 | 112 | 120 | 120 | 120 | 118 | 116 | 114 | | 20 | 116 | 118 | 116 | 114 | 110 | 108 | 106 |
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| Angle of Incidence (Degrees) | Aspect Ratio 1 (Square Wing) | Aspect Ratio 2 | Aspect Ratio 3 | Aspect Ratio 4 | Aspect Ratio 5 | Aspect Ratio 6 | Aspect Ratio 7 | | :--------------------------- | :--------------------------- | :------------- | :------------- | :------------- | :------------- | :------------- | :------------- | | -10 | 0 | -10 | -20 | -20 | -20 | -20 | -20 | | -5 | 20 | -10 | -10 | -10 | -10 | -10 | -10 | | 0 | 20 | 10 | 20 | 10 | 10 | 10 | 10 | | 2 | 30 | 25 | 30 | 25 | 25 | 25 | 25 | | 4 | 40 | 40 | 40 | 40 | 40 | 40 | 40 | | 6 | 50 | 50 | 50 | 50 | 50 | 50 | 50 | | 8 | 60 | 60 | 60 | 60 | 60 | 60 | 60 | | 10 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | | 12 | 80 | 80 | 80 | 80 | 80 | 80 | 80 | | 14 | 90 | 90 | 90 | 90 | 90 | 90 | 90 | | 16 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | | 18 | 110 | 110 | 110 | 110 | 110 | 110 | 110 | | 20 | 120 | 120 | 120 | 120 | 120 | 120 | 120 |
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| Aerofoil Thickness Ratio (T/C) | Profile Drag Coefficient (C_DPO) - Square Tips | Profile Drag Coefficient (C_DPO) - Rounded Tips | | :----------------------------- | :----------------------------------------- | :-------------------------------------------- | | 0.02 | ~0.005 (Flat Plate) | ~0.005 (Flat Plate) | | 0.04 | ~0.0055 (Flat Plate) | ~0.0055 (Flat Plate) | | 0.06 | ~0.006 (Flat Plate) | ~0.006 (Flat Plate) | | 0.08 | ~0.0065 | ~0.0063 | | 0.12 | ~0.0078 | ~0.0072 | | 0.16 | ~0.0095 | ~0.0085 | | 0.20 | ~0.0115 | ~0.0098 | | 0.24 | ~0.014 | ~0.0112 | **Key Information:** * **Chart Title:** Increase of profile drag with section thickness, at zero lift. * **Data Source:** D.V.L. wind-tunnel tests at low turbulence. * **Conditions:** NACA 24 sections, Reynolds Number (RN) = 2.7 x 10⁵, Aspect Ratio (AR) = 5. * **Legend:** Square Tips, Rounded Tips, Flat Plate (baseline). * **Observation:** Square tips generally result in higher profile drag coefficients than rounded tips for NACA 24 sections at zero lift across varying aerofoil thickness ratios. The drag coefficient increases with aerofoil thickness ratio for both tip shapes.
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| Thickness Ratio (T/C) | Zero Lift Profile Drag Coefficient (CDPO) | Aerofoil Shape Description | | :-------------------- | :---------------------------------------- | :------------------------- | | 0 | 0.01 | Flat Plate (T→0) | | 0.1 | ~0.02 | Thin aerofoil | | 0.2 | ~0.03 | Thin aerofoil | | 0.3 | ~0.05 | Aerofoil | | 0.4 | ~0.07 | Aerofoil | | 0.5 | ~0.1 | Aerofoil | | 0.6 | ~0.14 | Oval-like shape | | 0.7 | ~0.18 | Oval-like shape | | 0.8 | ~0.22 | Oval-like shape | | 0.9 | ~0.26 | Circular shape (T=C) | | 1.0 | ~0.3 | Circular shape (T=C) | * Chart Title: Increase of Zero Lift Profile Drag with Thickness Ratio * Reynolds Number (RNeff): 0.43 x 10⁶ * Data Source: Gerber, Zurich Report No. 6
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A scanned archival document page with a cream/yellowed background. The page contains a tabular list of incident records with columns for Incident No., Date, Hour, Location, No. Sighted, and Observed From. The word "CONFIDENTIAL" appears in strikethrough text at both the top and bottom of the page. Two black circular hole-punch marks are visible near the top of the page. At the bottom, below the lower "CONFIDENTIAL" stamp, is the text "NND 927545".
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A scanned archival document page with a cream/off-white background. The page is a tabular list of incident records with columns for Incident No., Observer's Occupation, Maneuvers, and Weather. The word "CONFIDENTIAL" appears at the top center with a strikethrough line through it, flanked by two black ink stamp blots. The same "CONFIDENTIAL" with strikethrough appears at the bottom center, followed by "NND 927545". The table contains typed entries for incident numbers 30b through 40.
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A scanned archival document page with a cream/yellowed background. The page is a tabular list of incident reports with columns for Incident No., Observer's Occupation, Maneuvers, and Weather. The page is marked "CONFIDENTIAL" at both the top and bottom. Two black circular bullet/stamp marks flank the top "CONFIDENTIAL" header. The bottom of the page includes a document control number "NND 927545" beneath the bottom "CONFIDENTIAL" stamp.
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A typed tabular document page from a military/government report, classified as CONFIDENTIAL. The page contains a multi-column table listing incident numbers, observer occupations, maneuvers, and weather conditions for incidents numbered 77 through 100. The header "CONFIDENTIAL" appears at the top center in bold stamped text, and again at the bottom center with the notation "NND 927545". Two small black circular redaction marks appear flanking the top "CONFIDENTIAL" header. The page has a yellowed/aged appearance consistent with a mid-20th century document.
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A scanned archival document page with a cream/off-white background. The page contains a tabular list of incident data with columns for Incident No., Color, Shape, Size, and Sound. The table lists incidents numbered 1, 1a, 1b, 1c, 1d, 1e, 2, 3, 4, 5, 6, 7, 8, 8a, 9, and 10. At the top center of the page is a "CONFIDENTIAL" stamp with a strikethrough line, flanked by two black circular hole-punch marks. The same "CONFIDENTIAL" stamp with strikethrough appears at the bottom center, followed by "NND 927545" beneath it. The text is typed in a monospaced typewriter font.
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A scanned archival document page with a cream/yellowed background. The page contains a typed tabular list of incident observations with four columns: Color, Shape, Size, and Sound. The table covers Incident Numbers 11 through 30. At the top center of the page is a "CONFIDENTIAL" stamp with strikethrough styling, flanked by two black circular bullet points. At the bottom center is another "CONFIDENTIAL" stamp with strikethrough styling, below which appears a document control number. The page has visible aging and scan artifacts.
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A typed tabular document on aged cream/off-white paper. The page contains a multi-column table listing incident observations with columns for Incident No., Color, Shape, Size, and Sound. The table covers incident numbers 30a through 38. The word "CONFIDENTIAL" appears at both the top and bottom of the page, struck through with a horizontal line at the top. Two black circular hole-punch marks flank the top "CONFIDENTIAL" stamp. A declassification or records reference stamp reading "NND 927545" appears at the very bottom center.
Page 17
A typed tabular document on aged cream/off-white paper with the word "CONFIDENTIAL" stamped and struck through at the top center and printed again at the bottom center. The page contains a multi-column table listing incident reports with columns for Incident No., Color, Shape, Size, and Sound. Two black circular hole-punch marks are visible near the top of the page. A reference number "NND 927545" appears at the very bottom.
Page 19
A scanned archival document page on aged cream/off-white paper. The page contains a typed tabular list of incident reports with columns for Incident No., Color, Shape, Size, and Sound. The word "CONFIDENTIAL" appears at the top center with a strikethrough, flanked by two black circular hole-punch marks. The same "CONFIDENTIAL" stamp with strikethrough appears at the bottom center, followed by "NND 927545". The table lists incidents numbered 68 through 83, each with descriptive entries across the four columns. A small bullet point appears near the bottom left of the page.
Page 20
A scanned archival document page with a cream/off-white background. At the top center is the word "CONFIDENTIAL" with a strikethrough line through it, flanked by two black filled circles, indicating a declassified stamp. The page contains a typed table listing incident reports numbered 84 through 100, with four columns: Incident No., Color, Shape, Size, and Sound. Each row contains typewritten entries, many of which read "Not stated." At the bottom center, the word "CONFIDENTIAL" appears again with a strikethrough, followed by the text "NND 927545." The page has a black border around its edges.
Page 21
A scanned archival document page with a cream/yellowed background. The page contains a tabular data layout with six columns listing incident data. The word "CONFIDENTIAL" appears at the top with a strikethrough, flanked by two black circular bullet points. The same "CONFIDENTIAL" stamp with strikethrough appears at the bottom of the page along with a document control number. The table lists incidents numbered 1, 1a, 1b, 1c, 1d, 1e, 2, 3, 4, 5, 6, 7, 8, 8a, 9, 10, and 11, with corresponding data across six columns.
Page 22
A scanned archival document page with a yellowed/cream background. The page contains a tabular data layout listing incident observations with columns for Incident No., Exhaust Trail, Heading, Altitude Ft., Speed, and Effect on Clouds. The word "CONFIDENTIAL" appears at both the top and bottom of the page with strikethrough styling. Two black circular hole-punch marks are visible at the top, flanking the "CONFIDENTIAL" header. The table lists incidents numbered 12 through 24 with varying data entries, many marked "Not stated." A declassification reference number appears at the bottom below the footer "CONFIDENTIAL" marking.
Page 24
A scanned archival document page with a cream/yellow aged paper background. The page is a tabular data sheet listing incident observations with columns for Incident No., Exhaust Trail, Heading, Altitude Ft., Speed, and Effect on Clouds. The word "CONFIDENTIAL" appears at the top center with a strikethrough line through it, flanked by two black circular bullet points. A second "CONFIDENTIAL" stamp appears at the bottom center, also with a strikethrough, accompanied by the notation "NND 927545". The table contains rows for incident numbers 33c through 48, with typed entries in each column.
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A scanned archival document page with a cream/off-white background. The page contains a typed tabular data entry listing incident observations. At the top center and bottom center, the word "CONFIDENTIAL" appears with a strikethrough line through it. Two solid black circular dots flank the top "CONFIDENTIAL" header. The table has six columns with headers and rows of data entries for incident numbers 48a through 56. At the very bottom, below the lower "CONFIDENTIAL" stamp, is a reference number "NND 927545".
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A scanned archival document page with a cream/yellow background. The page contains a tabular data layout listing incident numbers and associated flight/observation characteristics. The word "CONFIDENTIAL" appears as a strikethrough stamp at the top center and again at the bottom center of the page. Two black circular hole punches are visible near the top of the page, flanking the "CONFIDENTIAL" header stamp. A reference number "NND 927545" appears near the bottom center above the lower "CONFIDENTIAL" stamp.
Page 28
A scanned archival document page with a tabular layout listing incident data across six columns. The page has "CONFIDENTIAL" stamped at both the top and bottom, with a strikethrough line through the text at the top. Two black circular hole-punch marks are visible near the top of the page. The table contains entries for Incident Numbers 90 through 100. The lower half of the page is largely blank, with a small arrow symbol near the center-left area. A reference number appears at the bottom center above the lower CONFIDENTIAL stamp.