Releases / 4 / DOW-UAP-D097

Project Sign Progress Report, 1948

File

DOW-UAP-D097

Type

Document, 45 pages

Agency

Department of War

Date

1948

Place

Various

Released

Release 4, July 10, 2026

Open the original on war.gov

The government's description

This file contains an initial report from the Air Materiel Command regarding Project Sign. Project Sign was a 1948-1949 U.S. Air Force program to investigate the nature and origin of unidentified flying objects (UFO). The report details 100 UFO sightings from 1947-1948. The file also contains an article excerpted from “The Aeroplane,” an aviation-focused periodical magazine published between 1911 and 1968, titled “The Biology of the Flying Saucer.”

I

Authority:

•

•

NND927545

HEADQUARTERS
AIR KATERI BL COWAND

MClA/JCB/amb
Wright-Patterson Air Force Base

2DjytAPH 0i948

KCIA

SUBJECT,

Projeot "BIOi" •

TOs

Chief of Staft
United Statea ilr Poree
Waahington 26, D. Co
ATTN s Director ot Int-,lligenoe

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. Ae a reeult of thia letter, Pro~ot HT-304 was a.otiTated on
26 January 1948 and Technical Inatruotion 2185, dated 11 Pebruaiy 1948,
wns published. Present ti.lea on Projeot •s10~• represent a oonaolida­
tion ot reports received directly by Hq, AMC and thoee forwa.rded by
the Direotor ot Intelli gence, USAF.

~. Schedules of activities of lighted 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.
5o The following ia a series of interesting observation• that
were noted when rev19Wing the many incident 0ase11

a. Rigll rate of olimb, aa well aa the apparent a.bi li ty to
remain mot1onleu or hover for a oonBiderable length of tiu o
bo The objeot was described aa being oval, d1ac or 1auoerehaped ~l times.

o. Assooiated sound was preae?It ll tim.H o
d.

Reported sizes have varied from that of a 26-oent pitoe
to 260 feet in diameter, and from the aise or a puraui t plane to tht
ePulk of six B-29 airpl.&nea.
,

NND 927545

t

•

..
AMC
Subject,

2 3 APir 1948

Project "SIG!i"
e.

»umber of objects per aighting,
Objects per sighting
Number of eightioga

l
77

2-6

6-10

over 10

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. Incloaures 2 and 5 are anlargementa of photographt taken of
Incident f40o Inoloaure 4 1s an evaluation of inolosure 2 by thie
Headquarters. Attention 1s iovi ted to the marked aimilari ty between
incloaurea 2 ands. and inoloaure 6. Similarity also exiata between
inclosures 2 and 3 and oonfigur&tiona illustre.ted in inolosure 6.
7. Representatives from tbie Headquartere visited Dr. Ining
Langmuir of the P~sea.rch Laboratories. General Electric Comp&ny.
Schenectady, N. Y. to discuss Project "SIGN". It was the opinion of
this acienti st that prosent a.vai l!I. ble data does not encompass suffi­
ci ent information to enable a positive identific~tion to be ma.deo
Dr. :.a.n&muir was relucts.nt to consider the so-called "flying discsM
as a reality. However, it io be'lieved at this neadquarters that it
is possible to oonstruot a low aspeot ratio airoraft that would d~pli­
oate many of the appearance and performance oharaoteriatics of reported
"flyint discs~. Experts have agreed that thie would be possible through
the intelligent application of boun:lary layer control.

FOR THE COMMANDING GENERAL:

~Me~

J

6 Inols

l.
2.
3.

4.
6.
6.

H. M. ticC~!1.
Co lone1. US&F
Chief ot Intelli gence

Tabulation
Photo
Photo
Eval of Incl 2
Horten Parabola
Biology of I'lying Se.ucor

2

~

NND 927545

/
;
•
CONFIDENTIAL
Incident
No.
Date
Hour
Location
1
g Jul 47
0930
la
g Jnl 47
lb
-
N<>•
Obser,ed
Sighted
P'rom
Muroc ilT Field, M'uroc, Calif.
2
Ground
0930
Muroc,Air Field, Muroc, Cali£.
2
Ground
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
Area 113, Rogers Dry Lake, Muroc
Air Field, Muroc, Calif.
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
~
1305
Portland, Uregon
3
Ground
1305
Portland, Oregon
2004
Roi se, Idaho
ll
4 Jul 47
4 Jul 47
4 Jul 47
4 Jul 47
12
4 Jul 47
1305
Vancouver, Washington
1~
4 Jul 47
1400
14
4 Jul 47
15
l.6
9
10
undetermined wt atated
5
Air
l
r.:.r ound
20-30
Ground
Portland, Oregon
4
Ground
16}0
Portland, Oregon
1
Ground
4 Jul 47
1700
Portland, Oregon
3
Ground
4 Jul 47
ll.00
Mount Jefferson near
4
Ground
9
11r
not stated Seattle, Xashington
Redmon, Oregon
17
2ll. Jun 47
l!S
not stated not stated Toronto, Canada
1
Ground
19
20 Oot 47
1320
Dayton, Ohio
2
Ground
20
20 Oct 47
1100
Xenia, Onio •
l
Ground
1500
14t. Rainier,
a.shington
CONFIDENTIAL
NND 927545

CO~FIDENTIAL e
Incident
No.
Observed
Sighted
From
l~
not stated
No.
Date
dour
Location
21
29 Jun 47
1645
Des Moines, 1owa
22
21 Jwi 47
23
30 Jun 47
1745
Boise, Idaho
1
Ground
24
12 J\111 47
1&5
Weiser, 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
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
30a
7 Jan 4g
1925EST Lockbourne,!B, Columbus., Ohio
l
Oroum
30b
7 Jan 4a
1915EST Lockbourne AB, Columbus, Ohio
l
Ground
30c
7 Jan 4g
1940
Lockbourne il, Columbus, Ohio
1
Ground
31
mid-December early a.m.
l
Ground
1
llr
7 Jan 41! 133&.l'T,OO"' Oocbnan Field, Ky. (south of)
1
Ground
7 Jan~
l4000ST Godman Field, Ky.
1
Ground
7 Jan~
1320CS'J.' · 0odman Field, Ky.
1
33c
7 Jan 4g
J..420 CST 2100 from Oodman Field, Ky.
1
Ground
33d
7 Jan 4a
Gedman Field, Ky.
1
Ground
33e
7 Jan 4g J..430-1600
Godman Field, Ky.
1
Ground
331'
7 Jan~
Godman Field., Ky.
1
~
33g
7 Jan~ 11!54-19()6
lladi.eomi-1.le, Ky.
l ,l -
34
13 Oct 47
05}0
35
12 Nov 41
GQ'l.Jr a.m.
32
32
Ground
about noon Spokane, ·1ashingt,on
Hamon Field, bewfoundland
~
Northern Arizona
1946
not stated
after dark Columbus , Ohio
.
l
,
Ground
~
I.
l4 mi1es north of Dauphin,
J.lanitoba, Canada
ticonderoga at sea (40 miles
south of Cape dlanco, 20 miles
o£f shore)
~
Ground
Boat
\
\
\
I
CONFIDENTIAL
NND 927545

.
DIOIDD'f
Is,
;w.
vu~FIDENTIAL
a...nect
lo.
r,ooat1cm
12111:.
SMaatfd
rra
1
Ground
1
Qro\md
1
Ground
,6
Jot Stated lot Stated !oilt, Idaho
,1
12 oot 47
,s
10 Jun 47
,9
9 Jlll 47
2,,0
Onnd Palla, levtoundland
5
OJ"ound
40
7 Jul 47
1600
Phoenix, Ar11ona
1
Oroun<S
•n
11 JUl 47
lot Stated lltndort J1eld, llatlta
1
Qro,md
42
12 lUl 47
04,0'L
BltndOl't J1eld, Alatll:a
1
Oroun4
43
29 Jun 47
1645
Clll"1on, Ion
18
Oro\lDd
"-5
28 Jun 47
1~,
Roekt1tld, W1■cou1n
7-10
Ground
7-10
Ql"0\1DC2
46
22 Jun 47
1
Ground
47
6 Jul 47 lot Stated 1a1rt1tld-6uilm Air S.le, 01111.
1
Oround
48
7 Jan 48 1920-1955 V1la1Jllton, Ohio
1
Ground
48a
7 Jan ,s
1925
1
Ground
481>
7 Jan 48
1910&ST V11111ngton, Ohio
1
Qrowu1
4&
7 Jan~
19,0
Y1la1Dgton, Ob1o
1
Orcnmd
-84
7 Jan 48 1920-1950 111.111ngton, Ohio
1
ll'ound
~
9 Jan 48
2,00-2,15
J>aJffi 11e , ltntllolq
1
Qroimd
50
10 Jan Ji8
2200
11lcSVood, In Jei-■r,
Oa•• Creek, Ar1■ ona
1200
lot Stated !udape1t, Bung&J"1
I
28 .Jun 47 Afternoon n11no11
.
11,0
Ortent1eld, 1111,
111111.ngton, Ob1o
_,,,.,.•
One at tb11 Orouad
date, PNT1wa17 1 ..oh
27 Deo,, JUI
all at 2000 o 1oloek.
51
'Sept lf
1215
on.ao, oneon
52
,,.
29 Jul 47
1450
53
28 Jan IJ7
1515
54
16 Jan IJ7
55
2:, Jul 47
12-15
Ground
1181111 ton 11eld, Cal1torn1a
2
Oroad
29 1111 •n Atter 1200 llllilton Jield, ca11tarn1a
2
Ground
Lake Jllead, ore1on
5~
Air
22:50
Jorth Sea (50 ail•• troa
1
Air
o,45Z
BIJ'llCffl Pield, ltvtoundland
l
Orolll\d
tbe Dutch coa,t)

-
IAo1c1ent
-CQ~F~DENTIAL
-
us.
56
15a.
6 Jul 47
57
20 lul 47
0015Z
Abou-c! the BUl'aeo (at sea
58
4 Aug 47
BYeJWII
59
14 Se»t 47
60
?fe,
Looat1on
lo.
simaa
Ob1enec!
D:99
1-10
Gi-oan4
1
Boat
Bethel, Alaska
1
Ail"
055ae1T
Reeter Ialand
1
ill'
10 Jul 47
1000
Oor4707, Canac!a
1
OPOUDCS
61
8 Sept 47
22:,0
Salt Lllce Cl tJ, Unb
12
Ground
62
8 Sept 47 22:S0~:S00
Salt Like Cit7, Utah
5 Sl'0'QP8
Ground
2945
one hr. troa 874ne7, Autft11a)
eaoh oan-
ta1D1Dg
:S5~0
01:tJecta.
6:s
29 JuJ. 47
1205
can,on 1em, llontana
64
19 Aug 47
2130
Tv1n Jalll, Idaho
65
2 Jun 47
lot stated Rehoboth Beaoh, Delevan
66
10 Aug 47
2100
67
llJ. Aug 47
1600
68
24 Jun 47
l
Ol'om:ad
A.pprox.
Ol'oun4
55.
1
Ground
811Yer 8pr1.ngt, Ohio
l
Ol'ound
Placemlle, lalitornia
1
Ground
Hot 1tattd
Cuoa4e lountaiJ:aa,
Pwtlan4, 01-egon
6
Ground
69
6 Aug 47 22,0-2245
Ph1l.a4elph1a, Pa.
1
Ol'Ound
70
6 iug 47
Ph1lt4elph1a, Pa.
l
Ol'oand
71
8 Oot 47 lot 1tatecl
Laa Vega■, leYa4a
1
Ol'Ound
72
lot atate4 Jot 1tatec1
Port R1obardl0J1, Alllb
1
Ol"oand
7J
4 Aug 47
Boston (101111e1 n) •••·
2
A1r
74
24 .JW'l 47 App. 1500
•t. A~IU, ftlh!ngton
75
1, Aug 47
saote Rl•er aaix,on, Idabo
l
Ground
76
1:5 Aug 47 Jlornlng
Salaon Du, Ic!aho
2
Ornnd
77
:S 11117 47
1s,~
South BrookYille, Dine
10
Gl'O\IDl2
78
:,o Jun ~7
0910 JIST
Oran4 ClllQ'on, AP1aoaa
2
ill'
79
Apr 47
1100 ES!
R1oba0nd, V11"g1n.1a
1045
1600
1300
lot stated
Ground
1, other■ on Grcnmd
other ooou1ona

coNriBcNTIAL
lno1dent
em..
19,
Looat1op
Jo.
SUhtn
rrw
1
Ground
80
81
7 Jul 47
82
0900
Biokaa Jield, lava11
1
171117 47 2030-2100
0klahOllll CitJ, OklahOJII
1
83
9 hl 47
Bo1 ■t (Between Boise and
hr1d1&n) Idaho
1
z, 84
7 Jul 47 l:500•140<Bft Lakeland, Jlorida
1217
85
1200
°'8tl"Ytd
Ground
5
Cll'ound
Portland, oregon
10
Qromd
86
6 lulJ ~7 lot ■tated
Hollywood, Cal1tonia
l
Qro,md
87
lot ,tated •ot 1tated
HabMrbi1hopehiOJ1 {20 mile,
zx, r tb ) Go rm.any
1
Ground
88
S J.ug if
Atternoon
Baokenaaok, a. J.
l
Ground
89
6 Jul 47
lS45
lanaae City (100 miles west),
l
Air
Ke.neaa
90
29 Jun 47
1500-15:SO
Lae Cruoe ■, !low Mexico
l
Groun4
91
28 Jun 41
2120-2146
Maxwell Pield, Alabama
1
Ground
• 92
lg Jun 47
l2l5-1Sl6
Colorado Springe, Colorado
l
Grcrund
ll Jan 48
l
1650
Harttord, Coumot1cut
l
Air
!O Deo 47
l926PSf
Between Great l'alle, Montana
and Pairfield, Ca!1tornia
l
SO Dec 47
l926PSf
Rosedale, Oalitornia
l
A.ir
SO Deo 47
1926
Lov•look (30 m1lea weat), leTae1&
l
Ground
97
30 Dec 47
1926PST Between Medtord and •t. Chaata,
Oregon
l
A1r
98
2
l(oT 47
Daybreak Houston, Texas
l
Ground
~
Jan 46
lot stated Vasea, 11nland
l
Ground
lot 1tated
l
Ground
95
100
5 Jan 46
Pretaraa&rl, F1nla1'ld

•
Incident
No .
Occupation
Jo1aneuvers
Heatner
1
1st Lt, UJAF
1lone - horizontal fl1gnt
IiOt
la
:,/::,gt,
1"ot stated
.,ot stated
lb
Uninown
t-:et stated
l1 ot stated
le
s/sgt, USAF
Not stated
~!ot stated
ld
Pfc, USAF
Flying in tight circle
!fot stat'3d
le
~fot stated
Horizontal anrl tipht circles
!lot stated
2
:Uaj, USAF
Descended from an intennediate
altitude in an oscillating
fashion almost to the ground,
then started climbing again to
a very high altitude and moved
off slowly in the distance.
Not stated
3
liajor, USAF
Oscillating in a downward twirl-
Not stated
4
Capt, USAF
5
Patr olman, ?ortland Dippi nP, up and down in oscillat-- Not stated
Police Dept.
ing motion
6
Sgt, Oregon Police
7
Patr olman, Por tland Not stated
Police Dept., former
Air Force pilot
Clear with little
or no cloud forma­
tion
Patrolman, Portland Str aight line formation; last
Police Dept. Pri­
disc fluttered very rapidly in
vate pilot
side-way arc
Clear with little
or no cloud for.na­
tion
Patrolman, Portland Strai~ht line fonnation ; last
Police Dept . ?ri­
disc fluttered very rapidly in
vate pilot
side-way- are
Clear with little
or no cloud forma­
tion
Capt., Harbot pilot
Not stated
9
Observer ' s
0::i,v'
stated
ing movement
Falling at three times the rate
?!ot stated
of a parachute
Following each otner
Discs wo'.lld oscillat e and SOl11131-'
times a full disc would be vis~
ibl e, then a half-moon shape,
t hen nothing at all
CUiqfiDE~~TIAL
NND 927545
Clear with little
or no cloud f orma­
tion

Incident
•
•oo
ObaerTer' s
Ocoupad.on
10
Capt, United Airlines Straight-away horizontal flight
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
FUppi 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
about a city block apart. one
behind the other
Cloudless and
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 stated
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 Coe.st Pi lot.
7000 hrs.
Bot stated
lot stated
30
Ca.pt. USAF. Asst
Operations Officer
Climbing and descending vertioally
Solid overcast
30a
VHF/DJ' Operator
Hovering, made three 360
Weather
Ka.neunra
0
turns around one place. Moved
to another position and circled
more. Turns required 30-40 seo.
Diaaeter estimated at 2 miles.
lot stated
Overcast. 1000 ft.

- cor~FIDENTIAL
Incident
loo
Observer's
Occupation
SOb
Traffic Air Controller Bobbing up and down
Overcast
30o
lot a~ated
Climbing and de~oending
High overcast
Profe11or and Bead
or Aero Kn.gineering
Mone
Clear
Lt, USAP
Bone
Overcast
T/Sgt, USAF
Jone
1,it.,Lt, USAF
Bone
High acattered olouds
Visibility unlimited.
High scattered
PFC
lone
lfot stated
33c
Capt, USA1
Kay have been turning
High overcast
with BIS
33d
Capt, Us.Ar
None
32
33a
Maneuvers
Weather
High ecattered,
vi ei bi li ty unlimited
Col, Ky. State Police Kone
Clear
Capt, USAF (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
40
Not stated
3:Sf
Leader •a 869)
a.tVU.
Spiraled downward f'rom 5, 000
to 2,000 f't am then went
upward at a 450 angle
~
d
Cumulus clouds

41 (;J~iadJENTIAL
e
lg,
Obaenv'•
QoogtS,on
1'1
Colonel. USU
. lot atated
42
. .jor, USU
Jo\ atated
4,
Bua Dl'"1"1"
lone
"4
lot 1tated
lone
Jot ltated
IJ5
lot 1tated
lot 1tated
Jot atated
46
Wot 1tat.d
lone
Cloud Nnb.
~7
Captain, usu
lolled frOII 11a. to lid•
Jot ttate4
48
KaJor, USAJ
uoerMlillg 1na deNen41na
lot atawd
48a
!/Bgt
Up and down and 114• w lid•
Cpl.
.lao•Ddtnc and 4eaoendbll
Ine14ent
•entuur•
leeendina and deaoendiag ••'17
np'idl7
Cold and eleu Wi'll
t .. 11attffff 1101141.
r.t&bt aoattezaed
oloudl 1'11:la bait
tOIIU'dl S/1.
Clear nth onr•
eut 1Jl S/1.
48d
lot stated
49
lot stated
lone
lot lbttd
50
En.1.ttlng deatan.er
Approaohil!a llhON traa Ooean then
Pile and tall 1lovly.
lot stated
51
Jot 1tated
lot stated
lot 1tawd
52
Capt, USU, ASS'!. Bon.aonal lett to ri&ht, ri&ht to
Opentiona ottieu 1•tt l i b • cuard 1n an a1Pplane
~
52•
..
laoendlng' and deaeendine
CltlP
inawuotor Pilot fOl'Mtian.
lit Lt. 1n Air
SSll1lar to a ti&hter aiNNtta
aueu.•r• llben u e ~
heaT1.eP 1h1p1.
lot stated
lit Lt, UW, Pilot Boruoul ftJl7 elon tCll'Mtim
lot 1tated
Moaquito Pilot
lot 1tat1d
G<JTernaent Bllplo1•• A)rupt 4atl
Bieh toattered
oond1\1on Tie1\111'7
15 a.ilea.
Il•••ne• t01:1Mr
B-29 Pilot
'rNTel1ng in a detillt't1t are.
CONFIDENTIAL
NND 927545
lot 1tated

Incident
-
110.
Ol>aeryer's
Opomtion
57
Bridge Corustruct1on Bot stated
Clear and dark.
Chiet Pilot-
Not atated
lfot auted
58
IM!¥I8 £1
Yt•Hitr
Plying 1er-,1oe
59
Pilot
Hone
Rot stated
60
Storek:eepel"
lot Stated
Clear at duak
61
Kot stated
lfone
Wot stated
62
lot stated
Not stated
Cloudy
63
Hot stated
BOYel"ing and fluttering, 1'1S1ng
and deecendtng.
Scattered aull
olouda,
64
Executive Direct-
Hor11onal
OnNalt
65
P1lot
lfot stated
Not 1tated
66
Lt. Col, QSC
Sc1ent1t1c
Branch Research
Group.
Horizonal Pl1.g?\t
lfot 1tated
67
Insurance Adjuster None
Clear
68
Prospector
Banking
Cleu
69
Not stated
Hot stated
Not 1tated
70
Insurance Agent
Not stated
Clear
71
Capt. AC Reser-,es
Not stated
Clear
72
A1!S1 0tf1ce1'
Not stated
Cloud to1'118t1on
1oattered abOYe
10000 tt.
73
lavigator
Not stated
5/l.O acattered
cuaulus vith
or ot Housing
Authority.
(Conatellat1on
type ail"cNft)
tops at 10000,
Y111b111ty 10
a11H.
74
Prospector
Standi.nc on edge and banking
1n the clouda.
Mot 1tated
75
Trout Parm Oper.
Rode up and dovn oyer the hills
and hollow ot the canyon tloor.
Mot stated
76
County COlllliaaioner Hot stated
It
NND 927545
Rot stated

In.ctdent
Ob ■erTer'•
Ko,
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 clouds
Y111b111t7 10-12 ailea.
C1T11 Service
A1oendtng slowly
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 a corner and seemed
to roll.
Clear
87
U. S. Army
Descended slowly and then
dropped in a spiral motion,
~ot stated
88
Not stated
Not stated
Not s tated
89
Major, USAF
dot stated
90
Administrative Asst, Not at~ted
Rocket Sonde Section
91
Captain
Trave ling in zig-zag course
Clear
92
Railroad Employees
Climbing, diving and reversal
of direction whioh happened
enry few aeoonds.
Cle ar alld 1unny
Capt, USAP
Shooting toward, the eaat at
45° angle
Not stated
L~ Col, Hq, EPlf
Descending vertically - aeaned
to slow down on nearing the
earth
•ot 1tated
95
C-47 orew
Not sta.ted
Not stated
96
Bot stated
Bot stated
Not stated
97
Airplane crew
Not
stated
tiot &tnted
98
Immigration Service
99
Not stated
lfot stated
Appeared to be spinning in
its descent
Bot atated
?lot stated
81
bplo,ee
10 0
Clear
IL
NND 927545
lot stated
lot stated
Not ata.ted

•
Incident
Sound
llo.
Color
Shape
Size
l
Silnr,-
Not stated
Not
lo
S11Tery
Saucer shaped
lot stated
■om
ld
Retleoted the •un' •
raya
Diac
llot stated
ltot atated
le
Silvery
Diec
•ot stated
None
2
Ahai.num colored
1urface
Thin metallic ob-
stated
Mot atated
la
lb
Puraui t eh1p
Mot stated
jeot, unconventi on al
ah11pe
s
Ye llowiab-llfhite
Spherical
4
lihi'te aluminum
Dietinct oftl out- 50 tt.
J.1m; ta> projectiona on upper sur-
5 - 10 t't, dtaaeter
lot 1tated
face which llight
han been thick
fine or nob1. Tne,e
croaaed each other
at intervals, 1ug­
ge1ting either ro­
tation or oaci lla•
tion ot alow type
5
lot 1tated
Round
.Not 1tated
.llom
6
1'h1 ti ah-brown
Diac
Jllot atated
Jllom
7
J.lumima
Di1e
Mot determined
lone
8
White
Dile
Out ol light be­
!tone
fore det&iled ob­
Hrfttion •d•
Sa
1'hite
Diec
Out of 11 ght be­
ror• detailed ob­
aen-at1on made
Mone
9
Like s hiny ohro­
aium hub cap
Di,o
Mot 1tated
!lot stated
10
.bot 1tated
Thin a.nd a.ooth
Not stated
Jot etated
on bottoa, rough
appea.rinc on top
NND 927545

II~·
,DENTIAL
Inoident
llo.
Color
Shape
She
Sound
11
ffbi t e
Saucer
Jlot stated
~t stated
12
mot atated
Like tlock ot
geese
•ot stated
Low hmmdng
aound
13
Resembled •tallic
llot 1tated
lot 1tated
l ot atated
lt
Lin a new di••
Like a nn dime
Like .. run, di•
lot etated
15
Sil•er
lilot atated
lot atated
llot stated
16
Not stated
stated
lfot auted
17
ltirror bri t ht
Diameter equal to
di atan ce between
outboard enginea
of DC 4:
lot atated
llot s t ated
Not stated
Not
Approximately
circular. no tail
18
Jellow
19
Reflected the 1un
brilliantly
Like ci ga.ra 11uch longer than
wide
Jlot atated
Mom
20
Silnr
Round
About 12 inches in
Mone
diameter
21
Dirty 1'hite
Betwe.n circle
••rt•d aa.uc er
175-2 50 t't. dia:aeter Like electric
12 ft. t hiok
motor or dy­
nmo
Shiny d l nry
Slim body
Quite large
Bri ght and sil•ery
Ral t-circle
Not atated
Not stat ed
Gli&tened in av.n
Too far away to
dotenune ahe.pe
Too far away to
dete nain. ahape
lone
Plying saucer -
lot atated
lot atated
nnd on.l - in­
22
24
25
25
Luminous
DO
26
27
tai l
lot 1tated
lilot etated
Jiot sta'ted
lot atated
Silvery
Citoular in shape
like a wagon whee l
Same apan •• C-54
at 10. 000 rt.
Wot stated
'
28
Not etated
·eomet-11ke
Not stated
29
!lot stated
Almo1t round
lot stated
lot stated
50
White (.light)
dot stated
lot atated
!lone
NND 927545

vbV~r IDENTIAL
lnoident
No.
Color
Sha.pc
Size
Sound
30&
Amber
Round or oval
C-47 airplane
Jliono
!Ob
Bright white to amber Cone-shaped. blunt Rnonnou•
on top and taper­
ing orr toward
bottom
30c
White lligbt)
'
RoWlld
Comparable 'to run-
Bone
way light
31
White
Not stated
lot stated
ltone
52
Amber
Mot stated
tiot stated
!lone
33
Sun flashes on metal Roughly circular
or metallic
At the distance and lone
altitude the object
appeared ~o be the
size of a11Ter dollar
ffll.1 te or luminous.
·rurnod to be more
Unknown - altitude
a.na distance too
Round teudi og to
be conical
great
red aa the aun aet
:53e
Iona
~ot auted
Cone. topped with Jot stated
red
Si lver with shadow
Raindrop
Unlcnown - believed
lone
lJnJcnoa
to be lar~
53d
1'h1. te
Round at time• -
Uneert&in because
cone ~haped
of distance
lone
53e
lfhi. te
Round
l/4: she full moon
33.f
l(atallio
Bot stated
Tremendous
SSg
"lfot stated
Cone
100 ft. high.
43 .rt. acrose
!lone
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
S ft. from point of
lone
38
Reddish with blue
lot stated
background.. Black
with white baokground
SilTer
Ball
NND 927545
view
.Not ate.ted
Mot stated

GONfHltJ'TiAL
Incident
lo,
001or
Shape
~
Soupd
39
Phosphoru1
Ba-shaped diaoa
lot 1tated
lot atate4
~o
Gray
El11pt1cal
20-,0 tt.
Ho11e like Jet
airoratt prior
to 1ts appell" ~
.. No
audible sound
beai-d 11h11e
object va1 1n
Yiev.
"1
Aluaim"-
Round
3 tt. diameter
lot atate4
~2
OH.yilh
Balloon
10 tt diaeter
lot 1tate4
1'-3
Dirty 1'lite
Between a o1.role IJ1d
an oval (ln-.erted
12 tt thiolc and
175-250 tt diameter
llectJ"ie Jlotor
ordynaao
sa~er)
44
lfot atat.d
Jlyina Saueers
(not actually desoribed as being
this shape)
Wot 1tated
none
lJ-5
Hot stated
Rot stated
Hot stated
Bot stated
46
Silvery vh1te Round
Small
lot stated
47
Bo detim.te shape
No detin1te
oolor top
ai(!e l"etleoted 11ght.
C -51'. airplane
lot deterained
due to the noise
ot airplane.
lf.8
Red
Wot stated
Rot stated
IJ.8a
Bright light
48b
Red - ldltn
PllUli.ng Red cone
Ve17 lai-ge cOlll)U'ed Hone
CirculU'-like a •tU'
1n tbe ak7 only luga. to an aeroplane 11,;bt.
ohangi.ne to
red then to
White OI" J"•llow
Hot detel'llintd
Jot 1tated
Red men IIO"fin8 lot atated
then grean and
black to red.
Kot 1tated
lot ■tated
48d
Yellow or tlame Rot 1tated
colored.
lot stated
lot 1tated
49
Not atated
!lot ■ tated
lot stated
Cone
descending
Pencil shaped ob3eot
t

cot~FIDENTIAL
Incident
10.
color
Shape
50
Stated aa
queer 11.&ht.
Referred to aa aauoer
Kot stated
but not stated as being
ot thie detinite shape.
Jfot atated
51
11lver
Bomd
Not stated
•ot •tated
52
llhite. ah1Dy
Circular like a ball
en the bott011 but not
completely round.
15-25 tt Diameter
!lot atated
521
■ilk mite
Bot atated
•ot stated
lone
53
Whit.
C1roular
36 inches diameter
Rot stated
54
Rot atated
Not etated
Rot eta,ed
Not stated
55
RecUab
lot stated
Bot atated
None
56
Dia glow ot
light
Round
2 :tt. d1aaeter
Hone
lfot stated
Kot atated
Larger than C~4
Not stated
57
58
59
Blaok
Incandescent
sound
Si•e
Saucer (not det1n1tel7
1tated •• being tbia
shape)
airplane
Hot stated
Not atated
Hot stated
Diec shaped (the 11'ter
glow •de 1t look like
Barrel Bead, dinner
Wot stated
a oone)
ot a plane tl71,ng
hi&h.
11Cht without
appreciable
blue and no
redd1eh tinae.
60
Plame oolor
plate am the aise
61
White ancS
111Ullinated
Bot stated
Sue ot Pigeons
lfot 1tated
62
YelloV1ah
vhite
Bot stated
811811
Mot stated
Gleuaed and
Shialered
D1so (not actuall7
stated aa being ot
this shape)
, rt. a1aaeter and
ot no great th1ok•
lot stated
neaa.
64
Color 111111ar Kot stated
to eiectr1c 11.&ht.
lot stated
Hot stated
65
lot ltated
Bot stated
15 1nohea diaaeter
lot stated
66
Bright onnge
lot stated
lot atated
Hot stated
Jllutal col01"
top 1urtaoe al1ghtly
IJ.-6 tt 1n le~h
4
:~e :O-l 1nchea
ll'ot stated
67
h1ghl7 po111h- ournd-larger 1n front
ed chi-Ollium.
than 1n the rear .
NND 927545
liOMflDENTIAL

flDENllAL e
•
Incident
Col OJ'
Shape
UU.
sounc1
I
68
Hot stated
D1eo - appeare~ to have
a tail.
30 tt d1aaeter
lone
69
White
lot 1tated
Not stated
Bussing sound.
70
Not stated
Giant til'e cracker
Kot stated
Bu11DI aound
not aa loud
aa a rocket
Ship.
71
Rot 1t1ted
Hot 1t1ted
lot atated
Not stated
72
Silver
Sphere( nt not like
1auoer or diac.
2·3 tt diameter
Rot 1tated
Deep Gold
1111pt1oal
15 tt long 2·3 tt
lot atated
1n length.
74
Bot stated
Tapered lbarpely to a
point in the tront end.
,o tt. diaaettr
Hone
75
Slq blue
Oblong like a broad rill
hat with a low crown.
20 tt. lona am
10 t,. thiolr.
Kade a
Jot 1tated
Hot stated
76
Not stated
av1shiq sound.
Lite the eoho
ot • aotor.
Only oonerete evidence
50•100 tt lfide.
Loud roar
Light gray
e1rou1ar
8 tt. diueter
Bot ■ tated
S1lftl'
Bot atated
Lu•er than a
Not atated
77
Light colored
78
79
or tora appeared on the
lett tangent ot the group.
Pibal balloon When
obaened through a
theodolite.
80
Retleoted vh1te
light.
"Blob 11
81
S11Yer
Large Balloon With silver Large
d11c below it, no attaebing
cables vere noticed.
'
82
Proa t7 ltbi te
Round and tlat
SMll ail"plane
Equal to b\11.k ot
6 eaob, B-29 air·
Hone
lot etated
A 1l1gbt
mahing.
planes td th dia ..
•t•r to tluomeas
ratio ot 10-1.
83
Black
Round
'tVtnt,-.f'ive cent
piece.
lot atated

, .DENTIAL e
Incident
110,
color
Ship,
84
Sb1Jm7
Road
lot ltated
lore~ le11
85
Bot 1tated
Reseabled the D5U•l.
Jot 1tated
lot 1tated
86
Not 1tated
lot atate(!
IOt ltated
lot stated
87
Jot S1t&ted
Bot stated
lot ata.ted
lot atated
88
lot stated
1lying di ec (not ao­
tual ly deaoribed aa
being ot thi• aha.pe)
)lot 1t1.ted
lot atated
Ro\lDd di,o ahaped object
50-60 rt. diameter
bot at&ted
Unitonn with no protu­
Hot atatad
Bot 1tt.t1d
Refleote4
light
SbJ-111.
berano•• euoh •• wing•
of an airplane
92
Light
lot atated
Not stated
looe
Silver
lot ,tated
S-11
lloli ata.ted
Bluish center Appeared to be a di10
·. rl th rod on
its edgH
Reaembled ~ shooting Not etated
at~r; however. obaervera not oertain
94
!ot atatad
lot 1tated
Not stated
Not ,tated
95
Not stated
Not stated
Kot stated
Bot stated
96
Not st:i.ted
Hot etated
Not stated
Not atated
91
Flaah of
Kot atat••
Hot stated
Hot atated
light
98
Bright light
Ahaoat round or perhaps
oval or aauoer-ahaped
2ti-30 miles diametor
lot etated
99
Shining
Brightly ehining object
lot atated
Bot atated
lot atated
!lot stated
100
with long td 1
Wot ,tated
NND 927545

Incident
No.
Exhaust
-
-COt~f\DENTlAL:-
e
Heading
Altitude Ft.
Speed
lffect on Cloud•
t:one
320°
1000-sooo rt.
~00 mph
lot at&ted
le
Not stated
liorthwest
7500-8000
ft.
~50-400 mph
Hot stated
ld
f.ot stated
northwest
7000-8000 f't.
300-400 mph
tlot atatod
le
tlot
stated
tiorthwest
6000 rt.
300-400 mph
~ot stated
2
tot stated
Not at&ted
From very near
the ground to
vory high
Not ste.tod
llot atated
3
Not ata.ted
frost to east
10000- 12000 rt.
200- 225 mph
)lo-r; stated
4
Not stated
North of due
east
Under 20000 ft .
Slower than Hot stated
lllAXimUDl speed
or P- 80
5
Bot stated
Two flying
aoutb - S
flying ea,t
Bo'\ stated.d
Great speed lot atated
6
Not stated
llorthweater ly Undetermined
7
None
Southweat
l
Trail
la.
lb
50000 fto
Terrifie
lot stat.d
Terrific faster than
any object
ever seen
lot stat.cl
by him
8
Rone-
South
40000 tt .
Terrific
lot atated
8a
Jlone
South
40000 rt.
?errifio
Not ,tated
9
Not atated
S01..-th
High over
Globe Mille
Terrific
lot stated
10
!Jone
Northwest
llot stated
Cruised for
Not atated
46 min. at
oonventional
airline apeed
(180 mph) then
rapidly disappeared
11
Not stated
OTer north end lot stated
ot Lake 1'o.shington
CG."f,DENTIAL
NND 927545
llot stated
.ttoi;
a ta. ted

Bo.
E:xhauat
Trail
12
Wot atated
Incident
•
Bee.ding
.lltitude Ft.
Spoed
Effect on Cloud.a
Hot stated
Not atated
lot • ~ d
Hot at&t.<l
Tranlini BO
llot ,te.ted
3 west to
Did not appear
l north Tery high
lot atated
14
F1DENTIAl
lot atated
eaat.
taat they
•ere out ot
eight in eaat
in 2-4 aeoonda
lot atated
JloT1ng slowly
llot atat.d
onr aandy
dletr1ct
15
Iot 1te.ted
l beaded
High
Sot atated
lot atat.d
lot 1tatad
!tot atate4
llot atated
Not 1tated
lot 1tated
Not stated
Hot stated
Very taat
Bot stated
s outhea1t.
2 headed
north1a1t
16
lfot 1tated
.lot atated
17
lot ete.ted
north to IOUth 9500 rt.
about 17<i'
18
Trail atreaa- aeenronr
1ng out beweatend
him like
of Toronto
vapor trail
'beh1m airplane on
misty day
19
Lim alight
Jiot atated
eat to east One 11.ile high
trace ot steam.
Disappeared
1m::nediat•ly.
20
Not atated
Southwest
About 1500 rt.
Faat
llot stated
21
Rot stated
~.N.W.
1200 ft.
About SOO
lot atated
mph
22
S.W. ot S.
Bot stated
7000 tt.
Slower than lot atated
two-motored
U1lY plane
23
Not stated
!lot stated
5000 tt.
lfot ate.ted
lot stated
Cloud-lie
8outheut
Very high
Very tut
Mot atat.d
n.por - retained shape
a.nd persiated
\
tor onr an
hour
NND 927545

Ho.
B.xhaust
Trail
25
Wot stated
26
Incident
•
CONFIDENTIAL e
Heading
Altitude Ft.
Speed
Effect on Clouds
Bast
High
Fast
Not stated
Bluish-black Not sta.ted
Bot stated
llot stated
Cut a clear path
throup cloud•
27
Bluish-black Not stated
15 mi. long
10000 ft.
Fast
Seemed to out
0loud1 open
28
Not stated
Not stated
Did not
Bot stated
Not stated
moveo
Seemed to
go below
horizon
with rotation
of earth
High
10 flying
north; on
reverse course
there were only 7
29
Not stated
30
None (apWest
peared to
ha.ve bluish
streaks out
t'rom aides
Five times
length ot
..'
3000
300-400 mph
Bot ate.ted
Slow
Bot stated
Prom .,ery near
500 mph
g?'Ound to 1000 rt. a,tter 1 t
1200
Jlot stated
atartecl
to le&"ff
object
n.e1n1ty
S0b
bceeding
Small streak 8.8.Wo
trailing object
Bot ate.ted.
600 aph
di!teNn.~ al•
titudea ;
Jfotionlesa
20000-50000 ft.
600-~00 mph Bot 1ta1;ecl • •
Stationary
3000 tt.
Stat1anary
lone
lone visible
Unknolm
nom n.aible Ione
Jfone
210° from
Extremely high
Stationary
!lone
Not stated
Not stated
Bot sta:t;ed
300
Wot stated
Kot atated
SI
White., heavy West to eut
32
lone
33
33a
lot stated
~-~------
"lone
Godman Field
None
Not stated
NND 927545

COhFIDENTIAL
..
Ino14ent
Ezhautt
uutud• rt,
Jo.
Trf1l
lta4w
''°
)lot • ••n
Apptlll'ed to be Very h11b.
''d
?lont
,,.
lone
,,r
lot atated
,,s
Not ■tated
,4
llcmo
,5
81.N• ot
,6
■ tat1onaJ7 .
-
Sptfd
lf(n\ op Cln4f
Appeued lont
to 1M
1tat1ozw-y.
GodMn Jld.
Uncei-tain••PJ higb.
Stationary.Could be seen
throuab oi.ffU
210• t'Poa
25000 tt.
Stationary.lone
15000 tt.
500 IIPh
lot atate4
~ aile•
lOJll)h
lot atated
, Vest to nat
lot stated
Speed ot a lcmt
aeteor ar
tallinC a tar.
IOJ"tbwaterl7
Rot atated
700-900 IIPh lot atated
lot atated
lortbeaat
Jot atated
lot atated Jot atated
,1
lot 1tated
lortheut
aooo-10000 tt.
350111'h
,e
lot 1tated
lfa,t stated
JIOt stated
lot ■ tated lot 1t1t.d
39
Ion•
Bait
,0000 tt.
V0'7 ta1t lot 1tated
40
Kot 1tated
Appeared troa
nOJ'tbeaat.
5000 tt.
~0-600 aph lot 1tated
41
Jot atated
South
lot 1tated
Great
lot 1tated
42
lot ,tated
Borihweat
1500
lOOaph
lot 1tated
4,
lot 1tated
11rat group
S S/£, 8HOnd
1200
,oo mph
Jot 1tat14
lot 1tate4
210• t'Poa
Oodllan Pld .
Approx. 210•
frt• Oodllan Jld.
Southw■ t
tire.
lot ■ tated
group 1/V.
44
lot 1tated
South
lot 1tat1d
hat
45
Jot stated
lot stated
lot stat•d
lot atat•d lot 1tatecS
46
Jot stated
lortbwta tff1,1
1000
, ••tel"
lot 1tated
than an air•
plane.
IJ7
Jot etated
80'1thfllterl7
10000
J'uter 11ml lot 1tate4
•ftT aiNratt
h• ba4 rnr
•••n.
Mot stated
Ga1eous green 5/V llhtn 1t
lett the
a11t.
'f'101D.1 t7 • NND 927545
60111 1uENTIAL
Gained an~ lot stated
101t alt1t•
udt at a
te1"1"1t1o nte.

NTIAL
n
u
?no1dent
Exhauat
10,
n:,11
4aa
ver, tatnt
Att1\Jde Pt.
leaflN
S/1 llhen 1t lett lot 1tate4
emaut trail the Y1t1n1tJ.
llben 1IO'fing.
Gl'eenlah
111st 1hen
deaoending.
lot 1tatect
Spefd
Btteot on ClOlldl
Lett
Jfot stated
T10in1t)'
at nr,
h1gb 1peed.
S/W ldlen it lttt lot 1tated
the TlO 1n1 ty.
lot stated Not stated
210 degree, lllben 15000-20000
1 t lett the Tic -
lot stated Hot stated
1.nity.
~d
lone
Approxblately
1l'011 4000 to
due nat lalen 1t Ter1 hi&b.
lett the T1o1n1ty.
Slow
49
Lon, trail
Vest
Very hi&h
lot atated lot stated
50
Kot stated
Shor•wrd
Rot atated but Slov until Bot stated
OTer land
•aid to be
quite close.
then higher
speed lfbile
ot Doke.
Not stated
leaving.
51
Hot atated
lot 1tated
High
52
Bone
Soutbnrd
8000-10000
Hot stated l ot stated
JCade a P-80 Hot stated
look llke 1t
wu motionleH 1n the
air.
;
52&
Wot stated
120•
6000
Approxiaate- Not stated
lT 150 aph.
53
Bot stated
5~
Bot 1tatecS
120•
6000
285 aph.
Not stated
Borth Sea to
22000
Equal to
Not stated
or greater
lortolk
than • Brit1ab Mosquito .
55
lot 1tated
DE
10000
Rip yel•
Not ■ tated
oc1t7• 1tated
to be taster
than conyent1onal airplane.
56
•ot lt&ted
Soutb saat
2000 tt
CONF1DENTIAL
NND 927545
500-600 mph.Mot atated

•
»ioldent Bxbauat
lo,
m11
57
lo\ 1tated
CO~rlDENTIAL
ltt1s\ on 212'94•
il\1'1\4• ,t.
lltfflPI
DZ <,o• I ot
,o• ott the
llor1son at
true IOJ'th on
bor1.Sonal plane. an ••t1111ted
1,A 1111• rap.
Jli,tl .el.. lot 1tated
001t7, 1tawd toM
taatu t:bUl
• tnoer
\,ullet.
58
lot 1tattd
1/W
1000
510 apb.
lot 1tattd
59
lot attted
,50- later
ohaJll•d to
9500-10000
1000 lmota
lot atat.4
1or.
60
Liabt tlae JPrca 1/1 beadoolor.
1DI Eutwrd.
61
lot 1tated
lorthern
2000-,000
raster than 1'0t 1tated
,ua,.
62
Jot atattd
lot atated
&e-nral
thOUlud tt.
Jl1&b rate
lot 1tattd
lortheaaterly
3000
TrandOUI
Speed.
Jot stated
64
Jot 1tated
lortbeaaterly
lot atated
terr1tlo
Jot 1tattc1
65
lot atattd
Weit to la1t
1000
1000•120011>h lot stated
66
Lone atl'a - lorth to South
tsht '4\itt
1treak 11.llilar to th•
1treak left
by• traoer
bullet.
Low
Required ,-4 lot 1tattd
67
White bail lot 1tattd
500-1000
Tnr1tlo
lot 1tated
68
Wot 1tated
6000
lot 1tated
lot 1tattd
69
Thin 1treaJc South
lot 1tateO
Vff"f t11t.
lot stated
1000-,000
a.oo,oo
1ot 1tated
wot atated
7ooteoo
lot stated
6000
lot 1tated
of 1peed.
1econd1 to
tnffl 70•
an.
of l■Okt.
Southea1terl1
of gl"e7ill\
color.
70
Bitber 1aokt 1B to SV
or conden-
eat1on laatSAI 2 1eoonda.
71
Jilt)' hav•
been IIIOkt
Southeaat then
or npor
net.
t\ll"Jled and vnt
t r • 1nttnae
■i,eed
WI
aiaoet wit•.
NND 927545

Incident
lo.
llxhauat
-
r~eE·~flAl:
i
~hr
iiUuii i
•
ffiil
Bgd1ng
41t1t1»4e Pt,
Sp••4
Vtftt op Qlouf•
72
Iona
South
Below 10000
'flteaendou
Jot 1tated
1,
lone
Ba1terl7
7000
approxillatel1
110• -,netio.
175 IIPh
Rot 1tated
lot stated
•ot 1tated
Jlot ■ tated
Oreata
thd&ft7•
thm, n•r
Witneaaed.
75
lone
Baat to wet
75
lot ,tated
loi atated
76
lot stated
Bot 1tated
4000-6000
lot atated
Jot stated
77
lot stated
Jfortihwat(Trut) •ot stated
600-1200
lot •ta'-4
78
lot stated
8va1&ht down.
Deorna1Jlg tr•
Inaono~nblt lot stated
approi111atelJ
25000.
79
Jot atated
Batt to lfe1t
LIii
t.ban 15000 Jot atated
80
Jone
southeast
Lesa than 500
Kot 1tated
CCIIIPUttd at lot atawd
·1:550 IIPh,
hOWffJI IP•
pelNd to
aOTe "1th
tbt speed
ot • Jet
11.Jlcntt.
81
lot stated
• ortlnreat
6000
lot stated
Bot stated
82
lone
,5t•
10000-18000
Tbree t1M1 lot 1tated
that ot a
Jet atrontt.
8:5
lot 1tated
lot atated
11000
lot stated
lot atated
84
lot atate4
lortbeaat
7500
lot atahd
lot 1tated
85
Bot atated
Borth
8500
35011Ph
lot atated
86
Jfot etated
IOJ1thard
lot stated
lot 1tated
Rot atated
87
lot stated
Not etated
trom 6000
lot stated
lot atated
88
lot stated
lot 1tated
200 yards
110vhig ra,?idly
liot stated
89
llot etated
Eaet
11000
210 mph
JIJot stated
NND 927545
CONFIDENTIAL

11JcnTIAl
Incident
lo.
90
Bxh&uat
Trail
One w1tneH
thought be
Beading
lltitude Ft.
Speed
Ureot on Cloud•
lor'therly
8000-10000
lot atated
lot atated
Diaappear ed
in the aoutb-
Great height
High rate
lot atated
eaw Tapor
traile
91
lot stated
ot apeed
weat
Jlot stated
95
W.at
Abon 1000
Oreat a pffd
lot • tated
Dropped troa
sight on north
aide of •t.
Tom near
Holyoke. MaH.
Iot atated
Ver, high
lot atatecl
Telooity
Green and
Deaoending Ter- Prom lSOOO
blue tleaea tioally
'fery high
Se..-eral color•
ot r1..... -
Very high
Saatwa.rd
rate or
red and green
liot atated
rate ot
apeed
Jlot
atated
apeed
predomin ating
96
lot stated
Bot stated
1200-1500
lot atated
Hot atatecl
97
Wot stated
1'ot atated
Mot stated
!lot etated
Mot atated
98
lot stated
Jlot atated
lot at&ted
lot a tated
lot stated
99
Mot atated
lreat to eaat
tilot stated
lot stated
llot atated
100
Grey streaks Borth to aouth
were left in
eky
lot atated
.llot stated
lot atated
.
NND 927545

lfOtE:

Inc1dent f 18
It has now been d•tini t•ly determined that both tho photograph
and story were t. hou:, perpetrated tor publioity e.nd aooey.

Incident #8•
The peraon malting t he report on thil 1nc1deat was detsrainod to
be &n excitable person, ••r/ talkt.tive, and poaseaaing a.n ex­
a ggerated.. iugination and 1nol1ned to iJlpreaa people with his
continuous uhatter.

NND 927545

CONFIDENTIAL
REPORTED DIRECTIOIS OF PLIGHT
D
5
I
2Z
34
Circling 16
Straight down 5
Directi on Indefinite 64
Direction lot Stated 61
s
• 1'he re an undetermined number ot ob­
jecta ware reported the minimum number
of object& are pl ottedo Same object
reported by di !'teren t p,ople only
shown oncto
NND 927545
CONFIDENTIAL

eCONFIDENTIAL

•

Identit1c&tlon ot Subjeot llatter (a, per ••Pl•)
IIOU

11CIT

19 Feb 48

l

l. Reterenoe 1a ade to th• £11&1 tann b7 llr. Rhoad•• (In.oident f,40) which
••re tonrarded tor exuination. Tb• tollcnriq data ••r• dtri·Hd. froa a atucly ot
the 1peciaen1

a. It ia oonoludecl that th• me• ii of tne pbotogn.phio m.ture, and
1• not due to 1~rteotion1 in th• nul.S.011. or lack o1 deTel opaent in the ■ to­
tion in quHtion. Th• im.c• •xhibit1 a "tt.11" indicating th• pn,per t)'~ ot
di1to·rtion due to the tne ot 1hutter u1ed, tht apt.cl of the o'bj•ot and tht
fixed •peed. of the abutter. Thll trailing ott oontona, to th• g.ntral intor••
tS.oD gi T~ 1n th• report.

•••n

l>. Th• nport 1tatH th• objeot na
a.1- approxiat•ly 2000 t••t
at tho t i • ot expoaure. !he obaerHl" allO report, bein& abl• to Ht oltarl1
t. oanow of •nolo1v•. !h• Tiaual aoui ty ot an aTerag• perao!lf'woulcl allow tor
thi• peroeptioa, bu't oH•te:l Illy not auoh t'\ll'ther •• 'the 1ubjeot Md low fl nal
ooutraat, being cn.y againat a C!'&T •~• It•• ou e1tabl1ah the 41,teoe troe
o&aora ~o 1ubjeot, •• Will h&Te quntlty ,fl. !he report 1tate1 tha.t a 820 oaatrt.
n.1 u,.ct, in4ioat1ng Hnn.l po111Mlli1••• ti.not tht 620 ia ooa111cle.tur• for the
•pe>oli~ a.114 width ot the til.a •• aay h&Ye mptiT•I 2t' X 2t", 2f X ~ a.n4
2-t x 4f'. The aaapl• aubaitte4 ha.cl been out and it wa1 not po11ible to Ht&blilh
the 1xaot traat dse. !be 2t x 2f' Iii• waa rul•d out, 1-anrc 2¼ x st" a.nd
i¼ x ~ . It 1 t ftre th• ro,...r, them. the tooal leqtii ot the 101 would be •••
an4 uelisg 2000 teet ... the approid.u.te aubj•ot diatanoe and the lagt dH at
1/M•, .. ban an app,onaat• ••se ot '4 t••• a, the cllagonal of the objeot.
low 1t wa ohoo ■• the latter n.lue ot a• tor t.,eal length, •• h&Te an approxi•
•te T&lue ot' &&• tor th• cliagon&l. Poln-t:1 ot meaauNaent are 1ndioated troa .

x to x on lxhibit ••••

CONFIDENTIAL
NND 927545

THE AEROPLAtlE

18S

FEBRUARY 13, 194&

I

#

The Biolo!

of the Flying Saf cer- I

The Story of Low Aspect Ratio Aircraft
By A. R. Weyl, A.F.R.Ae.S.

the

o ther hand. the U.S. Air Force considered the matter seriQU\

tained, indeed. tha t they had seen ,quadron\ of , uch mysterious
ob{"ccts; others described vividly how these celestial saucers v.ere
ab e 10 descend vertically. All agreed on the \aucer-hl.e , hapc.
Sceptics considered that, for non-aerona utical people ltv1ng
far from the former playaround s o f V . I. V.2, a nd all the rest
of H itler's "civilizator y • practices. flying saucer<; might indeed
constitute phenomena of threatening aspect, from their experi­
ence of domestic disagreemen ts. Doctors, however. hastened to
assure the World that saucer-shap ed or lenticular objects could
well be nothing more than specks in the lenses of the eyes of the
observers- the so-called m11sae 1·0/ames associated with high
blood pressure. Teetotallers blamed the sorry consequence.. o f
imbibing intoxicating liquors for the observation s. On the

In the meantime. the occurrence of Flying Saucer\ ha..
to be new\. P resuma bly. the~ have all landed. [A new crop
wa<; reported in Tur AER0PLANF for J anuary 16 la~t under the
heading •• Tuppence Coloured." -Eo.]
Aerooaudc-al Aotlquities and lniquititt
As a matter of fact. saucer-\hap ed aeropla ne.. are not quite
as new as some people have tried to mal.e out. (Fig. I.) Quite
a number of a1rernft have been constructed and nown with
wi11gs of the ring or disc type which could well have been mis­
ta ken for saucers. hat-brims. ~pades, doughnut~. diamonds.
Greek letter,. pancal.e\, nat fhh. geometrical symbols. d inner
plates, and other entirely non-aeronau tical commoditie s.
Moreover. it is qu ite true. .and not even a minor secret, that,
at present. aeronautica l engineers are paying increased a ttention
to s uch queer wing shapes: disc wings. for instance. permit
ceriain disadvantag es of conventiona l wing\ to be overcome. It
1s even thought that such shares have been neglected too long
1 he blame for rheir neglect can be ascribed to the doctrine
o f the induced drng. When the Lanche..ter-Pranc.ltJ aerofoil
theory became recoi,1nized nearly 30 }ears ago, and \\hen the
!>a1lplane movement proved that slender wings were a necessity
fo r soaring. designe r, began striving a fter .. good .. aspect ratios.
The theory blinded their eye~ agains, the poss1bili11es of other
than convenriona l wings. T hi~. hO\\Cver. was not the fault C"f
the theory.,\\ Prandtl soon sho\\ ed its restrictions.
We have now come 10 reconsider the matter of wing shape
in an objective way. as it is quite possible that aircraft design
is approaching a cul-de-sac ~o long as it retains it~ bias in

EVERAL MONTHS AGO peo ple o n both side.. of
enough to warrant inve..tigation s into the incidenis which had
S
Atlantic rushed into print wnh claims of having ob~erved
been reported.
queer saucer-shap ed aircraft which new very fast . Some main­
ceased

- - 6 - - - -~

1

==~
Apttro.l

L-- .I_
_1_ _ ____,, - r . : - - i , (b
_°'
_ _ __ _,_ ' _'°'

I

c 6)

OCl5S • stCTIO!'I

Fig. 1.-" Turbine flying machine" (project) of the Munich
engineer Gustave Koch, 189311894. Tailless monoplane of
low aspect ratio. propelled by a ducted fan. A SO h.p.
steim engine wu deemed sufficient for th is flying motor
car. The design of the duct shows intelligent anticipation.

Fig. 2 (Right).- Definitlon of the aspect ratio of an aerofoil.
The arrows signify the direction of the air flow against the
wing. The terms pteroid (feather-like) and apterold have
been introduced by F. W . Lanchester.

NND 927545

t

,pa"

C

chor4

\

)(•-,lod a,u

SquHC'

...~
L

\

,

...._______.

I- b , __j

ttt

AR • 0-1

l t t

\

I

THE AEROPLANE

186

C..HlUr of the "well-tried " convention,
.. normal " wings.
For the c reasons. a study of. the hi\lory of the u'IC of low
asp,.-ct. rat,o) m wing de:.11n will be of interest.
Sp1ruually, the fathers of uch acronauucal exhibits were
Ens!"hmen. 1 hey were people of good reputation ttnd by
no _me.ins suspect o( aerodynamic perversion.
F. W. Lanchcstcr was undoubtedlf the first acrodynamici ,t
to g,~e thought to aeroplane winis ot circular or squ.irc ,hapc.
lo ht) bool.. publl\hcd m 1907, he referred c'<prcssivcly 10 ~uch
"aptcrold" wmii hnpc~ {F1a. 2) i,nd advanced the view tha t
Nc11.ton's law wa, valid for these. 1he correctncs; of th i~
vie\\ wa~ c~pcrimentally proved 30 ~cars later.
In a prev1ou\ article on " Stalling Characteristic s of Taille-.s
Aeropl.rne~ •• ( lttE AFROl'LANI:. for August IS. 1947), tl,e early
mtcrc-.t tal..cn by F. <i:iow Sir Frederick) Handley Pa~e m the
stalling quahucs of wmgs of low aspect rauo was mentioned.
He showed, 10 a pap~r read an April. 1911. that marginal vortices
and pressurc-equa lmng flow a round the tips were respon~iblc
for the delay of flow separation which h.id been obmved at
high incidence).
He stated. in this connection:-•· . .. With planes of high
aspect ratio _(I.e.. with slender wings of normal span chord
rnllo), \here " not the same facility for the " feedmg m " of
f_rcsh air at the plane sides (i.e .. nt the wing tips) 10 act as a
l~nk between the plane and the live stream. and therefore the
live stream leaves the plane's b11ck at .in earlier st11i;e than in
the ca,e of the plane of lower aspect ratio. . . ." He then
sho11.,ed_ some experimental evidence for the delay of flow
separauon with decrease of the aspect ratio and for the greater
maximum lift of such wing~.
. When Lanches.t cr published his bool.., man was ju~t begin­
nma to_spre~d his wmgs. and in order 10 fly with a minimum
ellpend1ture m power, wini:s of fair aspect ratio were a neccs­
s11y. Neverthele\s, there were a few early aeroplanes. notably
the little :· Demo1~lle •• monoplane o f Santos Dumont (190919 !0l, which had an aspect ratio of only 2 and proved to be
qu Ile \Ucces,ful.
One o( the earlie~t attempts at a genuine •· apteroid" 11cro­
plane was an experiment by a German architect, Flick-Remig
( 1910). It had a span of 7 j ft .. and performed in hops only.
Annular Aerodynamks
A ,1mple experiment with ~ome paper and a pair of sci,sor;
shows that the ~inl..ing speed of a circular disc loaded with a
paper clip is decreased when a hole of suff1e1ent d iameter is cut
out in the centre (Fig. 3). This justifies the development from
the circular d1-.c wmt; to the annular aerofoil. The theory of
the phenomenon i~ still somewhat obscure.
(Having tried thl\ experime01. we can confirm that the char­
acteristics of an annular aerofoil are certainly very d ifferent
from those of the plain d1-.c aerofoil. Our own experiment,
11.cre admittedly somewhat lim1ted in scope and we were unable
!O form more than an imprc~10n of the relauve sinking ,peed,:
II did, howev~r. arpcar to be le,~ with the annular aerofoil. Our
mam conclu\lon, w•!re that cutting a 2.25-in. diameter hole in
a .5 37S-in. diameter disc. resulted in a much flatt.e r glide; the
,tall 11.,1, not ,o abrupt. and the stability in the glide wa,
1mpm,cd. We were so fascinated with the e>tperiment th.it we
hope to repeat u ,U a later date on a more ..c:1entific levcl.- Eo.)
fhe conven11onal aeroplJne " constituted of two ba\ic aero­
frnh: a "ing (,, h1ch ,uppl1e~ the lift) and ri tail (,, hich balances
and ~tabilize~ the wing). We I.now that \Uch a n arrangement
o.f the 111.0 aerofoil compnnenh i, by no mean, the only pos­
\tblc one. The balancing .ind st11b1lmng aerofoil (tailplane)
need not to be aft of the lifting wing a, a tail. It can be
arranged anywhere 1n relation to the wing. e.g .. above It, belo11.
it. o r in front of it.
If the balancing aerofoil i, in front o f the main win~. the aero­
plane i~ of the tail-first type. and if it i, attached to the

Fig. S. Kitchen's doughnut of 1911 .

FEBRUARY 13, 1948

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 wina com­
pmed of normal (unstable) aerofoil ~lions. the stabilizin&
aerofoil exens a certain leverage in relation to the centre of
gravity of the aircraft.
Another possibility is to combine two lifting winas 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
dence, of.flight, a greater effective incidence than the rear wiog.
In other words. the centre of gravity must be nearer to the
le.iding wing than to the traili9g wing, and the whole arrange­
ment must be balanced accordmgly. 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 wina correspondingly forward
so that the tips of both wings merge into each other, we obtain
an annular or ring-shaped wing system. Aerodynamica lly, it is
of minor importance if the shape is actually circular or oval,
or 1f triangular or quadrangular sha pes con,titute the wing. For
,implicity's ..ake, in all such cases considered here, the term
.. annular" 1, appl ied.
As mentioned, the aerodynamics of such shapes cannot yet
be considered as fully established. But it i, proved that longi­
tudinally stable wing systems can be obtnined with such shapes.
Some type~ relying on such wings have shown quite remarkable
llying qualiue~. It is also pos,ible that, with annular wings. the
induced drai; i, less than with conventional wings of equiva­
lent aspect ratio.
In common with circular wing,. annular wings have the
remarl..able property that the lift force ,teadily increases with
incidence up to fairly high values without a stall. For all
I.no" n arrangements the maximum lift seem, 10 occur at
incidences exceeding 30 degree,. A, ,uch h igh angle~ of
incidence are not likely 10 be reached an flight unintentionall y.
It 1s obv1ou, "hy annular wings have become renowned for
their good-natured flying charac1eri,1il:,.
Another property of annular wings (first establi,hed by
Tilghman Richard,) i, that the centre of pre,sure of ,uch wing
,y,tcm, i, nearly stationary in flight , or that a travel o f the
centre of pre,wre can be obtained which i, po,itively stable
unul incidences o f the order of 18 degree are reached. In
fact. no case of longitudmal in,tabihty ha, ever been reponcd
w11h an annular wing. although the centre of gravity has often
been located d:ingerou,ly far back.
The fi~t annular-wing aeroplane dates bacl.. 10 1908. It
h,1d little succe\\. Two type, 11.ere con~tructed m ,ucces\ion
tu the de,1gns of a capable German aeronautical engineer, Fritz
Huth. who "as by profe\\1on a teacher at a technical ,;chool
( f-tg,. 4 and 61. The ,econd type. which had a less elaborate
a1r,crcw drive. flew in May. 1910: it wa,. however. ,o devoid
of performance. in spite of a SO b.h.p. engine. that it was soon
,1f1erv.ards d1..carded as a hopeless proposition.

Britain'~ Fir..1 Doughnut
The Bri11,h concepuon of the idea has been for more
,ucccs,ful. A, it i, cun,1i1u1ed, until now. the best tried
reprc,cntativc. it~ hi,1ory may be given somewhat more
c,1cn,1vcly.
Ihe ori~mal idea for an annular-wing aeroplane came from
(,. A K itchen. m about 1910; he con,tructed a b1pl.1ne with
rini:-,haped wmg,, but made no progrcs, "ith it. The stable
NND 927545

FEBRUARY 13, 1948

-

187

THE AEROPLANE

flight of K itchen's models. however. convinced Cedric Lee
that an aeroplane of such de~ign would be a succes,. 11nd late
in 1910 he acquired the patents. At the same time, G. Tilghman
Richards, who was a qualifii:d aeron:iutical engineer, became ,
~uffic1ently interested in the mailer to give up a budding
engineering bureau in order to join Cedric Lee and 10 devote
hib energy 10 tbe idea of a ·• safety " aeroplane.
__.._
Tilghman Richards began with systemat ic experiment, on
models and on large gJiders. Later, careful wind-tunnel test~
-:'x:
(including the o bservation of the pressure distribution) were
- -'made by him in a :!-ft. tunnel he had constructed at East London
College and al~o in tunnels-of tile National Physical Laboratory.
The preparation of the design was, therefore, uncommonly
~-ardul for this early period of 1911 - 1914.
In o rder to ap(>reciate the intention~ for the development, the
following quota11on from a paper read by Tilghman Richards
in about 1912 is illuminating: ... . . 1 he ve ry fnct of high lift occurring at small angles
rreans the provision of large area for l•nding speed resulting
in an inefficient altitude of the plane at high speed: and the
inherent instability of curved aerofoils means a continual
dependence on extraneou, controls carried at some distance
f_rom the wing by heavy and redundant Structure. . . . High
Fig. 6.-Huth annular biplane of 1909.
lift at small angles il> u~eles~. likewise h igh lift/ drag ratio at
,mall an,les, and what is required is the reversal of the normal
type of hft c urve i:iving little lift •lit small angles with low value and Gordon Bell. Finally it came to i;ricf when flown by
of the lift/ drag ratio for landini. . . ."
Lee himself without previous training. After a good
Seen from our pre.sent state of knowledge and development, Cedric
fliaht he managed to put it into a river.
a nd facing the burning problems of personal aircraft for the
Another incident happened with a subsequent annular
man in the street. it wo uld seem that this opinion is a very
i;o~ argument for further experimentation along the lines monoplane: the elevator jammed anct broke in flight. The
aeroplane merely pancaked to the ground, again preserving
indicated.
_The. experience with _powered aeroplanes was at first beset the health of i~ pilot, E. C. Gordon England.
These types in their final form had lateral control effected
with disappointment~. Famine P_oint, Heysham, was apparently
no t a spot from which aeronauucal experimenters could derive by differential deflection of the elevators. It was realized that
this elevon control was not very effective for lateral manceuvres.
any comfort.
The original Kitchen biplane with a 50 b.h.p. rotary engine yet the lateral stability of the wing proved so great that the
was wrecked by a gale, during I 9 I I. before flight tests could provision of ailerons seemed superfluo us. The loneitudinal
b~ m~de. After recort~truction some flight~ were performed stability was always satisfactory, once the centre of gravity was
wtth 11 at Sho!eham <!~ring 1911- 12: yet it never gave any properly located. Because of the great inherent · fore-and-aft
pr~~f of superior q~ah11es. The biplane had ailerons o f the stability, a separate elevator was, at o ne time, located on top
or1gmal Farman variety between the wings. Very soon the of the vertical fin and permitted the fitting of special ailerons.
biplane arrangement w!1s given up in favour of the monoplane. For directional control a vertical rudder was attached to the
A subs~quent experimental monoplane was nicknamed the stern of the fuselage at the trailing edge of the wing. A form
" Sccret-C1rct1: Plane ". ~r "Doughnut,'' the experiments being of tricycle undercarriage was employed.
shrouded agamst pubhclly (much against the interests of the - In respect of perfo rmance, the wind-tunnel tests indicated
dev~lopmen!), This annular-wing aeroplane (Fig. 7) was that a better lift/ drag' ratio could be expected than with a
equipped with an 80 b.h.p. rotary and test-flown by Gordon comparable conventionaf aeroplane., However, no co nclusive
England on November 23, 1912. at Shoreham. The flight evidence for this has, as,yet, been presented.
The third British monoplane of this type also had an 80 b.h.p.
was _remarkable and luck>; for the pilot, but. unlucky for the
precious craft. After havmg flown a large circuit on the first rotary engine. but this time it was located aft and. further, drove
attempt. the pilot noticed, when coming in to land that the the airscrew by means of an extension shaft. Unlike its pre­
d~cssors, ~~ dihedral was provided. and because of this the
aeroplane was exceedingly tail-heavy and getting out ~f control
the elevator. bei!Jg insufficient. At about 150 ft. above th~ flying qualities were found to have been greatly improved.
ground the inevttable stall took place: but the pilot managed From early in 1914 until the outbreak of the 1914-18 War
~~mehow to drop his mount upside down on to telegraph this unco nventional aeroplane was frequently flown (mostly
by Gordon Bell): it was demonstrated before Winston
wire~ and escaped without personal injury.
Wtth the reconstructed and improved monoplane many Churchill in the hope of securing orders from the Admiralty.
Altogether, 11,000 miles were flown in about 128 hours, a nd
s\iccessful flights were made by G o rdon England, N. S. Percival
eve~ people not previously trained as pilots were able to
fly 11. In Ma y, 1914. two such aeroplanes were being designed
for parlicipation in the Gordon-Bennett Race of 1915. When
the 1914-19 18 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.
In l?l~-10 Tilghman Richards succeeded in persuading the
Air Mm1stry 10 place a n order for a further experiRlental
aeroplane. But a week after communica1ing 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
fr~m the failure to have this develop'ment continued. As
Tilghman Richards stated many years ago:.. There i~ no!hing myMerious about th~ annular plane.
It affords high ltft at large angles, ha~ no >urble point and
has ~ good lift/ drag . rati_o for wings with a body. ' The
!Tiachm~ was very fast in p,ght. for its day, and extremely slow
m lan~mg: and there bei!)g three dislinct regions of lift, one
a ptero1d and two pterygo1d on each half-wing. the movement
of the centre of pressure was a resultant of three distinct
regional movements; ,tnd with slight modifications could be
made 10 move in any desired manner witho ut affecting the
general efficiency of 1he plane."
As _mentio ned. th«: c!rcular shape for the wing is not in itself
~ dec1s1ve cha".\c1enst1c. ?reviously. in 1908, A. H. Edwards
invented the ring-type wing with rhomboidal or triangular
An
shape_ (Brit. Pat. Spec. No. 4519 of February, 1908).
experimental aeroplane of this type, "The Rhomboidal,'' was
constructed and tested at Brooklands. It wa~ not s uccessful.
Fig 7.-Cedric Lee Monoplane No. 1 of TIighman Richards, 1912.
(To ~ conlit1u~d.)
NND 927545

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279

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THE AEROPLANE

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.)
HE SECR ET-CIRCLE "CONSPIRACY;• mentioned pre­
viously in connection with circu)ar-aerofoil aeroplanes. did
not lack congenially inventive spirits. Early in 1913 an engineer
in D ijon. M. Bou rgoin. made experiments with an annular­
wing aeroplane. The tests were unsatisfactory. 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
and Th. R. Young (Fig. 8).
In 1937 they secured a p atent
( Brit. Pat. Spec. No. 508,022 of December, 1937) for a non­
stallable monoplane of rhomboidal shape (i.e., leading wing
swept back and trailing wing swept forwards with the wing lips
merged together). This was provided with a conventional tai l
at 1he stern of a long fuselage and a number o f advantage~

T

qualified aeronautical engineer (Fig. 10). The 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 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 ud inal 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
tha t the vortex distribu1ion induced 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.
All this was said to be proved by extensive wind-tunnel
experimentation here and abroad. Designs of passenger trans­
po n aircraft reaching weights o f 40,000 lb. were prepared on the
basis of model tests made at the National Physical Laboratory
a nd elsewhere. T he results must have been so encouraging
that a n experimental monoplane with two 125 b.h.p. Menasco
e ngines and weighing 2,540 lb. was constructed late in 1938
(Fig. 11). This aeroplane flew indeed and was even publicl~
demonstraled (including one-engine flight) a1 a Garden Party
in May, 1939. Shortly afterwards the experimenter was killed
in an uneitplained c rash during a flight 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 a nd it is not improbable that this and
poor control efficiency may have contributed to the accident.
There was a lso 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).
11

Fis. 8.-Project by W arren and Young for a liJht twln­

en1lned two-seater of 90 h.p. (1937). The elevator is
fitted between fin and fuselage. There Is no tailplane.
were claimed. lo 1943 a model for a two-seater fighter with
tail turret show~ the separate tail omitt~d; special emphasis
was laid oo the triangu lar shape o f each wing and the effect of
sweep was relied upon. N othing more bas become_ known
since however b ut it is worth noting that the proJect had
been'based oa ;ound aerodynamic considerations.
lo 1933 the annula r wing of the German sculptor Antes
created a mild s~nsation bc<:ause ?f the good performance oC
models made to th is coocepuon (Fig. 9).
Some.what pecul iar was the aerodynamic ~onceP.tion of the
rhomboidal annular aerop lane of P. Nesbitt W11loughby, a

=

Fis, 9.--Model of the "annular wing " ~f Ant es. 1933.

Fig. 10.-frinciple or the W illoughby Delta design.

Another suggestion for an annular wing was made by L.
This. however. was concerned less with the
Peel, in 1944.
aerodynamic p roperties of such wing systems than with the
arrangement of two engines facing each other with their air­
screws. in order to overcome the torque reacuon.
A phenomenon of which aerodynamic experimenters were
alwa)ls well aware. but which aircraft designers failed 10
u1ilizc, was that wind-tunnel tests clearly proved good-natured
stalling p_roperties of wings having very small aspect ratios.
Yet even m the very e_arly days when centres of gravity were far
too far back on the old box-kites, the square shape of tailplanes.
then unaccountably in vogue, ma y have saved the pilot's bacon
more than once by its refusal to stall under eittreme provocation.
Later on science came and proved that a tailplane of "good"
aspect ratio was more eflkient. 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 o n normal aerofoils tests were restricted to rather
small incidences onl y. generally ucluding the range o f stall.

NND 927545

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THE AEROPLANE

c

>

\

I

\

I

I I

I

I

I I

\,'

I

I

\,'

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
10 give a very gradual, innocent stall, an~ that at v!!rY high
incidences. Yet, a part from a few broad-minded experimenters,
no designer drew the conclusion that wmgs of such shapes
promised safety in flight, t~oug_h it w~s known f~om ..~rly
practical experience that fly1Dg 10 the second regime, 1.e.,
at the stall, was positively dangerous.
It is true that spinn ing- Pa rker's "Spiral D ive "-was
attributed. in those days, to high i~cideoces, and that most _of
the lightly loaded rectangular wmgs used at that period
Howeve_r, :iccidental
rendered the stall relatively. in nocuo us.
~tailing was then, as now. the cause of the maJonty of all
crashes. And the nose dive following inadvertent stalls was well
.
known to be o f the most serious consequences.
Eiffel, Riabouchinsky, D ines, . Prandtl, etc., began the_1r
laboratory experiments on aerofoils of very small aspect rauo
and the results were generously published (how closely secret
they would be kept to-day!). Eiffe l showed that the ratio of
the resultant forces reached maxima for small aspect ratios _an~
that slender wings gave the greatest drag at ~ degrees 10c1. <lence, whilst disc wings had then t_he leas) res\stanc_e of _all.
Riabouchinsky proved that the maximum 11ft with d15:C Wl1'!8S
wa~ reached at incidences of the order of 40 degrees. whilst with
normal aspect ratios (exceed ing a value of 4) the maximum lift
Beyond
took place at incidences of 12 to 14 degrees only.
their critical incidence disc wings gave a gradual decrease of
the lift force whereas wings o f normal aspect ratio gave a
very abrupt ; nd unsteady one. 1 he tests by Dines on flat
plates in natural wind confirmed this info_rmauon and that the
observation applied 10 cambered aerofoils as well was also
proved (by Riabouchiosky). 0. Foeppl s_howed frof!l system­
atic wind-tunnel tests that a square aerofoil behaves, ID respect
of its lift curve in a remarkably d ifferent manner from one
having an aspec't ratio of 1.5, although wall interference and
Reynolds Number may have somewhat affected the results of
the tests.
.
Later, Pra ndtl was eager to point o~t that his aer~fo1l theory
did not hold for very small aspect ratios, and that, ID fact, the
induced drag of disc wings was less than the theory suggested.
In sP.ite of this, however, nobody seems to have he~ded the
possibilities implied and the " ~attle of the Aspect Ratios" was
decided in favour of slende r wings.
.
To be fair, it must be pointed out that there was one senou~
I

Fig. 12.-Experimental Hayden glider, 1925. Span, 19.7 rt. :
length, 13·85 rt.; wing area, 173 sq. rt. All-up_ weight,
310 lb. No lateral control.

MARCH S, 1948

argument against disc wings. The best aerofoil sections in use
prio r 10 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 o r stabiluy is. with such aerofoil sections, greater with
large-chord wings. On this consideration of fore-and-aft
stability and control, designers bad some justification for thcir
Yet quite
decision against experimenting with disc wings.
useful aerofoil secuons had a lready been used in flight which
had practically no travel of the centre of pressure and hence
d id not suffer from thi~ 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 d isc-wing
aeroplanes.
F. Handley Page converted an aerofoil, leaving an aspect
ratio of 6.25, into six square-aerofoil po rtions by five slots.
each parallel to the chord of the wing. By so doing he hoped
to have the low drag of a oormal wing combined with the high
Although a very
stalling angle of the d isc-type wmg.
slight improvement was claim~d , the principle was that of
eating the cake and having it too: the induced drag is respon­
sible for the stalling properties of the d isc wing and you cannot
have the benefits of the high drag without suffering its disad­
vantages. Moreover, in o rder to have the effect of the disc
Marginal
wing, the provision of mere slots is insufficient.
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.
There were other. although not quue as well thought out,
antecedents of the disc-wing aeroplane.
In the tint soaring­
flight competitio n on the Rhocn ( 1920), Friedrich Richter, a
burly naval pilot o f 20 stone or so, performed on a triplane
glider with wings having an individual aspect ratio of far kss
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 192S he constructed a glider with a win, having an aspect
ratio of only 2.25. The wing was nearly tnangular 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

c

==---=--

Fig. 13.-A French project of G. Abrial, 1929.
stern of a f11selage. Flyinf experiments in Styria were said 10
have proved satisfactory flying qualities.
Some early tailless aero planes, such as certain experimental
types of Rene Arnoux, had rather stub wings a nd heavily
reflexed (i.e., positively stable) aerofoil sections. A 19?9 design
of G . Ab rial showed an aspect ratio of 2.88, with, however,
substantial tip discs (which have the effect of increasing the
aerodynamic aspect ratio) a nd 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
a nd IS). Their resemblance in shape to the latest designs of
super-sonic aeroplanes is remarkable.
.
A Modttn Pioneer
Further intcre~t in the aerodynamics o f disc wings was
displayed by research workers with th.e arrival of Juan de la
Cicrv:i's Autogiro. This was indeed s<>mcthing like a circular
wing, a nd performance estimates were based on the properties
of such wings. Yet the question of stalling stability did not
a rise, bccau~e of the rotor properties.
The real pioneer of the disc wing was a very able American
research engineer of the National Advisory Committee for
Aeronautics (N.A.C.A.), who proved capable of following
independent lines of development. In about 1930 Charles
H. Zimmermann subjected the properties of disc wings to

NND 927545

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281

...

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/

Fig. _14.-A Russian • puabola' glider of 1924.

extensive wind-tunnel investigation and the publbhed reports
\till form the ba,is of prc~ent development. In places.
the re,ults confirm, qual1tat1vel)', the experiments made '.!O year~
before. But, as mentioned earlier, these experiments had been
praet1C111ly forgotten.
Zimmermann' s target has been the development of a really
fool-proof aeroplane for amateur pilots. It is no u<,c hiding
the fact that in n.:arly all accidents in which blame is attributed
to an .. error of /'udgment" on the part of the p1lo1, th.:
aeroplane is :ietual y at fault. The moq common causes arc
the consequences of inadvertent ~tailing.
Once this 1~
completely remedied, the overwhelming majority of accident
will become mere incidents or just fun, and instead of coroners
and hospitals. aircr.1ft manufacturer) and repair shop) will
have the benefit
On such very sound lines (which seem to be generally
acknowled$ed , but still far too often ignored), Zimrrcrmann
directed his main attention to the stall ing problem.
He
;>roved that small variations in the aspect ratio made profound
differences and that the shape of the wing tips also had a great
influence.

At the same time he confirmed that the induced drag of
circular or square wings is by no means as proh1b111ve as the
simple theory of the " horseshoe " vo rtex line would indicate.
He also proved that it was simply the induced drag due to the
predominant influence of the marginal vortices which brou~ht
about the behaviour at high incidence~: the idea that the
provision of oblique slots might help in this connection proved,
h owever, abortive.
An advantaae which Z1mmermann' s research brought to
liaht was that disc wings gave less profile drag at small
incidences (high-speed flight). because of the reducti on of the
relative thickness of the aerofoil sections. 1 h is drag reduction
has indeed become one of the rr.ain reasons for di.c wings
being adopted for aeroplanes capable of flying at ~reeds at
which the compressibility of the air needs to be considered .
Fo r supersonic flight disc wings seem, at P.rcscnt, to be a
necessity. Alternatively, for a given aerofoil thickness ratio,
!he height avail_able f<?r st,:ucture _and stora1te (J?Ower plant_sl
1s greatest within a disc wmg; this ma.,es for light and sutr

,
Fie, 15.-A ' puabola ' aircraft by B. I. Tschennowsky.

THE AEROPLANf

wing , tructures as well as for the pos\lbility of housing every·
thing w11hm a wing.
Hence 1hc1e a re very real design reasons for the preference
of disc wings, quite a pan from the ea~cd accommoda11on of
short-span aeroplanes.
Some R ernurkable Results
Zimmermann establ.shed that the optimum a~pcct rauo "'"~
found bet,..een the values o f 0.75 and 1.5. l he,c value,
include both ,quare and ctrcubr wmg ,hapes. For a g1Hn
win g sccu on (Clark Y) the latter gave the h1gh~t hft coefficient.
1.85 at 45 degrees incidence, compared "uh a value of t.:!4
at 14 degree, mc1dencc for an aspect ratio o f six.
Funhcrmore. an important result "'•'\ evidence that at ~,n
a,pect ra110 of unity hquare or elhpllcal .... ,ng,), and :11 an
a,pect rauo of 0.9 (" mg "11h faired ups), no tendcnc)' 111
autorotauon could be found. A circular " mg (:1,ix-ct raw,
of 1.27) ind c.llcd the po\\1hili1y of ~1urnrntation (1.e., ,rinningl
at incidence\ below that of maximum lif1. 1 he 1nm1biht)' of
,pinning before the actual ,tall is reached is. indeed, e,tra·
ordinary. All these rcwh, r.:fer to te,t• "ith the ( lar~ ,
aerofoil section.
Less establi,hed "as the contenuon th:11 d1..c wing would
11ive improved la11:ral and longuudmal ,1.1h1htv at low incidence,
1 hi, ..ecm, ,11II 10 be a moot point of the Flyin!l Saucer.
In Fig. 16, Fig. 17. and Fig. 18 some charactcri,tic result, ,,f

7

I!

II
I I

:;.,
't

...~

0-,

~.

••

CIA°', IIC,,O,.
-1....____..._

.,,.

JO'

-:

Fl&, 16. -N .A.C.A. tests by C. H. Zimmermann which prove
the extraordinuy sull1ng qual1t1es of disc wines,
Zimmem1ann·~ _wind-tunnel experiments of 1932 are given. It
1~ seen from F,,. 18 that the difference between the mc1deoce
of ma,umum hft and the gliding angle at m:i1t1mum hft
("ma'< •a ma'<) rem:im'I fairly independent o f aspect ratt,,, and
of the o rder of 9 to 13 degree,. 1 h1~ would me:in th.11
the attitude of the . disc-type aeroplane, when flattening out,
would not greatly d iffer from that of convcnuonal aeroplane,
In particular, there "'ould be no need 10 provide h1g_h under·
cama;ies for disc aeroplane, a .. their gliding path 1s steer
Thi, 1s an important difference from "''"IJS w11h lead1ng-cd~~
,lots.
. In P!'3Ctice, however: the landing of disc-wing aeroplane,
~•vcs rise to undercarriage problem,. As the induced dra~
mcrcascs rapidly "ith the reduction of !tying ~recd, when the
aeropla ne flattens o ut prior to touchina·do" n, the ihdtnti angle
.iecpens abruptly. This 1s particularly true of ta1llc..s de"gn,.
and the result •~. a strong tendency to pancake 10 the ground
a, so~n as the p1lo_t fl:\ltcn, out. Thu~ to avoid the nccc\,il)
of litt1!)2 _undercamal\cs able to sta nd the strain of abnormally
high sink mg ~pecds, 1t has been found practical to land "Jtll
powe r on.
For a ta11le~s aeroplane " ith an aspect ratio of three,
M. B. Morgan found that. without flaps, the trimmed l\liding
angle at 160 m.p.h . was th ree degree,: it increased to 17 degree,
at 126 m.p.h .. while the \tailing speed was I IS m.p.h. Thi,
pronounced , teepcn ing of the g)idintt anttle makes a mer~er
hct""ce~. the aeroplane and the helicopter an attrac11ve
propos111on .
. Another occulia_rity o f . !he di~ wing cstahlished b~
Zimmermann wns us scns111v11y to the , hape of the wing•ur,,

NND 927545

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282

THE AEROPLANE

•

MARCH 5, 1948

and _pseudo-circular and pseudo-square wings thus exhibit
c:,_
~ignificam d.fferences... 1 his also applies to the ground eff.:ct,
1.e., tbe tand.ng <juahues. 1 he prov1s.on 01 ob11que nozzle­
shaped slots at the lips yielded no useful r.:sults. In any case,
squo1re-cut tips Vvere found to be a disadvantage, w11h respect
10
to drag, as well as to other qualities.
Later N.A.C.A. research by F. E. Weick and Robert Saundefs
referred to aspect ratios of the order of 3 1n conncct,on w11h
slotted auxiliary Vevions flaps for the trim of tailless aeroplanes.
This constituted the first investigation o f what has b.x:ome
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
g
region.
•
:
Pancakes Ii la Zimmermann
10
0
The results of Zimmermann's research were so ~onvincing
Cl ARK I AEAO FOtl SECTION
""'0<
that a number of otherwise quite respectable designers were
(i-v-CA ZIMME~MANN,
tempted into experimentation with disc-wing aeroplanes. In
~l P No ()1)
:;
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. 1 his was seen in his
o ' - - - - ~ - - - L - - - J L _ ._ _..L._ _...L._......:~,
F-1020 monoplane which otherwise had a long fuselage with
a conventional tail. It was said to have proved very stable
.,
ASPEC T AATIO
in flight. but was noc further heard of.
An experimental
parasol monoplane with a completely circular win$, a camber
18. -Furthcr results from Zimmermann's tesu shown here
flap in the trailing edge and severely skewed ailerons Wl?.$
also indicate the advantages to be gained from disc wings.
tested in the U.S.A. (in 1934), with indifferent results. It was
shown in flight in news reels.
At about the same time Raoul J. Hoffmann. of St. Peters·
seem to. contradict the experience referred to above and it
burgh, Florida, an eminent aeronautical engineer of Austrian
w~s aunbuted. to. a ground effect arising from the rak~ of the
origin (known as the first to prove-in 1913-that the r:itio
wing-tips. It 1s indeed rea:.onable to e)(pcct that the presence
C '/C 9 governs optimum climb and glide with minimum of t_he ground would affect the formation of the marginal
L
D
vort1c~s to an ex\ent which may markedly influence the
sinking speed, took up development of the disc-wing aeroplane.
beh~v1our of disc wings during take-off and landing. Hoffmann
H offmann's Flying Saucer was a tailless aircraft with an
proJected a ousher and a twin-engined version but these types
aspect ratio of slightly over 2. The fi rst type was an ultra·
did not materialize.
•
li$ht single-seater with 36 b.h.p. Later a side-by-side two-seater
A further development was the Arup monoplane of
with an 85 b.h.p. Cirrus engine was constructed and flew well;
the wing tips served as ailerons and the elevators formed part
R: J. Hoffmann and C._L: Snyder at South Bend, Indiana. The
of the trailing edre. The aerofoil sectir,ns employed were
w!ng _shape ~as v~ry s1m1lar. I~ resembled a semi-circle flying
N.A.C.A. M.6 basically. with N.A.C.A. M.1 at the tips. Both
w11h 11s straight side a_s the_leading edge; to this wing, ailerons
are sections designed by. M. M. Munk. The former is a reflexed­
were added as special ups. 1 he aspect ratio practically
camber section with a practically stationarY, centre of pressure; corres~onded to. that of the previous Hoffmann types. Again,
aerofoils wtth little centre-of-pressure travel were used.
the latter is symmetrical
The central structure of the wing, the fuselage and the fin
1 he latest type ~ad it~ _tailplane and elevator separately
This
was of welded-steel tube; the wing had three spars.
locate~ over the wing tr:11lmg edge (similar to the .. Elytro·
little two-seater }"as stated to fly well and to exhibit ve_ry go(!d
plane o f De Rouge!). It seems that the longitudinal control
stability.
It seems, however. that the controllab1hty, m
at certain incidences was not satisfactory. 1 he ailerons which
particular directionally, was not satisf~ctory. 1 he visi(?n fr(?m
formed part of the wing shape and reduced the aspecl ratio
the cockpit must have been very restncted--a moot point wllh • to a value ~f I:15 had a triangular shape and were greatly
all these designs. A speed range from 28 m.p.h. to 13S m.p.h.
s_kewed (taking_ into account the obliqui: flow over the wing
was claimed. The empty weight was given as 900 lb •• and the
tips). The engine was a 70 b.h.p. Le Blond radial; a tricycle
wing loading was 5.5 lb. / sq. ft.
undercarriage was fitted.
One remarkable characteristic observed during the flying
With the oilot alone, a gliding speed of 23.S m.p.h. was
tests of Hotrmann's aircraft was that, when comin(! in to land.
r~o_rded (lhe wing loading was about 3.3 lb./sq. ft.) and a
the approach was steep: yet prior to the fl lltening out and
gliding angle of 21 degrees was mea~ured, with a sinking speed
just before touching down, the glide flattened. 1 his would
of 12.3 ft. ocr si:cond. wh.ch ~an be accommopated by a sturdy
undercarriage witho ut nattening out of the glide. 1 he maxi·
mum speed was 86 m.p.h .. and the take-off was stated to require
C
l MAJ(
C
S secs. in zero wind.
l MA.(
0 MIN
r
0 MIN
Several more Arup types seem to have been constructed
,001----.U---4---1-- -4-- --4-- - - - + - - -~
an_d _flown during 1935. 1 h~ flying qualities were pr.iised­
ghding angle~ or I : 2.6 bemg quoted- and the published
performance figures sounded extremely good. Yet, for reasons
never disclosed, the production stage was not reached and the
CI..Akl( T AUl,OfOtL SfCTl()N
development ceased abruplly. It is worth noting that Charles
C,.ACA • IP No u,)
Zimmermann himself has taken no part in this development,
b1;11 he was an interested spectator at demonstration flights
..,z
.,,.
wnh an Arup monoplane at Langley Field.
~ ~ 60
::,., l5
An Italian "Tortelllno "
"•r
"<It
At the time .of the Arup development (1934). F. Piana
fl"
"'
Canova. an Italian, began to embark on a development for a
z
~ •>
tajlless aeroplane with a low aspect ratio. In May, 1935, he
It
~
"It• 0
ti
secured patents for a rhomboidal wing, one diagonal of which
11f 2
10
z
coincided with the direction of flight. 1 he ailerons were to
c!, "
6
~
be located at the lateral apices. elevator and rudder at the
i;
rear apex. while the airscrew was in front of the leading apex.
Another patent related to bi-convex aerofoils with ducts and
AA
o·
control valve~ for the pilot, enabling the latter to neutralize
ASP(C f U flO ( •' 1J
the negative oressure on the forward ventral surface when at
negative incidences. The latter patent was, apparently, never
submitted to flight experiments.
Fig. 117.-These resulu from Zlmmermann's wind-tunnel
tests on disc; wings (1932) clearly show the character!stits
(To ~ confin~d.)
of low aspect ratio aerofoils.
NND 927545

i

--..

.,

jc

;•f

J

" ...

!i

J

t

•

,

MARCH 19, 1948

337

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
l· L I F-••n S w.:rc made in I unn and at Rnme
WofI of0five-·11h1,UNC:anovo1
project\ {de-.cnbcd m the prcvtom tn\1,11ar1de). It " in1erc,11ng 10 note that 1he Canov.1

"'!Cnl

d1-.c-wmg lype, d id not mal.e u,e of rellc'<ed~ambcr aerofoil,.
S1abili1y ,ind mm could . 1hercforc. be -..:cured only by an
upward, dcllec1iu11 of enlarged eleva1or,.
F.arly in 1935. :in ·open ghdl!r of 1he " Zoegling" t} pc wo1~
con,1ructed by a ,~ ilan firm and M. A. Garbell made fairly
~ucce,,ful l11ghh w11h 11. He reported that the longitudinal
stability (w11h the enlarged eleva1or) wa~ good and 1hat
par.i.chute-lil.e landing, could be performed.
rhc lateral
stability ch.i.racteri\lic. however, proved deficient. ~ince a
•• Dutch-roll " motion was experienced: turn, were of quc,tion·
able steadine,,. In this rc,pcct, in~uffidcnt damping 1n foll
and yaw a_re mentionr.d. Wi1h winch-launching, thi~ glider
reached altitude~ of 600 fl.
On 1he ba"' of thi, dc,ign, a ligh1 aeroplane wa\ developed
and the Italian Government financed the conMruction of two
l~~gcr e,-perimental aeroplane~. includmg one with 130 b.h.p.
Gip,y engine. A faial accident de~ribcd as "not necessarily
retlccti~f? on 1he 1echnical _merit5 of the design," cau,cd the
authorities to change 1hc1r minds and 10 terminate this
development.
1
A Return to Child ish Things
Aeroplane, with a long, deep tail affi'<Cd to a smalhpan
wing form a development of lhe low•tl'pect wing in another
direclion. Although the overall a~pect ratio is low wi1h such
a n arr.rngemcnt. the wing system i, not tha1 of a di-.c. It is
more akin to primitive kites or. belier, to the paper dart of
our school day~ which. a, we may be able to remember wi1h
some mental effort, exhibited quite remarkable nying quali1ie,
and made better use <>four schoolbooh than we ever expt-ctcd.
A rcpresent:11ive of 1his aboriginal 1ype is shown in Fig. 19.
It crashed during the first tests (which would not seem very
surprising in view of the; arrangement of engine, and air;crew,).
Ano1her Je,s eccentric arrangement was the French Payen
single-seat racer of 1935. This was a daring experimental
type with a 400 b.h.p. radia l engine. A n improved type, this
time more reasonable--a 70 b.h.p. light aeroplane- was
constructed in 1936. To a very small. conventionally tapered
wing, a large triangu lar tail was fitted: the wing alone had
d ihed ral. and the overall aspect ra1io was about 1.76. No
flights have bc.:n reported of one of these Payen aeroplanes.
but take-off attempts with the ~econd type seem to have
sugges1cd that with 1he small span the 1orque reaction of the
air,;crcw ca nnot be adequa1ely dealt with.

Fig. 19.-An American "Flying Flapjack" w ith two engines.
It crashed while under test (1938).

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 100 b.h.p. engines mounted in 1andem
m the long fuselage. 1 he pilot's cockpit was located at the
root of lhe fin, and a single·lrack undercarriage w.is adopted.
1 here were. however, far too m.iny untried feature in th"
unusual design 10 make ii a ~rious proposi1ion. Nothing
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.
Hoth 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 T e~la (famous for his elccirical
experiment~ wi1h high-frequency phenomena) bccured a pa1en1
for a taille,~ aeroplane equipped with a large lifting air~rcw
pcrmi11ing a vertical ascent.
In 192 1 Claud Dornier ~ecured a pa1ent for a eonvcnlmnal

f

lL:

L

120

.__ ._

GI

'--- 100

-

~ eo t--t--;illt":!'-~ -+7"lr--+--+..-t---c¥~--+~

1

...

...a:; ~60
...~
w

0
._u
,o

t

:::;

w

~

oQ-"11~t---t--t--:,~o- r-+ ---l- +-~ 20- +--+--I
I

ORAG C0EfFICIENT

100)

-

I- 0

'--

0

~j

19"
0

ASPECT RATIO

.»

+

1 SQUARE v, ING
2

~(

A

3

h

0

5

4l

6

()

7

~

"

...

n

80

•

c• t

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,_

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-

1/lO C

1110 C

0

• '

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1·
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i€

ID

I

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10
I
DRAG COEFFICIENT

I

20
0. :

NND 927545

I

20

I

< 100)

Fig. 20.-Llft and
drag of wings of
different aspect
ratio. (Left) W indtunnel results
obtained
at
Goettingen , in
1920; Goettingen
389 aerofoil with
10 per cent. t hickness and square
wing tips. (Right)
A reduction of the
r esults to an
aspect ratio of
f i v e.
by t he
Prandtl Aerofoil
Theory of t h e
Ind uced d ra g ,
s h o w s t hat a
s quar e aerofoil
(aspect ratio of
one) does not
follow the theory.
Its induced drag is
less than pre­
dicted by t he
"h orse-s h o e
vortex " assumpt ion.

\

THE AEROPLANE
•
100 C
t
~
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t:
AR 1
1IO
I
,v
AR~
00
'°
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t 1,10
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1,,1" fif (r
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cf
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10
°
10
or INCll)[NC( ( O!GRCES i
o·
...
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O+
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00
t:
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-
~- 100
V
v v l,o' /
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L-/
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LA>-
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L,CI"
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:a-:
--;?
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80
MARCH 19, 1948
. 338
t
ro
'°I
I+
t
ASPIC.T RATIO
a
1
+
?
.0.
J
Aou,hf
WING
,__,__
• •
b
.. ,· -
.o
I
,__
~
()
--<
10 •
10
I
AN(;l[ Of tNCIO(N(( t OIGRH\ I
0 '
IO
~
aeroplane with take·off as helicopter {Brit. Pat. Spec.
No.161,948). Earlier still (in 1916), the German, F. Bendemann,
a noted fesearcb worker on a1rscrews, conducted a secret
development o f an aeroplane with a large tilting airscrew
The
capable of rising and descending as a helicopter.
development of this air observation post was later discon•
tinued in view ot the Austrian helicopter experiments by
Th. v. Karman and Petroczy.
From his early experiments with lifting airscrews,
F. Bendemann found that hoverihg without forward movement
could be achieved- when the power loading of the aircraft was
less than a bout 9 11,.. / b.b-.p. With fighter aeroplanes, such
low power loadings were already then being approached1 and
operat ional experience bad indeed shown that certain single·
sealers could. under favourable conditions, be held in attitudes
a pproaching that of hov.ering (later the Fokker D.Vll biplane,
with a large airscrew, became renowned for this trick 10 air
combat on the Western Front). Attempts to revive the project
~ta la ter date failed. and with the suicide of its promoter (who
had gone into the Civil Service), all interest lo the development
ceased.
•
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
He secured basic patents and constructed during
wings.
1934·35, in the cellar of his home, a man-carrying aircraft of
bis design. This had a wing of only 7-ft. span, with two
airscrews driven by two 25 b.h.p. engines. Due to persistent
engine trouble, no flights were made; the Little aircraft showed,
however. all the C$SCOtial features of the present types.
In 1937 he granted a licence for his patents to the Chance•
Vo ught Aircraft Division of the Unik:d Aircraft Corporation
in Strntfort, Connecticut, and /'oined this firm for the further
development of his ideas.
t is possible that the public
conception of the mysterious "Flying Saucers" has origmated
from this develo,,ment.
Zimmermann's intention may have been the development o f
a safety-first aeroplaoe 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
flights and proved that the ideas underlying the design were
practical.
The principle is that, at h igh speed and when cruising, the
aircraft shall fty 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 rarher 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 fia),ter for use from aircraft carriers bas been the Chance·
Vouaht XF5U·l 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 lesa than unity. Strictly
speaking, however, it is not a genuine tailless aeroplane because
of the attachment of a trimmmg elevator to both sides ot the
wina. The reason for such excrescences is the need to locate
Fig. 21 . - LI ft
curves of aerofoils
of different aspect
ratios. (Left)
Wind -tunnel
results obtained,
in 1920, at Goet•
tlngcn, w ith
Goettlngen 389
aero fo i l and
square t ips. 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 t hat
wings of very
small aspect rat io
do not follow the
theory in respect
of the induced­
Incidence correc•
tlon.
control organs directly in the slipstream of tht: paddle-like
airscrew rotor... T he twin rudders, too. are in the slipslfeam.
Unlike the V-173 type, the XF-SU· l has an all-moving tail
surface and the undercarriage is retractable.
This interesting hybrid has 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.
A special oroblem was the design of a transmission ~ear
which a llows both rotors to be driven from either of the eogmes
- 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. The wing loading is
rather high. reaching the order of 40 lb./sq. ft.
The Real Flying Saucer ?
Since this experimental t ype was produced, further progress
has been made in the development. IL seems that axial-flow
gas turbines have been installed, and it is quite possible that
a combined oropulsion with thermal jet and airscrew rotor
is alt:eadv under test. Wilh this, for slow flight (take-off,
climb and landing) the rotors a re driven by the gas turbines,
while at high speed the rotors are declutched a nd feathered
and pure jet propulsion is used. This would, incidentally,
(
~01! 1---1---1------.1---1----1----1
;
0
~
,.
<
-
i
Q
...-
:::
iSV
..,
~
NACA 14 SEC11C)N:~
0-00,
._N• '1·1 , 10'
0
i ~
,.
~
~
0.~L T!HI
-
...
I
T{C
~01
0-ll
0-16
~IO
0 •1'
AU,0r0tL TMICKNESS A.ATIO
Fie. 22.-lncrease of profile drq with section thickness, at
:zero 11ft. The lfnporunce of the tip shape Is obvious.
The data refer to an aspect ratio of flve (From D.V.L. windtunnel tesu at low turbulence).
NND 927545

.,
0·3

...

<=o,

0

THE AEROPLANE

339

~ ARCH 19, 1948

r - - - - - - - -- - - - - - - - - - - - --i~

M. B. Morgan has recently communicated the following
values for the limit of stability at the stall from this araph:Upper llmic of th• Ansl• of Swetp,back (r•lerred
to th• l chord) beyond which Hll••tall can be
expected

A,poc, Ratio 11.•qulr•d

Ocareu
6S
S4
46
38
2S
14

s

1
2
3

'
••
6
8

It is thus advisable to combine sweep-back with low-aspect
ratio w!1en s~fc stallin_g is required.
. Consaderataon, of high speed lead to a ,imilar combination.
since both feature~ tend to delay the shock stall. We have.
as ~ res!lll, the rare ca~ i;,f two quite d ifferent aspects of an
o-a 04 1·0
enginee~ing_ problem pointing to an identical solution.
1 he incv11able result has been the development of arrow­
sh<;1ped:. more ?r less triangular, . disc wings, termed " Oelta­
Fig. 23.-lncrease of xero lift profile drag with thickness ratio
Wangs, _for lhgh~ at sp~eds which are trespassing into the
of symmetrical aerofoil sectldn. The saving In profile drag Is
tr~ns•s?nlC velocity rtg1me. Another advantage of such
one of the advantages of disc wings because of their thinner
wings as that when the shock stall occurs. the backward shift of
aero~oll section. (Data from Gerber, Zurich Report No. 6).
!he centre of pressure is less than with normal wings. The
induced drag doe, not count quant itatively at tbeg high speeds
Development of such abnormal aeroplane types began i~
explain the extr~ordinary ability of the reported •• Flying
9e:many during the War_. following the progress accomplished
Saucers·• to be able to fly very fast and high, and also to hover,
•~ 1et and r~ket propulsion since 1937, which had shown that
ascend _and de_sceod with practically no forward speed. No
flight . at sonic vcla<:IIY wa, a r,ractical proposition. A few
~ther a!rcraft 1s known to do tha t. On the other hand, it is
experimental delta-wing types had been brought to initial flying
ll!(ODCeavable that whole squadrons of such unconventional
te~t, when the War came to a close.
rare
is
It
exercises.
air
at
atreraft could already be observed
. The German ~evclopmcnt had two d istinct aims, resulting
for military developments to progress as quickly as all that.
11_1 two separate hn_es of approach. The immediate target neces­
zero
from
range
speed
a
. For operatao~ with gas turbines
by the Allied bombing raids. was the creation of very
satat~d
claimed
been
has
m.p.h.
.500
than
more
to
(1.c., hovcrin~ flight)
fighters or fighter-bombers which could surpass in speed
Jct
fast
plane.
helicopter-aero
n
t-Zimmcrman
for t~e Chance:V~ugh
Mc 262. _Secondly, there was the long-term develop­
the
even
amazing
an
such
that
doubt
to
reason
httlc
1s
there
Technically.
~ent of a supersonic aeroplane capable of flying over very lon11 \
spec<! range can be attained with the combination power plant d1sta~es.
such n, from Europe 10 America and back. and
menuoned.
the way. Jt i, perhaps not too
Jncidcntally, as there is not as yet a standard term for the dropp11_1g a born~ or two ~ndevelopment
had some connection
fa_ntastac to surm1,e that t~•s
combination of an aeroplane with an helicopter, the name
with the research on atomic bombs and bacteriological warfare
•• helicoplane •• is tentatively suggested.
instituted by the Hitler Gang.
The. oth~r line of engineering approach which has led to
For th~ immcdia!e. target, orders for interceptor-fiahters were
the da..c-winl! aeroplane of near-saucer appearance derives
notably with the Honen brothers
from the trend towards very high flying speeds within the sonic placed wath cnterpming firms,
(both pets of the Rcichsluftministerium) with
range of velocities. and in panicular at great altitudes. As now and Messerschm111
the Gotha Works, ttenschcl, Junkers, Heinke! and Arado (a
commonly realized, the compres,ibi 1ity of the gaseous medium
cntcrpra~). etc. In order to facilitate experiment~
sets a speed limit for conventional aeroplanes. This limit is G?vernmentunu~ual
aarcraJt ~ypcs and to enable an exchange of
~•th rather
reached when the speed of flight approaches sufficientl y to the
a special research aerodrome was built at
expenences,
ideas.and
This
air.
the
through
propa&3ted
is
veloc11v at which sound
with all facilities for flight testing
Berlin)
(near
(?ranien~urg
and
temperature.
air
the
on
solely
depends
"acoustic velocity"
ve_ry l~ng wide runway, and workshop, for
is, therefore. lower at altitude. Hence. compressibility effects (in ~anacular,mod1fica11on,
were provided). This was placed
repairs and
begin to be felt at lower speeds when flying at altitude.
under th~ command of a capa~I~ _technician, Lf.-Col. Kncmeyer.
When the "shock stall," due to the compre~sibility of the
On this aerodrome, all the in111al and development tests with
air, ,;cts in, the lift is catastrophical ly decreased (hence the
novel prototypes had to be made. When the Russians collected
justification for the expression "shock stall "), the dmg ri,cs to
the aerodrome, they were agreeably surpri,;ed to d iscover some
enormous values, and the longitudinal ~tability i, grossly
aircraft ever constructed. It has since
impaired by a rapid backwards shift of the aerodynamic centre of the most progressive
cenain that thcr have made intelligent use of this aero­
a~ well as by fluctuations in the flow pattern at the wing. The beco!11e
nau11cal treasure as wcl a, of the technicians collected then and
experience of phenomena of such distressing nature has given
Of the German firms interested in the develop·
afterwards.
is
One
rc,carch.
aeronautical
in
rise to two distinct aims
one. the well-known Junkers works at Ocssau has
least
at
ment,
Numbers;
Mach
higher
to
phenomena
the
of
to d elay the ono;et
t!"llnsferred ~o Russia, lock, stock and barrel.
complete!y
been
within
flight
permit
would
which
wings
find
to
i,
aim
the other
ts and ~e 1snen were urged to volunteer for
sc1cnt"_
the
of
Most
or
within
"
alternative.
The
regime.
tran,-sonic
the
or throuF,h
Rus~m. Fe~ could afford to refuse.
11_1
work
developm~nt
since
definition,
of
impediment
necessary
a
still
is
through,'
According to reh_able mrorma11on, amont: the interceptor
we do not know yet if Mable, steady flight will be at all
at the time of the Occupation.
possible within the tran,-sonic regime (extending from about prototypes at 9ran1cnburg,
were the following:-One Honen taille,, delta-wing, which had
0.8 to 1.2 Mach Number) while there is certainly that beyond
been dama_ged d(!rmg tests and ~as undergoing repair: another
this tran~-sonic regime. i.1:., within the supersonic regime, ~table.
Honen ta1lle,, Jct-fighter was J.ust ready for it~ first test,.
steady flifht can be predicted.
the latest version of the lippi-;ch-Junk er,,·
Two \ample mean, have become known which delay the There was also
dev~lopmem of . the Mc 16.\-C: another advanced Junker,
occurrence of lhe "shock stall" until much higher (but still
Gotha. and several re;,earch gliders.
sub,onic) flying speed, are attained.· One is sweep of the design: an experimental
Hitler's Last Secret Weapon
, leading edge of the wing, either a, sweep hack o r a, ,weep
forward. The othe~-a Farnborough _discovery of nearly
The G~rman long-term development of an aeroplane capable
30 years ago, when high top ,peed, of a1r<.erew, were investi­
~f reac_hing truly superso nic ,peed, discarded the gaHurbine
The
sections.
aerofoil
thin
gated- i, the adoption of very
1et engine. It wa, based on the ram-jct or aerodynamic pro­
latter lend,. as we ~ave pointed out already. straight to aerofoils
puhivc due~ (" Ath_odyd ")-the simplc~t en11ine ever' invented
,tiffness
structural
of
rea,on,
for
when,
ratio
of low a,pect
1 ~e. ram-Jet, a widely d1,cu,,ed invention by the genial Rtnci
'
a certain wing thickne,, is required.
Lorin in 1~1~. had been c~pcrimented with in Germany, notably
Toille,s
of
s
Characteristic
"Stalling
the
ln the discu,sion of
hy the Austrian Cugcn Saenger (for whom a special laboratory
Aeroplanes'' (THP AER0PLANr for April 2.5. 1947). it was
had been built hy the German authornie~ in 1938), by Otto
landing,
and
take-off
ng
duri_
i.e.,
soecd,.
,hown that a_t low
Pabo\t, of Focke-Wulf, _an~ by others. Following a suuestion
swept-back win1t,s ,uffer from the d1s.1dvanta11e of in,tability
m~de by Al~xander L1pp1sch (formerly known as an eminent
wing,
wept-back
&
sw«:ep-back,
pronou_n~ed
W11h
,tall.
the
at
sa1lplnne des1(tner and resc~rch worker on _tnillcs, aeroplanes).
of normal a~pcct rataos exh1b11 the vice of" ,clf-,talling," due to
prog~e~, had been made wath the combustion of solid fuel in
premature tap stall. It was al'° shown that this vice can be
ram-1ets. Such fuel took the form of ~olid blocks of ~pccinlly
remedied bv reducing the a,r>ect ratio. and a curve based on
r,rcpared coal which lined the walls of the doct. This develop­
exten,av~ wind-tunnel te,ts CT11c ~ER0P~~c for Jul y t I. 1947, ment ha~ bee~ perfected by the German Research In1titutc­
for Soarmg Fhaht.
p. 47, F111_. 8) proved that there 1, a d astmct relation between
(To ~ continued.)
a,r,ect ratio and an11le o f sweep-back in this connection.

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