Documents / Case file
This is an initial Project Sign progress report dated April 1948, sent from Headquarters, Air Materiel Command at Wright-Patterson Air Force Base to the Chief of Staff, U.S. Air Force. It tabulates about 100 unidentified flying object reports received through February 1948, covering shape, size, number of objects, speed and exhaust trails. Dr. Irving Langmuir found the data insufficient for a positive identification. Headquarters judged that a low aspect ratio aircraft using boundary layer control could reproduce many of the reported characteristics.
From the source: Release of 2026-07-10 Incident: 1948, Various. 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.”
cot~FIDENTIAL Incident 10. color Shape Si•e sound 50 Stated aa queer 11.&ht. Referred to aa aauoer but not stated as being ot thie detinite shape. Kot stated 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 58 Blaok Saucer (not det1n1tel7 1tated •• being tbia shape) Larger than C~4 airplane Not stated 59 Incandescent 11Cht without appreciable blue and no redd1eh tinae. Hot stated Not atated Hot stated 60 Plame oolor Diec shaped (the 11'ter glow •de 1t look like a oone) Barrel Bead, dinner plate am the aise ot a plane tl71,ng hi&h. Wot stated 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• neaa. lot stated 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 67 Jllutal col01" top 1urtaoe al1ghtly IJ.-6 tt 1n le~h ll'ot stated 57 h1ghl7 po111h- ournd-larger 1n front 4 ed chi-Ollium. than 1n the rear . :~e:O-l 1nchea liOMflDENTIALNND 927545
Case file, from the pursue collection. The PDF is mirrored here; the original link is above. 45 pages are in the text index: search them above, or from the library's search.