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~f\DENTlAL:- e-Incident No. Exhaust Trail Heading Altitude Ft. Speed lffect on Cloud• l t:one 320° 1000-sooo rt. ~00 mph lot at&ted la. lb 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 llorthweaterly Undetermined Terrifie lot stat.d 7 None Southweat 50000 fto Terrific - faster than any object ever seen by him lot stat.cl 8 8a 9 Rone- Jlone Not atated South South S01..-th 40000 tt . 40000 rt. High over Globe Mille Terrific ?errifio Terrific lot atated Not ,tated lot stated 10 !Jone Northwest llot stated Cruised for Not atated 46 min. at oonventional airline apeed (180 mph) then rapidly dis- appeared 11 Not stated OTer north end lot stated ot Lake 1'o.sh- ington llot stated .ttoi; ata.ted CG."f,DENTIALNND 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.