Documents / Report
This August 1949 technical report from the US Air Force Air Materiel Command presents Project Grudge's investigation of unidentified flying objects through January 1949. Drawing on consultants including Dr. J. A. Hynek, Rand Corporation, the Air Weather Service and Dr. P. M. Fitts, it explains most of 244 incidents as balloons, aircraft, astronomical phenomena, hoaxes or psychological errors. It concludes the objects pose no direct threat to national security and recommends reducing the investigation in scope.
Group 9. The fifth group includes reports of objects in which eredence can be plied. ## General Reference. In general it is noted that few if any reports indicate that the observed objects make any noise or radio interference. For are there any indications of any material effects or physical cause attributable to the observed objects. ## SUPCHEART, P. JRT 1. This report will consider mainly the reports of groups 1 and 2. PART 2. CH K98JRLK KX/ALT CID OF NO REPORT. Section 4. That can be deduced concerning the nature of an unknown aerial object from a single sighting. There are two problems first, how much our deduced observing the nature of the objects from geometrical calculations alone; second, how much more can be deduced if, in addition, it is assumed that the objects obey the laws of nature as we know them. Concerning the first problem it can be stated that only ratios of lengths, are rates of change of such ratios can be accurately determined. Thus the range and size of such objects cannot be determined; and it is noticeable that reports of size of the observed objects are widely at variance. However, angles, such as the angle subtended by the object, can be observed. Likewise there is fair agreement among several observers that the diameter of the objects of Group 1 is about ten times their thickness. Although velocity cannot be determined, angular velocity can be, and in particular the flutter frequency could, in principle, be determined. All that can be concluded about the range and size of the objects, from geometrical considerations alone, is: 1) from the fact that estimated
Report, from the classic collection. The PDF is mirrored here; the original link is under it. The text was read from the page images by an OCR model; expect the odd misread word. 413 pages are in the text index: search them above, or from the library's search.