The Twining memo is in the archive under a file name that gives nothing away. The file is UFOP-f8bfdc1e, titled 18_100754_ General 1946-7_Vol_2, agency listed as Department of War, catalogue date 12/30/47. Older links to the same file used the ID UFOP-10. The catalogue date belongs to the last letter in the story. The memo itself is in the folder twice: subject "AMC Opinion Concerning 'Flying Discs'," dated 23 September 1947, signed N. F. Twining, Lieutenant General, U.S.A., Commanding.
A reply to a question
The memo answers a request. It goes to the Commanding General, Army Air Forces, attention Brig. General George Schulgen, AC/AS-2, the air intelligence office at headquarters, and opens: "As requested by AC/AS-2 there is presented below the considered opinion of this Command concerning the so-called 'Flying Discs'."
The same paragraph says where the opinion came from. It rests on "interrogation report data furnished by AC/AS-2" plus preliminary studies by T-2 and the Aircraft Laboratory of Engineering Division T-3, and it "was arrived at in a conference between personnel from the Air Institute of Technology, Intelligence T-2, Office, Chief of Engineering Division, and the Aircraft, Power Plant and Propeller Laboratories of Engineering Division T-3." The sentences people quote were drafted by an engineering conference and signed by the commanding general.
The August question behind it
The same folder holds the earlier half of the exchange, and it changes how the memo reads. On 22 August 1947 the Collection Branch of AC/AS-2's Air Intelligence Requirements Division sent a routing sheet to the Deputy Chief of Air Staff for Research and Development. It said a study of sighting reports "selected for their veracity and reliability" showed a common pattern, and before going further it asked for assurance that no Army Air Forces research project had the characteristics on its list.
Among the traits: a metallic surface; a trail, when seen, of "a lightly colored blue-brown haze, similar to a rocket engine's exhaust"; circular or at least elliptical, flat on the bottom and slightly domed on top; about the size of a C-54 or Constellation; and "Flights have been reported containing from three to nine objects, flying good formation on each other, with speeds always above 300 knots." The last item says the discs "oscillate laterally while flying along, which could be snaking."
The reply, dated 29 August and sent from the Deputy Chief of Air Staff for Research and Development, is one sentence: the Army Air Forces had no research project with the characteristics described.
Put that list beside the one in Twining's memo a month later and most of it carries over. "Always above 300 knots" becomes "normally above 300 knots are estimated." The formations of three to nine stay. The shape stays. The wording got more careful on the way to Wright Field.
Paragraph 2, the part that gets quoted
Paragraph 2 is a list of opinions lettered a through h. The first three:
"The phenomenon reported is something real and not visionary or fictitious."
"There are objects probably approximating the shape of a disc, of such appreciable size as to appear to be as large as man-made aircraft."
"There is a possibility that some of the incidents may be caused by natural phenomena, such as meteors."
The third one tends to fall out of retellings. Sub-paragraph d gives the performance that worried the conference: "extreme rates of climb, maneuverability (particularly in roll), and action which must be considered evasive when sighted or contacted by friendly aircraft and radar," which "lend belief to the possibility that some of the objects are controlled either manually, automatically or remotely."
Then e, the composite description, in six numbered traits: "Metallic or light reflecting surface"; absence of trail "except in a few instances when the object apparently was operating under high performance conditions"; "Circular or elliptical in shape, flat on bottom and domed on top"; "Several reports of well kept formation flights varying from three to nine objects"; "Normally no associated sound, except in three instances a substantial rumbling roar was noted"; and level flight speeds normally above 300 knots.
The paragraphs that rarely travel with it
Sub-paragraph f is an engineering judgment. It is possible "within the present U.S. knowledge," provided extensive detailed development is undertaken, "to construct a piloted aircraft which has the general description of the object in subparagraph (e) above which would be capable of an approximate range of 7000 miles at subsonic speeds." Sub-paragraph g says any such development "would be extremely expensive, time consuming and at the considerable expense of current projects" and, if directed, should be set up independently of existing ones.
Then h, three things to keep in view. One: "The possibility that these objects are of domestic origin," the product of "some high security project not known to AC/AS-2 or this Command." Two: "The lack of physical evidence in the shape of crash recovered exhibits which would undeniably prove the existence of these objects." Three: "The possibility that some foreign nation has a form of propulsion possibly nuclear, which is outside of our domestic knowledge."
So the same memo calls the phenomenon real, says there is no recovered hardware, and leaves room for a secret American project. That last item sits oddly beside the 29 August reply, though "not known to AC/AS-2 or this Command" allows for a project neither office had been told about. Nothing in the folder says whether the conference had seen the 29 August reply.
What it asked for
Paragraph 3 recommends a headquarters directive assigning "a priority, security classification and Code Name for a detailed study," with complete data sets going to the Army, Navy, Atomic Energy Commission, JRDB, the Air Force Scientific Advisory Group, NACA, and the RAND and NEPA projects, a preliminary report "within 15 days of receipt of the data," and a detailed report every 30 days after. Paragraph 4 closes: "Awaiting a specific directive AMC will continue the investigation within its current resources in order to more closely define the nature of the phenomenon."
The next day: a drawing and the Horten file
On 24 September 1947 AMC sent another letter to AC/AS-2, signed by Colonel H. M. McCoy, deputy commanding general for intelligence at T-2. Following a telephone call from Major General George McDonald that day, it forwarded a drawing titled "Loedding Flying Disc," designated LD-2, with a request: "Because of patent rights involved, it is requested that a record be kept of all persons reviewing this drawing by witnessing with signatures and dates directly on the drawing."
The same letter inclosed a Royal Aircraft Establishment Technical Note, AERO 1703, on the Horten brothers' aircraft, with a list of page references considered significant in relating the Hortens' thinking to the alleged flying saucer case, among them photographs of the Horten "Parabola" and the Horten IX. It cites a 9 June 1947 report from the U.S. military attaché in Moscow that 1800 aircraft based directly or indirectly on the Horten VIII design were being built for bomber squadron use, the Russian version jet propelled. It also inclosed a T-2 report, "German Flying Wings Designed by Horten Brothers." Whatever else Wright Field thought, the paperwork it reached for was aeronautical.
Silence, then Sign
Then nothing, as far as the folder shows. A December cover letter from AMC's Chief of Intelligence to the Chief of Staff, attention Major General L. C. Craigie, confirms a conversation of 9 December 1947 and attaches copies of both September letters. It notes: "Comments of Headquarters, Air Force on these letters have never been received by this Command." Continued reports from qualified observers "still makes this matter one of concern to Headquarters, Air Materiel Command."
The answer is dated 30 December 1947. In the extracted text it is mostly noise, but some of it can be read: a directive that AMC set up a project to collect, collate, evaluate, and distribute information on sightings and phenomena in the atmosphere that could bear on national security, assigned priority 2A, with reports on a quarterly basis. The plain statement of the outcome is in DOW-UAP-D100, a November 1948 letter from Major General C. P. Cabell, Director of Intelligence: "By letter dated 30 December 1947 from the Director of Research and Development, Headquarters USAF, your Headquarters was required to establish Project 'SIGN'." That is where Project Sign's 1948 paperwork picks up. Cabell's letter shows headquarters still circling a year on: "The conclusion appears inescapable that some type of flying object has been observed." And on the press: "Silence on our part will not long be acceptable."
The FBI's Twining, a month earlier
The Bureau's disc file has its own Twining reference, and it points the other way. In UFOP-6b3bb58a, section 3 of FBI file 62-HQ-83894, an August 1947 memo from D. M. Ladd to the Director relays what the Portland office learned about two AAF officers, Captain Davidson and Lieutenant Brown, interviewing disc witnesses in Oregon. The Oregonian's aviation editor, Richards, wanted to know why, so he "contacted Major General Twining of Wright Field, Ohio, and from him gained the impression that the AAF instituted this investigation to wash out the disc reports since they are definitely not of AAF origin." The same memo records that the two officers were killed when their plane crashed at Kelso, Washington on 1 August, and that Bureau investigation found the plane "was definitely not carrying parts of a disc."
That is an impression, formed by a reporter, relayed through a field office, two steps from anything Twining wrote. Still, the archive holds both. In August the Bureau was told a newspaperman had come away from Twining thinking the AAF meant to wash the reports out. In September the same general signs an internal opinion that the phenomenon is "something real and not visionary or fictitious" and asks for a code-named study. The files don't reconcile the two. Probably nobody at the time thought they needed to. More of the Bureau's material is grouped under FBI UAP files.
The rest of the folder
UFOP-f8bfdc1e is a correspondence file, and the other papers are half its value. Fourth Air Force forwarded photographs from Mrs. Mary L. Herren of Portland, taken between 5 and 12 November 1946 near Jefferson, Oregon, already suspecting a defective camera or film. Headquarters replied in December 1947 that the marks were believed to be defects in the film, paper, or camera, and asked that no further investigation be made. A woman in Santa Fe, Mrs. Merchant, told Brig. General Brentnall that the discs were being fired at the United States from a laboratory in Central Mexico run by the Russians. Brentnall said it was not an engineering matter, and by 22 October headquarters recommended no action and closing the case. On 18 November AMC forwarded newspaper clippings about weapons supposedly developed in Spain, noting that the German scientists at its headquarters said no important German scientists were working there. Six days later it asked that the letter be stamped "secret."
The file reads like an office deciding, week by week, how seriously to take its own subject.
In the extracted text, the first copy of the memo comes through nearly clean. The second breaks down partway through paragraph 2 and recovers in time for paragraph 4 and the signature block. Notes on that kind of OCR damage are in how to read these documents, and the era's other saucer paperwork is under disc and saucer sightings. The original PDF is linked from the UFOP-f8bfdc1e page, which is where any quote here should be checked.