USAF Engineering Division Finding Aid Background
Records of the US Air Force Engineering Division Held by the US National Archives


Since 1917, nearly all research and development activities required to equip the US Air Force and its predecessors (US Army Air Corps, US Army Air Force) with aircraft, engines, propellers and equipment was conducted or managed by the Engineering Division of the US Air Force Material Command. These ongoing R&D efforts produced a voluminous collection of data in three forms:
  1. Central Decimal Correspondence Files (also called the "Sarah Clark File"), 1917-1951, which consists of incoming and outgoing letters, memoranda, messages, reports and other like material relating to R&D activities; and
  2. R&D Project Case Files, 1921-1953, created by various laboratories and units of the Engineering Division and consisting of studies, test reports, technical instructions, drawings, photographs, project record books, and the like.
  3. Microfilmed Memorandum Reports, originally part of the R&D Project Case Files described above.

Collectively, these files document the beginnings of aeronautical development in the US and represent the investment of billions of dollars on aerospace technology.

In the 1960s, a change in Air Force records management policy resulted in the collection being broken up and moved from Dayton, Ohio to several Federal Record Centers. Many of the files eventually found a permanent home at the National Archives II (hereafter "Archives") at College Park, Maryland; the remainder wound up at the St. Louis Federal Records Center (now The National Personnel Records Center). There a 1973 fire destroyed some Engineering Division Records; the remainder remain unaccessioned, uncataloged, and for all practical purposes, unavialable to the public.

These documents, drawings, photographs and microfilms that comprise the Engineering Division records at Archives II occupy more than a mile of shelf space.

AEHS researchers have made extensive use of the Correspondence Files and found it to be an extremely valuable resource for all things related to the development of Air Force equipment. The R & D Project Case Files complement the Correspondence Files by providing many of the actual reports, drawings, photographs and charts mentioned in the correspondence.

Together, the Correspondence and R&D Project Case Files constitute what is probably the single most important resource in the US, perhaps in the world, for the study of the history of aircraft technology. This is the real stuff — the actual day-by-day record of the Engineering Division's activities. It is full of technical detail and rich with accounts of innovation. It is the kind of source material that forms a basis for serious study of US Air Force materiel development prior to 1950.

AEHS researchers have only scratched the surface of what is there, but the things we have seen are simply astounding. They include: records of meetings and conferences that give broad overviews of technology, philosophies, politics and policies; memoranda giving account of specific programs and studies; records related to the development of aircraft, engines (reciprocating, gas turbine, pulsejet, ramjet and rocket), propellers, superchargers (both engine driven and turbosuperchargers), magnetos, fuels, lubricants, carburetors and fuel injection; full transcripts of the Truman Committee's investigation of Curtiss-Wright during WWII; inspection reports on captured German and Japanese engines with detailed pictures and analysis of the overall engines and the parts that comprised them; various manuals for specific aircraft, engines, and equipment, and more.

As one might imagine, there is a huge volume of information on well-known engines. There are enough reports and documents on the Packard Merlin alone to fill more than eight filing cabinets, most of it never published. Many believe that Packard simply produced Merlins like popcorn, but this complex program faced many serious issues. There are also thousands of reports that give incredible insight into not-so-well-known engines, allowing one to trace the application of certain "enabling" technologies.

Another amazing discovery is a detailed account of for nearly every airplane ever proposed or built for the Air Force. There are hundreds of boxes filled with project information. For proposed projects there are manufacturers' specifications, drawings, pictures, and proposal evaluators' notebooks, which allow insight into how the winners were picked. For the projects that were funded, there are status reports, flight test reports, type test reports, project final reports, production reports, problem reports, operational reports and other reports that detail the trials and tribulations that are part of any complex development program.

The Problem

Despite the inestimable value of this resource, it has been underutilized because its contents have never been cataloged or publicized. Although there is structure to its organization, that structure is based on a long-extinct filing system — one that has been modified over time by the different handlers and movers. More importantly, any index that relates its organization to specific subjects is long lost, if indeed it ever existed at all. In other words, a researcher cannot visit the Archives and rapidly view a collection of records relating to "P-51 Mustang." Until the AEHS produced and on-line catalog, it literally took years of persistent hard work and a great deal of luck before the many pieces started to fall into place.

Prior to the AEHS catalog, the most complete finding aid consisted of a box of 100 Microfiche cards. On each card are 84 images of shipping documents. Rather than being organized in a useful way (alphabetic by subject, for example) these are arranged in order of the sequential numbers assigned to shipping containers when the documents originally left Wright Patterson Air Force Base. To make matters even worse, documents related to a given subject or program are not necessarily in sequential boxes. This means that researching any subject quite literally involves reading 8,400 Microfiche images in order to identify the boxes that contain information about that subject! Imagine a telephone directory ordered by telephone number and then imagine how useful it would be. The Microfiche finding aid is about as useful as a telephone directory organized by number.

The Solution

This was the sort of problem that cried for a computerized solution in the form of a searchable electronic finding aid  — one that would produce a list of files whose titles contain key words or phrases entered by a researcher. The value of such an electronic finding aid is greatly enhanced because it is available to the public via the Internet. This allows researchers to decide whether information exists at the Archives without making a trip there and allows them to plan their trip in advance, thereby making better use of their time at the Archives.

In January, 2005 the AEHS Board of Directors voted to create a limited version of such an on-line finding aid for the AEHS web site. The AEHS was in a unique position to perform this task because its members have subject expertise that adds considerable value over teams of computer people with no subject expertise. In addition to its obvious research value, the electronic finding aid project reaps several additional benefits:

1) Because of how the collection is organized, the process of extracting engine information has, by default, produced an index of all aviation subjects, not just engines.

2) It supports additional layers of refinement. By making the history of the Engineering Division more easily accessible, more researchers will use the material and will develop additional insight into its content and structure. This in turn will generate new information that can be included in the finding aid.

Since the AEHS could not afford to implement the entire thing, we chose to first implement citations for the Correspondence Files and selected R&D Project Case Files, including the Power Plant Laboratory. (More on how this was done) We hoped this example would inspire other historians, aviation interest groups, corporations and individuals to help fund and/or transcribe the addition of citations for other Engineering Division organizations. This has indeed been the case -- numerous volunteers have entered over 102,000 citations.

Despite our success, much remains to be done, including the entry of records from the following organizations:

US Air Force Engineering Division Organizations that have not yet been included in the Finding Aid:

The Importance of This Project

The AEHS completed its task of cataloging engine-related USAF Engineering Division records in 2008. Since then the Microfilmed Memorandum Reports of the Flight Test Division, Power Plant Laboratory and Propeller Laboratory have been added. It is fair to conclude that results obtained have been far more useful than anyone ever imagined. It has provided numerous academics, historians, modelers and enthusiasts with valuable material upon which to base their work.

As valuable as this earlier cataloging effort has been, the microfilmed memorandum reports may prove to be even more useful. The Flight Test Division, for example, was responsible for flight-testing aircraft, engines, propellers and other equipment from 1929 until the 1960s. The records of these tests were microfilmed by the U.S. Air Force during the early 1970s and original paper copies destroyed, which means that only the microfilmed versions survive. These are stored at the U.S. National Archives and Records Administration (NARA) facility in College Park, Maryland. Over 4,000 reports comprise this large records collection, which is extremely rich in content. In addition to providing conceptual, developmental, testing and operational details of specific aircraft, they also document the development of doctrine, underlying science, materials, processes, procedures, and standards.

Example Flight Test Division Report

The AEHS believes that this on-line finding aid is an extremely important contribution to the field of aviation history. It forms a foundation that the next generation aviation historians can use for their research and can build upon. It is also a valuable resource for modelers and restorers of vintage aircraft.

The AEHS Needs Your Help. What Can You Do?

The AEHS has completed most of the task it set out to do back in January, 2005. In doing so it has developed a proven methodology for converting original data into a searchable on-line database. It is our hope that other individuals, clubs and organizations who are interested in the remaining Engineering Division Organization records will follow the AEHS example. If your organization is interested, please contact the AEHS.

Making important information like this available for free is not free. Here is what you can do to help.


During our work at the Archives, we AEHS researchers have discovered that even "popular" aircraft such as the P-51 and P-47 have never been fully or accurately documented using source material from the Archives. A gigantic amount of history remains to be written (or rewritten). This effort by the AEHS to produce an on-line finding aid will help make writing that history possible.

Below is a small sample of the unbelievable images among the
U.S. Air Force Engineering Division Records at the U.S. National Archives II.