AirCorps Aviation of Bemidji, Minnesota has just announced that they have acquired a massive trove of original manufacturing drawings for North American Aviation (NAA) covering types such as the P-51, T-6, B-25 and P-82. This is a remarkable development, and all due to a lone engineer at NAA named Ken Jungeberg who had the foresight to save these drawings when they were days away from destruction at North American’s plant in Columbus, Ohio during the late 1980s. But before we discuss this find, it is perhaps first worth reflecting upon what it represents…

Just a few of the thousands of WWII-era North American Aviation aircraft manufacturing drawings which Ken Jungeberg saved. (image via AirCorps Aviation)

The American aircraft industry produced just under 300,000 aircraft between 1940 and 1945, a staggering feat by any measure, especially considering that just 3,600 rolled off U.S. assembly lines during the entirety of 1940. While aviation companies such as Boeing, Douglas, Curtiss and their like would design the aircraft, and put them together at their factories, it was simply impossible for them to both make all of the components and subassemblies on site and keep up with production demand. They had to subcontract out the bulk of this work once a design received an order for full-scale production. Indeed, much of America’s entire manufacturing base was involved in this effort – from small ma and pa furniture shops to industrial giants like Ford and Chrysler – whether they were making map cases or wing panels. Some companies, such as Ford, even had their own aircraft assembly lines, like the one in Willow Run, Michigan which built B-24 Liberators.

But have you ever wondered how it was possible to have such a prolific output of high quality aerial machinery when each aircraft assembly line received component parts from so many different independent subcontractors? How was it possible for all of those many thousands of parts to fit together properly in such a repeatable fashion?

The answer is pretty simple; it all came down to the quality of the manufacturing drawings which the aircraft company engineers created during their design process. If you had a coherent set of accurate drawings showing how to make each part, and how to put each assembly together, then you could rely upon skilled workers at disparate factory locations to produce components whose dimensions complied with design tolerances. Of course, there were times when problems arose, but when they did, the engineers usually found solutions. But a coherent set of manufacturing drawings was key to this effort.

However, every single component, from the tiniest rivet to the entire aircraft, required drawings to properly describe them. Obviously, the more complex parts and sub-assemblies required multiple drawings, sometimes hundreds. Highly skilled draftsmen and women created all of these drawings by hand by – usually using pencil on vellum drafting paper. Drawings could sometimes be massive too, extending ten feet or more. The finished product was designed to be practical, fully describing the part and how it fit into an assembly. Drawings were often exquisitely beautiful too – more works of art than simply functional. //

But then along came AirCorps Aviation with their AirCorps Library project. For a small annual subscription of just $50, you have access to serious engineering details, including manuals, for several dozen American WWII-era aircraft designs. They have also digitized the engineering drawings for a number of these aircraft too, such as the P-51 Mustang, F4U Corsair and B-17 Flying Fortress. While they haven’t digitized everything available yet for each aircraft design – it’s a massive process – it is a fascinating resource for anyone with even a passing interest in WWII aviation. //

This is why the news about the preservation of more than 15,000 original drawings produced by North American Aviation that relate to such iconic designs as the T-6 Texan, P-51 Mustang and B-25 Mitchell is such a revelation. AirCorps Aviation has gained access to these drawings, and is presently cataloguing and copying them for their subscription library. However, the fact that these drawing still exist at all is down to the dedicated efforts of just one man, Ken Jungeberg. His name will resonate in aviation lore for generations to come due to his foresight in saving such historically important documents. For further details on this remarkable news, we will let AirCorps Aviation’s Ester Aube continue the story…