Spring 2021 Cadet AirCorps Museum AT-10 Wichita Restoration Update

At the end of WWII, the USAAF had thousands of surplus airplanes on its hands. The task of disposing of or selling those planes was enormous.

Some could be profitably sold to foreign air forces. Other surplus aircraft were useful in a civilian role. For example, thousands of surplus C-47s would become a mainstay of civilian companies that flew cargo and passengers for many years after the war. Some still are earning their keep with commercial operators to this day.

Other aircraft had less utility as civilian planes. The AT-10, with a limited useful load and fairly high operating cost was one of these. 2,371 AT-10s were produced by Beech and Globe. In 1946, the War Assets Administration listed 1,930 of them for sale at various locations around the country. 80% of the entire production of Wichitas was on the block as surplus. The only AAF plane with more examples on surplus sale listings in 1946 was the Vultee BT-13 (4,280).¹

^{1 William Larkin, Surplus WWII U.S. Aircraft, BAC Publishers, Inc.; 1st edition (December 1, 2005)}

Many of the AT-10s that were eventually purchased were bought for their engines.

In 1942 an AT-10 cost the government $42,688, by the time they were sold as surplus the price was less than $1,500 and many were bought for their Lycoming R-680-9 engines that were suitable for use in surplus Stearmans that were being used as crop dusters. At 295 horsepower, the Lycoming was also a performance upgrade to PT- 13s that had similar R-680s which were rated at a lower 220 horsepower. Most often the engines, and other usable parts of the AT-10s were removed, and the rest of the wooden airframe was left to weather away to just the aluminum components of the cockpits and nacelles.

The other significant reason for the lack of survivors is that despite the forward fuselage and engine nacelles being made of aluminum, the bulk of the aircraft, even the fuel tanks, was made of plywood. Plywood was a non-strategic material, which made construction of the AT-10 possible at a time when aluminum was in high demand for combat aircraft, and its lightness contributed greatly to the AT-10’s superior performance. However, plywood doesn’t fare well for long periods outdoors, so the aircraft remaining at the end of WWII quickly succumbed to the elements. Barely a handful made it onto the civil registry.

Only one intact Wichita remains. It is on display at the National Museum of the United States Air Force and is on static display only. Once completed, AirCorps Aviation’s AT-10 restoration will become the only flying example of an AT-10 in the world.

“Durawood” is called out in many AT-10 drawings and mentioned in manuals, and figuring out what it was and how to replicate it was one of the challenges of the AT-10 project. After much research, it was determined that Durawood was a material composed of many layers of 1/32 inch thick walnut, laminated together with resorcinol glue. Once cured, it is stronger than a block of wood and was used in stress points and where major components were bolted together.

After the bulkheads and formers were mounted in the fixtures, the longerons had to be formed and installed. They have some complex tapers and bevels.

One of the identifying characteristics of the AT-10 is the porthole shaped windows just aft of the cockpit.

The skin on the AT-10 is 1/8th inch thick, 3 ply mahogany and poplar plywood. In many areas it must be steamed or soaked in ammonia to make it pliable enough to conform to curved fuselage sections.

The next step was to attach the forward cockpit area and the vertical fin to the main wooden fuselage.