The frame of a Stearman PT-13D Kaydet aircraft sits in the Restoration Hangar

Restoring a piece of history

By Ken LaRock
National Museum of the U.S. Air Force

The Restoration Division at the National Museum of the U.S. Air Force is currently restoring a Stearman PT-13D Kaydet aircraft, a standard primary trainer flown by the U.S. and several Allied nations during the late 1930s and World War II. Plans call for this PT-13D to be part of an expanded Tuskegee Airman exhibit in the World War II Gallery to represent flight training during the war.

Restoration specialist sprays protective coating on aircraft.
National Museum of the U.S. Air Force restoration specialist Brian Lindamood applies aluminized cellulose nitrate dope to the Stearman PT-13D Kaydet. This paint serves as a UV protectant which keeps the fabric from deteriorating. Plans call for the aircraft to be part of an expanded Tuskegee Airman exhibit in the World War II Gallery at the National Museum of the U.S. Air Force. (U.S. Air Force photo by Ken LaRock/Released)

“A lot of people learned how to fly in this airplane,” said Casey Simmons, a restoration specialist at the museum who has been working on this project. “Many of the aircraft were built in the 1930s and ’40s to support the war effort.”

Of the more than 10,000 Kaydets ordered for the United States and its Allies, over 2,100 were PT-13s for the U.S. Army Air Force.

Simmons developed a fascination for aircraft in childhood and began working for the museum in October 2007.

“This is a lot of fun because I built these model kits when I was younger, and now this is the real thing,” Simmons said. “Your little balsa wood and fabric kits that you build; it’s pretty much the same process. It’s a lot of fun to take apart what they have done, and you can see how they did something, how they folded a piece of fabric or how they sewed it, and recreate it the exact same way.”

He described the unique process involved in this particular restoration.

“To start with, we had to take all the old fabric off, and we had to clean up the frames and structure and put varnish back on, so the wood is all prepared for fabric,” he said. “Then you have to sew up envelopes that are like pillow cases that are in the shape of the wing, and you have to pull them on. Next, you stitch together all the seams for the corners of the wings, then you rib stitch the wings to hold the fabric to the wing itself. After that you start applying the finishes, which is about nine coats total. In fabric, a coat is actually two applications, so you’re talking about 18 times you have to apply the material.”

Aircraft dope is a plasticized lacquer used to tighten and stiffen the fabric that is stretched over the airframe. It helps to weatherproof the aircraft and make the cotton airtight. Simmons geared up with protective mask and gloves before applying a coat of the aircraft dope to finishing tapes. Holding a paint can, he used a brush to fill the weave of the fabric to get everything glassy smooth. The aircraft grade cotton used for the wings was obtained from Europe.

Though Simmons received mostly sheet metal training, he appreciates the early aircraft assembly processes.

“Airplanes we work with now are mainly sheet metal, so you learn all those skills like how to buck rivets and lay the sheets over each other,” he said. “Well, this is a completely different process. You learn a little bit of it when you’re in A&P [Airframe and Powerplant] school to become an aircraft mechanic. But a lot of it is hands-on learning as you go, learning how the seams are supposed to be sewn and how to pull the envelopes on.”

“It’s a real enjoyment to see it from the shape it was in, taking it to where it looks brand new, and knowing that it’s done right,” Simmons said. “Everybody has to do their own part — someone is sewing, somebody is applying the finishes, and somebody is attending to the wooden parts. You put a lot of hard work into it, and you know your product is good when you’re done.”

Simmons’ gratification is seeing people’s reaction to the completed work.

“To see somebody who it really means something to them, and that it takes them back to when they were younger, you can see how they feel and it makes you feel great.”

A few months remain until Simmons will enjoy visitors’ reactions to the completed PT-13D. A silver color coat must still be applied, as well as markings and insignias on the left wings and other surfaces that are in the paint booth. When that painting is complete, the restoration staff will move on to restoring the wood prop and prepping the fuselage for fabric. The fabric will be measured, cut and sewn onto the fuselage, then moved to the paint booth, and along with the right side wings, they will stitch the wing ribs, apply the dope coatings and finishing tapes, and then spray UV aluminum and silver color coats, followed by markings and insignia. At last, the aircraft will be assembled and placed on display.

In the meantime, visitors can take a guided tour of the restoration facility by signing up for the museum’s Behind the Scenes Tour offered every Friday throughout the year (with some exceptions). For more information, visit www.nationalmuseum.af.mil/visit/tours.asp.