"Lil Bill" at Planes of Fame Museum. The military L-17 Navion started as the civilian 185hp NA145 model. It bore some resemblance to the P-51D, but had a tricycle landing gear. The USAAF became interested in 1946 and ordered 83 for observation, liaison and as trainers for ROTC, plus six as unmanned drones. Ryan Aircraft acquired manufacturing rights in 1947, delivering the L-17B and L-17C. In 1960, TUSCO acquired rights and made the L-17. By the time production ended, around 2,500 had been built.