The Wichita Eagle reports that restoring the historic airplane has been a 15-year effort. The plan is to run all four of its radial engines Friday, a step that volunteers hope will put it one step closer to its first flight.

The event will be streamed live but won’t be open to the public.

Built in Wichita 70 years ago, the plane was dubbed “Doc” after being assigned to a squadron of eight bombers named for Snow White and the Seven Dwarfs. It was finished too late to fly bombing missions during World War II, though it eventually served as a radar trainer during the Korean War.