Modified WWII Aircraft: Turboprop Boeing B-17 Flying Fortress Air Tanker

The decades following World War II saw the venerable Boeing B-17 Flying Fortress transition from military service to various civilian roles, one of which was firefighting. In an amusing twist of fate, the legendary bomber that once delivered widespread destruction now dropped fire retardant to save lives and preserve property from the devastation of wildfires.

Among the various repurposed B-17s, one stood out. In an effort to boost reliability and performance while loaded with retardant and flying among dangerous downdrafts among wildfires, the original piston radial engines were replaced with Rolls-Royce Dart turboprops in 1970. Each Dart provided 50% more horsepower and was 500 pounds lighter than the original Wright Cyclones they replaced.

Had the new, lighter engines been positioned in the same place as the original engines, the aircraft’s center of gravity would have shifted too far rearward. Accordingly, each engine was positioned roughly three feet forward to maintain the B-17’s original center of gravity and flight characteristics.

The converted aircraft had so much power that pilots were reportedly able to shut down both outer engines and still fly faster than an unmodified B-17, even when loaded with fire retardant. It was briefly used for aerial firefighting in 1970 but was tragically destroyed in a crash later that year.