They also were trying to produce the most powerful non-jet engine going, which is a difficult technical problem. Parts were magnesium to save weight, which cou

They also were trying to produce the most powerful non-jet engine going, which is a difficult technical problem. Parts were magnesium to save weight, which could get rather excited if some parts broke and the fire started. A small time to bail out before the wing root burned through. The gun technology, pressured hull, ... all were novel. They didn't know it was possible when they committed to building it.