The L version of the P38 is an excellent example of how improvements of a model over time can really pay off. With the addition of Hydraulic ailerons, and Dive flaps, Lockheed solved the main problem of the P38L: Control lockup at high speed. An improved propeller helped with speed and climb over the P38F. While the P38F becomes a high-speed lawn dart at speeds greater than 375, the P38L can be dived to speeds in excess of 500mph IAS with minimal degradation in controls. Thus Lockheed took what was a mediocre combat plane and turned it into a trained killer, and an excellent energy fighter.