The Piper Aircraft Company, like several other lightplane manufacturers, submitted a liaison version of their tandem trainer to the military. The result was a large contract for the L-4 (commonly called “The Grasshopper”). Essentially, the L-4 was identical to the prewar 65 hp Continental-powered J-3 Cub, with some changes made to the instrument panel, to its interior, and, most obviously, to the amount of glass area surrounding its cockpit. The adaptable Grasshopper was used for many unusual tests. There was at least one ocean-going ship converted to a liaison aircraft carrier! It was used to take L-4’s near the beachhead on D-day, where they could take off for the coast and go right to work, flying missions to and from the beaches. The L-4 was the primary liaison aircraft in the European Theater of Operations, helping to prove the usefulness and ruggedness of this intrepid light airplane in military combat applications.