Dating back to a 1930 design called the Taylor Cub, the Piper J-3 Cub design was vastly popular as a civilian trainer and sport plane for at least three years before the US Army Air Corps selected the aircraft to be evaluated as an artillery spotter/director platform. The first J-3s delivered, powered by a 50-hp Lenape Papoose 3-cylinder radial engine, were designated the O-59. 40 were delivered in 1941. Shortly thereafter, the Army ordered a new version powered by a 65-hp Continental O-170-3 flat-four engine. It was originally designated the O-59A, but due to an Army designation change, it was called the L-4A. 948 were eventually delivered, and the nickname "Grasshopper" was almost immediately applied.
Subsequent variants included the L-4B, with reduced radio equipment and a 65-hp Continental engine; the L-4H, which was almost the same as the B-Model; the L-4J, with a variable-pitch propeller; and the L-4C and L-4D, both of which were actually civilian J-3 models pressed into service at the beginning of WWII. The US Navy also purchased 250 Cubs for use as trainers, which they designated NE-1s (and later, NE-2s.)