• Published
  • By Greg L. Davis
  • 72nd Air Base Wing Public Affairs

The Piper Aircraft Corporation L-4 “Grasshopper” was a high-wing, single-engine liaison aircraft with tricycle landing gear configuration. The L-4 was an improved version of the highly successful Piper J-3 ‘Cub’ through the addition of a radio and military paint and markings.

Large sales of the L-4 to the Army Air Corps hinged on the service’s desire to evaluate the ‘Cub’ as a potential liaison/artillery spotter aircraft. Piper also pushed hard to meet the military’s interest to have the aircraft evaluated during mobilization maneuvers in 1941 and made a small 40 aircraft sale that were rushed from the production line to ensure availability for this testing. The YO-59s, as they were initially designated, performed well enough in Louisiana during the maneuvers to secure a large military order for the company in 1942.

Tinker Air Force Base undertook basic maintenance, repair and overhaul of the L-4 aircraft on an as-needed basis. Most of the work done here centered on O-series engine overhaul of the Continental O-170 engine, the most common engine used in the aircraft. Between January 1947 and June 1953, 241 L-4s were processed through the maintenance lines in Oklahoma City.

The L-4 first entered combat in 1943 in the North African campaign, according to Tinker History Office documents. Used in all theatres of the war as a liaison, artillery spotter, observation and courier aircraft, the Grasshopper was also modified to become an air-ambulance, as well. The basic airframe was also used for a three-person glider trainer in the U.S. and as a primary pilot screening aircraft.

Many Piper L-4 aircraft were declared surplus and quickly sold off to the public and flight schools. Some Grasshoppers continued to serve with the U.S. Air Force until 1953 and then with the Civil Air Patrol until the late 1960s. A large number of L-4s remain airworthy today due to their simplicity and forgiving flight characteristics.


Manufacturer: Piper

Aircraft type: L-4

Nickname: Grasshopper

Crew: 1-2 (GT-8 had 3)

Power plant: Various horizontally-opposed engines ranging from 40-65 horsepower

In-service dates: 1941-1960s

Number produced: 5,801

Tinker connection: Maintenance, repair and overhaul