Modified from the Piper J-3 Cub, the L-4 was a light observation and liaison aircraft adapted for military use during World War II. Its primary role was coordinating long-range artillery fire for Allied forces. This activity required the L-4 to fly over battlefields, observe, spot enemy artillery and troop positions, and radio the information to Allied ground forces who then directed artillery or air strikes on the enemy. These aircraft served in all theaters of World War II, as well as in both the Korean and Vietnam Wars.
L-4s operated out of Hill Field during World War II. After the war, starting in 1949, the L-4 was among the many aircraft that the men and women of Hill Air Force Base repaired and modified.
The L-4J on display served in the Fifteenth Air Force in Bari, Italy, beginning in 1945. That same year, the aircraft returned to the United States and served on several different bases in support of flight training. Due to a flying accident in 1952, the US Air Force dropped this aircraft from their inventory, and it was later acquired by the Hill Aerospace Museum for display.
This aircraft is a part of the USAF Heritage Program collection
Serial Number: 45-4655
Manufacturer: Piper Aircraft, Inc.
Primary Function: Personnel Transport and Reconnaissance
Crew: One or two
Engines: One Continental A65 four-cylinder reciprocating; 65 hp
Wingspan: 35 ft 3 in
Length: 22 ft 5 in
Height: 6 ft 8 in
Weight: 680 lbs (empty); 1,200 pounds (maximum takeoff weight)
Speed: 75 mph (cruising); 85 mph (maximum)
Range: 190 miles
Service Ceiling: 11,500 feet
Armament: None
Cost: $2,600
Years of Service: 1941 – 1950s
In 1949, the L-4s were among the many aircraft that were repaired and modified at Hill Air Force Base. A few years late, they were stored on the installation after the Korean War. The L-4J on display was manufactured in 1945 and served the 15th Air Force in Bari, Italy. That same year, the aircraft returned to the United States (US) and served on several different bases and training commands. Due to a flying accident in 1952, the aircraft was dropped from active US Air Force inventory and was later acquired by Hill Aerospace Museum for display.
The L-4 Grasshopper was a military adaptation of the popular Piper J-3 Cub, modified for service during World War II. Light, nimble and easy to operate, it served as a liaison and observation aircraft for Allied forces across every theater of the war. Later variants of the L-4 also served in both the Korean and Vietnam Wars.
The Grasshopper’s primary job was coordinating artillery fire for Allied ground forces. Pilots flew low over battlefields, spotted enemy artillery and troop positions, then radioed the intelligence to ground commanders who directed artillery or air strikes on the targets. It also served in liaison and medical evacuation roles throughout the war.
Small, slow and built to operate from any open field, the L-4 and its fellow light liaison aircraft earned the “Grasshopper” nickname during World War II for good reason. These little planes hopped low over battlefields from one makeshift landing strip to the next, doing the work that faster, more powerful aircraft simply couldn’t.
The L-4 started life as a Piper J-3 Cub but was modified specifically for military use. The most notable change was the addition of enlarged rear windows to give the observer a clear downward view of the battlefield below. This was essential for the artillery spotting work that made the Grasshopper so valuable to Allied commanders!
Although the L-4 was designed as an unarmed observation aircraft, some pilots famously field-modified their Grasshoppers with wing-mounted bazookas to successfully engage enemy armor. This improvised innovation gave the little Cub an extra combat punch and a permanent place in WWII legend.
The US military produced thousands of L-4s during World War II to meet the demands of a doctrine that required eyes over the battlefield at all times. At just $2,600 per aircraft, the Grasshopper was purpose-built for cost-effective mass deployment. Its low cost made it practical to station across every theater of the war simultaneously.
L-4 Grasshoppers flew out of Hill Field (the base’s wartime designation) during World War II. After the war, starting in 1949, Hill Air Force Base became a center for repairing and modifying L-4s and other light aircraft. Over the years, maintenance crews kept the aging Grasshopper fleet mission-ready for the Air National Guard and Air Force Reserve.
Built in 1946 as a civilian Piper J-3C Cub trainer, this aircraft was restored in 1991 to represent the iconic L-4J Grasshopper of World War II. After decades of private ownership, the museum’s supporting foundation acquired it from Idaho’s Snake River Maintenance Company in 2000.
Today it’s painted to represent an L-4 that served with the 15th Air Force in Bari, Italy—one of the unarmed spotter planes that flew low-altitude missions over the front lines, providing reconnaissance for Allied forces.
