|Length:||22 ft 5 in (6.83 m)|
|Wingspan:||35 ft 3 in (10.74 m)|
|Height:||6 ft 8 in (2.03 m)|
|Wing area:||178.5 ft² (16.58 m²)|
|Empty weight:||765 lb (345 kg)|
|Useful load:||455 lb (205 kg)|
|Max. takeoff weight:||1,220 lb (550 kg)|
|Powerplant:||1 × Continental A-65-8 air-cooled horizontally opposed four cylinder, 65 hp (48 kW) at 2,350 rpm|
|Maximum speed:||76 kn (87 mph, 140 km/h)|
|Cruise speed:||65 kn (75 mph, 121 km/h)|
|Range:||191 NM (220 mi, 354 km)|
|Service ceiling:||11,500 ft (3,500 m)|
|Rate of climb:||450 ft/min (2.3 m/s)|
|Wing loading:||6.84 lb/ft² (33.4 kg/m²)|
|Power/mass:||18.75 lb/hp (11.35 kg/kW)|
The Piper Cub quickly became a familiar sight. First Lady Eleanor Roosevelt took a flight in a J-3 Cub, posing for a series of publicity photos to help promote the CPTP. Newsreels and newspapers of the era often featured images of wartime leaders, such as Generals Dwight Eisenhower, George Patton and George Marshall, flying around European battlefields in Piper Cubs. Civilian-owned Cubs joined the war effort as part of the newly formed Civil Air Patrol (CAP), patrolling the Eastern Seaboard and Gulf Coast in a constant search for German U-boats and survivors of U-boat attacks.
Piper developed a military variant (“All we had to do,” Bill Jr. is quoted as saying, “was paint the Cub olive drab to produce a military airplane”), variously designated as the O-59 (1941), L-4 (after April 1942), and NE (U.S. Navy). The L-4 Grasshopper was mechanically identical to the J-3 civilian Cub, but was distinguishable by the use of a Plexiglas greenhouse skylight and rear windows for improved visibility, much like the Taylorcraft L-2 andAeronca L-3 also in use with the US armed forces. Carrying a single pilot and no passenger, the L-4 had a top speed of 85 mph (137 km/h), a cruise speed of 75 mph (121 km/h), a service ceiling of 12,000 ft (3,658 m), a stall speed of 38 mph (61 km/h), an endurance of three hours, and a range of 225 mi (362 km). 5,413 L-4s were produced for U.S. forces, including 250 built for the U.S. Navy under contract as the NE-1 and NE-2.
All L-4 models, as well as similar, tandem-cockpit accommodation aircraft from Aeronca and Taylorcraft, were collectively nicknamed “Grasshoppers”, though the L-4 was almost universally referred to by its civilian designation of Cub. The L-4 was used extensively in World War II for reconnaissance, transporting supplies, artillery spotting duties, and medical evacuation of wounded soldiers. During the Allied invasion of France in June 1944, the L-4’s slow cruising speed and low-level maneuverability — alongside examples of the Auster AOP aircraft occasionally used by the British Army and other Commonwealth forces for the same purposes — made it an ideal observation platform for spotting hidden German tanks, Sturmgeschütz and Jagdpanzer tank destroyers waiting in ambush in the hedgerowed bocage country south of the invasion beaches. For these operations the pilot generally carried both an observer/radio operator and a 25-pound communications radio, a load that often exceeded the plane’s specified weight capacity. After the Allied breakout in France, L-4s were also sometimes equipped with improvised racks, usually in pairs or quartets, of infantrybazookas for ground attack against German armored units. The most famous of these L-4 ground attack planes was Rosie the Rocketeer, piloted by Maj. Charles “Bazooka Charlie” Carpenter, whose six bazooka rocket launchers were credited with eliminating six enemy tanks and several armored cars during its wartime service, especially during the Battle of Arracourt.
After the war, many L-4s were sold as surplus, but a considerable number were retained in service. L-4s sold as surplus in the U.S. were redesignated as J-3s, but often retained their wartime glazing and paint.