The L-4 “Grasshopper” was the military version of the popular Piper J-3 Cub first introduced in 1938. Essentially the same aircraft, windows were added to the aft cabin of the J-3 to improve visibility, and the typically yellow Cub was painted olive drab. The L-4 was originally designated the O-59 when in 1942 the Secretary of War ordered the designation Observation changed to Liaison.

The U.S. Army Air Forces (AAF) ordered the first O-59s in 1941 for tests in conjunction with the military’s growing interest in the use of light aircraft for liaison and observation duties in direct support of ground forces. The L-4 was the first aircraft mass produced for this use. Between 1941 and 1945, the AAF procured 6,066 copies of the militarized J-3 and variants, of which 5,453 were L-4 models and 100 were AE-1 Air Ambulance versions of the J-5.

During WWII, “Grasshoppers” performed a wide variety of functions throughout the world such as for artillery fire direction, pilot training, medical evacuation, courier service, and front-line liaison. Members of the Civil Air Patrol flew thousands of hours in light planes such as the L-4 searching for enemy submarines in U.S. coastal waters. Piper was based in Lock Haven, Pennsylvania.


Wingspan: 35 ft 3 in
Length: 22 ft 5 in
Height: 6 ft 8 in
Empty weight: 640–765 lb
Useful load: 455 lb
Gross weight: 1,160 lb
Payload: 340 lb
Wing area: 178.5 sf
Armament: None
Engine: 65 hp Continental O-170-3 (military designation) / Continental A-65-8
Oil capacity: 4 qt
Fuel capacity: 12 gal
Crew: 2 (pilot and observer/passenger)
Cost: $2,600


Cruise speed (IAS): 75 mph
Max. dive speed: 130 mph
Stall speed, power on: 35 mph
Range: 190–260 mi
Takeoff distance (over 50-foot obstacle): 730 ft
Landing distance (over 50-foot obstacle): 470 ft
Rate of climb: 600 fpm
Service ceiling: 11,000 ft
Wing loading: 6.84 lb/sf
Fuel consumption: 4–5 gph

L-4 flying lead with ALS formation over San Antonio, Texas, following a ceremonial flyover at Ft. Sam Houston, November 2014.
The Classic Piper Cub. In November of 1937 William T. Piper introduced to the industry the Piper Cub – an aircraft destined to become one of the most recognizable personal transport icons in the world.

Watch the extended version of The Classic Piper Cub on YouTube here.

Piper L-4 “Grasshopper” at the National Museum of the United States Air Force, Dayton, OH. (U.S. Air Force photo)
1943 Piper L-4B owned Richard Kriegsman, fitted with Brody Device. Learn about L-bird pilot John Kriegsman and see the Brody Device in action here.
Squadron leader Gene Jenson returns to Cannon Field in his L-4 “Just The Bear Necessities” over the San Antonio skyline, 2015.

The Mighty L-4

Though classified as a “light” aircraft and derided as a warbird, the L-4 was well regarded on the battlefield among Army officers as a mighty aircraft, a giant and indispensible. Excerpts from Ken Wakefield’s The Other Ninth Air Force:

Lt Col. Leich, accompanied by Lt Bovan, Tech Supply Officer, 50th MR&RS, departed ‘in a mighty L-4H‘ for A-42C Villacoublay to discuss supply matters with 2nd AADA and to meet Major Lefever (Arty Air Officer, 12th Army Gp), Major Wilson (Third Army Arty Air Officer), Major Bristol (First Army Arty Air Officer) and Lt Mathews. Time en route was 4 hours.

Major Bristol, Arty Air Officer First Army, forwarded message from 12th Army Gp that five ‘Giants’ [L-4Hs] for Ninth Army were at A-92 St Trond/Brusthem. Lt Mathews and four borrowed pilots went by truck to A-92, but the aircraft had not yet been delivered from Paris.

EAGLE (Sgt Hogan, Air Section) called to say that five ‘Giants’ [L-4Hs] Will arrive at A-92 St Trond before 1500 hrs today. He added that the 84th Div aircraft shipped from the US were not L-5s, as alleged, but were L-4Hs.

Army HQ reported that a number of Stinson L-5s were to be expected in the near future as replacements for L-4s… Arty Air Officers and other pilots were opposed to the introduction of the L-5 for Air OP work, the lighter L-4 being preferred because of its better short field performance and its ability to operate from very rough, unprepared strips. The less complex L-4 was also preferred from an ‘in the field’ repair and maintenance viewpoint.

Shot Down

Despite their small size and “non-combat” construction, the mighty L-4s experienced numerous incidents L-4 being shot down. In one month alone, March 1945, the Ninth U.S. Army reported the loss of nineteen of their 300 L-4s, eight of them being destroyed by enemy fighter aircraft.

Note: The L-4F and L-4G, built in 1951, were based on the 3-seat Piper J-5. While the J-5 had previously been used for the AE-1/HE-1 Air Ambulance, the L-4F and L-4G were not ambulance versions.