The U.S. armed forces procured several thousand light observation/liaison aircraft beginning at the start of World War II. Known colloquially as “grasshoppers,” a few hundred were flown by the Navy and (mostly) the Marine Corps.
These were single-engine, high-wing, two-place aircraft, initially developed from commercial designs. Operating from rough, grass fields as well as airfield runways, the planes were employed in a variety of roles: observation, liaison, artillery-fire spotting, casualty evacuation, and “taxi.” In addition, with engines removed and other modifications, they also were used for glider-pilot training.
The most numerous model acquired for the sea services was the Convair OY-1. The Army flew several thousand as the L-5 series, with 306 of the L-5B/E variants going to the Navy and Marine Corps during World War II. These aircraft were designated OY—the “O” indicating observation and “Y” the symbol for Convair, which was created in 1943 by the merger of the Consolidated and Vultee companies.1
The Navy and Marine Corps acquired additional types of grasshoppers: the HE-1 for casualty evacuation, which could carry a litter patient plus the pilot (changed to AE-1 when the prefix letter “H” was assigned to helicopters); the NE-1 training aircraft; the CQ-1, with records indicating that the Navy procured only one of these; and the XLNP-1, with three of these engineless aircraft acquired for glider-pilot training.
The OY-1s were flown mainly by the Marines. The first grasshopper squadron was Marine Observation Squadron (VMO) 155, established on 27 October 1943 at Quantico, Virginia.More squadrons quickly followed. They went into action spotting for artillery in the assault on the Mariana Islands in June 1944—VMO-2 and VMO-4 during the Battle of Saipan, flying ashore from escort carriers (CVEs). The subsequent assault of nearby Guam found grasshoppers from VMO-1—as VMO-155 was redesignated on 7 January 1944—also coming ashore from CVEs.
Marine OY-1s continued to operate with Marine troops ashore, on Peleliu, in the Philippines, on Iwo Jima, and on Okinawa. On a few occasions Marine grasshoppers mounted bazooka rocket launchers on their wing struts—the only armament believed to have been fitted to the aircraft, although other field innovations may have been made.
In 1948 most of the surviving Navy-Marine OY-1s were given updated, 24-volt electrical systems and were changed to OY-2. In 1951–53 the Navy procured 60 upgraded grasshoppers, designated OE-1, from Cessna and two more in 1959; 27 more with upgraded engines were acquired as OE-2 in 1955–56. These were similar to the Army’s L-19, with several of that service’s aircraft having been borrowed earlier to equip VMO-6 when it began combat operations in Korea in August 1950.
OY-1s proved outstanding in many roles under arduous climate and combat conditions. And on several occasions, Marine and Army aircraft flew from “aircraft carriers”—modified tank landing ships (LSTs). (These ships and their operations will be described in “Historic Aircraft” in the March-April 2014 issue of Naval History.)
The widely flown L-5/OY series had its origins in the pre–World War II Stinson HW-75, a civilian aircraft first flown in 1939. It was easy to fly and reliable and had short-field capabilities. Stinson became a division of the Vultee Corporation in 1939, and the aircraft was evaluated the following year by the Army. The design was modified extensively to service standards. Following the prototype’s impressive performance, from December 1942 to September 1945, Convair produced 3,608 tandem-seat L-5/OY aircraft.
The fuselage was fabricated of chrome-moly steel tubing with the wings and empennage made of spruce spars and plywood ribs; cotton fabric was used to cover the fuselage and wings. Aluminum was used only in the engine cowling, ailerons, rudder, elevator, and landing-gear fairings. The standard engine was a Lycoming six-cylinder, 190-horsepower O-435.
Beyond being flown by the U.S. armed forces, 16 L-1 grasshoppers were transferred to Great Britain early in the war and another 100 L-5s were built specifically for British service during the war. These were flown mostly in Burma and India. After the war, hundreds were operated by numerous foreign military and police services. (Many grasshoppers were “civilianized” with some being converted to biplanes for crop dusting.)
Marines flew grasshoppers in the Korean and Vietnam wars in large numbers, with the improved OE series being procured. Thus, the little planes—often referred to as “flying jeeps”—made a major contribution to U.S. military operations for three decades. They finally were replaced by helicopters as well as larger aircraft with sophisticated sensors and other capabilities. The last U.S. OY-series grasshoppers were retired from VMO-1 in November 1954; the last OEs—redesignated O-1 in 1962—left the inventory in March 1970.
1. Details of the L-5/OY are found in John Wegg, General Dynamics Aircraft and their Predecessors (Annapolis, MD: Naval Institute Press, 1990), 141–43.