M22 Locust

The M22 Locust was an American light tank developed during World War II specifically for airborne operations, designed to be transported by glider and provide mobile fire support to paratrooper units with its compact size and light weight of approximately 7.4 tonnes.^[1]^[2] Development of the M22 began in late 1941, initiated by the U.S. Army to meet the need for an air-portable armored vehicle capable of deployment via aircraft like the C-54 Skymaster, following collaboration between the Army Air Force, Armored Force, and Ordnance Department.^[1] The design evolved from prototypes designated T9 and T9E1, produced by the Marmon-Herrington Company, with production beginning in April 1943 and the vehicle accepted as the Light Tank M22, classified as limited standard.^[2]^[1]^[3] Although intended for U.S. airborne divisions, the tank was deemed obsolete by December 1944 due to its thin armor and limited firepower against contemporary threats, leading to no combat deployment by American forces.^[2] The M22 featured a three-man crew operating from an open-top turret and hull, with primary armament consisting of a 37 mm M6 low-pressure gun capable of firing 50 rounds, supplemented by a coaxial 7.62 mm (0.30 in) M1919A4 Browning machine gun with 2,500 rounds of ammunition.^[1]^[2] Its armor protection varied from 12 mm to 25 mm in thickness, offering minimal defense against anti-tank weapons or even heavy machine guns, while the vertical volute spring suspension (VVSS) system supported mobility across varied terrain.^[1] Powered by a 162 horsepower Lycoming O-435T six-cylinder air-cooled engine, the tank achieved a top road speed of 56 km/h (35 mph) and an operational range of 177 km, with dimensions of 3.94 m in length, 2.25 m in width, and 1.84 m in height (without the open turret).^[2]^[1] Production ran from April 1943 to February 1944, resulting in 830 units manufactured.^[1] The British Army received 260 examples under Lend-Lease, redesignating it the Locust and modifying some with a Littlejohn adaptor on the main gun for improved anti-armor performance, before assigning them to the 6th Airborne Armoured Reconnaissance Regiment of the 6th Airborne Division.^[2] Its sole major combat action occurred during Operation Varsity on March 24, 1945, when seven Locusts supported the Allied Rhine crossing in Germany, providing reconnaissance and infantry support despite mechanical issues and vulnerability to enemy fire that led to several losses.^[1]^[2] Post-war, surviving units were largely scrapped, though a small number served with the Egyptian Army into the late 1940s.^[2]

Development

Background and requirements

Prior to the United States' entry into World War II, the U.S. Army had shown growing interest in airborne operations, spurred by observations of German paratrooper tactics in the 1940 invasions of the Low Countries and the rapid development of glider-borne assaults. This vulnerability of lightly armed paratroopers without armored support highlighted the need for lightweight, air-transportable vehicles to provide mobile fire support in rapid deployments behind enemy lines. British experiments with gliders in 1940, including requests for collaborative airborne tank designs through the British Air Commission in early 1941, further influenced U.S. efforts to create specialized equipment for airborne forces despite America's initial neutrality.^[1] In response to these needs, the U.S. Army issued specific requirements in May 1941 for an airborne light tank, designated the T9, weighing no more than 7.5 short tons (approximately 6,800 kg) to ensure compatibility with transport aircraft like the Douglas C-54 Skymaster. The design emphasized a compact footprint and low silhouette to facilitate airdrop operations, allowing the tank to be slung beneath the aircraft fuselage with the turret removed for storage inside, thereby minimizing logistical burdens and enabling quick reinforcement of isolated paratrooper units.^[4]^[1] The Infantry Board and Ordnance Department played pivotal roles in defining the T9's purpose, collaborating with the Armored Force and U.S. Army Air Forces to outline a vehicle optimized for infantry support in airborne assaults, prioritizing mobility and ease of air delivery over heavy armor or firepower. This focused on enabling the tank to operate independently until linked up with main forces, without requiring extensive supply lines. As a direct response to these specifications, the tank incorporated a 37 mm main gun for adequate anti-infantry and light vehicle engagement.^[1]^[5] In July 1941, the Ordnance Department awarded an initial contract to the Marmon-Herrington Company to develop the T9 prototype, leveraging the firm's prior experience with lightweight tank designs such as the CTL series for export. This selection followed evaluations of proposals from other manufacturers, emphasizing cost-effectiveness and rapid prototyping to meet the urgent demands of expanding airborne capabilities.^[4]^[6]

Design and production

The design of the M22 Locust originated with the T9 prototype, developed by Marmon-Herrington starting in late 1941, following a U.S. Army contract awarded in July 1941 and influenced by British requests.^[1] This initial version featured a basic riveted hull and mechanical turret traverse, but subsequent iterations addressed production and transport needs.^[1] The refined T9E1 variant, also completed in 1942, introduced key engineering enhancements including a welded hull for improved structural integrity, rubber-block tracks to enhance traction and reduce noise, and a hydraulic turret traverse mechanism for smoother operation.^[1] Central to the design was the turret's quick-release mounting system, allowing removal in under 10 minutes to fit within aircraft cargo limits, alongside compact dimensions of 3.94 m in length, 2.25 m in width, and 1.84 m in height.^[1] An initial development contract was awarded in 1941, with pilot models tested in 1942; full production began in April 1943, with 830 units manufactured by Marmon-Herrington until February 1944. Of these, 260 were supplied to Britain via Lend-Lease for airborne use, incorporating features like the British No. 19 radio set for standardized communications.^[1]

Testing and evaluation

The U.S. Army initiated testing of the T9E1 prototypes, precursors to the M22 Locust, at Aberdeen Proving Ground in December 1942, with evaluations continuing into 1943 to assess durability, reliability, and overall performance.^[1] These trials included airdrop simulations, where the vehicle demonstrated compatibility with the C-54 Skymaster aircraft for parachute deployment when the turret was removed. In February 1943, the prototypes were transferred to the Armored Force for further field assessments, revealing issues with the transmission and powertrain.^[1] Mobility evaluations during these tests highlighted the vehicle's capabilities on varied terrains, achieving a top speed of 64 km/h (40 mph) on roads due to its 162 hp Lycoming O-435 engine and lightweight 7.5-ton design.^[7] It successfully climbed gradients up to 50% and crossed trenches 1.68 m wide, but performance faltered on steeper slopes exceeding 30 degrees and rough off-road conditions, attributed to a suboptimal power-to-weight ratio that limited acceleration and hill-climbing under load.^[1] Several mechanical shortcomings were identified, including unreliable engine cooling that led to overheating during extended operations, frequent track shedding on uneven ground, and constrained internal space resulting in only 50 rounds of ammunition storage for the 37 mm M6 gun.^[1] A September 1943 preliminary report from the U.S. Army Armored Board at Fort Knox deemed the T9E1 unsatisfactory overall, citing inadequate reliability, armor protection, and combat effectiveness, though it acknowledged potential for airborne roles with modifications.^[1] British evaluations of the second T9E1 prototype began in late 1942 upon its shipment to England, with more extensive trials in 1943–1944 focusing on integration with the General Aircraft GAL.49 Hamilcar glider and operational suitability.^[1] These tests confirmed similar faults in mechanical reliability but prompted minor modifications, such as improved periscopes for better visibility and a Littlejohn adaptor for the main gun to enhance penetration.^[1] Despite persistent flaws, the British accepted the design in 1944 for urgent airborne requirements, designating it the Locust and prioritizing production for reconnaissance units.^[1]

Design characteristics

Chassis and mobility

The M22 Locust employed a welded chassis constructed from rolled homogeneous steel plates, forming a compact hull that accommodated a crew of three: the driver positioned in the forward left hull, the gunner on the left side of the turret, and the commander serving as loader on the right side of the turret. This internal layout optimized space in the confined 12-foot-11-inch-long vehicle, with the driver's compartment featuring a sloped front glacis plate that enhanced ergonomics by providing deflection angles while maintaining visibility through periscopes and vision ports.^[3] The suspension system consisted of a vertical volute spring setup (VVSS) with four small road wheels per side arranged in two bogies, supplemented by two return rollers, a 22-tooth front drive sprocket, and a trailing adjustable idler with volute springs. This configuration supported the tank's 7.5-ton combat weight while ensuring stability and ease of maintenance during airborne operations.^[3] Power was supplied by a rear-mounted Lycoming O-435T six-cylinder horizontally opposed air-cooled gasoline engine, producing 162 net horsepower at 2,800 rpm (with a gross output of 192 hp). The engine drove a four-speed manual transmission and controlled differential steering, with a fuel capacity of 57 US gallons enabling a road range of about 110 miles at a top speed of 35 mph.^[3] Mobility characteristics included a low ground pressure of 7.1 psi for effective cross-country performance, a fording depth of 36 inches, a vertical obstacle climb of 18 inches, and a trench-crossing capability of 66 inches. The chassis design facilitated rapid disassembly into major components for air transport via glider or aircraft, with production models incorporating transport adaptations such as removable transmission assemblies to expedite loading.^[3]

Armament and protection

The M22 Locust was equipped with a primary armament of a 37 mm Gun M6 mounted in the M53 mount within a small, open-top turret. This gun, weighing 84 kg and measuring 2.1 m in length, was capable of firing a variety of ammunition types, including armor-piercing (AP M74), armor-piercing capped (APC M51), high-explosive (HE M63), and canister (M2) rounds, with a total capacity of 50 projectiles stored in the turret and hull. The weapon had a maximum range of approximately 6.9 km (4.3 mi), though effective direct fire range was limited to about 1-2 km, a muzzle velocity of around 884 m/s for AP projectiles, and a rate of fire up to 30 rounds per minute.^[3]^[1]^[8] A coaxial 7.62 mm (0.30 in) Browning M1919A4 machine gun provided secondary armament, with 2,500 rounds of ammunition carried aboard, primarily for anti-infantry suppression. The turret was traversed manually via a hand-operated mechanism, allowing a full 360° rotation, with a maximum traverse time of 15 seconds for a complete circle; elevation ranged from -10° to +30°. The gunner utilized an M46 or M46A2 telescope integrated into an M8 or M8A1 periscope for aiming, while the commander relied on a periscope sight for observation and target acquisition. These features prioritized simplicity and low weight over powered traversal systems, reflecting the tank's airborne design constraints.^[3]^[9] The Locust's armor was constructed from rolled homogeneous steel for the hull and cast homogeneous steel for the turret, welded together to form a lightweight protective envelope that sacrificed thickness for air-transportability. Maximum armor thickness reached 25.4 mm (1 in) on critical areas such as the turret front (sloped at 30°), gun shield (50° slope), driver's head cover, and lower hull front, while hull sides measured 9.5-12.7 mm (0.375-0.5 in) with slopes of 45° on upper sides. The turret sides and rear were also 25.4 mm, but the overall configuration left the vehicle highly vulnerable to anti-tank weapons, including German 37 mm Pak 36 guns, which could penetrate its armor at ranges beyond 200 yards. Thinner roof (9.5-19.1 mm) and floor (12.7 mm) plating offered minimal protection against top-attack or indirect fire.^[3]^[1]

Component	Thickness	Slope
Hull Upper Front	12.7 mm	65°
Hull Lower Front	25.4 mm	0°
Hull Upper Sides	9.5 mm	45°
Hull Lower Sides	12.7 mm	0°
Hull Rear	12.7 mm	9°
Hull Top/Floor	9.5-12.7 mm	90°
Turret Front	25.4 mm	30°
Turret Gun Shield	25.4 mm	50°
Turret Sides/Rear	25.4 mm	5°/0°
Turret Top	9.5-19.1 mm	90°

In British service, some M22 variants were fitted with two smoke grenade launchers on the turret sides to provide a defensive screening capability during retreats or maneuvers, though the vehicle lacked any nuclear, biological, or chemical (NBC) protection, underscoring the design trade-offs that limited armor and ancillary systems to maintain a combat weight under 7.5 tons.^[1]^[3]

Operational history

World War II service

In April 1944, the United States transferred approximately 260 M22 Locust light tanks to British forces under the Lend-Lease program, with these vehicles assigned to the 6th Airborne Armoured Reconnaissance Regiment of the 6th Airborne Division.^[1] The tanks underwent extensive training exercises in the United Kingdom, where crews practiced glider towing and deployment procedures using Hamilcar gliders, but logistical challenges, including the tanks' weight and the limitations of available aircraft, prevented their airdrop during earlier operations.^[1] Following the D-Day landings in Normandy, a small number of Locusts saw limited ground use for reconnaissance and support roles after being shipped across the Channel, though they were not employed in airborne assaults due to ongoing transport issues and the rapid advance of Allied forces.^[4] The M22 Locust's sole combat deployment occurred during Operation Varsity on March 24, 1945, when eight tanks were airdropped across the Rhine River near Hamminkeln, Germany, to support the British 6th Airborne Division's assault as part of the broader Allied crossing into the Ruhr.^[4] Transported in Hamilcar gliders, the Locusts faced immediate setbacks: one vehicle fell through the floor of its Hamilcar glider en route across the Rhine, killing the crew, while others suffered mechanical failures during landing, including engine damage and structural issues that rendered several inoperable.^[10] Of the surviving vehicles, only four were fully operational upon touchdown, with the others damaged by rough terrain or glider mishaps.^[1] In action, the operational Locusts provided valuable scouting and infantry support, suppressing German defensive positions with their 37 mm guns and aiding paratroopers in securing objectives amid heavy enemy resistance.^[4] They contributed to the advance toward the Issel River, where they helped capture key high ground north of Bergen and inflicted casualties on German forces, though their light armor proved vulnerable—one was knocked out by fire from a German self-propelled gun, and others drew intense artillery fire due to their visibility.^[1] By late March, the remaining tanks were withdrawn from frontline service and replaced by more capable Cromwell tanks, as the Locust's design limitations, including poor reliability and inadequacy against late-war German armor, rendered it obsolete.^[4] The regiment decommissioned the Locusts entirely by April 1945.^[10]

Postwar service

Following World War II, the U.S. Army inactivated the dedicated M22 Locust units, such as the 151st Airborne Tank Company on 31 December 1944 and the 28th Airborne Tank Battalion, due to the lack of suitable delivery systems and the need to reallocate personnel to other priorities.^[1] Approximately 25 M22s were deployed to Europe with the 6th Army Group in April 1944 but were not returned postwar, with most surplus vehicles ultimately scrapped or placed in storage.^[1] The tank was officially declared obsolete by the U.S. and British forces in January 1946, marking the end of its frontline potential amid the rapid evolution of armored warfare doctrine.^[5] In Britain, the approximately 260 M22 Locusts received via Lend-Lease were largely disposed of after 1945, with many sold as scrap or transferred abroad, though a few served as training hulks before final decommissioning.^[1] The British Army did not deploy the type in active service postwar, viewing it as unsuitable for emerging threats due to its light armor and armament limitations exposed during wartime trials.^[5] Several nations acquired surplus M22s for limited postwar roles, highlighting the tank's brief extension beyond Allied service. Egypt obtained about 26 demilitarized units in 1948 through intermediaries, employing them for armored reconnaissance in the 1948 Arab-Israeli War, where at least nine were captured by Israeli forces, underscoring the vehicle's obsolescence against more modern opposition.^[1] The Belgian Army received a number of M22s from British stocks around 1946, utilizing them as command vehicles alongside M4 Sherman regiments until the early 1950s.^[5] In the Netherlands, two M22s were employed for driver training from 1946 to 1951 before disposal, representing minor evaluation efforts amid the shift toward heavier airborne platforms like the later M551 Sheridan.^[1] By the mid-1950s, the M22's lightweight design rendered it entirely obsolete in favor of more capable successors.^[5]

Operators and legacy

Military operators

The United States developed and produced the M22 Locust airborne light tank, with a total of 830 units manufactured between April 1943 and February 1944 by Marmon-Herrington. Of these, approximately 570 were retained for domestic use, primarily for training purposes with U.S. airborne divisions such as the 151st Airborne Tank Company and the 28th Airborne Tank Battalion; the vehicle saw no combat deployment by American forces due to logistical challenges with glider transport.^[1]^[5]^[2] The United Kingdom was the primary combat operator of the M22 Locust, receiving 260 units through the Lend-Lease program starting in 1944. These were assigned to the 6th Airborne Armoured Reconnaissance Regiment of the British 6th Airborne Division, where they served in reconnaissance roles during Operation Varsity, the Allied crossing of the Rhine on March 24, 1945—the only combat action involving the tank.^[1]^[11]^[2] Postwar, Egypt acquired surplus M22 Locusts from Britain, with approximately 26 vehicles demilitarized units being remilitarized for service in the Royal Egyptian Army during the 1948 Arab-Israeli War, where they performed reconnaissance duties; at least nine were captured by Israeli forces.^[1] Belgium received a small number of M22 Locusts in 1946 from British surplus for use as command vehicles with M4 Sherman tank regiments and for training new tank crews, though many were later abandoned in the Belgian Congo.^[1] The Netherlands obtained two M22 Locusts postwar from Canadian surplus in 1946, employing them briefly for driver training before they were not adopted for further service.^[1]

Surviving vehicles

Several M22 Locust light tanks survive today, primarily in museums and private collections across Europe, the United States, and elsewhere, with estimates ranging from 16 to 22 complete or partial examples as of late 2025.^[12]^[1] Many of these vehicles are in restored or display condition, though some feature reproduction turrets or partial components due to wartime losses or postwar modifications. Preservation efforts focus on maintaining historical integrity while enabling public education and occasional demonstrations. At The Tank Museum in Bovington, UK, a fully restored M22 Locust (marked T158979) is on public display and operational, having been used in demonstrations as recently as August 2025.^[11]^[12] This example, restored in the early 2000s, represents one of the most complete and accessible survivors, highlighting the tank's airborne design features.^[11] In the United States, the American Heritage Museum in Hudson, Massachusetts, exhibits a restored M22 Locust acquired from the Littlefield Collection, in running condition for special events.^[12] The U.S. Army Armor & Cavalry Collection at Fort Benning, Georgia, holds at least one example (previously displayed), with conservation work documented in 2022; an adjacent partial vehicle at the National Infantry Museum features a replica turret and is stored indoors.^[12] Another restored hull, known as "Jumpin' Judy," is preserved at the U.S. Army Ordnance Museum at Fort Lee, Virginia, though not currently visible to the public.^[12] European collections include a running, restored M22 Locust at Heintz Barracks in Bastogne, Belgium, maintained by the Belgian armed forces for commemorative purposes since at least 2021.^[12] The Dutch Cavalry Museum in Delft, Netherlands, stores one example not on public display.^[12] In France, the MM Park in La Wantzenau holds a partial hull with a reproduction turret and original engine, sourced from the U.S. in the 2010s.^[12] Private collections account for several additional survivors, including a running example (serial number 110) at Roberts Armory in Rochelle, Illinois, featuring a reproduction turret and originally used as postwar farm equipment.^[12] Another in Georgetown, Texas, is undergoing restoration with a modern Chevrolet engine installed.^[12] The National Museum of Military Vehicles in Dubois, Wyoming, added a restored M22 Locust to its display in September 2025, transferred from a New York collection.^[12] Other notable examples include a restored display vehicle at Yad Mordechai Battlefield in Negba, Israel, commemorating 1948 conflicts, and a modified running example at the Royal Jordanian Tank Museum with a non-original engine and fabricated turret.^[12] In India, the Armoured Corps Museum in Ahmednagar holds one in unknown condition as of January 2025.^[12] No major new discoveries have been reported in 2025 inventories, though ongoing debates persist regarding potential wrecks in Egypt from postwar service, with no confirmed recoveries.^[12]