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United States' M22 light tank⁸, Locust

T9E1 Light Tank prototype: US Ordnance Dept.	M22 Light Tank:	M22 Light Tank mounted under plane wing. US Ordnance Dept.	M22 Light Tank's top view of the hatches and combination gun mount. US Ordnance Dept.
M22 Light Tank. Looking inside turret basket with turret removed. US Ordnance Dept.	M22 Light Tank: US Ordnance Dept.	M22 Light Tank:	M22 Light Tank with Littlejohn adapter
M22's Tracks and Tools: US Ordnance Dept.	T92 Howitzer Motor Carriage, T28 heavy tank, and M22 Locust light tank: Life Magazine. (Mark Holloway)	M22 Locust light tank, T28 heavy tank: Life Magazine. (Mark Holloway)

Design

Based on the development of airborne forces by the Germans and Russians, the US Army decided in February 1941 that it should have airborne forces with armor support. General Motors, Christie, and Marmon-Herrington were asked to submit designs in May 1941.¹ Marmon-Herrington Corp. was selected and worked with the U.S. Army Ordnance Department Tank Engineering Division.

It was built with a welded hull and cast turret. The engine was located on the right side in the rear of the hull. The power train was located in the front and consisted of a fixed-ratio transfer case, a 4-speed transmission, and controlled differential.

To save on weight there was no power traverse or a gyrostabilizer.⁸

Transporting

The turret could be moved and four brackets were mounted above the suspension on the hull to allow for the tank to be attached to a C-54 Skymaster cargo airplane.⁷

The British could carry the M22 in their Hamilcar glider.⁷

Crew Compartment

The driver's hatch could be fastened open for driving in non-combat areas.⁸ A detachable windshield with cover was also provided. Two hatches in the roof of the turret and and escape hatch in the hull provided exit points.

Main Armament

The gun was mounted in a Combination Gun Mount, M53.

The 37 mm gun can fire a 1.9 lb AP shell with a muzzle velocity of 2,600'/sec.⁶

Suspension

There were two bogie assemblies that contained two wheels each side that used volute springs with two support rollers.⁵ The idler trailed on the ground in the rear.⁸

Prototype

The first prototype, the T9, was delivered in late 1941 and designated the Light Tank T9 (Airborne).

In January 1942, 2 pilot models designated T9E1 were ordered. The shape of the turret was altered, the power traverse, gyrostabilizers and bow MGs were not installed to save weight. These were tested by the 28th Airborne Tank Battalion.

Production

500 were ordered in April 1942 before service tests had begun. Eventually 1,900 were ordered but due to design changes and manufacturing problems only 830 were delivered.⁵

Standardized as the M22 in early 1943.⁷

The Ordnance Committee redesignated it Limited Standard in September 1944.⁸

• T9: 1
• T9E2: 2⁷
• M22: 830^1,5
  • Production: April 1942 - March 1945¹, April 1943 - February 1944⁵, - February 1944⁷
  • Manufacturer: Marmon-Herrington^5,6

Variants

• T9: Prototype.⁷ Had 37 mm main gun.⁷
• T9E1: Prototype.⁷ Hull shape changed.⁷ Powered traverse for the turret and the gyrostabilizer for the main armament was removed to save weight.⁷
• M22: Production model.

Usage

Never used in combat by US forces.⁵ No suitable glider or aircraft to transport it. Some were supplied to Egypt after the war.¹

British Use:

Some had a Littlejohn adaptor installed which increased the barrel length.¹

British used them in the Normandy landings.⁶

The British named it Locust and used it in the 6th Airborne Division in the Rhine crossing on March 22, 1945.^1,7 Were carried in the Hamilcar glider. Used with the Tetrarch during the crossing on March 24, 1945.⁵

	M22 light tank8
Crew	Commander, gunner, driver.2 31,2,3,5,6,7,8
Radio	SCR-5108
Physical Characteristics
Weight	16,000 lb8, 16,400 lb2,3,7, 17,024 lb 7.3 tons1, 7.4 tons5, 8.5 tons6 7,439 kg1 , 7,445 kg7
Length w/gun	12.9'6, 12' 11"1,2,3,5,7,8 3.937 m7, 3.94 m1
Length w/o gun
Height	5' 4"5, 5' 8"1, 5' 8.5"3,8, 6' 1"2,7, 6.1'6 1.74 m1, 1.854 m7
Width	7' 1"2,7, 7' 3.75"3,8, 7' 4"1,5, 7.5'6 2.159 m7, 2.23 m1
Width over tracks
Ground clearance	9.5"6, 10"8
Ground contact length	8' 8"8, 109"6
Ground pressure	6.7 psi6, 7.03 psi8, 7.2 psi
Turret ring diameter	47.5"8
Armament
Main	37 mm M61,2,8 37 mm3,5,7 37 mm M6, L/536
Secondary
MG	1: MG3 1: 7.62 mm (.30 cal) MG1 1: .30 cal Browning MG2 1: .30" Browning MG5 1: .30 cal MG7
MG - coaxial	1: .30 cal Browning M1919A4 MG6,8
Side arms	Tripod M2 .30 cal MG8 3: .45 cal M3 submachine guns8 Grenades
Quantity
Main	501,2,6,7,8 APC M51B1 or M51B28, AP M748, HE M638, Canister M28
Secondary
MG	2,5001,2,6,7,8
Side arms	.45 cal: 4508 Grenades: 128 (4: Fragmentation Mk II, 4: Smoke M8, 2: Thermite, 2: Offensive Mk III)8
Armor Thickness	0.75" - 1"3 Front: 0.98"7, 1"6 Side: 0.4"6
Hull Front, Upper	1"8
Hull Front, Lower	1"8
Hull Sides, Upper	0.75"8
Hull Sides, Lower	0.5"8
Hull Rear	0.5"8
Hull Top	3/8"8
Hull Bottom	0.5"8
Turret Front	0.6"6, 1"8 Mantlet: 0.6"6
Turret Sides	1"6,8
Turret Rear	0.75" 8
Turret Top	0.75"8
Engine (Make / Model)	Lycoming 0-435T1,2 Lycoming3,5, Lycoming O-435-T8
Bore / stroke
Cooling	Air3,5,6,8
Cylinders	63,8, 6 horizontally opposed6
Capacity
Net HP	1623,5,6,7, 162@2,800 rpm8
Power to weight ratio
Compression ratio
Transmission (Type)	4 forward, 1 reverse6
Gear ratios - 1st speed	1.857:18
- 2nd speed	1:18
- 3rd speed	0.463:18
- 4th speed	0.304:18
- reverse	1.666:18
Steering	Controlled differntial6
Steering ratio
Starter	Electric6
Electrical system	12 volt8
Ignition
Fuel (Type)
Octane	808
Quantity	55 gallons8, 57 gallons6
Road consumption	2.5 mpg6
Cross country consumption
Performance
Traverse	360°2,8, hand6
Max speed	35 mph8, 40 mph1,2,6,7 64 kph1,7
Cross country speed	27 mph, 30 mph2,7, 35 mph3 48 kph7
Road radius	110 miles8, 135 miles1,2,6,7 217 km7
Cross country radius
Turning radius	20'8
Elevation limits	-10° to +30°2,8
Fording depth	3'8, 3' 2"2, 3' 6"6
Trench crossing	5' 5"2,8
Vertical obstacle	12.4"6, 1' 0.5"2, 1' 4"8
Climbing ability	32° (63%) slope6, 50%8
Suspension (Type)	Two bogie assemblies that contained two wheels each side that used volute springs with two support rollers5 Vertical volute springs6,8
Wheel size	15" x 6"8
Wheels each side	46
Return rollers each side	26
Tracks (Type)	Dry pin6, Steel T788
Length
Width	11.25"2,7,8, 11.5"6 0.286 m7
Diameter
Number of links	1066,8
Pitch	3"8, 3.1"6
Tire tread
Track centers/tread	5.4'6, 5.9'6, 5' 10.5"2,6,8 1.791 m7

Sources:

1. The Encyclopedia of Tanks and Armored Fighting Vehicles - The Comprehensive Guide to Over 900 Armored Fighting Vehicles From 1915 to the Present Day, General Editor: Christopher F. Foss, 2002
2. British and American Tanks of World War Two, The Complete Illustrated History of British, American, and Commonwealth Tanks 1933-1945, Peter Chamberlain and Chris Ellis, 1969
3. Tanks of the World, 1915-1945, Peter Chamberlain, Chris Ellis, 1972
4. -
5. Tanks of World War II, Duncan Crow, 1979
6. Tank Data, Aberdeen Proving Grounds Series, 1968?
7. Airfix Magazine Guide #26 American Tanks of World War 2, Terry Gander and Peter Chamberlain, 1977
8. The American Arsenal, 1996

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