United States' M24 light tank, Chaffee

Photos

M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee: U.S. Ordnance Dept.	M24 Light Tank, Chaffee: U.S. Ordnance Dept.	M24 Light Tank, Chaffee: U.S. Ordnance Dept.
M24 Light Tank, Chaffee: US Army	M24 Light Tank, Chaffee: Imperial War Museum	M24 Light Tank, Chaffee at the Patton Museum in Ft Knox, Kentucky Chris Bobo	M24 Light Tank, Chaffee:
M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee: Mark Holloway
M24 Light Tank, Chaffee: Mark Holloway	M24 Light Tank, Chaffee's radio and a M3 sub machine gun "Grease Gun": Mark Holloway	M24 Light Tank, Chaffee's coaxial machine gun: Mark Holloway
1/72 Armor
Hobby Master
3601:	3602:

Design

After seeing how the M5 Light Tanks did with British forces in the Western Desert the US Ordnance Department and Cadillac, in April 1943, begin work on a new light tank with a 75 mm gun.^8,9,10

The M24 was named after US Army tank pioneer General Adna R. Chaffee.⁶

The armor was welded. The track was center guided and the tank used a torsion bar suspension. The engines were mounted on rail for easy maintenance. Each engine was identical and were interchangeable. The engines were the same engines as used in Cadillac automobiles.⁶ There was a bulkhead between the fighting compartment and the engine.⁶

There was a Cletrac controlled differential installed in the front of the hull for steering and braking.⁶ A synchronizer was incorporated in the transfer unit and the M24 was capable of 8 speeds forward and 4 reverse.⁵ In reverse the M24 could get up to 18 mph.⁵

Armament

The M24 used the same 75 mm gun that was originally designed for mounting in the B-25 Mitchell bomber for anti-ship use.^4,8 It had a concentric recoil system which saved turret space.¹ The firing trigger for the 75 mm was on the elevation hand wheel and for the machine gun on the power traverse control.⁹

There was recoil guard for the gunner and loader.⁹

For travel there was a lock that fastened to a bracket in the turret roof.⁹

The gun and a .30 cal machine gun were mounted in a Combination Gun Mount, M64.^5,9 Ammo was stored in water protected containers in the floor.^5,9

The hull machine gun had a bag that captured the expended casings.⁹ The gun was fed by a supply box on the left of the radio operator.⁹ There was a spring that helped counter balance the machine gun.⁹

The AA machine gun could be fire manually or electronically.⁶ The antiaircraft gun was mounted on a pintle at the rear of the turret.⁹

The 75 mm used a hydraulically operated stabilizer.^6,9 It could fire a 14.4 lb shell at a muzzle velocity of 2,050'/sec.^7,9

The 2" mortar was located on the right front side of the turret.⁹

Crew

In the front hull the driver sat on the left and the assistant driver / radio operator on the right with each having driving controls.^6,9 In the turret the gunner and loader were on the right and the commander on the left.^6,9 Originally it was intended to have only a four man crew with the assistant driver moving to the turret to load the gun.^6,9 The M24 had no turret basket, as the seats for the crew were suspended from the base ring.^5,6,9

The gunner used a combination telescope-periscope sight for sighting the main armament.⁹

The hatches for the driver and assistant driver could be opened regardless of the turret position.^1,9 There was an escape hatch placed in the floor of the hull.⁵

Prototype

Two pilot models (T24) were delivered in October 1943 by the Cadillac Motor Division.⁹

Production

The Ordnance Department immediately ordered 1,000 before service tests had begun and then raised to 5,000 vehicles.^1,8,9

Was Standardized in May 1944⁸ / July 1944.^1,5 First delivered in late 1944.

• Prototype: 2⁹
  • Manufacturer: Cadillac Motor Car Division⁵
• M24: 4,070^6,9, 4,371¹
  • Manufacturer: American Car & Foundry⁹, Cadillac Motor Car Division (GMC)⁷, Cadillac (Detroit)^6,9, Massey-Harris (Milwaukee)^6,7
    • Cadillac: 3,300⁹
    • Massey-Harris: 770⁹
  • Production: March 1944 - June 1945
• M19: 185^8,9
• M37: 316⁹
  • Manufacturer: Cadillac⁹
• M41: 60^6,9

Variants

• T24E1: Prototype that had a Continental engine and torque converter transmission.¹
• M24: Main production model.
• M19 Gun Motor Carriage: Had twin 40 mm M2 AA mounted at hull rear and the engines were moved forward to the center of hull.
• M37 Howitzer Motor Carriage: Was intended to replace M7 Priest. Had 105 mm howitzer.⁸ 448 ordered but only 316 delivered by war end. Carried 90 rounds and a crew of 7.
• M41 Howitzer Motor Carriage, "Gorilla"⁸: Engine moved to center of hull and 155 mm howitzer mounted at rear.⁸ 250 were ordered but only 60⁶ were completed when war ended and probably did not see action. Had crew of 12 with 8 of them riding in an ammunition carrier.
• T6E1: Tank recovery vehicle.
• T9 and T13: Utility vehicles. T9: Had bulldozer kit installed.
• T22E1, T23E1, and T33: Cargo carriers.
• T38 Mortar Motor Carriage: Carried 4.2" mortar.^8,9 It was cancelled.⁸
• T42 Cargo Tractor: Based on T33. Had torque transmission of the Hellcat.
• T43 Cargo Tractor: Lighter version of T42.
• T77E1 Multiple Gun Motor Carriage: Had 6 0.5" machine guns mounted in a new designed turret.⁸ Was cancelled.⁸
• T78: Was to mount a 90 mm antiaircraft gun.⁴
• T81: Mounted a Bofors 40 mm antiaircraft gun with two .50 cal machine guns.⁴
• T96: Was to mount a 155 mortar.⁴ Project cancelled at wars end.⁴

Usage

First delivered to Western Europe in November 1944.¹ First saw action in Italy.

A small number was supplied to Britain in 1945 and were named Chaffee.¹

Rhine River

Some M24s were used in crossing the Rhine in late 1944.⁹

After World War II

The M24s such much service during the Korean War and were used by French forces in Indo-China.^9,10

Specifications

	T24	M24 light tank, Chaffee
Crew	59	Commander, gunner, loader, driver, co-driver/radio operator2,9 45,7, 4 or 51,6, 52,3,4,8,9,10
Radio		SCR-5085,9
OR		SCR-5285,9
OR		SCR-5385
OR		British No. 195
Radio - command tank		SCR-5065
Physical Characteristics
Weight	38,750 lb9	38,750 lb5, 40,414 lb10, 40,500 lb2,3,8,9 18,370 kg8,10, 18,371 kg1 18 tons1, 18.37 tons4, 20.3 tons7
Weight - empty		36,250 lb9
Length w/gun	18'9	18'1,2,3,4,5,8,9,10 5.486 m8, 5.49 m1,4,10
Length w/o gun	16' 3"9	16' 3"5, 16' 4.5"2,4,8,9, 16.5'7 4.99 m4, 4.991 m8
Height	8' 1"9	8' 1"1,3,5, 8' 1.5"2,4,8,9,10, 9.1'7 2.46 m1, 2.4765 m8, 2.48 m4,10
Width	9' 4"9	9' 4"3,5, 9.5'7, 9' 8"1,2,4,8,9,10 2.946 m8, 2.95 m1,4,10
Width over tracks
Ground clearance	1' 5"9	1' 5"5, 1' 6"7
Ground contact length		9' 4"5, 10'7
Ground pressure	10.7 psi9	10.5 psi7, 10.7 psi5, 11 psi9
Turret ring diameter		60"5
Armament
Main	75 mm9	75 mm3,4,6,10 75 mm M61,2,5,8,9 75 mm M6, L/407
Secondary
MG		3: MG3 2: .30 cal MG8 2: 7.62 mm MG10 1: .50 cal MG8
MG - coaxial		1: .30 cal MG1,4,6 1: .30 cal Browning M1919A42,5,7,9
MG - hull		1: .30 cal MG1,4,6 1: .30 cal Browning M1919A42,5,7,9
MG - antiaircraft		1: .50 cal MG2,6 1: .50 cal Browning M2 HB5 1: .50 cal M2 MG7 1: .50 cal Browning M29 1: 12.7 mm (.50 cal) MG1,4 1: 12.7 mm MG10
Side arms		2" M3 Mortar, in turret5,9 1: 51 mm smoke mortar10 1: M2 .30 cal Tripod mount5 4: M3 .45 cal submachine guns5 1: M1 .30 cal Carbine with grenade launcher5 Grenades
Quantity
Main	489	481,2,5,7,8,9 (AP, APC, HE, WP, Canister, Smoke)
Secondary
MG		.30: 3,7502,5,7, 4,1258,9 .50: 4208,9, 4405,7
Side arms		Mortar: 145 .45: 720 Grenades: 8 (2: smoke, 6: fragmentation)5
Armor Thickness (mm)		92, 252, 12 - 384,10, 1" - 2.5"3 Front: 1"7,8 Front: 25.48 Hull: 2.5"6
Hull Front, Upper		1"5, 1"@60°9
Hull Front, Lower		1"5, 1"@45°9
Hull Sides, Upper		0.75"8, 0.75" - 1"5, 1"7, 1"@12°9 198
Hull Sides, Lower		0.75" - 1"5, 0.75"@12°9
Hull Rear		0.75"8, 0.75" - 1.25"5, 0.75"@0°9 198
Hull Top		0.5"5,9
Hull Bottom		0.375" - 0.5"5, 0.375"9
Turret Front		1"5,7, 1.25"6, 1.5"8 388 Gunshield: 1.5"5,9
Turret Sides		1"5,7, 1"@25°9
Turret Rear		1"5
Turret Top		0.5"5,9
Engine (Make / Model)		2 x Cadillac Twin 44T241,2,4,6,9,10, 2 x Cadillac Series 425, Twin Cadillac3, 2xCadillac7
Bore / stroke
Cooling		Liquid5, Water7,9
Cylinders		V-84,10, 2xV-85,7,9
Capacity
Net HP	2: 1109	110 each3,4,10, 110@3,400 rpm9, 110@3,600 rpm7, 2208, 220@3,4005
Power to weight ratio		10.86 HP/ton9
Compression ratio
Transmission (Type)		Hydra-Matic, 8 forward, 4 reverse5 Planetary, 4 forward, no reverse and Cadillac helical transfer case with 2 forward, and 2 reverse7 General Motors Hydramatic 4F, 2 forward, 1 reverse9
Gear ratio - 1st speed		9.19:15
- 2nd speed		5.96:15
- 3rd speed		3.62:15
- 4th speed		2.34:15
- 5th speed		4.05:15
- 6th speed		2.62:15
- 7th speed		1.59:15
- 8th speed		1.03:15
Reverse gear ratio - 1st speed		9.57:15
- 2nd speed		6.17:15
- 3rd speed		3.78:15
- 4th speed		2.44:15
Steering		Controlled differential7
Steering ratio
Starter		Electric7
Electrical system	24 volt9	24-volts5,7
Ignition		Distributor7
Fuel (Type)		Gasoline7,9,10
Octane		805
Quantity	110 gallons9	110 gallons5,7,9
Road consumption		0.9 mpg7
Cross country consumption		7 - 8 mpg9
Performance
Traverse		360°2,5, powered5 Hydraulic and manual7
Speed - Road	30 - 36 mph9	34 mph1,7, 35 mph2,3,4,5,8,10 55 kph1, 56 kph4,8,10
Speed - Cross Country		20-30 mph7, 25 mph2,3,8 40 kph8
Range - Road	100 miles9	100 miles2,4,7,8,9,10, 175 miles1,5 161 km4,8,10, 281 km1
Range - Cross Country		100 miles5
Turning radius	23'9	40'5
Elevation limits		-10° to +15°2,5
Fording depth	3' 6"9	3' 4"2,4,5,7,10 1.02 m4,10 3' 4" unprepared9 6' 6" prepared9
Trench crossing	7' 4"9	6' 6"5, 8'2,4,9,10, 8.25'7 2.44 m4,10
Vertical obstacle	2' 8"9	3'2,4,5,7,9,10 0.91 m4,10
Climbing ability	31°9	31° (60%) slope7,9, 60%5
Suspension (Type)		Torsion bar2,5,6,7,9
Wheels each side		55,7,9
Wheel size		25.5" x 4.5"5,9
Wheel size - idler		22.5" x 4.5"5
Return rollers each side		37
Tracks (Type)		Steel-rubber bushed, single pin5,7, T.729
Length
Width	1' 4"9	1' 4"2,5,7,8,9 0.406 m8
Diameter
Number of links	759	755,7,9
Pitch		5.5"5,7,9
Tire tread		Rubber7,9
Track centers/tread		8'2,5,7,8, 10'9 2.438 m8