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United States' M24 light tank⁹, Chaffee

M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee:
M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee:	M24 Light Tank, Chaffee:	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:
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: Mark Holloway
M24 Light Tank, Chaffee: Mark Holloway	M24 Light Tank, Chaffee's coaxial machine gun: Mark Holloway	M24 Light Tank, Chaffee's radio and a M3 sub machine gun "Grease Gun": Mark Holloway

1/72 Armor
Hobby Master
3601:	3602:

Design

In April 1943 the US Ordnance Department and Cadillac begin work on a new light tank with a 75 mm gun to replace the M5 Light Tank.⁸

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.⁹ In reverse the M24 could get up to 18 mph.⁹

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.⁸ It had a concentric recoil system which saved turret space.¹ The gun and a .30 cal MG were mounted in a Combination Gun Mount, M64.⁹ Ammo was stored in water protected containers in the floor.⁹

The AA machine gun could be fire manually or electronically.⁶ The 75 mm used a hydraulically operated stabilizer.⁶ It could fire a 14.4 lb shell at a muzzle velocity of 2,050'/sec.⁷

The antiaircraft gun was mounted on a pintle at the rear of the turret. The 2" mortar was located on the right front side of the turret.

Crew

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

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

Prototype

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

Production

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

Was Standardized in May 1944⁸ / July 1944.^1,9 First delivered in late 1944.

Prototype: Cadillac Motor Car Division⁹
M24: 4,070⁶, 4,371¹, 4,415
- Manufacturer: American Car & Foundry, Cadillac Motor Car Division (GMC)⁷, Cadillac (Detroit)⁶, Massey-Harris (Milwaukee)^6,7, GMC
- Production: March 1944 - June 1945

Variants

T24E1: Prototype that had a Continental engine and torque converter transmission.¹
M24:
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. 904 ordered in August 1944, but only 285 were delivered.⁸
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 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" MGs mounted in a new designed turret.⁸ Was cancelled.⁸

Usage

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

It was used in the crossing of the Rhine.

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

	M24 light tank⁹, Chaffee
Crew	Commander, gunner, loader, driver, co-driver/radio operator.² 4^7,9, 4 or 5^1,6, 5^2,3,4,8
Radio	SCR-508⁹
OR	SCR-528⁹
OR	SCR-538⁹
OR	British No. 19⁹
Radio - command tank	SCR-506⁹
Physical Characteristics
Weight	38,750 lb⁹, 40,500 lb^2,3,8 18,370 kg⁸, 18,371 kg¹ 18 tons¹, 18.37 tons⁴, 20.3 tons⁷
Length w/gun	18'^1,2,3,4,8,9 5.486 m⁸, 5.49 m^1,4
Length w/o gun	16' 3"⁹, 16' 4.5"^2,4,8, 16.5'⁷ 4.99 m⁴, 4.991 m⁸
Height	8' 1"^1,3,9, 8' 1.5"^2,4,8, 9.1'⁷ 2.46 m¹, 2.4765 m⁸, 2.48 m⁴
Width	9' 4"^3,9, 9.5'⁷, 9' 8"^1,2,4,8 2.946 m⁸, 2.95 m^1,4
Width over tracks
Ground clearance	1' 5"⁹, 1' 6"⁷
Ground contact length	9' 4"⁹, 10'⁷
Ground pressure	10.5 psi⁷, 10.7 psi⁹, 11.3 psi
Turret ring diameter	60"⁹
Armament
Main	75 mm^3,4,6 75 mm M6^1,2,8,9 75 mm M6, L/40⁷
Secondary
MG	3: MG³ 2: .30 cal MG⁸ 1: .50 cal MG⁸
MG - coaxial	1: .30 cal MG^1,4,6 1: .30 cal Browning M1919A4^2,7,9
MG - hull	1: .30 cal MG^1,4,6 1: .30 cal Browning M1919A4^2,7,9
MG - antiaircraft	1: .50 cal MG^2,6 1: .50 cal Browning M2 HB⁹ 1: .50 cal M2 MG⁷ 1: 12.7 mm (.50 cal) MG^1,4
Side arms	2" M3 Mortar, in turret⁹ 1: M2 .30 cal Tripod mount⁹ 4: M3 .45 cal submachine guns⁹ 1: M1 .30 cal Carbine with grenade launcher⁹ Grenades
Quantity
Main	48^1,2,7,8,9 (AP, APC, HE, WP, Canister, Smoke)
Secondary
MG	.30: 3,750^2,7,9, 4,125⁸ .50: 420⁸, 440^7,9
Side arms	Mortar: 14⁹ .45: 720 Grenades: 8 (2: smoke, 6: fragmentation)⁹
Armor Thickness (mm)	9², 25² 12 - 38⁴, 1" - 2.5"³ Front: 1"^7,8 Front: 25.4⁸ Hull: 2.5"⁶
Hull Front, Upper	1"⁹
Hull Front, Lower	1"⁹
Hull Sides, Upper	0.75"⁸, 0.75" - 1"⁹, 1"⁷ 19⁸
Hull Sides, Lower	0.75" - 1"⁹
Hull Rear	0.75"⁸, 0.75" - 1.25"⁹ 19⁸
Hull Top	0.5"⁹
Hull Bottom	3/8" - 0.5"⁹
Turret Front	1"^7,9, 1.25"⁶, 1.5"⁸ 38⁸ Gunshield: 1.5"⁹
Turret Sides	1"^7,9
Turret Rear	1"⁹
Turret Top	0.5"⁹
Engine (Make / Model)	2 x Cadillac Twin 44T24^1,2,4,6, 2 x Cadillac Series 42⁹, Twin Cadillac³, 2xCadillac⁷
Bore / stroke
Cooling	Liquid⁹, Water⁷
Cylinders	V-8⁴, 2xV-8^7,9
Capacity
Net HP	110 each^3,4, 110@3.600 rpm⁷, 220⁸, 220@3,400⁹
Power to weight ratio
Compression ratio
Transmission (Type)	Hydra-Matic⁹, 8 forward, 4 reverse⁹ Planetary, 4 forward, no reverse and Cadillac helical transfer case with 2 forward, and 2 reverse⁷
Gear ratio - 1st speed	9.19:1⁹
- 2nd speed	5.96:1⁹
- 3rd speed	3.62:1⁹
- 4th speed	2.34:1⁹
- 5th speed	4.05:1⁹
- 6th speed	2.62:1⁹
- 7th speed	1.59:1⁹
- 8th speed	1.03:1⁹
Reverse gear ratio - 1st speed	9.57:1⁹
- 2nd speed	6.17:1⁹
- 3rd speed	3.78:1⁹
- 4th speed	2.44:1⁹
Steering	Controlled differential⁷
Steering ratio
Starter	Electric⁷
Electrical system	24-volts^7,9
Ignition	Distributor⁷
Fuel (Type)	Gasoline⁷
Octane	80⁹
Quantity	110 gallons^7,9
Road consumption	0.9 mpg⁷
Cross country consumption
Performance
Traverse	360°^2,9, powered⁹ Hydraulic and manual⁷
Max speed	34 mph^1,7, 35 mph^2,3,4,8,9 55 kph¹, 56 kph^4,8
Cross country speed	20-30 mph⁷, 25 mph^2,3,8 40 kph⁸
Road radius	100 miles^2,4,7,8, 175 miles^1,9 161 km^4,8, 281 km¹
Cross country radius	100 miles⁹
Turning radius	40'⁹
Elevation limits	-10° to +15°^2,9
Fording depth	3' 4"^2,4,7,9 1.02 m⁴ 3' 4" unprepared 6' 6" prepared
Trench crossing	6' 6"⁹, 8'^2,4, 8.25'⁷ 2.44 m⁴
Vertical obstacle	3'^2,4,7,9 0.91 m⁴
Climbing ability	31° (60%) slope⁷, 60%⁹
Suspension (Type)	Torsion bar^2,6,7,9
Wheels each side	5^7,9
Wheel size	25.5" x 4.5"⁹
Wheel size - idler	22.5" x 4.5"⁹
Return rollers each side	3⁷
Tracks (Type)	Steel-rubber bushed, single pin^7,9
Length
Width	1' 4"^2,7,8,9 0.406 m⁸
Diameter
Number of links	75^7,9
Pitch	5.5"^7,9
Tire tread	Rubber⁷
Track centers/tread	8'^2,7,8,9 2.438 m⁸

Sources:

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
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
Tanks of the World, 1915-1945, Peter Chamberlain, Chris Ellis, 1972
The Encyclopedia of Weapons of World War II, Chris Bishop, 1998
-
Tanks of World War II, Duncan Crow, 1979
Tank Data, Aberdeen Proving Grounds Series, 1968?
Airfix Magazine Guide #26 American Tanks of World War 2, Terry Gander and Peter Chamberlain, 1977
The American Arsenal, 1996