M24 Light Tank, Chaffee
Patton Museum in Ft Knox, Kentucky
Chris Bobo
US Army
Imperial War Museum
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. Two pilot models (T24) were delivered in October 1943 by the Cadillac Motor Division.
The Ordnance Department immediately ordered 1,000 before service tests had begun and then raised to 5,000 vehicles.1
Was named after US Army tank pioneer General Adna R. Chaffee.6
Was Standardized in July 1944.1 First delivered in late 1944. American Car & Foundry and Massey-Harris also produced the M24.
No turret basket, as the seats for the crew were suspended from the base ring.6 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.
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 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. It was capable of 8 speeds forward and 4 reverse. In reverse it could get up to 18 mph.
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.
Used the same 75 mm gun that was originally designed for mounting in the B-25 Mitchell bomber for anti-ship use. 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. Ammo was stored in water protected containers in the floor.
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
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
T24E1:
Prototype that had a Continental engine and torque converter transmission.1
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.
M41 Howitzer Motor Carriage, "Gorilla":
Engine moved to center of hull and 155 mm howitzer mounted at rear. 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.
M37 Howitzer Motor Carriage:
Was intended to replace M7 Priest. 448 ordered but only 316 delivered by war end. Carried 90 rounds and a crew of 7.
T77 Multiple Gun Motor Carriage:
Had 6 0.5" MGs mounted in a new designed turret.
T9 and T13:
Utility vehicles.
T22E1, T23E1, and T33:
Cargo carriers.
T42 Cargo Tractor:
Based on T33. Had torque transmission of the Hellcat.
T43 Cargo Tractor:
Lighter version of T42.
T9:
Had bulldozer kit installed.
T6E1:
Tank recovery vehicle.
| M24 | |
|---|---|
| Crew | Commander, gunner, loader, driver, co-driver/radio operator.2 47, 4 or 51,6, 52,3,4 |
| Physical Characteristics | |
| Weight | 38,750 lb, 40,500 lb2,3 18,371 kg1 18 tons1, 18.37 tons4, 18.4 tons5, 20.3 tons7 |
| Length w/gun | 18'1,2,3,4 5.49 m1,4,5 |
| Length w/o gun | 16' 3", 16' 4.5"2,4, 16.5'7 4.99 m4 |
| Height | 8' 1"1,3, 8' 1.5"2,4, 9.1'7 2.46 m1, 2.48 m4, 2.95 m5 |
| Width | 9' 4"3, 9.5'7, 9' 8"1,2,4 2.95 m1,4,5 |
| Width over tracks | |
| Ground clearance | 1' 5", 18'7 |
| Ground contact length | 9' 4", 120"7 |
| Ground pressure | 10.5 psi7, 10.7 psi, 11.3 psi |
| Turret ring diameter | 60" |
| Armament | |
| Main | 75 mm3,4,6 75 mm M61,2,5 75 mm M6, L/407 |
| Secondary | |
| MG | 3: MG3 .30 cal Browning M1919A4, coaxial, hull .50 cal Browning M2-HB AA 2: 7.62 mm (.30 cal) MG1,4, coaxial4, 1: 12.7 mm (.50 cal) MG1,4, AA4 2: .30 cal Browning MG (one coaxial).2 2: .30 cal MG, coaxial, hull5,6 .50 cal MG, AA.2,5,6 2: .30 cal M1919A4 MG, hull, coaxial7 .50 cal M2 MG, AA7 |
| Side arms | 51 mm smoke mortar 2" Smoke mortar in roof5 M2 .30 cal Tripod mount 4: M3 .45 cal submachine guns Grenades |
| Quantity | |
| Main | 481,2,5,7 (AP, APC, HE, WP, Canister, Smoke) |
| Secondary | |
| MG | .30: 3,7502,7 .50: 4407 |
| Side arms | Mortar: 14 .45: 720 Grenades: 8 |
| Armor Thickness (mm) | (Actual thickness to horizontal) 92, 252 12 - 384, 1" - 2.5"3 Front: 1"7, 255 Side: 1"7, 255 Hull: 2.5"6 Turret: 1.25"6 |
| Hull Front, Upper | 1" (2.5") |
| Hull Front, Lower | 1" (1.5") |
| Hull Sides, Upper | (0.75-1") |
| Hull Sides, Lower | |
| Hull Rear | 0.75" (0.75-1.25") |
| Hull Top | 0.5"@90° |
| Hull Bottom | 3/8-0.5"@90° |
| Turret Front | 1"7 (1.25") Gunshield: 1.5" (2-2.25") |
| Turret Sides | 1"7 (1.25") |
| Turret Rear | 1" (1") |
| Turret Top | 0.5"@90° |
| Engine (Make / Model) | 2 x Cadillac Twin 44T241,2,4,6 2 x Cadillac Series 42 Twin Cadillac3 2xCadillac7 |
| Bore / stroke | |
| Cooling | Water7 |
| Cylinders | V-84, 2xV-87 |
| Capacity | |
| Net HP | 110 each3,4, 110@3.600 rpm7, 2205 |
| Power to weight ratio | |
| Compression ratio | |
| Transmission (Type) | Hydra-Matic, 8 forward, 4 reverse Planetary, 4 forward, no reverse and Cadillac helical transfer case with 2 forward, and 2 reverse7 |
| Steering | Controlled differential7 |
| Steering ratio | |
| Starter | Electric7 |
| Electrical system | 24-volts7 |
| Ignition | Distributor7 |
| Fuel (Type) | Gasoline7 |
| Octane | |
| Quantity | 110 gallons7 |
| Road consumption | 0.9 mpg7 |
| Cross country consumption | |
| Performance | |
| Traverse | 360°2, powered Hydraulic and manual7 |
| Max speed | 34 mph1,7, 35 mph2,3,4 55 kph1, 56 kph4, 58 kph5 |
| Cross country speed | 20-30 mph7, 25 mph2,3 |
| Road radius | 100 miles2,4,7, 175 miles1 161 km4, 281 km1 |
| Cross country radius | 100 miles |
| Turning radius | 40' |
| Elevation limits | -10° To +15°2 |
| Fording depth | 3' 4"2,4,7 1.02 m4 3' 4" unprepared 6' 6" prepared |
| Trench crossing | 6' 6", 8'2,4, 8.25'7 2.44 m4 |
| Vertical obstacle | 3'2,4,7 0.91 m4 |
| Climbing ability | 31° (60%) slope7 |
| Suspension (Type) | Torsion bar.2,6,7 |
| Wheels each side | 57 |
| Return rollers each side | 37 |
| Tracks (Type) | Steel-rubber bushed, single pin7 |
| Length | |
| Width | 1' 4"2,7 |
| Diameter | |
| Number of links | 757 |
| Pitch | 5.5"7 |
| Tire tread | Rubber7 |
| Track centers/tread | 8'2,7 |
| Production | Cadillac Motor Car Division, GMC, 3/44-6/45-: 4,3711, 4,415, 4,070 Cadillac (Detroit), Massey-Harris (Milwaukee): 4,0706 Cadillac Motor Car Division (GMC) and Massey Harris Co.7 |
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
- Jane's World War II Tanks and Fighting Vehicles The Complete Guide, Leland Ness, 2002
- Tanks of World War II, Duncan Crow, 1979
- Tank Data, Aberdeen Proving Grounds Series, 1968?
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