| M18: General | |||
| Date of first acceptance | July 1943 | Total acceptances | 2507 |
| Manufacturers | Buick Motor Car Division of General Motors Corp. | Crew |
|
| M18: Dimensions | |||
| Combat weight | 37,557lbs 17,036kg |
Height over AAMG | 101" 257cm |
| Length without gun | 208" 528cm |
Gun overhang forward | 54" 140cm |
| Width overall | 113" 287cm |
Tread | 94.625" 240.35cm |
| Ground clearance | 14.25" 36.20cm |
Fire height | 73.8" 187cm |
| Turret ring diameter | 69" 175cm |
Ground pressure, zero penetration | 11.9psi .835kg/cm² |
| M18: Armament | |||||
| Type | Mount | Ammunition | Traverse | Max traverse rate | Elevation |
| 76mm Gun M1A1, M1A1C, or M1A2 | M1 in turret | 45 rounds (9 ready) |
360° (manual and hydraulic) |
24°/sec | +20° to -10° (manual) |
| .50cal M2HB MG | Ring mount on turret | 800 rounds | 360° (manual) |
-- | Manual |
| M18: Armor | ||
| Assembly | ||
| Welding | ||
| Hull | ||
| Rolled homogeneous steel | ||
| Location | Thickness | Angle from vertical |
| Upper front | .5" 1.3cm |
64° |
| Upper middle front | .5" 1.3cm |
38° |
| Lower middle front | .5" 1.3cm |
24° |
| Lower front | .5" 1.3cm |
53° |
| Upper sides | .5" 1.3cm |
23° |
| Lower sides | .5" 1.3cm |
0° |
| Upper rear | .5" 1.3cm |
13° |
| Lower rear | .5" 1.3cm |
35° |
| Top | .31" .79cm |
90° |
| Floor | .19" .48cm |
90° |
| Turret | ||
| Rolled and cast homogeneous steel | ||
| Location | Thickness | Angle from vertical |
| Gun shield | .75" 1.9cm |
0° to 60° |
| Front (cast) | 1.0" 2.5cm |
23° |
| Sides | .5" 1.3cm |
20° |
| Rear | .5" 1.3cm |
9° |
| Top | Open | |
| M18: Automotive | |||||
| Engine | Continental R-975-C1 or -C4; 9 cylinder, 4 cycle, static radial, supercharged gasoline | ||||
| Horsepower | Net: 400@2400rpm Gross: 460@2400rpm |
Torque | Net: 940 ft-lb@1700rpm Gross: 1025 ft-lb@1800rpm |
Fuel capacity | 165gal 625L |
| Transmission | 900T Torqmatic, 3 speeds forward, 1 reverse | ||||
| Steering | Controlled differential, steering levers | ||||
| Brakes | Mechanical, external contracting | ||||
| M18: Suspension | ||
| Type | Road wheels | Track return rollers |
| Torsion bar | 5 individually sprung dual/track | 4 dual/track |
| Drive sprockets | Idlers | Shock absorbers | 31-tooth front drive | Dual adjustable at rear of track | On first 2 and last 2 road wheels/track |
| M18: Track | |||||||
| T69 | |||||||
| Center guide, single pin, rubber bushed, steel, parallel grouser | |||||||
| Width | 12" (14.375" including track pins) 30cm (36.513cm including track pins) |
Pitch | 5.09" 12.9cm |
Shoes/track | 83 | Ground contact length | 116.5" 295.9cm |
| M18: Performance | |||
| Max level road speed | 50mph 80kph |
Max trench | 73.2" 186cm |
| Max grade | 60% | Angle of approach | 28° |
| Angle of departure | 26.5° | Max vertical obstacle | 36" 91cm |
| Min turning diameter | 66' 20m |
Max fording depth | 48" 120cm |
| Cruising range | ~100mi, roads ~160km, roads |
||
The M18 tank destroyer, known unofficially as Hellcat, was armed with the same 76mm gun series as the 76mm-gun medium tanks M4. The M18 was very fast, and its torsion bar suspension ensured a smooth ride over rough terrain. The drivers were provided with split hatches in the hull roof, and the turret was open-topped except for a small plate welded to the front right of the turret, which also supported the 76mm ammunition ready rack. The hull front featured a large service hatch for access to the vehicle's transmission and differential.
The 76mm guns themselves differ in the following ways: the M1A1C had the end of the barrel threaded for a muzzle brake, and the rifling of the M1A2 was one turn in 32 calibers versus one turn in forty for the other weapons. All M1A2s were equipped with muzzle brakes.
