6-ton 6x6 truck

6-ton 6x6 Truck
Prime Mover Cargo Truck (White)
Type	6-ton (5,443kg) 6x6 truck
Place of origin	United States
Production history
Designer	Corbitt
Manufacturer	Brockway, Corbitt, FWD Ward LaFrance, White
Produced	1941–1945
Number built	219,882
Specifications (Prime mover[1])
Weight	22,900 lb (10,400 kg) (empty)
Length	24 feet 1 inch (7.34 m)
Width	8 feet (2.44 m)
Height	9 feet 6 inches (2.90 m)
Engine	Hercules HXD 202 hp (151 kW)
Transmission	4 speed X 2 range
Suspension	Live beam axles on leaf springs
Operational range	200 mi (321.9 km)
Speed	37 mph (60 km/h)

The 6-ton, 6×6 Truck (G512, 514, 547, 569) was a family of heavy tactical trucks built for the United States Armed Forces during World War II. The basic cargo version was designed to transport a 6-ton (12,000 lb (5,400 kg)) load over all terrain in all weather. The chassis was built by Brockway Motor Company, The Corbitt Company, The Four Wheel Drive Auto Company (FWD), Ward LaFrance Truck Corporation, and White Motor Company. They were replaced by the M39 series 5-ton (4536 kg) trucks in the 1950s.

History

In the late 1930s Corbitt, who had sold the US Army trucks since 1917, began developing a prime mover with a 6-ton (5,443 kg) off road load rating for the US Army. In 1941 the Model 50SD6 was standardized and went into production. Shortly after White began building, Brockway began in 1942, FWD in 1945. Ward LaFrance also built the chassis. All manufacturer’s models were virtually identical, with very minor variations.^[2][3]

Early models had closed cabs with full doors, in 1942 open cabs with half doors were introduced. Both could be equipped with a ring for a .50 cal. machine gun. Cranes had an open half-cab.^[4]

Specifications

Engine and driveline

Hercules HXD (right front view)

All models used Hercules HXD engines, a 855 cu in (14.0 L) L-head inline 6 cylinder gasoline engine developing 202 hp (151 kW) at 2100 rpm and 330 lbf·ft (447 N·m) of torque at 900 rpm.^[5]

A Fuller 4-speed manual non-synchronized transmission with a very low 1st and direct 4th gear was used. A Timken transfer case had a high and low range, a neutral for power take-off (PTO) operation, and engaged the front axle. The front axle could only be used on low-traction surfaces, on hard ground it could cause driveline damage. The low range could only be used when the front axle was engaged, to distribute the increased torque between all three axles. Axles were Timken double reduction “pumpkin” type. Tractors had heavier rear axles.^[6][7]

Chassis

Most models had a ladder frame with three live axles, the front on semi elliptical leaf springs, the rear tandem on quarter elliptical leaf springs with locating arms. The exception was the crane truck, which had a walking beam rear suspension for stability. ^[8]

There were three wheelbases. The short, used for prime movers, was 185 inches (4.70 m), the long, used for cranes, was 197 inches (5.00 m), and the extra long, used for bridge erectors, was 220 inches (5.59 m). (Measurements are from the centerline of the front axle to the centerline of rear bogie).^[9]

Prime movers and tankers had 10.00x22 size tires, while bridge, crane, and semi-tractor trucks had 14.00x20s with a larger cross-section. All had dual rear tires. Brakes were full air with drum brakes on all wheels. Prime movers had adjustable electrical brake connections for trailer brakes.^[10][11]

Prime movers had a 25,000 lb (11,000 kg) winch behind the cab, most other trucks had a front-mounted two-drum winch for self-recovery. Trucks converted from prime mover chassis had no winch at all.^[12]

Models

Prime Mover Cargo Truck

Bridge Erection Truck

Crane Trucks

Tractor Truck

Gasoline Tank Truck

Fire Crash Truck

Prime Mover Van Truck

Prime Mover Cargo Truck

Prime movers were used to tow field artillery pieces, they also transported gun crews, equipment, and ammunition. They had a pintle hitch at the rear for towing up to 40,000 lb (18,000 kg). Another pintle at the front could be used to emplace the piece. A mid-mounted 25,000 lb (11,000 kg) winch had a centered cable drum and a capstan on the right side. Pulleys and rollers routed the cable under the body and out the rear frame cross-member.

With a short wheelbase, mid-mounted winch, and short overhang, the body could only be 9 ft (2.74 m) feet long. Both sides had sideboards with fold down troop seats and bows for a tarpaulin. Two spare tires were mounted inside the body, one along each side. Early models had all metal bodies, in 1942 they were replaced by largely wood types to conserve steel. All Corbitts were prime movers, White also built them.^[13][14]

Bridge Erection Truck

Built on a long, reinforced chassis, they were used to carry treadway pontoon bridges for combat engineers. A large double arm hydraulic boom built by Heil was used to self unload components, often directly into a river. A 25,000 lb (11,000 kg) winch was mounted at the front. They had an auxiliary air compressor and large reservoir tanks, used to inflate pontoon floats. Brockway built 1,166, White 1,152, Ward LaFrance 589, and FWD 168.^{[15][16][17][18][19][20]}

Crane Truck

Quickway cranes were used by combat engineers to unload and assemble bridge components. The rotating crane was powered by an auxiliary IHC 334 cu in (5.5 L) inline 4 cylinder engine developing 35 hp (26 kW). As a derrick it could lift 13,000 lb (5,900 kg) at a minimum radius of 10 ft (3.05 m) and 5,550 lb (2,520 kg) at a maximum radius of 25 ft (7.62 m). A shovel, clamshell, dragline, and drilling equipment could also be used. The cab had a windshield on the left side only, in transit the boom went over the right side and was braced to the front bumper. Tire size was 14.00x20. A 25,000 lb (11,000 kg) winch was mounted on the front.^[10][21][22]

Tractor Truck

As artillery pieces were being towed more often by tracked vehicles, prime mover chassis became available for other uses. In 1945 White built 112 semi-tractors with a fifth wheel and heavier rated Timken axles. Tire size was 14.00x20. Maximum speed was 40 mph (64 km/h), the highest in the series. A 25,000 lb (11,000 kg) winch was mounted on the front.^[10][23][24]

Gasoline Tank Truck

Wanting a fuel tanker larger than the CCKW, the Army ordered 25 from White. The body had 4 self-sealing tank compartments for a total of 2,000 US gal (7,600 l). A bow and canvas top was fitted, so the truck could be disguised as a common cargo truck. Early trucks had a hard cab and a front mounted pintle hitch, later trucks had an open cab and a 25,000 lb (11,000 kg) front winch. A 2,000 US gal (7,600 l) gallon trailer could be towed. No follow up orders were made.^[25][26][27]

Fire Crash Truck

Fire Crash trucks were used by the Army Air Force to fight fires from airplane crashes. Brockway and Ward LaFrance chassis were equipped with bodies by Mack and American LaFrance (a separate company), both had auxiliary engines for the pump. This allowed the truck to move while two foam nozzles were being used. American LaFrance used their own 12 cylinder engine and 4 stage pump. Mack used a Continental R-6602 developing 225 hp (168 kW) to drive a Hale centrifugal pump capable of 325 US gal/min (1,230 l/min) at 500 psi (3,400,000 Pa).^{[28][29][30][31]}

Prime Mover Van Truck

White built communication vans for the Army Air Force on the prime mover wheelbase. Bodies were from Superior and Thomas. They were used to tow and power the SCR-545-A anti-aircraft radar set.^[25][32][33]

Dimensions

Model Manufacturer	Wheelbase	Length	Width	Height	Weight empty
Prime Mover Corbitt[9]	short	23 ft 9 in (7.24 m)	8 ft (2.44 m)	9 ft 10 in (3.00 m)	22,020 lb (9,990 kg)
Bridge Brockway[9]	extra long	30 ft 10 in (9.40 m)	8 ft 4 in (2.54 m)	9 ft (2.74 m)	26,500 lb (12,000 kg)
Crane Brockway[9]	long	34 ft 8 in (10.57 m)	8 ft 4 in (2.54 m)	11 ft 4 in (3.45 m)	35,275 lb (16,000 kg)
Tractor White[10]	short	23 ft 3 in (7.09 m)	8 ft 5 in (2.57 m)	9 ft 5 in (2.87 m)	22,070 lb (10,010 kg)
Tank White[10]	short	23 ft 10 in (7.26 m)	8 ft 2 in (2.49 m)	8 ft (2.44 m)	23,820 lb (10,800 kg)
Fire Crash Brockway[30]	long	29 ft 7 in (9.02 m)	8 ft 8 in (2.64 m)	12 ft 6 in (3.81 m)	31,200 lb (14,200 kg)
Van White[33]	short	24 ft (7.32 m)	8 ft (2.44 m)	10 ft 5 in (3.18 m)	21,200 lb (9,600 kg)

References

1. TM 9-813 (19 Feb 1944). "6-ton 6x6 Truck (White, Corbit, and Brockway)". US War Dept. pp. 17, 124–125. Retrieved 21 Feb 2016.
2. Crismon, Fred W (2001). US Military Wheeled Vehicles (3 ed.). Victory WWII Pub. pp. 363, 368–370. ISBN 0-970056-71-0.
3. Doyle, David (2003). Standard catalog of U.S. Military Vehicles. Kraus Publications. pp. 208–212. ISBN 0-87349-508-X.
4. TM 9-813 (1944), p. 6.
5. TM 9-813 (1944), pp. 124-125.
6. Doyle (2003).
7. TM 9-813 (1944), pp. 25-28.
8. TM 9-813 (1944), pp. 202, 215, 242-245.
9. TM 9-813 (1944), p. 17.
10. Doyle (2003), p. 212.
11. TM 9-813 (1944), pp. 224-226, 238.
12. TM 9-813 (1944), pp. 29-30.
13. Doyle (2003), pp. 208–209, 212.
14. Doyle, David (2015). Six-Ton Trucks. Ampersand. pp. 3, 6–46. ISBN 978-0-9895547-9-4.
15. Crismon (2001), pp. 368–369.
16. Doyle (2003), pp. 208–212.
17. Doyle (2015), pp. 4,53-87.
18. TM 9-813 (1944), pp. 302–303.
19. TM 5-8064 (6 May 1944). "Crane, Truck Bridge Erector". US War Dept. Retrieved 30 Aug 2015.
20. TM 5-272 (9 May 1944). "Steel Treadway Bridge M2". US War Dept. Retrieved 26 Jan 2016.
21. Crismon (2001), p. 431.
22. Doyle (2015), pp. 4, 88-109.
23. Crismon (2001), p. 370.
24. Doyle (2015), pp. 5, 120-128.
25. Crismon (2001), p. 369.
26. Doyle (2003), pp. 210, 212.
27. Doyle (2015), pp. 4-5, 110-115.
28. Doyle (2015), pp. 5, 116-119.
29. TM 9-2800 (27 Oct 1947). "Military Vehicles". US Dept. of the Army. p. 321. Retrieved 25 Jun 2015.
30. TM 9-2800 (1947), p. 321.
31. Vanderveen, Bart (1998). A record of military Macks in the Services and beyond. After the Battle. p. 78. ISBN 1-870067-09-6.
32. Doyle (2015), pp. 3-4, 47-52.
33. TM 9-2800 (1947), p. 304.