SUNNYVALE, Calif. -- The Army's newest high performance grounds vehicle has learned to swim in California water trials conducted by Lockheed Missiles & Space Co.
MS Twister moving over rubble pile on Lockheed test course.
LS & MS Twister fighting vehicle, XM808, comes down slope on Santa Cruz Mountain test course.
MS Twister swimmer dives into riverbank brush.
MS Twister swimmer emerges from brush and enters water.
MS Twister moving through water.
On-board camera looking ahead over driver.
CU Twister's front body moving through water. Vehicle moves past camera for CU of rear body.
MS Twister from shore. Vehicle moves to CU and climbs 60 per cent bank.
Initials M70-93P M70-93C
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Background: SUNNYVALE, Calif. -- The Army's newest high performance grounds vehicle has learned to swim in California water trials conducted by Lockheed Missiles & Space Co.
The aerospace firm announced today the completion of swimming tests in mountain lakes and the Sacramento River delta where the Army's Twister showed it could handle deep water as well as rugged terrain.
Propelled by a water jet developing 2,600 pounds of thrust, the fast charging Army machine churned across rivers and lakes at speeds in excess of six miles per hour--a speed considered quite respectable for Army vehicles.
Lockheed originated the two-bodied, eight-wheel Twister concept and built three vehicles for the Army under contract to Army Tank-Automotive Command. Two Twisters-- a tested like the swimmer, and the weapon-carrying XM 808-- are being tested by the Army at the Aberdeen Proving Ground in Maryland and at Fort Knox, Ky.
"The success of the swimmer means Twister has established a unique advantage in water-crossing operations, "said Steve Hodges, Lockheed's manager of Ground Vehicle Systems. "many of today's military vehicles can swim, but have trouble getting in and out of the water. Twister's two-bodied design makes this easier to do."
The two bodies of the Twister vehicles, each powered by its own engine, are linked by a pivoting yoke which enables them to pivot freely. In climbing out of the water, the rear body is pushed shoreward by the water jet, while the front body pitches up so that the four front wheels can grab the bank for traction.
During operations in Lexington Reservoir near Los Gatos, Calif. And in the Sacramento River tests, Twister emerged from the water on some run by climbing banks measured at over 60 per cent in slope. In the river trials. Twister climbed slick mud banks up to 40 per cent.
"Twister's flexibility and its ability to operate in soft soils is the key to he vehicle's successful water entries and exits, "said John Plummer, Lockheed's Army vehicle program manager. "And the water jet is responsible for the good speeds we obtained afloat."
Plummer explained that the water jet, which is powered by the engine in Twister's rear body, has to thrusters located on each side of rear body. The vehicle's driver can control deflectors to alter the thrust from full ahead to full reverse.
In trial runs in a test tank at the Lockheed plant in Sunnyvale, the 18-foot-long Twister was able to turn completely around in 20 feet.
"Water jets are greatly superior to propulsion with only wheels or tracks, as used on most military vehicles, "said Plummer. "With a properly designed water jet we can make a land vehicle truly amphibious with a minimum of compromise to our design for high performance cross country operation."
The Army Twisters are designed to ford in water 42 inches deep. Prior to delivery to the Army, the XM 808 armoured fighting vehicle spent several days running in lake-side marshes on Lockheed's test course in the Santa Cruz Mountains, but the recent trials marked the first time any Twister has been operated as a swimmer.
Lockheed developed the Twister concept in 1964 and produced its own test vehicle in 1965. The original Twister has operated successfully in mountains, deserts, sand, snow, marshes, rice paddies, and more recently on the barren wastes of Alaska's North Slope, 200 miles north of Arctic Circle.