Tri-star (wheel arrangement)

The tri-star is a novel wheel design—originally by Robert and John Forsyth, assignors to Lockheed in 1967—in which three wheels are arranged in an upright triangle with two on the ground and one above them. If either of the wheels in contact with the ground gets stuck, the whole system rotates over the obstruction. (Patent #3,348,518)

Its most famous application was the Landmaster, a unique armoured personnel carrier (APC) from the film Damnation Alley. Its common application is employed as a stairclimber.

Lockheed also modified an M2A2 105mm Light Howitzer from 1969-1977 with a drive unit and tri-star wheel system into an Auxiliary Propelled Howitzer they termed "Terra Star." The only surviving prototype is located at the Rock Island Arsenal Museum

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