Screw-propelled vehicles use auger-like cylinders for propulsion. The cylinders have a helical spiral flange, like a screw thread. The motion works like this:
They were briefly desirable for vehicular propulsion over snow and extremely rough terrain. Because the screws were hollow, they could also be used as floats for amphibious vehicles.
Fordson tractor converted into screw-propulsion:
1926 Armstead Snow Motor vehicle:
Chrysler developed the Marsh Screw Amphibian for the Vietnam War. It performed excellently through water and marshy terrain, but failed on firmer ground:
The Russians built the ZIL-2906 for recovering the re-entered Soyuz space capsules from extremely difficult terrain:
Although they never took off, screw-propelled vehicles still see extremely narrow usage today for specialized construction in unusual climates. Also, the occasional daring offroader will try a screw-propelled build:
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