Prediction of Aircraft Ground Performance by Evaluation of Ground Vehicle Rut Depths
Final rept. Jan-Jul 1973
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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Two single aircraft tires 20-20, 22-PR and 49-17, 26-PR and three standard military trucks were tested under towed nonpowered, nonbraked and self-powered conditions, respectively, in buckshot clay test beds whose strengths ranged from about 110 to 600 cone index. Tests included multiple passes over the prepared test beds usually 100 passes for the aircraft tires, 10 for the trucks at low speeds. Only single-wheel configurations were examined i.e., outer second- and third-axle wheels of the M35A2 and M51 were removed. Curves were developed to allow soil strength airfield index to be estimated directly from the rut produced by single or multiple passes of any of the three trucks. These curves were developed through use of a dimensionless prediction term tire-clay numeric Nc that allows pneumatic tire performance to be scaled over a wide range of soil strengths, wheel loads, and tire size, shape, and deflection conditions.
- Soil Mechanics