Experimental Results and Analysis of Aircraft Tire-Test Drum Interaction

Abstract

Abstract Although aircraft tires are traditionally tested on external drum dynamometers, the effects of the curvature of the test surface on the normal contact pressure distribution and footprint area of an aircraft tire have not previously been addressed. Using the tire force machine (TFM) at the Wright Laboratory Landing Gear Development Facility (LGDF), trends in tire footprint area and normal contact pressure distributions were investigated for concave, flat, and convex surfaces. This evaluation was performed using the F-16 radial (25.5×8.0 14PR) main landing gear tire at rated load (16,200 lbf) and inflation pressure (310 psi). The trends for overall tire footprint behavior indicate that the more convex the surface, the smaller the contact area and the larger the normal contact pressure. Conversely, the more concave the surface, the larger the contact area and the smaller the normal contact pressures. All data were made symmetric about the longitudinal and lateral centerlines. This process and its effect on the data are discussed at length in the analysis sections. Additionally, it was found that after normalizing the normal contact pressure data with respect to contact length and maximum pressure for the individual tire ribs, the normal contact pressure longitudinal distributions were “identical” (within ±5%) regardless of surface curvature. Comparisons are made with numerical experiments on a treadless, homogeneous polyurethane automobile tire.