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Several test standards exist for measuring lift truck sound levels, both for operator's ear sound levels and exterior (sound power) levels. All of the test standards result in the reporting of a single-number sound level that is a weighted average of the measured sound levels in various operating modes. This paper presents the results of calculations based on actual measured data that clarify the sensitivity of the reported sound levels to the sound levels in the individual modes. The results show that for both of the common operator's ear noise test standards, the reported sound levels are typically very insensitive to the idle sound level even though the idle sound level is given a much higher weighting factor than the other modes. Also of interest are the lift truck sound power test standards. The test procedures include a driving test mode that is derived from the ISO 6395 earthmoving machinery test standard.

The traction and wear problem for a main landing gear tire of the Space Shuttle Orbiter is considered. Side force acting on the tire during landing under yawed conditions, and the associated tire wear, are computed using analytical expressions derived from basic principles of physics. These equations relate side traction and wear to vertical contact load, slip angle, tire mechanical properties, footprint geometry, and rubber abradability. Numerical results in graphical form are presented for side force as a function of slip angle at various tire loads and compared with values obtained using the empirical formula of Dryden Flight Research Center (DFRC). Energy dissipated by the side force is used as a tire-wear index, forming the basis for deriving bilinear tire wear models for both the Kennedy Space Center (KSC) and Edwards AFB runways. The constants of these models are determined using Convair 990 (CV 990) Landing Systems Research Aircraft (LSRA) test data.