LANDING LOADS INVESTIGATION LABORATORY DROP TESTS

Airplane drop tests were conducted as part of an extensive program to compare the landing loads experienced by an A4D-2 airplane during flight tests and drop tests with those computed by analytical methods. The instrumentation used in these tests was nearly identical to that used in the flight test program and was sufficient to determine the loads applied to the airplane at the ground, the position of the strut, the in internal pressures in the gear and significant structural accelerations. The results are pre presented in the form of curves of measured parameter versus time. Vertical and horizontal loads on the gear at the ground were computed from the strut instrumentation and are compared with data from the reaction platforms. Two recommendations pertaining to the need for further work arise from this drop test program. The first is that a study of the dynamic characteristics of the reaction platforms be made in order that confidence in the instrumentation can be proved, and second, that a sliding coefficient of friction test be made of the tire on the reaction platform surface for the purpose of substantiating the high coefficients of friction registered by the left-hand strut.