A series of landings has 11.0031 made with a large- bomber type airplane equipped with twin vertical 'tails to determine the time history of the impact forces on the landing gear and the resulting response of the airplane structure, particularly that of the horizontal tail, to the landing loads. About 50 landings were made, including normal, braked, and prerotation landings, but complete time histories were obtained for only 23 landings. The quantities measured included the vertical and drag components of the landing-gear loads, landing-gear deflection, stabilizer bending moments, structural accelerations, and airplane velocity and attitude. The tests were undertaken to investigate the specific, causes of stabilizer failures on early models of the airplane, and it was found that the inaid.mum stabilizer loads occurred in normal landings as a result of -resonance -With fore-and-aft landing-gear vibration. The data presented are adaptable-'to-use in the analytical solution of the problem of structural response during;landing impacts.
展开▼
