Laboratory Simulation of Landing Gear Pitch-Plane Dynamics

A technique for laboratory dynamometer simulation of landing gear-brake dynamics is discussed. The method was developed as a means of improving certain limitations of conventional dynamometer testing with and without actual strut hardware. The test fixture, the basis for its similitude, assumptions, and design criteria are described. Background includes descriptions of the form and significance of brake-induced vibration and the concept of a critical torque-speed slope as it relates to system stability criteria. Use of this fixture enables the duplication of brake squeal modes otherwise masked by standard dynamometer fixturing. The large linear range of amplitude and damping permit operation in a deliberately unstable condition to verify stability margins. Examples of the application and verification of the technique are included.