Specifically, a flight program to measure atmospheric turbulence at high altitudes (long wavelengths) in a variety of meteorological conditions is described and some results obtained in high-altitude wind shear are discussed. Results are also presented from wind-tunnel test programs to measure fluctuating pressures associated with over-the-wing engine configurations. Two analyses, a flexible ai...

A detailed assessment of the acoustic performance of several noise reduction concepts for aircraft flaps and landing gear is presented. Consideration is given to the best performing concepts within the suite of technologies that were evaluated in the NASA Langley Research Center 14by 22-Foot Subsonic Tunnel using an 18% scale, semi-span, high-fidelity Gulfstream aircraft model as a test bed. Mi...

This paper presents results of an unsteady Reynolds-averaged Navier-Stokes simulation of a landing-gear flow field. The geometry of the four-wheel landing-gear assembly consists of several of the fine details including the oleo-strut, two diagonal struts, a door, yokes/pin and a flat-plate simulating the wing surface. The computational results, obtained by using 13.3 million grid points, are pr...

This paper investigates the feasibility of using machine learning algorithms to predict the loads experienced by a landing gear during landing. For this purpose, results on drop test data and flight test data will be examined. This paper will focus on the use of Gaussian Process regression for the prediction of loads on components of a landing gear. For the learning task, comprehensive measurem...

This paper discusses the insights that a bifurcation analysis can provide when designing mechanisms. A model, in the form of a set of coupled steady-state equations, can be derived to describe the mechanism. Solutions to this model can be traced through the mechanism's state versus parameter space via numerical continuation, under the simultaneous variation of one or more parameters. With this ...

The ability of UAV’s (Unmanned Aerial Vehicles) to land on unknown and uneven terrain is an important area of research, particularly for applications such as field surveillance. This paper presents a novel solution to this problem using mechanical design, with a legged landing gear design that provides both suspension and stability on uneven terrain. The key features of this design are differen...

A tire and landing gear test facility has been developed and incorporated into a Convair 990 aircraft. The system can simulate tire vertical load profiles to 250,000 lb, sideslip angles to 15 degrees, and wheel braking on actual runways. Onboard computers control the preprogrammed test profiles through a feedback loop and also record three axis loads, tire slip angle, and tire condition. The ai...

Landing gear suspension systems fulfill the tasks of absorbing the vertical energy of the touch-down as well as providing passenger and crew comfort with a smooth ground ride before take-off and after landing. They are also designed to have optimal performance in the case of a hard landing. In general, the tasks of aircraft landing gears are complex and sometimes lead to a number of contradicto...