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This report summarizes the experimental research conducted at the NASA Langley Research Center on general aviation seat and occupant crash response and discusses seat design considerations. Included are typical floor acceleration pulses from general aviation airplane crash tests, the performance of typical general aviation seats in a simulated crash environment, and the performance of prototype energy absorbing (EA) seat designs. Static and dynamic seat testing procedures and test facilities are discussed. Also presented are results from a series of dynamic tests of typical general aviation seats and prototype EA seats.

The vortex flowfield over an advanced twin-tailed fighter configuration was measured in a low-speed wind tunnel at two angles of attack. The primary test data consisted of 3-component velocity surveys obtained using a laser doppler velocimeter. Laser light sheet and surface flow visualization were also obtained to provide insight into the flowfield structure. Time-averaged velocities and the root mean square of the velocity fluctuations were obtained at two cross-sections above the model. At 15 degrees angle of attack, the vortices generated by the wing leading edge extension (LEX) were unburst over the model and passed outboard of the vertical tail. At 25 degrees angle of attack, the vortices burst in the vicinity of the wing-LEX intersection and impact directly on the vertical tails. The RMS levels of the velocity fluctuations reach values of approximately 30% in the region of the vertical tails.

High-angle-of-attack flight dynamics of the X-29 configuration were studied using dynamic model test techniques. These tests identified phenomena including wing rock, spins, and tumbling which dominate the high-α behavior of the configuration and define its usable flight envelope. Results of these tests have been used to design flight control concepts to minimize adverse behavior. Planned high-angle-of-attack flight tests of the X-29 airplane will provide an opportunity to validate the model predictions.

A brief history of stall/spin technology for light general aviation airplanes and proposed criteria to describe desirable characteristics of a spin-resistant airplane are presented. Flight tests of a representative light airplane to evaluate compliance with and usefulness of the criteria are presented. The baseline airplane configuration would not meet the spin resistance criteria. Tests of the airplane with a wing leading edge modification to enhance its spin resistance showed compliance with the proposed criteria.

Correlations for transition from laminar to turbulent flow on 45° and 60° swept cylinders based on data obtained in the NASA Langley Mach 3.5 Pilot Quiet Tunnel are presented. Variations of free-stream noise from high levels comparable to those in conventional wind tunnels to more than an order of magnitude lower had no effect on transition. However, when boundary-layer trips were attached to the leading edges, transition occurred at lower Reynolds numbers depending on both the trip height and the wind tunnel noise level. Compressible linear stability calculations have been performed for the boundary layer on an infinite swept cylinder. The boundary layer on the attachment line has a generalized inflection point similar to that present in a flat-plate boundary layer. The results show that Tollmien-Schlichting waves are amplified in the attachment line boundary layer and that oblique waves have the highest growth rates. Wall cooling tends to be stabilizing.