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This paper describes a finite-difference method for unsteady transonic flow computation in frequency domain and transonic flutter prediction of complete aircraft configurations. The unsteady TSD equation as well as the boundary conditions are split into the in-phase and out-of-phase components in frequency domain by a nonlinear harmonic averaging technique. The resulting equations are solved by a steady flow algorithm. The unsteady pressure distributions for a rectangular wing and the ONERA M6 wing are analyzed and compared with other results to verify the code. The flutter characteristics for the AGARD I-445.6 wing, a cropped delta wing and a fighter configuration are computed and the results are discussed.

Aerodynamic effects induced from vectoring an exhaust jet are investigated using a well established thin-layer Reynolds averaged Navier-Stokes code. This multiple block code has been modified to allow for the specification of jet properties at a block face. The applicability of the resulting code for thrust vectoring applications is verified by comparing numerically and experimentally determined pressure coefficient distributions for a jet-wing afterbody configuration with a thrust-vectoring 2-D nozzle. Induced effects on the body and nearby wing from thrust vectoring are graphically illustrated.

The present status and flight-test results are presented for the ATLIT airplane. The ATLIT is a Piper PA-34 Seneca I modified by the installation of new wings incorporating the GA(W)-1 (Whitcomb) airfoil, reduced wing area, roll-control spoilers, and full-span Fowler flaps. Flight-test results on stall and spoiler roll characteristics show good agreement with wind-tunnel data. Maximum power-off lift coefficients are greater than 3.0 with flaps deflected 37°. With flaps down, spoiler deflections can produce roll helix angles in excess of 0.11 rad. Flight testing is planned to document climb and cruise performance, and supercritical propeller performance and noise characteristics. The airplane is scheduled for testing in the NASA-Langley Research Center Full-Scale Tunnel.

A wind tunnel investigation was made of a new high-lift system consisting of a leading edge cusp flap combined with split upper and lower trailing edge flaps. The idea behind the system was to generate two strong spanwise vortices that would increase maximum lift and drag simultaneously. Test results were not encouraging. The spanwise vortices were observed, but were not sufficiently strong to generate the anticipated high lift. Several interesting flow phenomena were observed and are described. The purpose of this paper is to present a summary of results obtained from this wind tunnel test program.

Significant progress has been made in several areas of research relating to general aviation technology at the University of Kansas. This paper describes the design and operation of the major systems of a fixed-base visual and instrument flight simulator, now operating as a valuable research tool in configuration analysis, handling qualities research, control system and cockpit design studies, and other areas. Also included is a report on the status of a NASA sponsored project on improvements in light aircraft design, with attention focused on the wing design, high lift systems, spoiler lateral controls, and a direct lift system. Results of theoretical and wind tunnel studies in these areas are being incorporated in a Cessna 177 Cardinal for an extensive flight test program next year. A brief discussion is also given of two projects recently initiated which will investigate the use of separate auxiliary control surfaces for stability augmentation and for gust alleviation.

A parametric investigation was made to determine which aerodynamic design modifications can be made to improve significantly the performance of light airplanes. The study was made around a typical low wing and a typical high wing airplane. Performance parameters selected for comparison with the baseline configuration are: speed for best range, maximum level speed, specific range, maximum rate of climb, and speed for maximum rate of climb. It is shown that significant improvements in these performance parameters are possible by aerodynamic refinements. It is also shown that by application of modern high lift technology significant improvements in take-off and landing performance can be obtained. A similar analysis was employed to improve stability and handling characteristics such as spiral stability, dutch roll stability, and gust response.