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The faculty and staff of the Raspet Flight Research Laboratory (RFRL) have concluded a project with an industrial customer to lead a group of engineers and technicians in a study of the “art” of developing a prototype composite aircraft. The objective was to produce a turbine powered, composite, pressurized, single-engine aircraft, which would introduce the team to the many aspects of a complex aircraft in a environment. The prototype Allison Soloy turbine conversion of the Beechcraft A-36 was chosen as the study aircraft. It was proposed that the A-36 structure be replaced with composite structures in three steps of increasing complexity. The sequence was to first design-build-test-fly the tail, then the wings, and finally the fuselage. To limit the difficulty of the project development and to allow a meaningful comparison between aluminum and composite structures, the configuration modifications were to be minor and to utilize existing RFRL Marvel II composite technology.

A method is presented which permits determination of of propulsive efficiency and airplane drag terms from steady level flight speed-power data. The method is based on a computer formulation of Lock's equivalent propeller model which makes it suitable for use in parameter identification. The results are in the form of coefficients of polynomials defining the airplane and the propeller. These coefficients, determined from steady flight data, then permit easy calculation of propeller characteristics and airplane performance for other flight conditions. The method is particularly applicable to performance prediction and to simulation because the airplane and propeller are represented by a simple analytical model rather than by tables or graphs.