1367. PARAM – A New Weight-Sizing Routine


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T R Smith: 1367. PARAM – A New Weight-Sizing Routine. 1980.



A need has long existed for a low-cost sizing routine for use in initial stages of aircraft design. To fill this void, MCAIR has developed a new scaling routine for its mission and performance program. The goal of this routine is to scale an initial baseline aircraft to the proper wing area and engine size combination to achieve a given set of performance or weight requirements. Figures of merit include takeoff weight, fuel weight, mission radii, with various wing loading and thrust-to-weight ratios at takeoff. Because required inputs are also kept to a minimum, program costs are low. After using this routine to ‘home in on’ the proper sizes, additional refinements can be obtained using a more detailed scaling approach.
This paper outlines this new weight scaling subroutine used in the MCAIR Advanced Design section. The basic ideas behind its scaling procedure will be shown, while no attempt will be made to explain the aerodynamic or propulsion performance aspects of the main program. The primary required inputs are identified. Figures of merit with typical results of the subroutine will then be given.


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