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The Effects of Aerodynamic Brakes Upon the Speed Characteristics of Airplanes

出版	National Advisory Committee for Aeronautics, 1949
URL	http://books.google.com.hk/books?id=mvOmYgEACAAJ&hl=&source=gbs_api

註釋A study has been made of the factors influencing the performance of aerodynamic brakes. The requirements which must be met in order for the brakes to provide the necessary control over the forward speed are discussed for various flight conditions under which they may be used. Equations relating the speed and altitude are presented for several cases in which certain simplifying assumptions are made. For these cases, formulas and graphs in the report furnish a means of quickly computing the longitudinal speed variations, the dive angles, and the rates of descent for airplanes having known drag characteristics. For the cases to which the simplifying assumptions do not apply, it is indicated that a satisfactory solution, which takes into account all of the possible variables (such as atmospheric density, drag coefficient, and flight-path angle) can be obtained by a step-by-step method of calculation. Graphs are presented to reduce the time required for step-by-step calculations. Example calculations, which show each step in detail, illustrate the use of the graphs and formulas. The increases in drag coefficient that are characteristic of several types of wing and fuselage aerodynamic brakes, which have been tested in wind tunnels or in flight, are summarized in the report. The effect of Mach number on the drag coefficient and the effect of partial brake deflection are included where such data are available.