Journal of Aviation/Aerospace Education & Research


John T. Lowry






The Bootstrap Approach (TBA) to fight performance is, for fixed-pitch propeller-driven airplanes, a set of simple formulas in nine aircraft parameters-four from brief flight tests-plus the variables of aircraft weight and air density. The formulas are derivable from the empirically supported linearity of the propeller polar. TBA outputs include five full-throttle or gliding V-speeds (Vx Vy Vm Vbg Vmd) and a common version of long range cruise speed (VLRC) as well as, for any air speed, thrust, drag, rate of climb (thereby service ceiling) or descent, and flight path angle. Knowledge of engine speed (RPM) and fuel consumption rate allows calculation of (partial-throttle) speeds Vbr for best range and Vbe for best endurance. An extension of TBA to airplanes with constant-speed propellers substitutes two different propeller parameters and suggests a general propeller chart. Though based on empirical graphs rather than formulas, this extension easily incorporates partial-throttle operation.



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