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Aircraft Performance

2 tools in the Aerodynamics area.

Aircraft Performance

Point and mission performance of a propeller or jet airplane from its parabolic drag polar C_D = C_D0 + K C_L^2 and the 1976 U.S. Standard Atmosphere: the drag and power required against speed with the parasite and induced parts, the stall, minimum-drag and minimum-power speeds and (L/D)max, the level-flight speed range where the power (or thrust) available meets the requirement, the rate and angle of climb against speed with the best-climb speeds and the hodograph, the absolute and service ceilings from an altitude sweep of the best rate of climb, the Breguet range and endurance in the propeller and the jet form, and the take-off and landing distances by segments (ground roll from the integrated equation of motion of NACA TN 1258, rotation, transition arc and climb to the obstacle; approach, flare, free roll and braking), each printed with its equation and the substituted numbers. The default is a 2,400 lb light airplane with 160 ft^2 of wing, C_D0 0.025, e 0.8, AR 7.4, 180 hp at a propeller efficiency of 0.80 and a BSFC of 0.45 lb/hp-h at sea level, for which the page gives (L/D)max 13.64, a top speed of 147 knots, a best rate of climb of 1,455 ft/min, a service ceiling of 22,200 ft and a take-off of 747 ft over 50 ft, every value checked against closed forms and an independent numerical integration.

1 worked example reproduced, listed on the tool page.

Aircraft Drag Build-Up and Trim Drag

Component drag build-up of a subsonic airplane by the classical method of the USAF Stability and Control DATCOM: each component's flat-plate skin friction at its Reynolds number (Prandtl-Schlichting or Karman-Schoenherr law, Blasius laminar run ahead of an entered transition point, the compressibility factor of NACA TN 2305 or the T-prime method of NACA TN 3391, the roughness cutoff Reynolds number of DATCOM figure 4.1.5.1-27), the DATCOM form factors (wing 1 + L t/c + 100 (t/c)^4 with the lifting-surface factor of figure 4.1.5.1-28b, body 1 + 60/f^3 + 0.0025 f with the base drag of equation 4.2.3.1-b), entered interference factors and the wing-body correlation factor of figure 4.3.3.1-37, wetted areas entered or from the planform and the fuselage dimensions (NASA RP-1060), miscellaneous increments and an excrescence allowance, giving C_D0, the equivalent flat-plate area and the share of each component; the induced drag with an entered Oswald factor or the lifting-line span efficiency of the planform, the drag polar with (L/D)max and the minimum-drag and minimum-power speeds; the trim drag from the tail load that balances the pitching moment at the entered centre of gravity (the Longitudinal Static Stability tool's balance), against lift coefficient and c.g. position; and the transonic drag rise by Korn's drag-divergence Mach number and Lock's fourth-power law. The default is an illustrative light twin at 10,000 ft and 180 knots; the method is checked against the DATCOM sample problems and the NASA CR-151971 example (867 checks).

1 worked example reproduced, listed on the tool page.

Other Aerodynamics sections

Airfoils and Wings · Rotors and Propellers · Stability and Control · Atmosphere and Flight Conditions · Propulsion