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Aerodynamics

15 tools in 6 sections. Each tool page shows the method with the numbers substituted, its references and the published examples it reproduces.

Airfoils and Wings 1

  • Airfoil and Wing Lift Section and wing lift from thin-airfoil theory and Prandtl's lifting line: the zero-lift angle, ideal angle, design lift coefficient and quarter-chord moment of a NACA…

Rotors and Propellers 9

  • Ducted Fan Optimization
  • Ducted Fan Performance Thrust, torque, power and figure of merit of a ducted fan whose blade geometry is known, from blade-element momentum theory: the chord and pitch at a few stations from…
  • Duct Thrust Share Momentum theory of the ducted fan: how the thrust divides between the rotor and the duct lip, the induced velocity at the disk, the exit velocity, the ideal power and…
  • Fan Motor Matching Operating point of a ducted fan on a brushless DC motor: where the motor's torque-speed line meets the fan's torque curve.
  • Multi-Fan Vehicle Sizing First-order hover and climb power budget of a vehicle lifted by several ducted fans: from the takeoff weight, the number of fans, their diameter and exit area ratio, the…
  • Fan Noise Estimate Far-field noise of a fan or propeller from its thrust, shaft power, speed, diameter, blade count and blade area: the rotational (tonal) noise of the first harmonics of…
  • Tip Clearance Loss What the gap between the blade tips and the duct wall costs a ducted fan: the fall of the hover figure of merit and of the thrust-to-power ratio with the tip clearance…
  • Inlet Flow and Crosswind A ducted fan in a crosswind or in forward flight sees the free stream at an angle to its axis.
  • Fan Blade Stress Centrifugal force, flapwise and lagwise bending moments, combined stress and the first bending frequencies of a ducted-fan blade from its planform, section, material and…

Aircraft Performance 2

  • 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.
  • 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…

Stability and Control 1

  • Longitudinal Static Stability Stick-fixed longitudinal static stability and trim of a conventional airplane from its wing, fuselage and horizontal-tail data: the airplane lift-curve slope, the…

Atmosphere and Flight Conditions 1

  • Standard Atmosphere and Airspeeds Temperature, pressure, density, speed of sound and viscosity of the U.S. Standard Atmosphere, 1976 at any geometric altitude to 86 km, with an optional ISA temperature…

Propulsion 1

  • Propeller and Jet Thrust Thrust and efficiency of the three classical propulsion models, chosen by a select: the Rankine-Froude momentum theory of the propeller disc (induced velocity, ideal…