Projects:EASA PPL/Principles of Flight

• Terminology:
  • Chord line: line from leading edge to trailing edge
  • Camber line: halfway between upper and lower surface (start: leading edge / end: trailing edge)
  • Camber: curvature of camber line (distance between camber line and chord line)
  • angle of attack (alpha): angle between chord line and free flow
  • pitch angle (theta):
  • flight path angle (gamma):
  • theta = gamma + alpha
  • angle of incidence: angle between chord line and fuselage (Anströmwinkel)
  • Induced angle of attack: result of downwash, due to tip vortices
  • Effective angle of attack: angle between chord and actual local airflow
  • Load factor: lift / weight (max for utility aircraft = 4.4)

• Bernoulli
  • Ptot = Pstat + Pdyn
  • Pdyn = 1/2 * rho * V²
• Wing aspect ratio: ratio between wing span and mean geometric chord
• Lift:
  • Lift = CLift * Pdyn(aka q) * SArea
  • Lift = CLift * (1/2 * rho * V²) * SArea
  • Coefficient of lift:
    • X Axis = Angle of Attack
    • Y Axis = Coefficient of liftb
• Drag:
  • Induced drag: result of creating lift
  • Parasitic drag:
    • Form drag: due to shape
    • Skin friction drag: surface roughness
    • Interference drag: created at junction of 2 bodies of the aircraft
    • DragP = CDrag * Pdyn * S
    • DragP = CDrag * 1/2 * rho * V² * S
• Lift + Weight + Thrust + Drag
• Stall
  • Stall speed in a turn: VStallInTurn = VStallStraight * sqrt( 1 / cos (phi) )
• Propeller
  • Gyroscopic precession - pitch and yaw