Projects:EASA PPL/Aircraft General Knowledge

Mechanical

• Flutter: torsion + bending
• Shimmy: sinusoidal motion/vibration + damper
• Trim tab:
  • reduce/cancel control forces
  • reduces hinge moment
  • reduces control surface efficiency

Fuselage & General Design

• Stringers: assist the skin withstand longitudinal compressive loads

• Wing spar: web + girders
• Truss framework: used in light training aircraft
• Monocoque: skin takes all the load
• Semi-Monocoque: skin, frames, stringers -> skin takes majority of the load
• Safe Life Design: may be used for number of cycles or flight hours

Landing Gear

• Recoil: Pressurized Air or Nitrogen
• Dampener: Oil

Controls

• Yaw pedals: control heading, balance, slip and skip

Propeller

• Blade tip is moving faster than blade root -> Prop is twisted, so that angle of attack stays the same at the tip
• Constant Speed Propeller:
  • Pitch angle increases with increasing true air speed
  • manifold pressure increase -> prop pitch angle will increase
  • Engine failure: prop moves to lowest pitch, due to centrifugal force / spring force
• Slipstream effect of Prop: at low airspeed with high power

Electrical

• Electrical ice protection: prevent ice on small surfaces
• Static dischargers: on wing and tail tips for electrical discharge + reduce radio interference, limit transfer of electrical charge from clouds
• Circuit breaker
  • Thermal: regular, slow
  • Magnetic: faster

Engine

• Otto motor:
  • Diagramm: 2 adiabatic + 2 isochoric lines
  • Ignition before TDC (top dead center) at each second revolution
• Max EGT is associated with mass ratio of 1/15
• Carburettor ice with fixed prop: turn carb heat on, decrease in RPM -> increase in RPM
• Gearbox: magnesium alloy
• Monitor engine power: RPM meter

Magneto

• Magneto impulse coupling: stronger spark at TDC for engine starting, retarded spark
• Magnetic field flux: a conductor cuts the flux of a magnetic field -> emf is induced in the conductor

Flaps

• Trailing edge flaps: increase lift at a lower angle of attack

Compass

• True heading -> Magnetic heading: use variation (from map with isogonal lines)
• Magnetic compass: turning error due to vertical component of earths magnetic field
• Compass check swing: measure the angle between magnetic north and compass north
• Compass indication on acceleration or deceleration
  • ANDS - Accelerate North - Decelerate South

Altimeter

• Density altitude: the altitude of the standard atmosphere on which the density is equal to the actual density of the atmosphere