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05-A: Steep Turns

Knowledge

K1: How to conduct a proper steep turn

  • altitude
    • required to maintain altitude:
      • backpressure on the yoke to increase in lift (AoA) to refill lift used for turning
      • maintaing awareness of flight instruments to initated corrections

K2: Aerodynamics assocaited with steep turns, including

K2a: maintaining coordinated flight

K2b: overbanking tendencies

K2c: maneuvering speed, including the impact of weight changes

  • Va: maneuvering speed
    • max speed for steep turns
    • not marked on the airspeed indicator

K2d: load factor and accelerated stalls

  • load factor

    • is determined by bank alone
      • load factors per bank angle
        • 45°: 1.41 g
        • 60°: 2 g
    • also abruptness of attitude changes
    • answer for one question also includes weight which is debatable

  • Velocity vs G-Loads (Figure 7.2)

    • indicated axes:
      • horizontal axis: airspeed
      • vertical axis: load factor (lift / weight)
    • vertical E to F: Vne, never exceed speed, red line
    • C via D to E: positive limit load factor

K2e: Rate and radius of turns

Knowledge

"mnemonic" Vx < Vy Vs0 < Vs1

speeds - Vs0: stall speed at landing configuration (full flaps, landing gear dow) - marking on the airspeed indicator: - lower limit of the white arc

  • Vs1: stall speed at clean configuration (flaps up, landing gear up)

  • marking on the airspeed indicator:

    • lower limit of the green arc

  • Vref: 1.3 x stall speed

  • Vapp:

  • Vx: best angle of climb

  • Vy: best rate of climb

  • Vg: best glide

  • Vfe_max: maximum allowed airspeed at full flaps (flaps 30/40)

  • marking on the airspeed indicator:

    • upper limit of the white arc

  • Vfe_10: maximum allowed airspeed at flaps 10

  • Vno: normal speed/maximum structural cruising speed/smooth air speed

  • definition
    • speed only top be exceed in smooth air
  • explanation
    • downdrafts in turbulences can bend the wings
  • difference to Va:
    • Va protects you from cracking the wings from pulling too hard
    • Vno protects you from cracking the wings from going too fast through bumps
  • indication on the airspeed indicator:
    • transition from green to yellow

Vne

  • load factor n in a level turn
  • dependes on the bank angle, not the airplane speed or airplane type
  • n = L / W where L is lift (= air load) and W is aircraft weight
  • in a level turn, the total lift L is decomposed in vertical (L \cdot cos(theta)) and horizontal component (L \cdot sin> (theta) )
  • computation of load factor is independent on airspeed or specific aircraft
  • computation of n in a bank: n = 1 / cos(theta) (https://chatgpt.com/c/681e2879-0e30-8001-bfe5-a0baec8f393a)
    • 45 degs: 1.41
    • 60 degs: 2
  • accelerated stalls
  • overbanking tendencies
  • rate and radius of turn

metadata 1) call out heading, altitude, visual reference

clearance 2) clear by vision and 2x90deg turns

stabilze 3) slow down to maneuvering speed (95 knots) and trim

roll-in 4) add 100 RPM 5) roll into the steep turn (DON'T DROP THE NOSE OR YOU'LL LOSE ALTITUDE)

bank maintenance 1) keep bank stable, keep altitude (unroll and pull for climb), keep ball centered

roll-out 2) 20 degrees before target heading, use ailerons AND rudder in the same direction to roll out of the turn

**notes given the low-speed, high-power setting in a steep turn, the left-turning tendency is usually more pronounced that the turn-induced slip, so even in a left turn, a bit of right rudder might be need =