Spiral Dive v.s Spin v.s Dutch Roll

July 12, 2025

好耐無溫書…係時候準備! 今日朋友講起呢兩個TOPIC…就睇下啦~ XDDD

Spin

  • Stall -> Spin (autorotation)
  • BOTH wing stall, but one wing stall more -> i.e uncoordinated stall / imbalanced stall
  • 3 Phases (2 mins 36 sec)
    • Incipient Spin
    • Fully developed
    • Recovery
  • Feature
    • slow airspeed at fully developed stage + high AOA
  • Factors affecting spin recovery
    • Weight & Balance -> CG aft, more easy to spin and more sluggish to recovery
    • Weight & Balance -> heavier, longer time to recovery
    • higher -> air den less, more time to recovery
    • flaps application -> flatter spin , rudder less effective, and even cause damage!
    • power on -> increase airspeed, more altitude loss during recovery, and more time to recover
  • Recover 口訣 PARE
    • Power – to idle
    • Aileron – to neutral
    • Rudder – opposite to spin direction
    • Elevator – forward to neutral

呢到我不禁唸返當年做STALL EXERCISE…個INSTRUCTOR 講明叫我入左STALL 之後吾好扭個aileron, 但人性就係會咁…所以呢個日後真係要記住…train 個muscle memory to aileron neutral !!!

 

Spiral Dive

  • “controlled” high speed descent turn
  • common cause by incorrect elevator usage
  • Features
    1. excessive bank angle
    2. increase in Airspeed
    3. increase rate of descent

 

Dutch Roll

  • related to stability design on swept wing (lateral stability > directional stability)
  • trigger by “a disturbed roll or yaw”
  • tilted lift -> sideslip
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