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Swing on take-off

Swing on take-off

  • There is often a tendency for an aeroplane to swing to one side during the take-off run. This must be due to some asymmetric feature of the aircraft, and it is an interesting problem to try to track down the real villain that is causing the swing.
  • The pilot should be the first suspect. He himself is not symmetrical, he may be right-handed (or left-handed), he probably looks out on one side of the aeroplane and may even sit on one side.
  •  Certain it is that some aircraft which have swung violently when the pilot has tried to keep them straight have gone as straight as a die when left to themselves.
  • The second and main suspect is undoubtedly the propeller. But which of its asymmetric effects is the chief cause of swing in any particular aircraft is not so easy to determine.
  • If the propeller rotates clockwise, the torque reaction will be anti-clockwise, the left-hand wheel will be pressed on the ground and the extra friction should tend to yaw the aircraft to the left.
  • But let us not forget that the torque reaction maybe compensated and, in that case, the behaviour of the aeroplane will depend on how it is compensated.
  • The slipstream – assuming the same clockwise propeller – will itself rotate clockwise and will probably strike the fin and rudder on the left-hand side, again tending to yaw the aircraft to the left. But the slipstream too may be compensated.

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