Helicopters and Angular Momentum

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Discussion Overview

The discussion revolves around the mechanics of helicopter flight, specifically focusing on how helicopters counteract the torque generated by their main rotor blades and the role of the tail rotor. It includes technical explanations and personal anecdotes related to flying helicopters.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants explain that the tail rotor's main function is to counteract the torque applied to the main rotor and to control the helicopter's orientation.
  • Others elaborate that the tail rotor counteracts torque along the main rotor axis (yaw), and that a helicopter must lean towards the thrust side of the tail rotor to achieve a true hover.
  • One participant mentions the gyroscopic effect of the main rotor, which results in a pitch reaction to roll torque, indicating that pilot controls must be adjusted accordingly.
  • Some participants recommend a book, 'Chickenhawk', for a vivid description of flying a helicopter, suggesting that it captures the experience of piloting a Bell Huey effectively.

Areas of Agreement / Disagreement

Participants generally agree on the function of the tail rotor in counteracting torque and controlling the helicopter's orientation, but there are nuances in the explanations and additional insights that remain unaddressed. The discussion includes both technical details and personal experiences, leading to a mix of agreement and individual perspectives.

Contextual Notes

Some claims about the mechanics of helicopter flight depend on specific definitions and assumptions about rotor dynamics and pilot control techniques, which are not fully explored in the discussion.

azabak
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How does an helicopter counteract the torque generated by its blades?
And the tail blades, what are they for?
 
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The main function of the tail blade (rotor?) is to counteract the torque applied to the main rotor. You can also use the tail rotor to control where the helicopter is pointing. If you lose drive to the tail rotor (/fan / nozzle) you are in real trouble.
 
azabak said:
How does an helicopter counteract the torque generated by its blades? And the tail blades, what are they for?
The tail rotor is used to counter act the torque along the main rotor axis (yaw). This results in a net force to one side, so a true hover requires a helicopter to lean a bit towards the thrust side of the tail rotor.

The gyroscopic effect of the main rotor results in a pitch reaction to roll torque and vice versa. The pilot pitch and roll controls end up being advanced by 90° along the rotor axis to compensate for this.
 
Last edited:
For the best description, ever, of all this, read the first couple of chapters in 'Chickenhawk' by an ex Vietnam Chopper pilot. He describes learning to fly a Bell Huey and leaves you, the reader, sweating and with palpitations as if you're actually in the pilot's seat. No fly-by-wire in those days.
 
Oh, I see. Thanks you guys!
 
sophiecentaur said:
For the best description, ever, of all this, read the first couple of chapters in 'Chickenhawk' by an ex Vietnam Chopper pilot. He describes learning to fly a Bell Huey and leaves you, the reader, sweating and with palpitations as if you're actually in the pilot's seat. No fly-by-wire in those days.

Although it's the last paragraph of the book that really sticks with you...
 

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