How Do You Calculate Acceleration at Different Points on a Helicopter Rotor?

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SUMMARY

The calculation of acceleration at different points on a helicopter rotor involves understanding both centripetal and tangential acceleration. Key parameters include the rotor's diameter (d), rotor length (l), flapping angle (theta = A sin(omega*t)), and rotation speed (Omega). The discussion emphasizes the importance of using polar coordinates to analyze the motion, particularly as the position of a point on the rotor changes, affecting both its radius and tangential velocity. The acceleration experienced by a point, such as a worm moving from the tip towards the hinge, varies due to these changes in radius and velocity.

PREREQUISITES
  • Understanding of circular motion and centripetal acceleration
  • Familiarity with polar coordinates in physics
  • Knowledge of angular motion concepts, including rotation speed (Omega)
  • Basic trigonometry for calculating angles and sine functions
NEXT STEPS
  • Study the principles of centripetal acceleration in rotating systems
  • Learn about tangential acceleration and its calculation
  • Explore the application of polar coordinates in dynamics
  • Review the mathematical derivation of the flapping angle in rotor dynamics
USEFUL FOR

Aerospace engineers, physics students, and anyone interested in the dynamics of rotating systems, particularly in the context of helicopter rotor mechanics.

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How would you calculate the acceleration of the following two points?

http://img341.imageshack.us/img341/917/helicoptor.jpg
Uploaded with ImageShack.us1) The tip of the helicopter blade

The diameter of the hub = d
The length of the rotor = l
The flapping angle: theta = A sin(omega*t)
The rotation speed of the rotor system = Omega2) A warm crawling from the tip to the hinge

The current position from the hinge = x
The speed along the blade = v (inward)

I'm trying to find the acceleration by the method of moving frame and it's getting tricky...
 
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In the picture shouldn't that be d/2 rather than 2/d as the radius from the centre to the hub edge?
Out of curiosity, what is A?

Nonetheless, in what direction would the worm feel an acceleration?
If the worm has moved to another position closer to the hub, how has the acceleration that it feels changed?
I think if you set up your equations regarding centripetal acceleration you should be able to solve.

As the worm moves inwards, the radius is changing (as above) so the worm's tangential velocity is also changing. Thus there is also a tangential acceleration, which you can solve for.

You could try using polar coordinates.
here is a description from Wiki
http://en.wikipedia.org/wiki/Circular_motion
 
Last edited:

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