To: 4 dogs
Please note the following paragraph.
“You can address the end result and quote all types of engineering speak but until I can get this question resolved by Bell I will continue to believe that the 2 per rev bounce is caused by the intermittent loss of lift as the blades rotate. If Bell says it ain’t so I’ll go on to other pastures”.
The original theory of the blades decreasing lift, as they became disposed over the centerline is not mine. It is from the accumulated uttering of Bell test pilots and other pilots of Bell helicopters. Now, they may have been wrong in their conclusions and maybe I am wrong for espousing those theories but until the fat lady sings (Response from Bell service engineering) I have to stick with it.
To: All
Answer this question: What kind of vibration can cause a 600-800 pound transmission to move up and down at two times the rotor speed? What forces are at play that can cause this kind of movement? Where are those forces generated?
To: 212 Man
In the situation you described above you answered the question. In your description you stated that there was no forward speed and therefore, the blades were lifting equally. However when the helicopter comes up to speed the condition I described will (assumedly) take place.
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The Cat
[This message has been edited by Lu Zuckerman (edited 25 June 2001).]
[This message has been edited by Lu Zuckerman (edited 25 June 2001).]