RW-1
>No, FR response made sense to anyone who UNDERSTOOD ALL the principles behind it.,
I understand very little about helicopters. It is the desire to learn that is a primary reason for participating in this and other related threads.
Thanks to Frank Robinson's posting, and some subsequent reading, things have cleared up a little. For instance, it appears that his use of the word "Wee-wa" probably stands for 'small washout'. Do you agree?
It can be assumed that Frank Robinson does not have the time, or the requirement, to publish a thesis on PPRuNe about helicopter rotorheads. Unfortunately, he addressed delta3, which is relatively common. He did not address the Robinson's unique feature. That being, the reasoning behind the combined use of a teetering hinge plus two flap/cone hinges.
In my limited capacity, I see nothing wrong with the Robinson's rotor. What I do see as wrong is threads that are intended to be technical and informative turning into personalized attacks on individuals or companies.
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Lu
You, me and probably most of the world, believe that the association between 'gyroscopic precession' and '90-degrees' is a fact.
Hopefully, the following excerpt on gyroscopic precession should be of interest.
But first, we must agree that a helicopter's rotor does not rotate as fast as a gyroscope and that the rotor's relative mass is not as great as a gyroscope's relative mass.
".............. Otherwise the motion of the gyroscope is much more complicated, as you might observe in an actual experiment where the rotation of the rotor slows down over time. We can see that as the rotor slows, the precessional frequency increases. At some point when the precessional frequency exceeds a critical value, the gyroscope will begin to wobble and eventually tumble in its gimbals." [My change to bold].
[ 16 August 2001: Message edited by: Dave Jackson ]