To: Baque Flip, Grey Area and everybody else that I have tried to force my beliefs on.
Our arguments are like trying to convince the other guy that your religion is better than his. You believe in God and he believes in Allah. You believe in Jesus Christ as being the Messiah and your Jewish neighbor believes that the Messiah is yet to come and when he does come, most likely he will find that it is Jesus Christ. When you get to heaven or your Muslim friend gets to Paradise and you meet up there you find that one god is judging you. What you see suits your beliefs and what the Muslim sees suits his belief. You both believe in the same thing but you see it in different ways.
What you learn about helicopters in the UK training programs suits you very well and you have a complete understanding of the subject. The student and pilot in the USA training programs gets a different understanding and that suits them very well, and they have a complete understanding of the subject. As long as you stay in the UK and the American stays in the States every thing is OK. Switch places and your whole concept about how a helicopters flies will immediately come under challenge.
I think Grey Area said it, it is a difference in language. I have often wanted Danny to incorporate a Lexicon or, thesaurus so that us Yanks understand what you Brits and especially the Wizards of OZ are talking about.
I think we should bring this aspect of these threads to a halt. No more talking about precession or phase lag.
I just received this from a pilot in the UK. I asume he was trained in the military.
It explains everything.
One aspect of rotor control that is not taught in the British Military is that of the rotor system acting as a gyroscope. Our belief is that the phase lag of 90 degrees exists between input of pitch change and desired blade position only because of aerodynamic forces. The blade starts to flap as the pitch operating arms follow the circular control orbit and the rate of change of pitch is at it's maximum 90 degrees later - for the next 90 degrees the blade continues to flap but at a reducing rate until at a point 180 degrees from where the pitch angle started to change - the blade reaches it's high or low point before completing the other 180 degrees doing exactly the opposite.
Whilst a theoretical solid rotor disc might exhibit some tendency to precession, the greatly reduced mass of a real rotor and the fact that the blades are free to flap mean that gyroscopic theory is not wholly applicable - are aerdynamic loads on a blade inertial or external and what produces the torque required to induce precession? - the pitch change happens gradually and is not the single point force that most textbooks illustrate when depicting precession in a gyro.
Grey Area appears to be ex-British Military, probably Navy and has questioned your use of the term "flapping to equality", we use it to describe the reaction of the blades to overcome dissymmetry of lift such as flapback or inflow roll, whereas you seemed to use it to describe the coning angle achieved once the lifting and centrifugal forces were in balance in the rotor system.
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The Cat
[This message has been edited by Lu Zuckerman (edited 21 December 2000).]