Dear Joe Pilot,
I am very sorry to admit that I couldn't follow your explanation about the bicycle wheel although I know what you are talking about as I have demonstrated the same thing.
It is difficult to convey my opinions on why the Robinson helicopters should not have been certified when I am talking to an ardent supporter of the Robinson design. I can talk all day about phase angles and gyroscopic precession but if you disagree with me then It forces me to defend my position which can be difficult when I have to counter different opinions. Suffice it to say, the Robinson design should never have been certified because it does not comply with the FARs and Advisory Circular 27-1 (Certification of Normal Catagory Rotorcraft). It's all in my report and all you have to do to get it is send me your email address and if you have a fax I'll send you a diagram that explains the difference between a Bell Rotor system (which is right) and the Robinson Rotor system (which is wrong). One other point is that you mentioned a device that indicates the exact movement of the cyclic stick. Funny you should mention that. AC 27-1 paragraph 27.175.b.(1)(i) requires that a stick plotting board be used to demonstrate that the helicopter flies in the same sense as the cyclic displacement. They allow a small deviation between cyclic movement and aircraft flight direction but this is due to slight pitch coupling but not 18 degrees difference. It is this 18 degree difference that if not compensated for can introduce extremely high flapping which over time can fatigue the rotor shaft or possibly cause rotor incursions if the flapping loads are sever enough
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The Cat