To: Dave Jackson
QUOTE: While discussing delta-3, there are two different ways of implementing it.
See the two sketches at the top of this web page.
[A/ By flap hinge geometry] has the lead/lag component in it, which you refer to.
[B/ By control system geometry] is the arraignment that Robinson uses in its main rotors.
In B above the only time there is no pitch flap coupling is when there is no collective input. At this time the pitch link / pitch horn interface is in alignment with the cone hinge. When pitch is added the pitch horn / pitch link interface will rise above the cone hinge and in this condition when the blades flap about the cone hinge you will get pitch flap coupling. The same is true when the blades flap about the teeter hinge this will also result in pitch flap coupling. So, I ask the question what is the control system geometry espoused by Frank Robinson?
