To: Dave Jackson
I believe that most tail rotors have a delta-3 of 45-degrees. This means that any flapping is instantly pulled out. No 90-degrees. No discernible delay. .
Edited to remove the words no !!!!.
On two blade tail rotors the delta hinge is offset by 60 degrees. You say that any flapping is instantly pulled out. Please explain. When the tail rotor flaps one blade will decrease in pitch and the opposite blade will increase in pitch thus equalizing the lift across the tail rotor disc. On multi blade tail rotors that are free to flap the blades act like those on the main rotor. When the blade flaps in either direction the pitch flap coupling will tend to return the blade to the radial position. This is a form of relieving stress on the blades and that’s why they are free to flap. However with flapping you get lead an lag and this is catered to by the design of the blade (S-58 , S-61) or by the incorporation of a lead lag hinge and a damper (CH-37).
