To: Heliport
The best made plans of mice and men…
Sure I have a few questions and maybe several comments.
First I would like to say I wish them much success and I see this as a normal evolution in rotary wing design.
Question 1) Is the total weight of the craft when at speed supported by the wings?
Question 2) Do they utilize flight control surfaces for control or, do they use cyclic input to control the rotor?
Question 3) Is the rotor at flat pitch when at speed. By this I mean is it aligned with the relative wind?
Comment : Relative to questions 1) 2) and 3). This aircraft is an autogyro
and could be considered a compound autogyro as it has wings and other lifting and stabilizing surfaces. One of the problems with an aircraft of this type is that if the wings are the primary lifting surfaces at speed the rotor must be aligned with the relative wind. Otherwise, the rotor would provide lift and the aircraft would be constantly rising. If for any reason the pilot or some other external force decreases the pitch on the advancing blade it could go negative and the disc would drop down at some point which would either cause fuselage contact or, loss of control.
If the aircraft uses conventional controls at speed any deviation from the flight path could cause a perturbation of the rotor mass and gyroscopic precession could change the disc path resulting in the condition outlined above. The V-22 has this problem when the PropRotors are in the Aircraft mode.
Now before anyone says I’m crazy I would suggest you check out the websites on Autogyro's and Gyroplanes as they say basically the same thing.
Based on my comment above, I would be willing to state that this condition of flat pitch and alignment with the relative wind is what did in the Cheyenne helicopter as it was maintained at flat pitch and the wings were used for lift. When the pilot input cyclic control he would never know which way the disc would tilt and how much it would tilt. This resulted in fuselage incursion on two Cheyenne’s.
These are my thoughts and if the questions are answered in a way that does not support my comment then that’s OK too. Perhaps Nick Lappos would like to comment.