IFMU, that pusher prop windmill brake power comment has been removed since i realise it was probably in error. [edit 23Feb08]
However, a potential advantage is that the pusher prop could be used to pull energy out of the airstream. The immediate advantage would be a lack of need to drop collective and flare in autorotation from cruise. This would also means that the main rotor would not have to be at flat pitch during autorotation, with forward cyclic, to allow good yaw authority. Coaxials can suffer reduced yaw control in autorotation, as the differential collective pitch does not transfer torque as when in level flight.
I imagine the pusher prop has an additional twist grip on the collective. Alternately the system may automatically trim the prop for all flight conditions. The system has good potential.
Once the machine has been tether tested, and the flight testing gently expands the envelope, i'm sure the TPs will have all sorts of interesting information. I for one will be very keen to learn and understand the TP feedback.
CEFOSKEY, I imagine all the engineers are mildly frustrated at the moment not having access to the X2. Prototype access is always a balance between the marketing department and development. Still at least the design breif of "take your time" means the X2 design can progress in a sensible manner - it is not always so.
