apollo11 wrote:Once this happens is it game over right there or can the pilot throttle back and pitch up very gently to recover?
If a retreating blade stall is severe enough that blade flap occurs in flight beyond the limits of the teeter stops, i.e. causing the gyro to roll left in the sky it is pretty much game over. Prevention is better than cure! This is the reason for the very clearly marked VNE limits.
apollo11 wrote:How robust are the bearings in the rotor head? How robust is that teeter bolt? What are the enhances of the rotor head seizing (not related to this accident just general questions)
The rotors on a (modern 2 seater) gyro rotate at a relatively low RPM, normally approx 350-450 RPM during flight. Thus the rotor head bearings are not working hard and the bearing temp tends to be only a degree or two above ambient temperature. The teeter bolt is very robust. Assume an LSA max all up weight of 600kg the most g-force you could pull is less than 3g giving a total weight on the teeter bolt of around 1.8 tons. Some of the gyros have teeter bolts rated to 25 tons. The chance of a rotor head seizing is small enough to be completely discounted (assuming of course that servicing and maintenance has been carried out to factor standards by an approved person). One of the longest flying modern gyros is the Magni and to the best of my knowledge they have not had a single incidence of a rotor head failure in all their years of operation.