Fergus has done a very good job of explaining the stability issue ( or lack thereof ) regarding gyroplanes.
What I would like to read is an explination from the British CAA as to why they can not grasp basic physics such as those involved in poorly designed gyroplanes with an excessive vertical C of G offset that will guarantee a power pushover if PIOéd or upset by turbulence which is unrecoverable and almost always results in the death of the people in the gyroplane.
As Fergus explained the addition of a functional, effective horizontal stabalizer will greatly add to the stability of a gyroplane with a high thrustline offset such as in the RAF 2000, a very popular kit gyro that has a horrendous record of killing its occupants in bunt over accidents due to PIO and or turbulence induced pitch excursions resulting in the unloading of the rotor disk and a power pushover bunt caused by simple physics.
I seldom post here anymore, however I do fly in Europe and know several British CAA inspectors in the fixed wing arena of aviation and found them to be great where safety considerations enter the operation of aircraft.
So to the individuals who make decisions regarding aircraft safety in Britian could you please explain to me why you are unable to grasp basic physics and refuse to allow the gyroplane group to improve the stability issues with reference to high thrustline gyros such as the RAF 2000. Or if you finally grasp this simple law of physics and are to inflexible to allow changes such as the addition of a H.S. why don't you ground all gyroplanes that have excessive thrustline offsets?
P.S.:
Helicopters and gyroplanes are very different breeds of flying machines and comparisons between the two can cause confusion in understanding their respective stability issues.
Chuck Ellsworth