On 25/01/2017 19:29, wrote:

Don't know if I should jump in here or not, but I remember a fatal
Austria accident where the pilot was attempting a full slip to
landing. Probably holding full aileron and opposite rudder as
necessary to line up with runway. As the V tailed Austria crossed the
fence, it suddenly pitched down hard and the pilot was killed. There
was some discussion about a sudden application of full rudder (one
ruddervator up, other ruddervator down) may have stalled the up
member, resulting in full down input from the remaining ruddervator.
Something to think about if flying a V tailed bird, JJ

Off topic for an HP14 thread, but I once owned a share 15m Austria SH.
You could definitely stall the V-tail with one movement (rudder or
elevator) and effectively loose all control of the other. BUT this only
happened at low speeds - well below the wing stalling speed.

It manifested itself with a few quirks. During the landing or take off
roll, if you used just enough forward elevator to lift the tail, you had
full rudder control. Any other elevator position would compromise rudder
authority. In a few other low airspeed situations, like spin recovery,
or at the top of a loop where the wings were "flying with zero G's", you
could induce V-tail quirks. But for normal flying it was no different to
flying a conventional glider.

I had no trouble with side slips but I was careful to keep the CG
position well within the handbook range. There was also a mod to the
Handbook which reduced the allowable CG range. The V-tail mounting
structure was also subject to glue joint failure, with mandatory mods. I
checked it very carefully before each flight. Also the V-tail
attachment. If one V-tail was not positively locked during rigging, the
results were ugly...