Reply to Nearly There - deep stall
Correct, in that there is zero downdraught at zero airspeed. But "deep stall" happens before that point. The deflection is enough when the aircraft is stalling and the tail is in the wake of where the turbulence would be (if the aircraft were to only have the lower wing) to avoid the tail and retain some authority. If the airspeed is zero, then the T Tail will have no effect regardless of the configuration.
Technically our aircraft does not go into deep stall because the angle is so steep and the speed so slow when it happens we don't actually enter the shadow of the wing. However, the correct way to actually describe it in writing is somewhat difficult.
Thanks for the enquiry since it is always a pleasure to talk about tangibles.
Mike Dutton
Brigante Aviation (Trinidad and Tobago)