Gertrude ..... i'm not sure what you were flying, but you were sensible to take instruction, but I would say you can achieve more that the exra 200 feet per minute. But the instructor was probably and rightly so, being a bit conservate. Obviviously the ROD is going to vary between types, what it says in the Flight Manual, how much bank is used and the rudder authority.
I beleive that is one of the reasons, some maufaturers, advise against sideslipping with full flap also, if you look at the rudders at the early Slingby T67 is much smaller than say the Bulldog or Beagle Pup.
As a word of warning, there was a number of years ago, gliding club usiing DHC Chipmonks and pushed the aircraft to the limits in terms of sidesliping, it was an accident waiting to happen. During a check flight, on finals the aircraft flight rolled inverted, landed inverted killing the pilots.
I'm not entirely what caused the aircraft to flick but I suspect the aircraft was still in a turn the pilot intiated a high ROD using sidesl. Alternately he may have applied full flap while in still in slideslip, but I think that less likely.
Last edited by Homsap; 13th Aug 2017 at 12:40.