4Blues
By the fact that the poster you are referring is titled Grob Queen and refers to High Key I am guessing she (or perhaps he

) is flying with a RAF VGS unit in a Vigilant motor gilder.......and i think they have carb heat applied throughout as SOP.
Am I right GQ?
Hmm then again, vigilants don't have a mixture control so i am probably wide of the mark?
Moli
Edited to add having wracked my brains, Mil Grobs do have carb heat and it is applied at all times other than when at full power. I believe that some civil Grobs don't have carb heat.