Possibly a new feature for the Typhoon mk IB? Seems that pilots had a radiator vent they would use effectively as an air brake....assign it to shift C?
From combat report of Norman Lucas RAF 266 Squadron (operation Rodeo 78, 9th of Feb, 1944)
"when about 1500yds behind e/a i recognised it as a Do.24 flying boat, so I put my rad shutter down and throttled right back. I opened fire with a 3 second burst from 500yds and closing to 200 from dead astern and slightly below. I saw strikes all over e/a with both outer engines on fire........"
