Stona see post #6 "test center at Bricy 1939-1940" At that place the French tested the captured German airplanes. Some of them namely the Bf109E3 and Bf109E4, were eventually flown to England and tested further there. But that leaved the Bf109D. That is to me a mystery and as i said i never seen a picture of it. Nor has LEMB any data on this bird that i can find.