Henschel's plane came in 12 percent overweight with the engines 8 percent underpowered, and understandably, it flew poorly. The controls proved to be almost inoperable as speed increased, and in testing, the V2 prototype flew into the ground from a short dive on 5 January 1940 because the stick forces were too high for the pilot to pull out. The Focke-Wulf design proved to be no better. Both planes were underpowered with their air-cooled, inverted-V12 Argus As 410 engines, and very difficult to fly.