His first such design to fly was the Junkers Ju 287, on 16 August 1944. Flight tests on this and later variants confirmed the low-speed advantages but also soon revealed the expected problems, preventing high-speed trials. Wocke and the incomplete Ju 287 V3 prototype were captured and, in 1946, taken to Moscow where the aircraft was completed and flown the next year as the OKB-1 EF 131. The later OKB-1 EF 140 was essentially the same airframe re-engined with a pair of Mikulin-design Soviet jet engines of greater thrust.