What event was the plane that was powered by the WS-15 engine revealed at?
Xian WS-15 The WS-15 (), codename Emei, is a Chinese afterburning turbofan engine designed by the Shenyang Aeroengine Research Institute and manufactured by the Xi'an Aero-Engine Corporation, used to power China's Chengdu J-20 fighter, which would be able to achieve supercruise.
Boeing Y1B-20 The Boeing Y1B-20 (Boeing 316) was designed as an improvement on the Boeing XB-15 ("Y1-" indicates a funding source outside normal fiscal year procurement.) It was slightly larger than its predecessor, and was intended to use much more powerful engines. It was presented to the Army in early 1938, and two orders were placed soon after. The order was reversed before construction began.