WEBA diagram showing the lift forces on a Yak-38 in VTOL mode A close up view of the air intakes for the smaller VTOL engines. Designed by the A.S. Yakovlev Design Bureau, the first drawings showed a supersonic aircraft strongly resembling the Hawker P.1154 in study in the United Kingdom, but with two R27-300 engines.Supersonic performance would have implied many difficulties of development, and ...