Did any VTOL aircraft implement an airfoil with engine-blown exhaust?
Near as I know every attempt to do so has never worked out.   It’s a very enticing design on paper but has always been a disappointment in real life. One of the best examples was from the 1970s. Designed as a supersonic replacements for the AV-8A Harrier, the Rockwell XFV-12A attempted to use this scheme for a vertical lift system.   Unfortunately it never met the design metrics, and the program was ultimately canceled.


Source: boxartden.com