The VAK 191B was originally designed to be a low altitude nuclear strike fighter for NATO. The project was funded by both Germany and Italy (on a 60/40 basis) with VFW and Fiat Aviazione the primary airframe companies and Rolls-Royce/MTU responsible for the engines.

The aircraft used two Rolls-Royce/MTU RB.162-81 lift engines (6,000 lb thrust each), one mounted directly behind the cockpit and one aft of the wing, plus a MTU/Rolls-Royce RB.193-12 vectored thrust turbofan engine (10,163 lb thrust) mounted between them. The RB.193 was a scaled down version of the Roll Royce Pegasus engine used on the Kestrel/Harrier.

The program was canceled due to a change in NATO strategy.

Source: "VFW VAK 191B", AHS V/STOL Wheel

and,

Source: "Italian V/STOL Concepts of the Twentieth Century", Michael J. Hirschberg; Thomas Müller and Erasmo Piñero, Presented  at  the  American  Helicopter Society 59th Annual  Forum, Phoenix, Arizona, May  6-8, 2003