The RB.108 was the first direct-lift turbojet produced by Rolls-Royce. It originated from a VTOL concept in which Alan A. Griffith proposed using a small number of specialised lift engines in a VTOL aircraft, separate from the engines which provided forward propulsion.
The RB.108 was the initial direct-lift turbojet manufactured by Rolls-Royce. This engine came from a VTOL concept put forth by Alan A. Griffith, which involved using a few specialized lift engines in a VTOL aircraft that were separate from those providing forward propulsion.