The Rolls-Royce RB.108 was a British

jet engine A jet engine is a type of reaction engine discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include rocket, Pump-jet, water jet, and hybrid propulsion, the term ...

designed in the mid-1950s by

Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...

specifically for use as a

VTOL A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...

lift engine. It was also used to provide horizontal thrust in the

Short SC.1 The Short SC.1 was the first British fixed-wing vertical take-off and landing (VTOL) jet aircraft. It was developed by Short Brothers. It was powered by an arrangement of five Rolls-Royce RB.108 turbojets, four of which were used for vertical ...

Design and development

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. Its power output (thrust) was not high enough for use as a practical engine in a production aircraft and was used only for research into VTOL. It was constructed from conventional materials. (The next engine, the RB.162, would have a compressor built mainly from glass-fibre composite and have a higher T/W ratio.) The RB.108 bearings and

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...

system were designed to operate with an engine attitude envelope which covered engine and aircraft tilting while transitioning between hovering and forward flight. When a fifth engine was installed in the SC.1 to provide forward thrust it had to be mounted at about 45 degrees to remain within the envelope. The exhaust was directed horizontally with a curved jetpipe.

Operational history

The RB.108 was used in the

, which used four for lift with an additional one mounted at an angle at the rear for propulsion, and the

Dassault Balzac V The Dassault Balzac V was a French vertical takeoff and landing (VTOL) testbed of the early 1960s. It was built by Dassault Aviation from a prototype Mirage III aircraft to test the configuration for the Mirage IIIV. The sole example was badly ...

, which used eight vertically mounted RB.108s for lift. The

Vereinigte Flugtechnische Werke Vereinigte Flugtechnische Werke (VFW) was a West German aerospace manufacturer. The company was formed by the 1964 merger of two German aerospace firms, Focke-Wulf and Weser Flugzeugbau GmbH (Weserflug). The formation of VFW was a natural outco ...

(VFW) SG 1262 used five RB.108s, three mounted in tandem on the centreline, with one RB.108 either side. The RB.108 was also the intended powerplant for several other VTOL aircraft designs, including one by Dornier. A similar lift jet was designed by

Bristol Siddeley Bristol Siddeley Engines Ltd (BSEL) was a British aero engine manufacturer. The company was formed in 1959 by a merger of Bristol Aero-Engines Limited and Armstrong Siddeley Motors Limited. In 1961 the company was expanded by the purchase of t ...

, the BS.59, with a thrust of 8,000 lb the engine was intended for the projected

Focke-Wulf Fw 260 The Focke-Wulf Fw 260 Flamingo and Focke-Wulf Fw 300 were a pair of related VTOL airliner projects, designed by Focke-Wulf during the early 1960s. Neither aircraft was built. Fw 260 The Fw 260 design was displayed at the Luftfahrtschau Hanover ...

Applications

VFW SG 1262 Schwebegestell The German VFW SG 1262 ''Schwebegestell'' (hover rig) was designed and built in 1965 by Vereinigte Flugtechnische Werke (VFW) as an experimental aircraft to assist with the development of several vertical takeoff and landing (VTOL) military a ...

Specifications (RB.108)

References

Notes

Bibliography

* Gunston, Bill. ''World Encyclopedia of Aero Engines''. Cambridge, England. Patrick Stephens Limited, 1989.

External links

A photograph of an RB.108
{{Rolls-Royce aeroengines RB.108 1950s turbojet engines Lift jet