| Proteus | |
|---|---|
| Preserved Bristol Proteus | |
| Type | Turboprop |
| Manufacturer | Bristol Siddeley |
| First run | 25 January 1947 |
| Major applications | Bristol Britannia |
The Bristol Proteus was the Bristol Aeroplane Company's first successful gas-turbine engine design, a turboprop that delivered just over 4,000 hp (3,000 kW). The Proteus was a two spool, reverse flow gas turbine, similar to the original Whittle engine designs with an extra turbine stage. Because the turbine stages of the inner spool drove no compressor stages, but only the propeller, this engine is sometimes classified as a free turbine. It was used mostly on the Bristol Britannia airliner, but saw some third party use as well.
Contents |
Design work on the Proteus started in September 1944, during the course of development the gas generator section was built as a small turbojet which became known as the Bristol Phoebus. This engine was test flown in May 1946 fitted to the bomb bay of an Avro Lincoln, performance was poor due to airflow problems. The centrifugal compressor was redesigned but similar problems were encountered when the Proteus started ground testing on 25 January 1947.[1]
The original Proteus Mk.600 delivered 3,780 hp (2,820 kW), and was going to be used on the early versions of the Britannia and the Saunders-Roe Princess flying-boat. The versions on the Princess were mounted in a large frame driving a single propeller through a gearbox, and were known as the Coupled Proteus. The Coupled Proteus was also intended to be used on the Mk.II versions of the Bristol Brabazon, but this project was cancelled. Only three Princesses were built, only one of which flew, and by the time the Britannia was ready for testing the manufacturer had decided to equip it with the later Mk.700 Proteus instead.
During development, there were severe problems with compressor blades, turbine blades and bearings failing at even low power output levels. This led to the famous quote of Proteus Chief Engineer Frank Owner to Chief Engineer of the Engine Division Stanley Hooker: "You know, Stanley, when we designed the Proteus I decided we should make the engine with the lowest fuel consumption in the world, regardless of its weight and bulk. So far, we have achieved the weight and bulk!"[2]
At this point the Proteus proved to have troubling icing problems, causing the engine and aircraft projects to be delayed while solutions were found. The Mk.705 of 3,900 hp (2,900 kW) was the first version to see widespread production on the Bristol Britannia 100 and some 300 series. The Mk.755 of 4,120 hp (3,070 kW) was used on the 200 series (not built) and other 300's, and the Mk.765 of 4,445 hp (3,315 kW) was used on the RAF's Series 250 aircraft.
After testing on the frigate HMS Exmouth a marinised Proteus engine was used to power the Royal Navy's Brave class fast patrol boats, and subsequently in many FPBs of similar design built for export by Vosper. These were among the fastest warships ever built, achieving over 50 knots on flat water.
The Proteus was used on the SR.N4 Mountbatten class cross-channel hovercraft. In this installation four "Marine Proteus" engines were clustered in the rear of the craft, exhausts pointed rearward. The engines drove horizontal power shafts that delivered power to one of four "pylons" positioned at the corners of the boat. At the pylons, gearboxes used the horizontal torque to power a vertical shaft, with a lift fan at the bottom and propeller at the top. The two at the front required long shafts that ran over the passenger cabin.[3]
A unique variant of the engine was also used to power the four-wheel drive Bluebird-Proteus CN7, Donald Campbell's land speed record car. This had a drive shaft at each end of the engine, each to a separate axle.
For many years, a Proteus engine was used at the Rolls-Royce_plc test site at Hucknall in a "Cross-Wind Blower". This could simulate winds of up to 40 knots, and was used to demonstrate the stability of gas turbine engines under extreme conditions.
Another use of the Proteus was for remote power generation in the South West of England in what were called "Pocket Power Stations".[4][5] The regional electricity board installed several 2.7MW remote operated generation sets for peak load powered by the Proteus. Designed to run for ten years many were still in use forty years later.[6]
Data from Flight[7]
|
|||||||||||
|
||||||||||||||