Metropolitan-Vickers: F2/4 Jet Engine
Note this is a sub-section of Metropolitan-Vickers: Jet Engines
Dr A. A. Griffith, working on gas turbines at the Royal Aircraft Establishment, developed an advanced compressor design using two contra-rotating stages that improved efficiency.
1937 Hayne Constant, Griffith's colleague, started discussions with Metropolitan-Vickers, a maker of steam turbines, to produce the new machinery.
1938 The Air Ministry gave Metrovicks a contract for development work on the engine, called B.10. This was not envisaged as a jet engine.
1939 The team, including Metrovick engineers led by David Smith, started work on a flyable design, the F.1. This was a very advanced design, using a nine-stage axial compressor, annular combustion chamber, and a two-stage turbine (the second driving a propeller).
1939 After Whittle's demonstration of his engine, Smith decided to end development of the F.1 and move on to a pure-jet instead, starting work on the otherwise similar F.2 in July 1940.
1940 the Ministry of Aircraft Production asked Metropolitan-Vickers to undertake the development of an axial-flow jet engine. The outcome was the now famous F2 type in which the gases flowed straight through an axial flow compressor, an annular combustion chamber, a turbine and an exhaust cone.
1941 Bench tests began in December.
1942 A flyable version, the F.2/1, received its test rating in 1942 and were flown on an Avro Lancaster test-bed on 29 June 1943, mounted in the rear fuselage.
1943 On November 13, 1943, a prototype Gloster Meteor fighter equipped with F2 engines made a flight from Farnborough. These were installed in underslung nacelles. This was the first time that a jet propelled aircraft with axial-flow engines had been flown in the UK.
The engines were more powerful than the Whittle design, first delivering 1,800 lbf (8 kN) but soon scaling up to well over 2,000 lbf (8.9 kN). However, the engine suffered from a number of problems that cast doubts on its reliability. These were primarily due to hot spots building up on the turbine bearing and combustion chamber. The latter, in turn, caused warping and fractures of the turbine inlet nozzles.
Eventually the overheating problem was resolved in the F.2/3 during 1943 by replacing the original annular combustion chamber with can-type burners like those on the Whittle designs. Thrust was raised to 2,700 lbf (12,000 N) in the process.
Development of the F.2 continued on a version using a ten-stage compressor for additional airflow driven by a single stage turbine. The new F.2/4 initially developed 3,250 lbf (14.45 kN) and was test flown in Avro Lancaster before being installed in the Saunders-Roe: SR/A1 flying boat fighter. Thrust had already improved to 3,850 lbf (17.1 kN) for the third prototype, and eventually settled at 4,000 lbf (17.8 kN), making the engine one of the most powerful of its era. The production engine was known as the Beryl.
1944 Development of the F.2 ended but development of the concept continued, eventually leading to the considerably larger F.9 Sapphire.
1947 Metrovick sold its jet engine unit to Armstrong Siddeley Motors, and the design team moved there. The Sapphire matured into a successful design, initially beating the power of its Rolls-Royce contemporary, the Avon. Design features of the Metrovick line were incorporated in Armstrong Siddeley's own line of axial compressor turboprops.
Development of the SR.A/1 ended in 1947, ending development of the Beryl with it. Nevertheless a Beryl from the SR.A/1 prototype was removed and used by Donald Campbell for early runs in his famous 1955 Bluebird K7 hydroplane in which he set seven water speed records between 1955 and 1964.
See Also
Sources of Information
- All-aero.com [1]