Metrovick F.2
Encyclopedia
The Metropolitan-Vickers F.2 was an early turbojet engine and the first British design to be based on an axial-flow compressor
. It was considered too unreliable for use during the war, and never entered production. The potential of the engine and the investment did not go to waste, however, and eventually resulted in an engine design that was passed on by Metropolitan-Vickers
("Metrovick") when they left the gas turbine business to Armstrong Siddeley
; as the Sapphire.
published a seminal paper in 1926, An Aerodynamic Theory of Turbine Design, that for the first time clearly demonstrated that a gas turbine
could be used as a practical, and even desirable, aircraft powerplant. The paper started by demonstrating that existing axial compressor designs were "flying stalled" due to their use of flat blades, and that dramatic improvements could be made by using airfoil
designs instead, improvements that made a gas turbine practical. It went on to outline a complete compressor and turbine design, using the extra exhaust power to drive a second turbine that would power a propellor. In today's terminology the design was a turboprop
. In order to prove the design, Griffith and several other engineers at the Royal Aircraft Establishment
built a testbed example of the compressor in 1928 known as Anne, the machinery being built for them by Fraser and Chalmers. After Anne's successful testing they planned to follow this up with a complete engine known as Betty.
In 1929 Frank Whittle
's thesis on pure jet engines was published, and sent to Griffith for comment. After pointing out an error in Whittle's mathematics, he went on to deride the entire concept, saying that the centrifugal compressor
he used would be impractical for aircraft use due to its large frontal area, and that the use of the jet exhaust directly for power would be extremely inefficient. Whittle was distraught, but was convinced that he should patent the idea anyway. Five years later a group of investors persuaded him to start work on what would be the first working British jet engine.
Griffith continued development of his own concepts, eventually developing an advanced compressor design using two contra-rotating
stages that improved efficiency. His partner, Hayne Constant
, started discussions in 1937 with Manchester
-based Metrovick, a maker of steam turbine
s, to produce the new machinery. Incidentally, Metrovick had recently merged with British Thomson-Houston
, another turbine builder who were supporting Whittle's efforts.
the next year, and work on Betty, also known as the B.10, started. In 1939 the team, including Metrovick engineers led by David Smith, started work on a flyable design, the F.1. Compared to the centrifugal-flow Whittle designs, the F.1 was extremely advanced, using a nine-stage axial compressor, annular combustion chamber
, and a two-stage turbine (the second driving a propeller).
In April 1939, Whittle gave a startling demonstration of his experimental engine, the WU, running it for 20 minutes at high power. This led to a rash of contracts to build a production quality design suitable for aircraft use. Development had just started on the F.1 when Whittle started building his W.1 design, planning to install one for flight in the Gloster E.28/39
the next year. 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, Freda, in July 1940.
test-bed (the first prototype Lancaster, s/n BT308) on 29 June 1943, mounted in the rear fuselage. Production quality versions were tested on the F.9/40M (Gloster Meteor
) s/n DG204/G which made its first flight on November 13, 1943. These were installed in Messerschmitt Me 262
type underslung nacelles.
As expected, 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). (Around this time, the Whittle W.2B was developing 1,600 lbf (7.11 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.
Mk.II s/n
LL735 before being
installed in the Saunders-Roe SR.A/1
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). In comparison, the Derwent developed 10.9 kN in its ultimate form; making the Beryl one of the most powerful engines of the era. Development of the SR.A/1 ended in 1947, ending development of the Beryl along with it. Nevertheless a Beryl from the SR.A/1 prototype was removed and used by Donald Campbell
in his famous 1955 Bluebird K7
hydroplane in which he set seven water speed records between 1955 and 1964.
fell from 1.05 to 0.65, which was the true aim of the project. Additionally, the team noticed that the cold air from the propellers mixed with the hot exhaust from the engine, resulting in a marked decrease in noise levels, the first time this effect was recorded (it was re-discovered during a major NASA
project in the 1960s).
Although the F.3 progressed nicely, development was curtailed during the war. When the war ended the F.2/2 was no longer a going concern, so the same ideas were applied to the current F.2/4 instead.
. The Sapphire matured into a successful design, initially besting the power of its Rolls-Royce contemporary, the Avon
. Design features of the Metrovick line were worked into Armstrong Siddeley's own line of axial compressor turboprops, although Armstrong Siddeley dropped Metrovick's use of gemstone names for their engines in favour of continuing with animal names in particular snakes.
An example of the prototype engine can be found in the Science Museum
Flight Gallery in London
.
Axial compressor
Axial compressors are rotating, airfoil-based compressors in which the working fluid principally flows parallel to the axis of rotation. This is in contrast with other rotating compressors such as centrifugal, axi-centrifugal and mixed-flow compressors where the air may enter axially but will have...
. It was considered too unreliable for use during the war, and never entered production. The potential of the engine and the investment did not go to waste, however, and eventually resulted in an engine design that was passed on by Metropolitan-Vickers
Metropolitan-Vickers
Metropolitan-Vickers, Metrovick, or Metrovicks, was a British heavy electrical engineering company of the early-to-mid 20th century formerly known as British Westinghouse. Highly diversified, they were particularly well known for their industrial electrical equipment such as generators, steam...
("Metrovick") when they left the gas turbine business to Armstrong Siddeley
Armstrong Siddeley
Armstrong Siddeley was a British engineering group that operated during the first half of the 20th century. It was formed in 1919 and is best known for the production of luxury motor cars and aircraft engines.-Siddeley Autocars:...
; as the Sapphire.
Development
Alan Arnold GriffithAlan Arnold Griffith
Alan Arnold Griffith was an English engineer, who, among many other contributions, is best known for his work on stress and fracture in metals that is now known as metal fatigue, as well as being one of the first to develop a strong theoretical basis for the jet engine.-Early work:A. A...
published a seminal paper in 1926, An Aerodynamic Theory of Turbine Design, that for the first time clearly demonstrated that a gas turbine
Gas turbine
A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between....
could be used as a practical, and even desirable, aircraft powerplant. The paper started by demonstrating that existing axial compressor designs were "flying stalled" due to their use of flat blades, and that dramatic improvements could be made by using airfoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
designs instead, improvements that made a gas turbine practical. It went on to outline a complete compressor and turbine design, using the extra exhaust power to drive a second turbine that would power a propellor. In today's terminology the design was a turboprop
Turboprop
A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
. In order to prove the design, Griffith and several other engineers at the Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
built a testbed example of the compressor in 1928 known as Anne, the machinery being built for them by Fraser and Chalmers. After Anne's successful testing they planned to follow this up with a complete engine known as Betty.
In 1929 Frank Whittle
Frank Whittle
Air Commodore Sir Frank Whittle, OM, KBE, CB, FRS, Hon FRAeS was a British Royal Air Force engineer officer. He is credited with independently inventing the turbojet engine Air Commodore Sir Frank Whittle, OM, KBE, CB, FRS, Hon FRAeS (1 June 1907 – 9 August 1996) was a British Royal Air...
's thesis on pure jet engines was published, and sent to Griffith for comment. After pointing out an error in Whittle's mathematics, he went on to deride the entire concept, saying that the centrifugal compressor
Centrifugal compressor
Centrifugal compressors, sometimes termed radial compressors, are a sub-class of dynamic axisymmetric work-absorbing turbomachinery.The idealized compressive dynamic turbo-machine achieves a pressure rise by adding kinetic energy/velocity to a continuous flow of fluid through the rotor or impeller...
he used would be impractical for aircraft use due to its large frontal area, and that the use of the jet exhaust directly for power would be extremely inefficient. Whittle was distraught, but was convinced that he should patent the idea anyway. Five years later a group of investors persuaded him to start work on what would be the first working British jet engine.
Griffith continued development of his own concepts, eventually developing an advanced compressor design using two contra-rotating
Contra-rotating
Contra-rotating, also referred to as coaxial contra-rotating, is a technique whereby parts of a mechanism rotate in opposite directions about a common axis, usually to minimise the effect of torque. Examples include some aircraft propellers, resulting in the maximum power of a single piston or...
stages that improved efficiency. His partner, Hayne Constant
Hayne Constant
Hayne Constant, C.B., C.B.E., F.R.S, F.R.Ae.S. was an English mechanical and aeronautical engineer who developed jet engines during World War II....
, started discussions in 1937 with Manchester
Manchester
Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...
-based Metrovick, a maker of steam turbine
Steam turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....
s, to produce the new machinery. Incidentally, Metrovick had recently merged with British Thomson-Houston
British Thomson-Houston
British Thomson-Houston was a British engineering and heavy industrial company, based at Rugby, Warwickshire, England. They were known primarily for their electrical systems and steam turbines. They were merged with the similar Metropolitan-Vickers company in 1928, but the two maintained their own...
, another turbine builder who were supporting Whittle's efforts.
F.1
A contract for development work was eventually given by the Air MinistryAir Ministry
The Air Ministry was a department of the British Government with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964...
the next year, and work on Betty, also known as the B.10, started. In 1939 the team, including Metrovick engineers led by David Smith, started work on a flyable design, the F.1. Compared to the centrifugal-flow Whittle designs, the F.1 was extremely advanced, using a nine-stage axial compressor, annular combustion chamber
Combustion chamber
A combustion chamber is the part of an engine in which fuel is burned.-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber...
, and a two-stage turbine (the second driving a propeller).
In April 1939, Whittle gave a startling demonstration of his experimental engine, the WU, running it for 20 minutes at high power. This led to a rash of contracts to build a production quality design suitable for aircraft use. Development had just started on the F.1 when Whittle started building his W.1 design, planning to install one for flight in the Gloster E.28/39
Gloster E.28/39
|-See also:-References:NotesBibliography* James, Derek N. Gloster Aircraft since 1917. London: Putnam, 1987. ISBN 0-85177-807-0.* Mondey, David. The Hamlyn Concise Guide to British Aircraft of World War II. London: Chancellor Press, 1994. ISBN 1-85152-668-4.* Morgan, Eric B. "A New Concept of...
the next year. 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, Freda, in July 1940.
F.2 Freda
Development of the F.2 progressed rapidly, and the engine ran for the first time in November 1941. By this point there were a number of engines in development based on the Whittle concept, but the F.2 looked considerably more capable than any of them. Flyable versions, the F.2/1, received its test rating in 1942 and were flown on an Avro LancasterAvro Lancaster
The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force . It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other...
test-bed (the first prototype Lancaster, s/n BT308) on 29 June 1943, mounted in the rear fuselage. Production quality versions were tested on the F.9/40M (Gloster Meteor
Gloster Meteor
The Gloster Meteor was the first British jet fighter and the Allies' first operational jet. It first flew in 1943 and commenced operations on 27 July 1944 with 616 Squadron of the Royal Air Force...
) s/n DG204/G which made its first flight on November 13, 1943. These were installed in Messerschmitt Me 262
Messerschmitt Me 262
The Messerschmitt Me 262 Schwalbe was the world's first operational jet-powered fighter aircraft. Design work started before World War II began, but engine problems prevented the aircraft from attaining operational status with the Luftwaffe until mid-1944...
type underslung nacelles.
As expected, 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). (Around this time, the Whittle W.2B was developing 1,600 lbf (7.11 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.
F.2/2
To address these problems, in August 1942 a minor redesign delivered the F.2/2, which changed the turbine material from Rex 75 to Nimonic 75, and lengthened the combustion chamber by 6 inches (152.4 mm). Thrust was improved to 2400 lbf (10,675.7 N) static, but the problems with overheating remained.F.2/3
Another attempt to solve the overheating problems resulted in the more highly modified F.2/3 during 1943. This version replaced the original annular combustion chamber with can-type burners like those on the Whittle designs. This appears to have solved the problems, raising the thrust to 2700 lbf (12,010.2 N) in the process. However, by this time it was decided to move on to a much more powerful version of the engine.F.2/4 Beryl
Development of the F.2 continued on a version using a ten-stage compressor for additional airflow. The new F.2/4 - the Beryl - initially developed 3,250 lbf (14.45 kN) and was test flown in Avro LancasterAvro Lancaster
The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force . It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other...
Mk.II s/n
United Kingdom military aircraft serials
In the United Kingdom to identify individual aircraft, all military aircraft are allocated and display a unique serial number. A unified serial number system, maintained by the Air Ministry , and its successor the Ministry of Defence , is used for aircraft operated by the Royal Air Force , Fleet...
LL735 before being
installed in the Saunders-Roe SR.A/1
Saunders-Roe SR.A/1
|-See also:-References:*London, Peter. British Flying Boats. Stroud, UK:Sutton Publishing, 2003. ISBN 0-7509-2695-3.*Mason, Francis K.The British Fighter since 1912. Annapolis, Maryland, USA:Naval Institute Press, 1992. ISBN 1-55750-082-7....
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). In comparison, the Derwent developed 10.9 kN in its ultimate form; making the Beryl one of the most powerful engines of the era. Development of the SR.A/1 ended in 1947, ending development of the Beryl along with it. Nevertheless a Beryl from the SR.A/1 prototype was removed and used by Donald Campbell
Donald Campbell
Donald Malcolm Campbell, CBE was a British speed record breaker who broke eight world speed records in the 1950s and 1960s...
in his famous 1955 Bluebird K7
Bluebird K7
Bluebird K7 was a turbo jet-engined hydroplane with which the United Kingdom's Donald Campbell set seven world water speed records during the 1950s and 1960s. Campbell lost his life in K7 on January 4, 1967 whilst making a bid to raise the speed record to over on Coniston Water.-Design:Donald...
hydroplane in which he set seven water speed records between 1955 and 1964.
F.3
In 1942 MV started work on thrust augmentation, or what would today be called a turboprop or ultra-high bypass turbofan. Using a stock F.2/2, they added a section to the rear of the engine that contained four contra-rotating turbines attached to two contra-rotating propellers. The project was generally successful, raising thrust from 2400 lbf (10,675.7 N) to 4000 lbf (17.8 kN) for a relatively small increase in weight. More importantly, specific fuel consumptionSpecific fuel consumption
Thrust specific fuel consumption or sometimes simply specific fuel consumption, SFC, is an engineering term that is used to describe the fuel efficiency of an engine design with respect to thrust output...
fell from 1.05 to 0.65, which was the true aim of the project. Additionally, the team noticed that the cold air from the propellers mixed with the hot exhaust from the engine, resulting in a marked decrease in noise levels, the first time this effect was recorded (it was re-discovered during a major NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
project in the 1960s).
Although the F.3 progressed nicely, development was curtailed during the war. When the war ended the F.2/2 was no longer a going concern, so the same ideas were applied to the current F.2/4 instead.
F.5
Following on where the F.3 left off, the F.5 was a version of the F.2/4 with a thrust augmenter added. Thrust for this version was 4710 lbf (20,951.1 N), although it weighed 100 lb (45.4 kg) less than the F.3. The company cancelled development when they sold their gas turbine business to Armstrong Siddeley in 1946.F.9 Sapphire
Development of the F.2 ended in 1944. Development of the basic concept continued, however, eventually leading to the considerably larger F.9 Sapphire. However, in 1947, Metrovick left jet engine production - encouraged or forced by the Air Ministry5. - and their design team moved to Armstrong SiddeleyArmstrong Siddeley
Armstrong Siddeley was a British engineering group that operated during the first half of the 20th century. It was formed in 1919 and is best known for the production of luxury motor cars and aircraft engines.-Siddeley Autocars:...
. The Sapphire matured into a successful design, initially besting the power of its Rolls-Royce contemporary, the Avon
Rolls-Royce Avon
|-See also:-Bibliography:* Gunston, Bill. World Encyclopaedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9-External links:**** a 1955 Flight article on the development of the Avon...
. Design features of the Metrovick line were worked into Armstrong Siddeley's own line of axial compressor turboprops, although Armstrong Siddeley dropped Metrovick's use of gemstone names for their engines in favour of continuing with animal names in particular snakes.
An example of the prototype engine can be found in the Science Museum
Science Museum (London)
The Science Museum is one of the three major museums on Exhibition Road, South Kensington, London in the Royal Borough of Kensington and Chelsea. It is part of the National Museum of Science and Industry. The museum is a major London tourist attraction....
Flight Gallery in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
.