Sapphire | |
---|---|
Preserved Armstrong Siddeley Sapphire at the Midland Air Museum | |
Type | Turbojet |
Manufacturer | Armstrong Siddeley |
First run | 1 October 1948 |
Major applications | Gloster Javelin Handley Page Victor Hawker Hunter |
Variants | Wright J65 |
The Armstrong Siddeley Sapphire is a British turbojet engine that was produced by Armstrong Siddeley in the 1950s. It was the ultimate development of work that had started as the Metrovick F.2 in 1940, evolving into an advanced axial flow design with an annular combustion chamber that developed over 11,000 lbf (49 kN). It powered early versions of the Hawker Hunter and Handley Page Victor, and every Gloster Javelin. Production was also started under licence in the United States by Wright Aeronautical as the J65 , powering a number of US designs. The Sapphire's primary competitor was the Rolls-Royce Avon.
Design evolution of the Sapphire started at Metropolitan-Vickers (Metrovick) in 1943 as an offshoot of the F.2 project. With the F.2 reaching flight quality at about 1,600 lbf (7,100 N), Metrovick turned to producing larger designs, both an enlarged F.2 known as the Beryl, as well as the much larger F.9 Sapphire. (The names were chosen after a decision to use gemstones for future engine names). The Beryl eventually developed 4,000 lbf (18 kN) thrust, but the only project to select it, the Saunders-Roe SR.A/1, was cancelled. The Ministry of Supply (MoS) designated the F.9 as the MVSa.1.
In 1948 [1] Metrovick exited the jet engine industry. [2] [3] Armstrong Siddeley, who already had a turbine development of their own, the ASX, took over the MVSa.1, now renamed ASSa.1.
After a redesign it emerged as the ASSa.2. In December 1949 the ASSa.2 completed an acceptance test at 7,380 lbf (32,800 N). Its competitor, the Avon RA.3 had a design thrust of 6,500 lbf (29,000 N) at that time. [4] A number of companies expressed interest in the Sapphire, and it was considered as either the main or backup powerplant for most British designs of the late '40s and early '50s.
The ASSa.5 with 7,500 lbf (33,000 N) thrust was used only on the English Electric P.1A, prototype for the Lightning. A simple fixed-nozzle reheat was fitted to extend the performance boundary for stability and control testing from about Mach 1.1 to beyond Mach 1.5. [5] Future versions of the Lightning were powered by the Avon.
The ASSa.6, 8,300 lbf (37,000 N), was used on the Gloster Javelin FAW Mk.1, Hawker Hunter F.Mk.2 and F.Mk.5, and the prototype Sud Ouest SO 4050 Vautour. The higher thrust ASSa.7 at 11,000 lbf (49 kN) was the first British engine to be rated above 10,000 lbf (44 kN) and it powered the Gloster Javelin FAW Mk.7, Handley Page Victor B.Mk.1 and a prototype Swiss fighter-bomber, the FFA P-16.
The Sapphire compressor operated well, free from surging, [6] over its complete RPM range without the need for variable inlet guide vanes (VIGV) or bleed. However, early compressor stages suffered from fatigue due to rotating stall at low RPM and various fixes, such as lacing wire, were incorporated. Curtiss-Wright introduced variable ramps on the Wright J65 at the entry to the compressor [7] to prevent the stalling and blade excitation. Armstrong-Siddeley tested a similar solution on the Sapphire but incorporated blade changes instead to reduce the blade response to the stalling. [8]
Caygill [9] states that one of the most serious problems encountered throughout the life of the Gloster Javelin was caused by "centre-line closure" on the Sapphire engine. Flying through thick cloud could cause the compressor case to shrink and rub the blades causing catastrophic engine failures and loss of the aircraft. "Centre-line closure" also caused a Sapphire failure on a Victor B.1. [10]
An afterburner with limited boost was required for the Javelin's ASSa.7, making it the ASSa.7LR. 12% boost was required at high altitudes to regain the bomber intercept performance that had been lost carrying the new de Havilland Firestreak missiles. [9] Afterburners with a low boost requirement were sometimes known as "wee-heat". [9] Other low-boost reheats have included the "tailpipe augmentation"(TPA) on the F-86H (J73) with +10% at take-off [11] and "Bristol Simplified Reheat"(BSR), with about 16% boost at take-off, tested on Derwent V, Orenda, Olympus [12] and Orpheus engines. [13]
An Armstrong Siddeley Sapphire is on static display at the Midland Air Museum, Coventry Airport, Warwickshire.
Very few Armstrong Siddeley Sapphire engines exist, other known examples are preserved at the Jet Age Museum in Gloucester, England, and the Malta Aviation Museum at Ta' Qali.
Data fromJane's. [15]
Related development
Comparable engines
Related lists
An afterburner is an additional combustion component used on some jet engines, mostly those on military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, takeoff, and combat. The afterburning process injects additional fuel into a combustor in the jet pipe behind the turbine, "reheating" the exhaust gas. Afterburning significantly increases thrust as an alternative to using a bigger engine with its attendant weight penalty, but at the cost of increased fuel consumption which limits its use to short periods. This aircraft application of "reheat" contrasts with the meaning and implementation of "reheat" applicable to gas turbines driving electrical generators and which reduces fuel consumption.
The Gloster Javelin is a twin-engined all-weather interceptor aircraft that served with Britain's Royal Air Force from the mid-1950s until the late 1960s. It was a T-tailed delta-wing aircraft designed for night and all-weather operations and was the last aircraft design to bear the Gloster name. Introduced in 1956 after a lengthy development period, the aircraft received several upgrades during production to its engines, radar and weapons, including support for the De Havilland Firestreak air-to-air missile.
The Rolls-Royce Pegasus is a British turbofan engine originally designed by Bristol Siddeley. It was manufactured by Rolls-Royce plc. The engine is not only able to power a jet aircraft forward, but also to direct thrust downwards via swivelling nozzles. Lightly loaded aircraft equipped with this engine can manoeuvre like a helicopter. In particular, they can perform vertical takeoffs and landings. In US service, the engine is designated F402.
The Rolls-Royce Olympus was the world's second two-spool axial-flow turbojet aircraft engine design, first run in May 1950 and preceded only by the Pratt & Whitney J57, first-run in January 1950. It is best known as the powerplant of the Avro Vulcan and later models in the Concorde SST.
The Rolls-Royce RB.53 Dart is a turboprop engine designed and manufactured by Rolls-Royce Limited. First run in 1946, it powered the Vickers Viscount on its maiden flight in 1948. A flight on July 29 of that year, which carried 14 paying passengers between Northolt and Paris–Le Bourget Airport in a Dart-powered Viscount, was the first regularly scheduled airline flight by a turbine-powered aircraft. The Viscount was the first turboprop-powered aircraft to enter airline service - British European Airways (BEA) in 1953.
The Rolls-Royce Avon was the first axial flow jet engine designed and produced by Rolls-Royce. Introduced in 1950, the engine went on to become one of their most successful post-World War II engine designs. It was used in a wide variety of aircraft, both military and civilian, as well as versions for stationary and maritime power.
The Rolls-Royce RB.23 Welland was Britain's first production jet engine. It entered production in 1943 for the Gloster Meteor. The name Welland is taken from the River Welland, in keeping with the Rolls-Royce policy of naming early jet engines after rivers based on the idea of continuous flow, air through the engine and water in a river.
This article outlines the important developments in the history of the development of the air-breathing (duct) jet engine. Although the most common type, the gas turbine powered jet engine, was certainly a 20th-century invention, many of the needed advances in theory and technology leading to this invention were made well before this time.
The Metropolitan-Vickers F.2 is an early turbojet engine and the first British design to be based on an axial-flow compressor. It was an extremely advanced design for the era, using a nine-stage axial compressor, annular combustor, and a two-stage turbine.
The Snecma Atar is a French axial-flow turbojet engine built by Snecma. It was derived from the German World War II BMW 018 design, and developed by ex-BMW engineers through a progression of more powerful models. The name is derived from its original design group, Atelier technique aéronautique de Rickenbach near Lindau within the French Occupation Zone of Germany. The Atar powered many of the French post-war jet aircraft, including the Vautour, Étendard and Super Étendard, Super Mystère and several models of the Mirage.
The Wright J65 was an axial-flow turbojet engine produced by Curtiss-Wright under license from Armstrong Siddeley. A development of the Sapphire, the J65 powered a number of US designs.
The Armstrong Siddeley Viper is a British turbojet engine developed and produced by Armstrong Siddeley and then by its successor companies Bristol Siddeley and Rolls-Royce Limited. It entered service in 1953 and remained in use with the Royal Air Force, powering its Dominie T1 navigation training aircraft until January 2011.
The Armstrong Siddeley ASX was an early axial flow jet engine built by Armstrong Siddeley that first ran in April 1943. Only a single prototype was constructed, and it was never put into production. A turboprop version as the ASP was somewhat more successful, and as the Armstrong Siddeley Python saw use in the Westland Wyvern.
The Bristol Siddeley Orpheus is a single-spool turbojet developed by Bristol Siddeley for various light fighter/trainer applications such as the Folland Gnat and the Fiat G.91. Later, the Orpheus formed the core of the first Bristol Pegasus vectored thrust turbofan used in the Harrier family.
The de Havilland Gyron Junior is a military turbojet engine design of the 1950s developed by the de Havilland Engine Company and later produced by Bristol Siddeley. The Gyron Junior was a scaled-down derivative of the de Havilland Gyron.
The Rolls-Royce/Snecma Olympus 593 was an Anglo-French turbojet with reheat, which powered the supersonic airliner Concorde. It was initially a joint project between Bristol Siddeley Engines Limited (BSEL) and Snecma, derived from the Bristol Siddeley Olympus 22R engine. Rolls-Royce Limited acquired BSEL in 1966 during development of the engine, making BSEL the Bristol Engine Division of Rolls-Royce.
The General Electric J73 turbojet was developed by General Electric from the earlier J47 engine. Its original USAF designation was J47-21, but with innovative features including variable inlet guide vanes, double-shell combustor case, and 50% greater airflow was redesignated J73. Its only operational use was in the North American F-86H.
The Ishikawajima-Harima J3 was a Japanese turbojet aircraft engine. It was the first jet engine designed and built in Japan after the Second World War and was used to power the Fuji T-1 trainer and as a booster engine in the Kawasaki P-2J patrol aircraft.
The Rolls-Royce Olympus turbojet engine was developed extensively throughout its production run, the many variants can be described as belonging to four main groups.
The thin-wing Javelin refers to a series of design studies for an improved supersonic-capable version of the Gloster Javelin aircraft. Depending on the source, it is also known as F.153D, after its Air Ministry issued Operational Requirement, or the Super Javelin in some Gloster documents.