The Engineering Behind That 606-Mph Meteor

by A H Narracott,
Air Correspondent, London Times

Traveling at almost 900 ft per second. the Gloster Meteor recently bettered previous speed records by over 135 mph. Disclosed here is history of research and development of the craft and of the Rolls-Royce Derwent V jet engines which power it.

The world airspeed record of 469.2 mph, established in Germany in 1939, was broken on November 7 at Herne Bay, England, by Group Capt H J Wilson, AFC, of the RAF, flying a Gloster Meteor IV jet-propelled aircraft, powered by two Rolls-Royce Derwent V engines. He established a new speed mark by covering four laps over a 3-km course with an average speed of 606 mph. His lap times were 604, 608, 602, and 611 mph.

The craft, selected for Britain’s attack on the speed standard, and the Rolls-Royce Derwent jet-propulsion engines with which it is powered, are respectively the indirect and direct outcome of the pioneering efforts of Air Commodore Frank Whittle, RAF, who designed and developed the first jet unit in Britain, even though the Derwent engine represents a great advance on the original Whittle unit.

Starting as early as 1928, Whittle obtained sufficient backing to form the firm of Power Jets, Ltd, since taken over by the British Government. First design was a single-combustion-chamber type, with single-stage turbine-operated compressor. Compression ratio aimed at was 4:1 using a 16-1/2 dia turbine wheel to operate compressor supplying 3,000 shp.

Testing of the first Whittle engine began in Apr 1937, but various defects were discovered. Later, in Oct 1938, the third type was damaged beyond repair by a turbine failure, but not before it had yielded information to enable the development work to proceed.

Flight testing started in 1939, and in the Summer the British Air Ministry placed a contract with the Gloster Aircraft Co for the manufacture of an experimental aircraft which became known by its specification number of E28/39 and was the prototype of the Gloster Meteor twin-jet fighter.

The engines were installed in the E28/39 airframe for taxiing trials in Apr, 1941, and flight trials started the following month. In the first few efforts, the machine exceeded the then top speed of the Spitfire at all heights. Initially powered by the W-1 engine, which was rated at a static thrust of only 850 lb, the E28/39 was flown subsequently with a succession of engines supplied by Power Jets and Rolls-Royce, and it achieved a speed approaching 500 mph before being grounded.

By arrangement between the British and United States Governments, one Whittle-type engine, built by British Thomson-Houston, a complete set of drawings, and a small team of Power Jets engineers, were flown to America in the Fall of 1941 and thus initiated the intensive development of the jet-propulsion gas turbine by General Electric at Lynn, MA. What was known as the W2B engine became the prototype of the Rolls-Royce Welland engine which subsequently powered the Meteor Mark I in Britain. Type 1, the engine made by General Electric in America, powered the Bell P-59 Airacomet. The Meteor I went into production with the Welland engine and was delivered to RAF Fighter Command squadrons in time to take a heavy toll of the V-1 flying bombs directed against Southeastern England from German bases on the continent.

It may be noted that although an RAF squadron equipped with Meteors was stationed in Holland during the closing stages of the war and made almost daily patrols, these flyers did not succeed in making contact with the jet-propelled Messerschmitt 262.

Meanwhile, development of the jet engine went steadily ahead at the Rolls-Royce works in England, and the Derwent engine was produced. It now develops twice the power of its predecessor, the Welland, and in order to accommodate this engine, the nacelles of the Meteor have been made longer.

The Meteor is a single-seat fighter, a low-wing all-metal monoplane with a tricycle landing gear. Wing span is 43 ft, length 41 ft, height 13 ft, and wing area 374 sq ft. The aircraft is constructed of six separate units: The fuselage nose; front fuselage with nose wheel ; center section (embodying the center plane with the two undercarriage units and the two nacelles); two outer planes, with ailerons; and the rear fuselage, complete with tail portion and tail unit, consisting of the upper fin, upper and lower rudders, stabilizer, and elevators. The high stabilizer, necessitated by the jets from the propelling nozzles, splits the rudder in two. Trimming tabs are fitted on each elevator and to the lower portion of the rudder.

Front fuselage basis comprises two fore-and-aft vertical diaphragms and three solid bulkheads. The internal structure is sealed between the nose wheel bulkhead and the seat bulkhead to form a pressure cabin if required. The third, or front spar bulkhead, is bolted to a similar bulkhead in the center section. The center section and the rear fuselage are semimonocoque.

Two rearmost frames of the rear fuselage are extended upward to form posts for the lower fin and to give attachment points for the stabilizer and upper fin. Main wing is a two-spar stressed-skin structure. Center section spars are spaced by six major ribs interspaced with lighter skin ribs. Each engine nacelle has two main frames attached near the outer ends of the spars. The two undercarriage bays, upper and lower air brakes, and flaps are all between the nacelles and the center fuselage. The outer wings, joined to center section of both spars, have plate and lattice type ribs. Internally mass-balanced ailerons are all-metal structures with tabs. The outer wing tip is detachable, for production and replacement reasons. Components of the tail unit are of stressed-skin construction.

Hydraulically operated tricycle landing gear consists of two independent units retracting inboard and a nose wheel which retracts rearward, the wheel being housed between the rudder pedals.

Control stick has a hinged spade grip, and rudder pedals have parallel action. Trim tabs are operated by hand wheels. Each engine is mounted between two center section ribs. The same type wide trunnion mountings are used for the Derwent or Welland engines, but the Wellands have a forward steadying attachment while the Derwent engines are steadied at the rear by a torsionally free diamond bracing. The generator (port nacelle), hydraulic pump (starboard nacelle), and vacuum pumps (both nacelles) are driven by gearboxes on the front spar in front of the engines.

The self-sealing fuel tank is divided by a transverse diaphragm; each compartment normally feeds one engine, but there is an interconnecting balance cock, normally closed. Feed to the burners is maintained by tank-mounted and engine-driven pumps. The oil system for each engine is self-contained. Engine-driven hydraulic pump operates the landing gear, flaps, and airbrakes, while an emergency hand pump operates all services. The pneumatic system operates the gun-cocking gear and main wheel brakes; there is no nose wheel brake.

Electrical system is supplied by a 20 V 1,500 W generator on the port engine, charging two 12 V batteries. Remote control two-way radio is mounted in rear fuselage. Beam approach and IFF installation are also fitted.

The Derwent engine was a record breaker from the start. It was designed and the first engine tested within a period of three-and-a-half months, developing no less than 2,000 lb thrust at 16,500 rpm. Rolls-Royce first investigated jet propulsion in 1938, and in 1939 the first designs were made. In 1940 tests were made on various components, and in June, 1941, a plant was set up at Derby for compressor development. At the end of 1941, Rolls-Royce started manufacture of the Whittle-type engine in conjunction with Power Jets.

The first engine, known as the WR-1, was designed for experimental purposes, with low turbine blades stresses — a comparatively big engine for a given thrust. Its dia was 54 in and the design thrust was 2,000 lbs. It weighed only 1,100 lb, and the first engine ran for 35 hr. Two were built, but trouble was experienced with combustion, so extensive development work on combustion chambers and turbine blades was carried out. The restricting factor was construction of the turbine blades, due to limitations of temperature and rpm., but so much progress was made that Rolls-Royce was asked to take over the development and manufacture of the Whittle units.

Meanwhile, a Vickers Wellington aircraft was turned into a flying test plane, with the W2B/23 Whittle engine in the tail, in place of the gun turret. The instrument panel was mounted forward, with remote control to the engine, and in this way 25 hr of flying was carried out, the first engine giving 1,250 lb thrust. A second Wellington was adapted for high-altitude work at 35,000 ft, and is still flying. The first engine passed its 100-hr test in Apr, 1943. It was of 43 in dia and gave a thrust of 1,700 lb for a weight of 850 lb. It was named the Welland because it was the first of the Rolls- Royce River class of jet-propulsion engines. Deliveries of the Welland to the RAF began in May, 1944, when this engine also passed its 500-hr test and went into service with 180 hr between overhauls.

In Apr, 1943, was begun the design of a new jet engine with the same dia and blower, but with a design thrust of 2,000 lb. This unit was completed in 35 months, being on test in July, 1943. It passed its 100-hr test at 2,000 lb in November, and in Apr, 1944, completed its first test flight. This engine was the Derwent, and the Meteor first flew with the new Series I Derwent engines in Mar, 1944, with a thrust of 2,000 lb from each unit for a weight of 920 lb. Further development was immediately undertaken.

A continuous program, involving many 100-hr tests, was carried out, culminating in a successful 500-hr test without strip or major replacement of any kind. The Series II engine gave a 10% improvement in thrust, delivering 2,200 lb. The Series III was an experimental engine to provide suction on the wing surfaces for boundary layer removal. The Series IV gave another 10% increase up to 2,400 lb. thrust. And the Series V (in the Meteor) is an entirely new unit of which nothing more may be disclosed than that it has developed something like twice the thrust of the original engine, thus enabling the Meteor to achieve its remarkable speed.

The Derwent incorporates a centrifugal compressor on the forward end of a shaft carrying a single-stage axial-flow turbine. This main shaft is carried in three bearings and is surrounded by ten combustion chambers, or "cans," which are fed with compressed air from the impeller and with fuel from high-pressure pump. Fuel is governed by a throttle valve controlled by the pilot. An automatic barometric control reduces fuel supply to burners at altitude, similarly to the automatic boost control on supercharged piston engines.

For starting, fuel is ignited by two ignition plugs, and a fuel cut off is provided for stopping the engine. Flame tubes are mounted concentrically within the chambers, and combustion is completed before the gas enters the turbine vane ring at the rear. Balance pipes between combustion chambers equalize pressure and allow the flames to ignite the fuel in adjoining tubes when starting.

Cooling for the air system, center, and rear bearings, and front of turbine disk, is provided by a small centrifugal fan in front of the center bearing. Air enters through short pipes on the engine front housing and passes through the cooling air manifold to the exhaust outlet at the rear.

Lubrication is obtained from a triple-gear-type pump to the bearings. The oil is then collected by two scavenge pumps and passes through a thermostatically controlled oil cooler before being returned to the oil tank. The engine accessories, including fuel and oil pumps, generator, and accessory gear boxes, are mounted on the front of the engine, together with an electric starter. The engine is in a streamlined cowling, having a large air intake in front and a propelling nozzle at the rear.

Following ratings were established when the Derwent completed the 100-hr test: Take off rating, static thrust at sea level, 1,920/2,000 lb; max. rpm, 16,400/16,600; max jet pipe temp 690 deg C; cruising rating, static thrust at sea level, 1,550 lb; max. rpm., 15,000; max jet pipe temp 600 deg C; idling rating, max static thrust at sea level, 120 lb; rpm. 5,000/6,000; and max jet pipe temp 350 deg C.

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This article was originally published in the January, 1946, issue of Aviation magazine, vol 45, no 1, pp 69-72.
The original article includes 6 photos: Photos are not credited. All photos of the Meteor are on the ground.