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Rolls-Royce Merlin

February 14, 2024

For the Packard-produced licensed version, see Packard V-1650 Merlin.

The Rolls-Royce Merlin is a British liquid-cooled V-12 piston aero engine of 27-litres (1,650 cu in) capacity. Rolls-Royce designed the engine and first ran it in 1933 as a private venture. Initially known as the PV-12, it was later called Merlin following the company convention of naming its four-stroke piston aero engines after birds of prey.

Merlin
The Rolls-Royce Merlin
Type Liquid-cooled V-12 four-stroke piston aero engine
National origin United Kingdom
Manufacturer Rolls-Royce Limited
First run 15 October 1933
Major applications Avro Lancaster
de Havilland Mosquito
Handley Page Halifax
Hawker Hurricane
Supermarine Spitfire
Number built 149,659
Variants Packard V-1650 Merlin
Developed into Rolls-Royce Meteor

After several modifications, the first production variants of the PV-12 were completed in 1936. The first operational aircraft to enter service using the Merlin were the Fairey Battle, Hawker Hurricane and Supermarine Spitfire. The Merlin remains most closely associated with the Spitfire and Hurricane, although the majority of the production run was for the four-engined Avro Lancaster heavy bomber. A series of rapidly-applied developments, brought about by wartime needs, markedly improved the engine's performance and durability. Starting at 1,000 horsepower (750 kW) for the first production models, most late war versions produced just under 1,800 horsepower (1,300 kW), and the very latest version as used in the de Havilland Hornet over 2,000 horsepower (1,500 kW).

One of the most successful aircraft engines of the World War II era, some 50 versions of the Merlin were built by Rolls-Royce in Derby, Crewe and Glasgow, as well as by Ford of Britain at their Trafford Park factory, near Manchester. A de-rated version was also the basis of the Rolls-Royce/Rover Meteor tank engine. Post-war, the Merlin was largely superseded by the Rolls-Royce Griffon for military use, with most Merlin variants being designed and built for airliners and military transport aircraft.

The Packard V-1650 was a version of the Merlin built in the United States. Production ceased in 1950 after a total of almost 150,000 engines had been delivered. Merlin engines remain in Royal Air Force service today with the Battle of Britain Memorial Flight, and power many restored aircraft in private ownership worldwide.

Design and development edit

Origin edit

In the early 1930s, Rolls-Royce started planning its future aero-engine development programme and realised there was a need for an engine larger than their 21-litre (1,296 cu in) Kestrel, which was being used with great success in a number of 1930s aircraft.[1] Consequently, work was started on a new 1,100 hp (820 kW)-class design known as the PV-12, with PV standing for Private Venture, 12-cylinder, as the company received no government funding for work on the project. The PV-12 was first run on 15 October 1933 and first flew in a Hawker Hart biplane (serial number K3036) on 21 February 1935.[2] The engine was originally designed to use the evaporative cooling system then in vogue. This proved unreliable and when ethylene glycol from the U.S. became available, the engine was adapted to use a conventional liquid-cooling system. The Hart was subsequently delivered to Rolls-Royce where, as a Merlin testbed, it completed over 100 hours of flying with the Merlin C and E engines.[3]

In 1935, the Air Ministry issued a specification, F10/35, for new fighter aircraft with a minimum airspeed of 310 mph (500 km/h). Fortunately, two designs had been developed: the Supermarine Spitfire and the Hawker Hurricane; the latter designed in response to another specification, F36/34.[4] Both were designed around the PV-12 instead of the Kestrel, and were the only contemporary British fighters to have been so developed. Production contracts for both aircraft were placed in 1936, and development of the PV-12 was given top priority as well as government funding. Following the company convention of naming its piston aero engines after birds of prey, Rolls-Royce named the engine the Merlin after a small, Northern Hemisphere falcon (Falco columbarius).[nb 1][5]

Two more Rolls-Royce engines developed just prior to the war were added to the company's range. The 885 hp (660 kW) Rolls-Royce Peregrine was an updated, supercharged development of their V-12 Kestrel design, while the 1,700 hp (1,300 kW) 42-litre (2,560 cu in) Rolls-Royce Vulture used four Kestrel-sized cylinder blocks fitted to a single crankcase and driving a common crankshaft, forming an X-24 layout.[6] This was to be used in larger aircraft such as the Avro Manchester.[7]

Although the Peregrine appeared to be a satisfactory design, it was never allowed to mature since Rolls-Royce's priority was refining the Merlin. As a result, the Peregrine saw use in only two aircraft: the Westland Whirlwind fighter and one of the Gloster F.9/37 prototypes. The Vulture was fitted to the Avro Manchester bomber, but proved unreliable in service and the planned fighter using it – the Hawker Tornado – was cancelled as a result.[8] With the Merlin itself soon pushing into the 1,500 hp (1,100 kW) range, the Peregrine and Vulture were both cancelled in 1943, and by mid-1943 the Merlin was supplemented in service by the larger Griffon.[9] The Griffon incorporated several design improvements and ultimately superseded the Merlin.

Development edit

Initially the new engine was plagued with problems such as failure of the accessory gear trains and coolant jackets. Several different construction methods were tried before the basic design of the Merlin was set.[10] Early production Merlins were unreliable: common problems were cylinder head cracking, coolant leaks, and excessive wear to the camshafts and crankshaft main bearings.[11]

Early engines edit

The prototype, developmental, and early production engine types were the:

  • PV-12
The initial design using an evaporative cooling system. Two built, passed bench type testing in July 1934, generating 740 hp (550 kW) at 12,000-foot (3,700 m) equivalent. First flown 21 February 1935.[2]
  • Merlin B
Two built, ethylene glycol liquid cooling system introduced. "Ramp" cylinder heads (inlet valves were at a 45-degree angle to the cylinder). Passed Type Testing February 1935, generating 950 hp (710 kW) at 11,000-foot (3,400 m) equivalent.[2]
  • Merlin C
Development of Merlin B; crankcase and cylinder blocks became three separate castings with bolt-on cylinder heads.[2] First flight in Hawker Horsley 21 December 1935, 950 hp (710 kW) at 11,000-foot (3,400 m).[12]
  • Merlin E
Similar to C with minor design changes. Passed 50-hour civil test in December 1935 generating a constant 955 hp (712 kW) and a maximum rating of 1,045 hp (779 kW). Failed military 100-hour test in March 1936. Powered the Supermarine Spitfire prototype.[13]
 
Parallel valve Merlin cylinder head
  • Merlin F (Merlin I)
Similar to C and E. First flight in Horsley 16 July 1936.[14] This became the first production engine, and was designated as the Merlin I. The Merlin continued with the "ramp" head, but this was not a success and only 172 were made. The Fairey Battle I was the first production aircraft to be powered by the Merlin I and first flew on 10 March 1936.[13]
  • Merlin G (Merlin II)
Replaced "ramp" cylinder heads with parallel pattern heads (valve stems parallel to the cylinder bore axis) scaled up from the Kestrel engine. 400-hour flight endurance tests carried out at RAE July 1937; acceptance test 22 September 1937.[14] It was first widely delivered as the 1,030 hp (770 kW) Merlin II in 1938, and production was quickly stepped up for Fairey Battle II.[13]
  • Merlin III
Merlin II with standardised de Havilland/Rotol SBAC propeller shaft, and dual accessory-drive. 1,030 hp (770 kW) at 3,000 rpm at 10,250 feet (3,120 m) at +6.5 lb boost.[15] Formed basis for the Rolls-Royce/Rover Meteor tank engine
  • "Racing" Merlin
Racing engine for 1937/38 "Speed Spitfire" world speed record attempt. Merlin III with strengthened pistons, connecting rods, and gudgeon-pins, running on increased octane fuel, developed 2,160 hp (1,610 kW) at 3,200 rpm and +27 lb boost, a power/weight ratio of 0.621 lb per horsepower. Completed 15-hour endurance run at 1,800 hp (1,300 kW), 3,200 rpm at +22 lb boost.[15]
  • Merlin IV
Merlin with pressure-water cooling for Armstrong Whitworth Whitley IV.
  • Merlin V
Merlin for Fairey Battle V.
  • Merlin VIII
Medium-supercharged Merlin developed for Fairey Fulmar I, rated 1,010 hp (750 kW) at 2,850 rpm at 6,750 feet (2,060 m), 1,080 hp (810 kW) at 3,000 rpm for take-off using 100-octane fuel.[15]
  • Merlin X
First Merlin with two-speed supercharger, 1,145 hp (854 kW) in low gear at 5,250 feet (1,600 m), 1,010 hp (750 kW) in high gear at 17,750 feet (5,410 m). First of Rolls-Royce unitised "Power Plant" installation designs for this engine in 1937[15] and used in Handley Page Halifax I, Vickers Wellington II, and Armstrong Whitworth Whitley V and VII.
  • Merlin XII
Merlin fitted with 0.477:1 reduction gear installed in some Spitfire II's with three-bladed Rotol constant-speed propeller. Rated at 1,150 hp (860 kW) at 3,000 rpm at 14,000 feet (4,300 m).[15]
  • Merlin XX
Merlin X with Stanley Hooker re-designed supercharger[16] incorporating re-designed inlet and improved guide vanes on impeller with revised blower gear ratios; 8:15:1 for low gear, 9:49:1 for high gear. New larger SU twin choke updraught carburettor. Engine interchangeable with Merlin X. Rated at 1,240 hp (920 kW) at 2,850 rpm in low gear at 10,000 feet (3,000 m) and +9 lb boost; 1,175 hp (876 kW) at 2,850 rpm in high gear at 17,500 feet (5,300 m) at +9 lb boost. Revised Rolls-Royce unitised "Power Plant" installation design. Engine used in Bristol Beaufighter II, Boulton Paul Defiant II, Handley Page Halifax II and V, Hawker Hurricane II and IV, and Avro Lancaster I and III. First Merlin produced by Packard Motor Car Company as V-1650-1 and designated by Rolls-Royce as Merlin 28.[15]

Production engines edit

The Merlin II and III series were the first main production versions of the engine. The Merlin III was the first version to incorporate a "universal" propeller shaft, allowing either de Havilland or Rotol manufactured propellers to be used.[17]

The first major version to incorporate changes brought about through experience in operational service was the XX, which was designed to run on 100-octane fuel.[nb 2] This fuel allowed higher manifold pressures, which were achieved by increasing the boost from the centrifugal supercharger. The Merlin XX also utilised the two-speed superchargers designed by Rolls-Royce, resulting in increased power at higher altitudes than previous versions. Another improvement, introduced with the Merlin X, was the use of a 70%–30% water-glycol coolant mix rather than the 100% glycol of the earlier versions. This substantially improved engine life and reliability, removed the fire hazard of the flammable ethylene glycol, and reduced the oil leaks that had been a problem with the early Merlin I, II and III series.[19]

The process of improvement continued, with later versions running on higher octane ratings, delivering more power. Fundamental design changes were also made to all key components, again increasing the engine's life and reliability. By the end of the war the "little" engine was delivering over 1,600 hp (1,200 kW) in common versions, and as much as 2,030 hp (1,510 kW) in the Merlin 130/131 versions specifically designed for the de Havilland Hornet.[20] Ultimately, during tests conducted by Rolls-Royce at Derby, an RM.17.SM (the high altitude version of the Merlin 100-Series) achieved 2,640 hp (1,970 kW) at 36 lb boost (103"Hg) on 150-octane fuel with water injection.[21]

With the end of the war, work on improving Merlin power output was halted and the development effort was concentrated on civil derivatives of the Merlin.[22] Development of what became the "Transport Merlin" (TML)[23] commenced with the Merlin 102 (the first Merlin to complete the new civil type-test requirements) and was aimed at improving reliability and service overhaul periods for airline operators using airliner and transport aircraft such as the Avro Lancastrian, Avro York (Merlin 500-series), Avro Tudor II & IV (Merlin 621), Tudor IVB & V (Merlin 623), TCA Canadair North Star (Merlin 724) and BOAC Argonaut (Merlin 724-IC).[24] By 1951 the time between overhauls (TBO) was typically 650–800 hours depending on use.[25][26] By then single-stage engines had accumulated 2,615,000 engine hours in civil operation, and two-stage engines 1,169,000.[27]

In addition, an exhaust system to reduce noise levels to below those from ejector exhausts was devised for the North Star/Argonaut. This "cross-over" system took the exhaust flow from the inboard bank of cylinders up-and-over the engine before discharging the exhaust stream on the outboard side of the UPP nacelle. As a result, sound levels were reduced by between 5 and 8 decibels. The modified exhaust also conferred an increase in horsepower over the unmodified system of 38 hp (28 kW), resulting in a 5 knot improvement in true air speed. Still-air range of the aircraft was also improved by around 4 per cent.[23] The modified engine was designated the "TMO" and the modified exhaust system was supplied as kit that could be installed on existing engines either by the operator or by Rolls-Royce.[23]

Power ratings for the civil Merlin 600, 620, and 621-series was 1,160 hp (870 kW) continuous cruising at 23,500 feet (7,200 m), and 1,725 hp (1,286 kW) for take-off. Merlins 622–626 were rated at 1,420 hp (1,060 kW) continuous cruising at 18,700 feet (5,700 m), and 1,760 hp (1,310 kW) for take-off. Engines were available with single-stage, two-speed supercharging (500-series), two-stage, two-speed supercharging (600-series), and with full intercooling, or with half intercooling/charge heating, charge heating being employed for cold area use such as in Canada.[24] Civil Merlin engines in airline service flew 7,818,000 air miles in 1946, 17,455,000 in 1947, and 24,850,000 miles in 1948.[28]

Basic component overview (Merlin 61) edit

From Jane's:[29]

Cylinders
Twelve cylinders consisting of high-carbon steel liners set in two, two-piece cylinder blocks of cast "R.R.50" aluminium alloy having separate heads and skirts. Wet liners, ie. coolant in direct contact with external face of liners. Cylinder heads fitted with cast-iron inlet valve guides, phosphor bronze exhaust valve guides, and renewable "Silchrome" steel-alloy valve seats. Two diametrically opposed spark plugs protrude into each combustion chamber.
Pistons
Machined from "R.R.59" alloy forgings. Fully floating hollow gudgeon pins of hardened nickel-chrome steel. Three compression and one oil-control ring above the gudgeon pin, and one oil-control ring below.
Connecting rods
H-section machined nickel-steel forgings, each pair consisting of a plain and a forked rod. The forked rod carries a nickel-steel bearing block which accommodates steel-backed lead-bronze-alloy bearing shells. The "small-end" of each rod houses a floating phosphor bronze bush.
Crankshaft
One-piece, machined from a nitrogen-hardened nickel-chrome molybdenum steel forging. Statically and dynamically balanced. Seven main bearings and six throws.
Crankcase
Two aluminium-alloy castings joined together on the horizontal centreline. The upper portion bears the wheelcase, supercharger and accessories; and carries the cylinder blocks, crankshaft main bearings (split mild-steel shells lined with lead bronze alloy), and part of the housing for the airscrew reduction gear. The lower half forms an oil sump and carries the oil pumps and filters.
Wheelcase
Aluminium casting fitted to rear of crankcase. Houses drives to the camshafts, magnetos, coolant and oil pumps, supercharger, hand and electric starters, and the electric generator.
Valve gear
Two inlet and two exhaust poppet valves of "K.E.965" steel per cylinder. Both the inlet and exhaust valves have hardened "stellited" ends; while the exhaust valves also have sodium-cooled stems, and heads protected with a "Brightray" (nickel-chromium) coating. Each valve is kept closed by a pair of concentric coil-springs. A single, seven-bearing camshaft, located on the top of each cylinder head operates 24 individual steel rockers; 12 pivoting from a rocker shaft on the inner, intake side of the head to actuate the exhaust valves, the others pivoting from a shaft on the exhaust side of the head to actuate the inlet valves.

Technical improvements edit

Most of the Merlin's technical improvements resulted from more efficient superchargers, designed by Stanley Hooker, and the introduction of aviation fuel with increased octane ratings. Numerous detail changes were made internally and externally to the engine to withstand increased power ratings and to incorporate advances in engineering practices.[30]

Ejector exhausts edit
 
Merlin 55 ejector exhaust detail, Spitfire LF.VB, EP120

The Merlin consumed an enormous volume of air at full power (equivalent to the volume of a single-decker bus per minute), and with the exhaust gases exiting at 1,300 mph (2,100 km/h) it was realised that useful thrust could be gained simply by angling the gases backwards instead of venting sideways.

During tests, 70 pounds-force (310 N; 32 kgf) thrust at 300 mph (480 km/h), or roughly 70 hp (52 kW) was obtained, which increased the level maximum speed of the Spitfire by 10 mph (16 km/h) to 360 mph (580 km/h).[31] The first versions of the ejector exhausts featured round outlets, while subsequent versions of the system used "fishtail" style outlets, which marginally increased thrust and reduced exhaust glare for night flying.

In September 1937 the Spitfire prototype, K5054, was fitted with ejector type exhausts. Later marks of the Spitfire used a variation of this exhaust system fitted with forward-facing intake ducts to distribute hot air out to the wing-mounted guns to prevent freezing and stoppages at high altitudes, replacing an earlier system that used heated air from the engine coolant radiator. The latter system had become ineffective due to improvements to the Merlin itself which allowed higher operating altitudes where air temperatures are lower.[32] Ejector exhausts were also fitted to other Merlin-powered aircraft.

Supercharger edit

Central to the success of the Merlin was the supercharger. A.C. Lovesey, an engineer who was a key figure in the design of the Merlin, delivered a lecture on the development of the Merlin in 1946; in this extract he explained the importance of the supercharger:

The impression still prevails that the static capacity known as the swept volume is the basis of comparison of the possible power output for different types of engine, but this is not the case because the output of the engine depends solely on the mass of air it can be made to consume efficiently, and in this respect the supercharger plays the most important role ... the engine has to be capable of dealing with the greater mass flows with respect to cooling, freedom from detonation and capable of withstanding high gas and inertia loads ... During the course of research and development on superchargers it became apparent to us that any further increase in the altitude performance of the Merlin engine necessitated the employment of a two-stage supercharger.[33]

As the Merlin evolved so too did the supercharger; the latter fitting into three broad categories:[34]

  1. Single-stage, single-speed gearbox: Merlin I to III, XII, 30, 40, and 50 series (1937–1942).[nb 3]
  2. Single-stage, two-speed gearbox: experimental Merlin X (1938), production Merlin XX (1940–1945).
  3. Two-stage, two-speed gearbox with intercooler: mainly Merlin 60, 70, and 80 series (1942–1946).

The Merlin supercharger was originally designed to allow the engine to generate maximum power at an altitude of about 16,000 ft (4,900 m). In 1938 Stanley Hooker, an Oxford graduate in applied mathematics, explained "... I soon became very familiar with the construction of the Merlin supercharger and carburettor ... Since the supercharger was at the rear of the engine it had come in for pretty severe design treatment, and the air intake duct to the impeller looked very squashed ..." Tests conducted by Hooker showed the original intake design was inefficient, limiting the performance of the supercharger.[35][nb 4] Hooker subsequently designed a new air intake duct with improved flow characteristics, which increased maximum power at a higher altitude of over 19,000 ft (5,800 m); and also improved the design of both the impeller, and the diffuser which controlled the airflow to it. These modifications led to the development of the single-stage Merlin XX and 45 series.[36]

A significant advance in supercharger design was the incorporation in 1938 of a two-speed drive (designed by the French company Farman) to the impeller of the Merlin X.[37][nb 5] The later Merlin XX incorporated the two-speed drive as well as several improvements that enabled the production rate of Merlins to be increased.[39] The low-ratio gear, which operated from takeoff to an altitude of 10,000 ft (3,000 m), drove the impeller at 21,597 rpm and developed 1,240 hp (920 kW) at that height; while the high gear's (25,148 rpm) power rating was 1,175 hp (876 kW) at 18,000 ft (5,500 m). These figures were achieved at 2,850 rpm engine speed using +9 pounds per square inch (1.66 atm) (48") boost.[40]

In 1940, after receiving a request in March of that year from the Ministry of Aircraft Production for a high-rated (40,000 ft (12,000 m)) Merlin for use as an alternative engine to the turbocharged Hercules VIII used in the prototype high-altitude Vickers Wellington V bomber, Rolls-Royce started experiments on the design of a two-stage supercharger and an engine fitted with this was bench-tested in April 1941, eventually becoming the Merlin 60.[41] The basic design used a modified Vulture supercharger for the first stage while a Merlin 46 supercharger was used for the second.[42] A liquid-cooled intercooler on top of the supercharger casing was used to prevent the compressed air/fuel mixture from becoming too hot.[nb 6] Also considered was an exhaust-driven turbocharger, but although a lower fuel consumption was an advantage, the added weight and the need to add extra ducting for the exhaust flow and waste-gates meant that this option was rejected in favour of the two-stage supercharger.[43] Fitted with the two-stage two-speed supercharger, the Merlin 60 series gained 300 hp (220 kW) at 30,000 ft (9,100 m) over the Merlin 45 series,[42] at which altitude a Spitfire IX was nearly 70 mph (110 km/h) faster than a Spitfire V.[44]

The two-stage Merlin family was extended in 1943 with the Merlin 66, which had its supercharger geared for increased power ratings at low altitudes, and the Merlin 70 series that were designed to deliver increased power at high altitudes.[45]

While the design of the two-stage supercharger forged ahead, Rolls-Royce also continued to develop the single-stage supercharger, resulting in 1942 in the development of a smaller "cropped" impeller for the Merlin 45M and 55M; both of these engines developed greater power at low altitudes.[46] In squadron service the LF.V variant of the Spitfire fitted with these engines became known as the "clipped, clapped, and cropped Spitty" to indicate the shortened wingspan, the less-than-perfect condition of the used airframes, and the cropped supercharger impeller.[47]

Carburettor developments edit
 
Preserved Merlin 63 showing intercooler radiator, supercharger and carburettor

The use of carburettors was calculated to give a higher specific power output, due to the lower temperature, hence greater density, of the fuel/air mixture compared to injected systems.[48] However, the Merlin's float controlled carburettor meant that if Spitfires or Hurricanes were to pitch nose down into a steep dive, negative g-force (g) produced temporary fuel starvation causing the engine to cut-out momentarily. By comparison, the contemporary Bf 109E, which had direct fuel injection, could "bunt" straight into a high-power dive to escape attack. RAF fighter pilots soon learned to avoid this with a "half-roll" of their aircraft before diving in pursuit.[49] A restrictor in the fuel supply line together with a diaphragm fitted in the float chamber, jocularly nicknamed "Miss Shilling's orifice",[nb 7] after its inventor, went some way towards curing fuel starvation in a dive by containing fuel under negative G; however, at less than maximum power a fuel-rich mixture still resulted. Another improvement was made by moving the fuel outlet from the bottom of the S.U. carburettor to exactly halfway up the side, which allowed the fuel to flow equally well under negative or positive g.[50]

Further improvements were introduced throughout the Merlin range: 1943 saw the introduction of a Bendix-Stromberg pressure carburettor that injected fuel at 5 pounds per square inch (34 kPa; 0.34 bar) through a nozzle directly into the supercharger, and was fitted to Merlin 66, 70, 76, 77 and 85 variants. The final development, which was fitted to the 100-series Merlins, was an S.U. injection carburettor that injected fuel into the supercharger using a fuel pump driven as a function of crankshaft speed and engine pressures.[51]

Improved fuels edit
 
Page from Pilot's Notes Merlin II, III and V (A.P.1590B), explaining the use of +12lbs boost and 100 Octane fuel.

At the start of the war, the Merlin I, II and III ran on the then standard 87-octane aviation spirit and could generate just over 1,000 hp (750 kW) from its 27-litre (1,650-cu in) displacement: the maximum boost pressure at which the engine could be run using 87-octane fuel was +6 pounds per square inch (141 kPa; 1.44 atm).[nb 8] However, as early as 1938, at the 16th Paris Air Show, Rolls-Royce displayed two versions of the Merlin rated to use 100-octane fuel. The Merlin R.M.2M was capable of 1,265 hp (943 kW) at 7,870 feet (2,400 m), 1,285 hp (958 kW) at 9,180 feet (2,800 m) and 1,320 hp (980 kW) on take-off; while a Merlin X with a two-speed supercharger in high gear generated 1,150 hp (860 kW) at 15,400 feet (4,700 m) and 1,160 hp (870 kW) at 16,730 feet (5,100 m).[52]

From late 1939, 100-octane fuel became available from the U.S., West Indies, Persia, and, in smaller quantities, domestically,[53] consequently, "... in the first half of 1940 the RAF transferred all Hurricane and Spitfire squadrons to 100 octane fuel."[54] Small modifications were made to Merlin II and III series engines, allowing an increased (emergency) boost pressure of +12 pounds per square inch (183 kPa; 1.85 atm). At this power setting these engines were able to produce 1,310 hp (980 kW) at 9,000 ft (2,700 m) while running at 3,000 revolutions per minute.[55][56] Increased boost could be used indefinitely as there was no mechanical time limit mechanism, but pilots were advised not to use increased boost for more than a maximum of five minutes, and it was considered a "definite overload condition on the engine"; if the pilot resorted to emergency boost he had to report this on landing, when it was noted in the engine log book, while the engineering officer was required to examine the engine and reset the throttle gate.[57] Later versions of the Merlin ran only on 100-octane fuel, and the five-minute combat limitation was raised to +18 pounds per square inch (224 kPa; 2.3 atm).[58]

In late 1943 trials were run of a new "100/150" grade (150-octane) fuel, recognised by its bright-green colour and "awful smell".[59] Initial tests were conducted using 6.5 cubic centimetres (0.23 imp fl oz) of tetraethyllead (T.E.L.) for every one imperial gallon of 100-octane fuel (or 1.43 cc/L or 0.18 U.S. fl oz/U.S. gal), but this mixture resulted in a build-up of lead in the combustion chambers, causing excessive fouling of the spark plugs. Better results were achieved by adding 2.5% mono methyl aniline (M.M.A.) to 100-octane fuel.[60] The new fuel allowed the five-minute boost rating of the Merlin 66 to be raised to +25 pounds per square inch (272 kPa; 2.7 atm).[61] With this boost rating the Merlin 66 generated 2,000 hp (1,500 kW) at sea level and 1,860 hp (1,390 kW) at 10,500 ft (3,200 m).[62]

Starting in March 1944, the Merlin 66-powered Spitfire IXs of two Air Defence of Great Britain (ADGB) squadrons were cleared to use the new fuel for operational trials, and it was put to good use in the summer of 1944 when it enabled Spitfire L.F. Mk. IXs to intercept V-1 flying bombs coming in at low altitudes.[61] 100/150 grade fuel was also used by Mosquito night fighters of the ADGB to intercept V-1s.[63] In early February 1945, Spitfires of the Second Tactical Air Force (2TAF) also began using 100/150 grade fuel.[64][nb 9] This fuel was also offered to the USAAF where it was designated "PPF 44-1" and informally known as "Pep".[66]

Production edit

Production of the Rolls-Royce Merlin was driven by the forethought and determination of Ernest Hives, who at times was enraged by the apparent complacency and lack of urgency encountered in his frequent correspondence with the Air Ministry, the Ministry of Aircraft Production and local authority officials.[67] Hives was an advocate of shadow factories, and, sensing the imminent outbreak of war, pressed ahead with plans to produce the Merlin in sufficient numbers for the rapidly expanding Royal Air Force.[68] Despite the importance of uninterrupted production, several factories were affected by industrial action.[69] By the end of its production run in 1950, 168,176 Merlin engines had been built; over 112,000 in Britain and more than 55,000 under licence in the U.S.[nb 10][56][nb 11]

Derby edit

 
The Marble Hall at the Rolls-Royce factory, Nightingale Road, Derby (photo 2005)

The existing Rolls-Royce facilities at Osmaston, Derby were not suitable for mass engine production although the floor space had been increased by some 25% between 1935 and 1939; Hives planned to build the first two or three hundred engines there until engineering teething troubles had been resolved. To fund this expansion, the Air Ministry had provided a total of £1,927,000 by December 1939.[72][nb 12] Having a workforce that consisted mainly of design engineers and highly skilled men, the Derby factory carried out the majority of development work on the Merlin, with flight testing carried out at nearby RAF Hucknall. All the Merlin-engined aircraft taking part in the Battle of Britain had their engines assembled in the Derby factory. Total Merlin production at Derby was 32,377.[74] The original factory closed in March 2008, but the company maintains a presence in Derby.[75]

Crewe edit

To meet the increasing demand for Merlin engines, Rolls-Royce started building work on a new factory at Crewe in May 1938, with engines leaving the factory in 1939. The Crewe factory had convenient road and rail links to their existing facilities at Derby. Production at Crewe was originally planned to use unskilled labour and sub-contractors with which Hives felt there would be no particular difficulty, but the number of required sub-contracted parts such as crankshafts, camshafts and cylinder liners eventually fell short and the factory was expanded to manufacture these parts "in house".[76]

Initially the local authority promised to build 1,000 new houses to accommodate the workforce by the end of 1938, but by February 1939 it had only awarded a contract for 100. Hives was incensed by this complacency and threatened to move the whole operation, but timely intervention by the Air Ministry improved the situation. In 1940 a strike took place when women replaced men on capstan lathes, the workers' union insisting this was a skilled labour job; however, the men returned to work after 10 days.[77]

Total Merlin production at Crewe was 26,065.[74]

The factory was used postwar for the production of Rolls-Royce and Bentley motor cars and military fighting vehicle power plants. In 1998 Volkswagen AG bought the Bentley marque and the factory. Today it is known as Bentley Crewe.[78]

Glasgow edit

 
Workers assembling cylinder heads on the Hillington Merlin production line in 1942

Hives further recommended that a factory be built near Glasgow to take advantage of the abundant local work force and the supply of steel and forgings from Scottish manufacturers. In September 1939, the Air Ministry allocated £4,500,000 for a new Shadow factory.[79][nb 13] This government-funded and -operated factory was built at Hillington starting in June 1939 with workers moving into the premises in October, one month after the outbreak of war. The factory was fully occupied by September 1940. A housing crisis also occurred at Glasgow, where Hives again asked the Air Ministry to step in.[81]

With 16,000 employees, the Glasgow factory was one of the largest industrial operations in Scotland. Unlike the Derby and Crewe plants, which relied significantly on external subcontractors, it produced almost all the Merlin's components itself.[82] Hillingdon required "a great deal of attention from Hives" from when it was producing its first complete engine; it had the highest proportion of unskilled workers in any Rolls-Royce-managed factory”.[83] Engines began to leave the production line in November 1940, and by June 1941 monthly output had reached 200, increasing to more than 400 per month by March 1942.[84] In total 23,675 engines were produced. Worker absenteeism became a problem after some months due to the physical and mental effects of wartime conditions such as the frequent occupation of air-raid shelters. It was agreed to cut the punishing working hours slightly to 82 hours a week, with one half-Sunday per month awarded as holiday.[85] Record production is reported to have been 100 engines in one day.[86]

Immediately after the war the site repaired and overhauled Merlin and Griffon engines, and continued to manufacture spare parts.[86] Finally, following the production of the Rolls-Royce Avon turbojet and others, the factory was closed in 2005.[87]

Manchester edit

Main article: Ford Trafford Park Factory

The Ford Motor Company was asked to produce Merlins at Trafford Park, Stretford, near Manchester, and building work on a new factory was started in May 1940 on a 118-acre (48 ha) site. Built with two distinct sections to minimise potential bomb damage, it was completed in May 1941 and bombed in the same month.[nb 14] At first, the factory had difficulty in attracting suitable labour, and large numbers of women, youths and untrained men had to be taken on. Despite this, the first Merlin engine came off the production line one month later and it was building the engine at a rate of 200 per week by 1943,[88] at which point the joint factories were producing 18,000 Merlins per year.[34] In his autobiography Not much of an Engineer, Sir Stanley Hooker states: "... once the great Ford factory at Manchester started production, Merlins came out like shelling peas ...".[89]

Some 17,316 people worked at the Trafford Park plant, including 7,260 women and two resident doctors and nurses.[88] Merlin production started to run down in August 1945, and finally ceased on 23 March 1946.[90]

Total Merlin production at Trafford Park was 30,428.[74]

Packard V-1650 edit

Main article: Packard V-1650 Merlin

As the Merlin was considered to be so important to the war effort, negotiations were started to establish an alternative production line outside the UK. Rolls-Royce staff visited North American automobile manufacturers to select one to build the Merlin in the U.S. or Canada. Henry Ford rescinded an initial offer to build the engine in the U.S. in July 1940, and the Packard Motor Car Company was selected to take on the $130,000,000 Merlin order (equivalent to $2.72 billion in 2022 dollars[91]).[92] Agreement was reached in September 1940, and the first Packard-built engine, a Merlin XX, designated the V-1650-1, ran in August 1941.[93] Total Merlin production by Packard was 55,523.[74]

Six development engines were also made by Continental Motors, Inc.[74]

Variants edit

Main article: List of Rolls-Royce Merlin variants

This is a list of representative Merlin variants, describing some of the mechanical changes made during development of the Merlin. Engines of the same power output were typically assigned different model numbers based on supercharger or propeller gear ratios, differences in cooling system or carburettors, engine block construction, or arrangement of engine controls.[94] Power ratings quoted are usually maximum "military" power. All but the Merlin 131 and 134 engines were "right-hand tractor", i.e. the propeller rotated clockwise when viewed from the rear. In addition to the mark numbers, Merlin engines were allocated experimental numbers by the Ministry of Supply (MoS) – e.g.: RM 8SM for the Merlin 61 and some variants – while under development; these numbers are noted where possible.[95] Merlin engines used in Spitfires, apart from the Merlin 61, used a propeller reduction ratio of .477:1. Merlins used in bombers and other fighters used a ratio of .42:1.[96]

Data from Bridgman (Jane's)[97] unless otherwise noted:

  • Merlin II (RM 1S)
1,030 hp (770 kW) at 3,000 rpm at 5,500 ft (1,676 m) using + 6 psi boost (41 kPa gauge; or an absolute pressure of 144 kPa or 1.41 atm); used 100% glycol coolant. First production Merlin II delivered 10 August 1937.[14] Merlin II used in the Boulton Paul Defiant, Hawker Hurricane Mk.I, Supermarine Spitfire Mk.I fighters, and Fairey Battle light bomber.[98]

  • Merlin III (RM 1S)
Merlin III fitted with "universal" propeller shaft able to mount either de Havilland or Rotol propellers.[99] From late 1939, using 100-octane fuel and +12 psi boost (83 kPa gauge; or an absolute pressure of 184 kPa or 1.82 atm), the Merlin III developed 1,310 hp (980 kW) at 3,000 rpm at 9,000 ft (2,700 m);[55] using 87-octane fuel the power ratings were the same as the Merlin II. Used in the Defiant, Hurricane Mk.I, Spitfire Mk.I fighters, and Battle light bomber.[98] First production Merlin III delivered 1 July 1938.[14]

  • Merlin X (RM 1SM)
1,130 hp (840 kW) at 3,000 rpm at 5,250 ft (1,600 m); maximum boost pressure +10 psi; this was the first production Merlin to use a two-speed supercharger; Used in Halifax Mk.I, Wellington Mk.II, and Whitley Mk.V bombers. First production Merlin X, 5 December 1938.[14]

  • Merlin XII (RM 3S)
1,150 hp (860 kW); fitted with Coffman engine starter; first version to use 70/30% water/glycol coolant rather than 100% glycol. Reinforced construction, able to use constant boost pressure of up to +12 psi using 100-octane fuel; Used in Spitfire Mk.II.[99] First production Merlin XII, 2 September 1939.[14]
 
Preserved Merlin XX at the Royal Air Force Museum London

  • Merlin XX (RM 3SM)
1,480 hp (1,100 kW) at 3,000 rpm at 6,000 ft (1,829 m); two-speed supercharger; boost pressure of up to +14 psi; Used in Hurricane Mk.II, Beaufighter Mk.II, Halifax Mk.II and Lancaster Mk.I bombers, and in the Spitfire Mk.III prototypes (N3297 & W3237).[100] First production Merlin XX, 4 July 1940.[14][nb 15]

  • Merlin 32 (RM 5M)
1,645 hp (1,227 kW) at 3,000 rpm at 2,500 ft (762 m); a "low altitude" version of Merlin with cropped supercharger impellers for increased power at lower altitudes and a maximum boost pressure of +18 psi; fitted with Coffman engine starter; used mainly in Fleet Air Arm aircraft, mainly the Fairey Barracuda Mk.II torpedo bomber and Supermarine Seafire F. Mk.IIc fighters. Also Hurricane Mk.V and Spitfire P.R. Mk.XIII.[99] First production Merlin 32, 17 June 1942.[14]

  • Merlin 45 (RM 5S)
1,515 hp (1,130 kW) at 3,000 rpm at 11,000 ft (3,353 m); used in Spitfire Mk.V, PR.Mk.IV and PR.Mk.VII, Seafire Ib and IIc. Maximum boost pressure of +16 psi. First production Merlin 45, 13 January 1941.[14]

  • Merlin 47 (RM 6S)
1,415 hp (1,055 kW) at 3,000 rpm at 14,000 ft (4,267 m); high-altitude version used in Spitfire H.F.Mk.VI. Adapted with a Marshall compressor (often called a "blower") to pressurise the cockpit. First production Merlin 47, 2 December 1941.[14]

  • Merlin 50.M (RM 5S)
1,585 hp (1,182 kW) at 3,000 rpm at 3,800 ft (1,158 m); low-altitude version with supercharger impeller "cropped" to 9.5 in (241 mm) in diameter. Permitted boost was +18 psi (125 kPa gauge; or an absolute pressure of 225 kPa or 2.2 atm) instead of +16 psi (110 kPa gauge; or an absolute pressure of 210 kPa or 2.08 atm) on a normal Merlin 50 engine.[101][102] Merlin 50 series was first to use the Bendix-Stromberg "negative-g" carburettor.[103]

  • Merlin 61 (RM 8SM)
1,565 hp (1,167 kW) at 3,000 rpm at 12,250 ft (3,734 m), 1,390 hp (1,040 kW) at 3,000 rpm at 23,500 ft (7,163 m); fitted with a new two-speed two-stage supercharger providing increased power at medium to high altitudes; +15 psi boost; used in Spitfire F Mk.IX, and P.R Mk.XI.[104] First British production variant to incorporate two-piece cylinder blocks designed by Rolls-Royce for the Packard Merlin.[105] Reduction gear ratio .42:1, with gears for pressurisation pump.[106] First production Merlin 61, 2 March 1942.[14]

  • Merlin 63 & 63A
1,710 hp (1,280 kW) at 3,000 rpm at 8,500 ft (2,591 m), 1,505 hp (1,122 kW) at 3,000 rpm at 21,000 ft (6,401 m); strengthened two-speed two-stage development of Merlin 61; +18 psi boost; Reduction gear ratio .477:1; Merlin 63A did not have extra gears for pressurisation and incorporated a strengthened supercharger drive quill shaft.[107] Used in Spitfire F Mk.VIII and F. Mk. IX.[101]
Audio of RR Merlin 66/266 starting

  • Merlin 66 (RM 10SM)
1,720 hp (1,280 kW) at 5,790 ft (1,765 m) using +18 psi boost (124 kPa gauge; or an absolute pressure of 225 kPa or 2.2 atm); low-altitude version of Merlin 63A. Fitted with a Bendix-Stromberg anti-g carburettor;[108] intercooler used a separate header tank.[109] Used in Spitfire L.F. Mk.VIII and L.F. Mk.IX.[101]

  • Merlin 76/77 (RM 16SM)[43]
1,233 hp (919 kW) at 35,000 ft (10,668 m);[43] Fitted with a two-speed, two-stage supercharger and a Bendix-Stromberg carburettor. Dedicated "high altitude" version used in the Westland Welkin high-altitude fighter and some later Spitfire and de Havilland Mosquito variants. The odd-numbered mark drove a Marshall Roots-type blower for cockpit pressurising.

  • Merlin 130/131
2,060 hp (1,540 kW); redesigned "slimline" versions for the de Havilland Hornet. Engine design modified to decrease frontal area to a minimum and was the first Merlin series to use down-draught induction systems. Coolant pump moved from the bottom of the engine to the starboard side. Two-speed, two-stage supercharger and S.U. injection carburettor. Corliss throttle. Maximum boost was 25 psi (170 kPa) gauge; or an absolute pressure of 270 kPa or 2.7 atm). On the Hornet the Merlin 130 was fitted in the port nacelle: the Merlin 131, fitted in the starboard nacelle, was converted to a "reverse" or left-hand tractor engine using an additional idler gear in the reduction gear casing.[110]

  • Merlin 133/134
2,030 hp (1,510 kW); derated for use at low altitude 130/131 variants used in Sea Hornet F. Mk. 20, N.F. Mk. 21 and P.R. Mk. 22. Maximum boost was lowered to +18 psi gauge (230 kPa or 2.2 atm absolute).
  • Merlin 266 (RM 10SM)
The prefix "2" indicates engines built by Packard, otherwise as Merlin 66, optimised for low-altitude operation. Fitted to the Spitfire Mk.XVI.[101]

  • Merlin 620
1,175 hp (876 kW) continuous cruising using 2,650 rpm at +9 psi boost (62 kPa gauge; or an absolute pressure of 165 kPa or 1.6 atm); capable of emergency rating of 1,795 hp (1,339 kW) at 3,000 rpm using +20 psi boost (138 kPa gauge; or an absolute pressure of 241 kPa or 2.4 atm); civilian engine developed from Merlin 102; two-stage supercharger optimised for medium altitudes, and used an S.U. injection carburettor. "Universal Power Plant" (UPP) standardised annular radiator installation development of that used on Lancaster VI and Avro Lincoln. The Merlin 620–621 series was designed to operate in the severe climatic conditions encountered on Canadian and long-range North Atlantic air routes. Used in Avro Tudor, Avro York, and the Canadair North Star.[111]

Applications edit

In chronological order, the first operational aircraft powered by the Merlin to enter service were the Fairey Battle, Hawker Hurricane, and Supermarine Spitfire.[112] Although the engine is most closely associated with the Spitfire, the four-engined Avro Lancaster was the most numerous application, followed by the twin-engined de Havilland Mosquito.[113]

List from Lumsden 2003[114][nb 16]

Postwar edit

At the end of World War II, new versions of the Merlin (the 600- and 700-series) were designed and produced for use in commercial airliners such as the Avro Tudor, military transport aircraft such as the Avro York, and the Canadair North Star which performed in both roles. These engines were basically military specification with some minor changes to suit the different operating environment.[115]

A Spanish-built version of the Messerschmitt Bf 109 G-2, the 1954 Hispano Aviación HA-1112-M1L Buchon, was built in Hispano's factory in Seville with the Rolls-Royce Merlin 500/45 engine of 1,600 horsepower (1,200 kW) – a fitting powerplant for the last-produced version of the famous Messerschmitt fighter, as the Bf 109 V1 prototype aircraft had been powered by the Rolls-Royce Kestrel V-12 engine in 1935.[116]

The CASA 2.111 was another Spanish-built version of a German aircraft, the Heinkel He 111, that was adapted to use the Merlin after the supply of Junkers Jumo 211F-2 engines ran out at the end of the war.[117] A similar situation existed with the Fiat G.59 when available stocks of the Italian licence-built version of the Daimler-Benz DB 605 engine ran short.[118]

The Australian built Avro Lincoln from A73-51 used Australian built Commonwealth Aircraft Corporation Merlin 102s. A total of 108 CAC Merlins were built by the time production ended.

Alternative applications edit

Further information: Rolls-Royce Merlin alternative uses

A non-supercharged version of the Merlin using a larger proportion of steel and iron components was produced for use in tanks. This engine, the Rolls-Royce Meteor, in turn led to the smaller Rolls-Royce Meteorite.[119] In 1943, further Meteor development was handed over to Rover, in exchange for Rover's gas turbine interests.[120]

In 1938, Rolls-Royce started work on modifying some Merlins which were later to be used in British MTBs, MGBs, and RAF Air-Sea Rescue Launches. For these the superchargers were modified single-stage units and the engine was re-engineered for use in a marine environment. Some 70 engines were converted before priority was given to producing aero engines.[121]

Experiments were carried out by the Irish Army involving replacing the Bedford engine of a Churchill tank with a Rolls-Royce Merlin engine salvaged from an Irish Air Corps Seafire aircraft. The experiment was not a success, although the reasons are not recorded.[122]

Surviving engines edit

One of the most successful of the World War II era aircraft engines, the Merlin continues to be used in many restored World War II vintage aircraft all over the world. The Royal Air Force Battle of Britain Memorial Flight is a notable current operator of the Merlin. In England the Shuttleworth Collection owns and operates a Merlin-powered Hawker Sea Hurricane IB and a Supermarine Spitfire VC – Both can be seen flying at home displays throughout the summer months.[123][124]

Engines on display edit

Merlin24 ground demonstration

Preserved examples of the Rolls-Royce Merlin are on display at the following museums:

Specifications (Merlin 61) edit

 
Rolls-Royce Merlin with components labelled

Data from Jane's.[136]

General characteristics

  • Type: 12-cylinder, supercharged, liquid-cooled, 60° "Vee", SOHC, piston aircraft engine.
  • Bore: 5.4 in (137 mm)
  • Stroke: 6.0 in (152 mm)
  • Displacement: 1,649 cu in (27 L)
  • Length: 88.7 in (225 cm)
  • Width: 30.8 in (78 cm)
  • Height: 40 in (102 cm)
  • Dry weight: 1,640 lb (744 kg)[nb 17]

Components

Performance

  • Power output: * 1,290 hp (960 kW) at 3,000 rpm at take-off.
  • 1,565 hp (1,167 kW) at 3,000 rpm at 12,250 ft (3,730 m), MS gear)[nb 18]
  • 1,580 hp (1,180 kW) at 3,000 rpm at 23,500 ft (7,200 m), FS gear)
  • Specific power: 0.96 hp/cu in (43.6 kW/L)
  • Compression ratio: 6:1
  • Fuel consumption: Minimum 30 Imp gal/h (136 L/h), maximum 130 Imp gal/h (591 L/h)[nb 19]
  • Power-to-weight ratio: 0.96 hp/lb (1.58 kW/kg) at maximum power.

See also edit

Related development

Comparable engines

Related lists

References edit

Footnotes edit

  1. ^ The naming tradition was started by managing director, Claude Johnson, in 1915 with the Eagle, Hawk and Falcon engines. There is no connection to King Arthur's legendary magician.
  2. ^ The Merlin II and III series were originally designed to use 87-octane fuel and later modified to allow the use of 100-octane fuel.[18]
  3. ^ Because of an accelerated design process the timelines of Merlin development overlapped; for example, the two-stage supercharger was being designed before there was a need to introduce the modified Merlin 45M and 55Ms to counteract the threat of the Focke-Wulf Fw 190.
  4. ^ The function of the supercharger is to compress the fuel/air mixture entering the engine cylinders; any pressure loss to the impeller (also called the rotor) would impair the supercharger's efficiency.
  5. ^ Rolls-Royce took out a licence in 1938 to build the two-speed drive.[38]
  6. ^ A hot mixture could either pre-ignite before reaching the engine's cylinders or detonate in the engine.
  7. ^ Invented in March 1941 by Beatrice Shilling, an engineer at the Royal Aircraft Establishment, Farnborough.
  8. ^ The British measured boost pressure as lbf/sq in (or psi), and commonly referred to it as "pounds" of boost. The normal atmospheric pressure at sea level is 14.5 psi (1,000 mbar), thus a reading of +6 means that the air/fuel mix is being compressed by a supercharger blower to 20.5 psi before entering the engine; +25 means that the air/fuel mix is now being compressed to 39.5 psi.
  9. ^ Monty Berger, Senior Intelligence Officer of 126(RCAF) Spitfire Wing, 2 TAF, alleged that there were still problems being experienced with the new fuel on his wing, which was mistrusted by many pilots in the Wing.[64] However, another source states that the transition to 150 Grade went without problems.[65]
  10. ^ Factory production numbers:
    • Rolls-Royce: Derby = 32,377
    • Rolls-Royce: Crewe = 26,065
    • Rolls-Royce: Glasgow =23,675
    • Ford Manchester= 30,428
    • Packard Motor Corp = 55,523 (37,143 Merlins, 18,380 V-1650s)
    • Commonwealth Aircraft Corp (CAC): NSW Australia =108 Type MK102. 1946–1952 for the CAC Avro Lincoln[70]
    • Overall: 168,176
  11. ^ Cost: £2,000 (engine), £350 (propeller)[71]
  12. ^ The Crewe works in fact had been leased to Rolls-Royce by the government.[73]
  13. ^ This allocation had increased to £5,995,000 by December 1939.[80]
  14. ^ The new factory was bombed by the Luftwaffe in May 1941.[88]
  15. ^ In August 1940 drawings of the Merlin XX were sent to the Packard Motor Car Company and used as the basis for the Packard Merlin 28.[14]
  16. ^ Lumsden covers British aircraft only, the Merlin may not be the main powerplant for these types; for example, one or two Hawker Harts and Horsleys were used to test early versions of the Merlin.
  17. ^ Plus 2.5% tolerance
  18. ^ MS and FS refer to the supercharger blower speeds: Moderate/Fully Supercharged. Moderate Supercharging referred to low- to medium-altitudes operation, Full Supercharging to medium- to high-altitude operation[137]
  19. ^ Ref: A.P. 1565 I, P & L: Pilot's Notes for Spitfire IX, XI and XVI fuel consumption dependent on throttle, mixture and boost settings, plus altitude.

Citations edit

  1. ^ Rubbra 1990, p. 64.
  2. ^ a b c d Lumsden 2003, p. 203.
  3. ^ Mason 1991, p. 168.
  4. ^ McKinstry 2007, p. 53.
  5. ^ Gunston 1989, p. 137.
  6. ^ Rubbra 1990, p. 139.
  7. ^ Lumsden 2003, pp. 198–200.
  8. ^ Lumsden 2003, p. 200.
  9. ^ Rubbra 1990, p. 118.
  10. ^ Rubbra 1990, pp. 64–117.
  11. ^ Rubbra 1990, pp. 82–92.
  12. ^ Morgan and Shacklady 2000, p. 607.
  13. ^ a b c Lumsden 2003, p. 204.
  14. ^ a b c d e f g h i j k l Morgan and Shacklady 2000, p. 610.
  15. ^ a b c d e f King, H. F. (7 May 1954). . Flight. p. 577. Archived from the original on 11 February 2017. Retrieved 22 August 2017.
  16. ^ "World Encyclopedia of Aero Engines – 5th edition" by Bill Gunston, Sutton Publishing, 2006, p. 190
  17. ^ Fozard 1991, p. 125.
  18. ^ Air Ministry 1940, pp. 6, 10.
  19. ^ Fozard 1991, pp. 127, 165.
  20. ^ Flight January 1946, p. 93.
  21. ^ Lovesey 1946, p. 223.
  22. ^ Lovesey 1946, p. 224.
  23. ^ a b c . Flight. 29 February 1952. p. 242. Archived from the original on 31 January 2018. Retrieved 22 August 2017.
  24. ^ a b King, H. F. (7 May 1954). . Flight. p. 579. Archived from the original on 11 February 2017. Retrieved 22 August 2017.
  25. ^ . Flight. 13 February 1947. p. 162. Archived from the original on 31 January 2018. Retrieved 22 August 2017.
  26. ^ King, H. F. (24 February 1949). . Flight. p. 215. Archived from the original on 31 January 2018. Retrieved 22 August 2017.
  27. ^ . Flight. 31 August 1951. p. 249. Archived from the original on 31 January 2018. Retrieved 22 August 2017.
  28. ^ "The Rolls Royce Civil Merlin Engine". Flight. 16 June 1949. from the original on 31 January 2018. Retrieved 22 August 2017.
  29. ^ Bridgman 1998, pp. 280–281.
  30. ^ Lovesey 1946, pp. 224–226.
  31. ^ Price 1982, p. 51.
  32. ^ Tanner 1981, A.P.1565E, Vol.1, Section II.
  33. ^ Lovesey 1946, p. 218.
  34. ^ a b Lumsden 2003, p. 201.
  35. ^ Hooker 1984, p. 45.
  36. ^ Hooker 1984, pp. 46–50, 52, 235–247.
  37. ^ Lumsden 2003, p. 206.
  38. ^ Rubbra 1990, p. 71.
  39. ^ Smith February 1942 p. b.
  40. ^ Smith February 1942 p. d.
  41. ^ King 1954, p. 578.
  42. ^ a b Lovesey 1946, p. 220.
  43. ^ a b c Lovesey 1946, p. 219.
  44. ^ Price 1982, pp. 142, 167.
  45. ^ Price 1982, pp. 153–154, 170.
  46. ^ Lumsden 2003, p. 210.
  47. ^ Price 1982, p. 135.
  48. ^ Hooker 1984, p. 62.
  49. ^ McKinstry 2007, p. 205.
  50. ^ Smallwood 1996, p. 135.
  51. ^ Lumsden 2003, p. 212.
  52. ^ Flight 1938, p. 528.
  53. ^ Payton-Smith 1971, pp. 259–260.
  54. ^ Lloyd, p. 139
  55. ^ a b Harvey-Bailey 1995, p. 155.
  56. ^ a b Gunston, p. 144.
  57. ^ Air Ministry 1940.
  58. ^ Air Ministry 1943, p. 25.
  59. ^ McKinstry 2007, p. 356.
  60. ^ Lovesey 1946, pp. 222–223.
  61. ^ a b Price 1982. p. 170.
  62. ^ Wilkinson 1946, p. 195.
  63. ^ Simons 2011, pp. 126–127.
  64. ^ a b Berger and Street 1994. p. 199.
  65. ^ Nijboer 2010, p. 100.
  66. ^ "Fuel". napoleon130.tripod.com. from the original on 11 February 2017. Retrieved 22 June 2017.
  67. ^ Pugh 2000, pp. 195–196.
  68. ^ Pugh 2000, pp. 193–194.
  69. ^ McKinstry 2007, pp. 327–329.
  70. ^ RAAF Museum Point Cook
  71. ^ Beckles 1941, pp. 78–79. (1940 prices, unadjusted for inflation).
  72. ^ War Cabinet-Supply and Production: Fourth Report by the Air Ministry, Appendix V, sheet 3. 8 March 2016 at the Wayback Machine National Archives.gov.uk. Retrieved: 8 March 2016.
  73. ^ Harvey-Bailey 1995, p. 12.
  74. ^ a b c d e Gunston 2006, p. 190.
  75. ^ Derby factory closure 3 April 2008 at the Wayback Machine news.bbc.co.uk. Retrieved: 24 August 2009
  76. ^ Pugh 2000, p. 193.
  77. ^ Pugh 2000, pp. 196–197.
  78. ^ Crewe factory history 5 March 2012 at the Wayback Machine jackbarclayparts.co.uk. Retrieved: 24 August 2009
  79. ^ War Cabinet-Supply and Production: First Report by the Air Ministry, Appendix XI. 8 March 2016 at the Wayback Machine National Archives.gov.uk. Retrieved: 8 March 2016.
  80. ^ War Cabinet-Supply and Production: Fourth Report by the Air Ministry, Appendix XI. 8 March 2016 at the Wayback Machine National Archives.gov.uk. Retrieved: 8 March 2016.
  81. ^ Pugh 2000, p. 197.
  82. ^ Lloyd and Pugh 2004, p. 61.
  83. ^ Robotham 1970, p. 127.
  84. ^ Lloyd and Pugh 2004, p. 69.
  85. ^ Pugh 2000, p. 198.
  86. ^ a b End of era for Rolls-Royce plant. news.bbc.co.uk. Retrieved: 25 August 2009
  87. ^ Hillington factory history 7 August 2009 at the Wayback Machine rolls-royce.com. Retrieved: 24 August 2009
  88. ^ a b c Nicholls 1996, p. 103.
  89. ^ Hooker 1984, pp. 58–59.
  90. ^ Nicholls 1996, p. 105.
  91. ^ 1634–1699: McCusker, J. J. (1997). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda (PDF). American Antiquarian Society. 1700–1799: McCusker, J. J. (1992). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States (PDF). American Antiquarian Society. 1800–present: Federal Reserve Bank of Minneapolis. "Consumer Price Index (estimate) 1800–". Retrieved 28 May 2023.
  92. ^ Time Magazine (8 July 1940) – Business: Ford's Rolls-Royces. 21 July 2013 at the Wayback Machine time.com. Retrieved: 26 August 2009
  93. ^ Lumsden 2003, p. 202.
  94. ^ Bridgman 1998, p. 283.
  95. ^ Morgan and Shacklady 2000, p. 608.
  96. ^ Harvey-Bailey, 1995, p. 62.
  97. ^ Bridgman 1998, pp. 281–283.
  98. ^ a b Bridgman 1998, p. 281.
  99. ^ a b c Robertson 1973, p. 144.
  100. ^ Morgan and Shacklady 2000, p. 129.
  101. ^ a b c d Robertson 1973, p. 145.
  102. ^ Price 1982, p. 145.
  103. ^ Matusiak 2004, p. 10.
  104. ^ Smith 1942, pp. 655–659.
  105. ^ a b Smith 1942, p. 656.
  106. ^ Harvey-Bailey 1995, pp. 62, 169.
  107. ^ Harvey-Bailey 1995, p. 170
  108. ^ Air Ministry 1943, p. 6.
  109. ^ Harvey-Bailey 195, p. 172.
  110. ^ "Flight 1946, pp. 92–94". flightglobal.com. from the original on 29 July 2017. Retrieved 22 June 2017.
  111. ^ Flight July 1946, p. 99.
  112. ^ Lumsden 2003, p. 205.
  113. ^ Lumsden 2003, pp. 208–209.
  114. ^ Lumsden 2003, pp. 203–215.
  115. ^ Lumsden 2003, pp. 214–215.
  116. ^ Lumsden 2003, p. 214.
  117. ^ Wilson, Randy. It's a Heinkel: the Luftwaffe's workhorse Heinkel 111 bomber 28 September 2006 at the Wayback Machine rwebs.net, The Dispatch. Volume 12, Number 4, Winter 1996. Retrieved: 6 September 2009
  118. ^ Green and Swanborough 1994, p. 211.
  119. ^ Pugh 2000, p. 254.
  120. ^ Harvey-bailey 1995, p. 83.
  121. ^ Harvey-Bailey 1995, pp. 83–84.
  122. ^ Martin 2002, p. 58.
  123. ^ The Shuttleworth Collection – Hawker Sea Hurricane IB www.shuttleworth.org. Retrieved: 23 July 2019
  124. ^ The Shuttleworth Collection – Spitfire VC www.shuttleworth.org. Retrieved: 23 July 2019
  125. ^ Photo and factfile. 12 March 2016 at the Wayback Machine Retrieved: 12 March 2016.
  126. ^ Merlin 60 or 70 series from Spitfire VIII. 29 October 2014 at the Wayback Machine Retrieved: 12 March 2016.
  127. ^ "Engines List". City of Norwich Aviation Museum. Retrieved 27 August 2023.
  128. ^ Merlins from crashed bomber. 21 April 2014 at the Wayback Machine Retrieved: 12 March 2016.
  129. ^ Merlin XX. 12 March 2016 at the Wayback Machine Retrieved: 12 March 2016.
  130. ^ "Introducing the Merlin" via the BBC (requires plug-in that may not work on some browsers). 9 May 2016 at the Wayback Machine Retrieved: 12 March 2016.
  131. ^ Merlin 28, Cosford 12 March 2016 at the Wayback Machine Retrieved: 12 March 2016.
  132. ^ Science Museum website 29 October 2010 at the Wayback Machine Retrieved: 12 March 2016.
  133. ^ Shuttleworth website 6 August 2013 at the Wayback Machine Retrieved: 12 March 2016.
  134. ^ Smithsonian National Air and Space Museum 6 July 2016 at the Wayback Machine Retrieved: 3 March 2017.
  135. ^ Wings Museum 13 March 2013 at the Wayback Machine Retrieved: 12 March 2016.
  136. ^ Bridgman 1998, pp. 280–282.
  137. ^ "Development of the Aircraft Supercharger". Flightglobal Archive. from the original on 29 October 2014.

Bibliography edit

  • Air Ministry. A.P 1509B/J.2-W Merlin II and III Aero Engines (June 1940). London: Air Ministry, 1940.
  • Air Ministry. A.P 1565B Spitfire IIA and IIB Aeroplanes: Merlin XII Engine, Pilot's Notes (July 1940). London: Air Data Publications, 1972 (reprint). ISBN 0-85979-043-6.
  • Air Ministry. Pilot's Notes for Spitfire Mark F.VII – Merlin 64 or 71 engine; Mark F.VIII – Merlin 63,66 or 70 engine. Air Publication 1565G & H -P.N. London, UK: Air Ministry, December 1943.
  • Beckles, Gordon. Birth of a Spitfire: The Story of Beaverbook's Ministry and its First £10,000,000. London: Collins Clear-Type Press, 1941.
  • Berger, Monty and Street, Brian Jeffrey. Invasion Without Tears. Toronto, Canada: Random House, 1994. ISBN 0-394-22277-6.
  • Bridgman, L. Jane's Fighting Aircraft of World War II. London: Crescent, 1998. ISBN 0-517-67964-7
  • Fozard, John W.Sydney Camm and the Hurricane; Perspectives on the Master Fighter Designer and his Finest Achievement. Shrewsbury, UK: Airlife, 1991. ISBN 1-85310-270-9.
  • Green, William and Swanborough, Gordon. The Complete Book of Fighters. New York: Smithmark Publishers, 1994. ISBN 0-8317-3939-8.
  • Gunston, Bill World Encyclopedia of Aero Engines (5th Edition). Stroud, UK: Sutton Publishing, 2006. ISBN 0-7509-4479-X
  • Harvey-Bailey, A. The Merlin in Perspective – The Combat Years (4th edition) Derby, England: Rolls-Royce Heritage Trust, 1995. ISBN 1-872922-06-6
  • Hooker, Stanley Not Much of an Engineer London: Airlife, 1984. ISBN 1-85310-285-7.
  • King, H. F. "The Two R's: A Commemorative History of Rolls-Royce Aero Engines. (article and images)." Flight No. 2363, Volume 65, 7 May 1954.
  • Lloyd, Ian and Pugh, Peter. Hives & the Merlin. Cambridge, England: Icon Books, 2004. ISBN 1-84046-644-8
  • Lovesey, A C. "Development of the Rolls-Royce Merlin from 1939 to 1945." Aircraft Engineering and Aerospace Technology, Volume 18, Issue 7. London, MCB UP Ltd., July 1946. ISSN 0002-2667.
  • Lumsden, Alec. British Piston Engines and Their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.
  • Martin, Karl. Irish Army Vehicles, Transport and Armour since 1922. 2002. ISBN 0-9543413-0-9.
  • Mason, Francis K. Hawker Aircraft Since 1920 (3rd revised edition). London: Putnam, 1991. ISBN 0-85177-839-9.
  • Matusiak, Wojtek. Supermarine Spitfire Mk V: Mushroom Model Magazine Special, No. 6111. Redbourn, UK: Mushroom Model Publications, 2004. ISBN 83-917178-3-6
  • McKinstry, Leo. Spitfire – Portrait of a Legend. London: John Murray, 2007. ISBN 0-7195-6874-9.
  • Morgan, Eric B. and Edward Shacklady. Spitfire: The History. London: Key Publishing, 2000. ISBN 0-946219-48-6.
  • Nicholls, Robert. Trafford Park: the First Hundred Years. Phillimore & Co. Ltd., 1996. ISBN 1-86077-013-4.
  • Nijboer, Donald. No 126 Wing RCAF: Aviation Elite Units 35. Botley, UK: Osprey Publishing Limited, 2010. ISBN 978-1-84603-483-1
  • Payton-Smith, D. J. Oil: A Study of War-time Policy and Administration. London: Her Majesty's Stationery Office, 1971.
  • Price, Alfred. The Spitfire Story. London: Jane's Publishing Company, 1982. ISBN 0-86720-624-1.
  • Pugh, Peter. The Magic of a Name – The Rolls-Royce Story – The First 40 Years. Cambridge, England. Icon Books, 2000. ISBN 1-84046-151-9.
  • Robertson, Bruce. Spitfire: The Story of a Famous Fighter. Hemel Hempstead, Hertfordshire, UK: Model & Allied Publications, 1960. Third revised edition 1973. ISBN 0-900435-11-9.
  • Robotham, William Arthur. Silver Ghosts and Silver Dawn. London: Constable, 1970. ISBN 9780094566903
  • Rubbra, A.A. Rolls-Royce Piston Aero Engines: A Designer Remembers. Derby, England: Rolls-Royce Heritage Trust, 1990. ISBN 1-872922-00-7.
  • Simons, Graham M. Mosquito: The Original Multi-Role Combat Aircraft. Barnsley, Yorkshire UK: Pen & Sword Books, 2011. ISBN 978-1-84884-426-1
  • Smallwood, Hugh. Spitfire in Blue. London: Osprey Aerospace, 1996. ISBN 1-85532-615-9.
  • Smith, G. Geoffrey. "A British Masterpiece. (article and images)." Flight No. 1731, Volume XLI, 26 February 1942.
  • Smith, G. Geoffrey. "Rolls-Royce Merlin 'Sixty-One' (article and images)." Flight No. 1773, Volume XLII, 17 December 1942.
  • Tanner, John. The Spitfire V Manual (AP1565E reprint). London: Arms and Armour Press, 1981. ISBN 0-85368-420-0.
  • White, Graham. Allied Aircraft Piston Engines of World War II: History and Development of Frontline Aircraft Piston Engines Produced by Great Britain and the United States During World War II. Warrendale, Pennsylvania: SAE International, 1995. ISBN 1-56091-655-9
  • Wilkinson, Paul H. Aircraft Engines of the World 1946 (3rd ed.). London: Sir Isaac Pitman and Sons, 1946.
  • "Some Trends in engine design (article and images)." Flight No. 1563, Volume XXXIV, 8 December 1938.
  • "Rolls-Royce Merlin 130 Series (article and images)." Flight No. 1935, Volume XLIX, 24 January 1946.
  • "Two New Power Units (article and images)." Flight and The Aircraft Engineer No. 1961, Volume L, 25 July 1946.

Further reading edit

  • Gunston, Bill. Development of Piston Aero Engines. Cambridge: Patrick Stephens, 2006. ISBN 0-7509-4478-1
  • Henshaw, Alex. Sigh for a Merlin: Testing the Spitfire. London: Crecy, 1999 (2nd revised edition). ISBN 0-947554-83-1.
  • Jackson, Robert. The Encyclopedia of Military Aircraft Bath, UK: Parragon Books, 2006. ISBN 1-4054-2465-6.
  • Price, Alfred. Spitfire Mark I/II Aces 1939–41. London: Osprey Aerospace, 1996. ISBN 1-85532-627-2.
  • Quill, Jeffrey. "Spitfire: A Test Pilot's Story". London: John Murray, 1983; Crecy Publishing 1996 (2nd edition) ISBN 978-0-947554-72-9

External links edit

 
Wikimedia Commons has media related to Rolls-Royce Merlin.
  • Merlin engines in Manchester – BBC
  • Post-War Rolls-Royce film on manufacturing the Merlin – YouTube
  • Merlin 60 series comparison drawings – Spitfireperformance.com
  • Rolls-Royce Merlin 61 sectioned drawing
  • "Vee-Twelve Par Excellence" a 1937 Flight article on the Merlin I and II
  • "A British Masterpiece" a 1942 Flight article on the Merlin XX
  • "Universal Power Plants" – 1947 Flight article on postwar Merlin installations for civilian aircraft
  • Merlin engine photo gallery from BBC Radio Leicester
  • Sectioned image of possible turbocharger installation – Flight International
  • The Rolls-Royce Merlin – Aircraft Engines of The World

February 14, 2024
rolls, royce, merlin, packard, produced, licensed, version, packard, 1650, merlin, british, liquid, cooled, piston, aero, engine, litres, capacity, rolls, royce, designed, engine, first, 1933, private, venture, initially, known, later, called, merlin, followin. For the Packard produced licensed version see Packard V 1650 Merlin The Rolls Royce Merlin is a British liquid cooled V 12 piston aero engine of 27 litres 1 650 cu in capacity Rolls Royce designed the engine and first ran it in 1933 as a private venture Initially known as the PV 12 it was later called Merlin following the company convention of naming its four stroke piston aero engines after birds of prey MerlinThe Rolls Royce MerlinType Liquid cooled V 12 four stroke piston aero engineNational origin United KingdomManufacturer Rolls Royce LimitedFirst run 15 October 1933Major applications Avro Lancaster de Havilland Mosquito Handley Page Halifax Hawker HurricaneSupermarine SpitfireNumber built 149 659Variants Packard V 1650 MerlinDeveloped into Rolls Royce MeteorAfter several modifications the first production variants of the PV 12 were completed in 1936 The first operational aircraft to enter service using the Merlin were the Fairey Battle Hawker Hurricane and Supermarine Spitfire The Merlin remains most closely associated with the Spitfire and Hurricane although the majority of the production run was for the four engined Avro Lancaster heavy bomber A series of rapidly applied developments brought about by wartime needs markedly improved the engine s performance and durability Starting at 1 000 horsepower 750 kW for the first production models most late war versions produced just under 1 800 horsepower 1 300 kW and the very latest version as used in the de Havilland Hornet over 2 000 horsepower 1 500 kW One of the most successful aircraft engines of the World War II era some 50 versions of the Merlin were built by Rolls Royce in Derby Crewe and Glasgow as well as by Ford of Britain at their Trafford Park factory near Manchester A de rated version was also the basis of the Rolls Royce Rover Meteor tank engine Post war the Merlin was largely superseded by the Rolls Royce Griffon for military use with most Merlin variants being designed and built for airliners and military transport aircraft The Packard V 1650 was a version of the Merlin built in the United States Production ceased in 1950 after a total of almost 150 000 engines had been delivered Merlin engines remain in Royal Air Force service today with the Battle of Britain Memorial Flight and power many restored aircraft in private ownership worldwide Contents 1 Design and development 1 1 Origin 1 2 Development 1 2 1 Early engines 1 2 2 Production engines 1 2 3 Basic component overview Merlin 61 1 2 4 Technical improvements 1 2 4 1 Ejector exhausts 1 2 4 2 Supercharger 1 2 4 3 Carburettor developments 1 2 4 4 Improved fuels 2 Production 2 1 Derby 2 2 Crewe 2 3 Glasgow 2 4 Manchester 2 5 Packard V 1650 3 Variants 4 Applications 4 1 Postwar 4 2 Alternative applications 5 Surviving engines 6 Engines on display 7 Specifications Merlin 61 7 1 General characteristics 7 2 Components 7 3 Performance 8 See also 9 References 9 1 Footnotes 9 2 Citations 9 3 Bibliography 10 Further reading 11 External linksDesign and development editOrigin edit In the early 1930s Rolls Royce started planning its future aero engine development programme and realised there was a need for an engine larger than their 21 litre 1 296 cu in Kestrel which was being used with great success in a number of 1930s aircraft 1 Consequently work was started on a new 1 100 hp 820 kW class design known as the PV 12 with PV standing for Private Venture 12 cylinder as the company received no government funding for work on the project The PV 12 was first run on 15 October 1933 and first flew in a Hawker Hart biplane serial number K3036 on 21 February 1935 2 The engine was originally designed to use the evaporative cooling system then in vogue This proved unreliable and when ethylene glycol from the U S became available the engine was adapted to use a conventional liquid cooling system The Hart was subsequently delivered to Rolls Royce where as a Merlin testbed it completed over 100 hours of flying with the Merlin C and E engines 3 In 1935 the Air Ministry issued a specification F10 35 for new fighter aircraft with a minimum airspeed of 310 mph 500 km h Fortunately two designs had been developed the Supermarine Spitfire and the Hawker Hurricane the latter designed in response to another specification F36 34 4 Both were designed around the PV 12 instead of the Kestrel and were the only contemporary British fighters to have been so developed Production contracts for both aircraft were placed in 1936 and development of the PV 12 was given top priority as well as government funding Following the company convention of naming its piston aero engines after birds of prey Rolls Royce named the engine the Merlin after a small Northern Hemisphere falcon Falco columbarius nb 1 5 Two more Rolls Royce engines developed just prior to the war were added to the company s range The 885 hp 660 kW Rolls Royce Peregrine was an updated supercharged development of their V 12 Kestrel design while the 1 700 hp 1 300 kW 42 litre 2 560 cu in Rolls Royce Vulture used four Kestrel sized cylinder blocks fitted to a single crankcase and driving a common crankshaft forming an X 24 layout 6 This was to be used in larger aircraft such as the Avro Manchester 7 Although the Peregrine appeared to be a satisfactory design it was never allowed to mature since Rolls Royce s priority was refining the Merlin As a result the Peregrine saw use in only two aircraft the Westland Whirlwind fighter and one of the Gloster F 9 37 prototypes The Vulture was fitted to the Avro Manchester bomber but proved unreliable in service and the planned fighter using it the Hawker Tornado was cancelled as a result 8 With the Merlin itself soon pushing into the 1 500 hp 1 100 kW range the Peregrine and Vulture were both cancelled in 1943 and by mid 1943 the Merlin was supplemented in service by the larger Griffon 9 The Griffon incorporated several design improvements and ultimately superseded the Merlin Development edit Initially the new engine was plagued with problems such as failure of the accessory gear trains and coolant jackets Several different construction methods were tried before the basic design of the Merlin was set 10 Early production Merlins were unreliable common problems were cylinder head cracking coolant leaks and excessive wear to the camshafts and crankshaft main bearings 11 Early engines edit The prototype developmental and early production engine types were the PV 12The initial design using an evaporative cooling system Two built passed bench type testing in July 1934 generating 740 hp 550 kW at 12 000 foot 3 700 m equivalent First flown 21 February 1935 2 Merlin BTwo built ethylene glycol liquid cooling system introduced Ramp cylinder heads inlet valves were at a 45 degree angle to the cylinder Passed Type Testing February 1935 generating 950 hp 710 kW at 11 000 foot 3 400 m equivalent 2 Merlin CDevelopment of Merlin B crankcase and cylinder blocks became three separate castings with bolt on cylinder heads 2 First flight in Hawker Horsley 21 December 1935 950 hp 710 kW at 11 000 foot 3 400 m 12 Merlin ESimilar to C with minor design changes Passed 50 hour civil test in December 1935 generating a constant 955 hp 712 kW and a maximum rating of 1 045 hp 779 kW Failed military 100 hour test in March 1936 Powered the Supermarine Spitfire prototype 13 nbsp Parallel valve Merlin cylinder headMerlin F Merlin I Similar to C and E First flight in Horsley 16 July 1936 14 This became the first production engine and was designated as the Merlin I The Merlin continued with the ramp head but this was not a success and only 172 were made The Fairey Battle I was the first production aircraft to be powered by the Merlin I and first flew on 10 March 1936 13 Merlin G Merlin II Replaced ramp cylinder heads with parallel pattern heads valve stems parallel to the cylinder bore axis scaled up from the Kestrel engine 400 hour flight endurance tests carried out at RAE July 1937 acceptance test 22 September 1937 14 It was first widely delivered as the 1 030 hp 770 kW Merlin II in 1938 and production was quickly stepped up for Fairey Battle II 13 Merlin IIIMerlin II with standardised de Havilland Rotol SBAC propeller shaft and dual accessory drive 1 030 hp 770 kW at 3 000 rpm at 10 250 feet 3 120 m at 6 5 lb boost 15 Formed basis for the Rolls Royce Rover Meteor tank engine Racing MerlinRacing engine for 1937 38 Speed Spitfire world speed record attempt Merlin III with strengthened pistons connecting rods and gudgeon pins running on increased octane fuel developed 2 160 hp 1 610 kW at 3 200 rpm and 27 lb boost a power weight ratio of 0 621 lb per horsepower Completed 15 hour endurance run at 1 800 hp 1 300 kW 3 200 rpm at 22 lb boost 15 Merlin IVMerlin with pressure water cooling for Armstrong Whitworth Whitley IV Merlin VMerlin for Fairey Battle V Merlin VIIIMedium supercharged Merlin developed for Fairey Fulmar I rated 1 010 hp 750 kW at 2 850 rpm at 6 750 feet 2 060 m 1 080 hp 810 kW at 3 000 rpm for take off using 100 octane fuel 15 Merlin XFirst Merlin with two speed supercharger 1 145 hp 854 kW in low gear at 5 250 feet 1 600 m 1 010 hp 750 kW in high gear at 17 750 feet 5 410 m First of Rolls Royce unitised Power Plant installation designs for this engine in 1937 15 and used in Handley Page Halifax I Vickers Wellington II and Armstrong Whitworth Whitley V and VII Merlin XIIMerlin fitted with 0 477 1 reduction gear installed in some Spitfire II s with three bladed Rotol constant speed propeller Rated at 1 150 hp 860 kW at 3 000 rpm at 14 000 feet 4 300 m 15 Merlin XXMerlin X with Stanley Hooker re designed supercharger 16 incorporating re designed inlet and improved guide vanes on impeller with revised blower gear ratios 8 15 1 for low gear 9 49 1 for high gear New larger SU twin choke updraught carburettor Engine interchangeable with Merlin X Rated at 1 240 hp 920 kW at 2 850 rpm in low gear at 10 000 feet 3 000 m and 9 lb boost 1 175 hp 876 kW at 2 850 rpm in high gear at 17 500 feet 5 300 m at 9 lb boost Revised Rolls Royce unitised Power Plant installation design Engine used in Bristol Beaufighter II Boulton Paul Defiant II Handley Page Halifax II and V Hawker Hurricane II and IV and Avro Lancaster I and III First Merlin produced by Packard Motor Car Company as V 1650 1 and designated by Rolls Royce as Merlin 28 15 Production engines edit The Merlin II and III series were the first main production versions of the engine The Merlin III was the first version to incorporate a universal propeller shaft allowing either de Havilland or Rotol manufactured propellers to be used 17 The first major version to incorporate changes brought about through experience in operational service was the XX which was designed to run on 100 octane fuel nb 2 This fuel allowed higher manifold pressures which were achieved by increasing the boost from the centrifugal supercharger The Merlin XX also utilised the two speed superchargers designed by Rolls Royce resulting in increased power at higher altitudes than previous versions Another improvement introduced with the Merlin X was the use of a 70 30 water glycol coolant mix rather than the 100 glycol of the earlier versions This substantially improved engine life and reliability removed the fire hazard of the flammable ethylene glycol and reduced the oil leaks that had been a problem with the early Merlin I II and III series 19 The process of improvement continued with later versions running on higher octane ratings delivering more power Fundamental design changes were also made to all key components again increasing the engine s life and reliability By the end of the war the little engine was delivering over 1 600 hp 1 200 kW in common versions and as much as 2 030 hp 1 510 kW in the Merlin 130 131 versions specifically designed for the de Havilland Hornet 20 Ultimately during tests conducted by Rolls Royce at Derby an RM 17 SM the high altitude version of the Merlin 100 Series achieved 2 640 hp 1 970 kW at 36 lb boost 103 Hg on 150 octane fuel with water injection 21 With the end of the war work on improving Merlin power output was halted and the development effort was concentrated on civil derivatives of the Merlin 22 Development of what became the Transport Merlin TML 23 commenced with the Merlin 102 the first Merlin to complete the new civil type test requirements and was aimed at improving reliability and service overhaul periods for airline operators using airliner and transport aircraft such as the Avro Lancastrian Avro York Merlin 500 series Avro Tudor II amp IV Merlin 621 Tudor IVB amp V Merlin 623 TCA Canadair North Star Merlin 724 and BOAC Argonaut Merlin 724 IC 24 By 1951 the time between overhauls TBO was typically 650 800 hours depending on use 25 26 By then single stage engines had accumulated 2 615 000 engine hours in civil operation and two stage engines 1 169 000 27 In addition an exhaust system to reduce noise levels to below those from ejector exhausts was devised for the North Star Argonaut This cross over system took the exhaust flow from the inboard bank of cylinders up and over the engine before discharging the exhaust stream on the outboard side of the UPP nacelle As a result sound levels were reduced by between 5 and 8 decibels The modified exhaust also conferred an increase in horsepower over the unmodified system of 38 hp 28 kW resulting in a 5 knot improvement in true air speed Still air range of the aircraft was also improved by around 4 per cent 23 The modified engine was designated the TMO and the modified exhaust system was supplied as kit that could be installed on existing engines either by the operator or by Rolls Royce 23 Power ratings for the civil Merlin 600 620 and 621 series was 1 160 hp 870 kW continuous cruising at 23 500 feet 7 200 m and 1 725 hp 1 286 kW for take off Merlins 622 626 were rated at 1 420 hp 1 060 kW continuous cruising at 18 700 feet 5 700 m and 1 760 hp 1 310 kW for take off Engines were available with single stage two speed supercharging 500 series two stage two speed supercharging 600 series and with full intercooling or with half intercooling charge heating charge heating being employed for cold area use such as in Canada 24 Civil Merlin engines in airline service flew 7 818 000 air miles in 1946 17 455 000 in 1947 and 24 850 000 miles in 1948 28 Basic component overview Merlin 61 edit From Jane s 29 Cylinders Twelve cylinders consisting of high carbon steel liners set in two two piece cylinder blocks of cast R R 50 aluminium alloy having separate heads and skirts Wet liners ie coolant in direct contact with external face of liners Cylinder heads fitted with cast iron inlet valve guides phosphor bronze exhaust valve guides and renewable Silchrome steel alloy valve seats Two diametrically opposed spark plugs protrude into each combustion chamber Pistons Machined from R R 59 alloy forgings Fully floating hollow gudgeon pins of hardened nickel chrome steel Three compression and one oil control ring above the gudgeon pin and one oil control ring below Connecting rods H section machined nickel steel forgings each pair consisting of a plain and a forked rod The forked rod carries a nickel steel bearing block which accommodates steel backed lead bronze alloy bearing shells The small end of each rod houses a floating phosphor bronze bush Crankshaft One piece machined from a nitrogen hardened nickel chrome molybdenum steel forging Statically and dynamically balanced Seven main bearings and six throws Crankcase Two aluminium alloy castings joined together on the horizontal centreline The upper portion bears the wheelcase supercharger and accessories and carries the cylinder blocks crankshaft main bearings split mild steel shells lined with lead bronze alloy and part of the housing for the airscrew reduction gear The lower half forms an oil sump and carries the oil pumps and filters Wheelcase Aluminium casting fitted to rear of crankcase Houses drives to the camshafts magnetos coolant and oil pumps supercharger hand and electric starters and the electric generator Valve gear Two inlet and two exhaust poppet valves of K E 965 steel per cylinder Both the inlet and exhaust valves have hardened stellited ends while the exhaust valves also have sodium cooled stems and heads protected with a Brightray nickel chromium coating Each valve is kept closed by a pair of concentric coil springs A single seven bearing camshaft located on the top of each cylinder head operates 24 individual steel rockers 12 pivoting from a rocker shaft on the inner intake side of the head to actuate the exhaust valves the others pivoting from a shaft on the exhaust side of the head to actuate the inlet valves Technical improvements edit Most of the Merlin s technical improvements resulted from more efficient superchargers designed by Stanley Hooker and the introduction of aviation fuel with increased octane ratings Numerous detail changes were made internally and externally to the engine to withstand increased power ratings and to incorporate advances in engineering practices 30 Ejector exhausts edit nbsp Merlin 55 ejector exhaust detail Spitfire LF VB EP120The Merlin consumed an enormous volume of air at full power equivalent to the volume of a single decker bus per minute and with the exhaust gases exiting at 1 300 mph 2 100 km h it was realised that useful thrust could be gained simply by angling the gases backwards instead of venting sideways During tests 70 pounds force 310 N 32 kgf thrust at 300 mph 480 km h or roughly 70 hp 52 kW was obtained which increased the level maximum speed of the Spitfire by 10 mph 16 km h to 360 mph 580 km h 31 The first versions of the ejector exhausts featured round outlets while subsequent versions of the system used fishtail style outlets which marginally increased thrust and reduced exhaust glare for night flying In September 1937 the Spitfire prototype K5054 was fitted with ejector type exhausts Later marks of the Spitfire used a variation of this exhaust system fitted with forward facing intake ducts to distribute hot air out to the wing mounted guns to prevent freezing and stoppages at high altitudes replacing an earlier system that used heated air from the engine coolant radiator The latter system had become ineffective due to improvements to the Merlin itself which allowed higher operating altitudes where air temperatures are lower 32 Ejector exhausts were also fitted to other Merlin powered aircraft Supercharger edit Central to the success of the Merlin was the supercharger A C Lovesey an engineer who was a key figure in the design of the Merlin delivered a lecture on the development of the Merlin in 1946 in this extract he explained the importance of the supercharger The impression still prevails that the static capacity known as the swept volume is the basis of comparison of the possible power output for different types of engine but this is not the case because the output of the engine depends solely on the mass of air it can be made to consume efficiently and in this respect the supercharger plays the most important role the engine has to be capable of dealing with the greater mass flows with respect to cooling freedom from detonation and capable of withstanding high gas and inertia loads During the course of research and development on superchargers it became apparent to us that any further increase in the altitude performance of the Merlin engine necessitated the employment of a two stage supercharger 33 As the Merlin evolved so too did the supercharger the latter fitting into three broad categories 34 Single stage single speed gearbox Merlin I to III XII 30 40 and 50 series 1937 1942 nb 3 Single stage two speed gearbox experimental Merlin X 1938 production Merlin XX 1940 1945 Two stage two speed gearbox with intercooler mainly Merlin 60 70 and 80 series 1942 1946 The Merlin supercharger was originally designed to allow the engine to generate maximum power at an altitude of about 16 000 ft 4 900 m In 1938 Stanley Hooker an Oxford graduate in applied mathematics explained I soon became very familiar with the construction of the Merlin supercharger and carburettor Since the supercharger was at the rear of the engine it had come in for pretty severe design treatment and the air intake duct to the impeller looked very squashed Tests conducted by Hooker showed the original intake design was inefficient limiting the performance of the supercharger 35 nb 4 Hooker subsequently designed a new air intake duct with improved flow characteristics which increased maximum power at a higher altitude of over 19 000 ft 5 800 m and also improved the design of both the impeller and the diffuser which controlled the airflow to it These modifications led to the development of the single stage Merlin XX and 45 series 36 A significant advance in supercharger design was the incorporation in 1938 of a two speed drive designed by the French company Farman to the impeller of the Merlin X 37 nb 5 The later Merlin XX incorporated the two speed drive as well as several improvements that enabled the production rate of Merlins to be increased 39 The low ratio gear which operated from takeoff to an altitude of 10 000 ft 3 000 m drove the impeller at 21 597 rpm and developed 1 240 hp 920 kW at that height while the high gear s 25 148 rpm power rating was 1 175 hp 876 kW at 18 000 ft 5 500 m These figures were achieved at 2 850 rpm engine speed using 9 pounds per square inch 1 66 atm 48 boost 40 In 1940 after receiving a request in March of that year from the Ministry of Aircraft Production for a high rated 40 000 ft 12 000 m Merlin for use as an alternative engine to the turbocharged Hercules VIII used in the prototype high altitude Vickers Wellington V bomber Rolls Royce started experiments on the design of a two stage supercharger and an engine fitted with this was bench tested in April 1941 eventually becoming the Merlin 60 41 The basic design used a modified Vulture supercharger for the first stage while a Merlin 46 supercharger was used for the second 42 A liquid cooled intercooler on top of the supercharger casing was used to prevent the compressed air fuel mixture from becoming too hot nb 6 Also considered was an exhaust driven turbocharger but although a lower fuel consumption was an advantage the added weight and the need to add extra ducting for the exhaust flow and waste gates meant that this option was rejected in favour of the two stage supercharger 43 Fitted with the two stage two speed supercharger the Merlin 60 series gained 300 hp 220 kW at 30 000 ft 9 100 m over the Merlin 45 series 42 at which altitude a Spitfire IX was nearly 70 mph 110 km h faster than a Spitfire V 44 The two stage Merlin family was extended in 1943 with the Merlin 66 which had its supercharger geared for increased power ratings at low altitudes and the Merlin 70 series that were designed to deliver increased power at high altitudes 45 While the design of the two stage supercharger forged ahead Rolls Royce also continued to develop the single stage supercharger resulting in 1942 in the development of a smaller cropped impeller for the Merlin 45M and 55M both of these engines developed greater power at low altitudes 46 In squadron service the LF V variant of the Spitfire fitted with these engines became known as the clipped clapped and cropped Spitty to indicate the shortened wingspan the less than perfect condition of the used airframes and the cropped supercharger impeller 47 Carburettor developments edit nbsp Preserved Merlin 63 showing intercooler radiator supercharger and carburettorThe use of carburettors was calculated to give a higher specific power output due to the lower temperature hence greater density of the fuel air mixture compared to injected systems 48 However the Merlin s float controlled carburettor meant that if Spitfires or Hurricanes were to pitch nose down into a steep dive negative g force g produced temporary fuel starvation causing the engine to cut out momentarily By comparison the contemporary Bf 109E which had direct fuel injection could bunt straight into a high power dive to escape attack RAF fighter pilots soon learned to avoid this with a half roll of their aircraft before diving in pursuit 49 A restrictor in the fuel supply line together with a diaphragm fitted in the float chamber jocularly nicknamed Miss Shilling s orifice nb 7 after its inventor went some way towards curing fuel starvation in a dive by containing fuel under negative G however at less than maximum power a fuel rich mixture still resulted Another improvement was made by moving the fuel outlet from the bottom of the S U carburettor to exactly halfway up the side which allowed the fuel to flow equally well under negative or positive g 50 Further improvements were introduced throughout the Merlin range 1943 saw the introduction of a Bendix Stromberg pressure carburettor that injected fuel at 5 pounds per square inch 34 kPa 0 34 bar through a nozzle directly into the supercharger and was fitted to Merlin 66 70 76 77 and 85 variants The final development which was fitted to the 100 series Merlins was an S U injection carburettor that injected fuel into the supercharger using a fuel pump driven as a function of crankshaft speed and engine pressures 51 Improved fuels edit nbsp Page from Pilot s Notes Merlin II III and V A P 1590B explaining the use of 12lbs boost and 100 Octane fuel At the start of the war the Merlin I II and III ran on the then standard 87 octane aviation spirit and could generate just over 1 000 hp 750 kW from its 27 litre 1 650 cu in displacement the maximum boost pressure at which the engine could be run using 87 octane fuel was 6 pounds per square inch 141 kPa 1 44 atm nb 8 However as early as 1938 at the 16th Paris Air Show Rolls Royce displayed two versions of the Merlin rated to use 100 octane fuel The Merlin R M 2M was capable of 1 265 hp 943 kW at 7 870 feet 2 400 m 1 285 hp 958 kW at 9 180 feet 2 800 m and 1 320 hp 980 kW on take off while a Merlin X with a two speed supercharger in high gear generated 1 150 hp 860 kW at 15 400 feet 4 700 m and 1 160 hp 870 kW at 16 730 feet 5 100 m 52 From late 1939 100 octane fuel became available from the U S West Indies Persia and in smaller quantities domestically 53 consequently in the first half of 1940 the RAF transferred all Hurricane and Spitfire squadrons to 100 octane fuel 54 Small modifications were made to Merlin II and III series engines allowing an increased emergency boost pressure of 12 pounds per square inch 183 kPa 1 85 atm At this power setting these engines were able to produce 1 310 hp 980 kW at 9 000 ft 2 700 m while running at 3 000 revolutions per minute 55 56 Increased boost could be used indefinitely as there was no mechanical time limit mechanism but pilots were advised not to use increased boost for more than a maximum of five minutes and it was considered a definite overload condition on the engine if the pilot resorted to emergency boost he had to report this on landing when it was noted in the engine log book while the engineering officer was required to examine the engine and reset the throttle gate 57 Later versions of the Merlin ran only on 100 octane fuel and the five minute combat limitation was raised to 18 pounds per square inch 224 kPa 2 3 atm 58 In late 1943 trials were run of a new 100 150 grade 150 octane fuel recognised by its bright green colour and awful smell 59 Initial tests were conducted using 6 5 cubic centimetres 0 23 imp fl oz of tetraethyllead T E L for every one imperial gallon of 100 octane fuel or 1 43 cc L or 0 18 U S fl oz U S gal but this mixture resulted in a build up of lead in the combustion chambers causing excessive fouling of the spark plugs Better results were achieved by adding 2 5 mono methyl aniline M M A to 100 octane fuel 60 The new fuel allowed the five minute boost rating of the Merlin 66 to be raised to 25 pounds per square inch 272 kPa 2 7 atm 61 With this boost rating the Merlin 66 generated 2 000 hp 1 500 kW at sea level and 1 860 hp 1 390 kW at 10 500 ft 3 200 m 62 Starting in March 1944 the Merlin 66 powered Spitfire IXs of two Air Defence of Great Britain ADGB squadrons were cleared to use the new fuel for operational trials and it was put to good use in the summer of 1944 when it enabled Spitfire L F Mk IXs to intercept V 1 flying bombs coming in at low altitudes 61 100 150 grade fuel was also used by Mosquito night fighters of the ADGB to intercept V 1s 63 In early February 1945 Spitfires of the Second Tactical Air Force 2TAF also began using 100 150 grade fuel 64 nb 9 This fuel was also offered to the USAAF where it was designated PPF 44 1 and informally known as Pep 66 Production editProduction of the Rolls Royce Merlin was driven by the forethought and determination of Ernest Hives who at times was enraged by the apparent complacency and lack of urgency encountered in his frequent correspondence with the Air Ministry the Ministry of Aircraft Production and local authority officials 67 Hives was an advocate of shadow factories and sensing the imminent outbreak of war pressed ahead with plans to produce the Merlin in sufficient numbers for the rapidly expanding Royal Air Force 68 Despite the importance of uninterrupted production several factories were affected by industrial action 69 By the end of its production run in 1950 168 176 Merlin engines had been built over 112 000 in Britain and more than 55 000 under licence in the U S nb 10 56 nb 11 Derby edit nbsp The Marble Hall at the Rolls Royce factory Nightingale Road Derby photo 2005 The existing Rolls Royce facilities at Osmaston Derby were not suitable for mass engine production although the floor space had been increased by some 25 between 1935 and 1939 Hives planned to build the first two or three hundred engines there until engineering teething troubles had been resolved To fund this expansion the Air Ministry had provided a total of 1 927 000 by December 1939 72 nb 12 Having a workforce that consisted mainly of design engineers and highly skilled men the Derby factory carried out the majority of development work on the Merlin with flight testing carried out at nearby RAF Hucknall All the Merlin engined aircraft taking part in the Battle of Britain had their engines assembled in the Derby factory Total Merlin production at Derby was 32 377 74 The original factory closed in March 2008 but the company maintains a presence in Derby 75 Crewe edit To meet the increasing demand for Merlin engines Rolls Royce started building work on a new factory at Crewe in May 1938 with engines leaving the factory in 1939 The Crewe factory had convenient road and rail links to their existing facilities at Derby Production at Crewe was originally planned to use unskilled labour and sub contractors with which Hives felt there would be no particular difficulty but the number of required sub contracted parts such as crankshafts camshafts and cylinder liners eventually fell short and the factory was expanded to manufacture these parts in house 76 Initially the local authority promised to build 1 000 new houses to accommodate the workforce by the end of 1938 but by February 1939 it had only awarded a contract for 100 Hives was incensed by this complacency and threatened to move the whole operation but timely intervention by the Air Ministry improved the situation In 1940 a strike took place when women replaced men on capstan lathes the workers union insisting this was a skilled labour job however the men returned to work after 10 days 77 Total Merlin production at Crewe was 26 065 74 The factory was used postwar for the production of Rolls Royce and Bentley motor cars and military fighting vehicle power plants In 1998 Volkswagen AG bought the Bentley marque and the factory Today it is known as Bentley Crewe 78 Glasgow edit nbsp Workers assembling cylinder heads on the Hillington Merlin production line in 1942Hives further recommended that a factory be built near Glasgow to take advantage of the abundant local work force and the supply of steel and forgings from Scottish manufacturers In September 1939 the Air Ministry allocated 4 500 000 for a new Shadow factory 79 nb 13 This government funded and operated factory was built at Hillington starting in June 1939 with workers moving into the premises in October one month after the outbreak of war The factory was fully occupied by September 1940 A housing crisis also occurred at Glasgow where Hives again asked the Air Ministry to step in 81 With 16 000 employees the Glasgow factory was one of the largest industrial operations in Scotland Unlike the Derby and Crewe plants which relied significantly on external subcontractors it produced almost all the Merlin s components itself 82 Hillingdon required a great deal of attention from Hives from when it was producing its first complete engine it had the highest proportion of unskilled workers in any Rolls Royce managed factory 83 Engines began to leave the production line in November 1940 and by June 1941 monthly output had reached 200 increasing to more than 400 per month by March 1942 84 In total 23 675 engines were produced Worker absenteeism became a problem after some months due to the physical and mental effects of wartime conditions such as the frequent occupation of air raid shelters It was agreed to cut the punishing working hours slightly to 82 hours a week with one half Sunday per month awarded as holiday 85 Record production is reported to have been 100 engines in one day 86 Immediately after the war the site repaired and overhauled Merlin and Griffon engines and continued to manufacture spare parts 86 Finally following the production of the Rolls Royce Avon turbojet and others the factory was closed in 2005 87 Manchester edit Main article Ford Trafford Park Factory The Ford Motor Company was asked to produce Merlins at Trafford Park Stretford near Manchester and building work on a new factory was started in May 1940 on a 118 acre 48 ha site Built with two distinct sections to minimise potential bomb damage it was completed in May 1941 and bombed in the same month nb 14 At first the factory had difficulty in attracting suitable labour and large numbers of women youths and untrained men had to be taken on Despite this the first Merlin engine came off the production line one month later and it was building the engine at a rate of 200 per week by 1943 88 at which point the joint factories were producing 18 000 Merlins per year 34 In his autobiography Not much of an Engineer Sir Stanley Hooker states once the great Ford factory at Manchester started production Merlins came out like shelling peas 89 Some 17 316 people worked at the Trafford Park plant including 7 260 women and two resident doctors and nurses 88 Merlin production started to run down in August 1945 and finally ceased on 23 March 1946 90 Total Merlin production at Trafford Park was 30 428 74 Packard V 1650 edit Main article Packard V 1650 Merlin As the Merlin was considered to be so important to the war effort negotiations were started to establish an alternative production line outside the UK Rolls Royce staff visited North American automobile manufacturers to select one to build the Merlin in the U S or Canada Henry Ford rescinded an initial offer to build the engine in the U S in July 1940 and the Packard Motor Car Company was selected to take on the 130 000 000 Merlin order equivalent to 2 72 billion in 2022 dollars 91 92 Agreement was reached in September 1940 and the first Packard built engine a Merlin XX designated the V 1650 1 ran in August 1941 93 Total Merlin production by Packard was 55 523 74 Six development engines were also made by Continental Motors Inc 74 Variants editMain article List of Rolls Royce Merlin variants This is a list of representative Merlin variants describing some of the mechanical changes made during development of the Merlin Engines of the same power output were typically assigned different model numbers based on supercharger or propeller gear ratios differences in cooling system or carburettors engine block construction or arrangement of engine controls 94 Power ratings quoted are usually maximum military power All but the Merlin 131 and 134 engines were right hand tractor i e the propeller rotated clockwise when viewed from the rear In addition to the mark numbers Merlin engines were allocated experimental numbers by the Ministry of Supply MoS e g RM 8SM for the Merlin 61 and some variants while under development these numbers are noted where possible 95 Merlin engines used in Spitfires apart from the Merlin 61 used a propeller reduction ratio of 477 1 Merlins used in bombers and other fighters used a ratio of 42 1 96 Data from Bridgman Jane s 97 unless otherwise noted Merlin II RM 1S 1 030 hp 770 kW at 3 000 rpm at 5 500 ft 1 676 m using 6 psi boost 41 kPa gauge or an absolute pressure of 144 kPa or 1 41 atm used 100 glycol coolant First production Merlin II delivered 10 August 1937 14 Merlin II used in the Boulton Paul Defiant Hawker Hurricane Mk I Supermarine Spitfire Mk I fighters and Fairey Battle light bomber 98 Merlin III RM 1S Merlin III fitted with universal propeller shaft able to mount either de Havilland or Rotol propellers 99 From late 1939 using 100 octane fuel and 12 psi boost 83 kPa gauge or an absolute pressure of 184 kPa or 1 82 atm the Merlin III developed 1 310 hp 980 kW at 3 000 rpm at 9 000 ft 2 700 m 55 using 87 octane fuel the power ratings were the same as the Merlin II Used in the Defiant Hurricane Mk I Spitfire Mk I fighters and Battle light bomber 98 First production Merlin III delivered 1 July 1938 14 Merlin X RM 1SM 1 130 hp 840 kW at 3 000 rpm at 5 250 ft 1 600 m maximum boost pressure 10 psi this was the first production Merlin to use a two speed supercharger Used in Halifax Mk I Wellington Mk II and Whitley Mk V bombers First production Merlin X 5 December 1938 14 Merlin XII RM 3S 1 150 hp 860 kW fitted with Coffman engine starter first version to use 70 30 water glycol coolant rather than 100 glycol Reinforced construction able to use constant boost pressure of up to 12 psi using 100 octane fuel Used in Spitfire Mk II 99 First production Merlin XII 2 September 1939 14 nbsp Preserved Merlin XX at the Royal Air Force Museum London Merlin XX RM 3SM 1 480 hp 1 100 kW at 3 000 rpm at 6 000 ft 1 829 m two speed supercharger boost pressure of up to 14 psi Used in Hurricane Mk II Beaufighter Mk II Halifax Mk II and Lancaster Mk I bombers and in the Spitfire Mk III prototypes N3297 amp W3237 100 First production Merlin XX 4 July 1940 14 nb 15 Merlin 32 RM 5M 1 645 hp 1 227 kW at 3 000 rpm at 2 500 ft 762 m a low altitude version of Merlin with cropped supercharger impellers for increased power at lower altitudes and a maximum boost pressure of 18 psi fitted with Coffman engine starter used mainly in Fleet Air Arm aircraft mainly the Fairey Barracuda Mk II torpedo bomber and Supermarine Seafire F Mk IIc fighters Also Hurricane Mk V and Spitfire P R Mk XIII 99 First production Merlin 32 17 June 1942 14 Merlin 45 RM 5S 1 515 hp 1 130 kW at 3 000 rpm at 11 000 ft 3 353 m used in Spitfire Mk V PR Mk IV and PR Mk VII Seafire Ib and IIc Maximum boost pressure of 16 psi First production Merlin 45 13 January 1941 14 Merlin 47 RM 6S 1 415 hp 1 055 kW at 3 000 rpm at 14 000 ft 4 267 m high altitude version used in Spitfire H F Mk VI Adapted with a Marshall compressor often called a blower to pressurise the cockpit First production Merlin 47 2 December 1941 14 Merlin 50 M RM 5S 1 585 hp 1 182 kW at 3 000 rpm at 3 800 ft 1 158 m low altitude version with supercharger impeller cropped to 9 5 in 241 mm in diameter Permitted boost was 18 psi 125 kPa gauge or an absolute pressure of 225 kPa or 2 2 atm instead of 16 psi 110 kPa gauge or an absolute pressure of 210 kPa or 2 08 atm on a normal Merlin 50 engine 101 102 Merlin 50 series was first to use the Bendix Stromberg negative g carburettor 103 Merlin 61 RM 8SM 1 565 hp 1 167 kW at 3 000 rpm at 12 250 ft 3 734 m 1 390 hp 1 040 kW at 3 000 rpm at 23 500 ft 7 163 m fitted with a new two speed two stage supercharger providing increased power at medium to high altitudes 15 psi boost used in Spitfire F Mk IX and P R Mk XI 104 First British production variant to incorporate two piece cylinder blocks designed by Rolls Royce for the Packard Merlin 105 Reduction gear ratio 42 1 with gears for pressurisation pump 106 First production Merlin 61 2 March 1942 14 Merlin 63 amp 63A1 710 hp 1 280 kW at 3 000 rpm at 8 500 ft 2 591 m 1 505 hp 1 122 kW at 3 000 rpm at 21 000 ft 6 401 m strengthened two speed two stage development of Merlin 61 18 psi boost Reduction gear ratio 477 1 Merlin 63A did not have extra gears for pressurisation and incorporated a strengthened supercharger drive quill shaft 107 Used in Spitfire F Mk VIII and F Mk IX 101 source source Audio of RR Merlin 66 266 starting Merlin 66 RM 10SM 1 720 hp 1 280 kW at 5 790 ft 1 765 m using 18 psi boost 124 kPa gauge or an absolute pressure of 225 kPa or 2 2 atm low altitude version of Merlin 63A Fitted with a Bendix Stromberg anti g carburettor 108 intercooler used a separate header tank 109 Used in Spitfire L F Mk VIII and L F Mk IX 101 Merlin 76 77 RM 16SM 43 1 233 hp 919 kW at 35 000 ft 10 668 m 43 Fitted with a two speed two stage supercharger and a Bendix Stromberg carburettor Dedicated high altitude version used in the Westland Welkin high altitude fighter and some later Spitfire and de Havilland Mosquito variants The odd numbered mark drove a Marshall Roots type blower for cockpit pressurising Merlin 130 1312 060 hp 1 540 kW redesigned slimline versions for the de Havilland Hornet Engine design modified to decrease frontal area to a minimum and was the first Merlin series to use down draught induction systems Coolant pump moved from the bottom of the engine to the starboard side Two speed two stage supercharger and S U injection carburettor Corliss throttle Maximum boost was 25 psi 170 kPa gauge or an absolute pressure of 270 kPa or 2 7 atm On the Hornet the Merlin 130 was fitted in the port nacelle the Merlin 131 fitted in the starboard nacelle was converted to a reverse or left hand tractor engine using an additional idler gear in the reduction gear casing 110 Merlin 133 1342 030 hp 1 510 kW derated for use at low altitude 130 131 variants used in Sea Hornet F Mk 20 N F Mk 21 and P R Mk 22 Maximum boost was lowered to 18 psi gauge 230 kPa or 2 2 atm absolute Merlin 266 RM 10SM The prefix 2 indicates engines built by Packard otherwise as Merlin 66 optimised for low altitude operation Fitted to the Spitfire Mk XVI 101 Merlin 6201 175 hp 876 kW continuous cruising using 2 650 rpm at 9 psi boost 62 kPa gauge or an absolute pressure of 165 kPa or 1 6 atm capable of emergency rating of 1 795 hp 1 339 kW at 3 000 rpm using 20 psi boost 138 kPa gauge or an absolute pressure of 241 kPa or 2 4 atm civilian engine developed from Merlin 102 two stage supercharger optimised for medium altitudes and used an S U injection carburettor Universal Power Plant UPP standardised annular radiator installation development of that used on Lancaster VI and Avro Lincoln The Merlin 620 621 series was designed to operate in the severe climatic conditions encountered on Canadian and long range North Atlantic air routes Used in Avro Tudor Avro York and the Canadair North Star 111 Applications editIn chronological order the first operational aircraft powered by the Merlin to enter service were the Fairey Battle Hawker Hurricane and Supermarine Spitfire 112 Although the engine is most closely associated with the Spitfire the four engined Avro Lancaster was the most numerous application followed by the twin engined de Havilland Mosquito 113 List from Lumsden 2003 114 nb 16 Armstrong Whitworth Whitley Avro Athena Avro Lancaster Avro Lancastrian Avro Lincoln Avro Manchester III Avro Tudor Avro York Boulton Paul Balliol and Sea Balliol Boulton Paul Defiant Bristol Beaufighter II CAC CA 18 Mark 23 Mustang Canadair North Star CASA 2 111B and D Cierva Air Horse de Havilland Mosquito de Havilland Hornet Fairey Barracuda Fairey Battle Fairey Fulmar Fairey P 4 34 Fiat G 59 Handley Page Halifax Handley Page Halton Hawker Hart Test bed Hawker Henley Hawker Horsley Test bed Hawker Hotspur Hawker Hurricane and Sea Hurricane Hispano Aviacion HA 1112 I Ae 30 Nancu Miles M 20 North American Mustang Mk X Renard R 38 Short Sturgeon Supermarine Type 322 Supermarine Seafire Supermarine Spitfire Tsunami Racer Vickers F 7 41 Vickers Wellington Mk II and Mk VI Vickers Windsor Westland Welkin nbsp Avro Lancaster B I powered by four Merlin XXs nbsp The slimline Merlin 130 131 series were designed for the de Havilland Hornet nbsp The Merlin 76 powered Vickers F 7 41Postwar edit At the end of World War II new versions of the Merlin the 600 and 700 series were designed and produced for use in commercial airliners such as the Avro Tudor military transport aircraft such as the Avro York and the Canadair North Star which performed in both roles These engines were basically military specification with some minor changes to suit the different operating environment 115 A Spanish built version of the Messerschmitt Bf 109 G 2 the 1954 Hispano Aviacion HA 1112 M1L Buchon was built in Hispano s factory in Seville with the Rolls Royce Merlin 500 45 engine of 1 600 horsepower 1 200 kW a fitting powerplant for the last produced version of the famous Messerschmitt fighter as the Bf 109 V1 prototype aircraft had been powered by the Rolls Royce Kestrel V 12 engine in 1935 116 The CASA 2 111 was another Spanish built version of a German aircraft the Heinkel He 111 that was adapted to use the Merlin after the supply of Junkers Jumo 211F 2 engines ran out at the end of the war 117 A similar situation existed with the Fiat G 59 when available stocks of the Italian licence built version of the Daimler Benz DB 605 engine ran short 118 The Australian built Avro Lincoln from A73 51 used Australian built Commonwealth Aircraft Corporation Merlin 102s A total of 108 CAC Merlins were built by the time production ended Alternative applications edit Further information Rolls Royce Merlin alternative uses A non supercharged version of the Merlin using a larger proportion of steel and iron components was produced for use in tanks This engine the Rolls Royce Meteor in turn led to the smaller Rolls Royce Meteorite 119 In 1943 further Meteor development was handed over to Rover in exchange for Rover s gas turbine interests 120 In 1938 Rolls Royce started work on modifying some Merlins which were later to be used in British MTBs MGBs and RAF Air Sea Rescue Launches For these the superchargers were modified single stage units and the engine was re engineered for use in a marine environment Some 70 engines were converted before priority was given to producing aero engines 121 Experiments were carried out by the Irish Army involving replacing the Bedford engine of a Churchill tank with a Rolls Royce Merlin engine salvaged from an Irish Air Corps Seafire aircraft The experiment was not a success although the reasons are not recorded 122 Surviving engines editOne of the most successful of the World War II era aircraft engines the Merlin continues to be used in many restored World War II vintage aircraft all over the world The Royal Air Force Battle of Britain Memorial Flight is a notable current operator of the Merlin In England the Shuttleworth Collection owns and operates a Merlin powered Hawker Sea Hurricane IB and a Supermarine Spitfire VC Both can be seen flying at home displays throughout the summer months 123 124 Engines on display edit source source source source Merlin24 ground demonstrationPreserved examples of the Rolls Royce Merlin are on display at the following museums Atlantic Canada Aviation Museum 125 Aviation Heritage Museum Western Australia 126 City of Norwich Aviation Museum in Horsham St Faith Norfolk 127 Montrose Air Station Heritage Centre 128 Polish Aviation Museum Krakow Cracow Poland 129 Rolls Royce Heritage Centre Derby several versions including displayed superchargers reduction gears and other components 130 Royal Air Force Museum Cosford amp London 131 Science Museum London 132 Shuttleworth Collection 133 Smithsonian Air and Space Museum Washington DC 134 Wings Museum West Sussex England 135 Specifications Merlin 61 edit nbsp Rolls Royce Merlin with components labelledData from Jane s 136 General characteristics Type 12 cylinder supercharged liquid cooled 60 Vee SOHC piston aircraft engine Bore 5 4 in 137 mm Stroke 6 0 in 152 mm Displacement 1 649 cu in 27 L Length 88 7 in 225 cm Width 30 8 in 78 cm Height 40 in 102 cm Dry weight 1 640 lb 744 kg nb 17 Components Valvetrain Overhead camshaft two intake and two exhaust valves per cylinder sodium cooled exhaust valve stems Supercharger Two speed two stage Boost pressure automatically linked to the throttle coolant air aftercooler between the second stage and the engine Fuel system Twin choke updraught Rolls Royce S U carburettor with automatic mixture control Twin independent fuel pumps Fuel type 100 130 Octane petrol Oil system Dry sump with one pressure pump and two scavenge pumps Cooling system 70 water and 30 ethylene glycol coolant mixture pressurised Supercharger intercooler system entirely separate from main cooling system 105 Reduction gear 0 42 1Performance Power output 1 290 hp 960 kW at 3 000 rpm at take off 1 565 hp 1 167 kW at 3 000 rpm at 12 250 ft 3 730 m MS gear nb 18 1 580 hp 1 180 kW at 3 000 rpm at 23 500 ft 7 200 m FS gear Specific power 0 96 hp cu in 43 6 kW L Compression ratio 6 1 Fuel consumption Minimum 30 Imp gal h 136 L h maximum 130 Imp gal h 591 L h nb 19 Power to weight ratio 0 96 hp lb 1 58 kW kg at maximum power See also editRolls Royce aircraft piston engines Rolls Royce Merlin alternative usesRelated development Packard V 1650 Merlin Rolls Royce Griffon Rolls Royce Meteor Tank engine developed from the Merlin Rolls Royce Meteorite cut down Meteor Comparable engines Allison V 1710 Daimler Benz DB 601 Hispano Suiza 12Y Junkers Jumo 213 Klimov VK 107 Mikulin AM 35Related lists List of aircraft engines List of Rolls Royce Merlin variantsReferences editFootnotes edit The naming tradition was started by managing director Claude Johnson in 1915 with the Eagle Hawk and Falcon engines There is no connection to King Arthur s legendary magician The Merlin II and III series were originally designed to use 87 octane fuel and later modified to allow the use of 100 octane fuel 18 Because of an accelerated design process the timelines of Merlin development overlapped for example the two stage supercharger was being designed before there was a need to introduce the modified Merlin 45M and 55Ms to counteract the threat of the Focke Wulf Fw 190 The function of the supercharger is to compress the fuel air mixture entering the engine cylinders any pressure loss to the impeller also called the rotor would impair the supercharger s efficiency Rolls Royce took out a licence in 1938 to build the two speed drive 38 A hot mixture could either pre ignite before reaching the engine s cylinders or detonate in the engine Invented in March 1941 by Beatrice Shilling an engineer at the Royal Aircraft Establishment Farnborough The British measured boost pressure as lbf sq in or psi and commonly referred to it as pounds of boost The normal atmospheric pressure at sea level is 14 5 psi 1 000 mbar thus a reading of 6 means that the air fuel mix is being compressed by a supercharger blower to 20 5 psi before entering the engine 25 means that the air fuel mix is now being compressed to 39 5 psi Monty Berger Senior Intelligence Officer of 126 RCAF Spitfire Wing 2 TAF alleged that there were still problems being experienced with the new fuel on his wing which was mistrusted by many pilots in the Wing 64 However another source states that the transition to 150 Grade went without problems 65 Factory production numbers Rolls Royce Derby 32 377 Rolls Royce Crewe 26 065 Rolls Royce Glasgow 23 675 Ford Manchester 30 428 Packard Motor Corp 55 523 37 143 Merlins 18 380 V 1650s Commonwealth Aircraft Corp CAC NSW Australia 108 Type MK102 1946 1952 for the CAC Avro Lincoln 70 Overall 168 176 Cost 2 000 engine 350 propeller 71 The Crewe works in fact had been leased to Rolls Royce by the government 73 This allocation had increased to 5 995 000 by December 1939 80 The new factory was bombed by the Luftwaffe in May 1941 88 In August 1940 drawings of the Merlin XX were sent to the Packard Motor Car Company and used as the basis for the Packard Merlin 28 14 Lumsden covers British aircraft only the Merlin may not be the main powerplant for these types for example one or two Hawker Harts and Horsleys were used to test early versions of the Merlin Plus 2 5 tolerance MS and FS refer to the supercharger blower speeds Moderate Fully Supercharged Moderate Supercharging referred to low to medium altitudes operation Full Supercharging to medium to high altitude operation 137 Ref A P 1565 I P amp L Pilot s Notes for Spitfire IX XI and XVI fuel consumption dependent on throttle mixture and boost settings plus altitude Citations edit Rubbra 1990 p 64 a b c d Lumsden 2003 p 203 Mason 1991 p 168 McKinstry 2007 p 53 Gunston 1989 p 137 Rubbra 1990 p 139 Lumsden 2003 pp 198 200 Lumsden 2003 p 200 Rubbra 1990 p 118 Rubbra 1990 pp 64 117 Rubbra 1990 pp 82 92 Morgan and Shacklady 2000 p 607 a b c Lumsden 2003 p 204 a b c d e f g h i j k l Morgan and Shacklady 2000 p 610 a b c d e f King H F 7 May 1954 The Two Rs Flight p 577 Archived from the original on 11 February 2017 Retrieved 22 August 2017 World Encyclopedia of Aero Engines 5th edition by Bill Gunston Sutton Publishing 2006 p 190 Fozard 1991 p 125 Air Ministry 1940 pp 6 10 Fozard 1991 pp 127 165 Flight January 1946 p 93 Lovesey 1946 p 223 Lovesey 1946 p 224 a b c Quieter Argonaut Flight 29 February 1952 p 242 Archived from the original on 31 January 2018 Retrieved 22 August 2017 a b King H F 7 May 1954 The Two Rs Flight p 579 Archived from the original on 11 February 2017 Retrieved 22 August 2017 Universal Power Plants Flight 13 February 1947 p 162 Archived from the original on 31 January 2018 Retrieved 22 August 2017 King H F 24 February 1949 A Call on Canadair Flight p 215 Archived from the original on 31 January 2018 Retrieved 22 August 2017 Dart Endurance Test Flight 31 August 1951 p 249 Archived from the original on 31 January 2018 Retrieved 22 August 2017 The Rolls Royce Civil Merlin Engine Flight 16 June 1949 Archived from the original on 31 January 2018 Retrieved 22 August 2017 Bridgman 1998 pp 280 281 Lovesey 1946 pp 224 226 Price 1982 p 51 Tanner 1981 A P 1565E Vol 1 Section II Lovesey 1946 p 218 a b Lumsden 2003 p 201 Hooker 1984 p 45 Hooker 1984 pp 46 50 52 235 247 Lumsden 2003 p 206 Rubbra 1990 p 71 Smith February 1942 p b Smith February 1942 p d King 1954 p 578 a b Lovesey 1946 p 220 a b c Lovesey 1946 p 219 Price 1982 pp 142 167 Price 1982 pp 153 154 170 Lumsden 2003 p 210 Price 1982 p 135 Hooker 1984 p 62 McKinstry 2007 p 205 Smallwood 1996 p 135 Lumsden 2003 p 212 Flight 1938 p 528 Payton Smith 1971 pp 259 260 Lloyd p 139 a b Harvey Bailey 1995 p 155 a b Gunston p 144 Air Ministry 1940 Air Ministry 1943 p 25 McKinstry 2007 p 356 Lovesey 1946 pp 222 223 a b Price 1982 p 170 Wilkinson 1946 p 195 Simons 2011 pp 126 127 a b Berger and Street 1994 p 199 Nijboer 2010 p 100 Fuel napoleon130 tripod com Archived from the original on 11 February 2017 Retrieved 22 June 2017 Pugh 2000 pp 195 196 Pugh 2000 pp 193 194 McKinstry 2007 pp 327 329 RAAF Museum Point Cook Beckles 1941 pp 78 79 1940 prices unadjusted for inflation War Cabinet Supply and Production Fourth Report by the Air Ministry Appendix V sheet 3 Archived 8 March 2016 at the Wayback Machine National Archives gov uk Retrieved 8 March 2016 Harvey Bailey 1995 p 12 a b c d e Gunston 2006 p 190 Derby factory closure Archived 3 April 2008 at the Wayback Machine news bbc co uk Retrieved 24 August 2009 Pugh 2000 p 193 Pugh 2000 pp 196 197 Crewe factory history Archived 5 March 2012 at the Wayback Machine jackbarclayparts co uk Retrieved 24 August 2009 War Cabinet Supply and Production First Report by the Air Ministry Appendix XI Archived 8 March 2016 at the Wayback Machine National Archives gov uk Retrieved 8 March 2016 War Cabinet Supply and Production Fourth Report by the Air Ministry Appendix XI Archived 8 March 2016 at the Wayback Machine National Archives gov uk Retrieved 8 March 2016 Pugh 2000 p 197 Lloyd and Pugh 2004 p 61 Robotham 1970 p 127 Lloyd and Pugh 2004 p 69 Pugh 2000 p 198 a b End of era for Rolls Royce plant news bbc co uk Retrieved 25 August 2009 Hillington factory history Archived 7 August 2009 at the Wayback Machine rolls royce com Retrieved 24 August 2009 a b c Nicholls 1996 p 103 Hooker 1984 pp 58 59 Nicholls 1996 p 105 1634 1699 McCusker J J 1997 How Much Is That in Real Money A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States Addenda et Corrigenda PDF American Antiquarian Society 1700 1799 McCusker J J 1992 How Much Is That in Real Money A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States PDF American Antiquarian Society 1800 present Federal Reserve Bank of Minneapolis Consumer Price Index estimate 1800 Retrieved 28 May 2023 Time Magazine 8 July 1940 Business Ford s Rolls Royces Archived 21 July 2013 at the Wayback Machine time com Retrieved 26 August 2009 Lumsden 2003 p 202 Bridgman 1998 p 283 Morgan and Shacklady 2000 p 608 Harvey Bailey 1995 p 62 Bridgman 1998 pp 281 283 a b Bridgman 1998 p 281 a b c Robertson 1973 p 144 Morgan and Shacklady 2000 p 129 a b c d Robertson 1973 p 145 Price 1982 p 145 Matusiak 2004 p 10 Smith 1942 pp 655 659 a b Smith 1942 p 656 Harvey Bailey 1995 pp 62 169 Harvey Bailey 1995 p 170 Air Ministry 1943 p 6 Harvey Bailey 195 p 172 Flight 1946 pp 92 94 flightglobal com Archived from the original on 29 July 2017 Retrieved 22 June 2017 Flight July 1946 p 99 Lumsden 2003 p 205 Lumsden 2003 pp 208 209 Lumsden 2003 pp 203 215 Lumsden 2003 pp 214 215 Lumsden 2003 p 214 Wilson Randy It s a Heinkel the Luftwaffe s workhorse Heinkel 111 bomber Archived 28 September 2006 at the Wayback Machine rwebs net The Dispatch Volume 12 Number 4 Winter 1996 Retrieved 6 September 2009 Green and Swanborough 1994 p 211 Pugh 2000 p 254 Harvey bailey 1995 p 83 Harvey Bailey 1995 pp 83 84 Martin 2002 p 58 The Shuttleworth Collection Hawker Sea Hurricane IB www shuttleworth org Retrieved 23 July 2019 The Shuttleworth Collection Spitfire VC www shuttleworth org Retrieved 23 July 2019 Photo and factfile Archived 12 March 2016 at the Wayback Machine Retrieved 12 March 2016 Merlin 60 or 70 series from Spitfire VIII Archived 29 October 2014 at the Wayback Machine Retrieved 12 March 2016 Engines List City of Norwich Aviation Museum Retrieved 27 August 2023 Merlins from crashed bomber Archived 21 April 2014 at the Wayback Machine Retrieved 12 March 2016 Merlin XX Archived 12 March 2016 at the Wayback Machine Retrieved 12 March 2016 Introducing the Merlin via the BBC requires plug in that may not work on some browsers Archived 9 May 2016 at the Wayback Machine Retrieved 12 March 2016 Merlin 28 Cosford Archived 12 March 2016 at the Wayback Machine Retrieved 12 March 2016 Science Museum website Archived 29 October 2010 at the Wayback Machine Retrieved 12 March 2016 Shuttleworth website Archived 6 August 2013 at the Wayback Machine Retrieved 12 March 2016 Smithsonian National Air and Space Museum Archived 6 July 2016 at the Wayback Machine Retrieved 3 March 2017 Wings Museum Archived 13 March 2013 at the Wayback Machine Retrieved 12 March 2016 Bridgman 1998 pp 280 282 Development of the Aircraft Supercharger Flightglobal Archive Archived from the original on 29 October 2014 Bibliography edit Air Ministry A P 1509B J 2 W Merlin II and III Aero Engines June 1940 London Air Ministry 1940 Air Ministry A P 1565B Spitfire IIA and IIB Aeroplanes Merlin XII Engine Pilot s Notes July 1940 London Air Data Publications 1972 reprint ISBN 0 85979 043 6 Air Ministry Pilot s Notes for Spitfire Mark F VII Merlin 64 or 71 engine Mark F VIII Merlin 63 66 or 70 engine Air Publication 1565G amp H P N London UK Air Ministry December 1943 Beckles Gordon Birth of a Spitfire The Story of Beaverbook s Ministry and its First 10 000 000 London Collins Clear Type Press 1941 Berger Monty and Street Brian Jeffrey Invasion Without Tears Toronto Canada Random House 1994 ISBN 0 394 22277 6 Bridgman L Jane s Fighting Aircraft of World War II London Crescent 1998 ISBN 0 517 67964 7 Fozard John W Sydney Camm and the Hurricane Perspectives on the Master Fighter Designer and his Finest Achievement Shrewsbury UK Airlife 1991 ISBN 1 85310 270 9 Green William and Swanborough Gordon The Complete Book of Fighters New York Smithmark Publishers 1994 ISBN 0 8317 3939 8 Gunston Bill World Encyclopedia of Aero Engines 5th Edition Stroud UK Sutton Publishing 2006 ISBN 0 7509 4479 X Harvey Bailey A The Merlin in Perspective The Combat Years 4th edition Derby England Rolls Royce Heritage Trust 1995 ISBN 1 872922 06 6 Hooker Stanley Not Much of an Engineer London Airlife 1984 ISBN 1 85310 285 7 King H F The Two R s A Commemorative History of Rolls Royce Aero Engines article and images Flight No 2363 Volume 65 7 May 1954 Lloyd Ian and Pugh Peter Hives amp the Merlin Cambridge England Icon Books 2004 ISBN 1 84046 644 8 Lovesey A C Development of the Rolls Royce Merlin from 1939 to 1945 Aircraft Engineering and Aerospace Technology Volume 18 Issue 7 London MCB UP Ltd July 1946 ISSN 0002 2667 Lumsden Alec British Piston Engines and Their Aircraft Marlborough Wiltshire Airlife Publishing 2003 ISBN 1 85310 294 6 Martin Karl Irish Army Vehicles Transport and Armour since 1922 2002 ISBN 0 9543413 0 9 Mason Francis K Hawker Aircraft Since 1920 3rd revised edition London Putnam 1991 ISBN 0 85177 839 9 Matusiak Wojtek Supermarine Spitfire Mk V Mushroom Model Magazine Special No 6111 Redbourn UK Mushroom Model Publications 2004 ISBN 83 917178 3 6 McKinstry Leo Spitfire Portrait of a Legend London John Murray 2007 ISBN 0 7195 6874 9 Morgan Eric B and Edward Shacklady Spitfire The History London Key Publishing 2000 ISBN 0 946219 48 6 Nicholls Robert Trafford Park the First Hundred Years Phillimore amp Co Ltd 1996 ISBN 1 86077 013 4 Nijboer Donald No 126 Wing RCAF Aviation Elite Units 35 Botley UK Osprey Publishing Limited 2010 ISBN 978 1 84603 483 1 Payton Smith D J Oil A Study of War time Policy and Administration London Her Majesty s Stationery Office 1971 Price Alfred The Spitfire Story London Jane s Publishing Company 1982 ISBN 0 86720 624 1 Pugh Peter The Magic of a Name The Rolls Royce Story The First 40 Years Cambridge England Icon Books 2000 ISBN 1 84046 151 9 Robertson Bruce Spitfire The Story of a Famous Fighter Hemel Hempstead Hertfordshire UK Model amp Allied Publications 1960 Third revised edition 1973 ISBN 0 900435 11 9 Robotham William Arthur Silver Ghosts and Silver Dawn London Constable 1970 ISBN 9780094566903 Rubbra A A Rolls Royce Piston Aero Engines A Designer Remembers Derby England Rolls Royce Heritage Trust 1990 ISBN 1 872922 00 7 Simons Graham M Mosquito The Original Multi Role Combat Aircraft Barnsley Yorkshire UK Pen amp Sword Books 2011 ISBN 978 1 84884 426 1 Smallwood Hugh Spitfire in Blue London Osprey Aerospace 1996 ISBN 1 85532 615 9 Smith G Geoffrey A British Masterpiece article and images Flight No 1731 Volume XLI 26 February 1942 Smith G Geoffrey Rolls Royce Merlin Sixty One article and images Flight No 1773 Volume XLII 17 December 1942 Tanner John The Spitfire V Manual AP1565E reprint London Arms and Armour Press 1981 ISBN 0 85368 420 0 White Graham Allied Aircraft Piston Engines of World War II History and Development of Frontline Aircraft Piston Engines Produced by Great Britain and the United States During World War II Warrendale Pennsylvania SAE International 1995 ISBN 1 56091 655 9 Wilkinson Paul H Aircraft Engines of the World 1946 3rd ed London Sir Isaac Pitman and Sons 1946 Some Trends in engine design article and images Flight No 1563 Volume XXXIV 8 December 1938 Rolls Royce Merlin 130 Series article and images Flight No 1935 Volume XLIX 24 January 1946 Two New Power Units article and images Flight and The Aircraft Engineer No 1961 Volume L 25 July 1946 Further reading editGunston Bill Development of Piston Aero Engines Cambridge Patrick Stephens 2006 ISBN 0 7509 4478 1 Henshaw Alex Sigh for a Merlin Testing the Spitfire London Crecy 1999 2nd revised edition ISBN 0 947554 83 1 Jackson Robert The Encyclopedia of Military Aircraft Bath UK Parragon Books 2006 ISBN 1 4054 2465 6 Price Alfred Spitfire Mark I II Aces 1939 41 London Osprey Aerospace 1996 ISBN 1 85532 627 2 Quill Jeffrey Spitfire A Test Pilot s Story London John Murray 1983 Crecy Publishing 1996 2nd edition ISBN 978 0 947554 72 9External links edit nbsp Wikimedia Commons has media related to Rolls Royce Merlin Merlin engines in Manchester BBC Post War Rolls Royce film on manufacturing the Merlin YouTube Merlin 60 series comparison drawings Spitfireperformance com Rolls Royce Merlin 61 sectioned drawing Vee Twelve Par Excellence a 1937 Flight article on the Merlin I and II A British Masterpiece a 1942 Flight article on the Merlin XX Universal Power Plants 1947 Flight article on postwar Merlin installations for civilian aircraft Merlin engine photo gallery from BBC Radio Leicester Sectioned image of possible turbocharger installation Flight International The Rolls Royce Merlin Aircraft Engines of The World Retrieved from https en wikipedia org w index php title Rolls Royce Merlin amp oldid 1201455824, wikipedia, wiki, book, books, library,

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