Day: 6 July 2008

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Rolls Royce Merlin Engine

The Merlin, a liquid cooled, 27 litre, V-12, piston aviation engine, was part of a range of developing engines produced by the world renowned company, Rolls Royce, and during the war over 150,000 engines were to be built.

Rolls-Royce had been developing engines since the turn of the twentieth century, and named the engines after birds, the Kestral, the Buzzard, the Peregrine and the Vulture.

In 1932, Rolls-Royce decided to replace the highly successful Kestral, and started developing the PV-12 engine (PV standing for Private Venture having no Government financing), later to be renamed Merlin. 

Early models of the Merlin A – F had many problems, and it was not until the model G was built, that a reliable engine was produce, being named the Merlin II, and was installed in the Supermarine Spitfire.

Up until 1935, the Merlin II had problems with its’ supercharger, sometimes meaning that the engine would cut-out in maneuvers in the Spitfire, and it was replaced by the Merlin XX, using a modified version of the licensed Farman two-speed/two-stage drive. The engine was also developed into the Merlin 130/131 for the De Haviland Hornet and the 133/134 for the Sea Hornet.

Development also continued in America on the Merlin by the Packard Motor Company of Detroit, the V-1650-1, replacing the Allison turbocharged engine of the P-40F’s, which had limiting altitude problems and production demands. This engine was to also power the P-51 Mustangs, giving it the ability to perform well up to 41,900 feet and achieving the speed of 437mph. Over 56,000 engines were produced by Packard Company.

In Britain, the mighty Merlin, was powering the Hawker Hurricane, the Avro Lancaster, Mosquito, and Spitfire. The engine was under constant development, doubling in power from 746 kW (1000 hp) in 1939 to over 1567 kW (2100 hp) by 1944, mostly through improvements in supercharging.

The Merlin was also developed into an engine for tanks the Rolls-Royce Meteor and the Rolls-Royce Meteorite, and for the navy for use in motor torpedo boats and air sea rescue boats.

A Merlin 500/45 engine was used in the Spanish Hispano Aviacion HA 1112MIL Buchon, based on the Messerschmitt Bf 109g-2.


The Rolls Royce Merlin engine in a Supermarine Spitfire, The Imperial War Museum, RAF Duxford The Rolls Royce Merlin engine in a Supermarine Spitfire



The Rolls Royce Merlin in a Spitfire
The Rolls Royce Merlin engine in a Supermarine Spitfire, The Imperial War Museum, RAF Duxford

The Rolls Royce Merlin engine, The Imperial War Museum, RAF Duxford

The Rolls Royce Merlin engine, The Imperial War Museum, RAF Duxford.


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Comments from the Spitfire article

I had a comment on a previous article titled Portrait of a Legend, Spitfire, which said :-

“they say the spitfire is the only aircraft in the royal air force that could fight against the German messerschmitt, focke wulf, and junkers in the ww2”

Firstly one would assume the book Portrait of a Legend, Spitfire, by Leo McKinstry, from the title alone, would be somewhat biased towards the Spitfire, but I found that the author McKinstry, through his extensive research, gave the downsides of the Spitfire, its’ faults and failings, not only of the hardware, the aircraft itself, but the people involved in the development, production and deployment, as well as the great attributes of this great aircraft, and the people involved, plus the courage and commitment of “the few” that flew it.

In its’ first incarnation as the Supermarine S6 seaplane, from which R J Mitchell created the Spitfire, powered by the mighty Rolls-Royce Merlin engine, the design proved to be a success, although having problems, with modifications, the basic design was continually developed and improved, to give various marks or variants, taking it from a racing aircraft, to a fighter, a fighter bomber, and a photoreconnassiance (PR) plane.

The photoreconnassiance variant, from the Spitfire PR MARK 1A through to the Spitfire PRXIX often flying unarmed, proved to be highly efficient, being able to take high quality pictures at low level and at altitudes from 35,000 feet with its’ F52 36-inch-focal-length lens. The Spitfire PRXIX was flown in 1952 in Hong Kong by Flight Lieutenant Ted Powles to an altitude of 51,000 feet, and in a dive, recorded a speed of 690 miles per hour or Mach 0.94. Not bad for a piston driven aircraft, and attributed to the great design.

Prior to the Battle of Britain (10th July to 30th October 1940), the RAF’s strategy had been, and had been proved in previous conflicts including the Spanish Civil War, that bombers were the best strategy, as was the doctrine of Sir Hugh Trenchard, Chief of Air Staff, and it was that strategy of high concentration bombing that Hermann Göring, Commander-in-Chief of the Luftwaffe, the German airforce, would employ against the airfields of the RAF, and then the bombing of London called The Blitz.

Göring realised that if the Germans had air supremacy, the defeat of Britain, codenamed Operation Sealion, would be easy, and thus Hitler ordered the invasion to begin mid-September 1940. But, he underestimated the strength of the RAF and the two aircraft used at Dunkirk, the Spitfires and the Hurricanes, as Theo Osterkamp, one of the leading Luftwaffe fighter pilots told Göring, the Spitfire had proved to be as good as any German fighter, but his comments were dismissed.

The RAF knew this strategy would be employed, and built up the Fighter Command, but there were great problems in manufacturing of fighter aircraft, not enough factories, and not enough good strong leadership in the government and business. That changed with the appointment of Lord Beaverbrook.

After the First World War, development of aircraft had been slow in many countries, especially war planes, and so it was in Britain. The Gloster Gladiator still a biplane, as was the Westland PV4, the Bristol Bulldog and Hawker Fury. Much slower biplanes with fixed wheels, fabric-covered wings, exposed radial engines, like the Gloster Grebe, and the Armstrong-Whitworth Siskin, had hardly advanced since the 1st World War.

As the British were disparately trying to update the design of the RAF’s fighter aircraft as issued in the specifications (design requirements) F7/30, F10/35 and F36/34, a number of designs and prototypes of aircraft were produced, and the two preferred were the Hawker Hurricane and Supermarine Spitfire both monoplanes, especially as the Gloster Gladiator as Sir Hugh Dowding said, would be of “no use against the 270 mph machines” of the fast German bombers.

Hawker Hurricane IIB  Replica Supermarine Mk 24 DU-X

                Hawker Hurricane IIB                                                                                    Replica Supermarine Mk 24 DU-X

Both the Hurricane and Spitfire were flown against the Germans in the Battle of Britain, with the Hurricane having a greater success than the Spitfire, but it was the Spitfire that was the better aircraft, having a better handling characteristic, higher speed, higher ceiling, better aerobatic capability, loved by the pilots, and had been sold to the British public as the saviour of the war effort, with communities and individuals making collections and donations to build Spitfires.

Both aircraft were employed throughout the rest war, as air supremacy became a major factor.

It was the Spitfire adding to the small numbers of Hurricanes that replaced the three Gloster Gladiators, biplanes known as Faith, Hope and Charity, that eventually repelled the German attacks and onslaught on Malta, to gain supremacy in the Mediterranean and thus have supply routes to the war in North Africa.

It has been estimated that in the Battle of Malta, the Luftwaffe had 249 aircraft destroyed and 50 damaged, with the Italians, Reqia Aeronautica, adding another 60, against 148 Spitfires and 45 Hurricanes losses.

A variant of the Spitfire the Seafire, a Naval aircraft flying from aircraft carriers, proved invaluable in North Africa, and Montgomery’s triumph at El Alamein and in Operation Torch in Morocco and Algeria.

In Sicily the Spitfire played a crucial role in destroying ground defenses and providing air cover.

Submarine Spitfire Mk VB, RAF Duxford
Submarine Spitfire Mk VB, RAF Duxford


In the Far East, the Japanese were threatening to overrun Burma and enter India. With the help of Spitfires, the Allies turned back the Japanese at the Battle of Kohima. The Japanese Mitsubishi Zero and Nakajima Hayabussa having overwhelmed the Hurricane, but being matched by the Spitfire with its’ superior climbing and maneuverability.

Before the start of the Second World War and during, Germany built-up a strong air force, comprising of bombers and fighter aircraft. The Messerschmitt 109 (Me109), the Messerschmitt 110 (Me110), Focke-Wulf 190 (Fw 190), the Junkers bombers (Ju 88) (Ju 86P), the Heinkel (111), and the Stuka dive-bomber.

Messerschmitt Bf 109
Messerschmitt Bf 109


With this strength the in March 1939, the Third Reich occupied Czechoslovakia and began to threaten Poland. The British prime minister, Neville Chamberlain, having being, it is said, to negotiate for conciliation with Hitler, declared war on 3rd September. Had he been buying time to build-up the strength of the RAF? The British certainly did not have any strength to pursue a war.

As the war progressed, the Third Reich invaded Holland and France, with the Luftwaffe so strong, that many of the outdated French air force never leaving the ground. But all the time, the British were building up the number of fighter aircraft.

As above, Göring had miscalculated the resolve of the British, the strength of the RAF and the power of the Spitfire, plus he was not aware of the newly invented RADAR system which allowed Fighter Command to “see” where the next attack was coming from, so that the Dowding system (Sir Hugh Dowding) of dispersing the squadrons of Spitfires and Hurricanes.

Again Göring miscalculated, with the British on their knees, he changed tactics away from attacking the airfields, giving the RAF chance to strengthen and fight back.

Each side developed their aircraft, so that one would out perform the other, but it was the Spitfire that proved the most successful, even outperforming the jet aircraft (Messerschmitt 262) produced at the end of the war and the V-1 ram-jet or rockets (doodlebugs) that attacked London. Other aircraft would be developed, the Hawker Typhoon and Tempest, the US Thunderbolt,

Spitfire Mk XIV a match for the Bf 109  V-1 Doodlebug Rocket Ram-Jet
      Spitfire Mk XIV a match for the Bf 109                                                                             V-1 Doodlebug Ram-Jet (Rocket)


The Spitfire was good, and was sold to many countries as a fighter, including, Russia, China, Turkey, Egypt, Thailand, Australia to name just a few, to end service in the British RAF on the 9th June 1957.

Perhaps the last words of how great the Spitfire was should be left to the German pilots, who when spotting the aircraft would be heard to shout over their radios, “Terrorlieger – terror flyers“, “Watch out! Spitfire“, “Achtung! Spitfeurer!“

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