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The famous British Rolls-Royce Merlin engine powered the Spitfire and Hurricane fighters during the Battle of Britain in 1940. In September 1940 Packard agreed to build the Merlin engine for both the American and the British governments, and adapted it for American mass-production methods.
The first two Packard-built Merlins to be completed were demonstrated on test stands at a special ceremony at the Packard plant in Detroit on Aug. 2, 1941. Full production began in 1942. In total 55,511 Merlins were produced in the US for the Army Air Forces (54,714 by Packard and an additional 797 by Continental).
The Army Air Forces used the V-1650 (as the US version of the Merlin was designated) almost exclusively in the famed P-51 Mustang, for it provided greatly improved high-altitude performance over the Allison V-1710 engine used in earlier series of that airplane.
Hence, both the Spitfire and the P-51 Mustang, two of the best fighters of World War II, were powered by the iconic Merlin.
So, which was better between the Spitfire and Mustang?
Pete Feigal, former Pro Military Artist and Aviation Expert, explains on Quora.
‘Actually they didn’t have the same engine, both V-1650 Merlin’s, yes, but one (high powered Mk IX and others,) used Rolls Royce 61/63/66 and 70 series engines, and the P-51 used a Packard-licensed version of the Merlin.
‘And there were two main versions of that Packard Merlin 1650: the -7 version was geared so its supercharger drive speed would be optimal at War Emergency Power (WEP) with 130 octane fuel at 6200 feet with the supercharger in low speed and at 19,300 feet in high speed. (The -7 is the Merlin typically quoted for HP numbers.) Making 1,720 HP.
‘But this version was NOT optimal for escorting high altitude bombers at 25,000 feet so another Packard Merlin version, the -3 which had different supercharger drive ratios which changed the shaft speed, was introduced. The -3 engine actually has less power overall but gives it more power at 17,000 feet at low speed and 28,800 feet at high speed. Making 1,595 HP.
‘Many P-51’s were retrofitted with the -3 supercharger kits giving less overall HP but more where they needed it at high altitudes.
‘And as the Bf 109G’s, for instance, start running out of steam/manifold pressure at only 18,800 feet that was a huge advantage for the P-51s. The -3 has 1595 HP on 120 octane fuel vs 1720 for the -7 but it’s a question of *where* that power is *available* at 25,000 feet and higher where the bombers were flying.
‘As for “Better Airplane,” the P-51 could strike at enemy targets, including Luftwaffe training bases, as far away as western Poland, causing mayhem along its entire 1,650 mile range. Being a “work horse” It wasn’t as agile or as maneuver as a slender “race horse” of a Spitfire, but it could hold its own being well balanced in climb, dive, roll and “boom & zoom.”
‘The Spitfire was better armed and as slippery as anything in the sky, but had very little range, sadly condemning it more and more to defensive missions in Northern France. You might see Mosquitos over Berlin but never Spitfires, and that’s were the fight more and more was.’
Feigal concludes;
‘Both had great cockpits and visibility and if the P-51 could drain its internal tank before getting in a fight and not throw off its COG, it did well in a dogfight.
‘Apples/oranges.’
Photo credit: Alan Wilson from Stilton, Peterborough, Cambs, UK and Ronnie Macdonald from Chelmsford, United Kingdom via Wikipedia
