Few engines throughout history have achieved a near mythical status among its admirers. Fewer still can share credit for the rescue of an entire nation. Perhaps only the Rolls-Royce Merlin engine can claim both distinctions. During the Battle of Britain, it was the Merlin that powered the Royal Air Force Hurricanes and Spitfires that were England’s only effective defense against German air attacks. With the battle won, and the engine’s reputation thus established, the Merlin would become the stuff of legend and the powerplant of choice for numerous other aircraft.
Even before the 1940 air battles over England, it was apparent that demand for the Merlin was far outpacing Rolls-Royce’s ability to produce them. The Ford Motor Company was asked to build 9,000 Merlins for both England and the US. Ford initially accepted the deal, but later reneged. Henry Ford explained that he would only produce military items for US defense. Interestingly, Ford of Britain in Manchester, England ultimately produced 36,000 Merlin engines, beginning at the same time period. Of course, Ford’s American factories would indeed become vital to the war effort. They manufactured unfathomable quantities of airplanes, jeeps and other war materiel--but not Merlins.
Following Ford’s refusal to build the Merlin, a similar deal was presented to the Packard Motor Car Company. At that time, Packard automobiles were considered the “Rolls-Royce of America” by virtue of their luxury and quality. The company also had experience producing airplane engines and large V-12 powerplants used in speedy PT Boats. Packard accepted the offer from Rolls-Royce and earnestly began preparations to build Merlins at their Detroit factory.
Two Countries Divided By A Common Language
There are many obvious challenges posed by producing a British-designed engine in America. Just the task of converting all of the measurements from
metric imperial to US Standard units was daunting enough. This job was made even more difficult by the unprecedented complexity of the Merlin. The 1,649 cubic inch V-12 engine is comprised of more than 14,000 individual parts (knoll that!). It was, and still is, often called “a watchmaker’s nightmare.
Engineers at Packard soon discovered that Rolls-Royce did not design the Merlin for mass-production. The manufacturing tolerances were much looser than Packard’s standards. This was because Rolls-Royce had never implemented mass-production techniques to their assembly lines. Rather, they employed highly-trained “fitters” to assemble the engines. The fitters filed or otherwise massaged individual parts to achieve a precise fit. They even tightened critical bolts by trained feel, rather than with calibrated torque wrenches. In effect, each Rolls-Royce-manufactured Merlin was a hand-built engine that reflected the company’s traditions of premium quality and craftsmanship.