Few can have imagined when Rolls Royce first ran its new PV12 aero engine in 1933 that the soon renamed Merlin would go on to be the most famous engine in the world. In a production run that lasted from 1936 to 1956 Rolls Royce built over 160000 Merlins in 50 different variants and over 50000 examples were built in the USA under the Packard name. The early versions of the Merlin produced around 1000 horsepower but late version Merlins were rated at up to 2000hp and it was Merlin and Packard en