The Germans used synthetic oil in their aircraft in WWII, as did the Allies, because of the extreme cold at the high altitudes. The Merlin was one of the most powerful fighter engines of its era, and flew at the higher altitudes where normal mineral oil would congeal.
I read a theory once that the Merlin, as installed in the British Spitfire, was responsible for winning WWII. Because of the power and high service ceiling of the Spitfire, the Battle of Britan was won, and Germany was denied occupation of England. Without England as a land base, the U.S. could not have fought the European front as it did, and the war might have had a different outcome. Or at least would have lasted much longer.
[ January 31, 2003, 03:13 PM: Message edited by: TheLoneRanger ]