You might remember the Vincent Picador, a Vincent motorcycle engine used in some WWII target drones and whose left over high performance parts are still prized by Vincent motorcycle builders today. Well, Vincent isn't the only motorcycle company that built engines for drones, it looks like Harley Davidson got in on the action more recently, only, Harley Davidson didn't slap a V-Twin out there, though some have done that, instead, Harley went the high tech route and built rocket engines. Yes, ... Harley Davidson rocket engines!
This is definitely in the "things I didn't know" category, the Motor Company actually built over 5000 LR-64 rocket engines to power U.S. Navy target drones during a 30 year period beginning in the mid 1960s. The engines were built in the York, Pennsylvania plant.
The LR-64 is currently on display in the Collection X exhibit at the Harley Davidson Museum in Milwaukee which runs until August 21st. So if you want to see these rocket engines for yourself, now is a great time to visit.
Link: Harley Davidson Museum