The Redrup Radial engine is new to me but it's actually quite old. After all of our coverage of radial engine motorcycles using the Australian Rotec 7 cylinder radial like the one built by Jesse James and the radial motorcycle built by JRL Cycles that they actually plan to produce, I received several pointers to the Megola radial engine used in a motorcycle many years ago where the engine was mounted in the front wheel. But no one mentioned the little Redrup.
The Redrup Radial was a 3 cylinder, 120 degree radial engine displacing 309cc. I ran across a short article in the October issue of The Classic Motorcycle that said it was built in the UK from 1919 to 1922 though actual numbers built are unclear and probably less than 150. The engine was designed by Charles Redrup, an aeronautical engineer and the "Redrup Radial" as the motorcycle was known, was assembled by a close friend of his, Monty Beaumont.
Digging around for photos of this motorcycle lead to an interesting outcome, three photos and each had the engine mounted on a different axis. The latest of these, the red motorcycle at right, was actually built later by Charles Redrup and his son after WWII. The engine was a smaller 250cc version with the crankshaft in a vertical position and mounted in a Royal Enfield frame.
Interesting stuff and another indication of neat ideas that have come before.