Another great idea that should have gone into production: The Matra Bagheera U8 engine
Antique Machinery and History | U-Boat engine question- what do these things do? | Practical Machinist - Largest Manufacturing Technology Forum on the Web
Toyota U engine - Wikipedia
King-Bugatti U-16 Engine | National Air and Space Museum
the Bugatti revue: Bugatti License Aircraft Engines
Continental O-470-U Engine W/Accessories Seen 1330 SMOH 285 H.P. Cessna 182 - Air Salvage
U engine - Wikipedia
King-Bugatti U-16 Engine | National Air and Space Museum