The Packard L-12 is a Liberty 12 That's a bit of a Wikipedia deep-dive on its own. It went into everything from this: To this: An aircooled radial diesel aircraft engine is such a fucking terrifying idea that I'm not surprised it's in a museum. You meant the KB-50J, which was a jet'n'piston powered tanker based on the B-29. The J-47 was in bloody everything. I found one for free in Hemmings motor News once and it was only a few miles away (talk about weird). I ended up connecting the owner with Survival Research Labs. No idea what they did with it. The RR/Packard merlin was superseded by the Allison V1710, the Chevy Smallblock of WWII aviation. They were so stunningly common that they basically fostered the industry of offshore powerboat racing and formed the backbone of unlimited-class hydroplane racing into the '90s. The U3 is still running an Allison V1710.
I'm still reading that Liberty 12 article. What blows me away about that engind, more than anything, is the time table. It took five days to design, a month to build, and another month to be tested and approved? That sounds insane by today's standards. Also, I wonder how distinct the shape of that V1710 is. I could almost swear I've seen the shape of that engine block somewhere, but not in relation to aircraft or boats.
I would guess that the fine folx at Fageol probably had a lot of the legwork done already. The V1710 is a 90-degree OHV V16. The Merlin is a SOHC V-12. There aren't that many different ways to do that; the motor on my Benelli is a 1000cc water-cooled triple. The motor on most Triumphs is a 1000cc water-cooled triple. The average mook, upon seeing a Benelli motor, assumes it's a direct copy of the Triumph... despite the fact that it rotates the other direction. It's not that they're idiots, it's that there aren't that many triples in the motorcycle industry. Externally similar... despite the fact that the Cadillac is a flathead.
That Liberty L-12 went into a ton of stuff. Some crazy men stuffed three into a car for an attempt at a land speed record which tragedy around that car aside, is awsome. I will admit that after a while, the engines start to blur together. It probably takes something really distinctive or really iconic to stand out.