475 mph. That is highest maximum level speed recorded by any American combat aircraft in World War II.
Obviously a Mustang, right? Or maybe a Bearcat if we stretch the definition of World War II combat types?
I’m guessing you all can deduce from the pictures that was actually a Thunderbolt.
In the ongoing effort to get the most from its basic design, Republic pulled three P-47D models from the production line and put the latest version of Pratt & Whitney’s R-2800 engine on them. They tagged this new sub-type a XP-47M. Actually, they did this to four sequential airframes, but one of them was further modified into the XP-47N. We’ll save that story for another day.
The particular engine used was the R-2800 -14W/-57, also known as the “C Series”. This was paired to a new CH-5 turbosupercharger and given water boost. That is a lot of mumbo jumbo and I don’t honestly know what all distinguishes different versions of the engine, just note that horsepower and reliability were typically improved over the life of any engine. MOST World War II era aircraft had mechanical supercharging, exhaust driven turbocharging, or both. An engine with neither is called “normally aspirated” and often works fine on the ground, but performance will drop off quickly as the air thins above 10000 feet. The turbo or super charging increases pressure and airflow through the engine. It is often seen with multiple speeds or stages, that got increasingly more sophisticated as the War went on. The better an aircraft’s performance is at a range altitudes allows it to better set the terms of combat. Especially if you can always get above the other guy and have good speed while doing it. The best high altitude types usually had both types (turbo- and super-) like the Thunderbolt.
The water boost appeared on several late War variants of the R-2800 engine. It could, for 5 minutes or so, cool the cylinder heads to allow denser air into the piston and increase combustion power. This works until the water reservoir heats up to the point its no longer cooling.
At maximum boost this engine put out one horsepower per cubic inch of displacement. That’s 2800 horsepower. That’s a lot.
The P-47M originally had only a single hard point under the belly to keep it light and sleek (errr, well, for a Thunderbolt). But it was quickly determined more would be needed both for extra fuel and ordinance, so underwing pylons were usually added. Only 130 of these ultimate hot rod Thunderbolts were built for the exclusive use of the 56th Fighter Group; it had already been decided they would be the only Thunderbolt group still tasked with air-to-air missions in the last months of the European air war.
Unfortunately, when the P-47M was first delivered in January of 1945 it had serious problems. This mostly meant engine failures. After several frustrating weeks, including the dreaded consideration that the 56th might convert to Mustangs (!), the problems were finally traced to the ignition harness. This did require new hardware on every single “M”, but in the end the Group flew this very fast mount for the last months of the European War.
This particular plane was with the 56th Fighter Group, 63rd Fighter Squadron. It was flown by Lt PG Kuhn who had one kill in the air, four on the ground. By 8th Air Force rules that made him an ace.
This is the Tamiya kit with Aeromaster decals. This was also my second try with Alclad metallic paint, and I would say I was much happier this second time around. I still have some learning to do! But I’m more confident I can hide my mistakes this time around and feel less need to explain myself. So hey, that’s progress!