The Original Hemi

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I was doing some reading on the history of the Hemi and wasn't entirely surprised to find that it's rooted in aviation, like many things in automotive history. This article goes over the history of the XI-2220 Hemi V-16, which was build specifically for the P-47 Thunderbolt. Considering the day and age, the 2,440 pound engine produced 2,500 horsepower and offered 100% efficiency at an altitude of up to 25,000 feet. While WWII was effectively over, luckily for us Chrysler adopted the hemispherical head design in automobile engines.



propeller-end hemi.jpg
 
Originally Posted by EricG
Just an FYI, the P47 Thunderbolt used a R2800 Pratt and Whitney Radial!


Right, but Chrysler designed the engine for use in the P-47. Here is a picture of the experimental P-47.

Republic-XP-47H.jpg
 
I saw the IV-2220 in the Chrysler Museum in Auburn Hills, MI before the 2009 bankruptcy. They also had a 5-bank tank engine, and a 60's vintage engineering dyno setup with a 426 Hemi.
Sadly, the museum has been closed since the Fiat merger. That building is now the headquarters for Alfa Romeo.
Many WW2 vintage engines were hemi's. The major US radials by Curtiss-Wright and Pratt & Whitney, the Novi Indy V8, the Offy 4, the 1927 Delage straight-8, the 1932 Alfa Romeo Tipo B straight-8, the Auto Union Type C V16 and Type D V12, the 1951 BRM V16, etc...

The IV-2220 was installed in a P47 and test flown, but it was redesignated something else.
 
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My father has a DeSoto HEMI in his garage or upstairs in his garage. He grew up in the garage as that was a house.

I believe it's a 330 HEMI
 
Originally Posted by EricG
Just an FYI, the P47 Thunderbolt used a R2800 Pratt and Whitney Radial!

And just an FYI, reading the article he linked in his post would have helped you here.
 
Originally Posted by spk2000
100% efficiency. Is that even possible with a gas engine? What about heat losses?

That's my fault with wording, I meant that it could achieve 100% of it's power at 25,000 feet.
 
2 valve Hemis are cool but give me a 4 valve Pentroof because they allow for 40% greater intake and 67% greater exhaust...
 
Oh well, BLS...if we are going that far off topic, rotary valves offer far more open area...
Sir Harry Ricardo was testing 5 and six valve heads in 1911...Wankels have pretty big port areas also...particularly with respect to swept volume
 
Harry Ricardo, after years of study and testing, came down to the conclusion that the Burt-McCollum single sleeve valve was the best system for engine breathing. It was no accident that Bristol and Napier built WW2 aircraft engines using them. Bristol had 4-valve radials before switching to sleeve valves. The Napier Sabre is legendary, both for its power output and unreliability. But is was only beginning to mature when the war ended, and the switch to jet propulsion made all recip engine development moot.
 
This was a great idea by Chrysler, but the 2 biggest problems were the approaching end of the war, and P&W not sitting on their laurels.

By the end of the war, P&W had successfully tested the R2800 at 3600HP for 250 hours straight with no failures. The P-47 was routinely the fastest piston plane of the war, with an insane climb rate of 4900FPM. This is why P-47's were the choice for buzz-bomb interception.

The other big difference between the Chrysler engine and the R2800 is that P&W radials were well-known to bring pilots home with entire cylinders shot off of the engine. The glycol cooled engines could be completely taken out with one placed shot penetrating any part of the cooling system.

This was expecially important toward the end of the war, when there wasn't much Luftwaffe to shoot down anymore, and P-47s did a LOT of ground attacks. My grandfather told me that when he'd fly in to shoot up ground targets, that there may have been more times he got shot than didn't. The R2800 didn't care. Cylinders missing, no oil pressure, whatever. Just kept chugging along. The whole plane was like that, however. Many came back to the airfield with half a wing missing, rudders gone, tail fins gone, 1 foot holes through the fuselage, whatever.

Most of his air-to-air action was at high-altitudes with the bombers. At the time, the FW-190 was a particularly nasty airplane the Germans were using for bomber interception. The "butcher bird" didn't hold a candle to the P-47. Made plenty of them regret diving through a bomber formation, since the P-47 could out-dive pretty much anything. The first ME-262 jet was killed by a P-47 on a dive attack during a dogfight protecting bombers.
 
Originally Posted by DoubleWasp
The P-47 was routinely the fastest piston plane of the war, with an insane climb rate of 4900FPM. This is why P-47's were the choice for buzz-bomb interception..


Historically speaking the P47 wasn't the fastest and the Spitfire was the choice for Buzz Bomb interception...





WW2TopSpeeds.jpg


SpitfireV1a.jpg


SpitfireV1c.jpg
 
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That chart is out of date. The later models of P-47 reached nearly 500mph in level flight.

The Spitfire is an RAF plane. But even where the RAf was concerned, it was all about the Tempest and the Mosquito, with the Spitfire being the exception.

The plane of choice for the US was the P-47M. There were modified Mustangs as well, but the modified Mustangs and P-47Ms became a moot point when the V-1 sites were overrun.
 
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