testtest

The hemi for the p47.

Also known as the XP-47H
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USMC6094 said:
Also known as the XP-47H
View attachment 71639
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Years ago, while I was going through A & P school, one of my power plant instructors spent a little time discussing "weird and different" types of recip engines. This was one he brought up. When the OP posted this thread, I remembered the "hemi"! lol When I was going through the school, one of my vehicles was a Dodge Charger SRT8 with whatever size 'Hemi" was in it at the time (long since gone, but I do miss it). Right after class was over, he wanted me to let him check out under the hood of my SRT8. lol
 
OldGrunt said:
Years ago, while I was going through A & P school, one of my power plant instructors spent a little time discussing "weird and different" types of recip engines. This was one he brought up. When the OP posted this thread, I remembered the "hemi"! lol When I was going through the school, one of my vehicles was a Dodge Charger SRT8 with whatever size 'Hemi" was in it at the time (long since gone, but I do miss it). Right after class was over, he wanted me to let him check out under the hood of my SRT8. lol
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I drive a 2014 RAM 2500 with a 6.4 liter Hemi, I don't know about earlier models, but all current Hemis have two spark plugs per cylinder. And aircraft engines (recips) are required to have the same setup.
 
The only hemi I’m really familiar with is the 426 (and a little bit with the 276 “Firedome” that DeSoto briefly used).
 
last2brake said:
EZ....you just use the radial's stock radiator. It's a bolt-in swap.

Actually, I wonder if the new "hemi's" even have hemispherical combustion chambers anymore.
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They're not.

This dude seems to know what he's talking about.


"No, they are not true Hemis. They are very similar though and share design characteristics. The modern "semi-hemi" has large quench pads on the side, but still uses opposing canted valves.
It's important to know that this is a GOOD thing. An important aspect of engine design is a compact, low surface area combustion chamber. A true hemi is not a good design if high compression is needed, as the piston dome required creates a combustion chamber that is wide and thin. This slows flame propogation, meaning you need more timing advance to get peak pressure at TDC, meaning you're doing more negative work.
The modern hemi still has a very open combustion chamber. As shown below, you can see the quench pads, twin spark plugs, and opposing canted valves. All good features, and all improvements on the original hemi for an engine that isn't going to see use in a funny car with crazy boost.
http://www.shophemi.com/images/PRODUCT/large/198.jpg
And no, most modern engines do not use a hemi design as inevitably comes up in these threads. The typical 4 valve head is called a pent-roof."
 
USMC6094 said:
Public Service Announcement, radial engine's, don't have radiators.
They have oil coolers.
An air cooled radial engine, is just that, AIR COOLED
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That was an advantage with the radials in warplanes. No vulnerable cooling system for gun fire to destroy. I have flown enough radials to know of whence I speak.
 
USMC6094 said:
Public Service Announcement, radial engine's, don't have radiators.
They have oil coolers.
An air cooled radial engine, is just that, AIR COOLED
Click to expand...
Of COURSE radial engines are air-cooled.

I was trying to be sarcastic. There's no way a water-cooled Hemi could be a bolt-on engine swap into air-cooled airplanes

And, yep, P51s were water-cooled, and it was an exploitable weakness from underneath.

My dad flew P47s and P51s. He loved having the big engine blocking bullets, but he loved flying the Mustang more. He even had to bail-out of one.
 
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