Author Topic: How much extra hp could the R-2800 deliver?  (Read 1747 times)

Offline AquaShrimp

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How much extra hp could the R-2800 deliver?
« on: January 08, 2008, 01:43:10 AM »
I've heard about P-47s being field modified by both crew chiefs and field reps from Republic to deliver a considerable bit more horsepower than the stock model.  Anyone have any figures on this?  Was there ever any official testing of the top speed, rate of climb, or acceleration on these special P-47s?

Offline Viking

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How much extra hp could the R-2800 deliver?
« Reply #1 on: January 08, 2008, 04:10:17 AM »
All engines can be tuned to produce more power than the manufacturer's standard. Warbird racers can get about 3000 hp out of a Merlin engine, but also call it "riding on a hand grenade". However during the war official restrictions on boost and RPM were as much for preserving engine longevity as for engine reliability. Jury rigging engines in the field did happen, but I'm not certain as to how wide spread that practice was.

As for official testing ... I hardly think so since these planes were anything but official.

Offline Angus

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How much extra hp could the R-2800 deliver?
« Reply #2 on: January 08, 2008, 05:40:24 AM »
A Merlin was already tuned to more than 2000 hp in 1939...
Anyway wouldn't the R2800 have topped with a nice figure when running on high oct fuel? Widewing will know this, just wait...
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Offline B3YT

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How much extra hp could the R-2800 deliver?
« Reply #3 on: January 08, 2008, 08:48:50 AM »
the RAF used to re-mill all the Pacard merlin engines when they were shipped over. got an extra 300BHp out of it.
As the cleaners say :"once more unto the bleach"

Offline AquaShrimp

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How much extra hp could the R-2800 deliver?
« Reply #4 on: January 08, 2008, 09:45:29 AM »
I've read about some Mustang pilots having their Merlins modified to pull 79 inches of manifold pressure.

Offline beau32

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How much extra hp could the R-2800 deliver?
« Reply #5 on: January 08, 2008, 06:29:19 PM »
http://www.wwiiaircraftperformance.org/p-47/p-47.html#p47-n

here is a awsome website that should give you plenty of info. Hope you like.
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Offline F4UDOA

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How much extra hp could the R-2800 deliver?
« Reply #6 on: January 16, 2008, 09:09:27 AM »
Graham White's book on the R-2800 mentions being able to get over 3,000HP out of a 2800B block which was not rated for 115/145 fuel only the 100Octane was approved on this engine but this was in testing.

That is the engine in the F4U-1 and F6F-3/5. The F4U-1D by wars end was rated at 2300HP because of RAM air while the 2800C block in the P-47M and F4U-3/4 was rated as high as 2800HP on production aircraft.

If you want to see the max performance test of these aircraft just look here

WWII performance test

You will find the P-47B/C/D/M and N test as well as pretty much everything else you could ask for.
« Last Edit: January 16, 2008, 09:13:45 AM by F4UDOA »

Offline trigger2

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How much extra hp could the R-2800 deliver?
« Reply #7 on: January 17, 2008, 09:38:51 AM »
Wheres widewing when you need him?? :confused:

Oh well, I'm not sure if the figures are correct as to how much more power the engine could pull but as viking said, any engine can be tuned up to go above and beyond what the manufacturer has it made for.  Quite common in motorcycles "boring out the engine" and I'm sure what you could do with a motorcycle you could do in a plane...
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Offline AquaShrimp

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How much extra hp could the R-2800 deliver?
« Reply #8 on: January 17, 2008, 11:25:18 AM »
I read on an air-racing board (while reading about a radial engined P-51) that the R-2800 could produce 4000 hp.

Offline Widewing

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How much extra hp could the R-2800 deliver?
« Reply #9 on: January 17, 2008, 07:02:24 PM »
Republic Aviation did extensive testing of R-2800 engines. The C series engine installed in the first YP-47M was subjected to 250 hours of severe testing. Lowery Brabham of Republic stated that they routinely attained 3,600 hp out of this engine, with no recorded mechanical problems.

Bodie discussed this testing in some depth in his P-47 book. He interviewed Brabham.

My regards,

Widewing
My regards,

Widewing

YGBSM. Retired Member of Aces High Trainer Corps, Past President of the DFC, retired from flying as Tredlite.

Offline skaltura

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How much extra hp could the R-2800 deliver?
« Reply #10 on: January 17, 2008, 07:56:00 PM »
Bodie also claims how "the eight heavy machine guns of the P-47 put in a target more weight than the 4 cannons of the Tempest per second" which is an outright lie. When confonted with the facts, he became abusive.

He also seems to seriously believe that the XP-72 was good for 480 mph at sea level...

And that Truman was a miserably coward for not "nuking those stinking Chinese" in Korea. His words, not mine.

Offline AquaShrimp

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How much extra hp could the R-2800 deliver?
« Reply #11 on: January 17, 2008, 09:42:48 PM »
I read that an inline-engined version of the P47 (using a chrysler engine) achieved 490mph in level flight.

Offline Widewing

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How much extra hp could the R-2800 deliver?
« Reply #12 on: January 17, 2008, 11:08:29 PM »
Quote
Originally posted by skaltura
Bodie also claims how "the eight heavy machine guns of the P-47 put in a target more weight than the 4 cannons of the Tempest per second" which is an outright lie. When confonted with the facts, he became abusive.

He also seems to seriously believe that the XP-72 was good for 480 mph at sea level...

And that Truman was a miserably coward for not "nuking those stinking Chinese" in Korea. His words, not mine.


I talked with Ken Jernstedt at a AVG get-together in the middle 1990's. Since he was one of the two XP-72 test pilots, I asked him about the aircraft and Bodie's claim. He was tickled that someone wanted to talk about something besides the AVG. Jernstedt said he could reach about 395 mph a few hundred feet above Long Island Sound. This was at MIL power. That's quite fast, but still well below 480 mph. Ken was nearly blind by then, but he still had a twinkle in his eye.

I spent a few years working with Bodie (after Jeff Ethell died) in my spare time, co-authoring several magazine pieces and helping him with various projects. Warren was very difficult to work with. Moody, cranky and downright surly at times. Eventually, I grew quite weary of it and simply quit. I haven't talked to him in years. I did, however, steal his publishing company name... Widewing.

I argued with him about the XP-72's speed, but he insisted that Carl Bellinger told him "480 mph". He probably did tell him that, but Warren accepted it without question. Clearly, it was an error. Nonetheless, I couldn't change his mind. Yeah, the XP-72 could reach 480 mph, in fact it attained 490 mph. However, it did that at 25,000 feet, not at sea level.  

Whatever Warren's faults were, he has one of the best collections of historic and vintage aviation photos (many of which he took himself) in existence. He has a huge library of primary source documents, especially from Lockheed. He was the Skunk Works tech pub manager for many years.

Bodie may lack some of the skills of a trained historian, and does not possess the opened minded approach required to be objective. However, he is still one of the most knowledgeable people alive when it comes to aviation history. His work is not without error. However, it is still among the best in terms of depth and content.  

Warren was always a very opinionated fellow, and a product of his generation.

Oh, and I'm not a big fan of Truman either...

My regards,

Widewing
My regards,

Widewing

YGBSM. Retired Member of Aces High Trainer Corps, Past President of the DFC, retired from flying as Tredlite.

Offline Widewing

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How much extra hp could the R-2800 deliver?
« Reply #13 on: January 17, 2008, 11:14:17 PM »
Quote
Originally posted by AquaShrimp
I read that an inline-engined version of the P47 (using a chrysler engine) achieved 490mph in level flight.


No, the XP-47H was a dog. I don't think its Chrysler engine ever made full rated power. I recall that it was slower than the standard P-47D-10, never managing better that 415 mph on test flights.

My regards,

Widewing
My regards,

Widewing

YGBSM. Retired Member of Aces High Trainer Corps, Past President of the DFC, retired from flying as Tredlite.

Offline skaltura

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How much extra hp could the R-2800 deliver?
« Reply #14 on: January 18, 2008, 03:56:13 AM »
"Oh, and I'm not a big fan of Truman either..."

Why so?