Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: AquaShrimp on January 08, 2008, 01:43:10 AM
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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?
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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.
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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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the RAF used to re-mill all the Pacard merlin engines when they were shipped over. got an extra 300BHp out of it.
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I've read about some Mustang pilots having their Merlins modified to pull 79 inches of manifold pressure.
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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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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 (http://www.spitfireperformance.com/)
You will find the P-47B/C/D/M and N test as well as pretty much everything else you could ask for.
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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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I read on an air-racing board (while reading about a radial engined P-51) that the R-2800 could produce 4000 hp.
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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
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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.
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I read that an inline-engined version of the P47 (using a chrysler engine) achieved 490mph in level flight.
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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
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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
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"Oh, and I'm not a big fan of Truman either..."
Why so?
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I remember it mentioned several times that the 56th were over boosting their jugs. There is a famous quote by Johnson claiming that his plane could reach 72" manifold pressure - which would be something like the N's engine but on a much lighter plane.
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Originally posted by skaltura
"Oh, and I'm not a big fan of Truman either..."
Why so?
At the outset, let's give him credit where it was due. The Marshal Plan, pushing for civil rights (including integrating the Armed Services), his handling of the Berlin Blockade, and the recognition of Israel. All major accomplishments and all historic in result.
Some of his proposed social programs were little more than open socialism. His gutting of the military with small, very tight defense budgets would haunt us when the Korean War broke out. His almost timid approach to fighting that war certainly emboldened the Soviets and Chinese. Truman was very much like Wilson in his approach to international affairs. I preferred TR's method of negotiating while cleaning your weapon... Wilson's League of Nations failed miserably. Truman was a vigorous supporter of the United Nations, which is now generally looked at as largely corrupt and generally incompetent by many Americans.
What bothers me most about Truman was his association with Tom Pendergast and the blatant election fraud associated with his Senate run of 1934. Today, that election would have overturned and indictments would be flying around like confetti. His association with Larry Bell was scandalous. Truman's cronies funneled a great deal of defense money to Bell, when far more qualified contractors were warned not to step on Bell's shoes. North American Aviation stepped on them anyway.
Truman's behavior often reflected his willingness to accept help from decidedly shady characters (not that this is any different from the Clinton and current Bush administrations). This was evident throughout his career.
Anyway, those are some reasons why I don't consider Truman a particularly good President.
My regards,
Widewing
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Perhaps a smaller nationīs citizenīs view on TRīs gunpoint negotiation tactics would differ from yours...E.g. we Finns had less than pleasant experiences on those tactics in the hands of Molotov and Stalin...
And by our standards American election system feels highly corrupt and undemocratic (such as the need to specifically register to vote, here we get voting rights automatically on reaching 18) as well. But thatīs OT!
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Originally posted by skaltura
Perhaps a smaller nationīs citizenīs view on TRīs gunpoint negotiation tactics would differ from yours...E.g. we Finns had less than pleasant experiences on those tactics in the hands of Molotov and Stalin...
And by our standards American election system feels highly corrupt and undemocratic (such as the need to specifically register to vote, here we get voting rights automatically on reaching 18) as well. But thatīs OT!
Remember, TR negotiated the end of war between Russia and Japan. His maneuverings as Under-Secretary of the Navy pretty much was responsible for ejecting Spain out of the western hemisphere. TR was a strong believer of the Monroe Doctrine and Manifest Destiny, and even expanded upon it. He was determined to keep European powers out of the western hemisphere, and he was successful. That said, Roosevelt was careful to cultivate good relations with virtually every European nation.
Roosevelt was nothing like Stalin or Molotov. He was the antithesis of these men. He was a populist President, who battled big business for the well being of the common man. He was the worlds first true environmentalist, determined to preserve as much wild country as possible. America's great national park system would not exist except for Roosevelt. Find a good biography of TR. You'll discover why many historians list America's greatest Presidents as Washington, Lincoln and Roosevelt.
As to our requirements to vote; you have to be a citizen and at least 18 years of age. Registration is where you establish your citizenship via proper documentation.
My regards,
Widewing
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Speaking of Manifest Destiny, believing in that is in my book less than positive aspect for its spirit is responsible for the most complete genocide ever (=that of the Indians), in terms of peoples destroyed.
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I disagree, skaltura. If you go back to the early Middle Ages, classical antiquity and the biblical period you'll find PLENTY of examples of entire cultures being wholly exterminated.
Just look at Britain. The Celtic peoples came in and displaced the original native inhabitants. Then Romans effectively drove them out of significant parts of the island into the areas that are now Scotland, Ireland and Wales. The Saxons then destroyed or displaced the Romano-Britons to those same areas, before THEMSELVES being destroyed or assimilated by the Normans between the 11th and 12th centuries. This is, of course, excluding the attempt by the Danes to establish hegemony over Britain before the Danelaw was forcibly ended.
It's the nature of humanity. People like to wag their fingers at the American treatment of the natives here (actually, look at what the Spanish did in South America in the 17th Century. Can't blame THAT on Monroe) but the simple FACT is that human beings have been eradicating other cultures since the first caveman picked up a rock and bashed his neighbor's head in.
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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.
I was thinking about this, and in retrospect think that referring to Bodie as lying was a bit strong. Mistaking, yes, but I doubt he would deliberately lie. He is, if nothing else, stubborn.
A little research (thanks to Tony Williams) shows that the Tempest could shoot a total weight of 6.5 kilograms per second. The P-47 could put out 4.85 kilograms of lead every second.
However, the P-47 fired 100 rounds to the Tempest's 50 (per second). Therein is found the argument that the USAAF/USAF used to justify MG only armament. They would argue that by firing twice as many rounds, they are twice as likely to score hits. Inasmuch as fighters were not especially resistant to .50 cal API, they thought this to be adequate. Conversely, the US Navy countered this argument by showing that since a 20mm round did at least 4 times as much damage, 50% less hits would still result in twice as much damage to the enemy aircraft. Thus, by late 1944, the Navy wanted cannons on all new fighter designs.
Meanwhile, the USAAF/USAF maintained the 6 gun .50 cal armament on their fighters until mid way through the Korean war, when their thinking began to change. When it proved difficult for the F-86 to knock down the simple, but tough little MiG-15s, pilots began seriously questioning the Browning .50 cal MG as a viable air to air weapon. Their uproar was substantial. Eventually, the F-86 was armed with 20mm cannons (F-86H). Before the first F-86H ever flew, the Navy already had its navalized version, the FJ-2 (very similar to the F-86E) in limited squadron service, armed with four 20mm cannon (the F-86 was given production priority by the Pentagon, so Navy needs took a back seat). At the time, North American asked the USAF to consider the 20mm cannon to standardize production with Navy contracts, reducing costs for both services. North American stated that the production line could be tooled for cannon installation without interrupting F-86 deliveries. Air Force Brass refused, claiming that they would have to spend too much effort in setting up the required logistics. Oh, and the .50 cal was still good enough (paraphrased).
Personally, I think the overwhelming reason that the USAF didn't switch to 20mm cannons at that time had less to do with logistics than with good old inter-service rivalry. If the Navy said black, the Air Force, in a Pavlov's dog reaction, would say white. That "conditional reflex" continues to this day, albeit that budget limitations have fostered greater inter-service cooperation these days out of necessity.
History is often stranger than fiction.. ;)
A friend once suggested a novel way to reduce defense spending. His theory was that the budget should be proportional to the number of functioning brain cells within the Pentagon. However, this idea was flawed in that it would leave only enough money to arm the Boy Scouts with wrist-rocket sling shots.. Insufficient to defend the free world.
My regards,
Widewing
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:rofl
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According to a study done on aerial combat in WW2, 50cal aerial ammunition did its damage mainly by igniting either the ammunition stores, or fuel tanks on enemy planes. API (armor piercing incendiary) was found to be the most effective, while ball was the least effective.
I can see how the Mig-15 would be hard to destroy, all of its ammunition is in the nose. I'm not sure where the fuel tanks are though.
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The 50's do fine ripping structures to pieces as far as I know.
It is a fast and mean bullet.
(and noisy)
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Originally posted by Widewing
the US Navy countered this argument by showing that since a 20mm round did at least 4 times as much damage, 50% less hits would still result in twice as much damage to the enemy aircraft
Similarly the VVS determined that the Yak9T was more effective than the Yak9D.
Whilst this was biased by the T's capabiliies against bombers as well as fighters
VVS combat statistics had it that an average of 31 NS-37mm rounds were required to down an enemy aircraft against an average of 147 20mm Shvak rounds.