Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: ramzey on December 15, 2004, 10:58:47 AM
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I know its fighters build for 2 diferent purposes but if we talk about ability to dive spit beat thinderbolt in dive.
Tests done by RAF in 1943 proof spit can go Mach 0.89 in dive , P47 only M 0.83. Also P47 has trouble manuvering in dive.
Less manuverable P47 is a brick compared to spit, im right?
What for was add dive brakes in p47?
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Dive from 35K, the P47 will hit the deck much quicker than a Spitty.
However, Spitty, accelerating slower, eventually aquired enormous speed and got away with it.
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I've always been rather intrigued by the account in Shaw's book attributed to Robert Johnson where he talks about fighting a Spit IX in a P-47C model.
I don't think there would be any way to replicate that in AH, unless the P-47 literally "extended" out about 2k yards before beginning the dive and the Spit didn't try to cut the corner on the dive and zoom.
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The spit has a slightly larger terminal velosity than the jugs, but the jug will accelerate and reach it much faster.
The P47 from all the accounts I've read had good controls response till it reached the compresion. It didn't suffer from heavy ailrons like the spit or the stick kicking into the belly like the P51, although eventually the elevator got so heavy that pilots used both hands and pushed with their legs to get it out of the dive.
The major problem in dives was that acceleration was so fast that before the pilot notcied, he was already compressing. I think the dive flap, simmilar to the P38's, was supposed to help with pulling up from the dive. But I might be wrong about that one.
Bozon
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109's and 190's could not dive from harm's way when meeting jugs, but they'd leave the Spit far behind.
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It really stood out in Johnson's book when he mentioned playing with the Spit in his Jug.
First time, he kinda surprised the Spit driver but using his roll rate to stick with the guy. Got some E built up and zoom climbed away from the Spit, then when his E was used up, the Spit motored on up and past him.
Later, after the paddle blade prop was installed in his Jug, he was able to reverse those results....he says he pulled away from the Spit IX in a climb. He didn't say, but I bet he was in "Lucky" when that happened, since it was the hotrodded Jug he mentioned in his interview with Widewing.
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Wasn't it him who said:
"The P47 had to dive well, it surely wouldn't climb"?
I'll try to find it.
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I remember a remark about "in the Jug, you just let the nose drop and it dove like crazy, but you had to fly the Spitfire down."
Also, Gabreski, who flew both planes in combat said the Spitfire climbed well, but "it was so light, it just wouldn't dive"....or something very close to that.
I was thinking it was Zemke who said, when someone commented on the outstanding dive performance of the Jug vs LW fighters....."it ought to dive, it sure as hell won't climb!".....but, after 30+ years of reading this stuff my memory may not be 100% correct. :D
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Originally posted by eddiek
It really stood out in Johnson's book when he mentioned playing with the Spit in his Jug.
First time, he kinda surprised the Spit driver but using his roll rate to stick with the guy. Got some E built up and zoom climbed away from the Spit, then when his E was used up, the Spit motored on up and past him.
Later, after the paddle blade prop was installed in his Jug, he was able to reverse those results....he says he pulled away from the Spit IX in a climb. He didn't say, but I bet he was in "Lucky" when that happened, since it was the hotrodded Jug he mentioned in his interview with Widewing.
He surprised the Spit because he started with an altitude advantage.
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P47 performance is directly related to engine thrust. Lets not forget, that a souped-up P47 hit 504mph in July 1944 in level flight.
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Originally posted by Angus
Wasn't it him who said:
"The P47 had to dive well, it surely wouldn't climb"?
I'll try to find it.
Don Blakeslee, 4th FG. Those people never liked the 47, because they started out on spits.
- oldman
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"The following episode, found in Thunderbolt! by the World War II USAAF ace Robert S. Johnson, is one of the best examples available of the use of energy tactics (diving extension/pitch-back) to defeat a double-superior opponent. The encounter described is a mock combat engagement over England between Johnson (P-47C) and an unidentified RAF pilot in a new Spitfire IX. the Spitfire had about a 25 percent better power loading and nearly a 25 percent lower wing loading. The Thunderbolt's only performance advantages were faster top speed, greater acceleration in a dive (because of the P-47's heavier weight and higher density), and better roll performance.
I opened the throttle full and the Thunderbolt forged ahead. A moment later exhaust smoke poured from the Spit as the pilot came after me. He couldn't make it; the big Jug had a definite speed advantage. I grinned happily; I'd heard so much about this airplane that I really wanted to show the Thunderbolt to her pilot. The Jug kept pulling away from the Spitfire; suddenly I hauled back on the stick and lifted the nose. The Thunderbolt zoomed upward, soaring into the cloud-flecked sky. I looked out and back; the Spit was straining to match me, and barely able to hold his position.
But my advantage was only the zoom--once in steady climb, he had me. I gaped as smoke poured from the exhausts and the Spitfire shot past me as if I were standing still. Could that plane CLIMB! He tore upward in a climb I couldn't match with the Jug. Now it was his turn; the broad elliptical wings rolled, swung around, and the Spit screamed in, hell-bent on chewing me up.
This was going to be fun. I knew he could turn inside the heavy Thunderbolt; if I attempted to hold a tight turn, the Spitfire would slip right inside me. I knew also, that he could easily outclimb my fighter. I stayed out of those sucker traps. First rule in this kind of fight: don't fight the way your opponent fights best. No sharp turns; don't climb; keep him at your own level.
We were at 5,000 feet, the Spitfire skidding around hard and coming in on my tail. No use turning; he'd whip right inside me as if I were a truck loaded with cement, and snap out in firing position. Well, I had a few tricks too. The P-47 was faster, and I threw the ship into a roll. Right here I had him. The Jug could outroll any plane in the air, bar none. With my speed, roll was my only advantage, and I made full use of the manner in which the Thunderbolt could roll. I kicked the Jug into a wicked left roll, horizon spinning crazily, once, twice, into a third. As he turned to the left to follow, I tramped down on the right rudder, banged the stick over to the right. Around and around we went, left, right, left, right. I could whip through better than two rolls before the Spitfire even completed his first. And this killed his ability to turn inside me. I refused to turn. Every time he tried to follow me in a roll, I flashed away to the opposite side, opening the gap between our planes.
Then I played the trump. The Spitfire was clawing wildly through the air, trying to follow me in a roll, when I dropped the nose. The Thunderbolt howled and ran for earth. Barely had the Spitfire started to follow--and I was a long way ahead of him by now--when I jerked back on the stick and threw the Jug into a zoom climb. In a straight or climbing turn, the British ship had the advantage. But coming out of a dive, there's not a British or German fighter than can come close to a Thunderbolt rushing upward in a zoom. Before the Spit pilot knew what had happened, I was high above him, and the Thunderbolt hammering around. And that was it--in the next few moments the Spitfire flier was amazed to see a less-maneuverable slower-climbing Thunderbolt rushing straight at him, eight guns pointing at his cockpit." (Fighter Combat, Robert Shaw)
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I'm with Milo on this one.
First, Johnson suddenly started the 'prank' and caught the Spit pilot by surprise. He took the initiative, and it is likely the Spit pilot did not know Johnson started a 'game' until he finalyy understood and decided to play along.
If you read the article closely enough, you'll notice that were it real combat, there would be more than one opportunity for the Spit9 to get a close-range open firing solution on the P-47.
Ofcourse, considering that this is the P-47 we're talking about, no disrespect in Johnson's skills at all. He managed an overshoot and caught the rear end of the Spit. This is definately not an easy thing to for sure.
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Originally posted by MiloMorai
He surprised the Spit because he started with an altitude advantage.
Actually Milo, Bob and the Spitfire were flying in formation (same speed) when Bob firewalled the Jug and accelerated away. See pages 199-200 of 'Thunderbolt".
My regards,
Widewing
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It's also Martin Caiden writing. And while I like Caiden's work, you have to keep the "Caiden filter" on high as he tends to overdo it a bit sometimes.
Dan/Slack
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Spits ok if you want to play arround. If you want to win a war bring a thunderbolt.
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Originally posted by SunTracker
P47 performance is directly related to engine thrust. Lets not forget, that a souped-up P47 hit 504mph in July 1944 in level flight.
That was the XP-47J, fitted with a 2,800 hp C-series R-2800 engine. This prototype was abandoned for Republic's 3,600 hp XP-72A.
Designed specifically to defeat the Fw 190, the XP-47J was Republic's effort at an "air superiority" fighter. Weight was reduced (so was the armament, reduced from 8 to 6 guns) 9,663 pounds (empty), power was increased by 800 hp, and a "high activity" paddle-blade prop was employed to more efficiently use the added power.
Factory test data reveals a climb rate of 4,900 fpm at sea level, and a startling 4,400 fpm climb rate at 20,000 feet. The XP-47J, flying with full internal fuel and ballast installed to simulate a full ammo load, reached 30,000 feet in 6 minutes, 45 seconds!
This prototype was fully fitted for combat, it was not stripped down. It included guns, ammo ballast, armor and a full set of radios. It was not, however, fitted with underwing pylons (as were no other P-47s when the XP-47J rolled out in November of 1943).
Ultimately, the engine and prop combination were fitted to a P-47C-5, which exceeded 480 mph during test runs. Eventually, the data from this program resulted in the P-47M, the fastest, best climbing P-47 to see combat duty in the war. There were plenty of hotrodded Jugs prior to the M model as P&W tech reps had been assisting crew chiefs in tuning the R-2800s for sustained over-boost use. During 1943, both Republic and Pratt & Whitney had done extensive durability testing with R-2800 engines over-boosted to as much as 3,600 hp. Later C-series engines were tested at boost settings producing 3,600+ hp for 250 hours without failure. They determined that while engine life was greatly shortened, there was little risk of catastrophic engine failure from over-boosting to 72 in/Hg for short durations. Consequently, many P-47s were rigged in the field (primary mods being to the wastegates) for this power output. Johnson stated without ambiguity, that his P-47 could pull 72" MAP, without water injection! Johnson related that crew chief Pappy Gould and a P&W rep named Ron Dempsey explained that they could rig Johnson's Jug for 72" MAP with a kit fabricated locally. Johnson asked what the benefit would be and he was told that he could expect to see major increases in climb, acceleration and speed. Johnson said, "go ahead". Johnson stated that the result was a 470 mph P-47D-5 (serial 42-8561, named "Lucky"). Johnson's P-47 was certainly not the only Jug to be so modified. According to Gould, that most, if not all P-47s in the 61st FS of the 56th FG was field modified in the same way.
What many don't realize or understand was that unauthorized field modifications were the rule, not the exception, throughout the AAF. Modified canopys (some P-47s razorbacks also sported Malcolm Hoods), Spitfire mirrors, custom fuel blends (almost all fuels were blended locally), modified wastegates and turbo regulators to name just a few. Johnson's P-47 had every seam sanded smooth, and gaps filled with autobody filler. Then it was polished as smooth as glass. Pappy Gould described some of his own tricks, which included gasket-matching, smoothing and polishing of exhaust ports and stacks. Exercising extreme care in matching and aligning intake plumbing. Redundent sealing throughout the turbo ducting. Rejetting carbs and carefully cleaning up venturis. Reshaping cylinder baffling to improve engine cooling. Almost no aircraft remained truly "factory stock".
My regards,
Widewing
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Originally posted by Guppy35
It's also Martin Caiden writing. And while I like Caiden's work, you have to keep the "Caiden filter" on high as he tends to overdo it a bit sometimes.
Dan/Slack
Long after Caiden died, Bob re-released his book, with added material. You don't need a "Caiden filter" in this case, you merely had to know Bob, and I knew him fairly well. I have five hours of interviews with Johnson, done several months before his death, some of which I transcribed and posted on this BBS about 3 years ago. EddieK is has been eagerly waiting for me to transcribe the rest, but there's a lot to do.
Caiden was no more than an editor, Johnson insisted that the story be told as Johnson wrote it. This is far different than Caiden's Fork-tailed Devil, where he wrote most of the book. However, P-38 pilot Art Heiden (quoted heavily in the last chapter) says that Caiden did quote him accurately. Caiden had a reputation for creative writing, but "Thunderbolt" is not one of those works.
My regards,
Widewing
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Originally posted by Widewing
Long after Caiden died, Bob re-released his book, with added material. You don't need a "Caiden filter" in this case, you merely had to know Bob, and I knew him fairly well. I have five hours of interviews with Johnson, done several months before his death, some of which I transcribed and posted on this BBS about 3 years ago. EddieK is has been eagerly waiting for me to transcribe the rest, but there's a lot to do.
Caiden was no more than an editor, Johnson insisted that the story be told as Johnson wrote it. This is far different than Caiden's Fork-tailed Devil, where he wrote most of the book. However, P-38 pilot Art Heiden (quoted heavily in the last chapter) says that Caiden did quote him accurately. Caiden had a reputation for creative writing, but "Thunderbolt" is not one of those works.
My regards,
Widewing
Glad to hear it Widewing, as Fork Tailed Devil, Flying Forts, The Ragged Rugged Warriors (Think that was the title) etc all seemed to take more then their fair share of liberties with the 'truth' :)
My Caiden favorite was "Everything but the Flak" about the recovery, restoration and ferry flight of the 3 B17s for the making of the movie "The War Lover" that starred Steve McQueen and Robert Wagner.
Former RAF Buffalo pilot John Crewsden played a prominant part in that book as well as in the movie doing some amazing work in the B17
Dan/Slack
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Right WW. It has been many years since reading that passage. Iirc it all started with a 'bull session' of some sort and remembered that BJ pulled a fast one on the Spit pilot.
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Hi Widewing,
>Johnson stated that the result was a 470 mph P-47D-5 (serial 42-8561, named "Lucky").
You are aware of course that I consider that figure the result of instrument errors.
However, generally I consider P-47 performance under-researched, and I'm currently looking for power charts. Do you happen to have anything on that matter? Just as for the P-38, I think the P-47's turbocharging makes for a more complex power curve than indicated in the Vought comparison documentation. (That also features the F4U-3 that uses a R-2800C, too, and they actually provide power graphs for different boost pressures up to 73" Hg, but as I'm afraid in rather simplistic form only.)
Regards,
Henning (HoHun)
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Bring this P-47M thing you speak of to AH! =) We can even perk it if we have to... But it would be sweet!
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Originally posted by JG14_Josf
We were at 5,000 feet, the Spitfire skidding around hard and coming in on my tail. No use turning; he'd whip right inside me as if I were a truck loaded with cement, and snap out in firing position. Well, I had a few tricks too. The P-47 was faster, and I threw the ship into a roll. Right here I had him. The Jug could outroll any plane in the air, bar none. With my speed, roll was my only advantage, and I made full use of the manner in which the Thunderbolt could roll. I kicked the Jug into a wicked left roll, horizon spinning crazily, once, twice, into a third. As he turned to the left to follow, I tramped down on the right rudder, banged the stick over to the right. Around and around we went, left, right, left, right. I could whip through better than two rolls before the Spitfire even completed his first. And this killed his ability to turn inside me. I refused to turn. Every time he tried to follow me in a roll, I flashed away to the opposite side, opening the gap between our planes.
Then I played the trump. The Spitfire was clawing wildly through the air, trying to follow me in a roll, when I dropped the nose. The Thunderbolt howled and ran for earth. Barely had the Spitfire started to follow--and I was a long way ahead of him by now--when I jerked back on the stick and threw the Jug into a zoom climb. In a straight or climbing turn, the British ship had the advantage. But coming out of a dive, there's not a British or German fighter than can come close to a Thunderbolt rushing upward in a zoom. Before the Spit pilot knew what had happened, I was high above him, and the Thunderbolt hammering around. And that was it--in the next few moments the Spitfire flier was amazed to see a less-maneuverable slower-climbing Thunderbolt rushing straight at him, eight guns pointing at his cockpit." (Fighter Combat, Robert Shaw)
This is the part that intrigues me. He doesn't say exactly how far the "gap" was between them when he went up into the zoom climb and (I assume) a hammerhead to come back around on the Spit that was just beginning his zoom underneath.
I simply don't see how this is possible, given my experience with both planes in AH. At the "best" that would end up in a joust that both planes would likely lose, at the "worst" the Spit would easily nail the Jug at the top of its zoom.
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In rl the spit wouldn't hang on its prop trying to spray and pray. Simply staying beyond 4 or 500 meters was enough to be 'out of gun range'. As the jug went up the spit realized if he followed that he would not close the gap and get a gun solution before that the jug would be coming right back at him and he didn't want any of that.
The jug came back down closing the gap faster then the spit could get out of the way.
In a game situation there's nothing to loose by following the jug up and hanging on your prop throwing out hizookas as fast as a televangelist throws out viewer prayer requests after removing the checks...
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Looks like the Spit pilot did a big mistake by trying to follow the roll and scissors. Maybe he should have throttled back and just watched.
That's what I do when the 190 guys play that on me ...but in AH...:D
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Originally posted by Widewing
Long after Caiden died, Bob re-released his book, with added material.
Do you still have the reference for where we can get this book, Widewing? I know you posted it once, long ago and far away, and I was too ignorant to write it down.
- oldman
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You don't throttle back and watch a scissor, the jug would just level, go nose down and accelerate away. You climb when faced with a scissor so that you conserve your energy.
Then if the jug tries to run you drop back in.
The reason scissors work so well in online games is because the attacker is desperate for the kill. In AH if don't get the kill in the scissor and zoom up the other 5 friendlies will jump in and finish the guy off so you need to push for the kill in those situations.
In the spit/47 match up real guns weren't involved so the spit probably tried to force the shot rather then climbing to re-position. Once the jug got separation he went nose down, built up his speed and zooms. The spit couldn't do anything at this point except catch bullets.
The 190 in AH accellerates faster and has a faster top speed then either the spit 5 or spit 9. Try chopping throttle and watching my 190 and I will soon be above you just like that jug...
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Oh, forgot, they had alt.
Otherwise, take a barrel roll above, hehe.
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Sorry if I have bugged you to death about getting that stuff transcribed. I know it is a time consuming process to get stuff typed up as you listen to a tape recording of an interview with a vet. I am having the same problem myself, getting an almost 4-hour interview with a Jug pilot transcribed into text. Real life stuff steps in and you have to put the project on hold and before you know it, 6 months or a year has passed before you get back to it.
FWIW, the pilot I visited with (still visit with from time to time) flew Jugs from the D20 onward up to the P-47N (he was scheduled to be redeployed to the Pacific after V-E Day and was stateside, on his way to a new base to train for the invasion of Japan when V-J Day arrived), and like Johnson said, it was a standard procedure for Jugs to be worked over at the depot level before dispersion to the squadrons. His comments about the subject were "Son, when your life is on the line, you use any and every edge you have. Coming back alive, or even surviving getting shot down, was sure as hell more inviting than getting cannon shells in the cockpit with you. The P-47 was a fine aircraft as delivered from the states, but without the mods we did, they were not up to snuff with what the Luftwaffe was throwing at us. And those pilots were damn good! Without the things we did to our planes, we would have gotten our tulips shot off. We had Republic field reps there all the time, telling us what to do to make the planes better. You won't find any of it in any logs or anything like that, because it was not "officially" condoned. Oh, the brass knew what we were doing, but they looked the other way because if they cracked down on us and made us fly stock fighters, we were gonna get our tulips handed to us and then they would have to face the papers and try to explain why we were losing so many pilots."
His own P-47D-20 was worked over by his crewchief (before military life, a mechanical engineering degree recipient) and it pulled 80" MAP routinely and without engine damage or failure.
I asked him what the highest level flight speed he ever got out of her was, and he replied "310 indicated at about 30-31,000 feet was the most I ever got out of that plane", then he laughed and said that in the Jug. I forgot the correction factor for speed at alts, but I believe that performance was close to or rivalled that of Johnson's plane(s).
Flight Journal magazine (I know, a magazine) has a pilot's account of his P-47 engine being modded by the crewchief to pull 100" MAP, but only in extreme emergency and only for a very brief period of time (about one minute). The pilot used it in combat to escape several FW-190's on the deck by climbing away from them, but I know that pilot anecdotes are not concrete evidence.
I have rambled far too long, I better close before the flame wars get started in this thread, too.
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310ias at 30,000 feet is 496mph. Pretty fast!
Heres the calculator I used http://www.csgnetwork.com/tasinfocalc.html
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unfortunately, no sim is ever going to model a razor back with a paddle blade prop pulling 72" preassure. Now, that's a monster for you.
Bozon
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Hi Suntracker,
>310ias at 30,000 feet is 496mph. Pretty fast!
Hm, that calculator apparently uses a rule of thumb to calculate true air speed.
According to my calculation, 310 mph IAS at 30000 feet is 506 mph TAS, or Mach 0.75.
That's neglecting both calibration and compressibility error - I'd expect the true air speed to have been considerably lower than Mach 0.75 at that IAS reading.
Regards,
Henning (HoHun)
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Hi Bozon,
>unfortunately, no sim is ever going to model a razor back with a paddle blade prop pulling 72" preassure. Now, that's a monster for you.
Get X-Plane and model your own :-) No guns in that simulation, though.
Regards,
Henning (HoHun)
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Originally posted by bozon
unfortunately, no sim is ever going to model a razor back with a paddle blade prop pulling 72" preassure. Now, that's a monster for you.
Bozon
Why don't we see if Nomde could talk HT into modelling this and the other feild mods that were the rule, but make them perked rides?