Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Arlo on November 28, 2003, 07:39:19 PM
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Has an intimidating effect on most hardcore Luftwaffe fans. :D
WW ... how DARE you even come close to suggesting that the Luftwaffe was beaten by better ANYTHING ... be it plane or pilot! Well ... you may get away with suggesting logistics and production. ShruG :lol
One thing's for sure .... the more real life WWII fighter pilots pass on .... the more experts who know what really happened are born. :eek:
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SPEW !
LOL
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Hi Arlo,
>One thing's for sure .... the more real life WWII fighter pilots pass on .... the more experts who know what really happened are born. :eek:
Afraid to name horse and rider, Arlo?
Here's the Johnson quote:
CCJ: 72 inches!? Did you ever take note of your airspeed during one of those runs?
RSJ: Of course.
CCJ: And....... how fast did it go?
RSJ: I've seen just over 300 at altitude.
CCJ: 300 indicated?
RSJ: Yes.
CCJ: What was your altitude?
RSJ: I guess it was right around 32,000 feet.
CCJ: Geez, that’s well over 450 mph!
RSJ: Oh, I figure closer to 470.
My comments:
- 72" Hg at 32000 ft are unobtainable by the P-47D judging from the reference data both Widewing and I have found. In fact, even 64" Hg are only obtainable up to around 27000 - 28000 ft.
- 300 mph CAS at 32000 ft don't equal 470 mph TAS as stated by Johnson, but (including compressibility correction) a stunning 489 mph. That's well above the top speeds of even the P-47M and N as quoted by Widewing, and matches XP-47J performance.
Quite obviously, Johnson made a mistake recalling the exact altitude at which his P-47 reached its top speed.
I don't think this a particularly exciting observation. If it harms your general warm-and-fuzzy feeling about the P-47 - well, not my fault, really.
Regards,
Henning (HoHun)
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Real-life rarely matches theoreticals.
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Originally posted by HoHun
Afraid to name horse and rider, Arlo?
*ShruG* If you feel it applies feel free to be offended. As for the rest, you can pull out every chart, book, reference, comic and trading card you got but you still weren't there and he was. I'm sure you can dig up some first hand quotes from the Luftwaffe vantage point and fire them back. Then someone who finds them biased can talk about how biased and mistaken they were in return. Of course ... there's only one side that really has a reason to have sour grapes about the past. ;)
Keep crunching! :D
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Hi Arlo,
>*ShruG* If you feel it applies feel free to be offended. As for the rest, you can pull out every chart, book, reference, comic and trading card you got but you still weren't there and he was.
So what? I'm still right, and he's still wrong.
Your comments are ignorant, and your intent is character assasination.
You're a coward, Arlo. You're throwing dirt because you can't compete on an intellectual level.
If you're interested in the truth, write a polite email to Hitech and ask him about his opinion on a 470 mph TAS @ 32000 ft P-47D.
If you're interested in sustaining your self-deception, don't write to Hitech but keep writing insulting posts here.
I'm going to put you on my ignore filter now, so if you actually write to Hitech, hear his opinion and want to apologize, you're going to have to forward your apology via a third person.
(Adding that paragraph might have been a waste of time, but if you should be a decent guy after all, I'm always ready to give you a second chance.)
Henning (HoHun)
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Ignore list? How nice of you. Then you won't be seeing the following:
Give me a second chance? You're the anal fruitcake with a Third Reich axe to grind. And your response is indicative of someone who needs to get a life. ;)
Have a nice day. :D
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For the "new" release of Butch Cassidy and the Sundance Kid they interviewed all the principle actors and the director. Paul Newman prefaced his interview by saying he got together with his flight crew from WWII recently, and NONE of them could agree on ANYTHING that happened during the war.
Memory is like that. I've run into that myself chatting with some of my old cohorts from merely twenty years ago.
The point is don't necessarily take everything said by WWII vets who "were there" at face value. Even when I get my dad talking I keep in mind the distance back he is recalling his stories. This doesn't mean they're lying, it means memory isn't an impartial observer.
Just my two centavos.
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I am not even going to pretend to take sides in this arguement. The last time I joined someone elses arguement I couldn't get out. So I will just post this and let everyone draw their own conclusions.
BTW, this document is from the Vought archives. Manifold pressures and speeds are listed. The F4U-3 used the same Turbo Superchargers and the same R2800C block as the P-47D. The F4U-1 did have a slightly lower Cdo than the P-47. At 68" of MAP producing 2800HP it reached 486MPH at 30K. At 73"MAP it reached 3,000HP and 487MPH at 27K but more importantly at 63" and 2600HP it hit 480MPH at 32,000FT.
http://mywebpages.comcast.net/markw4/F4U-3MSW.pdf
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Not the point, Puck.
Henning's strongly implied viewpoint that his collection and interpretation of charts, graphs and data relating to his favorite aircraft (and perhaps, to some degree, of their opposing aircraft) constitutes his being more of an authority on any and all WWII aircraft (or even just his favorite ones) than the pilots who flew/flew against them ... to the point of disregarding statements made by those pilots, out of hand, when they don't support his own prejudiced assessment ... reflects both bias and delusion. And his responses in this thread alone reveal a defensiveness that appears to be motivated by an insecurity that he'd probably be hard-pressed to admit.
It's generally a dead give-away when the "expert viewpoint" by a second or third-hand "authority" in one of these threads attack the sources of the other second or third-hand "authority" without the slightest hint of the ability to concede to any portion of the other party's viewpoint.
In other words .... I'm as impressed with Henning's "expertise" in pulling up charts and quoting statistical data as I am with anyone else's. Which is several shades shy of my being impressed by a conversation with a real WWII veteran pilot describing his experiences to the best of his ability.
And if Henning ... or anyone else .... can't handle that .... then too bad. I hope they get over it but I won't be too distraught if they don't. :D
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In the P47D training film, an overspeed light for the turbo-charger would come on if the engine was at too high of a speed above a certain altitude.
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Hi F4UDOA,
Thanks for presenting facts! :-)
The document you posted shows an R-2800 engine that can't obtain 72" Hg at 32000 ft, confirming my point.
The F4U-3's airframe his less drag than the P-47D's. From another page of the same document, the P-47D at sea level achieves 354 mph @ 2600 HP, while the F4U-3 achieves 378 mph @ 2800 HP, which translates into 368 mph at equivalent power to the P-47D.
The P-47D's extra drag is enough to prevent it from reaching 470 mph @ 32500 ft even with the same engine as the F4U-3, again confirming my point.
Regards,
Henning (HoHun)
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I, for one, would like to see the official, verified, scientifically-modeled, unbiased, confirmed by former German scientists brought over to assist the U.S. with it's rocket program after the war wind-tunnel comparisons of the two airframes mentioned to see how much horsepower the F4U had over the P-47 due to a better streamlined airframe. But since Henning has conveniently filtered me I suppose it's up to someone else to challenge him to produce or stuff a sock in it.
Actually .... until Henning (or anyone else, for that matter) can confirm that he, himself has tested the envelope in these planes, I could really care less how much paper he does or doesn't throw at an argument ... especially when he picks and chooses what published opinions (of the pilots who were really there) are accurate and which "were mistaken" (based on Henning's unimpeachable expertise). I can pick and choose myownself without all the superfluous addenda thrown in "to back it up." Which is all this thread variant was about. ;) :D
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A couple of points.
When Johnson said during my interview that he saw 300 mph IAS at 32,000 ft, I immediately compared that to the P-38 (which I been extensively researching). At 30k and 300 mph IAS, the P-38 would have been well into compressibility. Estimating in my mind, I figured that at 32k, 300 mph IAS is about 455 mph. I responded to Bob with "That's well above 450 mph". Bob then said, "Closer to 470."
I thought a speed just above 450 mph was reasonable, and I still think that it is. And believe me, there was nothing that Johnson was going to encounter in December of 1943 that could get within 60 mph of his Jug at altitude anyway.
After reviewing various data sheets for the R-2800-21 and -59, as well as power and speed charts for the above, I conclude that Henning isn't really out of line here, 32,000 feet is really pushing the limits to pull 72" of MAP with a "B" series engine and related turbo.
When I examine the power curve for the P-47M-1-RE, I see that it could reach 475 mph at 32,600 feet, pulling 72" Hg. However, the P-47M used the -57 "C" series engine and the more efficient CH-3 turbo. This turbo provided greater boost pressure without overspeeding. According to G.E., the C-21 and C-23 turbos suffer serious efficiency problems at 22,000 RPM, as well as great risk of overheating, which will eventually cause the lubricating oil to coke, which in turn works like a lapping compound that will rapidly destroy the bearings. This is why the turbos (C-21 and C-23)were regulated to 18,250 RPM in normal use, it provided a adequate cushion for limited overspeed. The Turbo impeller/compressor assembly could handle rotational speeds up to 26,000 RPM, but due to the backpressure caused by their inherent inefficiency, boost pressure would drop dramatically, and temperature would rise dangerously within the turbo housing. This would eventually lead to heat related failure as described above. Catastrophic failure could seriously damage the airplane and cause it to become unflyable. It is interesting to note that Republic did design in more than enough duct capacity for even the CH-3 turbo.
Now about comparing drag between the P-47D/N and F4U-3. In terms of drag coefficient, the P-47D-25 thru M is lower than the the F4U-1D. The Jug comes in at .0235 and the Corsair at .0267. The F4U-3 was built from the F4U-1A, which didn't have the rocket stubs. However, the F4U-3 did incorporate a large intake scoop under the fuselage (as engine induction air was no longer taken in from the inboard leading edge openings). So, I imagine drag was probably consistant with the F4U-1D.
It may be interesting to note that the P-47B came in at .0213, even lower than the P-39N! Adding the under wing pylons and bubble canopy bumped drag up. Johnson's Jug had neither, so it should be somewhere between the P-47B (which lacked even the belly shackles) and the P-47D-25. Probably close to .0218 give or take a tiny bit. That will certainly aid in relation to maximum speed. Comparing flat plate area using a Cdo for the P-47D-5 of .0218, the F4U-1D calculates at 8.58 sq/ft, the P-47D-5-RE at 6.54 sq/ft. (Drag data from NACA L5A30 and ACTR 4677). Considering the size of the Thunderbolt, and the diameter of the engine, its Cdo is remarkably low.
For comparison's sake, the P-51D comes in at .0176, the P-63A at .0203 and the P-40E at .0242.
My regards,
Widewing
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Its a good thing Bob Johnson never saw hennings charts......He would have never got a kill in his inferior US aircraft :rofl
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WW,
The F4U-1D was faster than the P-47D even with less HP at sea level. Also check the document on my website for Cdo listings of many American Fighter types of 1944. The F4U-1D is .020 and the P-47D is .022. There is a detailed breakdown of the F4U-1D drag including rocket rails, bomb racks etc.
Having said that I don't see why 470MPH would not be attainable at 32,000FT if an F4U-3 could do 480MPH at 64" MAP at the same alt?
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Hi Widewing,
>When Johnson said during my interview [...]
I hadn't realized it had been you doing the interview :-) Great job!
>I thought a speed just above 450 mph was reasonable, and I still think that it is.
I think we're not far apart here as my estimate arrives at a similar speed, too. The problem I see is only altitude - if we agree that Johnson's engine couldn't pull 72" Hg at 32000 ft, this means that at whatever the critical altitude for 72" Hg might be, the P-47D would be even faster there. If we take the 470 mph at 32000 ft literally, we might have a 480+ mph top speed P-47D.
I'd agree that just above 450 mph would be a reasonable speed for a 72" Hg P-47D, but at a lower altitude than 32000 ft.
>And believe me, there was nothing that Johnson was going to encounter in December of 1943 that could get within 60 mph of his Jug at altitude anyway.
Just for the trivia value, the Me 109G-1/R2 (GM-1 equipped) did achieve 410 mph @ 39400 ft. I figure it might do around 420 mph @ 32000 ft, which would be about the same as a standard P-47D.
>When I examine the power curve for the P-47M-1-RE, I see that it could reach 475 mph at 32,600 feet, pulling 72" Hg.
This partly explains the P-47M analogy - the P-47M reaches its top speed due to the ability to sustain high boost pressure at very high altitude. At equal altitude below critical altitude, the P-47M speed gain was mainly due to the "cleaning up" done to the aerodynamics.
(For the F4U-3 comparison, the full 72" Hg seem to be available only up to around 28500 ft from the R-2800-C, by the way.)
>Now about comparing drag between the P-47D/N and F4U-3. In terms of drag coefficient, the P-47D-25 thru M is lower than the the F4U-1D.
The F4U-4 comparison reports lists the F4U-3 as capable of 486 mph @ 30000 ft on 2800 HP, while the standard P-47D achieves only 425 mph on 2200 HP. That would give the standard P-47D a top speed of 461 mph, indicating a higher total drag for the P-47 than for the F4U-3. (I'm not sure the data for the F4U-3 is real flight test data, though.)
The second reference P-47 might be closer, though at 32000 ft estimates are a bit difficult due to the increased compressiblity drag.
Regards,
Henning (HoHun)
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Hi Nomak,
>Its a good thing Bob Johnson never saw hennings charts......He would have never got a kill in his inferior US aircraft :rofl
Which charts? Where did I call the P-47 an "inferior US aircraft"?
If you want to see what the P-47 is really worth, just superimpose the speed and climb graphs of the standard P-47D I'm using for comparison, and those of the Fw 190A-8.
The P-47D is slightly faster below 20000 ft than the boosted Fw 190A-8 (with erhöhtem Ladedruck), and much faster above that altitude. While the Fw 190A-8 has a slight climb rate advantage at low altitude, both types are equal at around 25000 ft, and above that the P-47D gains an advantage.
At 27700 ft, the P-47D is almost 70 mph faster than the Fw 190A-8 - I'd certainly not call that "inferior" :-)
Even the Me 109K-4, though it would easily outclimb the P-47D at any altitude and outrun it just fine at low and medium altitude, couldn't compete with the P-47D's speed above 25000 ft.
As the strategic air war in the ETO raged between 20000 - 30000 ft, the P-47D was certainly better suited for it performance-wise than the Fw 190, and was good enough to take on even the highest-performance Me 109 ever built.
If I'd to pick a WW2 fighter that the P-47 is "inferior" to, I'd select the P-51, not a Luftwaffe fighter.
(I'll leave it as an excercise for the reader to figure out what I think the best WW2 piston fighter was.)
Regards,
Henning (HoHun)
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I would guess at a bearcat, but that depends on what you mean by "WWII AC".
My money would be on the P-47D as the allied fighter AC that that had the most impact on the air war over europe
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Originally posted by HoHun
Hi Widewing,
The F4U-4 comparison reports lists the F4U-3 as capable of 486 mph @ 30000 ft on 2800 HP, while the standard P-47D achieves only 425 mph on 2200 HP. That would give the standard P-47D a top speed of 461 mph, indicating a higher total drag for the P-47 than for the F4U-3. (I'm not sure the data for the F4U-3 is real flight test data, though.)
The second reference P-47 might be closer, though at 32000 ft estimates are a bit difficult due to the increased compressiblity drag.
Regards,
Henning (HoHun)
What hasn't been mentioned is that the F4U-3 was really the XF4U-3. Three prototypes were built and tested. Like all prototypes, these were carefully built aircraft. What I would like to see is flight data on this bird from the Navy, Vought was considered one of the worst when it came to padding performance. Grumman test pilot Corwin Meyer (Corky) thought so little of Vought's claims for the XF2G-1, that he challenged them to race it against the XF8F-1 Bearcat. Vought was reluctant, but finally agreed to the race. With both fighters doing run-ups on the end of the runway at NAS Pautuxtent River, Vought's Chief Engineer quietly asked the Navy to prevent the race, which they did by calling both back to the service ramp. Meyer was convinced that the 460 mph XF8F-1 would have won easily.. Why was the XF8F-1 so fast? Because, it was powered by an engine purposely built for maximum possible power. That's what prototypes were all about, and gundecking the specs to impress the Navy was SOP.
So, if we're going to compare prototypes, let us include the mighty XP-47J. It was powered by a P&W R-2800-57 "C" series engine with the latest and more efficient G.E. CH-5 turbo. The engine was rated for 2,800 hp at 32,600 ft @ 72" Hg. It was built from a modified P-47D-20 airframe. Changes were significant, as the fuselage was shortened by some 3 feet due to a revised engine installation.
Performance was staggering, to say the least. Maximum level speed was 507 mph @ 34,300 ft.
Climb was equally impressive, Climb from sea level was 4,930 fpm, and it was still climbing at 4,000 fpm as it passed 20,000 feet. Empty weight was just 9,663 pounds. Designed as an interceptor, the XP-47J was an awesome monster. However, it was a much massaged prototype, and such lofty performance could not be expected in production aircraft. As it was, the XP-47J program was cancelled in favor of the XP-72. Designed for altitudes between 20,000 and 30,000 ft., it made 490 mph @ 25,000 feet during preliminary testing with an engine still early in its development (R-4360).
Note: XP-47J performance numbers are from factory data sheets.
Of all the American fighters that reached production during WWII, none can come close to matching the P-47M for speed at high altitude. Not even the P-51H could come close to the big M above 27,000 feet.
My regards,
Widewing
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Hi Widewing,
>What I would like to see is flight data on this bird from the Navy, Vought was considered one of the worst when it came to padding performance.
Well, that would actually reinforce my point about the F4U-3 speed not being realistical for a front-line P-47D, wouldn't it? :-)
Regards,
Henning (HoHun)
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Widwing,
Some facts about the F4U-3 series.
The Navy accepted these aircraft from Goodyear not Vought so they actually had a FG-3 designation not XF4U-3. There were 26 aircraft delivered to the Navy at Johnsonville between July 3 and 7th 1945. They remained in service until 31 July 1949. Two of them were assigned to Patuxant for electronics testing. BuNos 92382 and 92383. Vought actually built the first two XF4U-3's in 1942.
Also the NAVAIR reports as well as the Royal Navy confirm all of the Vought claims for speed for the rest of the F4U series.
And Goodyear made the F2G too not Vought.
Remember these three items.
1. Only four aircraft types have ever won at the Reno unlimited air races. A F4U-1 with a R-4360 is one of them in 1985 setting the course record at the time.
2. The F2G's dominated when pitted against P-51's, P-63's, P-38 and P-39 running at 80" MAP with the best fuels the AAF could provide in the Cleveland air races and set speed records that lasted 30 years.
3. Corkey Meyer tested the F4U-4 and found it to be faster than listed speed at sea level. 380+MPH
WW,
Have you ever interviewed Boone Guyton when he was alive?
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I must admit that I am terrible impressed by everyone's maturity and reserve in discussing differing perpsectives on the "facts".
I have found this thread a wonderfull read and have enjoyed all the points presented.
Would that other threads maintain this high level of integrity and respect. to all.
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Aye, Drunky, havent seen any 'mother' insults or anythin here...(almost miss them;) Widewing, do you have a link to some of these articles? Sounds like good reading