XP72 "superthunderbolt" vs TA152 How would they stack up?
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wuzak
Captain
The F4U-4 was also mechanically supercharged - with the "sidewinder" -32W.
There was one F4U that was turbocharged (F4U-3?) but it did not go into production.
IIRC the F8F-2 was turbocharged, but that was well and truly a post war aircraft.
The R-2800-30W (from the F8F-2) was mechanically supercharged, hence my proposal to comapre it with F4U.
The attacher 'power chart' shows that power falls off right from 1000 ft, from 2200+ HP to some 1670 HP at 20000 ft and so on (all for military rating). IIRC the supercharger (internal or auxiliary?) was of variable type (akin to DB, or two-stage V-1710s).
The attacher 'power chart' shows that power falls off right from 1000 ft, from 2200+ HP to some 1670 HP at 20000 ft and so on (all for military rating). IIRC the supercharger (internal or auxiliary?) was of variable type (akin to DB, or two-stage V-1710s).
The Pilot's Flight Manual for the F8F can be found here, Grumman F8F-2 Bearcat Fighter Aircraft Pilot's Flight Manual - United States Navy - Google Books
Wuzak, never heard of a turbocharger on the 'Bear.
Wuzak, never heard of a turbocharger on the 'Bear.
wuzak
Captain
Sorry, my mistake.
GregP
Major
Here is the URL of WWIIaircraft performance.org: FW 190 D-9 Flight Trials
According to test reports of an Fw 190D-9:
With special emergency power, MW50, 3250 RPM, gaps and engine sealed: Max speed was 412 mph @ 20,000 feet and performance fell off after that. Started out at about 378 mph @ sea level, went to 402 mph @ 6,000 feet, fell off to 392 mph @ 11,700 feet.
When prepared normally, without gap seals, using takeoff and emergency power: Max speed was 342 mph @ sea level, 383 mph @ 10000 feet, falling to 378 mph @ 12000 feet, 413 mph @ 20000 feet, falling to 392 mph @ 26000 feet.
The performance clearly falls off at 20,000 feet from the graphs.
You can easily find the P-51B test on the same site. It shows:
Test of a P-541B with V-1650-7 engine @ 8500 pounds:
392 mph @ sea level, 428 mph @ 9800 feet, falling to 420 mph @ 17400 feet, increasing to 454 mph @ 25600 feet, falling to 441 mph @ 35000 feet.
These aren't MY tests, they were run in the 1944 - 1945 timefame by service pilots and are simply reports of results. So, I make no claims about the test conditions, though the conditions are stated in most cases. The Fw 190D-9's tested had a bad reliability record in test, most damging their superchargers during high-speed testing.
From only these two reports, one would not choose an Fw 190D-9. Of course, these are absolute maximum speeds and are only useful to factory test pilots. Real combat pilots hardly ever see these speeds unless they are in a a steep dive. Combat speed for most WWII fighters, regardless of maximum speed capability, was in the 300 mph to 360 mph range ... and almost all front-line fighters could DO these speeds. The important thing was to see the other guy first and get into a favorable position from which to attack. Most combat kills were pilots who never saw their attacker. The classic "dogfight" was VERY rare.
I also have several books (currently in storage) dedicated to the FW 190 series, and they don't make outlandish claims for the Fw 190D-9, either. From the books, it looks like a good, solid airplane, but not "the best" of WWII.
Sorry about the GM-1, I was thinking of MW50 (water methanol injection).
According to test reports of an Fw 190D-9:
With special emergency power, MW50, 3250 RPM, gaps and engine sealed: Max speed was 412 mph @ 20,000 feet and performance fell off after that. Started out at about 378 mph @ sea level, went to 402 mph @ 6,000 feet, fell off to 392 mph @ 11,700 feet.
When prepared normally, without gap seals, using takeoff and emergency power: Max speed was 342 mph @ sea level, 383 mph @ 10000 feet, falling to 378 mph @ 12000 feet, 413 mph @ 20000 feet, falling to 392 mph @ 26000 feet.
The performance clearly falls off at 20,000 feet from the graphs.
You can easily find the P-51B test on the same site. It shows:
Test of a P-541B with V-1650-7 engine @ 8500 pounds:
392 mph @ sea level, 428 mph @ 9800 feet, falling to 420 mph @ 17400 feet, increasing to 454 mph @ 25600 feet, falling to 441 mph @ 35000 feet.
These aren't MY tests, they were run in the 1944 - 1945 timefame by service pilots and are simply reports of results. So, I make no claims about the test conditions, though the conditions are stated in most cases. The Fw 190D-9's tested had a bad reliability record in test, most damging their superchargers during high-speed testing.
From only these two reports, one would not choose an Fw 190D-9. Of course, these are absolute maximum speeds and are only useful to factory test pilots. Real combat pilots hardly ever see these speeds unless they are in a a steep dive. Combat speed for most WWII fighters, regardless of maximum speed capability, was in the 300 mph to 360 mph range ... and almost all front-line fighters could DO these speeds. The important thing was to see the other guy first and get into a favorable position from which to attack. Most combat kills were pilots who never saw their attacker. The classic "dogfight" was VERY rare.
I also have several books (currently in storage) dedicated to the FW 190 series, and they don't make outlandish claims for the Fw 190D-9, either. From the books, it looks like a good, solid airplane, but not "the best" of WWII.
Sorry about the GM-1, I was thinking of MW50 (water methanol injection).
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According to some quite knowledgeable (ex-)members of this forum this site you mentioned seems to be very biased and selective regarding the performance figures of german aircraft in favor of allied aircraft.
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GregP
Major
The site isn't one with members. It is a collection of reports published in the WWII timeframe. The people collecting the reports have no interest in changing the reports, they simply collect and post them.
I can think of another site clearly biased toward German aircraft, and I don't use it because I have confirmed the webmaster takes the maximum numbers from large numbers of reports and collects them as the typical perfromance. I believe the real way to be unbiased is to take the reports, read them all, and then assume the truth lies in between the best and worst of the numbers.
But, that's just my take on it.
Last, I don't say that site is authoritative. I said it shows reports compiled by combat pilots in the WWII timeframe. They clearly show the Fw 190D-9 as a good fighter, but not the best. There well may be other site claiming the Fw's as the best, but bias works both ways.
I can think of another site clearly biased toward German aircraft, and I don't use it because I have confirmed the webmaster takes the maximum numbers from large numbers of reports and collects them as the typical perfromance. I believe the real way to be unbiased is to take the reports, read them all, and then assume the truth lies in between the best and worst of the numbers.
But, that's just my take on it.
Last, I don't say that site is authoritative. I said it shows reports compiled by combat pilots in the WWII timeframe. They clearly show the Fw 190D-9 as a good fighter, but not the best. There well may be other site claiming the Fw's as the best, but bias works both ways.
... and the site you posted is on the other side of the spectrum. I have far too few original documents myself to make a thorough assessment, but when I see readily available test reports "left out" and quotes taken out of context or selected very one-sidedly (others simply ignored), I know what to take with a grain of salt.
What would those readily available test reports be?
davparlr
Senior Master Sergeant
Could you provide the specific site. I could not find any reference showing these values for SL and max. They are in conflict with several other test. 8500 lbs is light for a P-51B.
GregP
Major
Sure. http://www.wwiiaircraftperformance.org/mustang/p-51b-engdiv-na-flighttestdata.jpg
This graph shows the P-51B going a bit faster at 27,400 feet than I have ever seen anywhere else.
That's why I usually take all the numbers and average them for a first-order estimate.
I see reports on the Fw 190D's and Ta-152's that vary as much as 60 mph or more. What that tells me is there is a wide variety of test conditions, pilots, and test configurations. Might also be some bias there somewhere.
I get most of my estimates these days from the Planes of Fame library in Chino, and they have a LOT of volumes.
This graph shows the P-51B going a bit faster at 27,400 feet than I have ever seen anywhere else.
That's why I usually take all the numbers and average them for a first-order estimate.
I see reports on the Fw 190D's and Ta-152's that vary as much as 60 mph or more. What that tells me is there is a wide variety of test conditions, pilots, and test configurations. Might also be some bias there somewhere.
I get most of my estimates these days from the Planes of Fame library in Chino, and they have a LOT of volumes.
davparlr
Senior Master Sergeant
I believe this is a North American engineering estimate which is probably based on perfect performance parameters. It does not have a date, tail number, configuration parameters, or identified test points. I usually log this in as interesting but usually not realistic performance in application.
GregP
Major
Yeah, I agree. Most of the performance charts I see for the P-51D list the max speed as 437 mph at best altitude, with the B model going 441 mph at best altitude. Those numbers are from reports from the US Military, with aircraft ID, tail numbers, dates, times, and test conditions, too. Today, a P-51D cruises about 235 knots (270 mph) in the U.S.A. due to the speed limit below 10,000 feet in US airspace of 250 knots.
As I said earlier, absolute maximum speed is for factory test pilots. The Combat speed of the P-51D was in the 300 - 360 mph range, with typical cruise at 250 -280 mph, which is very similar to most good WWII fighters. They see faster in a dive from altitude, but that didn't happen often as it tended to separate you from your unit quickly and make you an obvious single straggler unless your wingman came with you.
As I said earlier, absolute maximum speed is for factory test pilots. The Combat speed of the P-51D was in the 300 - 360 mph range, with typical cruise at 250 -280 mph, which is very similar to most good WWII fighters. They see faster in a dive from altitude, but that didn't happen often as it tended to separate you from your unit quickly and make you an obvious single straggler unless your wingman came with you.
Shortround6
Major General
Max level speed is just what it says. The maximum speed the plane could achieve while flying straight and level at that altitude.
"Combat speed" is going to lower but there is no real way to measure "combat speed". Any deviation from straight and level flight is going to slow the plane down, even a bank of 5-10 degrees is going to try to cause a gentile turn, the combination of the loss of lift and the drag will slow the plane down. AND that is assuming the plane was at max speed to begin with. It also takes time to accelerate to max speed and just like a car, the last few mph take a disproportionate amount of time to get. A 450mph plane doing 300 mph will take more seconds to accelerate from 350mph to 400 mph than it did from 300mph to 350 mph and the last 50 mph, from 400 to 450 will take an even longer time period.
A 440mph plane will, on average, have a higher combat speed than a 400mph plane because at the lower speeds (320-360mph) the 440mph plane will have better acceleration coming out of a gentile maneuver or cruise setting.
"Combat speed" is going to lower but there is no real way to measure "combat speed". Any deviation from straight and level flight is going to slow the plane down, even a bank of 5-10 degrees is going to try to cause a gentile turn, the combination of the loss of lift and the drag will slow the plane down. AND that is assuming the plane was at max speed to begin with. It also takes time to accelerate to max speed and just like a car, the last few mph take a disproportionate amount of time to get. A 450mph plane doing 300 mph will take more seconds to accelerate from 350mph to 400 mph than it did from 300mph to 350 mph and the last 50 mph, from 400 to 450 will take an even longer time period.
A 440mph plane will, on average, have a higher combat speed than a 400mph plane because at the lower speeds (320-360mph) the 440mph plane will have better acceleration coming out of a gentile maneuver or cruise setting.
Mr Shortround 6
I believe your last statement is usually but not always true. A fighter with top max speed because of exceptional aerodynamics may have poorer accelaration in middle speeds in comparison with a fighter with better power loading but lower max speed because of worse drug characteristics. As the speeds increase , and drug becomes more important than power loading and aproaching the top spectrum of speeds the cleaner airframe is fastest.
Also some aircrafts may be fast on level flight but loosing more speed during manouvers than other aircraft.
If i am wrong please correct
Shortround6
Major General
You are not wrong which is why I wrote "on average" 
A P-51 Allison Mustang being an example of a fast airplane with poor acceleration. At least at the higher altitudes it was capable of. Depending on engines fitted a Merlin Mustang could have double the power available at 25-26,000ft than an Allison powered one which is not reflected in their max level speeds but that tends toward being one of the more extreme samples.
A P-51 Allison Mustang being an example of a fast airplane with poor acceleration. At least at the higher altitudes it was capable of. Depending on engines fitted a Merlin Mustang could have double the power available at 25-26,000ft than an Allison powered one which is not reflected in their max level speeds but that tends toward being one of the more extreme samples.
GregP
Major
Shortround, there is an EASY way to measure combat speed ... read combat reports. The speeds (in IAS) are reported.
I won't get into a research project for someone else at this time (I have one myself that has been running for more than 15 years), but there are plenty of combat reports available to the person who looks for them. Reading about 10 - 15 combat reports for any single type will give the reader a good feel for the combat speed of a particular mount.
I won't get into a research project for someone else at this time (I have one myself that has been running for more than 15 years), but there are plenty of combat reports available to the person who looks for them. Reading about 10 - 15 combat reports for any single type will give the reader a good feel for the combat speed of a particular mount.
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GregP
Major
Siegfried, I don't belive the Jumo 213 achieved 1900 HP; it achieved 1900 PS (or cv, whichever you like), which is 1874 horsepower (550 ft-lbs. sec type HP).
The site may SAY 437 mph, but the chart quoted above SHOWS 450 mph.
I never said that no Fw 190D or Ta 152 was fitted with MW50, I said the early ones were not. Considering that only about 43 Ta-152's were ever delivered .... how many were early?
As for the Fw 190D, I have never seen a calculation of "early" or "late" models. They built about 1,805 D-9's but have no number delivered and no number of "early" or "late"; built 17 Fw 190D-11's with no known number delivered (guess that qualifies as "a few"); built 3 Fw 190D-12's; and built 17 Fw 190D-13's with 2 known delivered. There is ample evidence that many D-9's were "early," but no definitive definition of what "early" means.
So guys, unless you know the numbers (and I doubt they exist), then we collectively don't know how many were delivered with early or late engines. If someone DOES know, then the proof will have to be GOOD, considering the records were lost. We can say some were early and some were late.
None of the D-9's had the top speed of the P-51D, though the difference was minor, and top speed was not really useful in combat unless you were running. If a Focke-Wuld Fw-190D was running from a P-51, he would likely not gain or be caught, assuming the P-51 pilot or pilots had the fuel and desire to chase and kill. In general, the Fw 190D seies was a very good fighter and was not an opponent to be taken lightly by ANY Allied figher, so if one were to run, he was likely allowed to do so by Allied fighters in the area unless he was damaged. I'd say the P-51 would be accorded the same respect by the Luftwaffe, considering how many P-51's were likely to be around as friends and lack of ability to catch the P-51 without a height advantage to trade for speed.
The site may SAY 437 mph, but the chart quoted above SHOWS 450 mph.
I never said that no Fw 190D or Ta 152 was fitted with MW50, I said the early ones were not. Considering that only about 43 Ta-152's were ever delivered .... how many were early?
As for the Fw 190D, I have never seen a calculation of "early" or "late" models. They built about 1,805 D-9's but have no number delivered and no number of "early" or "late"; built 17 Fw 190D-11's with no known number delivered (guess that qualifies as "a few"); built 3 Fw 190D-12's; and built 17 Fw 190D-13's with 2 known delivered. There is ample evidence that many D-9's were "early," but no definitive definition of what "early" means.
So guys, unless you know the numbers (and I doubt they exist), then we collectively don't know how many were delivered with early or late engines. If someone DOES know, then the proof will have to be GOOD, considering the records were lost. We can say some were early and some were late.
None of the D-9's had the top speed of the P-51D, though the difference was minor, and top speed was not really useful in combat unless you were running. If a Focke-Wuld Fw-190D was running from a P-51, he would likely not gain or be caught, assuming the P-51 pilot or pilots had the fuel and desire to chase and kill. In general, the Fw 190D seies was a very good fighter and was not an opponent to be taken lightly by ANY Allied figher, so if one were to run, he was likely allowed to do so by Allied fighters in the area unless he was damaged. I'd say the P-51 would be accorded the same respect by the Luftwaffe, considering how many P-51's were likely to be around as friends and lack of ability to catch the P-51 without a height advantage to trade for speed.
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