Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: F4UDOA on February 06, 2006, 10:03:45 AM
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Many people may have read about the report where the Army Tested the F4U-1 against the P-38, P-51 and P-47. Well I have heard it reffered to many times but I have never seen it until now.
Mike Williams and Neil Stirling of Spitfire Testing fame came across the report and shared it with me. It is copyright and I am posting it with their blessing so please be diligent in it's use and reposting. It should also be noted that many others on these boards with similar access to critical information are not as forthcoming with sharing and actually insist on being reumbersed. I think history is public domain and should be shared so kudos to Mike and Neil for doing the work for the rest of us.
A couple of comments to note when reading this report. I have some corresponding AAF documents that show the actual testing began in February of 1943 and the F4U in question is an early production F4U-1 without the Link Tab ailerons.
The Aircraft it is being testing against are
P-51A/F-6 according to the serial number noted in the flight card. Not sure if it is an F-6 but the serial number batch is linked to some F-6 types. It is certainly an Allison engine in either case.
The P-38G in the test is noted as being "stripped" or "light weight". I do not know why they tested this way and I do not have the flight card.
The P-47C I assume is standard production but I do not have the flight card or weights.
http://mywebpages.comcast.net/markw4/AAFF4U.pdf
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and THANKS to all those who contribeuted to being able to post this!
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Thank you very much to all for making this availiable !
38
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Please someone say something about something else of other than the stinking Luftwaffe:rolleyes:
Anything, just don't talk about boost levels in the Uber this or the Galland that.
It is like watching I love Lucy re-runs over and over and over. Pretty soon the forums will be all Crummp all the time. He must be indepentantly wealthy to post as much as he does.
Anyway doesn't anyone want to comment on this report? Does anyone remember the USN or the PAC theater??
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Army air force pilot testing a navy ride . No wonder there was so much complaining in the test data.
:D
Bronk
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Army air force pilot testing a navy ride . No wonder there was so much complaining in the test data.
There was a lot of whining in that report huh. But at the end they had to report that the F4U was a better dogfighter. It must have been painful.
BTW they also did their testing at 49'MAP instead of 54" MAP the F4U could pull. Cheaters!!
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Originally posted by F4UDOA
There was a lot of whining in that report huh. But at the end they had to report that the F4U was a better dogfighter. It must have been painful.
BTW they also did their testing at 49'MAP instead of 54" MAP the F4U could pull. Cheaters!!
I'll bet he was instructed NOT to go to 54 MAP. We cant have USAAF aircraft outdone.
Inter service rivalry runs deep.
Do you have any comparisons done with the 51b .
Bronk
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Lol, so a bit skewed results then, eh? Funny that even a slightly underpowered Corsair is considered a superior dogfighter than the top three USAAF birds. :D
Y'know this is the only thing I've ever read that complained about sluggishness of roll in the F4U, or of the controls in general at high airspeeds. Most everything I've ever seen said the Corsair handles like a dream as the airspeed piles on (certainly better than the compression-prone 38 and 47).
I'd heard about problems with the early Corsair's cowl flaps, to the point where many pilots had them permanently fixed closed (also with problems of fuel leaking from the main tank, forcing the panels to be taped down: The source of the light-colored design on the nose areas of many Corsairs just forward of the cockpit).
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Heya Saxman,
The early production F4U-1's did not have the Spring Tab ailerons. They were added after a few months but this bird was actually delivered to the Army in February 1943 so it was not equiped. The elavators were also reinforced. The F4U-5 had Spring tab rudder and elevators.
Not bad though out turning a stripped P-38G. Even the British evaluation list the small turning circle as on of it's best features. So much for not being able to turn myth.
I would like to know what MAP they were running the P-51A at. At 46" it climbed like a dog but that Allison could run up to 60" plus at low alt.
Bronk,
The F4U-1A test against the P-51B has been out for a while.
Check my site
http://mywebpages.comcast.net/markw4/
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lots of good reading there thanx.
Bronk
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Love the site, FD. I thought the article comparing the B-Pony was interesting. That test would hold up fairly well for the 51D, too, wouldn't? I can't recall there being a whole lot of differences in performance (actually, some books I've read make the D out to be a few MPH SLOWER because of the raised canopy) between the B/D other than improved firepower, and this article would seem to confirm that even the refined "early" Hogs were superior to the Mustang (and that the AH Pony may be a bit overpowered..
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I think you have to keep in mind that interservice rivalry went both ways. Note that the F4U-1 in the P-51B test is running a higher power setting, increased water injection flow rate, a different prop, and was drag prepped. The production F4U-1A, was slower through most of the altitude band. Also in the test they list both F4Us as having a 750-1000fpm climb rate advantage! That really makes me wonder what power setting they were using on the P-51 - check out the chart on page 5 of this (http://mywebpages.comcast.net/markw4/MSWF4UDATA.pdf) document.
With regard to the difference between the P-51B and D, the main one was the engine. Many P-51Bs had a V-1650-3 that was more geared to high altitude performance, while the later B and the D models had a V-1650-7 that was geared for better lower alt performance. Generally the -7 planes were faster from about 0-12k and from 20-26k, with the -3 planes being faster in the other ranges. Mike and Neil's page here (http://www.spitfireperformance.com/mustang/mustangtest.html) has a lot of P-51 testing from a variety of sources. AH's P-51D almost exactly matches the North American tests, which fall about in the middle of the range.
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I suspect the climb trials were done at Military Power. In this case, the F4U-1 would out-climb the P-51B pretty much as stated in the USN comparison.
(http://i22.photobucket.com/albums/b311/qwejibo/P51_F4U_MIL_Climb.gif)
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Military power on the P-51B/D was 3000rpm, 61" HG. The 2700rpm/46" is a reduced power setting, so that explains the poor performance. It would be the equivalent of using a 2550rpm/45" setting on the F4U.
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"Please someone say something about something else of other than the stinking Luftwaffe"
HAH!! Youz cannot fight ze might of Luftwoffel wit U'r puny Mk1 Corzair!
Be gone wit zat unterperfoming pile of zunk!
:D :D :D
-C+
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Originally posted by Sable
Military power on the P-51B/D was 3000rpm, 61" HG. The 2700rpm/46" is a reduced power setting, so that explains the poor performance. It would be the equivalent of using a 2550rpm/45" setting on the F4U.
Interesting. I used UK/RAF data(since I haven't found any US data at anything except WEP performance), which list the power ratings as:
Max. climb & level continuous: 2700rpm & 46"map
Combat 5 mins. limit: 3000rpm & 67"map*
* 61"map may be used for 15 minutes
At 2550rpm & 45"map the F4U-1 would outclimb the P-51B by 250fpm below 7500ft, equal climbrate up to 23000ft, above that the F4U-1 lower by up to 500fpm.
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Mike and Neil have a couple of US tests of V-1650-3 equipped P-51B's here (http://www.spitfireperformance.com/mustang/p51b-12093.html) and here (http://www.spitfireperformance.com/mustang/p-51b-6883.html). Unfortunately the first one, while being at the 61" power setting, is tested at 8400lbs, and the second is at the 67" (WEP) power setting. Page 8 of this (http://mywebpages.comcast.net/markw4/MSWF4UDATA.pdf) document has a chart with a comparison of the F4U-1 and P-51B (as well as the P38 and F4U-4) at their WEP powers. It seems like they would be pretty close at their normal weights and military power.
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Justin,
The Pony in the AAF test is a P-51A/F-6. So the Mil power rating would have been approx 46" MAP. However I have seen that engine run up to 60" MAP in some test. That is why I wonder what MAP it was tested at considering it outclimbed the Hog up to 10K. At 46" there is no way that it could have unless the F4U was running at less than 50".
The Navy test is the P-51B however I have never seen the climb chart for that one. Also the F4U-1's used in thse test both had ADI and a paddle prop. Different ballgame.
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Originally posted by Sable
I think you have to keep in mind that interservice rivalry went both ways. Note that the F4U-1 in the P-51B test is running a higher power setting, increased water injection flow rate, a different prop, and was drag prepped. The production F4U-1A, was slower through most of the altitude band. Also in the test they list both F4Us as having a 750-1000fpm climb rate advantage! That really makes me wonder what power setting they were using on the P-51 - check out the chart on page 5 of this (http://mywebpages.comcast.net/markw4/MSWF4UDATA.pdf) document.
I thought about commenting on this last evening, but was simply too tired to bother.
Anyone accepting that Navy test on face value should report to Brooklyn and sign the contract for their bridge. The Navy did just about everything they could to maximize the F4U-1 and minimize the Mustang. This test is useless for anything beyond its amusement value.
When comparing unsullied test data for the P-51B and the F4U-1, you see that the Mustang wins easily in terms of performance. Due to supercharger gearing, the P-51B loses speed gradually until the F4U-1 is close at 20,000 feet. But, go a bit higher and the P-51B's blower shifts and the Mustang disappears like a fart in a tornado.
In terms of climb, the P-51B outclimbs the F4U-1 with ease over 95% of the curves.
All of that said, the F4U-4 more than equalizes the equation.
An added thought: It has always seemed to me that North American and Republic were much faster at incorporating major improvements into production aircraft than Lockheed or Vought. In Vought's defense, the ultra-conservative approach of the Navy to introducing upgraded aircraft may be the cause. There's little doubt that Grumman's F7F and F8F could have been in service many months sooner, but it seems that the Navy was far more accepting of the status quo than the AAF.
My regards,
Widewing
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Originally posted by Widewing
An added thought: It has always seemed to me that North American and Republic were much faster at incorporating major improvements into production aircraft than Lockheed or Vought. In Vought's defense, the ultra-conservative approach of the Navy to introducing upgraded aircraft may be the cause. There's little doubt that Grumman's F7F and F8F could have been in service many months sooner, but it seems that the Navy was far more accepting of the status quo than the AAF.
My regards,
Widewing
Just a thought . Might it because they had to land on a boat and not a runway. Id be a little conservative also.
Bronk
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And yet, this same "progress-minded" AAF decided the status quo did the job just fine and there was no need to push the development of the P-80, which could ALSO have seen deployment during WWII.
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Originally posted by Saxman
And yet, this same "progress-minded" AAF decided the status quo did the job just fine and there was no need to push the development of the P-80, which could ALSO have seen deployment during WWII.
If you research the P-80 you'll see that the aircraft evolved as fast as the technology would allow. The first prototype didn't fly until January of 1944. Even that was delayed due to having to wait for a British engine to be delivered.
The P-80 wasn't adequately debugged until well into 1946. There was zero chance that the P-80 could have seen truly combat ready before 1946. Had the program been started in 1941, then maybe. But the contract wasn't signed until the fall of 1943.
My regards,
Widewing
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Originally posted by F4UDOA
Justin,
The Pony in the AAF test is a P-51A/F-6. So the Mil power rating would have been approx 46" MAP. However I have seen that engine run up to 60" MAP in some test. That is why I wonder what MAP it was tested at considering it outclimbed the Hog up to 10K. At 46" there is no way that it could have unless the F4U was running at less than 50".
The Navy test is the P-51B however I have never seen the climb chart for that one. Also the F4U-1's used in thse test both had ADI and a paddle prop. Different ballgame.
Well, I was only considering the USN comparo - as you can see, I used the Mil power climb chart you posted of one of the F4U-1's used in that trial. The Mustang is from RAF data.
For the AAF trial: The card on the last page claims the F4U-1 climb power was 2700rpm & 50"map(afaik not a standard rating) but with rather high "indicated" climbrates of 2800fpm@5k, 2350fpm@15k & 1950fpm@25k?!.
The BuAer docs for F4U-1 at 2700rpm & 53"map(mil pwr) indicate climbrates of 2200fpm/2050fpm/1250fpm for those altitudes.
AAF docs here (http://www.spitfireperformance.com/mustang/p-51-37320.pdf) indicate that the P-51 at 3000rpm & 46"map would be superior to the BuAer F4U-1(mil pwr) below 12-15,000ft.
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The BuAer docs for F4U-1 at 2700rpm & 53"map(mil pwr) indicate climbrates of 2200fpm/2050fpm/1250fpm for those altitudes.
Justin,
Do you have the F4U-1 BuAer charts? I have the Vought charts and the British test but not the BuAer. The numbers you spec are more in line with the Normal power than Mil power (50"+).
Your right the top speed MAP says 53.5" and climb power is 50" but those test were done in February 1943. The test against the Pony were done in May 1943 and at that time the highest MAP reached was 49". I getthe feeling that the Hog was sitting on the ramp somewhere breaking slowly for a few months before they drug it out for testing.
BTW, I know that testwas in Feb because of an British AIR-1777 doc I have that list the AAF results (speed/MAP/HP) and it is dated in February so the test could have even been earlier.
WideWing,
The AAF did the test I posted and besides complaining about the F4U they could not seem to defeat it in close in dogfighting. Why do you think they used a stripped P-38G for testing instead of a combat aircraft?
BTW the results of the test compare very similarly to the Robert Johnson artical you posted a while back.
The performance of the P-51B and F4U-1A with 2250HP are not that far when 100 octane fuel is used below 25K. The -1A will hold some advantage even in climb as shown by the performance curves. The trick is not to get carried away with the F4U-1 that was configured as a test bed for the F4U-4. The F4U-1A in that test was running at 60" MAP and 2250HP same as production A/C of the time.
(http://www.geocities.com/slakergmb/23d60700.jpg)
(http://www.geocities.com/slakergmb/23760700.jpg)
(http://mywebpages.comcast.net/markw4/air1777climb.jpg)
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Curve 2 is military power, 2000hp @ s/l & 12,039lbs. From this website (http://www.geocities.com/slakergmb/id67.htm)
(http://i22.photobucket.com/albums/b311/qwejibo/f4u-13.jpg)
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Btw, just for laughs - who would like a 377mph Mustang I in mid '43?
(http://www.ww2incolor.com/gallery/albums/British/p_51a_raf.sized.jpg)
377MPH AT SEA LEVEL THAT IS! :D
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The "What we've got is good enough" delays in the USAAF and US military in general went back well before 1943. The US began experimenting with jet propulsion BEFORE the bombing of Pearl Harbor (I think it was roughly around the same time the Brits and Germans). IIRC, the Bell Airacomet first flew under jet power c.1940/41 (not entirely sure of the date there). Not particularly impressive performance, (I think the P-51 and late-model Hogs were faster) but it WAS flying. It's just that after entering the war the US focused its attention on churning out existing designs, rather than moving development on a lot of more advanced projects, focusing on winning the war with what was proven, rather than experimental uberfighters (in part why nothing was made of monsters like the Chain Lightning).
Anyway, my main point was that the USN wasn't the only branch of service guilty of not putting time into R&D (point of order: Wasn't the F6F the ONLY American fighter to begin development AFTER the US entered the war?)
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Originally posted by Saxman
The "What we've got is good enough" delays in the USAAF and US military in general went back well before 1943. The US began experimenting with jet propulsion BEFORE the bombing of Pearl Harbor (I think it was roughly around the same time the Brits and Germans). IIRC, the Bell Airacomet first flew under jet power c.1940/41 (not entirely sure of the date there). Not particularly impressive performance, (I think the P-51 and late-model Hogs were faster) but it WAS flying. It's just that after entering the war the US focused its attention on churning out existing designs, rather than moving development on a lot of more advanced projects, focusing on winning the war with what was proven, rather than experimental uberfighters (in part why nothing was made of monsters like the Chain Lightning).
Anyway, my main point was that the USN wasn't the only branch of service guilty of not putting time into R&D (point of order: Wasn't the F6F the ONLY American fighter to begin development AFTER the US entered the war?)
Bell's XP-59A didn't fly until October 2, 1942, about 15 months before the XP-80 flew. Their YP-59A didn't flying until August of 1943, less than six months before the XP-80 flew. Moreover, it was realized that the YP-59 would never evolve into a viable fighter and were designated as advanced trainers as were the 100 P-59As built and delivered during 1944.
Work began on the XF6F-1 prior to the Pearl Harbor attack, with an order for the prototype being issued on June 30, 1941. I think that the only US fighter that comes close to being designed, developed, built and flown in combat during the US portion of the war was the P-63, which evolved out of the P-39E contract (placed on June 27 of '41) which ended up being cancelled in favor of Bell's XP-63 proposal.
My regards,
Widewing
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Justin,
Yeah, I meant the pre-ADI models.I would like to find the BuAer July 1943 document. I have the Vought and British test that are closer to the AAF test
The F4U-1A in that test is slightly heavier and hense the climb is not good at all. It is faster than the older -1's tested I assume because of the drag condition.
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Originally posted by justin_g
Btw, just for laughs - who would like a 377mph Mustang I in mid '43?
(http://www.ww2incolor.com/gallery/albums/British/p_51a_raf.sized.jpg)
377MPH AT SEA LEVEL THAT IS! :D
or a Mustang III aka P51B (british modified) used to chase V1s, would do
450mph @ 5k :) imagine the La7 pilot whines of being run down lol.
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Whels!?!?!?!
Dude, where ya been at?
I think the Allison Pony would be a great addition to AH. I don't know why when they tested it at 59" MAP they refused to climb it at more than 36" MAP. I assume they had an overheat problem.
It is easy to see why the Mustang was recognized as having so much potential so early on based on the test performed by the Brits with the Allison Ponies.
It is interesting that the Brit and Americans once recognizing this airframe potential did not just put a high HP engine in it and call it a day. They found ways to get as much fuel into it as possible and use it as a strategic fighter rather than a tactical figher. It would have been easy to simply put a two stage mechanical supercharger in it and have a very fast low alt fighter with very good ailerons and good wing loading. But instead the effort was made to design a long range fighter escort. Despite the loss at the BoB the Germans never developed this capability.
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I think that by the time the Alison-powered mustangs came out, the people involved realized the BOB was over, and that the new threat would be on continental Europe, and that meant more gas. They took the airframe and modified it in a big way (engine gearing, fuel, weapons, main purpose -- from ground attack with dive brakes to fighter/escort). They just knew that they didn't really need the A-36 Apache any more, but they DID need "Plane X" -- so they turned one into the other :P
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1. Mustang wing fuel tanks never changed size - 180gal total, for all models, from the prototype on(which was built before BoB was finished). The 85gal rear fuselage tank was introduced during P-51B production. The Mustang I was already acknowledged by the RAF as a long-range fighter - it was the first UK based single-engine fighter to cross the German border, in October '42.
2. Mustang I was in combat with the RAF for several months before the first A-36 even left the factory - in fact, the "Apache" was a modification of the original fighter into a dive-bomber/ground attack version.
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I went offline and tested the P-51B and F4U-1 for climb rate from sea level up to 25,000 feet. I used auto-climb. Both aircraft were clean, normal load with the exception that the F4U-1 carried 100% internal fuel and the P-51B carried 75% internal fuel. I didn't want to penalize the longer range Mustang, so I took only enough gasoline to allow it about a 25 mile greater range (as in the MA with its 2.0 fuel burn rate) than the F4U-1.
Rather than plot this to a computer generated graph, I plotted them on good old-fashioned ghost-grid vellum, the only graph vellum I have at home. Therefore, the grid does not show on a photocopy or when scanned.
I have included climb graphs borrowed from Mike Williams (scaled down to fit the BBS page rather than just link to the over-size image) for the P-51B and another BuAir graph for the F4U-1 for comparison.
You can see how using auto climb differs from the charted climb rates.
This is basically an FYI post, but I find it interesting to compare actual test data to what we observe in the game. I use auto-climb because it levels the playing field and takes the pilot out of the equation.
(http://home.att.net/~c.c.jordan/AH2-P51B-F4U1.jpg)
(http://home.att.net/~c.c.jordan/p51b-climb.jpg)
(http://home.att.net/~c.c.jordan/F4U-1.jpg)
My regards,
Widewing
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Hi Widewing,
>Rather than plot this to a computer generated graph, I plotted them on good old-fashioned ghost-grid vellum, the only graph vellum I have at home.
Hm, what's "ghost-grid vellum"? I'm only familiar with standard graph paper (called "millimeter paper" over here for obvious reasons :-), but that's usually an orange-red grid that survives copying.
>You can see how using auto climb differs from the charted climb rates.
I'm not sure comparing real-life tests to in-game tests will reliably show the effect of different methods, but it seems the climb rate in the auto-climb tests don't drop off as quickly as in the real-life tests. That would be just what you'd expect from an constant IAS auto-climb setting that is optimized for time to altitude, so your results look good in my opinion.
Regards,
Henning (HoHun)
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Originally posted by HoHun
Hi Widewing,
Hm, what's "ghost-grid vellum"? I'm only familiar with standard graph paper (called "millimeter paper" over here for obvious reasons :-), but that's usually an orange-red grid that survives copying.
Ghost-grid vellum is a very pale green and the grid is bearly visible. When you photocopy the page, the grid disappears. In the years before modern CAD systems, this type of vellum allowed you to sketch to scale and the finished sketch looked like an engineering drawing as the grid wasn't visible when copied. It was a way to sketch without using a T-square.
My regards,
Widewing
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Hi Widewing,
>In the years before modern CAD systems, this type of vellum allowed you to sketch to scale and the finished sketch looked like an engineering drawing as the grid wasn't visible when copied.
Ah, thanks, I imagine this was very useful indeed! It seems producing proper engineering drawings was a job nobody enjoyed back then. No "undo", just razor blades :-)
Regards,
Henning (HoHun)
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Widewing,
I understand your point but your fuel loads are a bit off IMHO. The F4U-1 carried 361 gallons of fuel with a range of 1500 miles. It had a longer range than the P-51B on internal fuel and would never practically carry that load into combat.
Also according to the Navy's F-1 range formula the P-51B had approximately the same range as a F4U-1D (550 to 500miles) with only 237 gallons of fuel. When the F4U-1A vs P=51B test was flown they adjusted the weight by reducing the P-51B takeoff weight to 9100lbs to make the ranges equal.
Also the test was flown with the late model F4U-1A at combat power 2250HP. This was essentially our F4U-1D except without external stores pylons.
So to redefine the the test you should reduce the P-51B weight by approx 323LBS and use the F4U-1D at combat power. Also the Hog is carrying 705lbs (2350rounds) of 50cal as compared to 394lbs (1260rounds) of .50cal which was pointed out by the Navy in the test report.
The reduced weight P-51B is noted as "Loading condition #2". The climb chart I posted above is from the exact F4U-1A flown by the Navy in that test.
(http://web.infoave.net/~howardds/28660700.gif)
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Originally posted by F4UDOA
Widewing,
I understand your point but your fuel loads are a bit off IMHO. The F4U-1 carried 361 gallons of fuel with a range of 1500 miles. It had a longer range than the P-51B on internal fuel and would never practically carry that load into combat.
Also according to the Navy's F-1 range formula the P-51B had approximately the same range as a F4U-1D (550 to 500miles) with only 237 gallons of fuel. When the F4U-1A vs P=51B test was flown they adjusted the weight by reducing the P-51B takeoff weight to 9100lbs to make the ranges equal.
Also the test was flown with the late model F4U-1A at combat power 2250HP. This was essentially our F4U-1D except without external stores pylons.
So to redefine the the test you should reduce the P-51B weight by approx 323LBS and use the F4U-1D at combat power. Also the Hog is carrying 705lbs (2350rounds) of 50cal as compared to 394lbs (1260rounds) of .50cal which was pointed out by the Navy in the test report.
The reduced weight P-51B is noted as "Loading condition #2". The climb chart I posted above is from the exact F4U-1A flown by the Navy in that test.
My numbers are spot on the money. In the TA, the AH2 F4U-1 has a max endurance of 44 minutes using 100% internal fuel (361 gallons). In the TA, the P-51B has an endurance of 41 minutes using 75% internal fuel (202 gallons). If I bump the P-51B up to 100% fuel (269 gallons), its endurance increases to 54 minutes. I believe that a 3 minute difference in endurance is close enough.
Now, I set fuel burn at 2.0 and I took a P-51B with 50% internal fuel, and an F4U-1D with 75% internal fuel. Climb was from 50 feet to 10,000 feet, beginning at 200 mph. The P-51B required 2:55.63 minutes and its climb rate actually increased from 3,100 fpm to 3,450 fpm over the course of the climb. For the F4U-1D, it required 3:06.78 minutes to attain 10k, and its climb rate was relatively steady between 3,000 and 3,100 fpm. The difference in endurance at these fuel loads was about 1.5 minutes in favor of the F4U.
Another factor not generally considered is that the P-51B climbs at a higher speed than the F4U-1D, while the Corsair climbs at a greater angle. This only amplifies the P-51's advantage as it covers a greater distance during the climb, while climbing faster to boot. So, not only does the P-51B get to altitude faster, it opens up a significant distance while doing so.
Unlike the AAF, the Navy calculated ideal range; meaning without considering start-up, warm-up, climbout, combat or reserve. On the other hand, the AAF calculated range, or more accurately, Combat Radius, while accounting for all of the above. They allow for start-up, warm-up, takeoff and climbout. They also factor in 20 minutes of combat time, broken down as 15 minutes at MIL power and 5 minutes at combat power. Finally, they also factor in a 30 minute reserve. Even with all that, the P-51B was conservatively rated for a 450 mile combat radius on internal fuel. I say conservative because with proper throttle, prop and mixture settings, the combat radius on 269 gallons could easily exceed 600 miles, or 1,200 miles round trip and still allow for ground ops, takeoff, climb, combat and reserve.
If we take the ideal 1,500 miles range for the F4U-1 and factor in fuel usage as does the AAF, we can safely reduce range to roughly 70 to 75% of ideal, or a max of 1125 miles. And that is with limiting its altitude to just 5,000 feet, while the P-51B numbers reflect climbing twice as high.
My regards,
Widewing
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Doesn't the Corsair being able to hold its rate of climb at greater angles of attack have its own advantages?
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What was the speed setting for auto-climb? 160mph?
I would have tested the climb with different speeds.
I bet F4U likes to climb with faster speed.
-C+
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Auto-climb is already set by HTC for each plane, at the best climb speed at sea level for that plane(using their FM, might not be the same as the real plane).
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I thought auto-climb held the same rate of climb REGARDLESS of current airspeed.
Anyway, I THINK the Corsair's main advantage when climbing at higher airspeeds (like, in the 350-450mph range) is that she doesn't bleed E in the zoom like a lot of other planes. There's been a (RARE) few times where I've actually been able to pull this off, approaching a target between the 5 and 7-low positions at around 400mph until ~1-1.5k out, then pulling up and rocketing into firing range (even rarer are the times where my gunnery decideds to be on that day and I nail the guy on the first pass).
Corsair also seems to love climbing at AoAs nearing full vertical with enough airspeed, (many times instead of a relatively shallow zoom I've pulled up with a greater AoA than intended with very little back-stick) and around 400-500mph I find I REALLY have to trim the nose down to keep level or maintain a dive without a lot of forward pressure on the stick (I'm talking trim almost fully down).
Waits patiently to be corrected on his analysis.
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Saxman: Auto climb is really "auto speed". Each plane defaults to the best climb speed every time you re-up. You can manually change this once in flight with the ".speed xxx" command.
When you think about it, your climb rate on the deck is going to be vastly superior to your climb rate at 25k, but you'll be doing the same speed.
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Just for clarification, we're talking Indicated airspeed on the auto-speed setting.
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Yes. If you tried to climb at TAS at 15k you'd stall out ( :lol )
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Originally posted by Saxman
Doesn't the Corsair being able to hold its rate of climb at greater angles of attack have its own advantages?
Ask a Zero driver...
Even though an A6M2 will outclimb a P-40, the P-40 driver need only establish a high-speed climb (which means something less than its max climb rate) to quickly out-distance the Zero.
My regards,
Widewing
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WW,
My numbers are spot on the money. In the TA, the AH2 F4U-1 has a max endurance of 44 minutes using 100% internal fuel (361 gallons). In the TA, the P-51B has an endurance of 41 minutes using 75% internal fuel (202 gallons). If I bump the P-51B up to 100% fuel (269 gallons), its endurance increases to 54 minutes. I believe that a 3 minute difference in endurance is close enough.
The Navy test was not with the F4U-1A that is being modeled in AH. The F4U-1A in the Navy test had a paddle prop and 2250HP (2135HP in AH2 1943 version). It may or may not have had the extra wing tanks still in use but it was only tested with 237 gallons which is 100% fuel in our -1D or 75% in our -1A. In either aircraft with 237 gallons of fuel it, it would have a comparable to the P-51B with 180 gallon of internal fuel.
Another factor not generally considered is that the P-51B climbs at a higher speed than the F4U-1D, while the Corsair climbs at a greater angle. This only amplifies the P-51's advantage as it covers a greater distance during the climb, while climbing faster to boot. So, not only does the P-51B get to altitude faster, it opens up a significant distance while doing so.
I would disagree about this depending on the situation. Being able to climb at a steeper angle would be an advantage in close combat. High speed combat is also an advantage to gain seperation. However even Thomas McGuire wrote never to follow a Zero into a slow speed climb with a P-38 that could easily out climb the Zero at high speed.
Unlike the AAF, the Navy calculated ideal range; meaning without considering start-up, warm-up, climbout, combat or reserve. On the other hand, the AAF calculated range, or more accurately, Combat Radius, while accounting for all of the above. They allow for start-up, warm-up, takeoff and climbout. They also factor in 20 minutes of combat time, broken down as 15 minutes at MIL power and 5 minutes at combat power. Finally, they also factor in a 30 minute reserve. Even with all that, the P-51B was conservatively rated for a 450 mile combat radius on internal fuel. I say conservative because with proper throttle, prop and mixture settings, the combat radius on 269 gallons could easily exceed 600 miles, or 1,200 miles round trip and still allow for ground ops, takeoff, climb, combat and reserve.
I don't doubt that it could exceed 600 miles however the P-51B performance charts posted and in AH2 are based on 180 gallons not 269 gallons. At that weight it could not outclimb an F4U-1D at max continous power.
If both A/C were ballasted for the same range AND the same ammo load in AH I have no doubt the result would be different.
I need to retest my results based on some weight issues. My results were much different.