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Excellent question. All I'm saying is wwiiaircraftperformance puts all the information in one place where direct comparisons can easily be made. Your example shows the P-39N with a top speed of 399mph at 9700'. That one line description, while completely accurate, covers only the speed at one altitude, ceiling and no climb figures whatsoever. This would lead the normal observer to think that the P-39N was only a low altitude plane. With wwiiaircraft you can directly compare speed/climb at all altitudes for all the planes. See some of the charts I have supplied. Plus it lists the test criteria and dates. Beats hunting all over for the information. Hope this helps.The actual documents may have been mostly unavailable to the general public, but the data from them could most certainly be found in period books of the time. For instance, here is the performance figures for the P-39N that I gleaned from Combat Aircraft of the World (W.R. Taylor) which was published way back in 1969. See any similarities with your oft-quoted document?
View attachment 487468
The site gives the official govt/military performance tests in print format with graphs on most of the planes. No climb graph for the P-39N but there is a speed graph. The tests in print format offer climb figures for all altitudes up to the absolute ceiling in 5000' increments. No trouble to transfer those numbers on top of the Hellcat climb graphs so they can be compared directly. Also the test in your un-doctored chart are testing non-standard parts (those water injection nozzles) late in the war. The additional Hellcat chart that I provided is from a normal production F6F3 and agrees with the other normal Hellcat charts there. You shouldn't compare a late war test of specialized equipment to a normal production plane.LOL OK surfer boy!
So was the penciled in climb rate of the P-39N available like that from the website?Also, those climb rates given in the un-doctored chart that I provided were possible at normal safe power levels when using ADI so I'm am quite certain that an F6F-3 in service was capable of those numbers at those specific ratings. So again I ask you, do you have more than one official government document showing the remarkable performance of the P-39N that you are so proud of?
And there are many climb charts on the website for the F6F-3. Why only post this particular one? Oh I know, because it's the one displaying the poorest climb performance for the machine...
The problem with being a single type fan boy is that when discussing other types you descend into clichés. The Spitfire was always short ranged compared to the Mustang and others but not in absolute terms. The Spitfire Mk IX eventually had a max internal fuel load of 114 imp gal (136 US)and a total maximum internal plus external of 284 imp. gal (341 US). Its day job was to stop people in Belgium and France going to UK and back, at any altitude from sea level to 43,000ft.The two stage Merlin P-51 only saw combat from Dec '43. The Spitfire IX had the same Merlin engine as the P-51B but weighed 2500# less than a P-51D so its climb rate was absolutely amazing and significantly higher than any of these planes. Great plane if you wanted to go to Belgium and back.
Couple of things, first we seem to get bogged down with engine to engine comparisons. We should be comparing the PLANES to each other. A Hellcat had a 2000HP engine and a P-39N had a 1200HP engine, yet their performance is very similar. Engine to engine comparisons are fun, but the plane performance is more important IMO.I would note that the change of engine in the P-39 was not really a great improvement,
It basically moved the critical altitude of the Allison engine from 12,000ft to 15,500 and gave it around 100hp more at the higher altitudes.
I would note that the Merlin XII engine used in the Spitfire MK II raised the point at which the Merlin made 1000-1030hp by several thousand feet and nobody really claims the SPitfire II was a big improvement over the Spitfire I.
The Spitfire V with the Merlin 45 moved the 6lb boost point up another several thousand feet.
The Hurricane II with the Merlin XX moved the 6lb boost point from 18,000ft on a MK I to over 23,000ft.
Moving the critical altitude of the engine by 3,500ft and still being in the mid teens in late 1942/early 43 is hardly world class.
Also the test in your un-doctored chart are testing non-standard parts (those water injection nozzles) late in the war.
Sorry I'm so stupid especially after all you guys have tried your best to help me. Sorry again for my posts quoting facts direct from government/military tests or the pilot manuals.Lots of dead electrons in here. Having gone through this thread again, I still don't think you understand how a supercharger works, I don't think you understand how range works for mission planning. You have steadfastly refused to understand how shit works when explained by some very knowledgeable folks. You realize that virtually everyone here knows who Buzz Wagner, George Welch et. al. were, what WEP and the little wire is, where to find info on wwiiaircraftperformance, none of this is groundbreaking stuff here.
You are and entitled to your opinion and you have tried to back up arguments with some facts but they have been constantly refuted and still the circle argument goes on. I'm beginning to find it laughable that apparently the AAF, RAF and virtually everyone else except the VVS ( for very good reasons stated by others ) were all stupid to pass on this amazing war winning plane.
If it was so hot, why wasn't it used for escort in the ETO by 8th FC? Why couldn't it intercept Japanese bombers over Guadalcanal ( when the F4F could )? Why did virtually EVERYONE dump it in favor of at least the P-40 ( if not something even better ) the first chance they had?
Eh, good luck, and as I said earlier, Peace Out.
A Hellcat had a 2000HP engine and a P-39N had a 1200HP engine, yet their performance is very similar. Engine to engine comparisons are fun, but the plane performance is more important IMO.
Yes, we all get it that the P-39 was fast for the amount of power available. But it came at a huge price. It had many deficiencies that were basically non-existent in other US fighter aircraft of it's time. Lack of useful range and payload, light construction (compared to other US warplanes) which made it far more vulnerable to enemy fire, and substandard armor protection for both pilot and engine, just to name a few.
Sorry I'm so stupid especially after all you guys have tried your best to help me.
Many accounts speak well of it's construction or protection or I am reading the wrong ones?
The 110 gallon tank was used initially in late 1943 on P-47C/D C/L but AFAIK never on the P-39. First used on P-51B in May 1944.Can we please use the normal 120 gallon internal capacity? PLEASE. The 87 gallon capacity was at the request of the Russians and only used on some N and Qs. A SPITFIRE had more range than a P-39 with 87 gallons.
The 110 gallon drop tank was in extensive use with the 8th AF in England and in the Pacific.
Thanks to everyone for their replies and comments.
I get a bit suspicious when small changes in an aircraft make huge changes in performance.
I will even grant that the P-39N had 150-160hp more at the higher altitudes but the climb figures don't track well.
I will try to post the relevant figures later.