Best fighter in Eastern Front, 1943.

[CORSNING]

Shortround6,
A lot of what you have said in your last two post is true. Most manufacturers overestimate their product. They build a prototype that reaches the goals set. Then the military (any country) steps in and begins to add equipment they deem necessary for their needs. You made a comment in post 97 stating the USAAF figures for the P-63 speed using W.I. are 30-40 mph less than the manufacturer's data. Can you supply both documents you are referring to?
I have checked several sights and reference books on the performance of the P-63. I have an extremely hard time believing what they have published: P-63A - 1,500hp. Max speed: 410mph. Climb: 25,000ft/7.3min. Normal Gross Weight: 8,800 lbs.
P-63C - 1,800hp.W.I. Max speed: 410mph. 25,000ft/8.6min. Normal Gross Weight: 8,800 lbs. Odd, isn't it. So the speed on what appears to be a military graph do not surprise me at all. You mentioned in post 99 that the figures on the graph don't show up anyplace else. Yea, you're right. Now the real question is, WHY NOT? The graph performance actually seems the most realistic compared to any published figures I've seen yet.

 

[CORSNING]

Bell sales man? Well if it is he made some pretty stupid mistakes posting the P-38H: 436mph and 4,700fpm. I mean why is he posting a plane of superior performance if he is trying to sell his product? WOW and adding the XP-51F has got to be a blunder in getting a raise. And why is it stamp CONFIDENTIAL FOUR TIMES? He doesn't want his wife to find out if he does get a raise?

 

[Juha]

I in the end voted for 109G, I still cannot choose between La-5FN and Bf 109G, but La-5FN had got enough votes, so I decided to vote for 109G in order to redress the balance and why 109 and not 190A? Because of Soviet fighter pilots usually thought that 109 was a more dangerous opponent to them than 190. Against Il-2 190A was better because of its heavier armament, even if 109G-?/R6 almost redress the balance, and because of its radial engine.

Juha

 

[Juha]

....It makes the P-39 data rather suspect without a second source.

see http://www.zenoswarbirdvideos.com/Images/P-39/P39TOCLC.pdf

For climb using military power.

Hello Shortround
you have already given a second source, Ray Wagner's American Combat Planes, which gives P-39N top speed 399mph at 9700ft, climb 15,000ft/3.8min and for P-39Q, no info on block number but the accompanied photo shows under wing .5 mgs, 385mph at 11,000ft and climb 15,000'/4.5min.

Juha

 

[CORSNING]

Juha,
You are absolutely right about the Il-2 crew fearing the 190's firepower. No one can second guess you for picking the 109. It was a very respected aircraft by the VVS.

 

[CORSNING]

I've moved to a different room in the house, so my files are a little....no they are a total mess. It is hard for me to find what I'm looking for right now. I hope to rectify that this weekend so that I can put together a side by side comparison between the La-5FN and the BF.109. I have plenty of info on the 109 but it would help if someone could tell me which model (G-1, G-2, G-6) I should be searching for......any ideas guys.

 

[CORSNING]

I forgot to redress the better performance at higher altitudes of the P-39N over its predecessors. A new supercharger gear. I'm taking a SWAG here because I can't find the file...yet, but it stepped up from 8.8 to 9.6 (boy that's a real guess) allowing it to retain its performance at higher altitudes.

 

[Juha]

I've moved to a different room in the house, so my files are a little....no they are a total mess. It is hard for me to find what I'm looking for right now. I hope to rectify that this weekend so that I can put together a side by side comparison between the La-5FN and the BF.109. I have plenty of info on the 109 but it would help if someone could tell me which model (G-1, G-2, G-6) I should be searching for......any ideas guys.

Hello Corsning
G-4 and G-6 were the main sub-types in 43. Because the main difference between G-2 and G-4 was the better radio in G-4, G-2 performance was the same as that of G-4. before Oct 43 max allowed boost pressure was 1.3ata but on July 43, when 1.42ata T/O and emergency rating was briefly allowed

Juha

 

[CORSNING]

Thank you Juha,
I'll probably use the G-2 or G-6 performance because I'm not sure I have anything on the G-4.....I might but no promise.
I apologize ahead of time guys because all this computer stuff an using this sight are new to me. The best I can do is decipher graphs and and post results at this time.

 

[DonL]

I also see the Bf 109 G6 as the preferd model. But please a G6 in fighter configuration without external weapons, like the 2 151/20 Gondeln. At the eastfront the Bf 109 G6 was much more flown as pure fighter instead against heavy bombers.

 

[Shortround6]

Hello Shortround
you have already given a second source, Ray Wagner's American Combat Planes, which gives P-39N top speed 399mph at 9700ft, climb 15,000ft/3.8min and for P-39Q, no info on block number but the accompanied photo shows under wing .5 mgs, 385mph at 11,000ft and climb 15,000'/4.5min.

Juha

Thank you but something still isn't right. Many other sources give 376mph at 15,000ft for N and 357mph at 10,000ft using military power. Granted the WEP is 1420hp instead of 1125hp but according to the cube law you need 1564hp to hit 399mph at 10,000ft if I did the math right. 1420hp should get you to 385mph. This is assuming the drag coefficient stays constant.

The Climb graph in "America's Hundred Thousand" shows a climb rate of about 3300fpm using "combat power" (1420hp) up to a bit over 10,000ft at which point it falls off to about 2500fpm at 15000ft. Time to 15,000ft is about 5 minutes. This is for a weight of 7,570lbs. Now maybe this is a bit low but 3.8minutes to 15,000ft is nipping at the heels of a MK IX Spitfire with a Merlin 66 using 18lbs of boost. The planes are within a few hundred pounds of each other but the Merlin is making 1710-1750hp at low altitude, it falls a bit but after shifting to high gear it is good for 1580-1625hp at 12,500ft. At that altitude the Allison should be good for about 1275hp. While the Spitfire does have more drag than a P-39, the Spitfire is going to have to have an awful lot of drag to cancel out it's power advantage in climb.

The Figures for the "Q" don't sound too bad but since the N and the Q used the same engine for all practical purposes and since the Q basically swapped 4 internal .30cal guns for two podded .50 cal guns that performance drop for the Q doesn't sound quite right. It isn't until the -20 block that the Q really starts to out on any weight compared to an N and that is compensated by the fact that form the _20 on the wing .50s are not installed.

 

[Shortround6]

I have checked several sights and reference books on the performance of the P-63. I have an extremely hard time believing what they have published: P-63A - 1,500hp. Max speed: 410mph. Climb: 25,000ft/7.3min. Normal Gross Weight: 8,800 lbs.
P-63C - 1,800hp.W.I. Max speed: 410mph. 25,000ft/8.6min. Normal Gross Weight: 8,800 lbs. Odd, isn't it. So the speed on what appears to be a military graph do not surprise me at all. You mentioned in post 99 that the figures on the graph don't show up anyplace else. Yea, you're right. Now the real question is, WHY NOT? The graph performance actually seems the most realistic compared to any published figures I've seen yet.

Part of the problem with the P-63 is that it used two engines that would up being almost identical in power output. The -93 engine in the "A" was not initially cleared for use with water injection but was at a later date. The -117 engine in the "C" was always cleared for water injection. Both engines were rated at 54in MAP for military power 91325hp, both were rated at 60in dry (1500hp)and both were rated at 75in wet (1820hp). That is were the extra 320hp for the -117 comes from. Once the -93 was cleared for water injection it was good for 1820hp.
The next problem is that these are sea level ratings. power started to drop as altitude was gained. by the time a P-65 got to 15,000ft it had about 1500hp wet, about 1325hp dry and and about 1250-1275 Military. By the time you get to 25,000 ft there is little or no difference between military power and anything else. the supercharger cannot supply any more pressure than the military rating. Use of water injection can boost power a little due to the cooler intake air being a bit denser but the manifold pressure is nearly the same.
Performance data for the "A" and "C" can vary due to when it was taken and under what conditions. Once the "A"s are cleared to use water injection there won't be much difference in performance.
The US also changed climb performance measurement. Many planes were rated using take-off/military power for 5 minutes with power dropped back to max continuous for the remainder of the climb.
Some planes were rated using take-off/military power for the entire climb and others were rated using combat power (WEP).
Unless the chart or author specifies what power was used things can get very confusing.

 

[parsifal]

great info on the p-39 guys.......I am awed and amazed

 

[Juha]

Hello Shortround
I know that even Pilot's Flight Operating Instructions for Army Model P-39Q-1 Airplane gives 385mph for P-39Q and 379mph for -39N, which is odd because systems and weight graphs/tables in the booklet incl the underwing mg pods for the Q, the main difference between the subtypes at that stage and IMHO the 4 integral wing .300 mgs were less draggy than 2 underwing .5 mg pods and the engine was the same.

I know the graph in Dean's book, but even if I valued my copy of the book very much the same Graph 21 gives a time of climb graph for P-39N and Q at 7570lb at combat OR military power, which is odd.

On the other hand a Soviet speed graph gives P-39Q-15 with 100oct fuel max speed of appr. 601km/h (373.5mph) at appr. 5000m but the same graph gives max speed for Spit LF IX (Merlin 66) as 642km/h (399mph) at appr 6285m.

Juha

 

[CORSNING]

Sorry it took me so long to get back. Finding performance figures at 1,000m intervals that are realistic for the La-5FN wasn't easy. There is plenty on the Bf.109 so it was hard to figure out which were used on the eastern front in 1943 but I think I've come pretty close. I chose the Bf.109G-2 because its performance in 1943 from info I have was slightly better than the G-6. But you have to keep in mind it was using 7.9mm machine guns instead of the G-6's 13mm (at least at that time and place).
Information on the Bf.109G-2 comes from the following sources:
1. Warplanes of the Third Reich.
2. Finnish Air Force performance trials (MT-215.?).
3. What appears to be VVS performance comparison graphs.
Information on the La-5FN comes from the following sources:
1. Soviet Air Force Fighter Colours 1941-1945 by Erik Pilawskii.
2. What appears to be VVS performance comparison graphs.
Performance speed/climb:

Altitude Bf.109G-2 La-5FN
S.L 326mph/4,590fpm 366mph/3,985fpm
1,000m 348mph/4,192fpm 375mph/4,330fpm
2,000m 364mph/4,861fpm 385mph/3,857fpm
3,000m 374mph/3,660fpm 384mph/3,325fpm
4,000m 380mph/3,385fpm 382mph/2,853fpm
5,000m 382mph/3,385fpm 380mph/2,750fpm
6,000m 396mph/2,972fpm 392mph/2,253fpm
7,000m 413mph/2,696fpm 381mph/1,805fpm

The only big problem I had was both their climb rates at 1,000m. I believe the Bf.109G-2 is underestimated and the La-5FN is overestimated at that altitude. But I chose not to deviate from the documents on the 109 and not to deviate from the graph on the 5FN.
The 109 is using a maximum boost of 1.42ata and the 5FN is using its 10 minute boost.

 

[CORSNING]

There is a few things to add about the La-5FN in September 1943. It began to be produced with all the refinements built in and not just piece work on the assembly line as it was in May 1943. Its aileron response now exceeded the Yak-9, control harmony was excellent and stick forces were light and effective right through the flight envelope. I'm not going to elaborate on the Bf.109G-2 because I've read too many posts on this sight that tell me there are other people WAY better qualified than I on that subject.

 

[claidemore]

Whoa there bubalooie!
Bf109G2 climb rates are nowhere near 4000 ft/min, definately not over that number. 109K4 with 1.98 ata could do that, but a G2 or G4 is going to be about 3600 ft/min @ low alt, based on G1 stats from this page Kurfürst - Mtt. AG. Datenblatt, Me 109 G - 1. Ausführung
A 109G6 could reach 20000ft in a little over 6.5 minutes, or an average of 3027 ft/min climb rate. A 109G2 would be about 3400 ft/min average climb rate to 20000 feet.
Check this page: Kurfürst - Flugleistungen Me 109G - Baureihen
The speeds you have listed for the 109 look about right, but maybe there was a calculation in the climb rates going from metric?
I don't believe 1.42 ata was released until September of 43 (I think October is a generally agreed on time) as well.

For the La5FN it should be 4330@sea level, and 5.2 minutes to 5000 meters, which equates to 3153 ft/min averate to 16000 ft.
for quick reference these links: Lavochkin La-5FN Russian Aviation Museum

Basically a G2 would have an advantage and a G6 would be at a disadvantage in climb rate vs an La5FN until late 1943.

 

[CORSNING]

claidemore,
I am no where near an authority on on the Bf.109. Kurfurst is without a doubt THE authority on that subject. I knew I was going to be stepping into IT BIG TIME. BUT Kurfurst is where a lot of the info came from. (Sorry for not asking first Kurfurst). OK, lets start with the 109. William Green in Warplanes of the Third Reich lists the Bf.109G-2's initial climb rate at 4,590fpm. Climb to 2,000m/1.5min.(4,373fpm.avg.).
13,120ft/3.2min.(4,100fpm.avg). Finnish Air Force performance trials MT-215 give the G-2 a climb to 1,000m of .8min.(4,100fpm.avg.). And just for icing on the cake Rechlin E'stelle Test Nr. 1586 lists the climb rate of the Bf.109G-1 at: 4,113fpm/S.L. 4,113fpm/1,000m. 4,113fpm/2,000m. Like I said, I am no authority on the Bf.109. That is why I did some heavy research.
Now as for the La-5FN, I saw the graph floating around this sight: 4,337fpm/S.L and 4,330fpm/1,000m. However, I decided to go with the author of Soviet Air Force Fighter Colours 1941-1945, Erik Pilawskii. He is a scholar of Russian aircraft of WW2 and has spent many years in Russia researching. He began his studies there in 1987 and was granted access to previously inaccessible key Soviet archival collections. He published the figure 3,985fpm as the initial climb rate and I have no intention of second guessing him. Lets say the La-5FN performance was as flexible as VVS earlier aircraft and deviated as much as 5%. That would open the door for an initial climb rate of as much as 4185fpm. Sorry but 4,300fpm was La-7 territory.

 

[CORSNING]

Tid bits: The "standard" La-5FN of late 1943 could reach 5,000m/4.6min. (3,565fpm.avg.). Since early spring of 1942 the Bf.109G-1 and on had provisions for GM-1 boost. The Bf.109G-2 at 6,834 lbs. could reach 19,685ft/5.1min.(3,860fpm.avg). In 1943 the 109 on the eastern front was the Climbing King. Challenged only by the P-39N at some lower altitudes. Most of the fighting was at these lower altitudes and that is what made the Airacobra so valuable to the VVS. The 39 could hold its own in the vertical plane and had an edge in the horizontal. Two points of 1943: 1. The 109 was ruler of the sky over 6,000m. but that is not were the vast majority of action was on the eastern front. 2. At low and medium altitudes the 39N was in its glory and could hold its own (or better) to anything it met in 1943. Of course this all changed later in 1944, but we are talking about 1943. The Russians were flying to win so they did "push" their Allison motors. So keep in mind, any published figures you see for the P-39N/Q are not quite up to the figures that VVS pilots were squeezing out of their Airacobras.

 

[CORSNING]

I've been thinking. Yea, it hurts when I do that. I looked at the pole results so far, and it just isn't right. The 109, 190, 5FN and the Yak-9 were all excellent fighters in 1943. They all did there job. But the p-39N was as rugged and resilient as the 190 even though it was a liquid cooled engine. I've already stated its superiority in performance. The 109 had its advantages, but the N had the ability at lower altitudes to neutralize them and gain control. I need to study the La-5 (7,323 lbs) more before I even make a SWAG. But, the Airacobra (6,900-7,000 lbs) could outclimb it, at least dive with it and had a 37mm punch. I need to do more reading before I can say it was as maneuverable. But the US P-39N minus about the 500 lbs that the Russians ditched was a very maneuverable aircraft. It was no longer the overweight, underpowered Airacobra of 1941-42. Just ask the F-4U pilot that flew in trials against one.