Aerocobra!

[humble]

The original design was unarmoured (1939). Production specs called for addition of armor. The D was the 1st production run (923) so the 245 might be total weight....not sure since no specific "total weight" could be found for armor on the D or C. From what I can find the C should have had armor already since it was the preprodution (20) run. Armor weight also technically includes self sealing tanks and armored glass. The P400 (roughly 400) was a different configuation manufactured for england. The british used significant armor so its possible design specs were different. It had the 20mm instead of the 37mm but no specifcs on other mods if any. Basically it was a P39-D1.....

[Krusty]

At a whim I returned to this thread to check up on it (it's got a new page). While not descending into the intelectual abyss to fight with a select few, I will point this out:

Humble: The quotes aside, you make one argument several times. The P39 was used by the elite, who had their choice, so it must have been the best. The P39 was in fact inferior to the yak9s, and the la7. The La was by far one of THE best planes of the entire war (across all nations, it was equal to the best any other nation could provide). The Yak was also a very high-performance machine, so much so that the LW weren't alowed to fight it below ... what? ... 25,000 feet. Both of these planes were far far better in every way to the P39's performance.

You can't just assume that "the elite chose it, so it must have been one of the best," as an argument. There are probably many reasons for this. The P39 being superior to all other planes is not on this list. They began flying with these planes. Perhaps nostalgia, if not for the P39 they'd all be flying biplanes and dead many years back. Maybe they had an irrational appreciation for the plane that saved their lives (even US pilots had this problem). My guess? Ammo load. Availability. For one, the Yaks had very small ammo loads. You might get 1 kill, maybe 2 before having to return. I bet for the elite squadrons that would be frustrating to no end. Availability means they had SO many they could throw away the engines every 3-4 hours and replace them. They were a disposable plane with unlimited replacements. LA7s and high-end Yaks were in high demand. Lose a few, and the pilots of the "elite squads" have to revert to other planes (thus disrupting efficiency) probably also annoying to no end for a productive unit.

That one argument doesn't hold water.

[humble]

Krusty

There was tremendous pressure for the top aces to switch to the la-5 or other soviet design. The simple reality is that they preferred the P-39 over any plane available. Once again your making statements without any documentation. The P39D is a 1942 plane. the La-7 and late war Yak-9 are both 1945 era birds. The P39Q was a mid 1943 release and the workhorse of many vvs units. The Q got to 25,000 5 minutes faster then the P-51D and handled better then any fighter on the eastern front. It could eat up a 109G6 or la-5. It retained almost all the pure turn performace of the D (which could easily out turn the best turning 109 (the E) with siginifcantly better overall speed and climb. Numerous commentary is available in interviews directly with many soviet WW2 era aces who clearly state that the P-39 was easily the best fighter available to them in 1943-44.

The airwar on the eastern front was never fought at 25,000. Almost all actions were at 15,000 or lower. The laag-3 and La-5 were both very high production run aircraft. Stalin was so disappointed in the Laag-3 he shut the factory lines down and converted them to the Yak-7. The remaining laag-3s were modified and the la-5 was born. It proved to be very capable and was put into service in 1942.

Its obvious from your writing you no very little about russian aviation during WW2. The soviet military awarded eleite status to units only after significant battlefield success. This was not only a tremendous honor (similiar to US presidential unit citation) but also gave the unit priority on equipment and the ability to "requisition" skilled personnel. The catch was that these units then became the "hammer" in the soviet army, constantly thrown into the toughest battles. As it relates to the airwar the Guards units were given top priority and could fly anything they wanted...they  WANTED the P-39. I'm amazed at your inability to realize the simple truth. The P-39 was simply one of the best mid altitude fighters of the war. The Q could do roughly 400 mph and turn about as well as a spit V.

[TimRas]

Originally posted by humble
All you need to do is look for it, you can read between the lines in accounts like Grislawski's and find "official" mention elsewhere.
...
your numbers on the armour are just wrong. The P-39D had 245 lbs of additional armour. This was in addition to the original amount. This is pretty typical of what I see here with regard to inaccurate "statements of fact".

Sorry, "read between the lines" is not what I would call substantial.

I have the weight breakdown of P-39Q-1-BE (from the Flight Manual, Zeno's may have it also):
Armour:
Gear Box: 70.7 lb
Fume : 27 lb
Windshield: 8,2 lb
Turnover: 15.8 lb
Inst board: 2.8 lb
Oil tank:  29 lb
Aft cabin: 18.2 lb
Windshield(glass): 21.7 lb

Total:  193.4 lb

What did I miss ?

(For comparison F6F Hellcat, much bigger and heavier plane, carried a total of 456 pounds of armour plate, toughened class, Duralumin deflector plates and self-sealing material for the fuel tanks).

[Bronk]

And the beat goes on.


Well batty care to comment on the P-39 .






Bronk

[Krusty]

Originally posted by humble
Krusty

There was tremendous pressure for the top aces to switch to the la-5 or other soviet design. The simple reality is that they preferred the P-39 over any plane available. Once again your making statements without any documentation.

I could quote anecdotal pilot's memiors 60+ years after the fact, but it's been proven many times that the la5 was a better plane than the p39 in many ways. Look at the performance charts. Like I said, you can't just say "They preferred the p39 so it's better" -- because there's many many reasons to prefer a plane. Maybe they "preferred" it because the engine kept them from getting shot with bullets, if hypothetically so that would mean they were being shot more often than doing the shooting, and the wingman tactics won the battle, not the plane itself (hypothetically). You can't just say "it was preferred" and leave it at that.

It could eat up a 109G6 or la-5. It retained almost all the pure turn performace of the D (which could easily out turn the best turning 109 (the E) with siginifcantly better overall speed and climb. Numerous commentary is available in interviews directly with many soviet WW2 era aces who clearly state that the P-39 was easily the best fighter available to them in 1943-44.

Okay, show me a turn radius or turn speed chart that shows the P39 turning tighter than the 109E. Just because pilots DID out turn something doesn't mean the turns were equal, or that they both started flat, at the same time, or any number of circumstances. Even Porkyshrin's own motto was altitude-speed-manuver-fire. He developed tactics to dive from high alt onto the target then fire and get out. How much of a turn are you going to get on a 109E with this setup? Is pulling lead for 10 degrees a turn? 45 degrees? Pilots only report what happened at one time. They often don't include all the details in the reports. Any plane can out turn any other plane given the right circumstances. 190s were reported to turn with spitfires, and WIN. Doesn't mean the 190 turns better. Just means the pilots flew it better in that fight.

The airwar on the eastern front was never fought at 25,000. Almost all actions were at 15,000 or lower. The laag-3 and La-5 were both very high production run aircraft. Stalin was so disappointed in the Laag-3 he shut the factory lines down and converted them to the Yak-7. The remaining laag-3s were modified and the la-5 was born. It proved to be very capable and was put into service in 1942.

Its obvious from your writing you no very little about russian aviation during WW2. The soviet military awarded eleite status to units only after significant battlefield success. This was not only a tremendous honor (similiar to US presidential unit citation) but also gave the unit priority on equipment and the ability to "requisition" skilled personnel. The catch was that these units then became the "hammer" in the soviet army, constantly thrown into the toughest battles. As it relates to the airwar the Guards units were given top priority and could fly anything they wanted.

I'm aware of all this. Please don't condescend, or make statements like "it's obvious you know nothing". I never typed anything to counter the points in the above paragraph.

..they  WANTED the P-39. I'm amazed at your inability to realize the simple truth. The P-39 was simply one of the best mid altitude fighters of the war. The Q could do roughly 400 mph and turn about as well as a spit V.

Hrm.. turn about as well as a spitfire? Show me where. Also the top speed was 380 at top altitude (15,000+). 20mph is a big drop from 400mph. Even the hellcat could do about 400mph at alt. At 5000 feet the P39Q (yes, not the D, the Q, with a whopping 1,200 hp engine) could only muster 330mph. 109s were almost 50mph faster (109G-2s doing about 375mph at this alt). Like I said in my previous post, they wanted the P39, but not because it was the best-flying plane around. There were other planes that out performed it. There is enough evidence to show that. They wanted it for other reasons, is my guess. You seem to think that "wanting it" equates to it being the best. Not always so.

Nobody's arguing they got things done in the P39. Hell the Finns got things done in a Brewster Buffalo. Doesn't mean the plane was very good. What you're doing is taking one biased, pilot's-memory-based writing on the matter and trying to turn it into data to show that plane X did Y. That's why everybody brushed you off years back in the other threads. You take one anecdotal source and use it to prove the moon is made of cheese. Your "proof" isn't proof at all. It's just quotations from a book. That's what I'm trying to get at here.

My point isn't that the P39 was a total POS. I think it had lackluster performance, personally, but my point is that your arguments that it's uber are unsubstantiated and not supported.

Get charts. Get test flights. Get actual data, speeds, turn radii, THEN say "okay, looks like this shows the P39 turned better than a yak3, but worst than a yak9". That type of thing.

[Krusty]

Also, the game IL2 is known to not have the most representative flight engine. They are overly-generous to almost all Soviet aircraft. They have it modeled so that the P39Q (listed as 1,325hp) gets to 10k in 4.0 minutes. Most planes can reach 15k in this time. That's just 2500fpm. I doubt it's climbing any faster than a P51 to any altitude. Please support that with some numbers.

[humble]

and how it would/should perform in AH. I'm using gonzo's page as the point of reference for performance.

The only hard comparative data for the p-39 vs any currently modeled plane is the 109E. The P-39 was noted to be clearly superior in everything but climb. It could totally dominate the 109E in turn taking only 720 degrees (2 revolutions) to lap the 109E. The P-39 Q has more power but almost identical weight and therefor wingloading. Speeds and climb rate reports vary on sources I have from 375 to 398 mph and climb ins generally in the 2500ft/min.....

The 109 E has a noted turn rate of 544 and 403 respectively, significantly better then the 620 & 462 of the La-5fn. Given the degree of domination the P-39 had over the 109E I'd speculate that its turn rate will beat the spit V (503, 386) and approach the A6M2's 378, 318 numbers. How close is pure speculation but going from the comment above that the p-39 was "every bit the match" for the zeke at its optimum alt I'd guess somewhere in the 460-490, 380-420....but again just a guess.

The la-5n's speed actually drops off from 8 to 16k so its performance at the "prime window" for the P-39 is actually somewhat nuetered.

Worst speed at alt numbers i have for the P39Q are 376 mph at 15,000 which would be roughly even with the La-5 as modeled in AH. The D was 368 at 12,000. Now these are US #'s and the russian birds were lighter and ran at higher man pressure. Based on what I can read from soviet sources the P-39 performance equaled or exceeded the la-5FN which is actually a very late 1944 bird as modeled. It is far superior to the La-5 in service in 1943.

Again this is just some extrapolation based on what I can find. But when you cobble it togeather you have plane that turns exceptionally well (based on the british tests vs the 109E) and is reasonably fast (worst case is 368 at 12,000ft) and somewhat limited in the vertical. The russian 1st hand accounts seem to indicate significantly better climb then indicated by US numbers but no actual data seems available online that I could find. Given its good dive characteristcs I'd say a 15k P-39 would be a very fromidable adversary...

[humble]

If you read what was posted earlier you'll find reference to british tests at duxford with a captured 109E. P-39 could gain 360 degrees in 2 revolutions...

As I stated the raw numbers on the P-39 vary....and no clear numbers on performance as modified by the russians are available that I can find. All we know is the russians ran the bird "hotter" and got better performance at the expense of additional wear and tear on the engines...

Performance charts on what la-5....show me performace numbers for the la-5. The la-5FN we have in AH is a late 1944 bird thats functionally close to the 1st la-7's. The P39's were discussing are 1942/43 birds.

Its well documented that the british readily admitted the p-39D was more then a match for the 109E in everything other then climb under 20,000ft.

Why dont you show me one single piece of 3rd party data on ANYTHING. I've supported the vast majority of everything here.

[humble]

Originally posted by TimRas
Sorry, "read between the lines" is not what I would call substantial.

I have the weight breakdown of P-39Q-1-BE (from the Flight Manual, Zeno's may have it also):
Armour:
Gear Box: 70.7 lb
Fume : 27 lb
Windshield: 8,2 lb
Turnover: 15.8 lb
Inst board: 2.8 lb
Oil tank:  29 lb
Aft cabin: 18.2 lb
Windshield(glass): 21.7 lb

Total:  193.4 lb

What did I miss ?

(For comparison F6F Hellcat, much bigger and heavier plane, carried a total of 456 pounds of armour plate, toughened class, Duralumin deflector plates and self-sealing material for the fuel tanks).

Posted afterward, you might actually be correct here. The original design did not have armor. The C may or may not have had any. The D had ~ 245 "added" (from zero or did C have any?). The Q was the real 1st production run and armor weight was reduced. So the Q weight is right on with your earlier comment. The planes in use at kuban were either the D's or the 400's...the D-3 had more armor then the D1 & 2....I have no clue what the british specs were. The 700lbs comes from a guy well regarded as an expert (who by the way thinks the P-39 is junk). He simply like me is curious how it performed so well. I'd guess off hand that the "700 #" number is the total wieght stripped from the birds in question. Funny how the guys in pac and russians reached the same conclusion. Strip out as much weight as you can (remember they took 2 or 4 30 cals out as well)....I wonder if the pilots ran them hot in the field like the russians did.

But I agree my comment on weight was in error, which I tried to correct above. I think the total weight removed is right...but agree the bird doesnt appear to have that much actual armor weight. But the Q was significantly lighter in armor weight then the D...that I do know....

[B@tfinkV]

well bronk, i dont give a toss about the P39 whatevercobra, and i dont think a couple of others here do either.



now there are people like humble who are arguing with krusty about solid facts and this i find totaly normal.


what i think is pathetic are the people who jump on the band wagon when someone is being flamed.


If you came into this thread and said nothing of value about the topic, and furthermore just made fun of krusty for his mistakes, then you are far more useless to this debate than krusty.



thats just my opinion, and i shall not be reading any further posts in this thread.

[humble]

I have zero issue with Krusty, he's a great guy and I fly with him all the time. I just dont agree with his thoughts on this particular subject. Obviously there is no need to beat this to death....here is a bit more food for thought.

La-5

This is a link to a russian site with english translation. The data page is for the la-5....note the difference in the la-5 and la5FN. Also that the La5FN has two distiinct sets of numbers since the later la-5FN has a much more powerful engine (same as the la-7 I believe).

La-5FN

The la-5fn we have here has the ASh-82FN engine (99% sure)...same as the La-7.

This is a link to an interview with Ivan Kozhedub, he recieved his LA-5FN in may 1944. Prior to that he comments on the Lag-5 (which I think is the La-5). so the La-5 FN's with the more powerful engine are mid 1944 birds...

 interview

Finally the same russian site has some data on the P-39


P-39

I noticed a couple of things...

climb to 4500 meters (14,650ft?) is 5 minutes...or 2975 ft/m....better then the raw US numbers. Max speed is noted at 615km/h and horsepower at 1420

This gives the P-39 a higher speed 615/580 then the la-5 and close to the la-5fn (634). The la-5 climb rate works out to 2850 ft/m...less then the P-39. The la-5FN is substancially better using the faster climb rate 3457 ft/m but using the lower # (different engine??) we get 3066 ft/m which is very close.

The numbers on this site clearly show the speed and climb performance of the P-39 to be roughly equal or superior to its russian counterparts (1943) and competative with the original la-5FN. Combined with the british evaluation of its turn capability I'd say its pretty clear you have a plane thats reasonably fast, climbs reasonably well and out turns anything it would run into. Using the russian supplied 1420 hp can we extrapolate out performance numbers??

[Krusty]

The Q-1 had reduced armor, but I believe by the Q-5 or so it was re-instated as standard. They needed it, apparently.

Question, though... Why would a 1943 plane be compared to a 1941 design? It's much heavier than a 109E, but only has the same horsepower. While slightly aerodynamic, by the time it saw some action in 1943 (and later) it would be up against 109G models, much more advanced than the early E.

I will admit that it probably had a tight turning radius, but it also had major stability problems, including spins (if you don't get out in the first 1/2 oscillation, you may not ever get out of the spin -- I have a scan of a page off the flight manual saying this). Most older designs do have a tighter turn radius, because of power available and the speed of the turn. However, I posted already they had good turners. They had some of the best turners. If they only wanted to turn, they would have used what they had. Porkryshin liked the P39 because it opened up tactics to him. No longer would they just turn in the flat plane. He developed tactics in the vertical that were not possible before the P39 showed up. He liked that the P39 allowed them to develop BnZ tactics, which were (before the 39 showed up in 1942) almost impossible. The 109s it tangled with were primarily geared for the 20k alt band, but that's not to say they were handicapped below this altitude.

So the P39 was a match for the 109E, let's say. Taking the data for the 109s in AH:

http://www.gonzoville.com/ahcharts/index.php?p1=109e4&p2=109f4&p3=109g2&p4=109g6

We find that it is slower, climbs worse, and the only benefit it has is turn (but, this is the 109, not the P39, don't have actual turn on it)

Going from P39D flight tests:


The P39 climbed far worse than the 109E, but a little faster, doing about 355 at 13k



But, seeing as it would be up against F4s, G2s, and G6s, by the time the Soviets got them, going back to the gonzoville chart above (note that's an early G6 model for AH) we see it is still far below that of the 109s it would fight against.

Soviets loved propoganda. They loved fights where the underdog prevails. There are cases where Soviet "hero" pilots were said to have been shot down in 12-on-1 engagements when they died, but that was the cover story for dying to a 1-on-1 (as with Lytvak), or even when attacking a lone Ju87 as with Shestakov. Why is it only the Soviets say the P39 was a beast? Perhaps because they loved their propoganda. You can't just say "oh they lightened their load" -- because WE tried that too. The P40N had a much more powerful engine and a much lighter weight (even removing 2 of the 6 guns) and still was lackluster compared to what was already in service. The P51H was a stripped down, weight-saved version of the P51 and it really didn't gain all that much performance. Yes, there was a gain, but it wasn't miraculous, as with the Soviet P39.

Was the P39 underestimated? Sure. Was it the super plane the Soviets show? Naaah. You've still got an overly-heavy 1941 design with only 1200hp and a terrible gun (worst of the war, basically) barely able to climb at all, a top speed not much to write home about, and only able to compete with LW planes "between 8k and 12k" -- a very narrow band, indeed. A single zoom climb or power dive can get you past this zone very quickly. The Q model had only 50hp more than the D (1150 vs 1200hp), but had a 4-blade prop, so it was a little faster. That would mean a little more climb rate, but not 4500fpm like the 109s it was up against. Forget about the even-faster 190s that eventually showed up.

Link to image with engine HP chart

[EDIT] Changed "P47N" to "P40N"

[EDIT2] Fixed second image, pasted wrong code

[Krusty]

The info on that page might be wrong. For the "1400hp" engine, it states:

"2 X PE V-1710-85 Allison"

2 of them? It must be confused with the P38.

It also states a 32mm cannon. It was 37mm. I think we have to discard that horsepower rating due to those two flaws. Note that even with such a super high rating, its top speed is still listed at 385mph or so, a little higher than the norm (+10mph) but that its rate of climb to 13,500 feet is 5 minutes (2700fpm). The hp might be wrong, but the performance itself seems to be near milspec.

It lists the Lavochkin speed at sea level, but not the P39 speed at sea level. So just going by top speed alone might be mis-leading, but the 1943 -FN surpasses the P39Q at 18,700 feet or so, about 5k higher than the p39. I'm not sure how that breaks down, speed-wise. In the AH speed chart it does about 360 at sea level. Using the speed chart in my previous post (fixed, btw) we see that the 39D did a bit over 320MPH at sea level. The Q seems to be about 20mph faster, so let's say it's 340mph at sea level. That's still slower than the LA5FN. Even the 1942 LA5 comes out to about 334mph at sea level, par with the P39Q. It had no major speed advantages against comptemporary Vvs aircraft. Even the 1942 Yak9 did 320 at sea level, on par with the 1942 P39D.

[humble]

Originally posted by Krusty
The info on that page might be wrong. For the "1400hp" engine, it states:

"2 X PE V-1710-85 Allison"

2 of them? It must be confused with the P38.

It also states a 32mm cannon. It was 37mm. I think we have to discard that horsepower rating due to those two flaws. Note that even with such a super high rating, its top speed is still listed at 385mph or so, a little higher than the norm (+10mph) but that its rate of climb to 13,500 feet is 5 minutes (2700fpm). The hp might be wrong, but the performance itself seems to be near milspec.

It lists the Lavochkin speed at sea level, but not the P39 speed at sea level. So just going by top speed alone might be mis-leading, but the 1943 -FN surpasses the P39Q at 18,700 feet or so, about 5k higher than the p39. I'm not sure how that breaks down, speed-wise. In the AH speed chart it does about 360 at sea level. Using the speed chart in my previous post (fixed, btw) we see that the 39D did a bit over 320MPH at sea level. The Q seems to be about 20mph faster, so let's say it's 340mph at sea level. That's still slower than the LA5FN. Even the 1942 LA5 comes out to about 334mph at sea level, par with the P39Q. It had no major speed advantages against comptemporary Vvs aircraft. Even the 1942 Yak9 did 320 at sea level, on par with the 1942 P39D.

38 was never in russian service, i'd guess it was a translation goof but I dont know for sure. The AH la-5 is the may 1944 one. Obviously the numbers they have are incomplete as well. The P-39 is the only one with any real specs or production notes. I'd guess thats due to the importance they place on the bird. Reading all the various combat cmparisions on the site i'd guess they found the speed and horsepower numbers in the archives and plugged them in. If you read the russian history on the p-39 they did major overhauls on them (especially engine) to get them to where they wanted them. i'd guess the standard russian rating on the P-40Q was 1420 hp. Which would be in line with the various performance reports i've read.