P-39 n-0 vs yak 9

[GrauGeist]

I understand your point, Marcel - however, in a sim, it will not compensate for the P-39/P-400 flaws.
The sims I've run ages ago, did not replicate the dangerous flat spin or the shift in CoG as fuel/ammunition was expended. Even the Mudpond profiles in CFS3 were unable to provide an actual replication (although the performance profile otherwise was close).

The Yak-9 (mid, later variants) should be closer to the P-51D/K in profile and comparison.

It would be hard to nail down the P-39's performance directly compared to a Soviet type, but if it was, it would be closer to a LaGG-3 than a YaK-9.

 

[Marcel]

I understand your point, Marcel - however, in a sim, it will not compensate for the P-39/P-400 flaws.
The sims I've run ages ago, did not replicate the dangerous flat spin or the shift in CoG as fuel/ammunition was expended. Even the Mudpond profiles in CFS3 were unable to provide an actual replication (although the performance profile otherwise was close).

The Yak-9 (mid, later variants) should be closer to the P-51D/K in profile and comparison.

It would be hard to nail down the P-39's performance directly compared to a Soviet type, but if it was, it would be closer to a LaGG-3 than a YaK-9.

Yeah I agree. I think the answer here is this that the sim is totally inaccurate if the Yak9 and the P39 have similar performance. In real life, the Yak9 has been the better performer in general.
But back on the sim subject. I believe these games serve a purpose. They sometimes spark interest into the real history behind it. For instance Pops ended up on this forum asking questions, didn't he? And at least, he knows the Yak9 and P39 existed. He probably would not have known that if not for War Thunder.

 

[FLYBOYJ]

Sorry guys, I find it a bit cheap to start bitching on flight sims. Pops here likes to play flight sims and there is nothing wrong with that in my opinion. I used to play IL2 and MS Flightsim all the time back in the day. And when I was allowed to fly a real Cessna 172 for the first time, my instructor said he could notice I played flight sims as I was much kinder on the yoke compared to most other first timers and I wasn't compensating every little movement the aircraft made just to keep it straight and level. So apparently the sim taught me something even though it's not fully realistic.

And I think the question is perfectly valid. He noticed that the P39 and the Yak9 are of similar performance in the game so he's wondering how accurate this projection is in the real world. Sounds reasonable to me, he shows that he does understand these sims are not accurate and is curious what the real life situation could have been.

But I'll keep an eye on the thread because it's another P39 thread again and the last dozen or so about that subject went south very quickly. Pray it doesn't happen here

Agree to a point Marcel but IMO our young friend at times has a hard time listening and accepting some real life facts about aircraft and when making comparisons to what he's seeing in these games.

Putting it bluntly - "Listen more and talk less"

 

[DerAdlerIstGelandet]

Sorry guys, I find it a bit cheap to start bitching on flight sims. Pops here likes to play flight sims and there is nothing wrong with that in my opinion. I used to play IL2 and MS Flightsim all the time back in the day. And when I was allowed to fly a real Cessna 172 for the first time, my instructor said he could notice I played flight sims as I was much kinder on the yoke compared to most other first timers and I wasn't compensating every little movement the aircraft made just to keep it straight and level. So apparently the sim taught me something even though it's not fully realistic.

And I think the question is perfectly valid. He noticed that the P39 and the Yak9 are of similar performance in the game so he's wondering how accurate this projection is in the real world. Sounds reasonable to me, he shows that he does understand these sims are not accurate and is curious what the real life situation could have been.

But I'll keep an eye on the thread because it's another P39 thread again and the last dozen or so about that subject went south very quickly. Pray it doesn't happen here

Marcel, there is nothing wrong with playing flight sims. They are fun. One cannot use them to base the actual flight characteristics of a plane though. People just get worked up when gamers try and do that.

 

[Juha3]

the original yak 9

OK, sorry I read your 1st message, not the title of the thread. IMHO an ok comparison, Yak-9 production began in Oct. 1942 and the first P-39Ns were delivered in Nov 1942. Yak-9 production run was short, only 500 were made in 3 vast factories, the same number than the P-39N(-0) production. Yak-9T production began in March 1943. In March 3 were built, in April 75 and soon 100 per month, the first 100 of Yak-9Ds were assembled during the spring 1943.

Yak-9, max speed 520 km/h at SL, 599 km/h at 4,300 m.
Climb to 5,000 m 5.1 min
Service ceiling: 11,100 m
Turn time (360 deg at 1,000 m) 16-17 secs (left, right)
Operational range: 660 km
T/o run: 305 m
Landing roll: 450 m
Armament: 1x20 mm + 1x12,7 mm.

You probably have P-39N-0 figures, but according to Soviet tests the turn time for P-39N-1 was 19 sec.

Ps. Another Soviet source gives the turning time of Yak-9 as 17-18 sec and a 3rd 17 sec. Not very surprising, different a/c handled somewhat differently and in Soviet mixed construction plane variations were bigger than in Western "all"-metal planes and different pilots tended to achieve a slightly different times.

 

[Marcel]

Marcel, there is nothing wrong with playing flight sims. They are fun. One cannot use them to base the actual flight characteristics of a plane though. People just get worked up when gamers try and do that.

Clear. I didn't interpret it that way in this case, though but it sure happens a lot.

 

[fubar57]

This is nice. Now everyone get nekkid and sing Kumbaya.

 

[CORSNING]

OK then, the real world:
Production: P-39N: 500, P-39N-1: 900, P-39N-5: 695 & Yak-9: 459 aircraft produced.
First Deliveries: P-39N: Nov.1942 (U.S.), Late 1943 (U.S.S.R.) & Yak-9: Dec.1942.
Performance:
P-39N & (Yak-9 Series I)
Altitude: Speed / Climb.
Meters: MPH / FPM
S.L......344 / 3980 (325 / 3299)
1km...362 / 4145 (338 / 3415)
2km...381 / 4220 (351 / 3278)
3km...398 / 3940 (352 / 3400)
4km...394 / 3460 (368 / 3030)
5km...388 / 3060 (371 / 2532)
6km...382 / 2685 (365 / 2044)
7km...376 / 2230 (357 / 1515)
8km...367 / 1745 (344 / 1056)
Maximums: 398.5mph/9,700m. & 4360fpm /2,225m. (373mph/4,340m. & 3445fpm/1,185m.)
Combat Ceilings (1,000fpm): 9,700m. (8,120m.)
Operational Ceilings (500fpm): 10,835m. (9,210m.)
Service Ceilings (100fpm): 11,735m. (10,080m.)
Turn Times: 19.0sec/3,311kg. - 7,301lb. (16L-17Rsec./2,825kg. - 6,229lb.)/1,000m.
Engines: Allison V-1710-85: 1,420hp., (Klimov M-105PF: 1,243hp. [1,260ps])
Wing Area: 213.22 sq. ft., (184.6 sq. ft.)
Wing Loadings: 34.15 lb./sq. ft., (33.74 lb./sq. ft.)
Power Loadings: 5.122 lb./hp., (5.011 lb./hp.)
Maximum Roll Rates: P-39D-1: 75 deg./sec. @ 235mph., ( ? )

Those are the numbers, this is part of the rest of the story:
Soviet Airpower in WW2, Yefim Gordon, Page 441 & 442
"...the first 'Cobas (P-400) arrived in December 1941 or January 1942 but it was not until May
that they became operational.
NII VVS sent a special 'task force' to Ivanovo to test the 'Cobras. The test pilots were pleased
by the fighter's handling, performance and excellent view from the cockpit; the tricycle
undercarriage allowed it to taxi at high speed over a snow-covered airfield with virtually no
risk of standing on its nose."
Page 446
" ...maneuvering the Cobra called for a steady hand. At the slightest inaccuracy during a tight
turn, a yo-yo maneuver or at the top of a loop the aircraft would go into a spin - often a flat
spin (from which the P-39 could not recover).
It should be noted that in early 1943 Soviet pilots tested the P-39's spinning characteristics.
Test pilot V. Ye. Golofastov reported that, at CG positions between 25.7 and 29% mean
aerodynamic chord, the aircraft recovered quickly if the spin recovery manoeuvre was executed
immediately after entering a spin. The US standard operational procedure for spin recovery was
rejected as too complicated."

The Yak-9:
Test pilot Fedrovi recorded, "...the new wing delivered a significantly better rate of roll and
aileron response." Compared to the Yak-7A."
" Fedrovi demonstrated the Yak-7DI (Yak-9) could initially outturn any Yak-1." The increase
in maneuverability and roll rate allowed the Yak-9 to outturn the lightened version of the
Yak-1 (1 x 20mm) through the first 360 degrees.
" At the altitudes that almost all of the combat occurred, the Yak-9 could outmaneuver the
Bf 109G." " The improved roll rate allowed the Yak-9 to make use of its superior turning
circle & vertical abilities to full effect against the Fw 190."

PS: Performance figures and information came from the following:
P-39N: Performance test reports for P-39N-1 42-4400.
Yak-9: rkka No. 0211 & 0212 Soviet Graphs and Soviet Combat Aircraft of the 2nd WW by
Yefim Gordon.

 

[Vincenzo]

OK then, the real world:

Performance:
P-39N

Maximums: 4360fpm /7,300m.

this can not be right

 

[Juha3]

this can not be right

Should be ft not m

 

[Vincenzo]

Should be ft not m

yes or 2,300 m

 

[CORSNING]

Nice catch Vincenso. I have corrected my post 88.
Thank you, Jeff

 

[Juha3]

...It would be hard to nail down the P-39's performance directly compared to a Soviet type, but if it was, it would be closer to a LaGG-3 than a YaK-9.

There is always the question of the version, LaGG Series 4 was a dog, Series 66 was a decent fighter. IIRC according to Barkhorn his hardest fight was against a well flown LaGG-3, 15 min inconclusive dogfight. I admit that I have not read anything recent on Barkhorn.. One naval fighter regiment fighting against Finns during their strategic offensive during the summer 1944 was still equipped with LaGG-3 Series 66s, and according to Finnish combat report it was a well trained unit.
And I'm not aware that there was much complains with 16 GIAP when they converted from Yak-1s to P-39s in early 1943 (It got P-39 L-1s, K-1s and D-2s). Yak-9 was better than Yak-1, I admit. And in late 44 Pokryshkin said "Thanks but no thanks" for the conversion of 9 GIAD from P-39Ns and Qs to La-7s. And 9 GIAD was an elite formation which was moved around to be used to give support to the big strategic offensives. I read once that on of these was delayed a couple of days because there was problems to get enough 100 octane LL-fuel to airbases used by the 9 GIAD.

 

[pbehn]

The Yak-9 and P-39 were on the same side, it is completely sensible for the Russians to develop the Yak with strengths that the P-39 didnt have, it gives your opponent more problems to solve. If they were the same in every respect someone has done something wrong. The Spitfire Mk XIV and Tempest had strengths and weaknesses depending on altitude, it gave the LW two problems to solve.

 

[Dimlee]

The Yak-9 was used in Korea. The P-39 was notable in its absence. I think that speaks to Soviet opinions on the two planes.

That is true, but I don't think it speaks about the Soviet opinions. One was a lend leased aircraft with no supplies after 1945, another was from the established production series.

 

[Dimlee]

The sims I've run ages ago, did not replicate the dangerous flat spin or the shift in CoG as fuel/ammunition was expended.

Il2 air sim replicated spin characteristics of P-39 since it first appeared in the game. Sim pilots complained a lot.
CoG shift was more complicated, I was not sure the developers did it right at that time. Not sure about the latest mods.

 

[pbehn]

That is true, but I don't think it speaks about the Soviet opinions. One was a lend leased aircraft with no supplies after 1945, another was from the established production series.

I was just posting about the principle in 1942 when they first came into service and with reference to the thread post. Russia was receiving but not developing the P-39, you would only try to make the Yak match the P-39 if you were fighting against it, not with it in the same force.

 

[Thumpalumpacus]

That is true, but I don't think it speaks about the Soviet opinions. One was a lend leased aircraft with no supplies after 1945, another was from the established production series.

Yeah, I've already been corrected on that score.

 

[Marcel]

This is nice. Now everyone get nekkid and sing Kumbaya.

Didn't know you were in those kind of things fubar. But if you really want to do that, we could probably organise something for you I guess

 

[Peter Gunn]

am i too young to get it?

Clearly you weren't paying attention to the P-39 penalties in another thread.