Yak-1/7/9 vs Bf109G2

[Knegel]

Hi,

i want to create the EAW flightmodels for some Yak planes, but when i insert the basic values into the flight files, i need to give the Yak planes a incredible low drag value to reach the speeds that i could find.

Was there a special secret in the Yak1 to Yak9 airframe(laminar airfoil or so) or was the engine more powerfull than the datas say??

No matter how long i look to the planes, i cant see where the 109G2 airframe was that much more wose than the Yak airframes.

This are the datas i have so far:

Yak-1b and Yak-9D or T:
M-105PF-1
1210 PS Sea Level
1260 PS @800m
1150 PS @1600m
1180 PS @2800m

The altitudes are for the static power, the rammed power altitudes at Vmax must have been roundabout 500-900m higher, so the critical alt 2nd supercharger stage must have been at around 3700m.

Bf109G-1:
DB605A
1310 PS Sea Level
1400 PS @2100m
1300 PS @3000m
1250 PS @5800m

Also here the altitudes would increase by 500-900m(depending to the altitude and speed.

So here the power/speed comparison:
Sea Level:
Bf109G-1 525km/h 1310PS
Yak-1/9 530km/h 1210PS

1650m(best alt 1st supercharger stage M-105PF-1 at Vmax) :
Bf109G-1 555km/h 1350PS
Yak-1/9 568km/h 1260PS

3700m(best alt 2nd supercharger stage M-105PF-1 at Vmax) :
Bf109G-1 595km/h 1300PS
Yak-1/9 598km/h 1180PS

The above are actually the fastest Bf109G-1 datas i could find but also the fastest Yak datas.

Strangewise other Yak´s(1/7/9) also with M-105PF-1 show "only" 515-520 km/h Sea level and 560-580km/h in around 3800m.

So do anyone have datas, why the Yak airframe had a so low drag or better thrust than the power would make believe??

Since the wingarea was greater than that of the Bf109G and also the fuselage dont seems to be smaler, it would be interesting to get some infos where the Yaks could gain such a advantage.

Greetings,

Knegel

 

[Timppa]

Hi,

i want to create the EAW flightmodels for some Yak planes, but when i insert the basic values into the flight files, i need to give the Yak planes a incredible low drag value to reach the speeds that i could find.

Was there a special secret in the Yak1 to Yak9 airframe(laminar airfoil or so) or was the engine more powerfull than the datas say??

No matter how long i look to the planes, i cant see where the 109G2 airframe was that much more wose than the Yak airframes.

So, what are the Cd0's by your calculations ?
Compare them, eg. with P-51, the ultimate benchmark.
IMO, the Yaks are not particularly stellar, but Bf109 had quite high drag coefficient.
And you cannot judge the drag by "look". The devil is in the details.

 

[vanir]

It's the power rating of Yaks, the given figures are for military at 2600rpm and not maximum at 2800-3000rpm.

This is a frequent issue, you get the same problem with the P-40 series where military ratings not maximum take off are listed in published specifications.
Sometimes the maximum continuous is the published figure. Other times the maximum war emergency power, like with the Merlins.
So in fact a ~1500hp single stage Merlin is the same animal as a ~1200hp Allison with only minor differences. In fact the Allison produces more power, the final cleared maximum emergency rating for the F-series Allisons on standard high grade (100/130) fuel was 1580-1650hp and with the F4R the pressure altitude is up around 12,000ft
but the published figure is the military rating according to initial release OP of 1150-1200hp

I've read similar things about the Klimov PF motors from Russian sites but have found difficulty trying to find them again (it was a few years ago during other research).
Anecdotally, the kinds of things I've read are a complicated tale of Russian aero industries and TsAGI inspectors continually refining manufacture, testing examples, making small adjustments, field modifications.
Particularly considering the published figures for the PF motors are definitely at 2600rpm which is definitely the military rating and not the maximum which is 2800-3000 according to the manufacturer, I would use the same rule of thumb as with the Allison. 1260hp at 800m probably translates to more like 1350hp at 2800rpm but it's difficult to estimate as there are no guidelines for overboost, only that rpm can go higher.

 

[claidemore]

A fully loaded Yak1 b will weigh about 600 lbs less than a loaded 109G1-2.
The Yak airframe is 2 feet shorter than the 109, wingspan is 4 inches greater.
Your data for the Yak seems accurate but the speeds you have listed for the 109 seem a bit low to me and look like figures for a 109G with external ordnance.

Check out this chart:
Kurfrst - Flugleistungen Me 109G - Baureihen

The figures to look at there would be for a G2/R2, which would give the closest performance to a clean G2.

 

[riacrato]

So, what are the Cd0's by your calculations ?
Compare them, eg. with P-51, the ultimate benchmark.
IMO, the Yaks are not particularly stellar, but Bf109 had quite high drag coefficient.
And you cannot judge the drag by "look". The devil is in the details.

Bf 109 drag coefficients will vary a lot between subtypes. Bf 109 F was the best of the early to mid-war 109s, but G-2 is similar except for non-retracting tail wheel (usually) and slightly larger oil cooler. No bumps on wings (not all at least, I'm still unsure how many had the strengthened undercarriage) or cowling (obviously).

The Yaks' tail wheel is also non-retracting but they have air intake integrated in wingroot iirc. But it also has thicker wing profile iirc.

 

[Knegel]

It's the power rating of Yaks, the given figures are for military at 2600rpm and not maximum at 2800-3000rpm.

This is a frequent issue, you get the same problem with the P-40 series where military ratings not maximum take off are listed in published specifications.
Sometimes the maximum continuous is the published figure. Other times the maximum war emergency power, like with the Merlins.
So in fact a ~1500hp single stage Merlin is the same animal as a ~1200hp Allison with only minor differences. In fact the Allison produces more power, the final cleared maximum emergency rating for the F-series Allisons on standard high grade (100/130) fuel was 1580-1650hp and with the F4R the pressure altitude is up around 12,000ft
but the published figure is the military rating according to initial release OP of 1150-1200hp

I've read similar things about the Klimov PF motors from Russian sites but have found difficulty trying to find them again (it was a few years ago during other research).
Anecdotally, the kinds of things I've read are a complicated tale of Russian aero industries and TsAGI inspectors continually refining manufacture, testing examples, making small adjustments, field modifications.
Particularly considering the published figures for the PF motors are definitely at 2600rpm which is definitely the military rating and not the maximum which is 2800-3000 according to the manufacturer, I would use the same rule of thumb as with the Allison. 1260hp at 800m probably translates to more like 1350hp at 2800rpm but it's difficult to estimate as there are no guidelines for overboost, only that rpm can go higher.

Hi,

according to my kilmov datas, the 105-P had combat rating of 1100PS(1st stage, 2000m) and 1050PS(2nd stage, 4000m), the 105-PF-1(1942/43, Yak-1 to Yak-9T) had combat rating of 1260PS(1st stage, 700m) and 1180PS(2nd stage, 2400m), the 105-PF-2(1944) had combat rating of 1310PS(1st stage, 300m) and 1260PS (2nd stage, 2100m).

Rpm for the P and PF-1 is 2700rpm, for the PF-2 i dot have the rpm datas.
The P use 1,24 ata, the PF-1 use 1,42 ata.

The P engine have a service rating of 990PS(1st stage, 2000m) and 945PS(2nd stage, 4000m) with 1,24 ata and 2600 rpm.

I never did read something about a higher rpm than 2700 for the P and PF-1 and only the very late and rare PF-3 had more power again, afaik it didnt count as reliable anymore.

The next evolution of this engine was the M-107A.


Are there any other engine data sheets around, with a higher rpm and power??

Greetings,

Knegel

 

[Knegel]

A fully loaded Yak1 b will weigh about 600 lbs less than a loaded 109G1-2.
The Yak airframe is 2 feet shorter than the 109, wingspan is 4 inches greater.
Your data for the Yak seems accurate but the speeds you have listed for the 109 seem a bit low to me and look like figures for a 109G with external ordnance.

Check out this chart:
Kurfrst - Flugleistungen Me 109G - Baureihen

The figures to look at there would be for a G2/R2, which would give the closest performance to a clean G2.

Yes, the Yak1b is a little lighter, but the Yak-7b and Yak-9 fit rather good with the weight(3030kg for the G2), but anyway, at highspeed in ratehr low level the weight isnt that important anyway.

Look to the heights for the G-1 datas i give, the speeds are not the max speeds, just the speeds in a special altitude. This datas are the best i ever saw for a 109G.

Greetings,

Knegel

 

[Knegel]

Bf 109 drag coefficients will vary a lot between subtypes. Bf 109 F was the best of the early to mid-war 109s, but G-2 is similar except for non-retracting tail wheel (usually) and slightly larger oil cooler. No bumps on wings (not all at least, I'm still unsure how many had the strengthened undercarriage) or cowling (obviously).

The Yaks' tail wheel is also non-retracting but they have air intake integrated in wingroot iirc. But it also has thicker wing profile iirc.

Hi,

early 109G-1/2´s almost could retake the tail wheel, but there wasnt closing doors and the wheel did reach a little over the surface.
Late Yak´s could retake the tail wheel.

Yes, i also thing the early 109G´s, same like the F´s had a rather clean outfit, similar to the Yak´s.
Even if the Yak´s was a little more clean, they still had a 1m² bigger wing area.

Are there no Yak test datas floating through the net??

Thank you all for the reply!

Knegel

 

[Vincenzo]

just few notes
the speed for yak was in forsage so for around 5' minutes and the speed of gustav was in climb&combat so for 30' (the was not a 5' limit in '43)
if i understand right the klimov M-105 was not a 2 stage engine but a single stage with 2 speed
the output of DB show in the 1st post are for max power not available in '43 and not same of speed test


edit there are many test this form George of allaboutwarfare forum
Доступен с Построено V H V H V H V H V H Vср Вес м2 л.с. кг/л.с. 100*м2/кг Т 5 км, мин Vy ср на 5 км, м/с Двиг. Зв=0,5 Ряд=0 Броня, кг/100 Боезапас Vбоезап, 5*сек. Топливо, кг Дальность, км
И-26 490 0 572,5 3 3,5 592 4,97 2700 6 13,89 700 1 ШВАК 2 ШКАС
Як-1 0218 02.41 473 0 553 2,95 547 3,4 573 4,86 572,5 5 2832 5,26 1 ШВАК 2 ШКАС
Як-1 0406 02.41 480 0 558 3,1 552 3,5 577,5 4,95 578 5 2858 5,7 700 1 ШВАК 2 ШКАС
Як-1 0511 06.41 490 0 577 3,14 568 3,85 585 5 586,5 5,1 2847 5,7 700 1 ШВАК 2 ШКАС
Як-1 2029 08.41 471 0 546 3,2 560 4,8 5 2951 6,8 305 685 1 ШВАК 2 ШКАС
Як-1 3855 11.41 441 0 519 3,1 533 5,3 3033 5,9 1 ШВАК 2 ШКАС
Як-1 масс. (Степанец) 472 0 569 4,86 2950 5,7 1 ШВАК 2 ШКАС
Як-1 без бомб, ухватов, РС и РО 472 0 542 2,85 534 3,6 563 4,85 562 5 2930 5,9 1 ШВАК 2 ШКАС
Як-1 с РО без РС 460 0 551 4,7 2960 6,05 1 ШВАК 2 ШКАС 6 РС 82
Як-1 с РС 437 0 528 4,5 2995 6,2 1 ШВАК 2 ШКАС 6 РС 82
Як-1 33-60 03.42 10 1 ШВАК
Як-1 08-68 ПФ 529 0 567 1,45 594 3,5 2930 6,4 1 ШВАК 2 ШКАС
Як-1 1569 483 0 559 4,45 2917 7,3 1 ШВАК 2 ШКАС
Як-1 1569 ПФ 510 0 553 1,85 571 3,65 7 5 2917 6,4 1 ШВАК 2 ШКАС
Як-1ПФ 73 СЕРИЯ 07.42 С 04.06.42 НАЧАЛИ УСТАНАВЛИВАТЬ М105ПФ А С №1079 В 07.42 ПОЛНОСТЬЮ НА НЕГО ПЕРЕШЛИ
Як-1 2985 ПФ 09.42 501 0 550 1,85 543 2,5 570 3,8 568 4,2 565 4,6 562 5 2900 1 ШВАК 2 ШКАС
Як-1 5085 ПФ 08.42 523 0 568 2,00 564 2,7 592,5 3,85 590,5 4,2 585 4,7 579 5 6,25
Як-1б 5085 ПФ 517 0 563 1,95 589 3,9 2915 6,06 1 ШВАК 1 БС
Як-1 ПФ 87 серия ПОЯВИЛОСЬ УБИРАЮЩЕЕСЯ ХВОСТ. КОЛЕСО
Як-1 4596 ПФ 09.42 20 526 0 592 3,8 2780 4,7 1 ШВАК
Як-1 2898 ПФ 516 0 569 3,55 2940 5,8 1 ШВАК 2 ШКАС
Як-1б 99 серия 10.42 ПОЯВИЛИСЬ ПОНИЖЕННЫЙ ГАРГРОТ И 1БС ВМЕСТО 2 ШКАС
Як-1б 1699 ПФ 10.42 524 0 584 3,5 2920 5,2 1 ШВАК 1 БС
С 15 НОЯБРЯ 42 НАЧИНАЮТ ВНЕДРЯТЬ УЛУЧШЕНИЯ АЭРОДИНАМИКИ ПО РЕКОМЕНДАЦИЯМ ЦАГИ. ЗАКОНЧИЛИ ВНЕДРЕНИЕ К 110 СЕРИИ
Як-1б 20110 528 0 588 3,75 1 ШВАК 1 БС
Як-1б 03111 530 0 590 3,7 1 ШВАК 1 БС
Як-1б 04111 515 0 553 1,8 548 2,4 580 3,9 2934 5,2 1 ШВАК 1 БС
Як-1б 37126 528 0 597 4,3 2880 6 1 ШВАК 1 БС
Як-1б 07127 03.43 521 0 570 2 564 2,8 591 4,1 2884 5,5 1 ШВАК 1 БС
Як-1б 08136 530 0 598 4,3 2875 1 ШВАК 1 БС
Як-1б 31139 05.43 536 0 582 2,05 578 2,6 608 4,1 2873 5,6 1 ШВАК 1 БС
Як-1б 46139 05.43 539 0 583 2,05 579 2,6 610 4,1 2864 5,7 1 ШВАК 1 БС
Як-1б 23148 08.43 516 0 565 1,95 560 2,6 589 3,95 574 5 2882 6,1 1 ШВАК 1 БС
Як-1б 12150 09.43 528 0 598 3,4 5,4 1 ШВАК 1 БС
Як-1б 13150 09.43 528 0 570 1,9 564 2,7 597 4,25 2895 5,1 1 ШВАК 1 БС
Як-1б 01155 10.43 522 0 592 4,15 2870 5,5 1 ШВАК 1 БС
Як-1б 12163 11.43 522 0 589 4,05 2998 5,8 1 ШВАК 1 БС
Як-1б 12163 11.43 527 0 1 ШВАК 1 БС
Як-1б 36176 02.44 528 0 590 2890 5,2 1 ШВАК 1 БС
Як-1 1943 ср Степанец 531 0 568 1,7 561 2,6 592 4,1 591 4,4 588,5 4,7 584 5 567,44
Як-1 1-19 серий 01.41 451 480 0 558 3,1 552 3,8 577,5 4,95 578 5 535,15 2858 17,15 1039,75 2,75 0,6 5,7 14,62 305 690 1 ШВАК 2 ШКАС
Як-1 20-42 серий 08.41 709 472 0 544 3 538 3,7 564 4,85 563 5 524,18 2950 17,15 1039,75 2,84 0,58 6,5 12,82 305 690 1 ШВАК 2 ШКАС
Як-1 43-65 с. с РО, без РС 11.41 460 0 532 2,85 526 3,55 552 4,7 550 5 513,81 2980 17,15 1039,75 2,87 0,58 6,65 12,53 305 690 1 ШВАК 2 ШКАС 6 РС-82

 

[VG-33]

just few notes
the speed for yak was in forsage so for around 5' minutes and the speed of gustav was in climb&combat so for 30' (the was not a 5' limit in '43)
if i understand right the klimov M-105 was not a 2 stage engine but a single stage with 2 speed
the output of DB show in the 1st post are for max power not available in '43 and not same of speed test

Neither Hispano, Nor Klimov until the VK-107 had a forsage regime, only "nominal" that mean "max continuous power" in correct english. It' by difinition. Some planes were limited in hot weather, mostly for 42'th series wth the early 105PF due to cooling, later improved. Not by engine capabilities.

Regards

 

[VG-33]

Hello,

Hi,

Yes, i also thing the early 109G´s, same like the F´s had a rather clean outfit, similar to the Yak´s.
Even if the Yak´s was a little more clean, they still had a 1m² bigger wing area.

Knegel

But also 0.65 m less in lenght, and different shape, different wing profile...

But. Maybe you'd explain us why are you so upsed by a rather average Cd of the Yak?

The Lavotchkin's LaGG-1 being better.

So the I-301 heavier by 250 kg (2968 kg) was anyway faster
515 km/h at SL at 1020 hp
605 km/h at 4900 m at 1100 hp.

And the Spitfire?, with 6,3 m² wing aera more, was at least as fast as the 109E, with the same power. This is not more impressive?

Regards

 

[Vincenzo]

Neither Hispano, Nor Klimov until the VK-107 had a forsage regime, only "nominal" that mean "max continuous power" in correct english. It' by difinition. Some planes were limited in hot weather, mostly for 42'th series wth the early 105PF due to cooling, later improved. Not by engine capabilities.

Regards

i'm sorry but afaik 2700 rpm was not max continuos for M-105

 

[Knegel]

Hi Vincenzo,

just few notes
the speed for yak was in forsage so for around 5' minutes and the speed of gustav was in climb&combat so for 30' (the was not a 5' limit in '43)

Do yu have any datasheets to back this theory up??
At least for the "P" engine i saw "service rating" additonally to "normal rating", the question is what does this mean, what was the time limitations??
"service rating" could be "climb power" and "normal rating" could be "combat power", or "normal rating" is "comabat/climb" and "service rating" is like "max continius". I guess its the 1st, this would explain the rather bad climb ratios.

if i understand right the klimov M-105 was not a 2 stage engine but a single stage with 2 speed

Since i can see a constand rpm but stable ata, i guess its a 2 stage supercharger, at the end its only important that there are 2 stages of some sort.

the output of DB show in the 1st post are for max power not available in '43 and not same of speed test

Thats combat climb power, 1400 PS in 2100m, available for 30 minutes in climb condition.

Greetings,

Knegel

 

[Knegel]

Hi VG-33,

Neither Hispano, Nor Klimov until the VK-107 had a forsage regime, only "nominal" that mean "max continuous power" in correct english. It' by difinition. Some planes were limited in hot weather, mostly for 42'th series wth the early 105PF due to cooling, later improved. Not by engine capabilities.

Regards

I only can guess that Vincenzo is right, otherwise the rather bad climb performence of the rather light Yaks dont would fit.

But. Maybe you'd explain us why are you so upsed by a rather average Cd of the Yak?

I think i did already explain why iam curious to see the cause for the datas often shown and also why different Yak9 tests show so big discrepancys.

So the I-301 heavier by 250 kg (2968 kg) was anyway faster
515 km/h at SL at 1020 hp
605 km/h at 4900 m at 1100 hp.
[/QUOTE
Most Lagg-3 datas with 105-P engine i saw show 475-500km/h sea level and around 550-575km/h at around 4800m.
The 105-PF powered Lagg-3 datas i saw are extreme strange at sea level, with 530-545km/h, but since the best altiude of the tests i saw was just 3400m, where the Vmax was 580km/h, i only can guess this was the 105-PF-2 engine and the Vmax was tested in some hundret feel altitude. Whilke the weight of this late Lagg-3´s was around 3000kg(light weight Lagg-3), same like many Yak-9´s.

And the Spitfire?, with 6,3 m² wing aera more, was at least as fast as the 109E, with the same power. This is not more impressive?

The Spitfire was known to have a very thin airfoil, as such a rather smal drag, but also lift, for such a big wing. But with same power even the realy draggy 109E airframe was at least as fast, the 109F and even late G was same fast with less power.

The Spitfire V airframe with DB605A made just 485km/h at sea level and that with 2750kg.
The Spitfire only was faster than the 109F/G airframe when it got a better engine with way more power than the DB605A or in very high altitude, where the light wingload turned to be helpfull.

The Yak datas are realy good, nothing wrong with it, but i would like to see a clarification how this can be. From experiences i know that many datas spreaded through books and the net are mixed up badly and often they are just wrong.

I never saw real(original) russian test datas, like i know them from many allied and axis planes(climb curves, speed curves, with clarifications to the test etc).

Is there anything out there??

Greetings,

Knegel

 

[Vincenzo]

Hi Vincenzo,


Do yu have any datasheets to back this theory up??
At least for the "P" engine i saw "service rating" additonally to "normal rating", the question is what does this mean, what was the time limitations??
"service rating" could be "climb power" and "normal rating" could be "combat power", or "normal rating" is "comabat/climb" and "service rating" is like "max continius". I guess its the 1st, this would explain the rather bad climb ratios.


Since i can see a constand rpm but stable ata, i guess its a 2 stage supercharger, at the end its only important that there are 2 stages of some sort.


Thats combat climb power, 1400 PS in 2100m, available for 30 minutes in climb condition.

Greetings,

Knegel

for P full agree afaik the forsage came on with PF

maybe i've read sometimes of 2 speed single stage but the source can wrongs

i just noted that data from datasheet of 109 G-1 was different from data of power curve DB 605A, that are thats you reported.

 

[Knegel]

btw, what does "forsage" stands for??

I guess its some sort of power setting, but is there a exact clarification, with time to use etc??

 

[Vincenzo]

i don't speak russian but i think overboost

 

[VG-33]

i'm sorry but afaik 2700 rpm was not max continuos for M-105

But, as far as you know from what source?

 

[Knegel]

Sources are what iam looking for, but for now noone did offer new sources.

 

[VG-33]

Hi,

according to my kilmov datas, the 105-P had combat rating of 1100PS(1st stage, 2000m) and 1050PS(2nd stage, 4000m), the 105-PF-1(1942/43, Yak-1 to Yak-9T) had combat rating of 1260PS(1st stage, 700m) and 1180PS(2nd stage, 2400m), the 105-PF-2(1944) had combat rating of 1310PS(1st stage, 300m) and 1260PS (2nd stage, 2100m).

I don't know about your data, but soviet data give nominal rating "Номинальный режим" for the 105P and PA, of of 1100PS(1st stage, 2000m) and 1050PS(2nd stage, 4000m), for 2700 rpm at 910 mmHg.
1100 hp at 950 mm for 2600 rpm at SL for T.O. The time the PA was commited in production (1941) this rating was considered as nominal and used without time limits. The RPM loss was due to the climb/ TO configuration with heavy momentum from/to the prop.
I don't know who's the idiot that translated "nominal" to "combat rating" and moreover invented a 5' forcage rew in it.
It's a kind of a new aeronautical urban legend, something like that...

The P engine have a service rating of 990PS(1st stage, 2000m) and 945PS(2nd stage, 4000m) with 1,24 ata and 2600 rpm.

How do you translate "service rating" in russian? Difficult, since it never existed...

The Klimov 105 had no "combat rating", no CP, no MP, no WEP, no X-leistung. The 105PF had no Take Off rating at all.

I never did read something about a higher rpm than 2700 for the P and PF-1 and only the very late and rare PF-3 had more power again, afaik it didnt count as reliable anymore.

It never exists except maybe in test bench, the R-7 constant speed propeller regulator fitted in that plane wouldn't allow you to overturn the engine more than 2600-2700 rpm in level flight. It means: you increase boost, power if you're still at 2600 rpm, it will increase propeller path only - so speed, not RPM...
But some of our forum members seems to be particulary obtuse with that.
And i nevere heard about the PF-3 engine, serially fitted.

The next evolution of this engine was the M-107A.

No, the M-106 SK, very fiew were produced, and soon modified to M-105PF standards.

It had a single speed blower, giving 1350 hp at 2000+ m, at 1175 mm HG, 1250 hp at SL for "nominal rating", and 1360 hp at SL for TO.
No more CP, WEP, MP than usual...

Are there any other engine data sheets around, with a higher rpm and power??

The M-107, due to developpement difficulties had a "Боевой режим" that mean Combat Rating for the first time in Klimov engines history. But it's another story...

VG-33