# Yak-1/7/9 vs Bf109G2



## Knegel (May 25, 2010)

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 (May 25, 2010)

Knegel said:


> 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.
> 
> ...



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 (May 25, 2010)

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 (May 25, 2010)

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 (May 25, 2010)

Timppa said:


> 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 (May 25, 2010)

vanir said:


> 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.
> ...



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 (May 25, 2010)

claidemore said:


> 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.
> 
> ...



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 (May 25, 2010)

riacrato said:


> 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 (May 25, 2010)

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 (May 25, 2010)

Vincenzo said:


> 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 (May 25, 2010)

Hello,



Knegel said:


> 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.
> ...


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 (May 25, 2010)

VG-33 said:


> 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 (May 25, 2010)

Hi Vincenzo,



Vincenzo said:


> 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. 



Vincenzo said:


> 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.



Vincenzo said:


> 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 (May 25, 2010)

Hi VG-33,



VG-33 said:


> 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.



VG-33 said:


> 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.



VG-33 said:


> 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
> ...


----------



## Vincenzo (May 25, 2010)

Knegel said:


> Hi Vincenzo,
> 
> 
> Do yu have any datasheets to back this theory up??
> ...



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 (May 25, 2010)

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 (May 25, 2010)

i don't speak russian but i think overboost


----------



## VG-33 (May 26, 2010)

Vincenzo said:


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



But, as far as you know from *what* source?


----------



## Knegel (May 26, 2010)

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


----------



## VG-33 (May 26, 2010)

Knegel said:


> 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


----------



## Vincenzo (May 26, 2010)

ever from george of allaboutwarfare


----------



## Knegel (May 26, 2010)

Hi,



VG-33 said:


> 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...



If the PF engine had no time limitation, i wonder why they didnt introduce a combat or WEP power setting, like so many other engines had??
For sure the pilots would have been happy to have 100 PS more, specialy between early 1942 and late 1943, when the 109F4, thr early 109G and the 190A did rule the sky. 

Do you have any data sheets to backup the "no time limit"??



VG-33 said:


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



The question is not how to translate it, the question is where to find a clarification of the russian naming of the different power settings. What does "nominal rating" stands for?? I have some ideas, but i still only can guess.



VG-33 said:


> 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.


Maybe it dont had take off rating, cause they already did overboost the engine?? I did read that Kilmov himself was against the PF engine, cause he thought the reliability would suffer to much(i think the statistics show he was right). Of course, nevertheless they had to increase the power cause they needed it. Still it would be strange if there wasnt any limitation.



VG-33 said:


> 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.


Higher rpm or higher boost, both lead to a hotter engine, while a higher boost very fast can cause detonations, specialy with not constand fuel quality. 



VG-33 said:


> 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...


I should have written "The next successfully evolution...." 




VG-33 said:


> 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



Ok, so the 105 engine power values are correct, there is no other boost, like someone above suggested.

If there was realy no official limitation, regarding the time of usage, of the "nominal rating", i guess its rather cause they realy needed the power to get closer to the german plane performences, than the engine could stand the power in a good way.
With the aircombat in most cases close to the frontline, with a leader who didnt care much about own(human) losses and with endless material sources, a engine limitation wasnt as important as for the germans and west allieds.
The engine limitations for the allied planes operating only over england(V1 and FW190 hunting) also was different to the long range escort limitations.

Greetings,

Knegel








Greetings,

Knegel


----------



## VG-33 (May 26, 2010)

Vincenzo said:


> ever from george of allaboutwarfare



I know, it'a type mismatch from Samoletostroenie book. All other sources are quoting 2700 rpm for the nominal rating







Well, it doesn't matter, the main question where is your...


> the speed for yak was in forsage so for around 5' minutes and the speed


...taken from? 

Bye


----------



## vanir (May 26, 2010)

from the flight manual for the Yak-3 (PF-2 motor)



> Опробовать мотор на номинальной мощности. При нормальной работе мотора
> показания приборов на номинальной мощности должны быть следующие:
> - обороты 2600-2700 в минуту;
> - наддув 1100+30 мм.рт.ст.;
> ...



2600-2700 is the nominal (military) engine speed

there is no "forszhage" or special boost but such a term is more associative with the german sondernotleistung or overboost (a modification to the boost regulator using a mechanical override), not "war emergency power" which is dealt with by simple pilot control and calibration of the throttle linkages.

Any pilot can overspeed the motor, richen the mixture and use a variety of other little tricks to get what is commonly referred to as "war emergency power" for short field or heavy loaded operation.
Just as in the same way with the Allison there was a manufacturer limitation of 3000rpm, pilots in the field often oversped the engine for higher pressure calibration (as much as 72"Hg by some accounts), using 3200rpm which post war became the maximum limitation published (source: All Engines Data website).

Russian sources I'll have to browse for a while to try to find again, have listed the maximum safe speed of the M-105 motors at 2800-3000rpm in combat (a "war emergency" setting if you will). I can't remember if this was anecdotal I apolegise, but it was authoritive which is why I remember it so acutely. To be honest I was looking up Soviet airframe production at some obscure Russian aircraft museum site and got sidetracked into reading about M-105P/PF development in 1942.

I am aware the Klimov was developed from the 12Y Hispano but the site stipulated it had undergone much improvement in the M-105P derivative, so wasn't quite as speed restricted as the Hispano (which doesn't much like going faster than 2600rpm at all).

But most importantly I'd like to point out that Operational Guidelines published do not necessarily reflect an aero engines capabilities nor even common practise in the field. The P-40 is an excellent example of this, and the conditions under which the Yak was operated is very similar, with varying fuel quality and "learn as you go" doctrine on its service use. Allison Division clearly revised its published operating procedures based on field experience at least twice, once in late 42 and then again about mid 43 increasing emergency maximums from 46"Hg to 52" successively and winding up with some 1580hp out of what was supposed to be an 1150hp motor.


----------



## vanir (May 26, 2010)

> 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.


if this is true I'll happily stand corrected, but I am rather curious as how this works mechanically.


----------



## VG-33 (May 26, 2010)

vanir said:


> if this is true I'll happily stand corrected, but I am rather curious as how this works mechanically.



 only in russian 

Винты обратной схемы (ВИШ-61, АВ-5), у которых уменьшение установочного угла происходит под действием центробежных сил лопастей, а давление масла используется для увеличения шага. Эти винты, как и электромеханические, не имеют противовесов на лопастях. 
ВИШ имеют различный диапазон поворота лопастей: ВИШ-105В (Ла-5) - 30°, ВИШ-61П (Як-1, ЛАГГ-3) - 35°, Curtiss Electric (Р-39, Р-40) - 30°, Hamilton-Standart Hydromatick (Р-51D) - 42° , VDM (Bf-109)-24°. Менее скоростные самолеты имели винты с меньшим диапазоном: винт АВ-5Л-158 (Ил-2) - 20° (от 19 до 39°).
Для полета на максимальной скорости, набора высоты, взлета и т. д., выгодно задавать максимально допустимые обороты, т.к. поддерживая их, двигатель отдает винту полную мощность. Но необходимости в сохранении максимальных оборотов при полете не на полной мощности нет, т.к. двигатель, работая на малой мощности с большими оборотами, имеет большой удельный расход горючего, а винт - пониженный к.п.д., его лопасти работают с очень малым углом атаки. 
Управление шагом осуществляется с помощью регулятора постоянных оборотов (РПО). Для примера его работы возьмём регулятор винта Р-7. Цилиндр винта и регулятор Р-7 соединяются при помощи масляного канала, по которому масло либо подается насосом регулятора в цилиндр винта, либо сливается в картер мотора. Насос регулятора забирает масло из магистрали и повышая его давление, посылает в регулятор. Большую часть времени он работает вхолостую. Управление потоком масла производится золотником регулятора –для автоматического управления его перемещением при изменении оборотов используется центробежный регулятор, который приводится во вращение от вала мотора и реагирует на изменение оборотов: при их изменении нарушается равновесие между силой пружины, стремящейся опустить золотник, и центробежными силами грузиков регулятора, стремящимися его поднять. При некотором числе оборотов они уравновесятся, и золотник займет нейтральное положение. Это и будут обороты, которые РПО поддерживает постоянными. Отклонение от них вызывает перемещение золотника и изменение шага винта, что приведет к восстановлению равновесных оборотов. На ролике РПО устанавливался упор больших оборотов, который останавливал движение рычага в положении, соответствующем максимальному числу оборотов. Возможны и иные конструкции РПО.
Кстати, часто демонстрируемый в кино истошный вой падающего самолета мог быть в реальности - при повреждении маслорадиатора давление масла в системе падало, лопасти винта отклонялись в положение «большой шаг» и набегающий поток воздуха вместе с работающим двигателем раскручивал винт до недопустимых оборотов. То же происходит в режиме раскрутки винта, т.е. нештатном режиме работы РПО, происходящим по различным причинам (замерзание золотников в РПО, длительное пикирование с отрицательной перегрузкой на ВИШ обратной схемы и т.д.). Более подробно на тему винтов изменяемого шага, можно прочитать книге Аронина Г.С.«Работа автоматического винта» М. 1945 .


In fact the R-7 was using motor oil to keep RPM constant inside the propeller main cylinder, by regulating propeller path. That mean increasing or decreasing prop momentum (force of resistance from blades).

But maybe you'll found simplier to read in your own language, since it works as the same principle that elsewere...


----------



## vanir (May 27, 2010)

This is a hydromatic constant speed propeller according the mechanical description (using a web based translator). The oil pressure valve is calibrated to a given max rpm as according to OKB/TsAGI specification at the time (sounds like it works basically like a turbo blow off valve, described as "borrowing neutral" when the max rpm is reached).

You are quite right and the prop limits max rpm to a given calibration, although this can be recalibrated by ground crew in the field (the same way as the blower regulator on American aircraft can be recalibrated in the field but the effect is max-rpm instead of max-manifold pressure). Mechanically speaking at least, from the description.
Another consideration is the lag you get in hydromatic props, they overspeed in throttle on dives and there's a little lag with sudden adjustments (how big depends on torque and compression ratio).

What is fairly likely is again you are quite right and the M-105 series were speed limited to 2600rpm by the prop, but in power on dives they'd tend to lag themselves to 2700rpm because of the hydromatic prop, then settle back down to 2600rpm at maximum engine speed pitch, so they're listed in the pilots handbook as 2600-2700rpm.

Until I can find a current source saying otherwise I'll stand corrected and go with this figure then.

do have to mention it is perfectly possible the given description is in the context of setting the neutrality of the pressure valve manually, by the pitch control, which is equally likely and thus describing how it limits engine speed doesn't necessarily restrict the maximum engine speed if the pilot sets the higher engine speed. At this point, because I've failed to find a current link otherwise I'll concede but there is still no explicit mechanical reason the M-105 series cannot engage a pilot induced war emergency setting.
Engines are mechanical things, and will do what you mechanically tell them to (even if it blows them). By definition a nominal setting can be exceeded for a short period of time wherever the pilot is prepared to risk overheating quickly and associated problems (seal integrity, pinging). A nominal setting is simply international convention for the military power rating, where maximum continuous is the maximum cruise speed (economy cruise is used more often). A lot of engine specifications never list war emergency power, since it is not designed for any use except rare emergency occasions (go around or getting bounced by a dozen enemy fighters).


----------



## vanir (May 27, 2010)

crazy forum tonight, another double post


----------



## VG-33 (May 27, 2010)

vanir said:


> This is a hydromatic constant speed propeller according the mechanical description (using a web based translator). The oil pressure valve is calibrated to a given max rpm as according to OKB/TsAGI specification at the time (sounds like it works basically like a turbo blow off valve, described as "borrowing neutral" when the max rpm is reached).



The pilot selects the quoted RPM, on a lever, there is an equiliber betwenn oil pressure and the spring. The oil input circuitry in a kind of PLL differential phase locks loop.



> You are quite right and the prop limits max rpm to a given calibration, although this can be recalibrated by ground crew in the field (the same way as the blower regulator on American aircraft can be recalibrated in the field but the effect is max-rpm instead of max-manifold pressure). Mechanically speaking at least, from the description.


I'm less sure of that, it should be contained on the working gap/ bandpass. Maybe, can you adjust the regulator from 1200 (?) to 2700 rpm (+50-50 rpm), but maybe not 2800 or 3000, since it's outside the R-7 capabilities. Tt takes the R-43 AFAIC remember one from the same manufacturer.
There is a limit of max adjustement of the pressure blow controller (bronzavia for france), propeller angles (chauviere, ratier), carburettor input (zenith), fuel pump (solex), lubrication circuitry. As in your car. 
You can calibrate some adjustement values with the ground crews for a *serial *plane, nothing more. In April 1942 th, a factory brigade from Moscow leaded by the flight engeener Nikitine transformed 7 *experimental* Yaks 7 from the 236th IAP, for higher boost. But they were highly qualified specialists with factory means and special devices and features, not ground crews with guenine spare parts. Moreover the attempt lead to nothing, in order to keep heat in tolerable values, the RPM (thank you R-7...) had to be limited on 2550-2400 rpm max. So the 10 mph increase was not usable at the end, in that form.

You can't change plane parameters like that, it lead to a lot of consquences and other transformations; bigger radiators, modified carburettors with 1.1 instead of 0.25 mm feeding ducts etc, etc...






> What is fairly likely is again you are quite right and the M-105 series were speed limited to 2600rpm by the prop, but in power on dives they'd tend to lag themselves to 2700rpm because of the hydromatic prop, then settle back down to 2600rpm at maximum engine speed pitch, so they're listed in the pilots handbook as *2600-2700rpm*.



2600-2700 seems to be the max R-7 adjustement gap.

2800-3000 the max tolerated overrun (in diving). Rather the Pe-2 problem.



> Until I can find a current source saying otherwise I'll stand corrected and go with this figure then.
> 
> do have to mention it is perfectly possible the given description is in the context of setting the neutrality of the pressure valve manually, by the pitch control, which is equally likely and thus describing how it limits engine speed doesn't necessarily restrict the maximum engine speed if the pilot sets the higher engine speed. At this point, because I've failed to find a current link otherwise I'll concede but there is still no explicit mechanical reason the M-105 series cannot engage a pilot induced war emergency setting.


It's sure, there were political reasons too. Soviet engeeners were even more mass arrested than red army officiers, during Stalin's terror programm. In that context Klimov choosed lack of power complaints rather than massive engine breakdowns ones. So the M-105 overboost was undertaken under Yakovlev's initiative *and* respunsability, not Klimov's one.




> Engines are mechanical things, and will do what you mechanically tell them to (even if it blows them). By definition a nominal setting can be exceeded for a short period of time wherever the pilot is prepared to risk overheating quickly and associated problems (seal integrity, pinging).


It could, maybe. You need some different (non serial) features for that. 

They were on the Allison, the DaimlerBenz, M-82FN, on Klimov 107, not on the 105PF

I'v got and old Renault 19 with 1360 cm² engine, giving 62 (in fact 65-68 from auto magazine tests) HP to wheels. Some sport models gave 72- 85 -(even 115hp 4 valves version) with the same 1360cm² engine, but with different injectors, carbs, regulation devices and etc, etc...

But i'cant obtain such result with my *serially equipped * car and it's *standard *devices.
No more field pilots, technicians could obtain more from serial Yaks. From some numerous pilot's memeors, as Golodnikov at Airforce.ru, some american 100 LL was sometimes used on Klimovs, that makes gaining the plane from extra 15-20 km/h.
Dont know about modifications it takes on the engine. Little practical use, just fun, cause overheat problem again. And no official allowance for that.

Regards

Here is a R-7 scheme fitted on a La-7. Little differcences with the Klimov fitted one.


----------



## vanir (May 28, 2010)

okay I appreciate what you're saying and thankyou for the interesting discussion thus far, but have more points to make

firstly building stock/super stock racing class engines what I do is take serially produced engines under very tight restrictions and roughly double their base horsepower output. Stock passenger cars are basically detuned for drivability, low maintenance and various roadworthy regulations, where aero engines much more resemble race engines built for hill climbing (big torquers, low rpm, high reliability, relatively low maintenance), make no mistake about the very high performance nature of any aero engine. Comparing them to an auto engine means comparing them to pure race engines, they're designed for that kind of efficiency and have most of the features in common.

That Renault of yours, we'd squeeze 130hp out of it just about tripping over it with a spanner. All the angles and porting are going to be ****, the manifolding crap, the ignition system you may as well toss in the bin, the cam needs a regrind at the very least, toss the pumps, new lines everywhere and that's all just to get operating efficiency back up to something like 90% like an aero or race engine because it's going to be more like about 70% if you're lucky now. This is before we start thinking about changing the operating rpm range and actually trying to get more horsepower out of it, just undoing the **** the manufacturer did to it for general production. If I actually started modifying it (compression, operating range, carburetion), I'd be aiming for 160hp naturally aspirated or 200hp blown (these are conservative figures, but would be expensive which is why few would do it).

Most of these features are already on every aero engine, the Hispano and Klimov already have great head porting (for their time), good piston crowns, nice manifolding, port matching, etc.

The zenith carb, that's a slide valve that runs on vacuum. It'll feed as much fuel as the motor can draw. The only thing to worry about is throat diameter because that's going to affect airspeed through the carb, which needs to be matched towards total horsepower output (cfm).
It doesn't have a jet per se, it has a needle and seat, what you do is change the type of needle depending on how much boost you're going to run and the camshaft grind. Essentially valve timing and maximum boost are what the needle is matched to and that works together with the magnetos to give you a spark advance curve (it affects mixture adjustment through the operating range, tunes it so to speak).

So there's nothing about the jets to worry about if I was going to set a war emergency output on my "stock" Klimov M-105.
As far as throat diameter goes if I'm only thinking about upping the engine speed a couple of hundred rpm it's not going to be an issue so long as I select full rich on the mixture setting and limit WEP to something like 1-2min so I don't starve the intake manifold for long.

The diagram you've got there for the R-7 prop, you see that adjustment regulator labelled number 9? Give that half a turn to a turn anticlockwise and that'll give me my extra 200rpm.


Yet again however I would concede that at least one adjustment needs to be made, to the oil pressure regulator on the R-7 by a field mechanic (ie. me with a screwdriver in my hands), in order to get the Klimov to 2800-3000rpm for a WEP usage, and this is not advised in any operational handbook, just something straight out of my head but mostly to demonstrate that an aero engine is a mechanical object which will do mechanical things when you tell it to. There are no magical restrictions on what it can and can't do, just that some things will make it break if you do them.

Think of aero engines like race engines, they're built basically the same way. Just like on a race engine you can play with regulators, calibration and tuning enough to blow the motor. It doesn't just run out of puff like a domestic passenger car engine, because these are detuned from a high volumetric efficiency for roadworthy and drivability reasons (quietness and compromises), or else for a start cars wouldn't have mufflers. Only recently auto engines have been designed for high volumetric efficiency (roughly speaking 80% compared to 70% in the 1970's, variable cam timing ups this at higher rpm ranges too so a modern Honda passenger engine runs similarly to a mild race engine stock at higher rpm).


Now don't get me wrong, at this point I'm conceding to what you're saying on the M-105 engine speed restriction due to the OKB/TsAGI limitation set on the R-7 prop. I'm only suggesting what I believe I might be able to do myself, with spanner in hand, if I was on an airfield in Russia and got given a Yak to play with. I mean thinking as a pilot I don't even understand how any aero engine could not have a "war emergency" setting, because it's up to me to make the control adjustments to get any aero engine to do what I want it to do, if I want to richen it and overspeed it, I can certainly do that, if I want to overboost it I can have a quiet word to my ground mechanic and ask him to recalibrate the regulator linkage for another half a centimetre of control input. It's not rocket science, engines are really easy.


----------



## claidemore (May 28, 2010)

This is great stuff guys. Keep it up!


----------



## VG-33 (May 28, 2010)

Hello,
Just my other 5 pences (kopeks)



Knegel said:


> Hi,
> 
> 
> 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??


The Yak-7l (laminarny) had a laminar winf profile, no Yak-1,3,9 were so experimented.
The main secret, is that Yak-1 was a 1939 "normal" aerodynamics plane, the 109 a "good" 1935 one, altogether with Polikarpov's I-16, I-17 and Hurricane generation.




> 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.


It depends on what Yak...



> 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.


It's seems rather confuse from your post, than strangewise...
It did not worked like that. With the same PF-1 engine, Yak-7B speed reached *progressivey* from 495/500 km/h in mid 1942 to 535 in late 1943. The mid-statistical value for 1943 being 531 (with +12, -9 km/h sigma gap) km/h at SL. Then, the progress stopped.




> 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.


This increase was due to better quality manufacturing standards, and numerous small aerodynamic improvements. Only by sealing hermetic joints between the engine plates and thiknissing radiator fairing lips, TSAGI gained some 19 km/h for once. From theory, the best tear drop shaped fuselage for the lower Cd, should have 1 to 5/6 lengh/hight rate. It's without wing and interference losses. With them, it's more complicated. So the very thin fuselages like the Me-109 or Me-110 ones, have not systemetically the lowest Cd values for undersonic speeds, unlike popular prejudices say. 

Other way, Timppa is right, the Devil is in the details. For instance the Delta Cx (Cd in english) is 0.0012 for the Me-109 "square shapes" canopy, 0.0007 for the accurate P-39'one, and could have been easily reduced to 0,006 and less only with rounded section*. 

So despite it's *not* integrated in the fuselage, the accurate Airacobra's bubbleon top canopy is much less draggy than the 109's razorback's one. It should have been the opposite, with some little efforts by german manufacturer.



Regards.

* Ostoslavski book "Aerodinamicheski Raschet" for engeneers from TsAGI wind-tunnel results


----------



## Shortround6 (May 28, 2010)

vanir said:


> Any pilot can overspeed the motor, richen the mixture and use a variety of other little tricks to get what is commonly referred to as "war emergency power" for short field or heavy loaded operation.
> Just as in the same way with the Allison there was a manufacturer limitation of 3000rpm, pilots in the field often oversped the engine for higher pressure calibration (as much as 72"Hg by some accounts), using 3200rpm which post war became the maximum limitation published (source: All Engines Data website).



The post war max RPM limitation for the Allison was for the late models which had a 12 counter weight crankshaft which weighed 27lbs more than the older crankshaft. This reduced the bearing loads to the point that the bearing loads at 3200 rpm were lower than the old crank at under 3000rpm and meant that the new engines (or old engines refitted with the new crankshaft) could go the same number of hours to overhaul with the same duty cycles at the higher rpm as the old engines could at the lower RPM limits. 

Richening the mixture isn't likely to increase the power of these aircraft engines much, if any, because most of them were already running excessively rich mixtures at full throttle to begin with. The excess fuel, over and above what was needed for combustion, was being used as an internal coolant. For engines with suck through carbs the fuel both vaporized in the supercharger and lowered the intake charge temperature and the raw fuel absorbed heat in the cylinders and carried out the exhaust. For engines with blow through carbs it mostly did the latter. Too much richening of the mixture could lead to lead fouling of the spark plugs. 


vanir said:


> But most importantly I'd like to point out that Operational Guidelines published do not necessarily reflect an aero engines capabilities nor even common practise in the field. The P-40 is an excellent example of this, and the conditions under which the Yak was operated is very similar, with varying fuel quality and "learn as you go" doctrine on its service use. Allison Division clearly revised its published operating procedures based on field experience at least twice, once in late 42 and then again about mid 43 increasing emergency maximums from 46"Hg to 52" successively and winding up with some 1580hp out of what was supposed to be an 1150hp motor.



Allisons are hard engines to generalize about because there were so many slightly different versions. While there are reports of early model Allisons surviving rather extreme abuse ( with no real record of shortened over haul times), some of the later ones did have modifications to strengthen certain parts. Many Allisons were rated at 1150hp but the altitude at which they were rated for 1150 hp changed. 
Then there is the whole fuel question. A lot of the early work (1940-41)on Allisons was done with US spec 100 octane fuel which had no rich mixture rating. It was a different fuel than British 100 octane spec fuel which was actually 115-125 performance number depending on batch. A Tomahawk in North Africa might very well pull a manifold pressure using British fuel that would destroy an American fueled P-40 in seconds. There was at least one batch of US 100 octane fuel that had a rich performance number of under 100. Once the US and the British standardized their fuels and had 100/130 fuel available many of the older engines were able to use WER settings well above their old ratings. 
For Russian use something that might have some bearing on things might be the temperature. Sucking air that is 20 degrees below zero into the engine and compressing it might allow for more pressure to be used than sucking 110 degree desert air into the engine. Most performance charts and operating instructions are written with a 59 degree "standard" day base line.


----------



## Knegel (May 29, 2010)

VG-33 said:


> Hello,
> Just my other 5 pences (kopeks)
> 
> 
> ...



What 109 got tested in the wind tunnel?

The 109 had one of the smalest front surfaces of all WWII planes, Cd is just a factor that need to get multiplicated with this area. And actually i doubt thats the 109F or G-1 airframe.

That most canophys could have been better in a aerodynamical way is well known, but plating glas is mainly flat, as such must canophys with plating glas had a not that good Cd, but still its just the area of the very tiny canopy.

btw, i still dont saw any WWII tests of the Yak´s, so where does the datas comes from??

oh yes, we also have some 109F-4 datas where the plane make 540km/h sea level and 670km/h at hight and some 109G(with DB605A) calculations, where the plane make 700km/h. 

They stand in the same discrepancy to other 109 tests like some Yak datas also wont fit to each other.

Thas why the source of the datas would be very welcome. 

Would be interesting if this datas are calculated or tested and if they are corrected to standard athmosphair etc. 

To test a plane at -20 degree already will make a good different to + 20 degree.

Same strange actually is the discrepancy between some La7 and La5FN datas, where the same engine and very similar airframe show a different of 40km/h over the full height. 
40km/h, thats like a 109G-2 with and without 250kg bombs. 

The La-5FN airframe must have been absolut rubbish, still this radial powered plane was almost as fast as the 109K with same power and faster than the 2000 PS FW190A (according to the datas) .

Still, also for this La5/7 datas i never saw a test.

When i see the datas of the Yak´s and compare them with the known datas of the P-39, it looks extreme strange that this plane got used at all. 
The better gunsight cant make such a different.

Greetings,

Knegel


----------



## vanir (May 29, 2010)

Shortround6 I had no idea about the crankshaft change, great info thanks. Makes very good sense (especially in agreement with Allison Div documents complaining about pilots overspeeding in the field in mid-42 which always made me wonder what the problem was if they got a higher max engine speed postwar anyway).
Also, good points in total you made there, and I do tend to generalise a little when I'm on a roll.

Is it inappropriate to suggest I kind of just feel "wrong" about thinking I can't step up a basic inline aero engine of a Hispano/Allison/Merlin type setup with some pilot control adjustments, at worst some very minor recalibration under the hood, for a short term, 2-5min extra emergency output. Every mechanical bone in my body says I can do that but I just can't find a reference. Bomber engines for example, say an A-20 or a B-25 never have an emergency rating listed in specifications published but they damn sure had one, a matter of pilot input for rough field and heavy load operation, but dealt with in pilot training rather than model-specific pilot handbooks. Full rich, overboost through the gate, overspeed for 1-2min. The engines really confined about this were the German ones once they started all that aeromechanical business, it added situational awareness but took a little pilot control out of hands, so once calibrated the controls only gave set limitations being all mechanically coordinated with throw weights and springs. Everybody else had much simpler, much more direct pilot-engineer controllability though, until well the 70's actually.
I may very well be wrong about the M-105, happy to concede since I can't find the link that mentioned 2800-3000rpm. And don't laugh, but I recall one of the IL2 arcade/sim handbooks mentions it.


Thinking about what Knegel is talking about, I remember some Soviet vets talking about how they loved the P-39 and it was equipped to Guards squadrons as a kind of reward, one of the main reasons being it had very nice pilot equipment, with very reliable compasses and three radios which was a bit of novelty, like a luxury compared to Soviet models. Pilots were very, very happy to jump into a P-39 because it was so well appointed in the cockpit. Some also raved about using the big gun in aerial combat too, I remember one vet having a big laugh about desintegrating a Messer with it, he waved his arms all around and said it just went poof right in front of him when he hit it once.


----------



## vanir (May 29, 2010)

crazy double post, I swear I hit the post button once.


----------



## Shortround6 (May 29, 2010)

vanir said:


> Is it inappropriate to suggest I kind of just feel "wrong" about thinking I can't step up a basic inline aero engine of a Hispano/Allison/Merlin type setup with some pilot control adjustments, at worst some very minor recalibration under the hood, for a short term, 2-5min extra emergency output. Every mechanical bone in my body says I can do that but I just can't find a reference. Bomber engines for example, say an A-20 or a B-25 never have an emergency rating listed in specifications published but they damn sure had one, a matter of pilot input for rough field and heavy load operation, but dealt with in pilot training rather than model-specific pilot handbooks. Full rich, overboost through the gate, overspeed for 1-2min. The engines really confined about this were the German ones once they started all that aeromechanical business, it added situational awareness but took a little pilot control out of hands, so once calibrated the controls only gave set limitations being all mechanically coordinated with throw weights and springs. Everybody else had much simpler, much more direct pilot-engineer controllability though, until well the 70's actually.
> I may very well be wrong about the M-105, happy to concede since I can't find the link that mentioned 2800-3000rpm. And don't laugh, but I recall one of the IL2 arcade/sim handbooks mentions it.



High performance aircraft engines were very highly stressed engines compared to car engines. While their power per cubic inch or power per liter was low their power per pound (or KG) was high. In fact even the low performance trainer engines were fairly high stressed. Granted a Jaguar XK engine is a bit of a lump but in it's "D" Le mans winning configuration it's power to weight ratio was about the same as some of the British inline 4 cylinder Pre-war engines. Some mid 50s Porsche 4 cam engines had power to weight ratios of about 2 pound per HP. Porsche may not have gotten under 1 pound per HP until the 12 cylinder 912/917 engines of 1970. 3 out of 4 German Pre-war Grand Prix engines didn't make it under 1 pound per HP despite high boost (2 stage superchargers in some cases), exotic fuels and a rather high budget. And I dare say their overhaul life wasn't quite up to aircraft standards.
Unauthorized tinkering with the control boxes on the Napair Sabre engine by well meaning mechanics caused enough problems that it became a court martial offence. 
some engines, like the Allison, would stand up to over boosting rather well, given that detonation did not occur. Other engines didn't stand up so well. 
The Hispano (and it's Russian cousins) were engines in the 36 liter class compared to the 27-28 liter Allison or Merlin, but weighed several hundred pounds less than either. Given it's 18mm longer stroke it's ability to rev high might be a bit suspect. going from 2500rpm to 2700rpm increases the bearing loads by about 16% and at 2700rpm the piston speed is virtually the same as an Allison or Merlin at 3000rpm. 

For the bomber engines you mention (both planes used R-2600s) the Take off rating was often as close to an "Emergency rating" as you were going to get. take-off being a 5 minute rating. Please remember that many if not all western allied engines that had WER settings required that each use be noted in the log book because after a certain number of hours total using WER the engine was pulled for overhaul even if it's total overall hours didn't call for it. And in some cases special maintenance procedures or inspections were required after EACH use. this may be for the engines that used ADI to reach their WER. 

Some of the early Allisons didn't tolerate over revving very well. While they didn't fail immediately, they showed a rather nasty tendency to fail in next few hours of use. Usually one or two flights AFTER the one in which the over revving took place. 

And over revving in a dive with the engine at part throttle didn't hurt the engine as bad as over revving at full throttle. The mean force being transmitted by an early Allison (-33) connecting rod being 3800lb over the length of the stroke at full throttle without over boosting or over revving. The mean force being transmitted by an early Allison (-33) connecting rod is about 3800lbs for the length of the stroke at full throttle without over boosting or over revving. 

edit> you probably could boost any of those engines power out put for 2-5 minutes by some adjustments, but you are playing fast and loose with the engines reliability. Just as with car engines there are going to be "Monday Morning" or "Friday Afternoon" engines in spite of the extra inspections although the 2-4 hour factory run ins should catch most of them. And the pilots manuals are supposed to apply to a fresh engine or one that has 200 or more hours on it.

Do you want to fly in a airplane that has a 200+ hour engine that was not the best of it's production run to begin with that has been "tweaked" by a 19 year old mechanic working under a tarp trying to remember what another mechanic told him over coffee last week??


----------



## vanir (May 29, 2010)

> Unauthorized tinkering with the control boxes on the Napair Sabre engine by well meaning mechanics caused enough problems that it became a court martial offence.


OMG, but then again there's definitely something about a Napier I wouldn't be messing with, at 2300hp out of the box the only question anyway would be why for godsake.



> going from 2500rpm to 2700rpm increases the bearing loads by about 16% and at 2700rpm the piston speed is virtually the same as an Allison or Merlin at 3000rpm.


piston acceleration, throw weight, bottom end, more excellent points (somebody give me modern alloys  ).



> WER settings required that each use be noted in the log book


dammit I forgot about this, you'd think I was never an RAAF pilot cadet (you saying it did jog my memory, we were schooled on this but it was a very long time ago)

again you're making good sense Shortround6, cheers.


----------



## Vincenzo (May 29, 2010)

Knegel said:


> The La-5FN airframe must have been absolut rubbish, still this radial powered plane was almost as fast as the 109K with same power and faster than the 2000 PS FW190A (according to the datas) .



i never see data that show that La-5FN was almost as fast atthe 109K, or i need thet you explain how many it's almost


----------



## Timppa (May 29, 2010)

Knegel said:


> What 109 got tested in the wind tunnel?
> Same strange actually is the discrepancy between some La7 and La5FN datas, where the same engine and very similar airframe show a different of 40km/h over the full height.Knegel



Now I believe you are just trolling, instead of wanting any discussion.


----------



## Knegel (May 30, 2010)

Vincenzo said:


> i never see data that show that La-5FN was almost as fast atthe 109K, or i need thet you explain how many it's almost




Hi, 

for example on this page:
Lavochkin fighters

On this page its listed with 573km/h:
http://www.desertstar.co.uk/warbirds/http___www.btinternet.com_~fulltilt_PerformLa5La7.pdf

There is a other comparison graphic floating around here in this forum(maybe even post), where the La5 FN get shown with 575-580km/h sea level.

All this is pretty close to the 109K4 performence with 1850PS, the La7 show the same or even bettwe performence like the like the K4 with 2000PS (sea level). 

I have no idea what is the real source for the La datas, actually i never saw a real complete test for any russian plane, just datas, without source and without circunstances how the the datas was produced.

And i would realy like to see such datas, or at least the source where the known datas came from.

Greetings,

Knegel


----------



## Knegel (May 30, 2010)

Timppa said:


> Now I believe you are just trolling, instead of wanting any discussion.



You are trolling!!

Since what time its trolling to ask for sources??

Drag datas regarding the 109 are not much worth without to know the model they came from.

Regarding the aerodynamic there was a huge different between 109E, 109F/G(MG17), 109G(MG131), 109G6AS/G10 and 109K4.


----------



## Vincenzo (May 30, 2010)

Knegel said:


> Hi,
> 
> for example on this page:
> Lavochkin fighters
> ...




ok at sea level the max speed of La-5FN it's near of that 109K-4, if the K-4 have not MW. but at 3 km there are around 40 km/h of advantage for K-4.


----------



## Knegel (May 30, 2010)

Vincenzo said:


> ok at sea level the max speed of La-5FN it's near of that 109K-4, if the K-4 have not MW. but at 3 km there are around 40 km/h of advantage for K-4.



Sure the K4 has MW50 used to reach 585km/h sea level, its its the DC engine without. The DC engine with MW50 had 2000PS at sea level. 

At 3km the K4 with MW50 had still around 1800PS(at highspeed), while the La5FN already was good below its power peak and had only around 1650PS. 40km/h more with 150PSmore, thats not a suprise. Oh, actually its only 30km/h and thats a suprise , cause just 30km/h with 150PS more power?? 

The La7 is listed with the same speed like the K4 at 3000m(650km/h), still with 150PS less(if it use the same engine like the La5FN).

I only can repeat myself: I would like to see the original tests, where the datas of the russian planes came from.

All other stuff is guesswork.

Greetings,

Knegel


----------



## Vincenzo (May 30, 2010)

for M-82FN afaik 3 km around 1350 hp, at that altitude La-5FN speed it's ~610 km/h, La-7 can go 630 km/h or also 670 km/h (early o late variants) the speed of K-4 can go from 650km/h to 680 km/h depend of powerplant configuration.


----------



## Knegel (May 30, 2010)

1350ps was the Ash-82F at the 2nd supercharger stage, so at 5400m(static power, without RAM effect)
The Ash-82FN had 1630PS at 1650m static power, due to the Ram effect at highspeed the rated altitude got shifted upward to around 3000m. 
The La5FN speed curve, shown in a russian fighter comparison sheet, display roundabout 620km/h at 3000m, a similar sheet show 650km/h for the la7 at this altiude.
The only known 109K4 DB605DB + MW50 speed curve also show 650km/h at 3000m.
The 109K4 with DB605DC without MW50 was roundabout 5km/h slower, but thats just fluctuation, cause both engines should have the same power output(1850PS sea level, 1900PS at 800m, 1600PS at 6000m, all static power).


----------



## Vincenzo (May 30, 2010)

Knegel said:


> 1350ps was the Ash-82F at the 2nd supercharger stage, so at 5400m(static power, without RAM effect)
> The Ash-82FN had 1630PS at 1650m static power, due to the Ram effect at highspeed the rated altitude got shifted upward to around 3000m.
> The La5FN speed curve, shown in a russian fighter comparison sheet, display roundabout 620km/h at 3000m, a similar sheet show 650km/h for the la7 at this altiude.
> The only known 109K4 DB605DB + MW50 speed curve also show 650km/h at 3000m.
> The 109K4 with DB605DC without MW50 was roundabout 5km/h slower, but thats just fluctuation, cause both engines should have the same power output(1850PS sea level, 1900PS at 800m, 1600PS at 6000m, all static power).



my power was yes static but are right 3km, static, it's the badest of low altitude for M-82 engines, it's the lowest value before to start the 2nd supercharge. i'm no expert but for me it's hard think that 1650 metes statico became 3000 with ram effect.
La-5FN go around 610 km/h to 3, 620 km/h at around 5.5 km. La-7 at 650 km/h it's a intermediate variant neither early or late.
109 k curves Kurfrst - Performance of 8 - 109 K4 and K6 with DB 605 ASCM/DCM
with 605D with MW 680 km/h at 3km
with 605DC/ASC w/o MW 650 km/h at 3 km
with 605DB/ASB with MW 660 km/h at 3 km


----------



## Knegel (May 31, 2010)

This test curves are all made with the "Dünnbrettschraube "(new propeller), the seriel propeller made 10km/h less.
The DB605D test never felt to my Eye´s, although i was on Kurfürsts page many times.

Interesting to see is that the DB engine had a 1000m higher rated altitude with MW50, so somehow the presure must have been smaler, this would explain the discrepancy.

Still the La5FN and La7 different need a claricication, 35-40km/h cant come from some simple cleanups.

Somewhere i did read that there was a Ash82FN and FNU engines, maybe thats the cause?


----------



## Vincenzo (May 31, 2010)

Knegel said:


> This test curves are all made with the "Dünnbrettschraube "(new propeller), the seriel propeller made 10km/h less.
> The DB605D test never felt to my Eye´s, although i was on Kurfürsts page many times.
> 
> Interesting to see is that the DB engine had a 1000m higher rated altitude with MW50, so somehow the presure must have been smaler, this would explain the discrepancy.
> ...



La-5FN and La-7 are not same plane


----------



## VG-33 (Jun 1, 2010)

Hello



> What 109 got tested in the wind tunnel?


The E for sure, probably the F, might be the G. But what does-it change for the 109’s high Cd square-shaped canopy?



> The 109 had one of the smalest front surfaces of all WWII planes, Cd is just a factor that need to get multiplicated with this area.


And one of the highest Cd = 0.036 for in-line engeened planes. From Hoerner studies.



> That most canophys could have been better in a aerodynamical way is well known, but plating glas is mainly flat, as such must canophys with plating glas had a not that good Cd, but still its just the area of the very tiny canopy.


For most canopys I don’t know, at least Yakovlev and Bell teams made their jobs, Masserschmitt’ s one didn’t.
A 0.0007 increase in Cd value, even reported to the fuselage only, not the full airframe (don’t have the time to browse my docs now) is* not a negligible *effect.

Of course, it's just one reason between one hundred (ore one thousand of reasons) that made the Yak faster.




> btw, i still dont saw any WWII tests of the Yak´s, so where does the datas comes from??


Mainly from the NII-VVS, LII-NKAP, sometimes from experimental operative units, TsAGI reaserch center had it’s flying team too.




> They stand in the same discrepancy to other 109 tests like some Yak datas also wont fit to each other


.
You should keep your ideas in order. I previously wrote
_The mid-statistical value for 1943 being 531 (with +12, -9 km/h sigma gap)_
So (+12, -9 km/h ) *is* the *discrepancy*: the fastest serial Yak-7B flew at 544, the slowest ones at 523 km/h at SL
531 is the* mean *value for Yak- 7B planes assembled in the second-half of 1943.

The mean value was 495-500 km/h for the 1942 planes and about 515 for the early 1943 ones.
This is called *improvement*, from TsAGI devices. As I wrote, previously
_Only by sealing hermetic joints between the engine plates and thiknissing radiator fairing lips, TSAGI gained some 19 km/h for once_
BTW, did Messershmitt company tried to reduce drag from radiator fairing leading edge redesign, or were it just a stupid plate wall? Were there attempts to use so called “Meredith” effect?



> Would be interesting if this datas are calculated or tested and if they are corrected to standard athmosphair etc.


Usually in the world of aeronautics, yes!




> Same strange actually is the discrepancy between some La7 and La5FN datas, where the same engine and very similar airframe show a different of 40km/h over the full height.
> 40km/h, thats like a 109G-2 with and without 250kg bombs.


And you know what, all the La-5F, La-5FN, La-7 used in 1944* the same *Shvetsov M-82FN engine…
With mean 613, 634, 662 km/h respectively at rated hight for serial planes.

Of course the were some discrepancy and speed loose, from serial to experimental and “standard” (reference) planes:
620, 648, 680 km/h due to poor manufacturing quality. 

But, the mean speed increase between the tree models is for well-known reasons, since they were obtained by several modifications *on the same * airframe. 50km/h (24 km/h for hermetic sealing, 15 for other reasons) on the SN° 37212282, and on the “Dubbler”. Some sources quoted the heat/pressure (Meredith) optimised effect on the FN model. The SN 37212282 being the transition from La-5F to FN airframe.
35 km/h at least were gained on the SN° 39210206, transitional from the La-5FN to the La-7.

But it’s outside the tread subject




> he La-5FN airframe must have been absolut rubbish, still this radial powered plane was almost as fast as the 109K with same power and faster than the 2000 PS FW190A (according to the datas) .


Difficult to say, without aerodynamical knowledge, what should be rubbish and what not. It takes an experienced graduated engeneer.



> Still, also for this La5/7 datas i never saw a test.


Here for instance, a complaint report with an unsatisfactory La-7, from the NII-VVS

??????????


"See" your later after your “banned” period,

Regards


----------



## Kurfürst (Jun 2, 2010)

VG-33 said:


> And one of the highest Cd = 0.036 for in-line engeened planes. From Hoerner studies.
> 
> Regards



Hoerner's figures are estimates, based on some very rough estimates of speed, thrust and propeller effiency. They are in disagreement with the actual Messerschmitt papers and polars I have, which state a Cd = 0.023 for the 109F/G - that's pretty avarage BTW.

But basically Cd is a meaningless figure, its not even a measure of aerodynamic cleaness. Its always related to wing area, not the entire wetted or frontal area. Basically aircraft with smaller wing area will get higher Cds because of this, since the wing only creates a portion of the drag (say 30-50%), but you compare 100% of the drag to that figure.


----------



## VG-33 (Jun 3, 2010)

Hello



> But basically Cd is a meaningless figure, its not even a measure of aerodynamic cleaness. Its always related to wing area, not the entire wetted or frontal area. Basically aircraft with smaller wing area will get higher Cds because of this, since the wing only creates a portion of the drag (say 30-50%), but you compare 100% of the drag to that figure


.

Basically the drag coefficient *is always *reported to the frontal aera for hydro- aerdynamical science except the aeronautical branch for old peremptary habit reasons. Fortunately there is no low forbidden you to use Cdw, Cdf related to the entire wetted or frontal area, and compare it then to a thin plate. It’s why it’s often done. If you got values for both 109 an Yak planes, you’re welcome.

Sure, the Cd wing ‘s not the panacea, but it’s far from being meaningless too, as well as you don’t compare apples and oranges, Gee-Bees and Friedrichshafen G-III planes.



> Hoerner's figures are estimates, based on some very rough estimates of speed, thrust and propeller effiency. They are in disagreement with the actual Messerschmitt papers and polars I have, which state a Cd = 0.023 for the 109F/G - that's pretty avarage BTW.



Hoerner is fully right from it’s start hypothesis. And i'm not against to have a look at Messerschmitt Polars.

But from Knegel’s figures:



> Sea Level:
> Bf109G-1 525km/h 1310PS
> Yak-1/9 530km/h 1210PS



It takes a 73% propeller output *(0.73)* to obtain a *0,023 Cd *(0,0316 Cd x (êtha)) for the Me-109. But VDM wouldn’t agree with that.


From the RDK 43 TsAGI manual, the output was 0.785 “practical” for the mounted VISh. I take *0.78*.
It makes a *0.0207 Cd *for (0.0266 Cd x (êtha)) for Yak.

Not very impressive, since Yak 1-9 Cd ranges from 0.0255 to 0.0195. It’s pretty close to the Me-109 values.
Personnaly; i don’t see any reason for Knegel to loose sleep for that...

The I-301 (LaGG-1 exp) Cd being more impressive = 0.185 with 0.78 prop output, but 200 -250 kg heavier (more induced drag) and some wing slots extra drag. But it’s nothing compared to the Spitfire and the Mustang.

Regards


----------



## drgondog (Jun 3, 2010)

Kurfürst said:


> Hoerner's figures are estimates, based on some very rough estimates of speed, thrust and propeller effiency. They are in disagreement with the actual Messerschmitt papers and polars I have, which state a Cd = 0.023 for the 109F/G - that's pretty avarage BTW.
> 
> But basically Cd is a meaningless figure, its not even a measure of aerodynamic cleaness. Its always related to wing area, not the entire wetted or frontal area. Basically aircraft with smaller wing area will get higher Cds because of this, since the wing only creates a portion of the drag (say 30-50%), but you compare 100% of the drag to that figure.



The reason these drag discussion get out of hand is that people on these forums don't get simple agreement regarding what they mean relative to various components of drag.

When calculation Parasite Drag in toto there are MANY components, when summed up, relate to all the individual contributors. Many simply look at a zero lift drag contribution of the wing and loudly pronounce "there is your Cd0 - now lets find CL and we are ready to talk aero"

Not so - and the other frequent dialogue is to calculate the Cd at max speed, and then use that value as a constant everafter when discussing for example 'turning characteristics'.

DRAG is Non Linear. If one has a drag bucket plot of Parasite Drag and Induced Drag as a function of velocity it is all there for you FOR LEVEL FLIGHT throughout the flight regime - but the high point Parasite Drag at the high end is a* summation *of Cdo x wing area, Cdf for entire wetted area of the airframe, Cd contribution for an open wheel well, a turret, multiple engine nacelles, antennae, gaps in elevators and ailerons and flaps, trim drag for control surface deflections, etc - ALL go into the Parasite Drag summation, along the entire flight profile and only a few relate specifically to the plan view area of the wing... whereas Induced Drag is entirely related to the Wing plan area..

Once the discussion departs from non accelerated, variable speed, variable altitude and variable bank angles - do Not pull out some mysterious "Cd0" and proudly proclaim that you have the answer to the Holy Grail..You don't.

That would be BS...and entirely in the world of Asymmetrical flight conditions over the wing/body where spanwise flow, different loads and drag on "up vs down' wing, trim drag, etc, etc, etc, etc - which are NOT factored into the standard Drag Polar.


----------



## Timppa (Jun 4, 2010)

Kurfürst said:


> Hoerner's figures are estimates, based on some very rough estimates of speed, thrust and propeller effiency. They are in disagreement with the actual Messerschmitt papers and polars I have, which state a Cd = 0.023 for the 109F/G - that's pretty avarage BTW.



Hi,
can you post the document.


----------



## Kurfürst (Jun 5, 2010)

Great post, DGD! =D>

@Timppa,


----------



## VG-33 (Jun 5, 2010)

Thanks

And are theese sheets related to the F or the G?

The C(alpha) was it for Landung? Was it the freeflow or propeller blowed value?


----------



## Timppa (Jun 5, 2010)

Thanks, Kurfürst.
I am quite puzzled, as where the difference comes from. Hoerner's subject was apparently G-6, the most draggy submodel, but still


----------



## Kurfürst (Jun 5, 2010)

The first one is an F datasheet, the second one is G polar. As for its contents, you already know as much as I do, and I think people better trained in engineering then I am to properly explain the deeper meaning of these docs.


----------



## VG-33 (Jun 6, 2010)

Timppa said:


> Thanks, Kurfürst.
> I am quite puzzled, as where the difference comes from. Hoerner's subject was apparently G-6, the most draggy submodel, but still



Hello Timppa

The Hoerner 1944's 109 G was flying at 380 mph at 22 000 ft, 1200 hp.The chosen prop output was 0.85.

I have made my calculations at SL, 525 km/h, output = (0.73).

The Cx =P. (etha) / (rhô) . V^3 . S

Cx being Cd in french. So it's inversly proportionnal to the density and the cubic speed order. So the 660 km/h flying G1, would have a Cd reduced from (660/610)^3 value. 
( 1.08 ) ^3 = 1.26 
So G-1 Cd (0.36/1.26) =* 0.285*

Not 0.23 but the plane is flying at a higher both fuselage and wing AoA, due to the density and some power loss at altitude.

Horner's report is somewhere on the WWII Aircraft Performance site

As DrGondog said in his repy, the Cd has no vocation to stay constant.

Regards


----------

