# Yakovlev Yak-3 v. Bell P-63 Kingcobra



## ShVAK (Aug 29, 2012)

If given the choice, which would've been your preferred mount in the low to medium altitude combat over the Eastern Front circa late '44? 

Let's consider the specs: 

*Yakovlev Yak-3*







General characteristics

Crew: 1
Length: 8.5 m (27 ft 10 in)
Wingspan: 9.2 m (30 ft 2 in)
Height: 2.39 m (7 ft 11 in)
Wing area: 14.85 m² (159.8 ft²)
Empty weight: 2,105 kg (4,640 lb)
Loaded weight: 2,692 kg (5,864 lb)
Powerplant: 1 × Klimov VK-105PF-2 V-12 liquid-cooled piston engine, 970 kW (1,300 hp)

Performance

Maximum speed: 655 km/h (407 mph)
Range: 650 km (405 miles)
Service ceiling: 10,700 m (35,000 ft)
Rate of climb: 18.5 m/s (3,645 ft/min)
Wing loading: 181 kg/m² (36.7 lb/ft²)
Power/mass: 0.36 kW/kg (0.22 hp/lb)

Armament

Guns:
1 × 20 mm ShVAK cannon,
2 × 12.7 mm Berezin UBS machine guns

*Bell P-63A Kingcobra*






General characteristics

Crew: 1
Length: 32 ft 8 in (10.0 m)
Wingspan: 38 ft 4 in (11.7 m)
Height: 12 ft 7 in (3.8 m)
Wing area: 248 sq ft (23 m²)
Empty weight: 6,800 lb (3,100 kg)
Loaded weight: 8,800 lb (4,000 kg)
Max. takeoff weight: 10,700 lb (4,900 kg)
Powerplant: 1 × Allison V-1710-117 liquid-cooled V-12, 1,800 hp (1,340 kW)

Performance

Maximum speed: 410 mph (660 km/h) at 25,000 ft (7,620 m)
Range: 450 mi[35] (725 km)
Ferry range: 2200 mi (3,540 km)
Service ceiling: 43,000 ft (13,100 m)
Rate of climb: 2,500 ft/min (12.7 m/s)
Wing loading: 35.48 lb/sq ft (173.91 kg/m²)
Power/mass: 0.20 hp/lb (0.34 kW/kg)

Armament

Guns:
1× 37 mm M4 cannon firing through the propeller hub
4× 0.50 in (12.7mm) M2 Browning machine guns (two in the nose, two in the wings)
Bombs: 1,500 lb (680 kg) bomb load on wing and fuselage

The Yak-3 had a superior power to weight ratio, better climb and roll rate but the Bell P-63 doesn't seem too far behind. The P-39, which we have far more info on than the -63 in Soviet service, certainly wasn't a slouch in Eastern Front conditions and did have its share of aces. Also had much better payload, armor, and armament than most marks of Yak. 

Worth noting that Marcel Albert, the second-scoring ace of the Free French who served alongside the Soviets in the Normandie fighter group thought very highly of the Yak-3--even comparing it favorably to the Spit and P-51D.


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## davebender (Aug 29, 2012)

What is the internal fuel capacity of these relatively small aircraft?


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## ShVAK (Aug 29, 2012)

Can't find data on either unfortunately.


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## eagledad (Aug 29, 2012)

Hello

The Yak 3 had two 170 liter tanks in the wings (total of 74.8 gallons). The P-63 had two tanks in the wings each holding 63 to 66 gallons each for a total of a 126 to 132 gallons.

Eagledad

Data from America's 100,000 and Yakovlev Aircraft


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## Rogi (Aug 29, 2012)

I'd go with the Yak-3 its variants have been used well beyond WW2 while the kingcobra hadn't. I'm sure the North Koreans used Yak 3s, Not sure if its been confirmed anywhere but I'm 30% sure the Yak-3 had been used in Vietnam (if not I may have confused a North Korean bird for a NV one :S ) 

Proven track record, but at the point in time of the war had I had the choice, I'd of gone with what most pilots were flying at the time, Yak-3 or P-39 most likely, if I had the choice and wasn't ordered to fly something else


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## GregP (Aug 30, 2012)

The numbers are quite wrong. The Bell P-63 could climb between 4,400 and 5,000 feet per minute in some models, even the P-63A (4,600 fpm). It could climb 2,500 fpm on normal power of less than 35 inches of MAP, and routinely climbed at 58+ inches of MAP. Look up the P-63 perormance charts! The "charts" are from the Mike Wiliams collection, dated 5 June 1944. The "E" model started out with the lowest rate of climb at 4,400 fpm, but overtook the rest at about 17,500 feet and outclimbed the rest all the way to 40,000 feet. Weights were 8,200 - 8,500 pounds.

The top speed was anywhere from 425 ("A") - 445 ("E") mph, depending on model. I partitularly like the ones powered by the Allsion G-6 engine with aux supercharger. There were no "dogtooth" squiggles in the speed versus altitude chart.

The P-63 handily outperformed the P-51D for most variables and certainly hit harder when the cannon was working.

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## ShVAK (Aug 30, 2012)

I'd like to see those numbers in full if you have 'em. Wasn't aware that the -63 performed so well at high altitude. 

The P-63 was definitely proof that there was both greater potential and longevity in the Bell design than the USAAF originally thought. I don't think it was well suited to the ETO (at least not outside the Eastern Front) due to lack of range but could've definitely been used to effect in interceptor (it was better in horizontal maneuvers than late-war marks of Bf 109 and Fw 190A) and close air support roles. Too bad the M-4/T9 cannon was never very reliable as an airborne weapon.


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## Juha (Aug 30, 2012)

Rogi said:


> I'd go with the Yak-3 its variants have been used well beyond WW2 while the kingcobra hadn't.



Hello
in fact VVS still used P-63s at least in late 1950.

Juha

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## eWildcat (Aug 30, 2012)

The Armée de l'Air (French Air Force) used its P-63s till 1951 too, and they flew combat missions in South-East Asia.


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## michaelmaltby (Aug 30, 2012)

"... The P-63 was definitely proof that there was both *greater potential and longevity* in the Bell design than the USAAF originally thought. "

Absolutely ..... 

MM


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## CobberKane (Aug 30, 2012)

The design of the P63 apparently had a lot of input from the Soviets, who were always going to be the main customers I suppose. I read somewhere that it was suppied to the USSR on the condition that it not be used in the ETO, but the Soviets happily ignored the injunction - or is that another myth?
Interesting that the Kingcobra retained the 37mm cannon when the P-400 with a 20mm was prefered by many USAAF pilots. The Soviets must have liked it. I also read that by the time of the P63 there was a disintigrating belt for the ammo that gretly improved reliability. Still, you would want to be a pretty good shot to hit a jimking target with that big, slow cannon - but then one hit would have done the job, I guess.


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## spicmart (Aug 30, 2012)

The great climbing performance of the P-63 was also acknowleged by some Luftwaffe pilots, it being capable of outperforming even the Fw 190D-9 in that regard. Source is Axel Urbanke's "First in combat with the Dora-9".


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## Thorlifter (Aug 30, 2012)

If the numbers supplied by Greg for the P-63 are accurate vs if the numbers supplied shVAK for the Yak-3 are accurate, IMHO I think it's a no brainer. I'd go with the P-63.


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## Milosh (Aug 30, 2012)

There was only 1 P-63D and 13 P-63Es built. Might as well call them fantasy a/c.

Bell P-63 Kingcobra 

Specification of the Bell P-63C Kingcobra

Power plant: One Allison V-1710-117 engine with a war emergency rating of 1500 hp at sea level and 1800 hp with water injection. Performance: maximum speed 410 mph at 25,000 feet. An altitude of 25,000 feet could be reached in 8.6 minutes (avg 2907f/m). Service ceiling was 38,600 feet. Weights: 6800 pounds empty, 8800 pounds gross, and 10,700 pounds maximum takeoff.


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## FLYBOYJ (Aug 30, 2012)

Rogi said:


> I'm 30% sure the Yak-3 had been used in Vietnam (if not I may have confused a North Korean bird for a NV one :S )


Not true


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## davebender (Aug 30, 2012)

> Yak 3 total of 74.8 gallons.
> P-63 total of a 126 to 132 gallons.



Yak 3 would be useless unless the fight takes place above your airfield. You might not even complete the dogfight before running out of fuel. How could someone introduce a 1944 fighter aircraft with such a small fuel tank?


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## GregP (Aug 30, 2012)

Hi ShVAK,

Try P-63 Performance Tests

The charts are quite interesting. Also, we just finished overhauling an Allison for a P-63 in San Marcos, Texas (CAF) and it has rather sparkling performance. So does the one at the Palm Springs Air Museum which usually flies in out airshow at the Planes of Fame.

We are now in receipt of two Allisons, one of which will be overhauled for yet another P-63 being restored to flight status in Georgia (U.S.A.). Seems like the P-63's are slowly returning to the air.


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## davebender (Aug 30, 2012)

I don't doubt it. However reports like this leave me feeling somewhat uneasy concerning both the P-39 and P-63. Did Bell ever get the spin recovery problem fixed?
Bell P-63 Kingcobra - Wikipedia, the free encyclopedia


> In February 1944, the Soviet government sent a highly experienced test pilot, Andrey G. Kochetkov, and an aviation engineer, Fyodor P. Suprun, to the Bell factories to participate in the development of the first production variant, the P-63A. Initially ignored by Bell engineers, Kochetkov's expert testing of the machine's spin characteristics (which led to airframe buckling) eventually led to a significant Soviet role in the development. After flat spin recovery proved impossible, and upon Kochetkov's making a final recommendation that pilots should bail out upon entering such a spin, he received a commendation from the Irving Parachute Company. The Kingcobra’s maximum aft CG was moved forward to facilitate recovery from spins


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## FLYBOYJ (Aug 30, 2012)

davebender said:


> Yak 3 would be useless unless the fight takes place above your airfield. You might not even complete the dogfight before running out of fuel. How could someone introduce a 1944 fighter aircraft with such a small fuel tank?


 It was short legged with a range of about 400 miles, but it was far from "suicide." The Spitfire MkI carried 85 gallons imp (102 US).


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## Shortround6 (Aug 30, 2012)

It is what happens when you try to design a high performance fighter with a 1200-1300hp engine. You can't have everything so they sacrificed range for speed, climb and turn. Weight of armament was on the low side too. Excellent performance for what they had to work with but "TANSTAAFL".


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## davebender (Aug 30, 2012)

I've heard that story before and it had an unhappy ending.


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## FLYBOYJ (Aug 30, 2012)

davebender said:


> I've heard that story before and it had an unhappy ending.


Funny but not even close to comparison. As stated, the Yak-3 was short legged but it by no means was "suicide." Look at the fuel consuption of the aircraft - if you were able to fly at full power for one hour you had 45 minutes duration, plenty of time for a sortie within a 100 mile raduis of your home base. It served its purpose well and was one of the better fighters of WW2.


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## ShVAK (Aug 30, 2012)

That is interesting Greg, thanks for that!


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## ShVAK (Aug 30, 2012)

Shortround6 said:


> It is what happens when you try to design a high performance fighter with a 1200-1300hp engine. You can't have everything so they sacrificed range for speed, climb and turn. Weight of armament was on the low side too. Excellent performance for what they had to work with but "TANSTAAFL".



Indeed. 

The Yak-3's armament is the biggest problem for me. A couple 12.7mm's and a ShVAK would've been excellent for a lightweight fighter released in '41 but definitely on the weak side by '44. Apparently the later -3P had three 20mm Berevin but that saw little service before Germany folded.


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## tyrodtom (Aug 30, 2012)

ShVAK said:


> Indeed.
> 
> The Yak-3's armament is the biggest problem for me. A couple 12.7mm's and a ShVAK would've been excellent for a lightweight fighter released in '41 but definitely on the weak side by '44. Apparently the later -3P had three 20mm Berevin but that saw little service before Germany folded.



Two .50 cals and a 20mm may not sound like much firepower, until you consider their rate of fire. The Beresin had a 900-1050rpm rof, the ShVAK had a 800 rpm rate of fire. 

When you put those together you get a total rof not too much less than the combined rate of fire of the P-38's slower firing 4 .50 cals and 1 HS 20mm cannon.


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## Milosh (Aug 30, 2012)

davebender said:


> Yak 3 would be useless unless the fight takes place above your airfield. You might not even complete the dogfight before running out of fuel. How could someone introduce a 1944 fighter aircraft with such a small fuel tank?



The Germans produced the Bf109K-4 in the last 7-8 months of the war in Europe and it sure didn't have sparkling range.

The Soviets weren't looking for a long range a/c. They wanted an a/c for combat over and just beyond the front lines.


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## davebender (Aug 30, 2012)

By late 1944 the Luftwaffe were operating defensively over their own airfields. Me-109K with its low production cost, outstanding rate of climb and heavy firepower was was well suited for that mission. If the Yak-3 had been available during 1941 or 1942 it could have served in a similiar role for Russia. However by 1944 the VVS was normally on the offensive and that requires endurance, which means a decent size internal fuel capacity.


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## Milosh (Aug 30, 2012)

davebender said:


> By late 1944 the Luftwaffe were operating defensively over their own airfields. Me-109K with its low production cost, outstanding rate of climb and heavy firepower was was well suited for that mission. If the Yak-3 had been available during 1941 or 1942 it could have served in a similiar role for Russia. However by 1944 the VVS was normally on the offensive and that requires endurance, which means a decent size internal fuel capacity.



No it doesn't as the Soviets were only concerned with the Front. Soviet fighter bases were located close to the Front.

And, if German fighters carried more fuel they could have made more than one pass at the bombers since they burned so much fuel on their climbed to altitude.


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## Shortround6 (Aug 31, 2012)

tyrodtom said:


> Two .50 cals and a 20mm may not sound like much firepower, until you consider their rate of fire. The Beresin had a 900-1050rpm rof, the ShVAK had a 800 rpm rate of fire.


 True, in part. 



tyrodtom said:


> When you put those together you get a total rof not too much less than the combined rate of fire of the P-38's slower firing 4 .50 cals and 1 HS 20mm cannon.



The Beresin was a lot closer to 800rpm when synchronized Which doesn't put it that far ahead of the P-38s 50 cal guns on a one for one basis. 

ShVAK fired shells weighing about 97 grams so on a weight per second basis it just equaled the Hispano.


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## davebender (Aug 31, 2012)

That's what drop tanks are for. Internal fuel is for aerial combat and (hopefully) the flight home.


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## CobberKane (Aug 31, 2012)

Shortround6 said:


> True, in part.
> 
> 
> 
> ...



So if we use the USN,s rough guide of one 20mm being equal to three .50s, the Yak 3 had about 83 percent of the fire power of a P 51D, whithout allowing any advantage for the soviet machine guns slightly higher ROF and the fact that all the guns were centrally mounted. In practical terms there probably wasn't a lot in it.
The Yak 3 was facing the same enemy as the P51 and like the Mustang it's armament was fine for the job at had - dealing with single and twin engine fighters.


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## Tante Ju (Aug 31, 2012)

davebender said:


> How could someone introduce a 1944 fighter aircraft with such a small fuel tank?



Its operational mission was to achieve air superiority over the frontline, protect their own Shturmowik when operating but a few dozen kilometer behind the frontline, and/or prevent Luftwaffe Jabo and Schlachtflieger from doing the same.

I don't really get why everybody gets judged by the USAAF's doctrine like if it would have been the end-of-it-all. The Russians wanted a fighter with just that range, nobody forced it on them. They choose their own aerial doctrine and employed it very effective. And from their POV for example judged the P-47 with all that fuel etc. little more than another possible Shturmovik.


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## ShVAK (Aug 31, 2012)

Tante Ju said:


> I don't really get why everybody gets judged by the USAAF's doctrine like if it would have been the end-of-it-all. The Russians wanted a fighter with just that range, nobody forced it on them. They choose their own aerial doctrine and employed it very effective. And from their POV for example judged the P-47 with all that fuel etc. little more than another possible Shturmovik.



And if they needed good fighters with longer range than the Yak-3 it's not like they weren't available. Yak-9DD had a maximum range of 1,420 miles, Pe-3bis was around 900 miles.


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## Shortround6 (Aug 31, 2012)

In part everybody gets judged by USAAF doctrine late war because most everybody is looking for the "best fighter" , Not best fighter with 400 liters of fuel or under or best fighter with a 1300hp engine in 1944 or some other limit. 
The Yak-3 was very, very good it what it did. BUT the Russians did not stop production of the Yak-9D (170 gallons fuel?) or the Yak-9DD (220 gallons?) did they? 

Russians _wanted_ more fuel capacity and range from their fighters but the failure to get a higher powered replacement for the Klimov M-105 and the lack of development in most war time Ash-82 engines forced the Russians to restrict weight ( fuel and weapons) in order to improve performance. Something that is quite understandable given their position but such a compromise does limit the planes potential compared to higher powered planes that were not forced to comprise so much. The Russians were working on the M-106 and M-107 engines before the Germans invaded. The Russians knew what they wanted and what their goals were, they were also practical enough to know when these wants and goals were out of reach and lowered their expectations/goals to come up with valid combat aircraft with the resources they had available.


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## davebender (Aug 31, 2012)

What does the USAAF have to do with this discussion?

More then one Me-109 ran out of fuel when operating on the Russian front and that aircraft type carried more fuel then the Yak-3.


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## michaelmaltby (Sep 2, 2012)

Pinball P-63's ......

Tails Through Time: The Bell RP-63 Pinball

This would have been fun flying .... 

MM


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## Tante Ju (Sep 3, 2012)

Shortround6 said:


> In part everybody gets judged by USAAF doctrine late war because most everybody is looking for the "best fighter" , Not best fighter with 400 liters of fuel or under or best fighter with a 1300hp engine in 1944 or some other limit.



What use you see for a Yak 3 with 10-hour endurance _over frontline _and much reduced combat capability tell me? Shturmoviks cant go far anyway. Shturmoviks do not need to go far any way. 



> The Yak-3 was very, very good it what it did. BUT the Russians did not stop production of the Yak-9D (170 gallons fuel?) or the Yak-9DD (220 gallons?) did they?



Special small run aircraft for special circumstance. BTW, what does this tell you to your theory that you need large aircraft to achieve all that tankage..?  



> Russians _wanted_ more fuel capacity and range from their fighters



Simply no... I have never heard of such doctrine. Please enlighten me if you have.



> but the failure to get a higher powered replacement for the Klimov M-105 and the lack of development in most war time Ash-82 engines forced the Russians to restrict weight ( fuel and weapons) in order to improve performance.



No, again. Read Yakovlev, to understand his design principles. He even considered Bf 109 too heavy... 



> Something that is quite understandable given their position but such a compromise does limit the planes potential compared to higher powered planes that were not forced to comprise so much.



If compromise you mean Soviet La 7 and Yak 3 running circles around a so called uncompromised higher powered planes... like P-anything, then its good compromise. Unfortunate high power did not come free and meant that very high engine and fuel weight seriously restricts aircraft ability to fight other aircraft.

Yak 3 shows you do not need high power, but good airframe to achieve same. See also American Muscle cars to a European sports car like Ferrari or Porsche.. the American way always seem to be "go big", like if "big" has a quality on its own.



> The Russians were working on the M-106 and M-107 engines before the Germans invaded. The Russians knew what they wanted and what their goals were, they were also practical enough to know when these wants and goals were out of reach and lowered their expectations/goals to come up with valid combat aircraft with the resources they had available.



What were Russian goals before German invasion..? All Soviet fighters were light weight, Yak 1 was immidiate precedessor of Yak 3, and Soviet (French) engines were not really worse than anyone elses in 1941. I fail to see that such doctrine of lightweight fronline fighters was somehow forced onto Soviet by invasion. They had the same doctrine and fighters before and after the invasion.


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## Shortround6 (Sep 3, 2012)

Tante Ju said:


> What use you see for a Yak 3 with 10-hour endurance _over frontline _and much reduced combat capability tell me? Shturmoviks cant go far anyway. Shturmoviks do not need to go far any way.


I don't see any use for it but that is a specialized role isn't it? Yak-3 was very very good at it, not so good at other things. 




Tante Ju said:


> Special small run aircraft for special circumstance. BTW, what does this tell you to your theory that you need large aircraft to achieve all that tankage..?



And they needed these special runs why? Because their standard fighters could not do the job. 

It also tells me my theory is correct. What was the performance of the Yak-9D and DD? 
The YAk-9D carried less than half the weight of armament of the P-51D and that includes about 1/2 the firing time. It was slower and had a much lower service and combat ceiling.
Compared to the Yak-3 the Yak-9D was down one 12.7mm MG, was slower, had 5000ft less ceiling, climbed a lot slower. 
You can load a small plane with fuel, it just doesn't perform very well. 



Tante Ju said:


> Simply no... I have never heard of such doctrine. Please enlighten me if you have.



Aside from everybody wanting more of everything from their fighters, there was supposed to have been a meeting between Stalin and 3 designers, early in the war, in which Stalin "requested" more range for all the fighters. Two designers said they could while the third explained why his fighter could not accommodate more fuel, after several back and forths it was left that teh other two would would increse the range of their fighters while the 3rd designer would "think on it" and turning down Stalin was not usually a good move. 

Aside from "doctrine" the Russian designers often increased the fuel capacity of their fighters when the opportunity presented itself. Or provided their fighters with drop tanks. 




Tante Ju said:


> If compromise you mean Soviet La 7 and Yak 3 running circles around a so called uncompromised higher powered planes... like P-anything, then its good compromise. Unfortunate high power did not come free and meant that very high engine and fuel weight seriously restricts aircraft ability to fight other aircraft.



Running circles around them???  

Turning a tighter circle at low altitudes yes, out running them, no. The Russian planes might have a problem with climb to, especially if trying to fight at over 12-15,000ft. 



Tante Ju said:


> Yak 3 shows you do not need high power, but good airframe to achieve same. See also American Muscle cars to a European sports car like Ferrari or Porsche.. the American way always seem to be "go big", like if "big" has a quality on its own.



The Yak-3 was very, very good at what it did ( I am repeating myself) but it had some serious limitations and range was only one of them. Some had to do with the engine.

The car analogy is a bad one. The American cars were not designed for the same job/duty or under the same restrictions as some European sport cars. Try putting 5-6 people in a 1960s Porsche. The Americans also had no tax on engine size unlike some European countries. American engines would usually go longer before requiring "tune-ups". True they didn't handle as well. The American cars could not beat the European cars at what the Europeans were best at but the Europeans could not beat the Americans at what they were best at. Try driving a 1960s Ferrari from Texas to California in the Summer? 





Tante Ju said:


> What were Russian goals before German invasion..? All Soviet fighters were light weight, Yak 1 was immidiate precedessor of Yak 3, and Soviet (French) engines were not really worse than anyone elses in 1941. I fail to see that such doctrine of lightweight fronline fighters was somehow forced onto Soviet by invasion. They had the same doctrine and fighters before and after the invasion.



And the choice of Russian engines _before the Invasion_?
A copy of an old Wright Cyclone. Large in diameter and 1100hp at best? 
A copy of the Gnome-Rhone 14K 14 cylinder radial. also under 1100hp and it stayed that way.
The M-105 series and no, by 1941 they were second class. The French engines were second class in 1940. They were first class ( as good as anybody else's) back in 1938-39 but time does not stand still. 
The AM-35 series. The most powerful but also the heaviest by far. It tops the list at 1350hp and is the best (only?) choice for a fighter that needs to fight at 20,000ft and above. 

With 1100hp engines you have to build light weight fighters if you want performance. Clever streamlining can get you speed ( as proven by the Allison powered Mustangs) but for climb you need light weight. 
I would also point out that due to the difference in timing of the German invasion of Russia the P-40E was a closer contemporary to the Yak-1 than than the P-40C and for all their good points they do point out what happens when you shove 1100-1200hp engines into 8,000lb planes. 

The Russians played a constant game of balancing performance against engine power as shown by the juggling of armament in some of their fighters. Guns are taken out to improve performance and then, as engine power is improved, the guns are put back in or as lighter weight guns are developed, more fire power is installed for the same weight.


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## davparlr (Sep 3, 2012)

Tante Ju said:


> If compromise you mean Soviet La 7 and Yak 3 running circles around a so called uncompromised higher powered planes... like P-anything, then its good compromise. Unfortunate high power did not come free and meant that very high engine and fuel weight seriously restricts aircraft ability to fight other aircraft.



Western fighters were often faster and higher flying, both of which are components of energy. Energy management is a critical need in combat and provides more options to the higher energy aircraft. The P-51B at fighter weight pulling 67" boost was generally faster and equal in climb at altitudes up to 15k and clearly superior above 15k and do this after flying 600 miles. Turning and acceleration is important, but not as important as superior energy. The post May, '44, P-51 could easily out perform the Yak in speed and climb over the envelope. Later engined Yaks could perform quite well relative to the later P-51s at low altitude but their engines were problematic. 



> Yak 3 shows you do not need high power, but good airframe to achieve same.


Depends on whether you want to defend over your own airspace and over the immediate battlefield or project tactical air power deep behind enemy lines.



> See also American Muscle cars to a European sports car like Ferrari or Porsche.. the American way always seem to be "go big", like if "big" has a quality on its own.


Depends on what you want to do. A 1964 Pontiac GTO will go 0-60mph in 7.7 seconds and will carry a family. A 1966 Porsche 911S will go 0-60 in 8 seconds and will not carry a family. The Ferrari is a different story.


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## CobberKane (Sep 4, 2012)

The USAAF captured a Yak 9D during the Korean war and tested it against a P 51D. Their conclusion was that the P 51D was superior in every aspect except horizontal manouverability


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## bobbysocks (Sep 5, 2012)

Tante Ju said:


> See also American Muscle cars to a European sports car like Ferrari or Porsche.. the American way always seem to be "go big", like if "big" has a quality on its own.



BIG does have a quality all its own in this aspect ( cars )...it was luxury. it reflected "the good life" after the war and the prosperous years after. you had room for your wife, kids dog, and aunt harriet and not be crowded. was it extravagant...probably.. but that doesnt make it wrong. its what the people wanted as a symbol of personal success in life...the american dream. some car manufacturers also made small efficent cars...like the chevy corvair. most of the cars made by rambler...especially the nash, were along the lines of european cars...not the sports cars, but family auto, but these were less popular and didnt sell as well. so the correlation between euro and us cars doesnt fit in this picture except that it was built to please and serve a purpose/role.



Tante Ju said:


> All Soviet fighters were light weight.... I fail to see that such doctrine of lightweight fronline fighters was somehow forced onto Soviet by invasion. They had the same doctrine and fighters before and after the invasion.



soviet ac sacrificed survivability for performance. they seemed to have had the same mindset as the japanese who also didnt armor their fighter ac too much either. problem was russia had more men to replace lost pilots with and the japs didnt. russia was able to flood the skies with ac while japan saw theirs dwindle. i cant remember which bio i read of the LW pilot. he remarked that they would shoot down 20 vvs ac and the next day there would be 80 more of them in the air. if you would armor a yak ( or a zero ) to give the pilot the same survivabilty rate as a western ac....they would have not preformed nearly as well and very welll could have been out classed by existing ac. had the eastern war been fought at high alt like the western war...it would have been interesting to see what the VVS would have fielded.


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## ShVAK (Sep 5, 2012)

bobbysocks said:


> had the eastern war been fought at high alt like the western war...it would have been interesting to see what the VVS would have fielded.



Probably developments of the MiG-3, with better armament and more power. High altitude was the only thing it was good for.


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## Shortround6 (Sep 5, 2012)

The Russians had a sever and chronic engine problem. It was probably made worse by the lack of high performance number fuel. The Russians were lagging behind Britain, the US and Germany in the development of high powered aircraft engines. They had plenty of ideas but lacked the ability to turn them into reliable high powered engines. I don't know if was lubrication oil, bearing materials, rare elements for alloys, heat treating technique or combinations of these and more but the Russians were usually a step or two behind when it came to _production engines._
This meant certain things had to be sacrificed in order to get adequate to good performance. Russian aircraft were actually fairly well protected and the Russians had adopted some very good performing guns that were very light in relation to their power which helped offset their poor performing engines. 
I am sorry but M-105P fitted to the prototype Yak and Lagg fighters in 1940 offered 1100hp for take off at 6500ft and at 1050hp at 13,120ft. Unfortunately this is as close to western engines as the series got until the end of the war. The Merlin had been making 1030hp over 3,000ft higher for over two years and the early Allison could make 1040hp at 14,300ft. 
The M-105PF got to 1210hp for take-off and and 1260hp at 2,625ft and 1180hp at 8,860ft. First flight in a YAK-1 in June of 1941. Allison is already in production of teh -39 with 1150hp for take-off and 1150hp at 11,800ft. British have had the Merlin XX in production for a year. By 1943 the Russians have advanced to the M-105PF-2 which offers 1244hp for take-off, 1300hp (1290?) at 2625ft and more importantly 1240hp at 13,210ft. unfortunately it comes at a cost of 30% less time between overhauls. Allison is offering engines with 1200hp for take off and 1150hp at 14,500-15,000ft. not including turbo models. R-R had the 60 series Merlin in production, early Griffon single stage and starting two stage Griffons. There is a M-105PF-3 and M-(or VK) 106 and 107 engines but the first offers scant improvement and latter 2 offer bad reliability and are in and out of production like a revolving door. The 107 finally makes it about the end of the war.


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## tomo pauk (Sep 7, 2012)

The Klimov aero engines were just one 'line' of what Soviets have had. The 2 speed AM-39 was good for 1500 HP from circa 2 up to almost 6 km (ie. up to 19000 ft), while the M-71F (18 cyl radial) was making 2200 HP at take off.


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## Shortround6 (Sep 7, 2012)

Yep and the AM-39 (developed from the AM-35) was a 44.66 liter V-12 ( the displacement of the DB 603) that weighed several hundred more pounds than the DB 603, it was never used in a production aircraft.
The M-71F????

From Wiki so take as you will. 
"Development began at the beginning of 1939 and it was bench tested that August, but did not pass its State acceptance tests until the autumn of 1942."
Granted the German Imvasion may have messed things up a bit. 
"Despite this it was flight-tested in a Polikarpov I-185 prototype fighter in March–April 1942. A boosted version, the M-71F, was built in small numbers. It was flown in the prototypes of the single-engined Su-6 and the twin-engined Su-8 ground-attack aircraft in 1943–44 as well as the La-7 fighter in 1944."

"Evaluations of the M-71 were generally favorable, but no production capacity was available to use for a brand-new engine during the war"

Oookay, but the TU-4 (B-29 copy) used the M-73 radial engine post war. 







And you had the M-72 in between. Was the M-71 really ready for use?

Edit> I believe the M-70, M-71 and M-72 all used the same cylinder dimensions?


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## tomo pauk (Sep 7, 2012)

Shortround6 said:


> Yep and the AM-39 (developed from the AM-35) was a 44.66 liter V-12 ( the displacement of the DB 603) that weighed several hundred more pounds than the DB 603, it was never used in a production aircraft.



If we are to believe Wiki, it's 2380 lbs vs. 2030 lbs for the AM-39 - not such big a difference. That it was never used in production aircraft has nothing to do with engine's qualities - Soviets wanted the low level Mikulin for their Sturmoviks far more.



> The M-71F????



Indeed, the 'forced' version of the M-71 (2200 HP for TO vs 2000). Bolded in the excerpt:



> From Wiki so take as you will.
> "Development began at the beginning of 1939 and it was bench tested that August, but did not pass its State acceptance tests until the autumn of 1942."
> Granted the German Imvasion may have messed things up a bit.
> "Despite this it was flight-tested in a Polikarpov I-185 prototype fighter in March–April 1942. *A boosted version, the M-71F*, was built in small numbers. It was flown in the prototypes of the single-engined Su-6 and the twin-engined Su-8 ground-attack aircraft in 1943–44 as well as the La-7 fighter in 1944."
> ...



So the Soviets have had what it takes, but were out of factories. Again, the engine was just fine. 



> Was the M-71 really ready for use?



Far readier than R-3350, BMW 801, or Sabre were when introduced.



> Edit> I believe the M-70, M-71 and M-72 all used the same cylinder dimensions?



Beats me 

-added: 
this might be some fine reading:
Google Translate


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## Shortround6 (Sep 7, 2012)

The Russians, at times, were more than willing to order engines into production before they had passed official acceptance tests. Sometimes this speed the process up and sometimes it was the engines equivalent of the Blackburn Botha, Hundreds of engines that nobody wants to see in an aircraft. 

The point with the AM-39 is that is lower in power and heavier than a DB 603 and not much different in timing. The earlier AM-35 was a fair achievement at the time and the swirl throttle was certainly interesting and shows the Russians could be inventive and innovative. But 830 kg for a 1350hp engine was just too much. Using a really big basic engine may be simpler than using two stage engines or turbos but it still means a heavy engine installation. The Russians seem to have had a fair amount of trouble with their "follow up" engines, How much of an excuse the "lack of production facilities" is I don't know. I can believe it in 1941/42. It is even believable in 1943, it starts to become suspicious in 1944. 

Like the 18 cylinder radial. One design bureau worked for (on and off) for 7-8 years on it. from wiki:

"The progenitor for the ASh-73 was the M-70. It was tested in late 1938 and was a failure because of cracks in the master connecting rod and the geared centrifugal supercharger's impeller. The exhaust valves also burnt through. The M-71 of 1939 was the successor to the M-70 and it too was not a success. It used some components from the M-62 engine, but its development was slowed by the German attack on the Soviet Union in 1941. It passed its State acceptance tests in the autumn of 1942, but was not placed into production as there was not any production capacity available, although it was tested on a number of different prototypes during the war. The M-72 of early 1945 was a boosted version of the M-71 and was superseded by the ASh-73 before production could get underway"

If the engine is "FINE" why design two more versions of it? Why wait until 1947 to get into production? 

I love this sentence in Wiki on the VK-106 engine "Although reliable and easily installed in M-105-powered aircraft, VK-106 did not enter production because its cooling problems were not solved." 

Reliable yet cooling problems were not solved???? it's either one or the other. BTW at least several hundred VK-106 engines were built. Maybe not "production" by Russian standards but either factory space wasn't that tight or they were desperate for better performing engines. 

Try this from Wiki on the VK-107. 

" Although the engine could have been ready for production as early as 1942, Soviet factories lacked the capacity to produce a brand new design."

and then several sentences later, ". VK-107A was put into production in 1944 and was used on Yak-9U fighters. The engine was not well liked by either pilots or mechanics -- it had a life expectancy of only 25 hours and war emergency power was almost never used for fear of decreasing this even more."

Now they have had 1 1/2 to 2 years to work on it, the Germans are retreating (being forced back, your choice) and at this point 1650hp for take off and 1450hp at 12,500ft is the best that they can do from a 35liter 765kg engine with one of the shortest life expectancy's since the First World War? The desperate need to produce every engine possible should be easing up.
I wonder what the 1942 version would have been like? 

VK-107s were used postwar and may have been used in Korea. 

Not to pick on the Russians too much and to show that "ready for production" may not turn out all that well, we all know the Wright R-3350 was just an 18 Cylinder version of the R-2600 and that it took a number years to get the R-3350 to run even somewhat satisfactorily, Some old B-29 crews may argue with that.


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## tomo pauk (Sep 9, 2012)

FWIW, the Klimov (and many other) engines do need a well researched book, that would draw it's informations from state archives. Wiki articles on techincal stuff are really messy, especially when we real English language version that deals with ex-USSR technicalities.
In the book about the fighters (by Gordon Khazanov), the M-105 follow ups (106, 107, 108 ) are many times claimed as unreliable not really acceptable for the combat use. You can note that I ( a renown expert on everything and anything  )did not claimed othervise  

As for the AM-39 and M-71 - same thing, we need a well researched book. How much of priority was given to those? Were they regarded as necessary worthwhile in the time their mass production was to be started? Were the Soviets better to have a bird in the hand (2000 HP) or a pigeon on the roof (2200 HP)? The article, link provided at above post, covers some issues about the soviet engines, but that should be regarded as a primer, not something definitive?


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## Shortround6 (Sep 9, 2012)

Unfortunately most books that mention soviet engines in any detail not only disagree with each other but with themselves depending on page and paragraph. 

The P-185 fighter From wiki: "However, flight testing was interrupted by the need to replace the engine between 17 December 1942 and 26 January 1943. The new engine failed the next day and the aircraft crashed on 27 January. Flight tests were ordered to be continued with the original prototypes to validate the range figures, but the first prototype crashed on 5 April, killing the pilot as he attempted a dead-stick landing"

This was about the 4th forced landing/crash caused by the M-71 engine and this is 1 1/2 years after the engine was first flown. Granted things were disrupted by the German invasion but it was this last crash that ended production plans for the P-185 and the M-71 engine, not a lack of production space. 

There is a lot "iffy" information. I would grant that the M-82 had higher priority for production than the M-71 but then the M-82 actually worked. The Russians were between a rock and hard place. They needed higher performing engines but they also needed engines that worked. Had a higher powered engine been available that had the same reliability as the lower powered engine I have little doubt the Russians would have switched over one factory. At least in any but the most desperate of times. This story about no factory space until mid 1944 or later has a certain smell about it considering the number of prototypes they were fooling around with, both engines and aircraft. The M-82 and the M-70/73 series are from the same design bureau. A bit like Wright and the R-2600 and the R-3350. (more than a bit as the Russian engines were based off the Wright Cyclone). 

Going back to the M-105 series. At some point the Russians built 150 M-106s in 3 months ( see the AEHS articular for how long it took an American factory to reach it's 150th engine) a number of YAK -1s were fitted with these engines but little or no flying was done before the engines were pulled and replaced by M-105s.


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