How good was the soviet air force?

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Achieving the highest levels of performance (i.e. higher boost or RPM) was a very common issue with many if not most fighter types, and cooling was one of the typical problems which came up. As we know, supercharger boost (usually also correlating with RPMs) was gradually increased with various Anglo-American fighters during the course of the war. IIRC the Bf 109F series were initially restricted in boost to ~1,200 hp due to cooling issues. I think that is what they were referring to there. The Soviets also gradually increased boost and RPM for P-40s and P-39s above the settings from the manual, which is something a few of the Soviet pilots referred to, and is also mentioned in some other overview articles on that Lend Lease site. They considered it necessary for achieving adequate performance with these much heavier aircraft, though it required them to take extra care in maintenance or else they would burn out the engines very quickly. IIRC the Germans and Italians had similar problems in North Africa due to the local conditions (i.e. dust and heat). There were similar conditions in parts of the Russian front i.e. Kuban peninsula.

Shortround6 said:
next "quote"
"Thorough wiring and screening increased the radio reception range to 56 miles (90km), a noteworthy achievement for Soviet fighters of the time."
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I think that is similar to the shorter range radios used by Anglo-American aircraft in the Western Desert in 1942 -43.

Shortround6 said:
Comment 3. I don't know if that means reception of radio signals from other aircraft or from ground station or even if they mean other radios could receive the signals of the Yak-1M at that distance.
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I believe that is a transmission distance.


This is one of the points I was trying to make regarding radios upthread. Getting the radios to work properly was a significant challenge due to issues like this through the war, and radio antennas were also something continuously tinkered with. Antenna posts could reduce speed by up to 5-10 mph.


Agreed.
 
Western engines, when over-boosted, usually remained with the same RPM. German engines when over-boosted (usually via MW 50) also remained with the same RPM. It usually took a significant redesign of engine parts to up the RPM, and such engines usually went up in weight.
 

Well I'm not an expert on superchargers or aircraft engines, but in the manuals, and in many of the tests published on ww2aircraft performance, RPM goes up a bit as the boost goes up.

 
SaparotRob said:
Don't keep me in the dark. Who?
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Я мог бы сказать тебе, товарищ, но это было бы раскрытием государственной тайны бегущему псу, имперскому лакею Запада, и тогда мою семью расстреляли бы, мою собаку отправили бы в космическую программу для жестоких испытаний, а я был бы вынужден жить на свекольной диете и целый день слушать никель.
 
From the book "Yakovlev's Piston-Engined Fighters" by Gordon and Khazanov: "The range of two-way radio communication with the ground was improved - it surpassed 50 km (31 miles) at 1,000 m (3,280 ft), but the level of noise still remained very high." The results of control tests in mid-1943. Yes, RSI-6 was significantly better than RSI-3, however the average quality of the Soviet radio equipment was insufficient comparing to others. Every - and this is not an overstatement - interviewed Soviet pilot who fought on Lend-Lease aircraft emphasized the high quality of communications. And the vast majority of those who fought on Soviet planes are highly critical of the quality of communications. Yes, since 1944, the quality of communication was improved. But it was still far inferior to that of the Americans. The copying of the B-29 improved the situation somewhat - it raised the overall level of the Soviet radio industry.
Some more quotes from the same book: "Liberal oil spillage from breathers during flight at maximum speeds, uneven fuel consumption from the port and starboard groups of fuel tanks, insufficient range of radio communication and various defects that hampered the maintenance of the fighters led to the conclusion: the results of the checkout tests were unsatisfactory. " Yak-7B, December, 1942
Feel the difference: "The Yakovlev OKB paid much attention to special equipment: the aircraft was fitted with a gyro horizon, the RPK-1 0 direction finder, an American SCR-274N radio set and oxygen bottles of increased capacity. The new radio equipment ensured reliable two-way communication at a distance of up to 150 km (93 miles) with the aircraft flying at 1,000 m (3;280 ft) and a reception range of 300 km (186 miles) at an altitude of 7,000 m (22,960 ft)." Yak-9DD development, early 1944.
 
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Wild_Bill_Kelso said:
Well I'm not an expert on superchargers or aircraft engines, but in the manuals, and in many of the tests published on ww2aircraft performance, RPM goes up a bit as the boost goes up.

View attachment 755479
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There are some different limits.
Much like you can (or could) damage engines by 'lugging' them ,hat seems to chart to prevent that. The bearing take more of a pounding load with high cylinder pressures at low rpm than they do if the engine is turning faster.

For the Allison engine it was possible to get 1100hp out of the engine with 9.60 gears at sea level at 2000rpm. The engine chart doesn't show the pressure but it seems that it was not good for it
Engine would be good for over 1700hp at 3000rpm.

There may also have been a problem with the automatic engine control. The automatic control may have adjusted the mixture (rich vs lean) depending on the engine rpm limit and the auto lean limit may have been 2300rpm and 31in?

Just from pure mechanics since the supercharger runs at fixed ratio to the crankshaft increasing RPM will increase the Pressure unless the throttle is used to limit the air intake.

but I don't think that chart is actually showing that.
 
Thank you.
I had forgotten to mention the height factor when comparing radio ranges.
I only hinted at two way communication vs one way.
The test I was referring to seems to have been done in Oct 1943 but the book doesn't say which model radio.
Trying to judge performance from snippets of information can lead to wrong conclusions.

The books I have will often list some problems with prototype or trials aircraft but not say if or when they were fixed so you find out that the cooling problem of the Yak-7 and early 9s (?) continued until at least the fall of 1943. But you don't see that in the Yak-7 and Ya-9 sections.

I have to do a lot of reading between the lines on those books and try to figure out what was being said, and what was not being said. Some other countries or companies were pretty good at steering the narrative also
 
Wild_Bill_Kelso said:
Well I'm not an expert on superchargers or aircraft engines, but in the manuals, and in many of the tests published on ww2aircraft performance, RPM goes up a bit as the boost goes up.
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I was talking about over-boosting.
An over-boosted V-1710 or the Merlin will still be running at 3000 rpm; an over-boosted BMW 801 or R-2800-21 or -8W will still be running at 2700 rpm.
 
The amount of heat a P-40 with an Allison engine has to get rid of when over boosted to 66in at 3000rpm (low altitude North Africa) is roughly 50% more than the heat it has to get rid of running at 44in at 3000rpm. The plane is going faster but nowhere near enough faster to get 50% more air though the cooling system.

Something that just occurred to me.
Where was the Test of the Yak-1B done Russian in Oct of 1943?
A lot of Allied planes had trouble with cooling in summer or tropical conditions when climbing, only a few had trouble with level flight but then we don't know how long they running them.
And here again, does trouble mean when running at 15 degrees C or 43 degrees C or where in between.
 
tomo pauk said:
I was talking about over-boosting.
An over-boosted V-1710 or the Merlin will still be running at 3000 rpm; an over-boosted BMW 801 or R-2800-21 or -8W will still be running at 2700 rpm.
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There does seem to be an upper limit on RPM, I'll give you that. But I think the Russians were initially running at lower RPM partly because of trouble they were having maintaining oil purity and with some other maintenance issues they were having in the field, as well as possibly fuel. The original Kittyhawk (P-40D/E) manual called for a max of 2600 RPM and 36 lbs boost, though pretty much everyone figured out within a few months that it could be increased to 56" or 57" and 3,000 rpm, and some went considerably above that.

By the time the Soviets got the P-39 I believe the higher boost and RPM limits were already known, which is probably significant, and they had worked out better procedures for maintaining the oil cleanliness. I'm not sure how much higher octane fuel they had, I've seen different claims on whether they were using Russian or Anglo-American fuel.

 
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