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- #41
La-5F No.99391160: June 1943: M-82F: 3,202 kg.
561 / S. L.
619 / 5,790 m.
with 1700 horsepower, already achieved 561 at SL
La-5 / La-5F / La-5FN / La-7 / La-7B-20
- Thread starter Laurelix
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561 / S. L.
619 / 5,790 m.
with 1700 horsepower, already achieved 561 at SL
May I know the source of this information?
I provided control test results that were obtained for production airplanes. The difference between M-82F and FN(V) by power at the beginning of the FNV production was rather insignificant.
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- #43
542 at nominal 1570hp translates to 572km/h with 1850hp
And what? The FN prototype had 562 at nominal and 595 at TO.
The maximum speed of serial La-5FNs according to control tests of the Air Force Research Institute did not exceed 626 km/h, and the ground speed at nominal was 546 km/h (tests in January 1944).
The maximum speed of serial La-7s never exceeded 658 km/h during control tests.
In addition: La-5FN production amounted to about 3% of the total fighter production in the USSR in 1943.
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- Thread starter
- #45
546 nomial translates to 576 with 1850hp at the deck
the graph shows
574-577 at SL
635-638 at 6250m
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- #47
theres the other graph which has lower deck speed
You can simply shift this graph to the left by ~17-20 kph and you obtain very realistic values for serial La-5FNs in 1943.
According to the recollections of many Soviet pilots, a difference in _maximum_ speed of 10-15 km/h was not considered to be significant in air combat.
Hi bf109, do you have a link to these flight test reports? I'm working on some flight models for Il-2 1946 and I try to collect as much original documentation as I can to get perfs as close to reality as possible.
Unfortunately, I do not have copies of the reports. A table containing the results of tests of both prototypes and production airplanes with serial numbers was published in the magazine "Aviation and Cosmonautics" 2000/05-06 (in Russian). A scanned copy of the magazine is available on the Web.
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- #51
So i just found out something interesting...
Ash-82-111 and Ash-82-112 are both written as 'M-82A' engines and usually distinction between them isnt made.
M-82-111 appears to be the one that was rated 1330 Horsepower at Military Power, 1570 horsepower with Take Off Power
M-82-112 was the optimised more reliable upgraded version with 1400 Horsepower at Military Power and 1700 with Take Off Power
I-185 M-82A prototype for example used the M-82-111 limited to 1570 Horsepower
La-5's introduced in July 1942 used M-82-111 engines but by Late 1942 they were already switching to M-82-112's
As '112' were still replacing the '111' in serial produced La-5's in Early 1943, thats when further upgraded M-82F engine was also approved which was basically the afterburning M-82-112 engine that could maintain the 1700 horsepower regime at long periods of time.
I-185 M-82A is rated
549km/h at Sea Level -- 1570hp
615km/h at 6450m
I-185 M-71 is rated
600km/h at Sea Level -- 2000hp
680km/h at 6100m
2000 / 1570 = 1.274
∛1.274 = 1.084
549 x 1.084 = 595km/h
Seems like I-185 M-71 was eighter tiny bit more aerodynamically refined or I-185 M-82-111 didn't achieve even that full 1570 horsepower output.
Ash-82-111 and Ash-82-112 are both written as 'M-82A' engines and usually distinction between them isnt made.
M-82-111 appears to be the one that was rated 1330 Horsepower at Military Power, 1570 horsepower with Take Off Power
M-82-112 was the optimised more reliable upgraded version with 1400 Horsepower at Military Power and 1700 with Take Off Power
I-185 M-82A prototype for example used the M-82-111 limited to 1570 Horsepower
La-5's introduced in July 1942 used M-82-111 engines but by Late 1942 they were already switching to M-82-112's
As '112' were still replacing the '111' in serial produced La-5's in Early 1943, thats when further upgraded M-82F engine was also approved which was basically the afterburning M-82-112 engine that could maintain the 1700 horsepower regime at long periods of time.
I-185 M-82A is rated
549km/h at Sea Level -- 1570hp
615km/h at 6450m
I-185 M-71 is rated
600km/h at Sea Level -- 2000hp
680km/h at 6100m
2000 / 1570 = 1.274
∛1.274 = 1.084
549 x 1.084 = 595km/h
Seems like I-185 M-71 was eighter tiny bit more aerodynamically refined or I-185 M-82-111 didn't achieve even that full 1570 horsepower output.
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- Thread starter
- #52
Average Quality Lavochkin Max Speed:
La-5 / early
509km/h at Sea Level - 1330hp
580km/h at 6250m
La-5 / late
518km/h at Sea Level - 1400hp
590km/h at 6250m
La-5F
552km/h at Sea Level - 1700hp
590km/h at 6250m
La-5FN
568km/h at Sea Level - 1850hp
620km/h at 6250m
La-7
613km/h at Sea Level - 1850hp
663km/h at 6250m
La-9
640km/h at Sea Level - 1850hp
690km/h at 6250m
La-5 / early
509km/h at Sea Level - 1330hp
580km/h at 6250m
La-5 / late
518km/h at Sea Level - 1400hp
590km/h at 6250m
La-5F
552km/h at Sea Level - 1700hp
590km/h at 6250m
La-5FN
568km/h at Sea Level - 1850hp
620km/h at 6250m
La-7
613km/h at Sea Level - 1850hp
663km/h at 6250m
La-9
640km/h at Sea Level - 1850hp
690km/h at 6250m
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The "112" differed from the "111" only by the presence of a pneumatic starter instead of an electric one. The first two digits meant the reduction (11:16), and the last one - the starter type.
The unreliable operation of the AK-82BP carburetor (based on the Holley carburetor) was the main reason for the reduction of the engine's maximum power, finally the Soviets failed to improve the carburetor.
IIRC, the I-185 was equipped with pneumatic starter. The three-digit production designations were introduced after I-185 testing began.
IIRC, only the first production batch of the LaGG(LaG)-5 was equipped with electric starter ("111").
3-digit designations were used for the M-82F/FN as well.
It was a piston engine, what afterburning? The M-82F had certain differences from the M-82A (usually the letter "A" was not specified in the official instructions) - intake pipe diameter was changed, cylinder cooling fins were increased, valve timing was changed.
... due to the improvements mentioned above.
There were two different I-185s with M-82 engines. The first was a redesign of the M-71 version, whereas the second version had a redesigned fuselage corresponding to the smaller frontal area of the M-82 - the performance of this variant was better. But the major problem was unreliable engine performance, which did not allow to achieve maximum power. The M-82 was intensively improved during the I-185 trials, and Lavochkin received a slightly more refined engine (although the fundamental problem with the carburetor remained).
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The first digit represents the engine reduction (1=11:16, 2=9:16, 3=0.56)
The second digit represents the compression ratio (1= CR of 7, 2=CR of 6.4)
The third digit represents the presence or absence of a pneumatic self-starter (1=no pneumatic self starter, 2=yes pneumatic self starter)
If the 3-digit modification code end in 'И', this means the engine has a single speed transmission. If it lacks the 'И', then it has a two-speed transmission.
Ash-82FN-312 would be an engine with a gear reduction of 0.56, CR of 7, has a pneumatic self-starter and a two-speed transmission. Such examples were built at Zavod 29 in Omsk. By mid-1944 Zavod 29 mainly made M-82 engines for the Tu-2.
Such technical data likely only made its ways around organization working in close proximity with the engines. Other organizations simply recorded their reduction ratios in the accounting docs.
Attached in a sample of what such a doc looks like:
The second digit represents the compression ratio (1= CR of 7, 2=CR of 6.4)
The third digit represents the presence or absence of a pneumatic self-starter (1=no pneumatic self starter, 2=yes pneumatic self starter)
If the 3-digit modification code end in 'И', this means the engine has a single speed transmission. If it lacks the 'И', then it has a two-speed transmission.
Ash-82FN-312 would be an engine with a gear reduction of 0.56, CR of 7, has a pneumatic self-starter and a two-speed transmission. Such examples were built at Zavod 29 in Omsk. By mid-1944 Zavod 29 mainly made M-82 engines for the Tu-2.
Such technical data likely only made its ways around organization working in close proximity with the engines. Other organizations simply recorded their reduction ratios in the accounting docs.
Attached in a sample of what such a doc looks like:
Attachments
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Thanks.
I have never come across any mention of M-82 modifications with compression ratio other than 7. Apparently, this was the reason for
I apologize in absentia to G. Serov - his article describes everything correctly, it is, apparently, I myself decided to simplify the interpretation of the designation. I also apologize to the forum participants.
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This modification was intended exclusively for installation on the Il-2. I guess there were about a dozen "112I"s produced.
Source:
