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I think you missed a 'not' in that third sentence.
No I AM responsible for others
I mean, I have the various versions of the manual, that is a direct screenshot from it. I never said that later manuals didn't increase the RPM, but the original ones had much lower limits. Some were in the 40s but none showed 57" and 3,000 RPM until the end of 1942.
Several different models of Yak fighters were being tested in October 1943: improved Yak-1 #23-148, Yak-1M "Doobler" (future Yak-3), reference Yak-7B for serial production, modified Yak-9 with M-105PD(PV), Yak-9TK with exchangeable engine-mounted cannon. Yak-1B was not among them - at least Stepanets did not mention it.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.
Several things are being confused here.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.
View attachment 755491
Several things are being confused here.
The 2600rpm and 36in limit is for max continuous power. Which was usually good for as long as the fuel lasted or the temperature stayed in limits. Sometimes in Early WW II they called it a 1 hour limit. This for the US.
Now in the upper left hand part of the chart they give the limits for take-off and the limits for military power.
The military power was 3000rpm at 44.6in just like the chart says. the time limit was 5 minutes. What the pilots did when in combat is where all the gray stuff comes in because the -39 engine was never cleared for an emergency rating until very near the end of 1942.
We have been over this a bunch of times before. There are graphs which will show the pressures the supercharger will give at 3000rpm at all the different altitudes.
If you over rev the engine (like use 3200rpm) you can get more pressure/power at any given altitude. But you really risk the engine. Overrevving by 200rpm increases the loads on the reciprocating and rotating parts by just under 14%. not 6.6%.
The tables and tests I've shoved are from late 1941.
What date is on your manual?
The tables and tests I've shoved are from late 1941.
What date is on your manual?
Well Venomstick121, if you hang out here long enough you'll find out that there are some topics guaranteed to get "lively" in discussion. Think "Tastes Great! Less Filling!" In the future you might want to refrain from the following:Oh god what did I start
The P-39s used the -63 engine in the P-39K and L but since they only built about 460 of them combined I don't think they much of a mark in any front. Not sure if any went to Russia,The Russians had their greatest success with Kittyhawks flying P-40K, which had the -73 engine. I assume there is an equivalent with the P-39 though I don't know which engine model.
Well, without knowing the rpms or the boost we are spitting into the wind.The Russians refer to increasing the RPM, but I believe they were just going from 2600 or 2800 to 3000. It's hard to say though because they don't get that granular in the interviews. We know that in the infamous Allison memo about overboosting they mention running at 3200 rpm in order to overboost to 70" Hg, but I have no evidence that they were doing that in Russia. I doubt it in fact, because they had enough trouble with maintenance with all the Western engines,
Thanks will do.Well Venomstick121, if you hang out here long enough you'll find out that there are some topics guaranteed to get "lively" in discussion. Think "Tastes Great! Less Filling!" In the future you might want to refrain from the following:
Steer clear of these and you should be fine.
- Any Discussion of the P-39 Involving Superlative Performance
- Any comparison of the Spitfire to the P-51 Mustang
- Any suggestion that the Lancaster was not the greatest bomber of the war
- Proposals that late war US Naval aircraft were usable in the ETO.
Welcome to the Forum!
The B-17 was the greatest bomber of WW II and remains the pinnacle of aviation achievement because it was designed by Boeing.
We're now in 2024, so I'll be calling names at anybody claiming Japanese aircraft were made of rise paper.Well Venomstick121, if you hang out here long enough you'll find out that there are some topics guaranteed to get "lively" in discussion. Think "Tastes Great! Less Filling!" In the future you might want to refrain from the following:
Steer clear of these and you should be fine.
- Any Discussion of the P-39 Involving Superlative Performance
- Any comparison of the Spitfire to the P-51 Mustang
- Any suggestion that the Lancaster was not the greatest bomber of the war
- Proposals that late war US Naval aircraft were usable in the ETO.
Welcome to the Forum!
GO Boeing!Fixed for accuracy.
Corrected the minor historical detail.The B-17 was the greatest bomber of WW II and remains the pinnacle of aviation achievement without the use of black crosses.
Corrected the minor historical detail.