Question about "three speed and three-stage superchargers"

[Vicvega]

greetings. Defensemedia.com says "By 1945, three-speed and three-stage supercharging was in development and/or limited use, constrained by fuel ratings. " any info and examples on this ? Thanks.

 

[MIflyer]

First you should be aware that when writing in WW2 what they called "two stage supercharging" often was in reality what we should properly call "two speed supercharging."
As far as three speed supercharging, when I did my research over 23 years ago for an article on WW2 aircraft supercharging, I found only one example of three speed supercharging, and that was on the Mitsubishi Jack fighter, late in the war, when the B-29's over Japan pointed out the inadequate nature of Japan's fighters at high altitude. I understand that there were some other examples of three speed but I do not know anything about them.

The B-29 actually had three superchargers on each engine, two GE turbosuperchargers and the mechanically driven supercharger internal to the engine. But this was not three stage supercharging and merely reflected the need to accomodate the big cubes of the R-3350.

 

[Vicvega]

First you should be aware that when writing in WW2 what they called "two stage supercharging" often was in reality what we should properly call "two speed supercharging."
As far as three speed supercharging, when I did my research over 23 years ago for an article on WW2 aircraft supercharging, I found only one example of three speed supercharging, and that was on the Mitsubishi Jack fighter, late in the war, when the B-29's over Japan pointed out the inadequate nature of Japan's fighters at high altitude. I understand that there were some other examples of three speed but I do not know anything about them.

The B-29 actually had three superchargers on each engine, two GE turbosuperchargers and the mechanically driven supercharger internal to the engine. But this was not three stage supercharging and merely reflected the need to accomodate the big cubes of the R-3350.

Thanks for your answer I do now that us was the main user of turbos during second world war and superchargers being the mainstay and they were used with turbochargers. As far ad I know Turbosuperchargers used In day fighters like p-47s but mainly used on bombers.

My question is did any country produced an actual three-stage supercharger during war ?

 

[rinkol]

First you should be aware that when writing in WW2 what they called "two stage supercharging" often was in reality what we should properly call "two speed supercharging."
As far as three speed supercharging, when I did my research over 23 years ago for an article on WW2 aircraft supercharging, I found only one example of three speed supercharging, and that was on the Mitsubishi Jack fighter, late in the war, when the B-29's over Japan pointed out the inadequate nature of Japan's fighters at high altitude. I understand that there were some other examples of three speed but I do not know anything about them.

The B-29 actually had three superchargers on each engine, two GE turbosuperchargers and the mechanically driven supercharger internal to the engine. But this was not three stage supercharging and merely reflected the need to accomodate the big cubes of the R-3350.

The Jumo 213e/f had a two stage supercharger with three speeds. I believe theer was also a late model RR Griffon that was similar in this respect.

 

[Reluctant Poster]

The Griffon 101 had a two stage 3 speed supercharger and RR had developed one for the Merlin. As usual RR showed they were masters of packaging fitting the 3 speed into the same space as the two speed drive.

 

[MIflyer]

The utility of a two speed turbo over a single speed one is unquestionable. Just look at the performance graphs of a P-40E versus a P-40F; you have two "top speeds" instead of ony one. Or, better yet, get in a manual transmission automobile and try to use only one speed. I had a 1974 Corolla with a two speed automatic transmission; things were just fine up to about 40 MPH, but at higher speeds it was more strained.

If you have a turbo feeding the single speed mechanical supercharger, like the B-17, B-24, P-38, etc. the supercharging system was "infinite speed" because the turbo adjusted the wastegate as required. The same was true of the fluid coupled mechanical superchargers of the BF-109, P-63, and F-82. But when you are going to three speeds I wonder if it is really worth the effort, unless you have only a single stage. I guess if you were going to a very high altitude maybe that would be useful.

 

[BarnOwlLover]

The three speeds for the three speed Griffon/Merlin supercharger was low supercharge (LS), medium supercharge (MS) and full supercharge (FS). Packard was also attempting to design a variable speed/continuously variable speed supercharger drive for later versions of the Merlin.

 

[taly01]

I had recently been reading some Japanese documents of the J2M5 Raiden, they say it is a western misconception that it had a 3 speed supercharger. I have since found several Japanese sources that say it was a 2 speed like other Kasei engines, they even give the gear speeds, both are raised over the normal Kasei2x series.

3. The first thing I would like to mention about the Mars 26A is that the turbocharger(sic) of the Mars 26A is a 1-stage, 2-speed type. There are occasional misinformation that it is a 1-gear, 3-speed type (especially in Europe and the United States?), but I would like to say that it is clearly wrong.

The other logic proof is there is specs of supercharger heights of Kasei 26a of 2800/6800/7200m who would go to design trouble of an extra gear for 400m?

There is horrible mixing up of turbo- and super-charger terms on aircraft, even by my (google translated) source!

 

[tomo pauk]

The utility of a two speed turbo over a single speed one is unquestionable. Just look at the performance graphs of a P-40E versus a P-40F; you have two "top speeds" instead of ony one. Or, better yet, get in a manual transmission automobile and try to use only one speed.

P-40 was not outfitted with a turbo.

I had recently been reading some Japanese documents of the J2M5 Raiden, they say it is a western misconception that it had a 3 speed supercharger. I have since found several Japanese sources that say it was a 2 speed like other Kasei engines, they even give the gear speeds, both are raised over the normal Kasei2x series.

I'd agree with the notion that there was no Kasei outfitted with a 2-speed S/c drive, not even these for any J2M version.

greetings. Defensemedia.com says "By 1945, three-speed and three-stage supercharging was in development and/or limited use, constrained by fuel ratings. " any info and examples on this ? Thanks.

Got a link?

 

[Skyediamonds]

Not to complicate this discussion but with all these topics of turbocharging & supercharging along with the advantages of different speeds & stages, but shouldn't inter cooling also be a factor in determining the efficiency as well as any advantages? If so, which aircraft benefitted more?

 

[MIflyer]

but shouldn't inter cooling also be a factor in determining the efficiency as well as any advantages?

YES! Very much so. A two stage mechanical supercharger was nothing new in 1942. The XP-41 and the F4F had got there years before. But the liquid cooled aftercooler used by the Merlin 60 series was a true innovation and THAT is what made that engine a war-winner. The fact that solution was not used in the production P-63 and F-82 merely emphasizes Hooker's brilliance. By the way, Stanley Hooker was a theoretical aerodynamicist rather than an engineer with expertise in thermodynamics.

 

[sotaro]

P-40 was not outfitted with a turbo.



I'd agree with the notion that there was no Kasei outfitted with a 2-speed S/c drive, not even these for any J2M version.



Got a link?

The Aircraft Engines of World War II | Defense Media Network

A review of the development of aircraft engines among the major combatants before and during World War II, including radial, inline, and jet engines.

www.defensemedianetwork.com

 

[tomo pauk]

The Aircraft Engines of World War II | Defense Media Network

A review of the development of aircraft engines among the major combatants before and during World War II, including radial, inline, and jet engines.

www.defensemedianetwork.com

Thank you

Now, it's debunk time.

greetings. Defensemedia.com says "By 1945, three-speed and three-stage supercharging was in development and/or limited use, constrained by fuel ratings. " any info and examples on this ? Thanks.

Whenever one sees an 'official' article that does not provide sources, that should raise a red flag size of Manhattan. These make the articles found on Wikipedia equal to gospels of truth.
Examples:
All combatants had engines equipped with one or two stages of supercharging, as required for mission altitude.
**A big 'no' - there was no such thing in Germany, Italy, Japan or soviet union as 'let's just use the 2-stage supercharged version of our better engines' for the prosaic reason of not having 2-stage engines in manufacture for 99.9% or the missions flown during the war.

Early high-altitude aircraft engines used turbochargers, which were more available than a geared second stage.
**Again - no; only the Americans were using turbochargers as mainstream.

but the turbocharger was dropped for the P-39 for a number of reasons, including a need for further streamlining which deleted space for the bulky turbocharger, and because it did not have the range required for high-altitude escort or intercept anyway.
**High altitude intercept does not require long range.

Japanese and Russian engine development is not well documented.
**Or in other words, author has no wherewithal to travel to Japan or Russia (before 2023, obviously) to do the actual work.

By 1945, three-speed and three-stage supercharging was in development and/or limited use, constrained by fuel ratings.
**3-speed S/Cs were used on Jumo 213E that was using 87 oct fuel. No source for 3-stage superchargers by author. Author here glances over the fact that DB 601/603/605 S/C drives have had, in theory, infinite number of step-up ratios - a.k.a. infinite number of speeds - that is again infinite number greater than 'just' 3.

German production engines typically used hydraulic clutches to provide variable speed control for a single-stage supercharger, enabling them to avoid use of two-stage superchargers while still obtaining adequate performance.
**Nope. Only DB - among the German engines - used the variable-speed drives for their S/Cs. Reason for adequate performance of the German fighters was that main German engines were of big displacement, and fighters themselves were small. Two-stage supercharged engines still reigned supreme above 25000 ft, though.

<debunk over>

Sentences quoted - and thatt is just two screens worth - messed up the rest of the article, that seems decent.

 

[Metrallaroja]

F4U-1, F4U-4, F6F-3, F6F-5, F4F-4 all have ''3 speed'', ''2 stage'' supercharger.
Because in first speed you just bypass the 2nd stage superchager.

3 speed supercharger is nothing uncommon.
3 stage supercharger is a complete different story, I can only think on J2M4. And nvm it seems J2M4 used a turbo setup.
It seems it had a two stage supercharger + a turbo gear after supercharger crit alt, at least from what I can find.

 

[tomo pauk]

3 stage supercharger is a complete different story, I can only think on J2M4.

Why J2M4?

 

[taly01]

And nvm it seems J2M4 used a turbo setup.
It seems it had a two stage supercharger + a turbo gear after supercharger crit alt, at least from what I can find.

I think J2M4 had normal Kasei 2x series two speed supercharger + a turbocharger. They only made two prototypes a Model 32 and possibly 34, from what I can work out.

Because in first speed you just bypass the 2nd stage superchager.

Is this what USN called neutral blower?

 

[Metrallaroja]

Is this what USN called neutral blower?

yes

 

[tomo pauk]

It seems it had a two stage supercharger + a turbo gear after supercharger crit alt, at least from what I can find.

I'd say it was a 'normal' S/C (1-stage, 2-speed) + turbo, for 2 stages total. Sorta what it was experimented with Ki-100, C6N or at some Ju 388s (these saw some service)

 

[Alpakinator]

I had recently been reading some Japanese documents of the J2M5 Raiden, they say it is a western misconception that it had a 3 speed supercharger. I have since found several Japanese sources that say it was a 2 speed like other Kasei engines, they even give the gear speeds, both are raised over the normal Kasei2x series.



The other logic proof is there is specs of supercharger heights of Kasei 26a of 2800/6800/7200m who would go to design trouble of an extra gear for 400m?

There is horrible mixing up of turbo- and super-charger terms on aircraft, even by my (google translated) source!

Hey, it's great to hear that, because I came to the same conclusions, based on my few sources. However, mine don't state directly that it had 2 speed, and not 3 speed supercharger. Could you send sources you mentioned, that say, J2M5 had a 2 speed, and not a 3 speed supercharger? Also sources with J2M5 performance data would be great, cause I'm making a War Thunder bug report for fixing J2M5 engine performance. I would greatly appeciate that, because many sources have varied perfomance values.

I'll put some sources I have found. source 5 and 6 seem to give a more direct statement about 2 speed supercharger

[5] 局地戦闘機「雷電」 : 異貌の海鷲 (文春文庫) ICBN: 9784167249137
国立国会図書館オンライン | National Diet Library Online
(Not 100% sure it's from this book. I got this from this link below)
J2M Raiden Performance
[6] Famous Airplanes of the World Navy Interceptor "Raiden" | 1996| No. 61 ISBN 10: 489319058X

 

[taly01]

"Mitsubishi Heavy Industries, Ltd. Manufacturing Airplane History" (2-3)The_History_of_Mitsubishi_Aero-Engines.pdf pg.96-103 are somewhere here on this site, I think it gives the gear ratios for all Kasei 2x engines.