Making the best use of Jumo 211 series? (1 Viewer)

[tomo pauk]

The workhorse engine of the LW in the ww2, powering many important aircraft both during the initial victories and the later defeats. Never gaining the 'star' status like the DB or the BMW 801 engines had, despite it's ubiquity; granted, on the production lines it was pretty much replaced by the Jumo 213s by 1944.
Rumor has it that crates upon crates of the engines were left in Germany in 1945, since it was not needed anymore (?).

What steps might've been the useful steps in making it a more important engine? Plausible improvements to make it more attractive?
Perhaps also shipping it to the Axis allies to improve/re-engine their A/C (using the fighters like the IAR 80/81s, G.50s and MS 406 was beyond the sell date already by 1941/42)? Romanians have had a good thing going on with the Jumo-powered IAR 81 prototype, just for it to be killed by the Germans not playing the ball - M mack8 .
Note that the B4 fuel is still a given.

 

[SaparotRob]

I can't answer your query but finding crates of "new" 70 plus year old engines would be cool!

 

[tomo pauk]

The easiest way for the 211s to gain some additional ... notoriety might've been to start sending them to Italy, once there is a realization that Italy will be ill able to produce the modern engines in the required quantity. This means making more of the fighters in that can do about 600 km/h, from Macchi, Fiat and Reggianne; the later company reverted to the indifferent radials engines after the Re.2001 because the supply of DB 601s was insufficient.
This way also perhaps the Fiat G.50V or the Ro.58 might've also materialize as a service-worthy aircraft, even if the engines used are from Jumo and not from DB.
Romanians installing the 211 on their IAR fighters was discussed on this forum before.

This shuffling of the engines would've certainly meant that there is less of Jumo 211 engines for Germany, meaning for example that the Ju 87 production is even faster curtailed.

 

[Zmauky]

Lots of ideas where the excess engine could be used.
It's just a matter of when.
If we are talking about 1944 (and probably these surpluses were caused by the cessation of bomber production) then the number of ideas very quickly boils down to why they were surplus.
( Too ) weak for fighters (Avia S-199 ?) and all extra Ju 88A, He 111, Ju 87 or Ju 290 or Ju 352 would just become pennants/stars drawn on allied fighters.
And then when it could have meant something, they weren't there. For example to replace the He 111 (with DB 600) '38 or the Do 215 '40 (to release DB for fighters) even the He 112 as the second basic fighter in 1939-1941. And yes for all minor axis AF.

 

[tomo pauk]

( Too ) weak for fighters (Avia S-199 ?) and all extra Ju 88A, He 111, Ju 87 or Ju 290 or Ju 352 would just become pennants/stars drawn on allied fighters.

Avia S-199 was an example of how to make an underperformer. Post-war, the Czechs mated the draggy 109G-6 airframe with an engine that was okay in 1941-42 (the Jumo 211F), but it was badly obsolete already in 1943.
Mate a streamlined airframe (109F/G-2, MC.202, G.55V) with the 211F in 1941 and there is a competitive fighter to be had for 1941-42. Even makes sense on the bigger Re.2001, considering the 10-20% power increase over the DB 601A.
Move to the 211N by 1943 gets another 5-10% better power values (greater %-age at higher altitudes).

And then when it could have meant something, they weren't there. For example to replace the He 111 (with DB 600) '38 or the Do 215 '40 (to release DB for fighters) even the He 112 as the second basic fighter in 1939-1941.

A second iron in the fire in the shape of the 211-powered He 112 certainly looks like a no-nonsense fighter.

The engine itself could've used a bit of ... love. Like outfitting it with the swirl throttle for more power under ~5 km without the need for the hi-oct fuel - book about the Me 309 by Sharp and Douglas notes that Jumo 213 was already with the swirl throttle during the test phases in the late 1941. A 'proper' rating of the 211 series for Notleistung rpm and boost, even if it is just for 3 minutes, would've helped with power at all altitudes.

Coming out sooner with something akin to the 211R version, that traded low-alt power for high-alt power increase would've also helped.

 

[z42]

• Could a "213-lite" engine have been available earlier if they just had added a 4V head to the 211? (Also the pressurized cooling system, but this was already implemented in later 211 variants.)
• A transport plane with two 211's and steel tube+fabric+wood construction instead of the Ju 52.

 

[tomo pauk]

Could a "213-lite" engine have been available earlier if they just had added a 4V head to the 211? (Also the pressurized cooling system, but this was already implemented in later 211 variants.)

The 211R + swirl throttle = 213 lite?
As-is, it was supposed to be making 1200+ PS at 7100m, comparing with with the 213A at 3000 rpm making 1300+ PS there. At 3km, the 211R was supposed to do ~1480 PS, where the 213A was doing the same at 3000 rpm. Swirl throttle takes care of the 'gaps' that were present with the 211R, namely down low (213A @3000 rpm has extra ~130 PS at SL), and between 4 and 6 km (213A @3000rpm has about 200 PS extra).

(my humble opinion is that the supposed disadvantage of the 3-valve head for the Jumo engines is sometimes overblown)

 

[tonycat77]

A detuned version for tank production, by 1940 would be nice, Germany would get a 500-600hp class engine with similar size to the v2-34 which was derived from 1920s German aerial engine development anyway, send damaged or worn out engines to a Maybach plant to make them into a German meteor engine.

 

[tomo pauk]

Interestingly enough, there was several attempts on installing the Jumo 211 engines on the Bf 109, and some of them even flew, at least per this post on another forum (can be translated easily), also here for the facsimile of the original doc about the Dec 1942 meeting. The doc hopes for a 100 rpm increase of the 211J engine vs. what is normally making, so it can make 'a bit better power' than the DB 601E down low, while still having a 70 PS deficit at 'altitudes' ('Hoechenbereich').

The doc states the 50 km/h deficit vs. the 'normal' Bf 109F-4 - pretty sobering, although it is probably in case if the 'normal' 211J was installed, that was about 10-15% less powerful at altitude than the DB 601E. I'm also not sure why the intercooled engine is used, instead of the non-intercooled sibling, ie. 211F; intercooler will add a bit of drag, but it will also add some power.

 

[Luft.4]

Maybe this could be of some use ... or at least enough to continue scratching your heads.
Based on decoding the engine number, it is actually a Jumo 211. In my database, a lot of 129 batch Jumo 211 engines were built as F2 sub-models.
Alternatively, it could just be a typist error.

 

[tomo pauk]

Could a "213-lite" engine have been available earlier if they just had added a 4V head to the 211? (Also the pressurized cooling system, but this was already implemented in later 211 variants.)

On the theme of '213 lite' - Jumo was mooting different types of supercharging for the 213 as early as 1941, including 2-stage S/C.
(they were also mooting the - very elusive - the versions with '1-stage supercharger with axial pre-stage without intercooler', that sound suspiciously like the S-P supercharger that Turbomeca in France made for the HS-12Y-45 and on)

My idea is that a 2-stage S/C on the Jumo 211 would've been a crucial step in making that engine a really competitive one. Not a super engine by any means, but a significant improvement. Intercooler is IMO mandatory, sprinkle a bit with MW 50 and/or swirl throttle as these are available.
Trying the 211 out with the S-P supercharger would've also been interesting.

 

[tonycat77]

On the theme of '213 lite' - Jumo was mooting different types of supercharging for the 213 as early as 1941, including 2-stage S/C.
(they were also mooting the - very elusive - the versions with '1-stage supercharger with axial pre-stage without intercooler', that sound suspiciously like the S-P supercharger that Turbomeca in France made for the HS-12Y-45 and on)

My idea is that a 2-stage S/C on the Jumo 211 would've been a crucial step in making that engine a really competitive one. Not a super engine by any means, but a significant improvement. Intercooler is IMO mandatory, sprinkle a bit with MW 50 and/or swirl throttle as these are available.
Trying the 211 out with the S-P supercharger would've also been interesting.

Couldn't they add the DB supercharger system?

 

[tomo pauk]

Couldn't they add the DB supercharger system?

They probably could.
Advantages of the variable speed drive for the S/C vs. the 2-speed drive was that the power loss between the 1st and second gear is less prominent.
See here the 30 min power graph for the Jumo 211F (thick black line) and the DB 601E (red line). Variable speed drive will add as much as 100+ HP vs. the 'normal' 2-speed drive, atop to the 601E already making extra 80-100 HP (partially due to running 2500 rpm on the 30 min power setting, vs. the 211F running on 2400, and partially because it was a 4-valve head vs. the 3-valve head?).
Disadvantage of the variable speed drive was the increased heating of the engine oil under the rated altitude, sue to the slippage within the drive - the oil system will need a bigger radiator.



What both DB and Jumo engines will need is a much better S/C by some time of winter 1942/43, let alone by Summer of 1943.