Jumo 211N, P, R - looking for some good info

[tomo pauk]

Some data is available (can be forund on the AEHS site - AEHS Home ), what I'd like to know is the timing (years of design, trials etc) of the engines.

[Siegfried]

This is a google translation of wikipedia.de on the Jumo 211

Jumo 211 A
The first production version of 1937 with 1000 horse power at 2200 min -1 . 0.615 kg / hp.

Jumo 211 Ba
Run with a ground-level and loader for 5200 m nominal height. Translation loader 7.82. Reduction gear ratio of 0.595. Start power 1200 hp at 2400 rpm -1 . 0.55 kg / hp.

Jumo 211 Da
Jumo 211 Ba, but with a loader translation of 11.375 and a reduction gear ratio of 0.645, starting power 1200 hp.

Jumo 211 B, G
Jumo 211 Da, but with different gear ratios. Start power 1200 hp at 2400 rpm -1

Jumo 211 F (L, M, R)
Design with charger and improved engine cooling. power 1340 hp at 2600 min -1 . 0.54 kg / hp.

Jumo 211 J
A Jumo 211 F with intercooler takeff power 1420 hp at 2600 min -1 . 0.51 kg / hp.

Jumo 211 N
How 211 F with increased speed and boost pressure. Power 1450 hp at 2700 min -1 .

Jumo 211 P
With improved intercooling. Off power 1500 hp at 2700 min -1 .

Jumo 211 Q
Experimental version of the 211 F with exhaust turbocharger for improved performance at high altitudes.

I have a vague recollection that the Jumo 211P was intended for the Me 264 bomber and that there was a supply issue with the. Also that the aircraft was to carry about 1 hours GM-1.

The engine didn't look to bad a performer in its final versions.

[davebender]

Jumo 211 engine production.
Junkers Engines - Jumo 211
Magdeburg. 24,267 engines produced Jul 1937 to Aug 1944.
Kothen. 20,911 engines produced 1938 to Feb 1944.
Leipzig. 17,032 engines produced 1942 to Aug 1944.

As you can see, Jumo 211 engine production dropped by one third during February 1944 and ended during August 1944. When was the Jumo 211P design ready for production?

[tomo pauk]

Thanks.
Am I wrong to assume that those 3 engines were fitted with 3-speed superchargers? A time line would be nice to have, too
The Jumo 211 production was brought to the end since the factories were to produce the Jumo 213. The 211s from the title look like 1943 is the year, though without some better info we will never know how much was produced, when.

[Denniss]

From the data it looks like N/P were equivalent to F/J with a little increase in boost and rpm (+100), nothing more.
The 211R looks like a Junkers version of the AS-engines from Daimler-Benz - sacrify low-level performace for improved altitude performance by using a bigger supercharger.

B/D were the same engines, just with a different prop/engine rpm ratio. Same with F/G. I have actually no idea where the strange Ba/Da designations come from, that's something unusual and may point to a special engine version.

[cimmex]

In Germany usually the “a” behind a model number stands for the export version, so Ba/Da designations are the same as B/D but for export.
cimmex

[Shortround6]

Thanks.
Am I wrong to assume that those 3 engines were fitted with 3-speed superchargers?

two speed superchargers Tomo. They used a partially closed throttle at sea level to prevent overboosting the engine which cause the slight loss in power shown in the charts. as the plane climbed the throttle was opened until it hit 3900-4250ft area as was wide open.

[tomo pauk]

Thanks for clarifications

[davebender]

1943 Jumo 211 production decline reflects conversion of the Kothen plant to Jumo 213 production. However Jumo 211 engine production stabilized for only a few months. By April 1944 the other two engine plants were also converting while still completing a few Jumo 211 engines.

IMO RLM was unlikely to approve mass production of new Jumo 211 engine variants after January 1943. Junkers would need an 1,800 hp Uber Jumo 211 to reverse this production decision, similiar to the DB605 ASM engine.

[tomo pauk]

That depends where one wants those 1800 HP to be achieved - BMW-801 was capable for that, but not at altitudes it was needed (nobody had such an engine, unless the turbo is installed).
The Jumo 211R was able to make 1130 HP at 23600 ft (for Steig und Kampfleistung - Climb and combat) in 1943, same as the DB 605A when cleared for Notleistung (Emergency) - and that was not allways the case for DB-605As of 1943. If we run the DB-605A at Steig und Kampfleistung (1,30 ata @ 2600 rpm), it looses by some 150 HP vs. The Jumo 211R.
Wonder how well the 'late' Jumo 211s would've operated at greater boost, with better fuel and MW injection.

[davebender]

Is that better then the Jumo 213? If not then conversion to Jumo 213 production makes more sense then conversion to Jumo 211R production.

[tomo pauk]

The main question is 'when'. If the answer is 'in 1943', the conclusion is clear - the late Jumo 211s are far more viable solution than Jumo 213.

[davebender]

DB605 engine teething problems weren't fixed until the fall of 1943. Until then the DB605 was limited to something like 1,320 hp.

Junkers had excess production capacity for the Jumo 211 engine by 1942. If the 1,420 hp Jumo 211J (or later version) had been available by early 1943 I think it would have powered some versions of the Me-109G and/or Me-110G.

Of course that same excess Jumo engine production capacity could have been employed to make Jumo 222 engines. As long as Milch remains in charge of RLM you cannot count on rational German engine production decisions.

[tomo pauk]

Well, the Jumo 222 deserves a thread on it's own, if not a whole web site
The late Jumo 211s seem like good choices for Ju-88s, provided they were really reliable.

[davebender]

Bear in mind the Ju-88 was a light bomber. Critical altitude isn't all that high so you don't need an Uber supercharger. You want high speed cruise @ 4,000 meters to minimize your time in enemy airspace.