Jumo 211 series as alternative for the DB-601/605 and/or BMW-801 in fighter AC?

[tomo pauk]

The workhorse of the LW, Jumo 211 series of engines, was foremost to be found in bomber/attack planes, plus night fighters.
Wonder how well it would be suited to replace the other 2 (3?) lines of engines in the single engined fighter AC, namely the DB 601/605 (licence models included) and BMW-801. The time frame of interest is from early 1941 until mid 1944, when the Jumo 213 and DB 605AS become available in numbers.

 

[Shortround6]

I think we need a timeline for the Jumo 211, as to which versions were introduced when. And in numbers, a few promised versions of the 211 showed up more than a few months late.

 

[tomo pauk]

The real production (even small series) of the Jumo 211N/P/R is so far a mystery for me. The earliest dates seem to be mid 1943 for the -N, late '43 for the -P (the small series of the Ju-88P-4 had those) and start of the 1944 for the -R.
Perhaps we could discuss 1st the 1941-42 time frame, when the -F and -J were available?

 

[davebender]

Jumo 211F might work for the Me-109F and G if the engine has a decent supercharger. Junkers certainly had plenty of production capacity for this engine by 1941.

 

[Denniss]

Mtt would have to redesign and rebalance the Bf 109 for Jumo 211: heavier, dimensions a bit different, supercharger on the other side, many more switches for engine control (speed switch, lean/rich switch and others). Also it had a less power than DB engines and the power curve was not smooth like with DB engines..

 

[tomo pauk]

Yep, I guess such a tightly packed fighter as it was the 109 would 'defy' the installation of another type of the engine. As for the engine powers, the un-restricted DB-601E is the one that really has the greater power.
Prior that (1941) the issue is not that clear cut. More so if we compare the DB-601N with the 211F/J - in Steig Kmpfleistung, the Jumo-211F have the some 5% more power above 5 km (albeit at more weight). The 211J is comparable with 601E, in second half of 1941. Between 2 and 4 km, St-und-kmpf, the 601E has the edge (smooth power curve, due to the hydraulically driven supercharger), but the 211 can engage the Notleistung.

Now, what about the Italian fighters with Jumo 211? The license-built DB-601Aa was available, in numbers, just for Macchi. With 211s available, the Reggianne and Fiat could up-engine their planes with something better than local radials. It would be also better than the 601Aa.

added: I've just read that Ju-87D-8 have had the Jumo 211P installed, so that one seem to be built in at least some numbers. Will keep digging The D-8 seem to be an elusive bird...

 

[DonL]

Some impressions about a Bf 109 with Jumo 211 F engine.

Avia S-199 - Wikipedia, the free encyclopedia

One of the biggest problem was, that with the Jumo 211 it was impossible to install the engine cannon through the prob.
Also the the prob himself makes realy problems.

I could not appreciate if the Czechoslovakia aviation industry have not the ability to produce an other prob for a fighter a/c or if the prob of the He 111 was the only possible way.
Anyway this a/c wasn't realy a winner and the changes were realy big and not real good for the Bf 109.

 

[Denniss]

The 211J was not suitable for the Bf 109 - where to put the intercooler?
Reggiane built a lot of Re.2001 with the italian DB 601.

The loadplan for Ju 87 D-7/D-8 lists a 211J engine but you'll never know.
BTW: D-7 = D-1 with D-5 wings, D-8 = D-3 with D-5 wings.

 

[tomo pauk]

Some impressions about a Bf 109 with Jumo 211 F engine.

Avia S-199 - Wikipedia, the free encyclopedia

One of the biggest problem was, that with the Jumo 211 it was impossible to install the engine cannon through the prob.
Also the the prob himself makes realy problems.

I could not appreciate if the Czechoslovakia aviation industry have not the ability to produce an other prob for a fighter a/c or if the prob of the He 111 was the only possible way.
Anyway this a/c wasn't realy a winner and the changes were realy big and not real good for the Bf 109.

The S-199 was a troublemaker, no point to defend it too much. I would not, however, call a comparison of S-199 vs, say, 109G-6 - the 199 was using a 1941 vintage engine.
The issue seem to be the prop (Czech problem, but not German?), augmenting the issues of the inclined undercarriage. I agree that disability to carry a hub cannon looks like a problem; the two cannons in gondolas turning the liability into asset in German case? The 211 in Friedrich airframe would have no HMG bulges and fixed tailwheeel, so the resulting fighter would be faster than the S-199 (199 managing 580 km/h); Gustav's airframe was also heavier.

The 211J was not suitable for the Bf 109 - where to put the intercooler?

Mount the wider casing under the engine, so the oil cooler and intercooler can be sited side by side.

Reggiane built a lot of Re.2001 with the italian DB 601.

252 copies; MC.202 was produced in 1200 examples.

The loadplan for Ju 87 D-7/D-8 lists a 211J engine but you'll never know.
BTW: D-7 = D-1 with D-5 wings, D-8 = D-3 with D-5 wings.

Seem like the D-7 was a recycled D-3, and the D-8 was the recycled D-5? The 'recycling' was involving installation of the Jumo 211P's, question is how much and when (second half of 1943?)the 211Ps were installed. BTW, was any other 211 featuring the intercooler, other than the 211J?

 

[Shortround6]

The S-199 may have been cobbled together from available pieces. DB had at least two different gear ratios for the DB-00/605 series depending on fighter or bomber use. I am not sure if the bomber engines could take a cannon. The Jumo 211 was supposed to take a hub gun in the initial stages. the Jumo 210 certainly could. A Jumo 211 fighter engine may have had a different gear ratios (smaller prop?) and different crank to prop spacing and accessory arrangement allowing a Hub gun. The Czechs were either taking Jumo 211s out of warehouse storage or building them from parts left on the assembly line at the end of the war.
A properly planned Jumo 211 and propeller combination may have had fewer troubles even if perhaps not as good as the DB 601/5 versions.

 

[davebender]

From mid 1940 onward most Me-110s were assigned to the night fighter force. That might be a good candidate for Jumo 211 engines.

 

[yulzari]

The Czechs were going to build DB engined 109s from available post war parts and production lines but the DBs were lost in a lost in an explosion so they had to turn to Jumo 211s which were made for He111 use. They would have deeply preferred the DB engined S-99 but had to go with the Jumo 211 S-199.

 

[davebender]

Czechs were going to build DB engined 109s from available post war parts and production lines but the DBs were lost in a lost in an explosion so they had to turn to Jumo 211s which were made for He111 use.

Me-109s weren't the only German weapons which resumed production in post war Czechoslovakia. They also resumed production of MG34 machineguns, Hetzer SP AT guns, Sd.Kfz.251 APCs and quite a few other things.

France continued production of Ju-52 transport aircraft.

Poland probably acquired some German factories too.

Norway gained aluminum smelters built by Germany. Not sure how much good this did as there was probably a massive over production of aluminum during the late 1940s.

 

[tomo pauk]

The V-12 in the front of the Fw-190 (with enough of the lead time, the Jumo 211/213 being the candidates) enables it to carry, for example, 3 cannons of identical ballistics (2 in wing roots, one as a motorkannone). No cowl MGs here, of course; less barrel openings chutes means also less drag. Once the USAAF steps up the daylignt bombing campaign, the MK-108 can replace the central weapon (so we arrive into weapon layout of the Ta-152H) - 20mm cannons can hit the escorts, while 30mm can hurt the bombers.
One cannot but wonder just how bad a mistake it was not to install the DB-603 on the Fw-190s in 1943, both from performance and weapon flexibility viewpoints.

Now we might take a look at how the Jumo 211 compares with BMW 801C and the restricted 801D (a situation before Oct 1942). The BMWs were, at least on paper, very powerful machines. They were, also, troublesome items, taking a lot of effort from ground crews to keep the Fw-190s operative. The Jumos beat them in that category. Comparing the drag of the late Fw-190s, the V-12 engined D-9 comes easily ahead of the radial siblings - meaning that a D-9 is faster than the A-8/A-9 on same HP. The intake part of the engine played the part, too; the exhaust thrust being easier to harvest from the Jumo 213, because of shorter exhausts?
Anyway, I've put together a chart that depicts the Jumo 211F/-J, BMW-801C (both Notlesitung and Steig Kampfleistung), and the restricted 801D (Notleistung; St Kmpf leistung being similar to the 801C). The BMW offers, on St. Kmpf, more power, cca 16% more vs. the 211F, but only 8% more vs. the 211J. Not enough to overcome the radial's drag, let alone when the ram effect and easier gain of the exhaust thrust are calculated in?

added: if I'm not mistaken, the Jumo 211F supercharger was operated by the automatic device ("autom. Schaltgetriebe", as noted above the graph)?

 

[Denniss]

Jumo 211P was the intercooled variant of the 211N, gaining 50 PS over it. 211J gained 80 PS over the 211F though.
Mounting the intercooler side-by-side with or below the oild cooler results in more drag and speed loss.
The Ju 87 D-7/D-8 loadplan shows a 211J engine and states the wing changed for the D-1 and D-3 models to get the D-7 and D-8.
Autom Schaltgetriebe = automated Low/High gear switching, AFAIR triggered by altitude.

BTW what's a Hetzer? I only know Jagdpanzer 38 (with or without the (t) suffix).

 

[davebender]

Hetzer = Jagdpanzer 38(t). About 15 tons.

Essentially an enlarged and improved Marder III Ausf.M which it replaced on Czech assembly lines.

Hetzer design was similiar to the Jagdpanzer IV / 48 but about 2/3rds size (15 tons rather then 25 tons). You cannot fit 25 tons of stuff in a 15 ton bucket so the Hetzer was very cramped. Like the He-162 fighter aircraft it was a design born of desperation.

 

[tomo pauk]

Jumo 211P was the intercooled variant of the 211N, gaining 50 PS over it. 211J gained 80 PS over the 211F though.

Okay.

Mounting the intercooler side-by-side with or below the oild cooler results in more drag and speed loss.

I've already admitted that Bf-109 was a too tightly knit to allow for any major changes. The increased drag speed loss would've been compensated by increased power, while the rate of climb can be only increased, when comparing intercooled vs. non-intercooled Jumos. Od course, an power egg instalation can solve that easily, with all 3 coolers located in the annular radiator; beneficially to the streamlining, too. Provided the plane can be re-balanced since the radiators went from back to front.
The resulting Bf-109 would look much like the Bf-209-II, ie. the distant relative of the Bf-109 with Jumo 213 onboard.

The Ju 87 D-7/D-8 loadplan shows a 211J engine and states the wing changed for the D-1 and D-3 models to get the D-7 and D-8.

If its not too much a problem, could you please post the docs about the late Ju-87s?

Autom Schaltgetriebe = automated Low/High gear switching, AFAIR triggered by altitude.

Cool, my German is in good shape then.

BTW what's a Hetzer? I only know Jagdpanzer 38 (with or without the (t) suffix).

Yep, the Hetzer nickname popped out some time post war?

 

[Denniss]

Hetzer was a suggested byname for the Jagdpanzer 38(d), an enlarged version of the JPz 38(t).

BTW dave's image is not of a Marder III Ausf.M, that's the first improvised version with a soviet gun and very high silhouette. The JPz 38(t) or G-13 image is a copyright violation from Wikipedia (neither source nor license nor author stated).

 

[davebender]

That's what I get for being lazy and using Wikipedia for a source.

Hopefully this is the correct SP AT gun.
Marder (Marten) Series