Estimates of a Ju88G or R with Jumo 222?

[cherry blossom]

Slightly changing the subject, another aircraft that could have benefited from a working Jumo 222 was the He 219 which Eric "Winkle" Brown described as underpowered with the DB 603A (I found a quote at The He-219: Germany's Most Overrated Plane? [Archive] - Ubisoft Forums which is hopefully correct).

 

[Koopernic]

Slightly changing the subject, another aircraft that could have benefited from a working Jumo 222 was the He 219 which Eric "Winkle" Brown described as underpowered with the DB 603A (I found a quote at The He-219: Germany's Most Overrated Plane? [Archive] - Ubisoft Forums which is hopefully correct).

The He 219 certainly would have benefited from the Jumo 222 and would have been able to touch the mosquito. As it stands it was faster than the Ju 88 but still not enough to cope with the mosquito either to evade it when used tole as a bomber or intercept it reliably when used as a night fighter.

However it's interesting to look at the DB603 engine
DB603A 1750 hp on B4 fuel in service by mid 1943 on Me 410/Do 217M
DB603E 1800 hp on B4 fuel in mass production by September 1944 has slightly more power but much higher full throttle altitude.
DB603EM 2260hp on C3+MW50 version of above might have powered Ta 152C and Fw 190D9 bar shortages of C3 and mistaken weight calculations by Focke Wulf which mistakenly assessed the engine as 128kg heavier than the Jumo 213A.
DB603LA 2260hp on B4+MW50 used on Ta 152C. This engine had a two stage super charger, a few delivered to Luftwaffe n Ta 152C.

Mention should also be made of the 1900hp DB603G which flew on various prototypes as early as 1942 using C3 fuel and a better super charger but was never produced. There was also the DB603AA which was a Db603A tuned for High altitude that compromised takeoff power a little.

In the future, scheduled for about June 1945 was the DB603L of 2400hp, it added an intercooler. Beyond that the 2800hp DB603N was on the bench.

If this program is advanced by just 1 year then the He 219 issues would be solved to a considerable extent. I can't help thinking that an opportunity was missed and that despite their smaller "size" they might have provided almost the same power levels had the effort been put into them.

The RAF had their Napier Sabre and Griffon, the USA had their PW R-2800 but the Luftwaffe received this class of engine only 1 to 2 years latter. Granted the inferior fuel would have always put them behind by 10% or so anyway but it's the belated introduction rather than slightly lower power level that did the damage. The BMW 801 did fairly well filling in the gap but still not enough.

 

[Koopernic]

That would be crazy since DB601 / DB603 / DB605 shared development technology. Better to keep all three and kill the entirely new 24 cylinder DB604 engine.

Personally I would go so far as to kill Jumo 222 and begin development of Jumo 213 engine during 1937. However if Germany is determined to have a 24 cylinder engine program then the Junkers program is the only one I would fund.

I'm thinking that the DB603 is an older design than the DB605 so the 603 might beat the 605 into service by a considerable margin. What then does that do to perception of a Me 109 replacement or to development of the Italian series 5 fighters.

 

[wiking85]

That would be crazy since DB601 / DB603 / DB605 shared development technology. Better to keep all three and kill the entirely new 24 cylinder DB604 engine.

Personally I would go so far as to kill Jumo 222 and begin development of Jumo 213 engine during 1937. However if Germany is determined to have a 24 cylinder engine program then the Junkers program is the only one I would fund.

Can't develop the 213 in 1937, the basic engineering tech did not yet exist; they started in 1939 with a research study for a reason and then it took years to make it work thereafter. So the 222 was the only game in town until 1940 and then the 222 would have been ready faster at a higher HP with better growth potential. The DB603 though had better potential than the 213 in the long run and would have benefited from not being cancelled, cancelling the 604 and not getting into all those wacky derivatives like the 606/10 and 613 and V16 variant of the 603.

 

[davebender]

Not really since DB605 is just a further development of DB601E. I'll hazard a guess that boring block from 34 liter to 35.7 liter (to produce DB605 block) contributed no more then 5% to future DB601E HP increases. So a fully developed DB601 engine is likely to produce 1,950hp rather then 2,000hp of historical DB605D.

 

[davebender]

I disagree.

Junkers and Daimler-Benz were fierce commercial competitors. That can work wonders with competitive bidding.

DB603 prototype number 1 produced about 1,500hp during 1937 at time program funding was cancelled. There's no reason to think a 1,600hp production engine cannot be in service during 1941 (i.e. after 4 years of additional development).

If Luftwaffe announce they intend to switch Ju-88 airframes to DB603 engines during 1941 you can count on Junkers moving heaven and earth to get Jumo 213 engine production ready as early as the DB603. Might not make it but I wouldn't bet against it as Luftwaffe engine contract worth a billion RM is at stake. Furthermore DB603 and Jumo 213 would keep on competing for engine contracts resulting in faster then historical development for both engine.

The benefits of letting "greedy" capitalists compete rather then favoring certain engine projects such as BMW801. 8)

 

[wiking85]

I disagree.

Junkers and Daimler-Benz were fierce commercial competitors. That can work wonders with competitive bidding.

DB603 prototype number 1 produced about 1,500hp during 1937 at time program funding was cancelled. There's no reason to think a 1,600hp production engine cannot be in service during 1941 (i.e. after 4 years of additional development).

If Luftwaffe announce they intend to switch Ju-88 airframes to DB603 engines during 1941 you can count on Junkers moving heaven and earth to get Jumo 213 engine production ready as early as the DB603. Might not make it but I wouldn't bet against it as Luftwaffe engine contract worth a billion RM is at stake. Furthermore DB603 and Jumo 213 would keep on competing for engine contracts resulting in faster then historical development for both engine.

The benefits of letting "greedy" capitalists compete rather then favoring certain engine projects such as BMW801. 8)

Not really, because it required the development of a new cooling system to be able to make the 211 smaller and faster, plus it required work on strengthening the crankshaft properly.

I means the 211 was just put into production by 1937, it was entering testing in 1936.
https://en.wikipedia.org/wiki/Junkers_Jumo_211
https://en.wikipedia.org/wiki/Junkers_Jumo_213

The 213A (the main production series, with single-stage two-speed supercharging)[3] first ran in 1940, but experienced lengthy delays before finally being declared "production quality" in 1943. Production was extremely slow to ramp up, in order to avoid delays in the existing Jumo 211 production. By the time the engines were available in any sort of number in 1944, Allied bombing repeatedly destroyed the production lines. Production of the A model was limited to about 400-500 a month for most of 1944/45.

The pressurized cooling system entered testing in 1939 and wasn't proven viable until 1940 and the first production version of the pressurized cooling 211 wasn't available until 1941.

 

[davebender]

By 1939 RLM had already committed to the purchase of more then 1,000 Jumo 211 engines per month. Compared to about 200 DB601 engines per month and no DB603 engines.

In such a procurement environment what incentive did Junkers have to spend money on Jumo 211 development? Jumo 211 engine was going to be purchased in large numbers without regard to performance of contemporary Daimler-Benz engines.

Force Junkers to compete with Daimler-Benz for engine contracts and their Jumo engine development center will get larger in a hurry.

 

[wiking85]

By 1939 RLM had already committed to the purchase of more then 1,000 Jumo 211 engines per month. Compared to about 200 DB601 engines per month and no DB603 engines.

In such a procurement environment what incentive did Junkers have to spend money on Jumo 211 development? Jumo 211 engine was going to be purchased in large numbers without regard to performance of contemporary Daimler-Benz engines.

Force Junkers to compete with Daimler-Benz for engine contracts and their Jumo engine development center will get larger in a hurry.

Why did they even bother to develop the 213 at all? Because they had ordered the 603 later in 1939 and Jumo was trying to stay competitive.
https://en.wikipedia.org/wiki/Daimler-Benz_DB_603
The racing stunt and start of the war reactivated the 603 project, but prior the 213 work had begun to have a back up in case the 222 didn't work out and as a further development to also leapfrog the new 601:
https://en.wikipedia.org/wiki/Junkers_Jumo_213

By contrast, the 1940 Daimler-Benz DB 601E used a pressurized coolant system that ran at the same pressure regardless of altitude, raising the boiling point to about 110 °C. This allowed it to use considerably less water for the same cooling effect, which remained the same at all altitudes. Although otherwise similar to the Jumo 210 in most respects, the 601 was smaller and lighter than the 211, and could be run at higher power settings at higher altitudes, making it popular in fighter designs. The 211 was relegated to "secondary" roles in bombers and transports.

The Junkers Motorenwerke firm was not happy with this state of affairs, and started their own efforts to produce a pressurized cooling system as early as 1938. Experiments on the 211 proved so successful that it became clear that not only could the engine be built smaller and lighter (by reducing the water requirement),[2] but could be run at higher power settings without overheating. Additional changes to strengthen the crankshaft and add a fully shrouded supercharger for increased boost resulted in the Jumo 211F model, which delivered 1,340 PS (1,322 hp, 986 kW) at 2,600 RPM, up from 1000 PS at 2,200 RPM in the first version 211A.

But this was only the beginning. After redesigning the engine block to a smaller external size to suit the increased cooling power - while keeping the same 150 mm x 165 mm bore/stroke figures, maintaining the 35 liter displacement of the Jumo 211 series - and then further increasing boost settings on the supercharger, the resulting 213A model was able to deliver 1,750 PS (metric hp) at 3,250 RPM. This made it considerably more powerful than the corresponding DB 601E which provided 1,350 PS, and about the same power as the much larger DB 603. Junkers decided to go after the 603's market, and placed the 213's mounting points and fluid connections in the same locations as the 603, allowing it to be "dropped in" as a replacement, with the exception of the Jumo's standard starboard-side supercharger intake (Daimler-Benz inverted V12 engines always had the supercharger intakes on the port side).

Jumo had all sorts of incentives to work on the 213 and develop the 211 because Daimler wasn't sitting still and RLM demands were continuing to increase. Both the 601 and 603 were competition, but as it was Jumo started on the pressurized cooling system in 1938 after making sure the Jumo 211A was in mass production and upgradeable in 1937. It was the experiments starting in 1938 that even let them know that the 213 was a viable option, so your 1937 start date is not even viable given they didn't know something like that was an option, they were just interested in upgrading the 211, but because that work was so successful they started working on an option for the 213 in 1939.

So in terms of technical knowledge they were too busy working on the 211A and B follow up in 1937 to start considering pressurizing it until they had the basics out of the way then that path led them to realize they could do the 213 in 1939 and work started with RLM approval and funding in 1939 as a backup to the 222 and as competition to the DB603.

 

[davebender]

Then Daimler-Benz receives 1941 engine contract for Ju-88 bombers by default.

Too bad all military procurement decisions aren't so obvious.

 

[Shortround6]

Then Daimler-Benz receives 1941 engine contract for Ju-88 bombers by default.

Too bad all military procurement decisions aren't so obvious.

Yep, Obvious. The facts that DB had been promising quantity deliveries and power levels well in excess of what they actually delivered for several years was a sure way to bump Jumo out of the Market

 

[wiking85]

Then Daimler-Benz receives 1941 engine contract for Ju-88 bombers by default.

Too bad all military procurement decisions aren't so obvious.

What are you talking about? This makes no sense. Daimler production was what it was and technical details were understood by the RLM and LW. I'm talking about what was the historical case in terms of the R&D programs and you're not make any sense whatsoever and clearly aren't understanding how engine development worked or contracts were awarded during this period.

 

[Koopernic]

My understanding is that the Jumo 211 was always 'lightly' pressurised but at high altitude the lowering of boiling point and the lower permitted differential pressure between the cooling loop and high altitude ambient limited the cooling system cooling capacity at high altitude. The pressurised cooling circuit was introduced in the Jumo 211E which was soon replaced by the Jumo 211F and latter supplemented by the intercooled Jumo 211J.

The Jumo 211 proceeded fairly quickly since it was essentially a scaled up Jumo 210G and was not overly ambitious. I speaks well of an evolutionary approach.

Advanced versons of the F and J were respectively the N and P.

Nevertheless the engine could not produce the kind of superior aircraft the Luftwaffe needed for the sake of the lives of its pilots.

An engine in the Jumo 222 class is needed, at some point, as this configuration offered not only 2500hp but 3000hp and even 3500hp in the form of the 36 cylinder version. (all without WEP)
1 It is needed because in 1942 no one knows whether the jet engine will really work.
2 It is needed simply because of progress and the need to produce fast bombers that can evade interception as much as possible.
3 It is needed for large powerful night fighters.
4 It is needed for the super fast fighter aircraft if the jets fail.

5 At some point, if a remarkable thing happened, and the Germans knock the USSR and Britain out of the war and Rommel thereby occupies Nth Africa we have a situation where the a intercontinental war needs to be waged against the USA and Canada with big aircraft like the B-36 trading blows with 6 engined Ta 400s, Me 264 etc.

One view through the retrospectoscope the best outcome would have been
1 Daimler Benz Accelerates rollout of the DB603 series thereby enabling aircraft such as the Fw 190D, Ta 152, Ju 188A, Ju 88S3, Ju 88G6/G7, , Ju 388, He 219, Ta 154 Moskito, Me 410, Do 217, Do 335 Some of these aircraft could work on weaker engines or the BMW 801 but all could be deployed earlier and improved earlier if one assumes but an earlier rollout of the engines and then an earlier deployment of increased power ratings.

Some of these aircraft are beyond saving but having 1900 instead of 1750hp or having 2100/2260 instead of 1900 would make a difference.

The DB603 should have been available in 1941/42 about the same time as the R-2800 and Sabre.

2 Junkers continues with the Jumo 222 and rolls it out as a 2000hp engine in December 1942 relying on improvements and maturation to grow the engine. If rated to only 2000hp its power to weight ratio is no better than the DB603, it is heavier but also 14% more powerfull. It should be an overall gain. I can see it being applied to advanced forms of the Ju 88, He 219 and Do 217.

I can see what happened after the weight growth of the Ju 288A into the 3000hp DB610 equipped Ju 288C, Junkers and/or the RLM realised that they too would need to match 3000hp, hence the bored out Jumo 222C/D.

Obviously when the Jumo 222 was not given a production contract and the Ju 288A and B market disappeared the Jumo 213 must have become more important to Junkers as its future 222 engine had an uncertain future (production slated for late 1944).


Having said that, the average time from start of an engine program to operational service seems to have been 6 years, a few engines did better, many of which suffered.

The DB605 was more than a 5% bored out and bulked up DB601. It replaced the roller bearings in the crankshaft with journal bearings. The introduction of a high pressure lubrication circuit to go with this didn't seem to go smoothly. I'm not sure of roller bearings were used on the crankshaft or on the big ends of the king rod or both. Either way its 6,7 or 13 bearing races. This of course gets us to our favourite mastermind topic of 'bearing production in the Reich 1940 to 1945'.

This is why I suggested the complete abandonment of the DB605, the persistence with advanced forms of the DB601E for a little longer followed with the replacement of the Me 109 with a DB603 powered fighter. The 605 could mature but it took too long, 1944, for the high powered versions.

I suspect the 603 also used journal bearings.

The DB engines are respectable, they provided excellent power on poor fuels and excellent altitude performance for a single stage superchargers. It was the absence of advanced SC that diminished this engine.

 

[davebender]

Let's suppose DB601E receives continued development. No DB605A.

Wouldn't 1,450HP DB601XX engine which enters service during 1942 (ILO DB605A) employ a similar lubrication system? Presumably Daimler-Benz made the lube system change because it was required by higher power levels.

 

[Koopernic]

Let's suppose DB601E receives continued development. No DB605A.

Wouldn't 1,450HP DB601XX engine which enters service during 1942 (ILO DB605A) employ a similar lubrication system? Presumably Daimler-Benz made the lube system change because it was required by higher power levels.

I'd assume it was an economy issue or an issue of anti friction bearing production capacity. To be frank, I don't know. It's an interesting issue.

My understanding is that the DB601 didn't receive a highly pressurised cooling circuit till the 601N or 601E so it may not have been far ahead of the Jumo 211

 

[Denniss]

601N had standard cooling if i remember right. AFAIR the 605 used lower quality bearings to enable higher possible production whereas the 601 used high quality bearings. Don't know what the 603 used.

 

[wiking85]

601N had standard cooling if i remember right. AFAIR the 605 used lower quality bearings to enable higher possible production whereas the 601 used high quality bearings. Don't know what the 603 used.

I don't think it did, it was rated for higher altitudes and was supposed to take advantage of the benefits of C3 fuel, which it was unable to do for some reason.
Kurfürst - DB 601, 603, 605 datasheets - DB 601 N

 

[Koopernic]

I don't think it did, it was rated for higher altitudes and was supposed to take advantage of the benefits of C3 fuel, which it was unable to do for some reason.
Kurfürst - DB 601, 603, 605 datasheets - DB 601 N

Early Me 109F2 with the DB601N engine as well as Me 109F4 with the DB601E engine both seems to have ended up on the same power and boost settings in 1942m (1.42ATA). The DB601N did it with high octane C3 fuel while the DB601E did it using tricky camshaft and tunable intake ports on B4 fuel. Both aircraft must have had the same performance.

 

[Denniss]

601N was specified for 1.35 ata. At ~1942m the 601N had ~1250PS, the 601E had ~1450PS
With non-derated engines the F-2 was supposed to achieve ~610 km/h and the F-4 in excess of 650 km/h (had new prop with wider blades)

 

[kool kitty89]

The He 219 certainly would have benefited from the Jumo 222 and would have been able to touch the mosquito. As it stands it was faster than the Ju 88 but still not enough to cope with the mosquito either to evade it when used tole as a bomber or intercept it reliably when used as a night fighter.

Wouldn't the Ar 240 have a better chance at being a good high speed nightfighter with DB-605s or maybe 603s/213s? (or 601Es or 211Js earlier on)

That aircraft seems like a closer example of being as small and streamlined as possible while still large enough to carry radar. (plus in development much earlier than the 219, less complex, and much less dependent on high powered engines)

I'm thinking that the DB603 is an older design than the DB605 so the 603 might beat the 605 into service by a considerable margin. What then does that do to perception of a Me 109 replacement or to development of the Italian series 5 fighters.

The Fw 190C seems the best place for the 603 in as far as single engine fighters. Foregoing the 605 and either keeping the 601 in production alongside the 603 or switching to the 603 alone if demand was high enough would make a great deal of sense.

And early-war (perhaps 1500 ps) 603 could have meant the Fw 190 being adapted to that engine much sooner, quite possibly foregoing the 801 powered variant entirely.

Since the Jumo 222 was flight testing Ju 288A prototypes at 2000hp in December 1941 it would be reasonable to assume that it could be in production, as a reliable engine, 1 year later in December 1942 also at 2000hp.

Might not there be other alternatives? Bramo apparently had the 329 on the bench making its projected 2000 ps in 1938 before work was stopped to focus on BMW designs. Continuing that or putting immediate emphasis on an 18 cylinder design using the 801's cylinders (but much more conservative than the 802) in its place might have allowed for a 2000+ PS class engine much sooner and particularly suitable for bombers.

I'm less well versed in the differences between the BMW 139 and production 801, but if the original (single speed supercharged, lighter) 139 was reliable enough to mass produce earlier than the 801, perhaps they should have stuck with both of the earlier designs (139 and 329) and gotten them into production as soon as possible.

Cancel the Jumo 222, DB 604, and advanced piston engine BMW projects and focus on the 211/213, 601, 603, 139, and 329. Probably continue BMW turbocharger work too.

Not really, because it required the development of a new cooling system to be able to make the 211 smaller and faster, plus it required work on strengthening the crankshaft properly.

I means the 211 was just put into production by 1937, it was entering testing in 1936.
https://en.wikipedia.org/wiki/Junkers_Jumo_211
https://en.wikipedia.org/wiki/Junkers_Jumo_213


The pressurized cooling system entered testing in 1939 and wasn't proven viable until 1940 and the first production version of the pressurized cooling 211 wasn't available until 1941.

Still, with all focus put on the 211 project (including 213 development thereof), it should go more quickly/smoothly than was the case diverting resources to the 222. (for that matter, diverting resources to allow the Junkers airframe and Jumo teams working on jet engines to continue independent developments should have helped a lot -Wagner/Muller's team staying at Jumo rather than leaving for Heinkel/Hirth)

The DB605 was more than a 5% bored out and bulked up DB601. It replaced the roller bearings in the crankshaft with journal bearings. The introduction of a high pressure lubrication circuit to go with this didn't seem to go smoothly. I'm not sure of roller bearings were used on the crankshaft or on the big ends of the king rod or both. Either way its 6,7 or 13 bearing races. This of course gets us to our favourite mastermind topic of 'bearing production in the Reich 1940 to 1945'.

This is why I suggested the complete abandonment of the DB605, the persistence with advanced forms of the DB601E for a little longer followed with the replacement of the Me 109 with a DB603 powered fighter. The 605 could mature but it took too long, 1944, for the high powered versions.

Agreed, this is more or less what I was suggesting above.

The DB engines are respectable, they provided excellent power on poor fuels and excellent altitude performance for a single stage superchargers. It was the absence of advanced SC that diminished this engine.

The DB 605 with the 603 supercharger seems like it might have been enough so long as it had featured an intercooler. I doubt a 2-stage arrangement would have managed much or any better without intercooling. (the 605ASM managed rather well with WM/50 applied for charge cooling and ADI, intercooling should be a more efficient alternative)

I'd assume it was an economy issue or an issue of anti friction bearing production capacity. To be frank, I don't know. It's an interesting issue.

My understanding is that the DB601 didn't receive a highly pressurised cooling circuit till the 601N or 601E so it may not have been far ahead of the Jumo 211

I believe the DB 601M used in the He 100 had a high pressure cooling system, but that aircraft employed surface cooling rather than a conventional radiator. (at least some of the features like the steam separator -a sort of deairator- and condenser carried on in most or all pressurized liquid cooled german engines)

There was more information on this in one of the Fw 187 threads.