Ideal Luftwaffe starting 1/1/1936

[wiking85]

Other than the bomb bay limitations and external bomb racks the V5 prototype of the Ju88 seems like the ideal version of the 1936 design. The aerodynamics was sound; I'll post a picture later about the changes to the prototypes.
Edit:

Also the 'Schnellbomber' version S-series (sorry about the bad scan, what's blurred isn't that important):

 

[wiking85]

So assuming we get our pet project, a 330mph top speed defenseless non-diving 2 crew Ju88 with a modified bomb bay using two Jumo 211B engines, it would not be the primary bomber of the Luftwaffe at any period; it would be a specialist aircraft, as it lacked the payload and range to be a medium bomber; this leaves us with the He111 as the primary level bomber in 1939. Without the Ju88 getting all of the OTL resources, including Heinkel production facilities producing for the Ju88, the He111 would be the most numerous bomber IMHO and the Do17 would have already been phased out in 1939. Assuming they have proper planning the LW could order the He111H to be prepared first instead of the He111P, the DB601 equipped unit, due to the large Jumo production capacity. The He111P was ready IOTL for mass production in November 1938, but was stymied in production due to the lack of DB engines; here if the He111H is produced in late 1938 first, then mass production could be ordered for this type for nearly a year; historically the H-series was ready in March and lacked production resources due to the Ju88 program eating up 50% of all aviation production resources (yet turned out only about 5 dozen units for all of 1939), but still delivered over 400 Heinkel bombers by September. A 5 month head start and more production resources would mean that the Do17 is totally out of production and service in 1939, while the Heinkel is in deep production by September 1939; assuming the Ju88 is ready for production in March 1939, as it has been predicted it would be if the dive requirement isn't added, then it too can phase in about 1 Geschwader pre-war. But its need is relatively low and can be built up by May 1940 without issue; in the meantime the Heinkel 111 is the workhorse of the LW: it can do just about everything they need in 1939-40 minus recon, CAS, and night fighting. With proper planning I don't see why by the start of the invasion of France there couldn't be well over 2000 units produced, so there is a deep reserve and full ration strength at the front of this model.

Despite limited Ju88 production resource with an early start and less technical issues that cropped up thanks to the landing gear in late 1939 would also probably see even more Ju88s in service by May 1940 than historically due to the cheaper, easier to produce, and less resource requiring Ju88 design we proposed. It would have much more survivability without escort due to its high speed, assuming it only uses its internal bomb bay, so less losses in 1940-41. What would be its best use then once France is beaten and we know the BoB is pointless?

 

[DonL]

You don't realy want to built this bomber without any ETC'S?
To my opinion such a fast bomber must also be able to carry 3000kg with the racks (ETC's), alone to have the flexibility.

1. Should this version be the only version till a nightfighter, or do you also want a normal Ju 88 with 55 degree dive capacity?
2. From where should come the engines for the Heinkel 111? At 1939/40 the He 111 was flieing DB 601.

 

[wiking85]

You don't realy want to built this bomber without any ETC'S?
To my opinion such a fast bomber must also be able to carry 3000kg with the racks (ETC's), alone to have the flexibility.

IMHO the Ju88 was a specialist airframe and shouldn't carry anything externally except for a fighter-bomber version like the Mosquito. Otherwise a medium bomber like the He111 or Do217 should be carrying the heavy loads; if you are taking on 3000kg externally for the Ju88 then it has to be structurally strengthened even more, which adds more weight, which means less range and speed, thus compromising the design. Its not worth it, because the Ju88's main selling point is its speed; once that is compromised it loses its purpose and its job can be done better by a slower medium bomber with more armor and defensive guns and carry a heavier load further.

1. Should this version be the only version till a nightfighter, or do you also want a normal Ju 88 with 55 degree dive capacity?

I'm totally against a dive bombing version. This version is a speed bomber, recon aircraft, nightfighter/intruder, and perhaps gunship. It was too big to reliably dive, which is why it was restricted to glide bombing early on (55 degree attacks).

2. From where should come the engines for the Heinkel 111? At 1939/40 the He 111 was flieing DB 601.

The He111 was mostly using the Jumo 211 as of March 1939 when the H-series (Jumo engined) was ready. The DB series, which was very small, the P-series, was ready earlier due to the better DB performance, but there were just too few engine available. IIRC by September 1939 only 400 engines a month were being produced from all factories; a year earlier it was even less. Meanwhile Jumo had triple or quadruple the number of engines.


BTW as an aside I'm wondering why DB never tried to go the Jumo route and work on a smaller DB that used higher RPMs. The DB605 was bigger and though it used a similar cooling system and ran with higher RPM it was only equivalent to the Jumo 211J in terms of output. AFAIK the 605 never broke the 1500hp mark.
So perhaps instead of a DB603, which we agree is problematic, why not go for a Daimler Benz version of the Jumo 213?

 

[DonL]

THe He 111 H was built after or during BoB with Jumo engines.
Not any He 111 was built 1939 with Jumo engines.

After my plan this is impossible

I need also the fast Ju 88 with racks (ETC's) to carry bigger bomb loads till the Do 217 is in service and to my opinion a dive version till 55 degree is needed for a maritim strike aircraft. The LW need especially at 1940-1942 a maritim strike aircraft for the, Atlantic (from France), Mediterranean Sea, Channel and North Sea.

Also to my plan I have the Fw 187 and Do 215 (stop gap nightfighter), there is not any single room to enlarge any other production capacity of a/c's and especially engines, because to my plan I have already enlarged Genshagen beginning 1939

 

[wiking85]

https://en.wikipedia.org/wiki/Heinkel_He_111

The H variant of the He 111 series was more widely produced and saw more action during World War II than any other Heinkel variant. Owing to the uncertainty surrounding the delivery and availability of the DB 601 engines, Heinkel began tests with the 820 kW (1,100 hp) Junkers Jumo 211 powerplants. The somewhat larger size and greater weight of the Jumo 211 engines were unimportant considerations for a twin engine design, and the Jumo was used on almost all early-war bomber designs. When the Jumo was fitted to the P model it became the He 111 H.

The He 111 H-1 was fitted with a standard set of three 7.92 mm (.312 in) MG 15s and eight SC 250 250 kg (550 lb) or 32 SC 50 50 kg (110 lb) bombs. The same armament was used in the H-2 which started production in August 1939.[47] The P-series was gradually replaced on the eve of war with the new the H-2, powered by improved Jumo 211 A-3 engines of 820 kW (1,100 hp).[47] A count on 2 September 1939 revealed that the Luftwaffe had a total of 787 He 111s in service, with 705 combat ready, including 400 H-1 and H-2s that had been produced in a mere four months.[48] Production of the H-3, powered by the 895 kW (1,200 hp) Jumo 211 D-1, began in October 1939. The experiences during the Polish Campaign led to an increase in defensive armament. MG 17s were fitted whenever possible and the number of machine guns was increased to seven. Normally one MG 17 would be installed in the nose, one in the ventral position, dorsal position and one in each waist window position. The two waist positions received an additional MG 15 or 17. On some Heinkels a permanent belt-fed MG 17 was installed in the tail.[47]

After the Battle of Britain, smaller scale production of the H-4s began. The H-4 was virtually identical to the He 111 P-4 with the DB 600s swapped for the Jumo 211D-1s.[49] This variant also differed from the H-3 in that it could either carry 2,000 kg (4,410 lb) of bombs internally or mount one or two external racks to carry one 1,800 kg (3,970 lb) or two 1,000 kg (2,210 lb) bombs. As these external racks blocked the internal bomb bay doors, a combination of internal and external storage was not possible. A PVR 1006L bomb rack was fitted externally and a 835 L (221 US gal) tank added. The PVR 1006L was capable of carrying a SC 1000 1,000 kg (2,210 lb) bomb. Some H-4s had their PVC racks modified to drop torpedoes.[49] Later modifications enabled the PVC 1006 to carry a 2,500 kg (5,510 lb) "Max" bomb. But 1,000 kg (2,200 lb) "Hermann" or 1,800 kg (3,970 lb) "Satans" were used more widely.[50]

I have multiple books, including specialist books on the He111, that confirm this. The Ju88 as a naval bomber was a bust; the He111 level and torpedo bomber was much more useful. The trick is getting the Italian aerial torpedo into production pre-war, which is very easy considering the KM held the license to do so since 1938!

 

[DonL]

I have also several books and the engl. wiki articel is wrong from the timeline!

The He 111 P series was with DB 601 engines and this engine wasn't deliverable until December 1938/January 1939, that are the same month were the Me 110 and Bf 109 started with the production. And now the englisch wiki want to tell me that next to the 834 P series also 400 H series were built at 1939?
This is wrong!
The Jumo 211 was at the beginning exclusive for the Ju 87 and Ju 88 and not until enough were produced, it was also delvered to Heinkel. The timeline from the english wiki is wrong.

I totaly disagree with your analyse about the Ju 88 as maritim strike aircraft, also the Ju 88 was equiped with torpedos. The Ju 88 was the a/c what was most dangerous at Malta beginning 1941 and at Kreta 1941 to the english navy.
The He 111 was ok but far away from the performance of the Ju 88 with it's possibility to dive.

The trick is to do more research and funding for the F5B before the war. The whole funding between 1936-1940 was 100000 RM for a Aircraft Torpedo, this was one of the biggest jokes and mistakes. Not until Tarent has shown what was possible, the funding was massively increased.

 

[Shortround6]

BTW as an aside I'm wondering why DB never tried to go the Jumo route and work on a smaller DB that used higher RPMs. The DB605 was bigger and though it used a similar cooling system and ran with higher RPM it was only equivalent to the Jumo 211J in terms of output. AFAIK the 605 never broke the 1500hp mark.
So perhaps instead of a DB603, which we agree is problematic, why not go for a Daimler Benz version of the Jumo 213?

We have said this before many times but it seems to need repeating.

When you increase the rpm the stress on the crankshaft and reciprocating parts and the crankcase go up with the square of the speed. going from 2200rpm to 2700 rpm increases the stress loads by 50%. You need a stronger crank, stronger con rods, stronger pistons, a stronger crankcase to keep things from flexing and better bearings. Friction also goes up with the square of the speed so you have 50% more power lost to friction. Not a really big deal but you don't get 22.7% increase in power you think are going ot get from the RPM increase

Going from 2400rpm to 3200rpm increases these loads by 77%.

The higher the RPM the more problems you can run into with vibration, especially harmonic vibration.

 

[wiking85]

I have also several books and the engl. wiki articel is wrong from the timeline!

The He 111 P series was with DB 601 engines and this engine wasn't deliverable until December 1938/January 1939, that are the same month were the Me 110 and Bf 109 started with the production. And now the englisch wiki want to tell me that next to the 834 P series also 400 H series were built at 1939?
This is wrong!

That's not what the article is saying at all; it is including all other previous types of He111 prior to the H and P series as well, which were still in service. A DB600 naval series for instance was produced, not to mention the lower performing pre-DB601 and Jumo 211 engine equipped series.

The Jumo 211 was at the beginning exclusive for the Ju 87 and Ju 88 and not until enough were produced, it was also delvered to Heinkel. The timeline from the english wiki is wrong.

Source on that? I have a book on the He111 that confirms the wikipedia article:
Heinkel He 111 (Black Cross, Vol. 4): Amazon.co.uk: Karl-Heinz Regnat, Regnat Karl-Heinz: Books
The author also produces RLM and Heinkel documents showing this too.

I totaly disagree with your analyse about the Ju 88 as maritim strike aircraft, also the Ju 88 was equiped with torpedos. The Ju 88 was the a/c what was most dangerous at Malta beginning 1941 and at Kreta 1941 to the english navy.
The He 111 was ok but far away from the performance of the Ju 88 with it's possibility to dive.

The trick is to do more research and funding for the F5B before the war. The whole funding between 1936-1940 was 100000 RM for a Aircraft Torpedo, this was one of the biggest jokes and mistakes. Not until Tarent has shown what was possible, the funding was massively increased.

Luftwaffe Aerial Torpedo Aircraft and Operations in World War II: Harold Thiele: 9781902109428: Amazon.com: Books
The Luftwaffe and the War at Sea 1939-1945: As Seen by Officers of the Kriegsmarine and Luftwaffe: David C Isby: 9781861762566: Amazon.com: Books
Sea Eagles: Luftwaffe Anti-Shipping Units 1939-1941 (Luftwaffe Colours): Chris Goss: 9781903223550: Amazon.com: Books
Sea Eagles Volume Two: Luftwaffe Anti-Shipping Units 1942-45 (Luftwaffe Colours): Chris Goss: 9781903223567: Amazon.com: Books

These books confirm that the He111 was preferred for torpedo operations and level bombing due to its lower wing loading and low speed performance, which was critical for torpedo drops, as they could only be dropped at around 200mph, which was pretty low for the Ju88, especially this faster one we mention here. Also the dropping aircraft needs to maneuver pretty quick to get away from defensive fire of the attacked ship, which the bigger wings of the He111 work best at.

As to your claim that the Ju88 was the most dangerous, how many He111s were there? In 1940 the He111 was the most dangerous during Norway and again during the Arctic convoy campaign.

 

[wiking85]

We have said this before many times but it seems to need repeating.

When you increase the rpm the stress on the crankshaft and reciprocating parts and the crankcase go up with the square of the speed. going from 2200rpm to 2700 rpm increases the stress loads by 50%. You need a stronger crank, stronger con rods, stronger pistons, a stronger crankcase to keep things from flexing and better bearings. Friction also goes up with the square of the speed so you have 50% more power lost to friction. Not a really big deal but you don't get 22.7% increase in power you think are going ot get from the RPM increase

Going from 2400rpm to 3200rpm increases these loads by 77%.

The higher the RPM the more problems you can run into with vibration, especially harmonic vibration.

I understand your point, yet the DB603 has serious issues as well; we know the Jumo 213 was more reliable in terms of time between overhauls and just as powerful with slightly less fuel consumption than the 603. I'm not saying its a panacea option, but perhaps given that DB was skittish about getting too involved in further aero-engine and required more investment than Jumo in terms of factories to have it just focus on improving the DB601/5 instead of focusing on multiple projects or even just the DB603. All engineering talent focused on the DB601 from 1936 on with no investment in any other DB engine is also a potential viable path.

 

[tomo pauk]

The DB 605A beat the 1500 PS mark already in late 1943, when the ban on Notleistung was lifted. See the chart here (scroll to the bottom) - 1500+something was rating at 2.1 km. The later AM and ASM versions got to 1800 PS, the 605D even to 2000 PS in case both C3 and MW-50 were available.
The DB-605 have had the displacement of 35.7 L, vs. 35 L for the Jumo 211/213. Seems not enough difference to debate about? About the high RPM capabilities of the Jumo 213 - that came with a price. The price was weight gain of some 30% vs the 211, so the Jumo 213 weights as much as the DB-603 of 44L of displacement. Another price tag, this one much more serious, was in timing - the engine was almost too late to matter for the ww2, especially the powerful two stage variants.

Maybe the LW in sea combats would've been far better served with 500-2000 kg bomb used in skip bombimg, or maybe with mast-height bombing, than to go for a torpedo? One can do skip bombing even with Bf-109 or P-39, let alone with Fw-190, Hellcat or Mosquito.

 

[wiking85]

My understanding was the 1800-2000hp was the result of engaging MW boost rather than standard power.

 

[tomo pauk]

Of course. There is no such thing as a free lunch.

 

[wiking85]

Of course. There is no such thing as a free lunch.

That's my point, Daimler did not produce a base 1750hp with the DB605. They could have done something like the Jumo 213 and gotten a heavier engine with higher base rpm rather than going the 603 route of high displacement. The 603 potentially offers an earlier high hp option, but so too could the DB605 if modded like the Jumo 213 by 1942, which is the predicted 'ready' date of the 603 anyway.

 

[Denniss]

William Green's Warplanes of the Third Reich mentions being able to fit 2x 250kg bombs in addition to the 50kgers.

Lot of BS in this book, should I mention MG 151 as cowl gun in the Bf 109K?

 

[rinkol]

BTW as an aside I'm wondering why DB never tried to go the Jumo route and work on a smaller DB that used higher RPMs. The DB605 was bigger and though it used a similar cooling system and ran with higher RPM it was only equivalent to the Jumo 211J in terms of output. AFAIK the 605 never broke the 1500hp mark.
So perhaps instead of a DB603, which we agree is problematic, why not go for a Daimler Benz version of the Jumo 213?

I think lubrication was a weakness of the DB 605. Unlike Rolls Royce or Junkers, DB never went to arrangements where oil was pumped through the crankshaft. AFAIK, the Junkers 211 series engines did not have bearing problems to the same extent as the DB605.

 

[tomo pauk]

Wiking85 said:

That's my point, Daimler did not produce a base 1750hp with the DB605. They could have done something like the Jumo 213 and gotten a heavier engine with higher base rpm rather than going the 603 route of high displacement. The 603 potentially offers an earlier high hp option, but so too could the DB605 if modded like the Jumo 213 by 1942, which is the predicted 'ready' date of the 603 anyway.

They might, but, with DB-603 in the pipeline, one might say why bother? As you may now, the next-gen DB (for 1942 on) for my LW would be the two stage engine, not the high RPM engine The DB-601 derivative weighting 2000 lbs dry would be a lousy match for the main costumer of the DB-601/605 line, the Bf-109.

added: the manual for the Ju-88 notes only 50 kg bombs in bomb bay to be carried

 

[Shortround6]

The DB 605 was pretty much useless as a bomber engine (or heavy aircraft engine) once you get past the 1475-1500 Mark. Much like some of the late war Merlins while the PEAK 1-5 minute ratings went up, the climb and max cruise ratings did not.

You need the 603 or Jumo 213 for the higher climb and cruise ratings and the fact they can use the higher power levels without needed additional maintenance or affecting overhaul life, like using water injection?MW 50 or over boosting bring on.

Please note that R-R never changed the RPM of either the Merlin or Griffon, They were able to use increased boost pressure instead. An option not really open to the Germans or at least not to the extent it was to the British due to fuel.

Do not really compare simple RPM, Piston speed is the more accurate comparison of the strain on bearings and corrected piston speed is even better. Corrected Piston speed is the piston speed divided by the square root of stroke/bore ratio. Under square engines get the number reduced and over square ones get it raised to account for the bigger (heavier) pistons.

For example the Merlin is 3000fpm ( 6in stoke X 2 for every revolution) but is corrected to the sr. rt. of 6/5.4 x 3000 for 2846.

A DB 605 at 2700rpm is 2835fpm but is corrected to 2782

A DB 603 at 2700rpm is 3190fpm but is corrected to 3026

A Jumo 213 at 3250rpm is 3520fpm but is corrected to 3200.

These are theoretical numbers and in actuality would be affected by actual piston and con rod weight as opposed to a "correction" factor but help explain why certain engines were limited to certain rpms without major changes. Allison required a new crankshaft with bigger counter weights that weighed 27lbs more than the old crankshaft to go from 3000 rpm to 3200 rpm, it would fit in the old crankcases though for even more crankshaft life. Some engines did not have extra room in the crankcase.

 

[wiking85]

The DB 605 was pretty much useless as a bomber engine (or heavy aircraft engine) once you get past the 1475-1500 Mark. Much like some of the late war Merlins while the PEAK 1-5 minute ratings went up, the climb and max cruise ratings did not.

You need the 603 or Jumo 213 for the higher climb and cruise ratings and the fact they can use the higher power levels without needed additional maintenance or affecting overhaul life, like using water injection?MW 50 or over boosting bring on.

Please note that R-R never changed the RPM of either the Merlin or Griffon, They were able to use increased boost pressure instead. An option not really open to the Germans or at least not to the extent it was to the British due to fuel.

Do not really compare simple RPM, Piston speed is the more accurate comparison of the strain on bearings and corrected piston speed is even better. Corrected Piston speed is the piston speed divided by the square root of stroke/bore ratio. Under square engines get the number reduced and over square ones get it raised to account for the bigger (heavier) pistons.

For example the Merlin is 3000fpm ( 6in stoke X 2 for every revolution) but is corrected to the sr. rt. of 6/5.4 x 3000 for 2846.

A DB 605 at 2700rpm is 2835fpm but is corrected to 2782

A DB 603 at 2700rpm is 3190fpm but is corrected to 3026

A Jumo 213 at 3250rpm is 3520fpm but is corrected to 3200.

These are theoretical numbers and in actuality would be affected by actual piston and con rod weight as opposed to a "correction" factor but help explain why certain engines were limited to certain rpms without major changes. Allison required a new crankshaft with bigger counter weights that weighed 27lbs more than the old crankshaft to go from 3000 rpm to 3200 rpm, it would fit in the old crankcases though for even more crankshaft life. Some engines did not have extra room in the crankcase.

Fair enough. Thanks for the explanation. All I'm saying is the 213 and 211 had the same displacement, which was also the same as the 605. Theoretically it was possible to go the 213 route with a DB engine, but given the limited engineering capabilities of Daimler for aero engines compared to the Jumo it makes sense why they didn't. Having the DB603 probably would result in an earlier production engine of a high output aero engine rather than redesigning the DB601/5.

 

[Shortround6]

DB probably had as much or more engineering capability in total, it's just that it was scattered all over the place. They not only had well over a dozen aircraft engine projects but naval MTB engine projects, tank engine projects and car/truck engines.