Ideal Luftwaffe starting 1/1/1936

[wiking85]

Any thoughts about a real 'Schnellbomber', ie. a fast bomber? Hopefully with close to no guns? Was the dive bombing requirement such a bugaboo?

I've been a major proponent of it on alternate history forums. It would be lighter, faster, easier to make (such as the Ju88 being delayed by modification complications in actual mass production like with its 90 degree rotating wheel to handle the modified nose to deal with diving), and less fuel consuming.
I think a German Mosquito in the form of the Ju88 with two crew and no defensive guns would be a fine aircraft and very difficult to intercept, especially if it can do shallow dives to gain speed. In fact I did a thread on that subject:
http://www.ww2aircraft.net/forum/aviation/ju88-luftwaffes-mosquito-34542.html

With increasingly powerful engines it would have been a true 'Schnellbomber'. Using the DB603 in 1942 would have turned it into a serious threat in the East, not sure about over Britain though, except at night; the Mosquito did not do well initially during the day in 1942 IIRC.

 

[tomo pauk]

Germans can do better than Ju-88. The wing area of the 88 was 25% greater than of Mosquito, A-20 or Pe-2. That means greater drag, = less speed. The annular radiator was probably a sensible choice, but 'embedded' wing radiators should earn few mph on their own. The low set wing 'steals' space for an unrestricted bomb bay. Bombs under external hard points kill performance. With high set wings, the possibility is there to carry the 1800 kg bomb as the Ju-87D was capable for. The max caliber of bombs in the Ju-88 bomb bay was 50 kg?

 

[wiking85]

Germans can do better than Ju-88. The wing area of the 88 was 25% greater than of Mosquito, A-20 or Pe-2. That means greater drag, = less speed. The annular radiator was probably a sensible choice, but 'embedded' wing radiators should earn few mph on their own. The low set wing 'steals' space for an unrestricted bomb bay. Bombs under external hard points kill performance. With high set wings, the possibility is there to carry the 1800 kg bomb as the Ju-87D was capable for. The max caliber of bombs in the Ju-88 bomb bay was 50 kg?

Which version of the Ju88? Also the wing area was expanded from the A1 to A4/5 series due to the high wing loading issue; supposedly the A4/5 wing design improved maneuverability and lift without drag penalty due to aerodynamic efficiency. All that was lost was due to increased weight, again supposedly.

I wonder how the V1 or 2 prototype of the Ju88 sans third crew member and defensive armament would have done.
https://en.wikipedia.org/wiki/Junkers_Ju_88

The first two prototypes, Ju 88 V1 and V2, differed from the V3, V4 and V5 in that the latter three models were equipped with three defensive armament positions to the rear of the cockpit, and were able to carry two 1,000 kg (2,200 lb) bombs, one under each inner wing panel.

The aircraft's first flight was made by the prototype Ju 88 V1, which bore the civil registration D-AQEN, on 21 December 1936. When it first flew, it managed about 580 km/h (360 mph) and Hermann Göring, head of the Luftwaffe was ecstatic. It was an aircraft that could finally fulfill the promise of the Schnellbomber, a high-speed bomber. The streamlined fuselage was modeled after its contemporary, the Dornier Do 17, but with fewer defensive guns because the belief still held that it could outrun late 1930s-era fighters. The fifth prototype set a 1,000 km (620 mi) closed-circuit record in March 1939, carrying a 2,000 kg (4,410 lb) payload at a speed of 517 km/h (320 mph). However, by the time Luftwaffe planners like Ernst Udet had their opportunities to their own "pet" features added (including dive-bombing by Udet), the Ju 88's top speed had dropped to around 450 km/h (280 mph)

Keep in mind this was with the Jumo 211A.

The front wheel proved very problematic, but wasn't part of the original design:

Production was delayed drastically by developmental problems. Although planned for a service introduction in 1938, the Ju 88 finally entered squadron service (with only 12 aircraft) on the first day of the attack on Poland in 1939. Production was painfully slow, with only one Ju 88 manufactured per week, as problems continually kept cropping up.

The first five prototypes had conventionally operating dual-strut leg rearwards-retracting main gear, but starting with the V6 prototype, a main gear design debuted that twisted the new, single-leg main gear strut through 90° during the retraction sequence, much like that of the American Curtiss P-40 Warhawk fighter. This feature allowed the main wheels to end up above the lower end of the strut when fully retracted [N 1] and was adopted as standard for all future production Ju 88s, and only minimally modified for the later Ju 188 and 388 developments of it. These single-leg landing gear struts also made use of stacks of conical Belleville washers inside them, as their main form of suspension for takeoffs and landings.

From the German Ju88 article about the developments of the Ju88A:
https://de.wikipedia.org/wiki/Junkers_Ju_88

Ju 88 A-1 (1940)
Wingspan : 18.25 m
Length: 14.36 m
Height: 4.85 m
Wing: 52.5 m²
Maximum speed: 460 km / h in 5500 m, without bomb load


Ju 88 A-5 (1940-1941)
Wingspan: 20,08 m, partly 19,95 m
Length: 14.36 m
Height: 4.85 m
Wing: 54.7 m²
Maximum speed: 460 km / h in 5500 m, without bomb load

Same engines and speed, larger wing area and length. Apparently the new wing design wasn't the issue. The engine upgrade came with the A4, which was after the A5. The A5 was just the early introduction of the new wing design before the new Jumo 211s were available in 1941.

Ju 88 A-4 (1941-1944) [ edit ]
Purpose: dive bomber capable
Wingspan: 20,08 m
Length: 14.36 m
Height: 4.85 m
Wing: 54.7 m²
Powerplant: two Junkers V12 engines Jumo 211 J each with 1420 hp takeoff power or two Jumo 211 F-2 with 1350 hp starting power
Top speed: 500 km / h without bomb load

The max caliber of bombs in the Ju-88 bomb bay was 50 kg?

They could take 2x 250kg bombs in the primary bomb bay, but otherwise only 50kg bombs.
I agree that the Ju88 could have been better designed, but the original design was pretty good until it was compromised by the dive bombing and extra crew/defensive armament and external bomb racks.

 

[tomo pauk]

I was referring to the 'regular' wing, like the A-4 or C-6 were outfitted with. The Ju-88A-0, and presumably prototypes (?) were outfitted with a wing that was of 5% smaller area.
This Shnellbomber should be also a fine platform for night fighter gear.

 

[wiking85]

I was referring to the 'regular' wing, like the A-4 or C-6 were outfitted with. The Ju-88A-0, and presumably prototypes (?) were outfitted with a wing that was of 5% smaller area.
This Shnellbomber should be also a fine platform for night fighter gear.

But as the numbers I showed demonstrated the greater wing area did not penalize the Ju88's speed from the A-1 to A-4/5. I agree that keeping the original wing length (not sure if the A-1 did) would be better in terms of overall weight, but it did not seem to come with a drag penalty; in that case it is in fact more in the Ju88's favor to have a larger wing to reduce landing speeds, increase maneuverability and lift in flight, and have a stronger wing in general even with the minor weight penalty.

This design without rear armament and third crew member is ideal IMHO:

 

[tomo pauk]

The wing area of the three allied bombers can be sated as 100%. The A-1 would be at 124.5% (vs Mosquito), the A-4 would be at 129.5%. In other words, the mere 4% of the increase of wing area between different Ju-88s should mean few km/h of dfference, ie. well within the production tolerances. The difference in wing area of 24.5 or 29.5% should produce a more notable speed difference.
The bigger wing of the historic Ju-88 vs. Mosquito was needed - additional crew members are weight penalty, ditto for the MGs ammo they would be using, plus one must provide a suitable accommodation for those, and that demands more volume, that again drives both weight and size up. Bigger weight size: more fuel needed. More fuel = more weight. More weight = bigger wing.
Sort of a weight creep, or weight spiral that goes up.

 

[wiking85]

The wing area of the three allied bombers can be sated as 100%. The A-1 would be at 124.5% (vs Mosquito), the A-4 would be at 129.5%. In other words, the mere 4% of the increase of wing area between different Ju-88s should mean few km/h of dfference, ie. well within the production tolerances. The difference in wing area of 24.5 or 29.5% should produce a more notable speed difference.
The bigger wing of the historic Ju-88 vs. Mosquito was needed - additional crew members are weight penalty, ditto for the MGs ammo they would be using, plus one must provide a suitable accommodation for those, and that demands more volume, that again drives both weight and size up. Bigger weight size: more fuel needed. More fuel = more weight. More weight = bigger wing.
Sort of a weight creep, or weight spiral that goes up.

Fair enough, a more speed oriented design would require less wing area. Still I wonder then how much different the V1 prototype design was from the A-1's wing. Keep in mind though that the Mosquito was also made of wood, so weighed less than the aluminum Ju88, so could afford a smaller wing. It also had a second potential bomb bay, which increased the weight vs. the Mosquito. AFAIK the A-1 wing was fine provided the weight was kept down in terms of the defensive armament, no dive modifications, and no external bomb racks. The V1 prototype of course was lighter than a production model would be due to IIRC no fitted armor or full kit out that a combat model would have. Still, even a 330mph top speed Ju88 with a cruise speed around 300 mph would be very tough to properly intercept in 1940-41. That would be with the Jumo211B engine, so having a Jumo211F or J would increase the speed nicely if all else remained the same. A later Jumo 213 or DB603 engine upgrade would also offer a major increase, provided the original design concept is kept.

 

[rinkol]

The wing area of the three allied bombers can be sated as 100%. The A-1 would be at 124.5% (vs Mosquito), the A-4 would be at 129.5%. In other words, the mere 4% of the increase of wing area between different Ju-88s should mean few km/h of dfference, ie. well within the production tolerances. The difference in wing area of 24.5 or 29.5% should produce a more notable speed difference.
The bigger wing of the historic Ju-88 vs. Mosquito was needed - additional crew members are weight penalty, ditto for the MGs ammo they would be using, plus one must provide a suitable accommodation for those, and that demands more volume, that again drives both weight and size up. Bigger weight size: more fuel needed. More fuel = more weight. More weight = bigger wing.
Sort of a weight creep, or weight spiral that goes up.

One question that arises concerns whether the Hs 127 was a missed opportunity - supposedly the prototype demonstrated an excellent performance. Unfortunately, very little information that would support a comparative assessment has survived.

 

[wiking85]

One question that arises concerns whether the Hs 127 was a missed opportunity - supposedly the prototype demonstrated an excellent performance. Unfortunately, very little information that would support a comparative assessment has survived.

https://en.wikipedia.org/wiki/Henschel_Hs_127

The maiden flight of the Hs 127 V1 was at the end of 1937. The plane was smaller and lighter than the Ju 88 and had a very good top speed of 565 km/h (353 mph), but the Ju 88 was chosen because of its bigger bomb load.

Looks pretty similar to the early Ju88 prototypes:
Ju88:

Hs127

 

[DonL]

To my opinion compromises must made.

From sources, this 50kg bomb issue, was clearly a RLM mistake, because it was an explicit requirement of the RLM advertisement of 1935.

From my own research, the fulsage of the Ju 88 had enough volume to take other internal bomb loads and bigger bombs, but the development and the sub-division of the fulsage was in 1937/38 in such an advanced stage, that you have to complete reconstruct the whole fulsage for other requirements.

It is a big hindsight that it was't changed the whole war and to me the only explanation is, that a reconstruction would take too much time and effort.
The original fulsage could take 1400kg internal bomb load

I haven't written or changed this requirement in this thread, because it was said, changes from 1936.
From all I have researched you can built a Ju 88 to the same external dimensions, but with an other sub-divisioned fulsage to take 1400-1500kg internal bomb load with 250kg or 500kg bombs.

So to me the Ju 88 is also the best design next to the Mosquito for a fast bomber.

 

[wiking85]

AFAIK the major factor in preventing a reworking of the internal bomb bays was the need to get new jigs, which was deemed too costly. The structural reworking would have been very possible, but it would have altered the production lines too much to be easily phased in. That's why the Ju188 was settled on, because it was basically keeping the Ju88 design with a new cockpit that didn't require new jigs for the majority of the aircraft.

 

[tomo pauk]

The timer starts with 1936, the 1st flight of the Ju-88 prototype was at the end of that year. We should have enough time. If not, the non-issue of dive bomb requirement should save some time, as would non-adding of new crew positions armament ammo.
We don't have any production of the Ju-88, so there is no change in production tooling.

 

[wiking85]

The timer starts with 1936, the 1st flight of the Ju-88 prototype was at the end of that year. We should have enough time. If not, the non-issue of dive bomb requirement should save some time, as would non-adding of new crew positions armament ammo.

Agreed. The prototype was still in design by 1/1/1936:
https://en.wikipedia.org/wiki/Junkers_Ju_88

Junkers presented their initial design in June 1936,

The changes in the design stage shouldn't be that big of a delay.

 

[tomo pauk]

Better rethink the wing location ASAP. A complete sentence is:

Junkers presented their initial design in June 1936, and were given clearance to build two prototypes (Werknummer 4941 and 4942).

 

[DonL]

Thank you for this post wiking, do you have a source to me for the jigs?

Also your post confirmed my opinion that the general design of the Ju 88 could do the job of a fast bomber.

Edit:

Ok then an immediately order at 1936 to my plan would be

- redesign of the Ju 88 internal fulsage to take bombs till 1000kg up internal, with the same external dimensions.

 

[wiking85]

Thank you for this post wiking, do you have a source to me for the jigs?

I do not, its a hunch given the long lead time that was mentioned about getting jigs together in "arming the luftwaffe" by Edward Homze. It was also mentioned as a reason they couldn't reproduce the Hs123 in 1944, due to the jigs being destroyed in 1940.
https://en.wikipedia.org/wiki/Henschel_Hs_123

However, the Henschel factory had already dismantled all tools and jigs in 1940.

I suppose it took a fair about of specialized design and production resources to get these ready. Homze mentions there was a 2-3 year lead time on tooling pre-war and during the early stages due to major mismanagement and too much demand on the machine tool industry, which was not as forward thinking as other countries, especially the US. Homze also claims that Germany was short some 30,000 engineers for all demands of the military services and industry.

Arguably the problem would have also been the loss in production experience and the need to scrap the specialized machine tools developed for Ju88 production that boosted output. Budrass did an article about how experience created the armaments miracle in production after 1942 and used the Ju88 and aviation industry as a model (ignoring major issues though IMHO):
http://www.econ.yale.edu/growth_pdf/cdp905.pdf

This book has some disagreement with that perspective
http://www.amazon.com/dp/0786465212/?tag=dcglabs-20

Also your post confirmed my opinion that the general design of the Ju 88 could do the job of a fast bomber.

It wasn't perfect as Tomo points out, but should be sufficient even without too much hindsight altering the original design.

 

[BiffF15]

Just think how many more types, varients, etc. of aircraft, tanks, vehicles they could have had with 30k more engineers.

Cheers,
Biff

 

[wiking85]

Just think how many more types, varients, etc. of aircraft, tanks, vehicles they could have had with 30k more engineers.

Cheers,
Biff

IIRC it was more needed in terms of testing at Rechlin, in the machine tools industry, and in repair depots behind the lines.

 

[Denniss]

Evne the forward bay in a Ju 88 could only hold 50 kg bombs, never heard or seen evidence of anything larger.

 

[wiking85]

Evne the forward bay in a Ju 88 could only hold 50 kg bombs, never heard or seen evidence of anything larger.

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