Ju 188 - why not?

[yogybär]

If I see it correctly, the Ju 188 was a much better plane then the original Ju 88. Nevertheless, the 88 was built in much higher numbers, bomber versions as well.

What are the reasons for that?

First I thought about shortage of BMW 801, but the A and D-series had Jumo engines... so what is the answer?

[Graham Boak]

I can think of five reasons.

1. It was a lot later appearing. Many Ju88s were built before there was any choice in the matter.
2. It also used the more powerful, larger, engines that were in short supply and great demand. The Jumo in the A/D was the 213 not the 211 of the Ju88A/C.
3. What could have been later production was cancelled to allow concentration on fighter production from 1944 onwards.
4. I'm not sure about this, but it is possible that the Ju88 (bomber) was retained in production alongside the Ju188 because it continued to use available engines, and because the loss of production in the changeover was considered more important than the improvement in performance.
5. The Ju188 was ruled unsuitable as a night fighter, because of its glazing. Therefore the Ju88 was retained in production as a fighter. It is fair to say that the later Ju88G was in many ways a Ju188 fighter under another name.

That's four good reasons and one debatable one.

[yogybär]

Thanks Graham.

1,3 & 5 I knew already, 4 might definitely be a good reason.

Originally Posted by Graham Boak

engines that were in short supply and great demand. The Jumo in the A/D was the 213 not the 211

==> Were 213s really less available then 211s? Wasn't the 213 was used in the Fw 190 D-9 because it was so well-available?

[Juha]

Hello
IIRC Junkers tried to get Ju88B, a sort of proto Ju 188, into production but RLM thought that improvements were too small to warrant switch, and the loss of production due it, from Ju 88A to Ju88B. And very importantly, RLM was putting very high expectations to Bomber B program, so it thought that there was no need for interim Ju 88B. Only after it was very clear, that the Bomber B program was to be a failure, RLM interested again in Ju88B. In meantime Junkers has continued the development of Ju88B as a low-priority private venture and when RLM showed interest on Ju88B it could present plans for Ju188. So the main reasons for late production of Ju88B/188 were, the need to keep medium bomber production up and the misplaced hopes to overambitious Bomber B program. RLM had not learnt that the worst enemy of good is the best.

On Jumo 213, I don’t recall its production numbers but even if there was enough of them for Fw 190D that doesn’t meant that there would have been enough for mass-producing Ju188As

Juha

[Graham Boak]

Yes, the 213 was less available than the 211, see reason 1. It was used in the Fw190D because DB603s were even less available.

I'm not sure about 4, partly because I'm not up to speed on Ju88 production lines (number and location) and partly because the two aircraft seem to have had many similar parts. Therefore changing from 88 to 188 would cause much less disruption than say from 88 to 217 (not that such was ever on!). Alternatively, there may be hidden structural differences that made the switch more awkward (time-consuming/costly) than it might appear.

I strongly suspect, however, that the production of the 188 was limited more by engine supply than any other single cause.

[Graham Boak]

Juha: I hadn't thought of it from the approach: Why wasn't the 188 put into production sooner? but I think the answer is the same. All nations underestimated the time needed to develop a new engine, and that was behind both the failure of the Bomber B programme and delays in getting the DB603/Jumo213 families available. It's easy to be too hard on the RLM - clearly progressing in simpler, less advanced, steps wasn't the right answer either. I don't think the 188 could have been brought forward too much - remember that Dornier were building bombers that were left standing out on the airfield for lack of engines.

It is very important to keep the timeline in mind - the Fw190D did not start rolling off the production lines until August 1944, too late for most of the decisions on the Ju188. The engines available in late 1944 weren't there in 1943.

[Juha]

Hello Graham
even without new engines the new cockpit and new outer wings would have bought some drag reductions and so performance increase and would have given better view and more room to the crew.

I understand well the difficulties of wartime production planning, British had their own mistakes and difficulties, which are sometimes forgotten when discussion centered on what RLM did and didn't and IMHO a small improvements, if possible without too big production losses, is better than no improvement at all while waiting a “super-plane” which never arrived. At least in Spitfire development British were wise enough to put interim designs, like Mk V, IX and XIV, fast in production when situation demanded without waiting that the proper designs, like Mk VIII and 21, were finished.

Juha

[Graham Boak]

Yet there are those who argue that the RLM was too timid in continuing to incrementally develop the Bf109 (for example) rather than be more ambitious and risk-taking. I do feel that the RLM gets the blame for everything, however contradictory that ends up.

The Ju88B did not have the extended wings which (with the engines) actually provided the improved performance. The new cockpit was good but hardly vital, the B not having the upper turret either, although the E did. And as far as the engines go, we are back in the limited supply discussion. Who gets the limited supply of BMW801s? The long-awaited new fighter? The equally awaited new medium bomber? The asymmetric army observation aircraft? The long range flying boat for the Atlantic war? Or use them for making not-that-significant improvements to what is already the best light bomber around?

I agree the British had their problems too. Not least with the supply of big engines, and the delayed appearance of new generation fighters and bombers.

[Juha]

Hello Graham
at least I don’t blame RLM on 109 development, even if there was a plateau in performance improvement between F-4 and G-6/AS, but that was more because of the problems with DB605A. I agree with you on the sometimes unreasonable harsh critics on RLM, it made its mistakes but so did the other orgs in other countries which controlled aviation development and production. Maybe Udet was a failure but under pressures of war all made mistakes.

The extended wings, you might well be right, I wrote from memory.

I agree that engines were a major problem because of need more performance for ever heavier planes and there were bottlenecks in BMW engine production. And yes, British had their fair share of engine problems, early Bristol sleeve valve radials were unreliable and generally Roy Fedden seemed to have given too little attention to supercharger performance, RR had the Vulture and Napier seemed to have mismanaged its Sabre development. All British 2000hp engines were delayed or run to too big problems producing many problems in a/c development and production.

On Ju medium bombers, IMHO something ought to be done because Allied (incl. Soviet) fighters and AA got better and because there was no meaningful advancement in Ju88 performance its survivability suffered and it lost its ability to operate daytime in MTO with reasonable lossrate, partly because the number of LW fighters was becoming too low. If more powerful engines were not available in sufficient numbers at least some aerodynamic chances should have been done.

Juha

[Nick Beale]

The Ju 88 S might also be a significant factor. It's notable in Luftwaffe reports of bomber operations (via ULTRA) that the Ju 88 and Ju 88 S are listed separately when numbers of sorties are given.

That suggests to me that the S was seen as something different from the long-serving A-model, almost as a type in its own right.