Strategies for defense 1944-45

[parsifal]

If the LW fighters engage the escorts, then they are not engaging the bombers. And they might inflict losses on the allied fighters, but the vast industrial base of the US will replace them (pilot and aircraft) quickly.

The LW would take its losses too, but they could not replace the pilots, so the battle of attrition continues.

I see no advantage to the LW by going after the escorts or evading them to concentrate on the bombers. One way or another, they're going to be in terminal decline. The only way to inflict huge losses on the US bombers would to husband their forces and attack when they can have several hundred fighters in the air at one time. And that means being grounded for weeks at a time, till the its time to strike.

The reason why going after the fighters might be better than going after the bombers is because the bombers will take longer to have any effect on the German war effort, whilst the US fighters were having a more immediate impact by shooting the flying elements of the LW out of the sky. Also, by not attacking the fighters, the skills base of the US fighters was improving, whilst the skills base of the German fighter forces was shrinking.

The weakness of this theory is that ther is no telling just how catastrophic an unimpeded bomber attack might be. The german economy in 1944 lurched from one near crisis to the next, as the cumulative effects of bombing took their toll.....eg, a hydogentaion plant might be repaired, and back on line, but much of the infrastructure that makes up the plant might be leaky and not very effieicnt as a result of the bombing. If the bombers are left unnaddressed, because the fighters are going after the escorts, one cant be sure that the better results by the bombers isnt enough to cause catastrophic effects on the targets

 

[drgondog]

No not irrelevant, because they might attain local superiority over escorts the escorts will not be the focus, interceptors tasked with intercepting the bombers are easy prey for the escorts.

Interceptors who have numerical superiority have a choice - engage or evade. The LW controllers vectored superior forces to a weak spot to a.) overwhelm the escorts to enable a strong force at attack the bombers.

Interceptors tasked with intercepting the bombers, when confronted with escorts must make one of three decisions - fight the escorts, attack the bombers and 'evade the fighters' -losing all initiative - or simply dive away.

It was more sensible evading the fighters than fighting them, that was precisely what the allies wanted. This is what the advantage of the jets was, they could ignore the escorts with near impunity and down bombers.

Actually Doolittle was described by more than one or two of his wing commanders as a 'murderer' for unleashing 8th AF FC to aggressively pursue the Luftwaffe in air or on the ground. Spaatz and Doolittle WANTED to Luftwaffe to stay and fight the fighters and the 8th BC assumed the role of aggressive bait.

'Stay away and we will proceed unmolested, stay and fight and we will grind away and win the attrition battle"

This thread is about strategies in which the LW could have had better results in 1943 and 1944 with the assets on hand. Taking away aggressive and flexible tactics from their fighter commanders was STUPID.

It is a lot easier to survive making head on attacks than it is to dive away and put a faster fighter on your tail in a tactically superior position - namely your six.

'Running and hiding' did no real good. The 109s and 190s were out dived, and shot up from behind when their best chance of survival was manuevering engagement.

maybe the average LW pilot lived longer by evading - but a.) they shot down fewer bombers that way, and b.) they gave up all initiative - giving USAAF fighter pilots the complete stage to attack, attack, attack.

If you believe the LW made the right decisions to flee in late 1943 up to the Invasion you are free to hold that opinion but I disagree! The LW remained the equal to near equal of USSR in the east with far fewer resources. They didn't 'run' there. The same super successful fighter pilots in the East struggled in the west. Why?

 

[HellToupee]

Spaatz and Doolittle WANTED to Luftwaffe to stay and fight the fighters and the 8th BC assumed the role of aggressive bait.

Thats want i said, allies wanted them to stay and fight interceptors.

If you believe the LW made the right decisions to flee in late 1943 up to the Invasion you are free to hold that opinion but I disagree! The LW remained the equal to near equal of USSR in the east with far fewer resources. They didn't 'run' there. The same super successful fighter pilots in the East struggled in the west. Why?

Ild say it was down more to the completely different tactics employed, training of soviet pilots was also not improved on until after kursk. They were not fighting a strategic bomber campaign but a tactical one and they were reduced to being able to only deal with hot spots of activity where VVS could operate on the whole front.

Most these bomber interceptors were just not fit to deal with fighters, loaded with weapons armor rockets, gun gondolas etc, their best option was just to evade and only untill much later did the escorts actually start following their back to their bases.

Escorts always held initiative over bomber interceptors.

 

[syscom3]

Parsifal, the USSBS indicated that the 8th AF didn't have much of an impact on the German war economy until summer 1944 when the oil offensive began in earnest.

Until then, the major contribution of the heavy bombers was to attract the attention of the LW fighters so as they could be shot down by the P51's and P38's.

 

[parsifal]

Parsifal, the USSBS indicated that the 8th AF didn't have much of an impact on the German war economy until summer 1944 when the oil offensive began in earnest.

Until then, the major contribution of the heavy bombers was to attract the attention of the LW fighters so as they could be shot down by the P51's and P38's.

The Bomber offensive is estimated o have affected german war production by about 10% in 1943, and somewhere between 30-40% in 1944. As you say the main impact was in the oil sector, but there were also impacts in the transport and rolling stock sectors as well.

But perhaps the greates impact was the mere fact that the germans were forced to divert increasingly large proportions of their military budgets to home defences. For example in 1944, about 25% of the total Reich defence budget was being spent on flak and its ammunition supply, another 25% was being spent on fighters, nearly all of which was being spent on Reich Fighter Defences. thats a massive proportion of the total budget.

So too was the budget being poured into the Allied Bomber offensive, but they could afford it, whereas the LW could not. Ample reserves existed in the Allied air assets to amply support the Allied armies tactically, which was not the case for the Germans.....their air force at the front was virtually disappeared by 1944 (except perhaps on the eastern Front), moreover the allies still had enough resource capacity to build a sizable naval air arm and coastal patrol force, as well as a massive transport fleet, AND a huge training establishment

 

[Kurfürst]

Yes, and the figures show an increase in strength for June.

But June was a quiet month. Murray gives German fighter losses on the East, West and Mediterranean fronts as 373.

In July the losses soared to 782. In August 531 and September 542.

Compare those with the strength figures and you'll see there was a huge drop in July, a slight improvement in August and a slight drop again in September.

Every source I have seen agrees on this, that German aircraft production was inadequate to meet the needs of the Luftwaffe for most of the war.

Nonsense.

If, according to your loss figures, fighter losses were 782 in July, and production production was 1050, 531 in August while production was 914, 542 in September while production was 853, then how on Earth was the aircraft production 'inadequate'..?

In these three months 1855 fighter losses would occur, while production amounted to 2817..

Not only the production was more than sufficient to outweight losses, it would also enable 1000 fighter aircraft to be put in reserve or to other uses (training for example, or ceded to Axis allies).

From Murray:

... SNIP ...

The problem is, that neither Murray's (he is wishful and sometimes purely rhetoric anyway) nor your conclusions is supported by the actual loss vs production data. Production far exceeded losses in every month, and was even sufficient to create sizeable reserves. This is a simple fact that cannot be argued or contested.

I guess the logical error both on you and Murray's side is that the conclusion is drawn while ignoring the relation of loss and production numbers, and solely concentrating on the fluctuation of reported strenght, (wrongly) assuming it occured because there were not enough aircraft in storage to make it up, ignoring that there was a myriad of other reasons while this strenght could change up and down, especially if the analysis is limited to a single arm (daylight fighters), while the strenght reports of other related units to which aircraft could be transferred (for example FW 190s were widely used by ground attack units, Bf 109s by recce units) are ignored, as well any other possibilities for the phenomenon.

But, as shown, the notion that production was inadequate to make for losses is not supported by the production and loss figures. Production far exceeded losses.

The reason for the fluctuation of aircraft need to be found elsewhere.

It wasn't until late in the war that production was adequate for the Luftwaffe's needs, and even then I suspect production was inadequate, it's just that lack of fuel and pilots meant the Luftwaffe couldn't use all the fighters that were being produced.

I wonder on what this suspicion is based on; for example, on 1st December 1943 the LW daylight fighters and associated OTUs report 1936 fighter aircraft; six months later, on 1st June 1944 - after some very heavy fighting in the air - they still report 1957; 1st of September this falls to 1832, but begins a massive expansion during the month, and 30 days later there are 2274 fighters with 1st and 2nd line fighter units; on 1st December 1944, they report 3715 (yes, almost four thousend).

Note and disclaimer: this post was written in pre-coffeine state.

 

[KrazyKraut]

The bypass ratio was fairly small, the fan is only a couple of inches in height. For subsonic aircraft, the greater thrust and propulsive efficiency more than makes up for the increase in drag due to greater size. With greater speed this decreases so you have low bypass jets pure jets optimised for M1+ and M2+

I don't have a figure for the diameter but judging from my photos, the F3 is about 45" diameter, pretty similar to the centrifugal types which had no real problems fitting in Meteor nacelles. Weight was 2300lb and gave 4600lbf.

Interesting. I have found very little information about these early turbofans, what eventually happened with them?.

Turbine Entry Temperature or TIT, turbine inlet temperature.

Ah okay that makes sense now.

Things are more complicated than they seem. The J79 had variable angle stator vanes so you could adjust the pr and ease starting problems. Its not simple though. The 004H had two spools, like a lot of other paper engines. Power Jets were building the LR1 turbofan with two spools. Realistically you're creating something that is more complicated and requires more maintenance, for which its probably not worth it.

Disagree here. The 004H would've been the best and fastest solution for the next generation of single engined jet fighters like the Messerschmitt prototype or the Ta 183.

Do you mean pressure ratio, not surge?

I guess i do, when it comes to these technical terms, my English sucks.

Peak efficiency for a centrifugal single stage compressor is around 4.0 and 80%, which was achieved with these early engines. The Dart with a higher pr of 5.5ish went to two stage because its more efficient for that pr. For increased performance, the axial types can be better. The advantage the centrifugals have is simplicity and reliability.

No argument here.

You run into problems with the blade stress increases, being more prone to surge with the increased pr, greater Mach number reducing efficiency. Its not a matter of "simply" at all.

You run into problems no matter what. That's part of development. It certainly is a lot easier though to keep the basic layout and a certain percentage of components than it is to built and entirely new engine.

Was it best for what was needed at the time? No, which is why single spool turbojets and centrifugal types still dominate the low end of the market. Its only when you need greater thrust and lower fuel consumption (other factors as well) that more spools are useful. For the long range big jets the three spool Trent reigns supreme in terms of performance, but its not designed and built in the US so only has 40% of the market.

Which is why the Jumo 004 or BMW 003 were the best choices for a twin engined fighter at that time. Once you went to single engined fighters, things change. And with the Jumo 004H you could get a sufficiently powerful jet with relative (again relative is the keyword here) ease.

Lots of people had the same ideas, but Whittle's simple engine worked reliably despite offering lower performance. The most advanced engine would be Griffith's CR.1 contrafan with a high bypass ratio fan, high pr and novel 32 individual spool design for maximum off peak performance, but it didn't work with the technology of the time.

If advanced means overly complex, yes. Not even practical today.

 

[HellToupee]

Which is why the Jumo 004 or BMW 003 were the best choices for a twin engined fighter at that time. Once you went to single engined fighters, things change. And with the Jumo 004H you could get a sufficiently powerful jet with relative (again relative is the keyword here) ease.

They never got the Jumo 004a working all that well, ild hate to see a 004h, the Russians persued developing the jumo post war and ultimately gave up.

 

[FLYBOYJ]

They never got the Jumo 004a working all that well, ild hate to see a 004h, the Russians persued developing the jumo post war and ultimately gave up.

The only reason why there were "problems" with the 004a was because of raw materials and the condition some of these engines were assembled in, and credit to the Germans, they were coming up with "workarounds" to get these engines produced and made more reliable. As far as the Russians "giving up" on this engine, can you explain where the RD-10 came from? It powered the Yak-15 and -17, and while neither one of them were raging successes it did give the Soviet Union the platform to eventually develop more successful centrifugal engines (RD-9).

Then in the middle of this they (the Russians) were handed a Nene, so where do you think the focus went to, at least for a short period?

BTW the 004 was also used by the French to power some of their first jets after the war, right now their names escapes me.

 

[Juha]

Hello Kurfürst
in fact it's you who made the biggest logical error, you compared 109 and 190 production to fighter losses and drew conclusion that production was more than adequate while you acknowledged that also ground attack and recon units used the types. Until you added losses of those units to equation you will draw too optimistic conclusion.

Was German fighter production adequate? At least in 1943 and first half of 44, no. If the quantity and quality of planes and/or pilots had been adequate, fighter arm of LW would has been capable to give reasonable protection to Heer and would has been able to protect German industry and especially factories which produced essential war materials and fuel production plants. Because it could not there was something fundamentally wrong in Jagdwaffe, in quantity and/or in quality.

I can also claim that this message was written in pre-coffeine state, I didn't have time any coffee-brake today.

Juha

 

[Kurfürst]

Hi Juha,

Thank you for the usual uninformative partisan post, it is nothing new from you. Keep repeating the same biased preconceptions of yours, without any evidence offered.
It is what you do best, after all.

 

[parsifal]

I think its arguable either way as to whether the supply of aircraft was adequate to keep up with losses. But what is definately the case is that this was not the major constraint affecting the frontline, operational strength of the Luftwaffe. The two major issues were, firstly the numbers of properly trained pilots, and secondly the supply of fuel.

In the first instance (pilot supply) the Germans were only able to keep their frontline strength up by increasingly vicious combouts of the training schools. This was so bad that by the end of 1944, the average training time had fallen to below 100 hours for you garden variety LW pilot. By comparison the US pilot training was powering on, I believe the average training time was by that time something like 600-700 hours.

Small wonder then that the US fighters were shooting down 5 o6 LW fighters for every escort lost by the end of the war.

The second issue that affected the German readiness rates was fuel. This I believe managed to keep large slabs of the LW fighter forces grounded as the war progressed. For example, at the very end of the war, I believe there were about 2000 fighters on the eastern front, but during the Soviet offensive across the oder, the germans were only able to keep about 100 of these operational, due to fuel and logistical problems.

What I dont get though is that as far as I know, there was not a vast stash of fighters captured at the end of the war....or was there. If I am correct, what happened to all this alleged excess production???

 

[Juha]

Hello Kurfürst
now it's funny to see you blaiming that others are biased. Now on evidence, 109 and 190 losses of ground attack units can be find from Michael's pages, you already gave the link.

On the inadequate of Jagdwaffe was clearly seen during in spring 43 over Tunisia and over supply routes there, during summer 43 over Sicily, then over Italy and then over ETO, in summer 44 over both Western and Eastern front. And in 43 it was mainly on question of inadequate numbers, later on the most important single factor IMHO was too hasty trained new pilots.

Juha

 

[red admiral]

I have found very little information about these early turbofans, what eventually happened with them?

There isn't a great deal available. The Metrovick F3 survives in the Rolls Royce Heritage trust at Derby. I'm told the open fan section of the F5 is around somewhere, I think it might be Manchester Museum of Science and Industry or maybe Cranwell.

The 004H would've been the best and fastest solution for the next generation of single engined jet fighters

Probably a step too long with first engines unlikely to be around for a few years. Easier to try and make HeS011 work well (maybe another 6months+) or improve existing 003 and 004.

It certainly is a lot easier though to keep the basic layout and a certain percentage of components than it is to built and entirely new engine.

Today when development takes so long and cost so much yes (e.g. RR Trent's 3-spool adaptability) but when you can hammer out a new engine like the Nene in 5 months... The new technology was progressing so fast that it was much more beneficial to design from new. Still you can build on previous research e.g. the AS Sapphire coming from the RAE's extensive research in the 30s and early 40s with the Metrovick engines and AS's own gas turbines.

Which is why the Jumo 004 or BMW 003 were the best choices for a twin engined fighter at that time. Once you went to single engined fighters, things change. And with the Jumo 004H you could get a sufficiently powerful jet with relative (again relative is the keyword here) ease.

Personally I think the centrifugal was a better choice for the time period. Lots of the research already done so the focus is on productionising and improvements. Easy to scale each way from a successful design. e.g. Nene scaled down to give Derwent V and scaled up to give VK-1.

If advanced means overly complex, yes. Not even practical today.

Its more the search for the ultimate in performance, which is relatively easy in a jet engine as you can calculate performance better than measuring it. The simplicity and reliability of the centrifugal won the day. It would be interesting to reexamine Griffith's contrafan today and see if it could be made to work better. Tighter tolerances possible with ECM would probably make quite a jump.

The only reason why there were "problems" with the 004a was because of raw materials and the condition some of these engines were assembled in

Raw materials weren't really a problem for the 004A and get a lot of unjust stick. Better heat resistant alloys improve turbine lifetime they don't magically make all the other problems disappear. Compressor surging, combustion problems and harmonic excitation won't magically disappear are are far greater problems. Build quality is rather poor on the 004B engine at RAF Cosford compared to the Derwent and Goblin on display.

The French and Russian's used the 004 as is because it was available. As soon as better engines were available it was discarded. The design of the 004 itself died and didn't really lead to anything. The Russian axial program was already extant and the Atar took a very long, convoluted path from the 003.

 

[davebender]

There was nothing wrong with the Luftwaffe pilot training program per se. There simply wasn't enough fuel to go around.

 

[Kurfürst]

Hello Kurfürst
now it's funny to see you blaiming that others are biased. Now on evidence, 109 and 190 losses of ground attack units can be find from Michael's pages, you already gave the link.

I see. If you are claiming that German fighter production was insufficient to make up for losses, then prove it, with some actual facts.

As shown with loss and production figures already, German fighter production greatly exceeded German fighter losses in 1943. There was never any shortage of fighters planes or modern fighter planes. This sizeable excess of fighter production also enabled the Germans to build sizeable reserves of fighter aircraft, and even export some of them to their allies.

You are welcome to come up with your own production and loss sources to challenge that.

Of course, a true partisan should never offer any evidence, and would not require any either to convince himself - he knows, feels, lives and breaths the truth from the very beginning. For him, it is a kind of biological, and not rational process. A true partisan, when asked support his claims, never lowers himself to provide them, but jumps on the next claim in a most elegant manner. A true partisan is certain in the righteousness of his way - therefore, it would seem improper for him to do anything else but to repeat the same over and over again. For this reason, with firm of the knowledge that he is right, he cares little that he keeps ending up on more and more people's ignore lists, or to examine evidence himself at all - what a redundant activity, when he already knows it could only prove him right...!

But you are not such an entity, are you, Juha? Of course you are not. That is why we will see tons and tons of nice objective loss and production data in your next post, highlighting your position.

On the inadequate of Jagdwaffe was clearly seen blah blah blah blah blah....

Ah, 'clearly', I see. A bit vague isn't it..? Any particulars of your newest claims or are you merely changing your arguement, jumping to the next claim and that sort of stuff?

 

[KrazyKraut]

Probably a step too long with first engines unlikely to be around for a few years. Easier to try and make HeS011 work well (maybe another 6months+) or improve existing 003 and 004.

IIRC the HeS011 was a two spool aswell and certainly more complex overall. The 004H would've been a much more practical solution. Of course, the HeS011 was more developed when the war ended. And well, to my understanding the 004H did just that, improve on the 004.

Today when development takes so long and cost so much yes (e.g. RR Trent's 3-spool adaptability) but when you can hammer out a new engine like the Nene in 5 months... The new technology was progressing so fast that it was much more beneficial to design from new.

This line of thought is one reason why so many British developments never became operational in time. Sure the basic concept was established in short time and early prototypes follow, but the substantial time it takes to iron out bugs and set up large scale production is another story. The Jumo is a prime example for this.

Personally I think the centrifugal was a better choice for the time period. Lots of the research already done so the focus is on productionising and improvements. Easy to scale each way from a successful design. e.g. Nene scaled down to give Derwent V and scaled up to give VK-1.

I understand your point of view but disagree. As the first generation was to be driven by two engines, frontal area was an important aspect and the centrifugal compressor looses here, especially the Whittle design. Another thing that bothers me about the layout are the strict requirements to the nacelles: You easily end up with a too long air intake and lose thrust (something that is often overlooked when raw performance of the engine is compared). Other than that both designs were valid choices.

Its more the search for the ultimate in performance, which is relatively easy in a jet engine as you can calculate performance better than measuring it. The simplicity and reliability of the centrifugal won the day. It would be interesting to reexamine Griffith's contrafan today and see if it could be made to work better. Tighter tolerances possible with ECM would probably make quite a jump.

Oh contrafans are being worked on by P&W for example, though cerainly geared turbofans are the next thing. Not far away actually , I think they will enter service 2013. The multi-spool thing though, that's not going to come in another decade if ever.

Raw materials weren't really a problem for the 004A and get a lot of unjust stick. Better heat resistant alloys improve turbine lifetime they don't magically make all the other problems disappear. Compressor surging, combustion problems and harmonic excitation won't magically disappear are are far greater problems. Build quality is rather poor on the 004B engine at RAF Cosford compared to the Derwent and Goblin on display.

Build quality will be poor on any German engine that was built in 1945, no matter if jet or piston. The other "problems" were manageable. For a first-of-its-kind production engine the Jumo 004 was pretty reliable.

The French and Russian's used the 004 as is because it was available. As soon as better engines were available it was discarded. The design of the 004 itself died and didn't really lead to anything. The Russian axial program was already extant and the Atar took a very long, convoluted path from the 003.

The Russians were far behind ALL other WW2 nations at the time. That's why they were not able to significantly improve on the Jumo 004 for some time and then someone drops the fully developed Nene in their lap including all knowledge how to built them... what do you think they're going to use? To take this as an example that the Jumo was at the end of its road is wrong as the design progess essentially ended with WW2. It was rather to the luck of Oestrich that the French were able to collect the astonishing number 200 BMW + subcontractor employees so he could continue the 003 development into what became the Atar.

 

[Kurfürst]

I think its arguable either way as to whether the supply of aircraft was adequate to keep up with losses. But what is definately the case is that this was not the major constraint affecting the frontline, operational strength of the Luftwaffe. The two major issues were, firstly the numbers of properly trained pilots, and secondly the supply of fuel.

Agreed. Fuel was certainly a major limitation, as shown by the consumption-production curves of avgas. It defined the maximum number of aircraft the Germans could still supply with fuel. I pretty sure this - and pilot training programmes - was the major limitation for all other combatants as well, looking at the RAF fighter strengths, despite seeing far less intense combat than the Luftwaffe on its three fronts, it would appear that they too hit some sort of invisible barrier, otherwise the number of aircraft would far exceed that of the Luftwaffe, but from the statistics I've seen, this doesn't appear to be the case. Given that the UK was largely dependent on US supplies of high octane aviation gasoline during the war - much of it was required by Bomber Command - I suppose it was the fuel limit, again. The average monthly consumption figures for 100/130 octane avgas in the UK in 1943 for example was 115 000 tons - quite similiar to the German consumption actually, if we allow a bit for the other, less active theatres.

And then of course, there's the US, producing an unbelievable 300 000 or so aircraft during the war - but having but a fraction of that operational at any time. I guess the reasons were similiar - even US fuel reserves and shipping capacity was not bottomless.

 

[FLYBOYJ]

The Russians were far behind ALL other WW2 nations at the time. That's why they were not able to significantly improve on the Jumo 004 for some time and then someone drops the fully developed Nene in their lap including all knowledge how to built them... what do you think they're going to use? To take this as an example that the Jumo was at the end of its road is wrong as the design progess essentially ended with WW2. It was rather to the luck of Oestrich that the French were able to collect the astonishing number 200 BMW + subcontractor employees so he could continue the 003 development into what became the Atar.

Agree and also consider that considering the Soivets "gave up" on the Jumo, they shoved them into 280 Yak-15s and 430 Yak-17s.

 

[Amsel]

There was nothing wrong with the Luftwaffe pilot training program per se. There simply wasn't enough fuel to go around.

There wasn't a very good program after 1943. Many of the replacements were killed before they even knew how to properly fly their fighter. Some showing up with only a few hours in a Focke-wulf. It was very bad times for the Lw starting in 44'.