Did the Allies Just Have Better Engines?

[Admiral Beez]

Did the Allies just have better engines?

I think the Allies just had better, higher octane fuel. And access to better metals.

Put 130 octane into a Bf 109 modified for the much higher compression fuel and watch it fly. And give a Me 262 engines made of its intended alloys and metals and it will have Gloster Meteor like reliability.

 

[gjs238]

New spark-plugs were needed to the end of the war for each increase in
manifold pressure.
1.30ata - Bosch DW250ET 7
1.42ata - Bosch DW250ET 7/1.
1.80ata - Bosch DW250ET 7/1A and 10/1.
1.98ata - Beru F280 E43. (Driving the DB605DCM and ASCM to 2000hp)
The original spark plug on the DB605A was the Bosch DW250ET 7 and this
sometimes caused pre-ignition at 1.42ata MAP for the DB605A meaning
the Me 109G frequently had to be restricted to 1.3 ata
(atmospheres or Barr of pressure) as fuel quality was also a problem.

This Beru?
Beru (company) - Wikipedia

 

[swampyankee]

I think the Allies just had better, higher octane fuel. And access to better metals.

Put 130 octane into a Bf 109 modified for the much higher compression fuel and watch it fly. And give a Me 262 engines made of its intended alloys and metals and it will have Gloster Meteor like reliability.

I don't think anyone here would argue that there was something intrinsically inferior about German engines; I just think that there's no evidence that they were intrinsically superior, either. Fuel and material properties are something designers have to deal with.

 

[Zipper730]

Okay, I'm confused about something regarding the effects of rich and lean mixtures: I was under the impression that the rich mixture does better because the fuel injection into the fuel/air manifold cools it down and serves to make it harder to pre-detonate.

The Germans didn't do that, they shot it straight into the engine cylinders...

 

[Zipper730]

In addition the nazi tendency to flail around looking for a super weapon fortunately held them back as well. Lots of "amazing prototypes" but no organizational acumen to be able to develop them.

We were quite lucky as a result.

 

[tomo pauk]

I think the Allies just had better, higher octane fuel.
...
Put 130 octane into a Bf 109 modified for the much higher compression fuel and watch it fly.
...

Care to elaborate the two quoted sentences?

 

[fastmongrel]

I cant recall where I read it but British Scientists tested German fuel whenever they could get a sample probably from aircraft that did belly landings I dont think a smoking hole in the ground would provide anything to test. I cant remember the numbers but the top grades of German fuel dont seem to have differed greatly from the fuel used by the RAF. The Germans just got to a similar place by a different route.

 

[Denniss]

AFAIR the german C3 fuel was tested to have a rich octane rating between 130 and 150, depending on timeframe. I would assume the best quality is from an earlier 1944 timeframe with all production in full swing and no interruptions in the supply chain. With the massive attacks on fuel-related production facilities in mid 44 the fuel quality declined.

 

[tomo pauk]

Please, dont post the the stuff that goes against narative. We know too well that Germany didn't have hi-oct fuel. It is described just under the 'RR was hand-fitting the Merlins' gospel.

 

[Deleted member 68059]

AFAIR the german C3 fuel was tested to have a rich octane rating between 130 and 150, depending on timeframe. I would assume the best quality is from an earlier 1944 timeframe with all production in full swing and no interruptions in the supply chain. With the massive attacks on fuel-related production facilities in mid 44 the fuel quality declined.

It gets very VERY complicated with the fuel question, principally because of the use of direct injection. The definition of "high quality" becomes at least 2-fold more complex. First
you have the knock limit, THEN you have the knock limit across A/F range, THEN you have the distillation curve shape (which is fundamental to fuel/oil dilution AND of course if the stuff boils at high altitude, a very nasty set of limits... one to the left and one to the right!), then on top of that you have a severe problem with volatility and direct injection in-cylinder mixing and tubulence, which are magnified far more than if you use a carburettor (or port injection). These factors tend to form points on the circumference of a circle, with the engine in the middle. Not ALL these things are mutually exclusive but several of them are. Its much more involved than "was it 100 or 130 or 150 grade". On top of all of THAT, you have "can the engine actually USE the fuel to its knock limit or not ?".... AND you have chemical reaction considerations. For example highly aromatic fuels were found to attack platinum, and also to cause more valve head erosion. So you have a very multi-faceted problem to solve as a German WW2 fuels chemist.

I hate it when people say this, but to answer all that properly requires a book, which I why I wrote one. It will answer all these questions in great detail, and exactly what happened to German aero engines. (I`ll touch on perhaps 2 of the points above on Thursday in the webinar).

If you have a bit of basic fuels understanding, and a lot of time to spare, you can pretty much piece together most of the above from trawling the Fischer-Tropsch papers, but it will take a bit of time. (I recommend my book, as not only does it save you downloading loads of rubbish looking for the right reels, but I have everything referenced, so when you want to look it up in detail yourself, you just need to look at the references and you`ll be able to download the right TOM reel (Technical Oil Mission). A few details needed Daimler reports in papers from the Imperial War Museum. Sadly not digitised.

In the webinar on Thursday I`ll show you distillation curves for C2, C3 and modern AVGAS. that will tell you a lot.

 

[Koopernic]

I think the Allies just had better, higher octane fuel. And access to better metals.

Put 130 octane into a Bf 109 modified for the much higher compression fuel and watch it fly. And give a Me 262 engines made of its intended alloys and metals and it will have Gloster Meteor like reliability.

The DB605A, as the DB605AM achieved 1700hp on B4+MW50. It's my understanding that the DB605AM fitted to the Me 109G6AM used C3+MW50 and had the MW50 blown in by supercharger bleed of air but that the DB605AM used in the Me 109G14A used a mechanical pump and could work with B4+MW50. It was probably just a precaution to prevent the engine accidently running of B4 without MW50 and being destroyed.

Anecdotally Ive heard that the DB605B (same as a DB605A apart from gearing) used one Saab J21 achieved 1700hp on 100/130 fuel without MW50.

 

[fastmongrel]

Please, dont post the the stuff that goes against narative. We know too well that Germany didn't have hi-oct fuel. It is described just under the 'RR was hand-fitting the Merlins' gospel.

Strange that Narzi ubertech was so superior in every way but the fuel was so poor. With western fuel V2 rockets would have reached New York.

 

[Deleted member 68059]

Alexander von Philippovich was one of the most important fuels chemists in wartime Germany, and worked on Aviation fuel development as head of aviation fuels
research the DVL. This statement by him should not be taken out of context, as he is referring here JUST to the knock limit in the rich mixture region, and NOT
about the overall suitibility of fuels in all the other respects. However, yes, its clear that Germany absolutely DID have fuels which would (in principle)
allow an engine to run at basically similar boost ratings to any Allied engine. Sadly for them that got scuppered by other problems... of the sort I alluded to
in the previous post.

(This is in English as its a "German Oil Mission" transation done post-war: source imperial war museum)

 

[Koopernic]

Strange that Narzi ubertech was so superior in every way but the fuel was so poor. With western fuel V2 rockets would have reached New York.

A study of the fuel quality and quantity situation of fuels production reveals a great deal about the performance of Luftwaffe aircraft.

High Octane fuel was introduced into the Luftwaffe with the DB601N engines in the dying days of the battle of Britain. It was used on the Bf 109E and Bf 110 (As the DB601P) and latter Do 215. This fuel was nowhere up the spec of British 100/130 but seems to have been about 94/115. The DB601N/P was soon replaced by the DB601E and thereafter the DB605A which both ran on B4 87 octane. This "C" grade green dyed fuel seems to have been exclusively allocated to the BMW 801D. I've heard it claimed that BMW801 engines used on bombers often did not receive C3 and had their boost turned down.

The takeaway point should be that only a fraction of Luftwaffe aircraft were able to use this superior fuel. The DB601N in 1940/41 thence the BMW801D from 1941-45.
Larger scale use of the fuel on the DB605, DB603 and Jumo 213 from 1944 seems to have been abandoned due to the allied bombing campaign of the German oil industry.

From about early 1942 production of C3 was about 97/125 and more or less matched allied 100/130 in quality by the end of the year, British fuels intelligence noting the German engines were unable to exploit the potential of this fuel but that a powerful new engine could be expected.

From 1943 new emergency power system were introduced on the BMW 801D 'increased boost' (on A series fighters) and 'rich mixture injection' on F series fighter bombers. Latter the two systems were combined.

Again only a fraction of Luftwaffe aircraft were able to use this superior fuel.

In 1944 seemed to be available in much larger quantity and started turning up on the DB605AM/ASM engines of Me 109G6AM/G6ASM though seems to have returned to B4 use on the Me 109G14. Engines such as the DB603EM and Jumo 213E were to use C3 fuel.

About that time production fell due to the allied bombing campaign and the engine choices were modified to allow use of B4 fuel.

So broadly the Germans were lagging in both quality and quantity of high octane fuels. They caught up in quality by early 1942 and probably would have caught up in terms of quantity by 1944 but for the allied bombing campaign.

The reason seems to get down to 3 factors. The Germans were busy in investing in coal to liquids technology as a priority. iso-butylene that was needed for iso-octane synthesis was also needed for BUNA rubber production (no natural rubber was available to Germany) and the Germans were behind in commissioning acid alkylation plants. Acid alkylation plants were started in 1940 and at least one came on line in 1943. Without acid alkylation iso-octane was the main RON enhancer.

Acid alkylation was developed at BP in 1935 so it is no surprise and allied plants began operating in 1940.

Had the Germans had large amount of 100/130 its likely we would have seen a number of improvements
1 The Jumo 211 engine as used on Ju 88, Ju 87 and He 111 bombers would have had much more power.
2 Battle of Britain Bf 109E probably would have had 5% more power.
3 Me 109G1-G6 series would have been about 5% faster likewise the important Me 110 night fighter. Maybe 10% if the engine reached 1700hp.

 

[Koopernic]

View attachment 587327
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Alexander von Philippovich was one of the most important fuels chemists in wartime Germany, and worked on Aviation fuel development as head of aviation fuels
research the DVL. This statement by him should not be taken out of context, as he is referring here JUST to the knock limit in the rich mixture region, and NOT
about the overall suitibility of fuels in all the other respects. However, yes, its clear that Germany absolutely DID have fuels which would (in principle)
allow an engine to run at basically similar boost ratings to any Allied engine. Sadly for them that got scuppered by other problems... of the sort I alluded to
in the previous post.

(This is in English as its a "German Oil Mission" transation done post-war: source imperial war museum)

I suspect the implementation of a two stage supercharger is not practical until either a 100 octane fuel or water injection is incorporated. I'm thinking this may partially explain the failure of the Luftwaffe to develop and deploy two stage superchargers until 1945. The lack of two stage superchargers really seems to have hurt the Luftwaffe when dealing with the USAAF from 1944 onwards. It may have been implicated in Udets suicide.

 

[Deleted member 68059]

I suspect the implementation of a two stage supercharger is not practical until either a 100 octane fuel or water injection is incorporated. I'm thinking this may partially explain the failure of the Luftwaffe to develop and deploy two stage superchargers until 1945. The lack of two stage superchargers really seems to have hurt the Luftwaffe when dealing with the USAAF from 1944 onwards. It may have been implicated in Udets suicide.

The stages of compression used are to maintain whatever boost you have at sea-level, in fact raising boost tends to LOWER the (relative) effectiveness of any boosting system
because it makes it harder to maintain the power high up if you are highly boosted on the ground. The failure of the luftwaffe to impliment 2-stage SC has
absolutely nothing whatsoever to do with fuel octane or water injection.

Nobody knows exactly why Udet committed suicide, but I think its highly unlikely that two-stage superchargers had anything to do with it, as he died in
Nov 1941. At which point (from a technical perspective) the Luftwaffe was actually doing fairly well, the 109 F was doing well, and was competetive and
the 190 was entering service.

 

[cherry blossom]

Independent of fuel issues or supercharging problems, Germany suffered over 1943-4 because three engines which might have powered some of their their aircraft over that period were not available. The Bf 109 was always going to suffer as the Merlin moved ahead of the DB 605 at altitude but the Fw 190 family might have had a significantly better performance.

The problem with the DB 603 is simplest to describe and mostly comes down to lack of funding and the RLM's belief that the Jumo 213 was going to be a better choice. Thus even when the DB 603 was put into production in 1943, it was not available in large numbers and was not used by the Fw 190.

The dates of the early development of the Jumo 213 are obscure with best guesses including a first run in early 1939 or late 1938 and a first flight in July 1941 or earlier Junkers Jumo 213. However, the Jumo 213 remained unreliable until the firing order was changed from the original order of the Jumo 211 to the Rechlin Order in very late 1943 and finally and best to the Jumo 213E order as described in V-12 Firing Order Display "The three examples (213, 213 with Rechlin order, and 213E) show how changes in firing order made a reliable engine out of one that was breaking crankshafts. The problem was too many torque reversals per cycle. This was cured in the 213E by choosing a firing order that systematically loaded and then unloaded the crankshaft." It seems possible that had this problem been identified in 1942, an aircraft almost identical to the historical Fw 190D9 would have been the main German fighter from the Winter of 1943-4.

Finally, the Jumo 222 was hoped to become the main bomber engine until late 1941. I don't know why it didn't work but changes in the specification and thus in the cylinder bore obviously slowed development and possibly shortages of tin for the bearings also caused delays. The basic configuration was much later shown to work Dobrynin VD-4K - Wikipedia.

 

[Denniss]

AFAIR in 1942-43 they had a Jumo 222 ready for production but this was stopped by RLM requiring more power, sending the engineers back to the drawing boards.
Really strange the RLM did not see the need for fighter engines with better alt performance until it was very late (lots of B-17/-24 above Germany in 43). Also Mtt and DB tinkered too long with Me 209/309 and DB 603 variants instead of improving the DB 605 for the Bf 109.

 

[NevadaK]

AFAIR in 1942-43 they had a Jumo 222 ready for production but this was stopped by RLM requiring more power, sending the engineers back to the drawing boards.
Really strange the RLM did not see the need for fighter engines with better alt performance until it was very late (lots of B-17/-24 above Germany in 43). Also Mtt and DB tinkered too long with Me 209/309 and DB 603 variants instead of improving the DB 605 for the Bf 109.

Greetings Denniss,

My feeling is that Nazi procurement had a number of missteps from 1940 - 1944 that negatively affected the war effort. One seems to be chronic pattern of changing requirements, starts, and stops. This clearly affected several projects that never fully reached their potential. The other, which I think is more directly associated with this thread is that it appears the RLM tried to jump a level of development progression with the Bomber B Program and the associated power plants. IIRC, the power plants associated with this effort were all trying to double the HP associated with the best performing power plants at that time. Its hard to accelerate technology advancement and I believe that the failure to keep up with the Allies is partly linked to the failure of this effort.

Just my thoughts and there's a good chance I'm off the mark here.

Kk

 

[Shortround6]

Greetings Denniss,

My feeling is that Nazi procurement had a number of missteps from 1940 - 1944 that negatively affected the war effort. One seems to be chronic pattern of changing requirements, starts, and stops. This clearly affected several projects that never fully reached their potential. The other, which I think is more directly associated with this thread is that it appears the RLM tried to jump a level of development progression with the Bomber B Program and the associated power plants. IIRC, the power plants associated with this effort were all trying to double the HP associated with the best performing power plants at that time. Its hard to accelerate technology advancement and I believe that the failure to keep up with the Allies is partly linked to the failure of this effort.

Just my thoughts and there's a good chance I'm off the mark here.

Kk

You may be right or at least onto something. The Jumo 222 was not only supposed to be much more powerful, it was supposed to be compact, Germans had a bit of an obsession with twin bombers for low drag, Unfortunately the weight of the bombers went up faster than the power that could be had from just two engines.
Germans also (IMHO) tried to jump the manned gun turret and go straight to remote control defensive guns.
Some (or all?) of the bomber B projects also went for pressure cabins for the crew even though the requested operating altitudes were under 30,000ft.

A lot of different technical advancements in one bound.