Did the Allies Just Have Better Engines?

[bentwings]

Thinking about a number of posts in recent threads, it seems as if a critical advantage the Allies has during the crucial 1943-1944 time frame was aircraft power plants that were significantly better than those of the Axis. The inability of the Axis to develop comparable power plants was a major failing and a major factor in the outcome of the air war. Or, oversimplified:

Did the Allies just have better engines?

Your thoughts?

The Merlin was key to the P51 success and the Pratt&Qhitney R 2800 and their other radials were key to the p47,b24, and B25 and several others. Granted there were Axis motors that could have been very good but when you bomb the heck out of factories and have an idiot dictator. Good stuff doesn't matter. We had almost limitless funds and high production factories so we more or less ran over them.
I just read a sample of the book written on the development of the R 4360 P&w motor . They spent over 5 million 1940's dollars on just one motor development. I also think tactics were much better planned and executed. Just look at the kill scores. after the us gave more or less free hand find it see it shoot it to returning escort planes the axis ground movements were nearly paralyzed.

 

[Navalwarrior]

You do have to be careful when reading some of the old accounts/memo's.

If you see the phrase "from the Americas" for example it can very well mean from the British owned/controlled refinery/s in Trinidad that were processing oil from the region.
It may have nothing to do with oil or oil products from the United States of America.

the 100/130 fuel specification came into being after the BoB. BoB fuel was around 100/115-120 depending on batch. The performance number scale itself was developed after the BoB.

Resp:
I read that the British added 10% alcohol to their aviation fuel, and that it caused problems when used in the
P-38 Lightning in the ETO. If this was done, what if any affect did it have in various engines/carburetors? Thanks.

 

[Shortround6]

Resp:
I read that the British added 10% alcohol to their aviation fuel, and that it caused problems when used in the
P-38 Lightning in the ETO. If this was done, what if any affect did it have in various engines/carburetors? Thanks.

I would say that such an account is nonsense. The British and Americans had pretty strict standards for the number of BTUs per pound of fuel (alcohol has a lot less BTUs per pound than gasoline) and there were also standards for vapor pressure and evaporation. Not to mention problems with water in the fuel. If you get water in the fuel tank there are drains to let the water (heavier than gasoline) out during ground checks. Alcohol tends to mix with both gasoline and water making it harder to get the water out and then we are back to less BTus per gallon.
Using 10% alcohol would lower the BTUS by about 5% (I haven't done the math but alcohol, depending on type is about 1/2 the BTUs per pound.
Even if you rejet the carbs you just cut the range of the aircraft by 5%.
The P-38s problems were caused by a different additive/s to the fuel, improper cruise technique and more efficient intercooler than the pilots were used to/trained for.

 

[fastmongrel]

Resp:
I read that the British added 10% alcohol to their aviation fuel, and that it caused problems when used in the
P-38 Lightning in the ETO. If this was done, what if any affect did it have in various engines/carburetors? Thanks.

As Shortround6 has said above the fuel blend was strictly controlled. In Britain and then the continent after June 44 there wasn't a British only fuel depot or a US only fuel depot there was a universal network of depots and pipelines that fed to airbases.

I don't know what could happen if an engine set up for fuel containing 10% alcohol was accidentally filled up with alcohol free fuel or the other way round but it's not going to be good and could kill the crew.

 

[Koopernic]

The Merlin was key to the P51 success and the Pratt&Qhitney R 2800 and their other radials were key to the p47,b24, and B25 and several others. Granted there were Axis motors that could have been very good but when you bomb the heck out of factories and have an idiot dictator. Good stuff doesn't matter. We had almost limitless funds and high production factories so we more or less ran over them.
I just read a sample of the book written on the development of the R 4360 P&w motor . They spent over 5 million 1940's dollars on just one motor development. I also think tactics were much better planned and executed. Just look at the kill scores. after the us gave more or less free hand find it see it shoot it to returning escort planes the axis ground movements were nearly paralyzed.

The 110/150 fuel I contained xylidine and perhaps some aniline. Xylidine is the main component needed to make 110RON/150PN fuel, it is not an alcohol
150 Grade Fuel

It is sometimes mistaken for xylene which is an alcohol but not the same. Xylene is also an octane enhancer as well and used by hot roders. It is often added in those after market fuel tank injector cleaners etc along with acetone and toluene. Adding 30% xylene to a tank full of 87 MON will make it 92 MON.

The Germans added methanol (wood alcohol) to their A4 77 RON grade fuel which was used in training aircraft. Methanol is an excellent fuel and good octane enhancer. Methanol was easy to synthesise from coal derived syngas.

The issues with alcohols are usually
1 Cold starting (hence works well with fuel injection in harsh conditions)
2 material compatibility issues (corrosion, lubrication and dissolution issues)
3 tendency to absorb water
4 lower energy density.
It does however burn very cleanly and has a very high RON. All of the above can be solved by adjustments to materials.

Aircraft fuels also must not boil of at high altitude.

Of course both ethanol and methanol could have been added to WW2 aviation fuel as an octane enhancer but generally wasnt for some of the above reasons.

Ethanol and Methanol was used as an anti freeze for water injection systems. For instance in the Luftwaffe MW50 was 50% methanol, 0.5% grease and balance water. There was also MW30 which used less methanol for less cold weather and also EW30 which used ethanol etc. In warm weather the Germans sometimes did not use any alcohol at all especially if the were not flying to high altitude.

The First P-47C to receive water injection received them as field retrofit kits. They were instructed to mix in alcohol as an anti-freeze. For some reason the UK stationed USAAF chose propanol ie iso-propyl alcohol. This then blew up engines when the water injection was engaged and made P-47 combat pilots reluctant to do so. Supplies of ethanol were then used.

Interestingly the Germans used xylidine in their Tonka rocket fuel so they must have planned mass production.

 

[swampyankee]

Xylene is not an alcohol; see p-Xylene | C8H10 | ChemSpider. Its formula is C8H10. Its alternate name is 1,4-dimethylbenzene. Alcohols need OH substituents.

 

[Reluctant Poster]

The 110/150 fuel I contained xylidine and perhaps some aniline. Xylidine is the main component needed to make 110RON/150PN fuel, it is not an alcohol
150 Grade Fuel

It is sometimes mistaken for xylene which is an alcohol but not the same. Xylene is also an octane enhancer as well and used by hot roders. It is often added in those after market fuel tank injector cleaners etc along with acetone and toluene. Adding 30% xylene to a tank full of 87 MON will make it 92 MON.

The Germans added methanol (wood alcohol) to their A4 77 RON grade fuel which was used in training aircraft. Methanol is an excellent fuel and good octane enhancer. Methanol was easy to synthesise from coal derived syngas.

The issues with alcohols are usually
1 Cold starting (hence works well with fuel injection in harsh conditions)
2 material compatibility issues (corrosion, lubrication and dissolution issues)
3 tendency to absorb water
4 lower energy density.
It does however burn very cleanly and has a very high RON. All of the above can be solved by adjustments to materials.

Aircraft fuels also must not boil of at high altitude.

Of course both ethanol and methanol could have been added to WW2 aviation fuel as an octane enhancer but generally wasnt for some of the above reasons.

Ethanol and Methanol was used as an anti freeze for water injection systems. For instance in the Luftwaffe MW50 was 50% methanol, 0.5% grease and balance water. There was also MW30 which used less methanol for less cold weather and also EW30 which used ethanol etc. In warm weather the Germans sometimes did not use any alcohol at all especially if the were not flying to high altitude.

The First P-47C to receive water injection received them as field retrofit kits. They were instructed to mix in alcohol as an anti-freeze. For some reason they chose propanol ie iso-propyl alcohol. This then blew up engines when the water injection was engaged and made P-47 combat pilots reluctant to do so. Supplies of ethanol were then used.

Interestingly the Germans used xylidine in their Tonka rocket fuel so they must have planned mass production.

The British version of 100/150 did not use xylidine, using methyl aniline. The American version did use Xylidine but did not go overseas. In fact the USN was dead set against xylidine.

 

[Reluctant Poster]

Resp:
I read that the British added 10% alcohol to their aviation fuel, and that it caused problems when used in the
P-38 Lightning in the ETO. If this was done, what if any affect did it have in various engines/carburetors? Thanks.

The bad British fuel myth. As I have pointed out in previous posts, Lockheed was blowing up V -1710s at a prodigious rate during the winter of 1943-44 in sunny California trying to solve the problems being expirenced world wide. Perhaps Ronnie Coleman and Basil Rathbone were sneaking over to Burbank and sabotaging the fuel.

 

[mikemike]

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.

Daimler-Benz proposed the DB603 to the RLM in the autumn of 1936 and received permission to develop the engine. On March 11, 1937, the RLM had development stopped, paying D-B's accrued development costs. The reason was that "in the BMW801, we already have an engine in development that will meet all our requirements in this power class". D-B people were sure that with properly funded and supported development, the 603 would have been ready for series production before the start of the war. Low-key development obviously continued in the form of the marine and tank derivatives (DB 503/507); the Daimler-Benz land speed record car of 1939 was intended to be powered by an early DB603 prototype (likely one of the ten engines that the RLM had financed) that had produced a test-bench output of 2800 HP with 3500 HP likely to be achieved. The RLM was still not interested, indeed it was considered to offer the engine for export (imagine Japan buying the engine program!). All that changed with the war; D-B received the first order for 120 engines on February 3, 1940. Series production started in 1941, but output was initially low (and was needed for any number of prototypes). Focke-Wulf made a preliminary design for a DB603 installation in the 190 in February, 1940, estimating that speed would rise by 50 km/h and the engine installation would even weigh less than the BMW801. The RLM was still not interested - the BMW is all we need for the Fw190. When the engine was available in production numbers, it was obviously needed for more important applications like the ME 410 - see above reasoning. From April, 1942, Focke-Wulf built three prototypes with the DB603 - V13, V15, V16. The V15 reached 696 km/h at 6950 m with combat (max continuous) power. Daimler-Benz brought the V16 to 724 km/h at 7000 m with Notleistung (take-off power), and with an improved supercharger to 722 km/h at 9000 m. Not needed, says the RLM, since the 190 will be used in the east, where high-altitude performance is irrelevant - the Me109 G is all that is needed in the West. Stymied by bureaucracy - a common theme in the Third Reich where know-it-alls with good contacts made the decisions.

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.

The Jumo 222 did work eventually. The most persistent problem stemmed from the bearings - plain bearings made of an RLM-mandated bronze alloy containing antimony instead of tin. Only when tin was used could that problem be solved. Incidentally it was found that lubricants containing sulfur worked better with highly-loaded bearings. The Jumo 222 suffered from its connection with bomber programs - bombers not needed, then again needed, meaning production was ordered, then cancelled, then ordered again. The engine was ready for production in December of 1942, but production and development capacities were repurposed for the DB603 and Jumo 213. The engine would have been just right for the He219 night fighter, which was seriously underpowered with the DB603 - see "Winkle" Browns opinion.

 

[Koopernic]

Xylene is not an alcohol; see p-Xylene | C8H10 | ChemSpider. Its formula is C8H10. Its alternate name is 1,4-dimethylbenzene. Alcohols need OH substituents.

Thanks, I was probably hastily looked up xylanol, which has the OH, but is categorised as a phenol or xylatol which is a sugar substitute and an alcohol.

 

[swampyankee]

Thanks, I was probably hastily looked up xylanol, which has the OH, but is categorised as a phenol or xylatol which is a sugar substitute and an alcohol.

Alas, a few years ago had to take organic chemistry. I was permanently changed.

 

[cherry blossom]

Alas, a few years ago had to take organic chemistry. I was permanently changed.

I hope that you could cope with the rearrangement. I am told that people who study organic chemistry have alkynes of trouble.

 

[Koopernic]

Daimler-Benz proposed the DB603 to the RLM in the autumn of 1936 and received permission to develop the engine. On March 11, 1937, the RLM had development stopped, paying D-B's accrued development costs. The reason was that "in the BMW801, we already have an engine in development that will meet all our requirements in this power class". D-B people were sure that with properly funded and supported development, the 603 would have been ready for series production before the start of the war. Low-key development obviously continued in the form of the marine and tank derivatives (DB 503/507); the Daimler-Benz land speed record car of 1939 was intended to be powered by an early DB603 prototype (likely one of the ten engines that the RLM had financed) that had produced a test-bench output of 2800 HP with 3500 HP likely to be achieved. The RLM was still not interested, indeed it was considered to offer the engine for export (imagine Japan buying the engine program!). All that changed with the war; D-B received the first order for 120 engines on February 3, 1940. Series production started in 1941, but output was initially low (and was needed for any number of prototypes). Focke-Wulf made a preliminary design for a DB603 installation in the 190 in February, 1940, estimating that speed would rise by 50 km/h and the engine installation would even weigh less than the BMW801. The RLM was still not interested - the BMW is all we need for the Fw190. When the engine was available in production numbers, it was obviously needed for more important applications like the ME 410 - see above reasoning. From April, 1942, Focke-Wulf built three prototypes with the DB603 - V13, V15, V16. The V15 reached 696 km/h at 6950 m with combat (max continuous) power. Daimler-Benz brought the V16 to 724 km/h at 7000 m with Notleistung (take-off power), and with an improved supercharger to 722 km/h at 9000 m. Not needed, says the RLM, since the 190 will be used in the east, where high-altitude performance is irrelevant - the Me109 G is all that is needed in the West. Stymied by bureaucracy - a common theme in the Third Reich where know-it-alls with good contacts made the decisions.



The Jumo 222 did work eventually. The most persistent problem stemmed from the bearings - plain bearings made of an RLM-mandated bronze alloy containing antimony instead of tin. Only when tin was used could that problem be solved. Incidentally it was found that lubricants containing sulfur worked better with highly-loaded bearings. The Jumo 222 suffered from its connection with bomber programs - bombers not needed, then again needed, meaning production was ordered, then cancelled, then ordered again. The engine was ready for production in December of 1942, but production and development capacities were repurposed for the DB603 and Jumo 213. The engine would have been just right for the He219 night fighter, which was seriously underpowered with the DB603 - see "Winkle" Browns opinion.

It seems that by December 1941 the Luftwaffe was becoming aware of the limitations of the BMW801. The In line V12 offered at least the same power but with much lower drag (the main reason the Fw 190D was faster) and could do the job on lower octane fuel. Gollub in this report concludes that that the BMW801 will remain unreliable for so long that Fw 190 production vs 109 should be less than 50:50 for quite a while due to maintenance difficulties until the engine matures, that the radials were only interim and that the V12 will be needed longer term.

BMW did get the 801 to 2000hp, did develop a 2 stage 4 speed version the 801R (not produced) and did develop a turbocharged version the 801TJ. The DB603/Jumo were pushing beyond this already.

I think they should have cause to regret putting the DB603 on the back burner. The 'management' of the Luftwaffe can be acknowledged for having a large number of high performance aircraft in service and in production in 1939 so many of their decisions made sense, else they could have been as poorly prepared as say France was. Delaying the DB603 seems to have been an unnecessary own goal.

This is a tidied up machine translation of the Austrian Luftwaffe "ace" Gordon Gollub's report comparing the Me 109F4 to the Fw 190A2 testing at the Luftwaffe's test and development centre at Rechlin. The Report is dated December 1941.
Kurfürst - Vergleichsfliegen Bf 109 E, Bf 110 C, Spitfire, Hurricane und Curtiss.


4: The following considerations are made regarding the already established production ratio of the FW 190 to the Bf 109: The engine is currently so unreliable that, in the opinion of Colonel Galland, the aircraft is only partially operational and an operation over the sea and England is currently out of the question.

According to engine experts, after many changes (already20 ) the BMW 801 C engine and D will only be so operationally secure in half a year at the earliest that it can withstand any load, i.e. is as ready for the front at the same standard as the DB 601E. (used on the Me 109F4)

For the longer term future, it it can not to be assumed that a reliable air-cooled engine will develop to the 2000 hp range. The development of this fine aircraft will mean that we will have to resort to liquid-cooled engines, despite the great advantages of air-cooled engines. It is intended to install the DB 603 as the next liquid-cooled engine after the BMW 801D in the FW 190.

It should also be said that the DB 603 is a completely new engine, which will also have its teething problems. It is not to be expected that this engine will appear at the front for at least a year, but at least then the 801 D will have just become fully ready for the frontline. The 801 C engine today only reaches 25 operating hours on average!! Technical difficulties will therefore last for a long time with the FW 190, while the only really front-ready fighter, the Bf 109 F4 or G (newly developed engine as well ! ) will remain so. The installation of the BMW 801 C and D can only to be regarded as an interim solution. Just as unsafe as the operation appears over the Channel, it remains over other seas or areas over Russia.

The composition of the pilots is no longer such that losses due to technical defects can be accepted. The use of the FW in the tropics will encounter major engine difficulties and the possibility of this will not be possible for a very long time.

As long as the BMW 801 can withstand only so few operating hours, i.e. with maintenance intervals reaches 50 hours, a lot of engines have to be pushed back.

This will create difficulties once several squadrons are converted to FW 190. The intended production ratio of about 50% FW 190 and 50% Bf 109 indicates the early conversion of other squadrons

Once this has been done, however, it is no longer possible to use these squadrons only over their own territory and either these technical defects on the engine must be stopped by then, or so many engines have to be pushed back that it is possible to change engines at an early stage, which is hardly to be expected. The development also clearly shows that the Bf 109 will always remain faster and have a higher climb rate than the FW 190.

However, the best climbing ability cannot be dispensed with If at the moment

it is sufficient in the peculiarity of the use on the English Chanel at the FW 190, or does not play such an exhaustive role, then its inferiority with BMW

801 C compared to the Bf 109 F 4 with 50% of the climbing time of the F 4 to 10000m must not be overlooked under any circumstances. With the BMW 801 D, the
inferiority is still estimated to be 25 to 30% of the climb performance of the Bf 109 F4.

From the considerations that have been made, the ratio of 50% for the FW 190 seems to be too high, even when taking into account the greater fire sensitivity of the Bf 109. gez. Gollob .

Distributor: GL Techn. Amt 2 x Genst.Leadership Staff Group T 1 x E'Stelle Rechlin 1 x For the correctness of the copy KdE 1 x Rechlin, the 6. 1. 1942. [gez.] Lieutenant and Adjutant

 

[xylstra]

Thinking about a number of posts in recent threads, it seems as if a critical advantage the Allies has during the crucial 1943-1944 time frame was aircraft power plants that were significantly better than those of the Axis. The inability of the Axis to develop comparable power plants was a major failing and a major factor in the outcome of the air war. Or, oversimplified:

Did the Allies just have better engines?

Your thoughts?

You all forget fuel Octane!! Also about the shape of the development curve and influence of available technical resources and strategic bombing disruption not to mention political in-fighting.

 

[David Wagner]

I agree with your assessment with some caveats. The BMW 801 (2550cubic inches) had the same swept volume as the Curtiss Wright R-2600 but the 801 was a better engine because it had a much lower frontal area and in addition the gear driven fan allowed a tightly fitted cowling. The Pratt & Whitney R-2800 however also had a much lower frontal area than the R-2600 plus 8% more swept volume and better cooling and aspiration. If things had of stayed with single stage two speed superchargers for both the BMW 801 and PW R-2800 (as used on the B-26) I dont think you could argue that the R-2800 was a much better engine, Maybe slightly better (probably a little lighter, a little more drag and ,little more power) but the difference is small. However the US fighters that entered combat service in 1943 (P-47, Corsair and Hellcat) all had either turbo-superchargers or two stage, intercooled superchargers with independent drives and this is where the USAAF gained a huge jump on the Luftwaffe in performance above 20,000ft.

So how long did it take for the Luftwaffe to catch up? Almost 2 years. History shows that their first two stage intercooled engines entered service only in 1945 (Jumo 213E on the Ta 152H and Jumo 213F on Fw 190D12 and DB601LA on Ta 152C). The Turbocharged BMW 801TJ entered service also in the dying days of 1944 with some Ju 88S and in 1945 with Ju 388L.

It is not quite as clear cut as that. The DB605 and DB603 were not as reliant on supercharging for basic power because of their high compression ratios and high swept volume design. In 1944 the Germans made significant hydrodynamic improvements to their single stage two speed supercharger designs that partially closed the gap in altitude performance with allied engines eg DB605ASM(enlarged and improved impellor) and BMW 801TS (improved impellor, improved head design). The final version of the BMW801F was likely to have been producing 2600hp. The improved fuels, increased boost and rich mixture injection meathe nt a 1943 BMW 801 had 1900hp not 1700hp.

The BMW801R with two stage supercharging, intercooling, 4 speeds (as two separate drives) was intended for the Ta 152C but bombing destroyed the tooling. There is not doubt had the German industry not been under such extreme pressure they might have rolled out these engines much earlier. The allied oil bombing campaign so reduced the production of C3 fuel that engines had to be delayed to accomodate the new fuel. The Ta 152C with DB603EM would have been in service in 1944 for instance.

The bigger problem on the Me 109G was the poor airframe tolerances and tooling problems. Had the Me 109G6 that met the P-51B/C in combat in 1944 had a retractable tail wheel, no gun bulges over the cowling and fully enclosed main wheel covers it would have been 5% faster (419mph instead of 399 mph). These were all features the Me 109G0 had (and lost due to weight growth) but and all features the P-51B/C had. When the new DB605ASM engine came into serivice in May 1944 the P-51B/C and Me 109G6 should both have been roughtly 440 mph aircraft. It was October 1944 before the Me 109K4 fixed these minor airframe issues.

But the K-4 was quite a remarkable aircraft. It could go from 0 to 31,000 ft in 7 minutes flat and manage 452 mph, with a powerful centralized armament of 3 cannon. That kind of advantage in top speed and climb would be all most fighter pilots could ask for. Only the Mk XIV Spitfire could compete with these numbers. Some German pilots said after the war that with the K-4 they could get out of any situation they wanted- just open the throttle and pull back on the stick.

 

[Shortround6]

powerful centralized armament of 3 cannon

????????
what three cannon?

 

[Milosh]

????????
what three cannon?

He must be referring to the replacement of the cowl MGs with cannons.

 

[Denniss]

probably the old myth with MG151s in the cowl. K-4 could not do 452mph either, only with experimental propeller.

 

[Koopernic]

????????
what three cannon?

Kurfürst - Geschwindigkeitseinfluß von 2 MK 108 unter den Flächen der Me 109 G.
These MK103 "Gondalla" weapons cost 6km/h speed at 525km/h at sea level at 1.3 ata boost. About 1.2%.

Below is the Me 109K6 which integrated the MK108 into the wings. This model didn't quite enter production. It is a mystery that Messerschmitt didn't design for the smaller MG131 machine gun (or other gun) to integrated in to the wing of the Me 109F or Me 109G from the very beginning as it could have avoided the cowling gun bulges that developed by retaining rifle calibre guns there and using the 13.2mm MG131 in the wing. The MG131 had the destructive fire power of 3 rifle calibre guns.

You need to zoom in on this image to appreciate it.

The Me 109K4 could do 452 mph with a thin bladed propeller optimised for speed though this reduced climb performance slightly. It could do 460mph with a scimitar (swept wing prop). More speed was possible with more engine power. The Me 109K14 was broadly an Me 109K4/K6 with a two stage supercharged DB605L engine estimated to be capable of 455mph at 1.75ATA boost. It had much better high altitude performance due to the two stage super charger. This model had an oval air intake to scoop in the thinner air at high altitude and a 4 bladed prop to grip the thinner air.

Many of the minor aerodynamic refinements on the Me 109K4 were on no brainer and should have been introduced with the Me 109G6.

There was life left yet in the Me 109. The Luftwaffe was trying to get rid of it. The Fw 190D12 EB with the Jumo 213EB engine was expected to be able to do 488mph. With the same engine the Ta 152H was expected to do 474mph, which is the same as the Jumo 213E1 version but without GM1 and at slightly lower altitude. They would have been a better match for the P51H.

 

[Shortround6]

Thank you but the original poster said

a powerful centralized armament of 3 cannon

which certainly sounds like he bought into the old MG 151s in the cowl information.

Guns outside the propeller arc usually aren't referred to centralized, however effective they might have been.

I personally don't really buy the one in the fuselage is worth two in the wing theory, especially against large bombers.