Two things need to be looked, too, when talking about Jumo 213 - 1st, the early examples from 1944, used on 1st Fw-190D-9, were displaying 100 HP less power, than what was promised. Please check out the Fw-190D entry at Williams' site. Second, without captured AM-35 and AM-38, the Jumo-213 will not incorporate the intake guide vanes this early in ww2. That costs up to maybe 120-130 hp at altitudes lower than full throttle height. Those two factors combined reduce the take off power by at least 200 HP, so the '1942 Jumo 213' is not any better than BMW-801A.
Avoiding the Bomber B project
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DonL
Banned
To my sources the four gondula was the first and original plan and wood model (He 177B). From this base the He 177 was optimized to dive capacity and coupled engine as A version.
to the rest.
I partly agree with you, but their are certain issues. If I read my sources correct the most learning part from the german aero industry was between 1937-1940. THey developed the direct fuel injections and made the most progress of pressurized water cooling.
From my sources both companies learned a lot through the record flies and experimenting before the war with pressurized water cooling.
I refer here to experimenting and not war ready mass production.
The layout and water pressurized cooling of the DB 601 E existed since 1939/1940, but it was a way to get it in a serious war production.
My projection is, that the DB 604X, Jumo 222 and DB 606 had other engine engineering problems and solutions. The first goal was to create a base of a functioning engine.
I think this would be far easier with the natural developments of the Jumo 213 and DB 603, because they were natural developments right out a functioning base. The rest is tuning of RPM, cooling, superchargers and so on.
The DB 605 is from my claim a exception issue, but it worked much more and better then a DB 604X and Jumo 222. Also it was a kind of harum scarum introduction without proper testing.
From my logic and technical understanding the DB 601, DB 605, DB 603, Jumo 211 and Jumo 213 are very closed from the engineering process of the engine base and much more from the tuning and performance process compare the DB 604X and Jumo 222, so to my understanding there would be synergy effects if all the "natural" engines would be developed from 1938.
As I said before, I think we have seen a Jumo 213 and DB 603 in mass production at 1942, if both engines would be on a priority development from 1938 and without the DB 606, DB 604X and Jumo 222.
From the performance I can only estimate, perhaps 5% - 10 % less then the original, but that is very difficult to estimate, because the basics of performance tuning were learned before the war with this more "normal" engines and also at such a scenario all engineering development would be focused on the same issue, without the whole problem solutions of the other engines (DB 606, 610, Jumo222 and DB 604X)
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Shortround6
Major General
There is a lot of behind the scenes stuff that often does not come out in many books. I don't know what the actual status of some of the German progress was but some of the American progress may or may not be helpful.
The P W R-1830 started at around 2400rpm and went to 2550/2600rpm and then to 2700 rpm ( radials are harder in increase rpm on because of 7/9 cylinders on one crankpin). At some point ( I forget which) they changed the material (alloy) of the plain bearings they were using and this allowed the higher power/longer life and was judged to be such a success that P&W used on not only their own engines but shared the knowledge without compensation with air aircraft engine makers.
Airplane engines are not like car engines, it is not so much a matter of "tuning" for a higher rpm as making sure the bottom end holds together at the higher rpm/power. There used to be a semi joke about racing old Triumph sports cars ( the big 4 cylinder models) that said if you could turn 6000 rpm you were NOT making competitive horsepower. If you were making competitive horsepower the bottom end would fail at 6000 rpm.
Airplane engines ( at least the supercharged ones) walked a much finer line between weight (strength) and power. The Allison for instance used three different crankshafts that all weighed the same. The early ones were plain steel, followed by the same crankshaft except shot peened. The shot peened crankshaft would stand over 20% more stress for 100,000 cycles and would stand up to 95% of the stress for millions of cycles that would cause the plain crank to fail at 100,000 cycles. The SHot peened crank was followed by a nitrided and shot peened crank that showed an even bigger improvement. The nitrided crankshaft (introduced in early 1942) would run forever ( well over 10 million cycles) at a load 29% higher than the plain steel one would tolerate for 100,000 cycles. Later on Allison introduced the heavier counter weighted crank for even more improvement. Trying to use late 1942 or 1943 WEP power levels on a 1940 engine with a plain steel crankshaft just because you now had better fuel means the engine isn't going to last very long even if it doesn't suffer from detonation.
Maybe the Germans were already shotpeening and nitriding, I don't know. But if they were they might have been using the better strength to keep weight down rather than leaving "room" for later increases in rpm/power.
Better aluminium casting techniques allowed Allison E/F crankcases to require 10% less machining, be lighter and yet stronger than the "C" series crankcases.
Most of the time descriptions of engines focus on rpm, compression ratio, blower pressures and so on. Things that can easily be measured. Changes in materials, foundry techniques, alloys and heat treatment that allowed the engines to stand up to the higher power get much less attention. Like wright changing from the aluminium crankcases to steel ones to get 100 more rpm on some of their engines ( they also operated at higher boost/cylinder pressures) in some cases the crankcases were worth about 100 hp on the R-2600 engine. They didn't make the extra power but they allowed the extra power to be made with the same or longer engine life.
Just changing rpm by few hundred could cause a host of vibration problems because most of these engines used the lightest crankshaft they could, bare minimum of counter weights for the designed rpm.
Another photo of a Jumo supercharger impeller can be found here : 1943 | 2104 | Flight Archive
Somebody has to kick Junkers in the tail to stop them from using that impeller well before 1942/43.
You are correct that the Germans might have been better served by developing the existing engines rather than branching out to some of the odd balls.
But something to remember is that the odd balls were built to get around certain well known problems Like piston speed and cylinder size limits and not just because the designers thought they were clever.
Another thing to remember is that many of the aircraft engines were operating, on a power to weight ratio, on a comparable scale to some Grand Prix racing engines of the time. Except the aircraft engines were running on gasoline instead of exotic racing fuels and the aircraft engines had much greater durability. In other words the aircraft engines were every bit as 'cutting' edge as many Grand Prix engines and there was nowhere to go for help.
The P W R-1830 started at around 2400rpm and went to 2550/2600rpm and then to 2700 rpm ( radials are harder in increase rpm on because of 7/9 cylinders on one crankpin). At some point ( I forget which) they changed the material (alloy) of the plain bearings they were using and this allowed the higher power/longer life and was judged to be such a success that P&W used on not only their own engines but shared the knowledge without compensation with air aircraft engine makers.
Airplane engines are not like car engines, it is not so much a matter of "tuning" for a higher rpm as making sure the bottom end holds together at the higher rpm/power. There used to be a semi joke about racing old Triumph sports cars ( the big 4 cylinder models) that said if you could turn 6000 rpm you were NOT making competitive horsepower. If you were making competitive horsepower the bottom end would fail at 6000 rpm.
Airplane engines ( at least the supercharged ones) walked a much finer line between weight (strength) and power. The Allison for instance used three different crankshafts that all weighed the same. The early ones were plain steel, followed by the same crankshaft except shot peened. The shot peened crankshaft would stand over 20% more stress for 100,000 cycles and would stand up to 95% of the stress for millions of cycles that would cause the plain crank to fail at 100,000 cycles. The SHot peened crank was followed by a nitrided and shot peened crank that showed an even bigger improvement. The nitrided crankshaft (introduced in early 1942) would run forever ( well over 10 million cycles) at a load 29% higher than the plain steel one would tolerate for 100,000 cycles. Later on Allison introduced the heavier counter weighted crank for even more improvement. Trying to use late 1942 or 1943 WEP power levels on a 1940 engine with a plain steel crankshaft just because you now had better fuel means the engine isn't going to last very long even if it doesn't suffer from detonation.
Maybe the Germans were already shotpeening and nitriding, I don't know. But if they were they might have been using the better strength to keep weight down rather than leaving "room" for later increases in rpm/power.
Better aluminium casting techniques allowed Allison E/F crankcases to require 10% less machining, be lighter and yet stronger than the "C" series crankcases.
Most of the time descriptions of engines focus on rpm, compression ratio, blower pressures and so on. Things that can easily be measured. Changes in materials, foundry techniques, alloys and heat treatment that allowed the engines to stand up to the higher power get much less attention. Like wright changing from the aluminium crankcases to steel ones to get 100 more rpm on some of their engines ( they also operated at higher boost/cylinder pressures) in some cases the crankcases were worth about 100 hp on the R-2600 engine. They didn't make the extra power but they allowed the extra power to be made with the same or longer engine life.
Just changing rpm by few hundred could cause a host of vibration problems because most of these engines used the lightest crankshaft they could, bare minimum of counter weights for the designed rpm.
Another photo of a Jumo supercharger impeller can be found here : 1943 | 2104 | Flight Archive
Somebody has to kick Junkers in the tail to stop them from using that impeller well before 1942/43.
You are correct that the Germans might have been better served by developing the existing engines rather than branching out to some of the odd balls.
But something to remember is that the odd balls were built to get around certain well known problems Like piston speed and cylinder size limits and not just because the designers thought they were clever.
Another thing to remember is that many of the aircraft engines were operating, on a power to weight ratio, on a comparable scale to some Grand Prix racing engines of the time. Except the aircraft engines were running on gasoline instead of exotic racing fuels and the aircraft engines had much greater durability. In other words the aircraft engines were every bit as 'cutting' edge as many Grand Prix engines and there was nowhere to go for help.
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DonL
Banned
I have serious doubts, that you can generalize this with the claims from Williams site, according to Dietmar Hermann's book "An Illustrated History of the FW 190 D Series", I can't see any serious substance of this claim in general.
Also Mr. Williams site tend to show normal to underperformance graph's of german a'c's
Do you have any prooves for this theory or claim?
I've read this long time ago (here, just under the speed graph):
Lutz Naudet placed these performance trials in context:
Now lets come to the interpretation as to why both Wk.-Nr. 001 002 generally fall short of calculated values. The first problem with all flight trials of Wk.-Nr. 001 002 is that they were done with the initial batch of production engines, which have well documented problems with supercharger performance. Those first production engines produced 60-100PS less than the book values used for performance calculations. The second problem is the engine gap.
That is from Williams' site. I do admit that I don't know how much mr. Naudet 'weights' in ww2 circles, but I'm prepared to learn.
You might want to check this thread, and I'm, again, prepared to learn more about the stuff posted there.
Any thoughts of discussing these claims with Mr Williams, who, after all, has gone to all the hard work of finding, paying for and posting the information? He is also a member of this community, so perhaps you should PM him first with your concerns before dissing his site; whenever I've discussed things with him I've found him to be extremely helpful.
- Thread starter
- #47
wiking85
Staff Sergeant
I get your point about the early versions of the Jumo 213, but how much of that was due to the incorporation into the Fw190 airframe, as I recall the FW190A had similar issues with the BMW801 that the bomber version did not have. So for Ju88 and other bomber configurations would this have necessarily been an issue? Also at this time IIRC bombers weren't operating above 20,000 feet for the most part, so would the supercharger problem affected low altitude performance as much?
DonL
Banned
@ tomo
To Dietmar Hermann' there were deviations at the power output of the Jumo 213, mostly through production issues, so to me the claim that the issue is only on the Jumo 213 engine is to general. A tooling and production change in Germany late 1943/1944 is much more difficult then early 1942 through bombing, logistics.and material stortages.
Also your thread to the supercharges. Till now I haven't read any german source, that gave suspicions moments, that this developments are copied from the UDSSR.
Contrariwise there are many german developments, where you can read that is was copied from allied or other hardware, for example Rotterdam Gerät, snorchel, T34, 12cm mortar etc.
To me it is unusual, that there is no german source with a direct reference to this issue, because from my other examples there were german sources with direct references to the foreign developments.
Could it be a simultaneously development from both countries?
Just as the flying wing concept at Germany and USA?
To Dietmar Hermann' there were deviations at the power output of the Jumo 213, mostly through production issues, so to me the claim that the issue is only on the Jumo 213 engine is to general. A tooling and production change in Germany late 1943/1944 is much more difficult then early 1942 through bombing, logistics.and material stortages.
Also your thread to the supercharges. Till now I haven't read any german source, that gave suspicions moments, that this developments are copied from the UDSSR.
Contrariwise there are many german developments, where you can read that is was copied from allied or other hardware, for example Rotterdam Gerät, snorchel, T34, 12cm mortar etc.
To me it is unusual, that there is no german source with a direct reference to this issue, because from my other examples there were german sources with direct references to the foreign developments.
Could it be a simultaneously development from both countries?
Just as the flying wing concept at Germany and USA?
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Maybe the bomber BMWs (801A) and fighter BMWs (801C D) were not run at same settings? Ie. the Kennblatt for the Do-217E notes that 2700 rpm and 1.32 ata can be used strictly for take off, while during the flight the maximum was 2400 rpm and 1.27 ata; OTOH, looking at the tests on Fw-190A-2 (BMW 801C, basically a BMW 801A for Fw-190), the engine was run at 2700 pm and 1.32 ata even at 5-6 km of altitude. In other words: more RPM and manifold pressure = more power = more problems?
The inlet guide vanes were increasing mostly the low-altitude performance, so, in case they are not installed, the low-alt power would've suffer.
At the page I've quoted, there is no say that only Jumo 213 was affected. We might note that in time Germany have had sufficient resources (prior 1944), many of important engines were affected with problems, and were running on reduced settings. DB-601E DB-605A have had Notleistung blocked for many months, the issues with DB-603A were documented several times here (quotes from the book about Do-217), the problems with BMW-801 stretched from hid 1941 until late 1942.
Maybe they (Jumo) did copied the Polikovsky's device, maybe they did not. It is a fact that Soviets have had that on their AM-34s by the time ww2 started.
The T-34 was not copied by the Germans
The Polikovsky's device is a small tidbit in engine development, and as such can be easily overlooked, specially on the West - the West was never much impressed by Soviet aircraft gear, bar maybe Il-2.The contemporary with AM-34 with the 'device' is Jumo 211A or maybe 211B. Maybe the engineers in Jumo did not have enough faith in that (pre-war), and decided to give it a try once they looked at captured Soviet stuff? It also might be that people at Jumo knew about the Szydlowski-Planiol supercharger, that was using radial guide vanes, and decided that axial vanes might do the trick better?
davebender
1st Lieutenant
Late 1930s Germany was the world's largest aluminum producer and airframe production was still relatively low. I'm confident 1938 Germany had plenty of aluminum for drop tanks if the Luftwaffe funds mass production.
DonL
Banned
I don't deny this, but till now I see nothing that prooves, Junkers copied this device.
I haven't read this at any book or most importantly by von Gersdorf, which is the bibel of german engine development.
For example the germans very explcit documented their copy of the cavity magnetron, what is also only a smal (but very important) part of a radar.
By the way they copied some issues from the T34 to develop the Panther and the germans documentd these, you can read this all by Spielberger.
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DonL
Banned
This is totaly nonsens, nobody with a little brain would built drop tanks out of one of the most important raw material.
davebender
1st Lieutenant
Must be a lot of stupid people in the world since most aircraft drop tanks are made of aluminum alloy.
DonL
Banned
But definitely not for mass missions.
Imagine the germans flew BoB with aluminum alloy drop tanks for fighter missions. Roundabout 1000 missions for the fighters per day, so 1000 aluminum alloy drop tanks per day, which are lost?
Also no Mustang, P-38 or P-47 flew with aluminum alloy drop tanks to Germany.
Suspicious mmmmmm?
Imagine the germans flew BoB with aluminum alloy drop tanks for fighter missions. Roundabout 1000 missions for the fighters per day, so 1000 aluminum alloy drop tanks per day, which are lost?
Also no Mustang, P-38 or P-47 flew with aluminum alloy drop tanks to Germany.
Suspicious mmmmmm?
IIRC the 150 gal tanks, used on P-38 and P-47 were from metal (Al exclusively). The 108 gal tank was from pressed paper.
Will have to acquire the book, not just that is good, but it is much more reasonable priced than the book about Junkers aero engines.
Panther did share with T-34 some things, like the sloped armor. In other stuff, it was all German - internal layout, suspension, engine choice, main gun more for AT work, rather to be all-around like, for example, Tiger's gun, or the one from Pz-IVG, 3 crew turret. Daimler's proposal was much more like T-34.
Will have to acquire the book, not just that is good, but it is much more reasonable priced than the book about Junkers aero engines.
Panther did share with T-34 some things, like the sloped armor. In other stuff, it was all German - internal layout, suspension, engine choice, main gun more for AT work, rather to be all-around like, for example, Tiger's gun, or the one from Pz-IVG, 3 crew turret. Daimler's proposal was much more like T-34.
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davebender
1st Lieutenant
Better to lose aluminum drop tanks then He-111s and Ju-88s for lack of effective fighter escort.
davebender
1st Lieutenant
CSS Virginia effectively employed sloped armor during 1862 and it was widely employed on naval gun turrets. Sloped armor was employed on German APCs during 1939. So I think you are giving the Soviets too much credit.
German medium tank which follows 15 ton 1935 Panzer III design would probably have sloped armor (at least on front) whether T-34 is encountered or not. It's mostly a matter of producing a tank large enough to allow adequate internal space with sloped armor.
German medium tank which follows 15 ton 1935 Panzer III design would probably have sloped armor (at least on front) whether T-34 is encountered or not. It's mostly a matter of producing a tank large enough to allow adequate internal space with sloped armor.
???The drop tanks developed for the Bf 109s and 110s in 1939/1940 were all wood: one reason the 109s didn't use drop tanks during the Battle of Britain was because the drop tank that was to have been used suffered from fuel seepage due to inadequate sealing. AFAIK the vast majority of drop tanks used by Germany were wood or other non strategic materials.
The Russians were the first country to develop and employ heavy, angled armour on all surfaces of a tank, including the turret so, yes, they deserve lots of credit for not only developing the construction techniques - which are very different for those using straight armoured boxes, and different to those required for the lightly armoured APCs - but for putting such a tank into mass production well before any other country.
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davebender
1st Lieutenant
Stalin built (or modernized) 4 large tank factories during 1929 to 1931. Ten years before Germany and USA built similar tank factories. So it's hardly surprising the Soviets were first to mass produce medium tanks.
It's true Germany was the world's biggest aluminum producer in 1939, but only increased their production roughly 30% to their peak in 1942.
The USA at it's peak was producing about 4 times more aluminum per year than Germany at it's peak.
But even America often used paper and wood for drop tanks.
