Switch the Axis and Allies planes during WW2 (1943 Western Front)
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Dogwalker
Senior Airman
The esigence of having all the engines capable to burn B4 was likely much more present in the late war for Germans.
Since there isn't a general shortage of fuel, and supply lines work efficiently, even if only 1/4 of the production is of C3, that isn't a problem. You can have a quote of engines that burn only C3. It's sufficient that existing C3 burning engines doesn't require more than 1/4 of the total production of fuel.
But when there is a general shortage of fuel, and your supply lines work on a daily emergency basis, even if your production is now of 2/3 C3, became vital for all the engines to be able of functioning with the other third too, since there will be days in which there are no other fuel avaliable.
Since there isn't a general shortage of fuel, and supply lines work efficiently, even if only 1/4 of the production is of C3, that isn't a problem. You can have a quote of engines that burn only C3. It's sufficient that existing C3 burning engines doesn't require more than 1/4 of the total production of fuel.
But when there is a general shortage of fuel, and your supply lines work on a daily emergency basis, even if your production is now of 2/3 C3, became vital for all the engines to be able of functioning with the other third too, since there will be days in which there are no other fuel avaliable.
wuzak
Captain
As I said before, one of the Meteor prototypes flew with Metrovicks F.2s in late 1943. The decision had been made, however, not to put the F.2 into production because of reliability and manufacturing (complexity) issues. Development continued through and after the war, and it evolved into the Armstrong Siddeley Sapphire.
Metropolitan-Vickers F.2 - Wikipedia, the free encyclopedia
Shortround6
Major General
It powered a prototype Meteor, first flight Nov 19 1943. It was also flown in the tail of a Lancaster starting the end of June 1943. After some redesigning and modifications it became the Beryl. There were several other engine types using it as a core, including ducted fans. Experience was used to design the larger Sapphire which was first run as a Metropolitan-Vickers engine but the jet engine work was turned over to Armstrong-Siddeley in 1948.
Shortround6
Major General
According the Kurfurst site, some engines could use both, It seems that top or similar HP ratings could be achieved with either B4 AND MW/50 or with C3 alone.
ANY engine can be run on a lower octane rated fuel. You just can't use as much boost and need to inspect the plugs a bit more often.
The US used to run a lot of the planes used for operational training (P-40s and the like) on 91 octane fuel. Since the planes were seldom operating at full gross weight (no under fuselage or wing loads and ammo only for gunnery training missions) the difference in performance wasn't that noticeable.
Ignition cam timing, dynamic static compression ratios, boost pressures all determine what octane is required.
Anyways, some fuel production/consumption figures:
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But with restrictions. The Bf 109 G-14 MW-Anlage-Karte of October 1944 makes it clear that the DB 605 AS can be run on B4 fuel but that the MW 50 boost system could not be used without immediately (sofort) destroying the motor.
It seems the type was usually run on C3, at least in the opinion of one captured Luftwaffe pilot.
Now we know that C3 was not always used, but it was obviously preferred. Also there was supposed to be a five minute (not three) gap between uses of MW 50. Maybe they were pushing that a bit operationally.
Aircraft fuelled with C3 and with tanks full of MW 50 were still being reported in intelligence reports very late in the war.
Cheers
Steve
DB 605 ASB 1850ps
Fuel B 4, special emergency power with MW 50 additional injection
Loader: Daimler-Benz-stage centrifugal blower driven directly by the engine. Speed control depending on the flight height above a hydraulically shiftable clutch.
Apparently, B4 + MW 50 is no problem.
Fuel B 4, special emergency power with MW 50 additional injection
Loader: Daimler-Benz-stage centrifugal blower driven directly by the engine. Speed control depending on the flight height above a hydraulically shiftable clutch.
Apparently, B4 + MW 50 is no problem.
The problem was that if the MW 50 ran out the engine was immediately destroyed.
That's probably why the document states quite clearly that B4 fuel can be used if no C3 is available..... "darf notfalls".
And later in the same document more restrictions and dire consequences in the event of not reacting correctly.
I think it is safe to say that it was preferred practice to run a DB 605 AS on the fuel for which it was designed and that was C3.
Cheers
Steve
I notice that you were referring specifically to a DB 605 ASB.
That's probably why the document states quite clearly that B4 fuel can be used if no C3 is available..... "darf notfalls".
And later in the same document more restrictions and dire consequences in the event of not reacting correctly.
I think it is safe to say that it was preferred practice to run a DB 605 AS on the fuel for which it was designed and that was C3.
Cheers
Steve
I notice that you were referring specifically to a DB 605 ASB.
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I suppose B-4 + MW 50 was entirely ok, with practical standpoint C-3 must have been preferred (as manual say) since C-3 had high enough knocking resistance to go on without pinging even if the MW 50 system run out/failed/or the pilot foolishly turned it off while still firewalling the throttle at boosts levels that the B-4 could not handle...
Well, yes it is; axial flow engines required development beyond WW2 technology. You also forget that the Russians had access to both technologies, but both the MiG-15 and '-17 were powered by developments of the Nene engine and proved excellent aircraft.
A promising engine with lots of potential; it was superior to the earlier Avons owing to the latter's tendency for compressor surge. Although blow off valves were fitted to the compressor section, a redesign of this was needed as it was found that the Avon's tapered compressor design was inferior to the Sapphire's and eventually RR fitted the Sapphire's to the Avon combustor and turbine section, which changed the fortunes of the RR engine; it was this later variant that was fitted to the Lightning.
Purely out of interest's sake, Cimmex, were you aware of Herbert Wagner? He was the first to build and bench test an axial flow gas turbine for aircraft; initially, he toyed with the idea of using the engine to drive propellers based on British patents, but dropped this and concentrated on turbojet development. Wagner's wiki page doesn't mention that he built the first working axial flow jet engine;
Herbert A. Wagner - Wikipedia, the free encyclopedia
Another pioneer that gets little publicity is Dr A. A. Griffith; the quintessential 'mad scientist', who came up with extraordinarily advanced concepts, such as ducted high bypass fans years before they were universally adopted for big jets. Note also his work for Metrovick.
Alan Arnold Griffith - Wikipedia, the free encyclopedia
We are talking about barely trained pilots under the stresses of combat. If you read the second excerpt you'll see that a pilot was supposed to be aware that the MW 50 had run out and , if he had any kind of boost selected, immediately abandon it to avoid damage (it actually says destruction) to his engine in the absence of MW 50.
The DB 605 ASB was one of only two Daimler Benz engines designed to be easily adjusted to use both fuel types (the other was the DB 605 DB) which makes an earlier post not really relevant to other DB 605 series engines.
Cheers
Steve
Yes, it's equivalent to "through the gate" on many allied types.
It's not really a question of how easy the system was to operate but whether and inexperienced and stressed young pilot would even notice that he needed to change his settings before the engine ate itself.
It's obviously not desirable to be running these engines on lower octane rated fuel. I don't believe that it would have been contemplated had Luftwaffe fuel supplies not been in such a parlous state by late 1944.
Cheers
Steve
It's not really a question of how easy the system was to operate but whether and inexperienced and stressed young pilot would even notice that he needed to change his settings before the engine ate itself.
It's obviously not desirable to be running these engines on lower octane rated fuel. I don't believe that it would have been contemplated had Luftwaffe fuel supplies not been in such a parlous state by late 1944.
Cheers
Steve
Hardly "vague" as you like to make out because the C3 fuel situation is clearly such that DB 601A series engines were replacing N series engines because supplying C3 was problematic
Yet production switched very quickly to B4 fueled aircraft once the E/N and F-1/2 production finished - as it was s/e fighters and some Bf 110s were the only aircraft using C3 -albeit for how long? -which leaves the rest of the Luftwaffe, the majority of aircraft and engines, using B4.
Civettone
Tech Sergeant
I already said this before, but Daimler Benz managed to upgrade their engines (with new spark plugs for instance) so MW 50 could be used with B4. This happened at the end of 1944 with the 605D series and at the beginning of 1945 with the 605AS series. Until then, B4 with MW 50 would damage the engine.
But I would like to come back to my previous question as to why no production DB 603 or Jumo 213 was used with C3. I can understand why they would limit C3 production, but fact is that all of them only used B4. C3, especially with MW 50 would make the Fw 190D or He 219 superior to anything the Allies had. I feel there must have been a technical objection, but have no clue what that could have been.
Kris
Source for "supplying C3 was problematic"...? There is no single word of "problematic supply" of C-3 in any of your sources. It is what you dream. There is mention of limited supplies of 601N supplies though.
Your show that decided was that DB 601A was to fitted to 110 two times, instead of 601N:
a) in late 1940, when available DB 601N engine was freed up for 109E production and
b) start of 1941, when it was decided to put 850 601N engines in active service (ie. double the amount). I suppose they needed all the engines for 109F, that production just starting.
But, your thesis is, that Luftwaffe, seeing "problematic supply of C-3", decided that the correct way to solve "problematic supply" was to equip ALL of its single engined fighters AND some 6 Wings (=all..?) of Zestörer with an engine that runs only on C-3....?
I cannot escape seeing there is strong wish to make it something different than it was, to the point of nonsense.I do not see big deal or conspiracy theorie or hidden meaning about asking the lead engineer before switching all fighter production to 100 octane, what 100 octane supply situation is. After all, once you fitted fighters with DB 601N, the only thing you can pour into them is 100 octane C-3. Apparantly whichs supply couldn't have been that bad if they went ahead with the plan.
After all, as I understand, C-3 was just post-processed B-4, so for the Germans it was pretty much sheissegal wheter to have 1000 tons of B-4 or 1000 tons C-3. They could have either through wonders of advanced chemistry. The latter option was probably more expensive because of extra work, but not really a supply problem.
Yes after producing some 2000+ aircraft that were C-3 fueled (ie. 110s, 109E, F1, F2), the C-3 fuel situation went so bad that they went on producing 20 000 Fw 190A running on C-3.
Of course 109 aircraft F-4 and above went back to B-4, but since C-3 fueled 109 aircraft engine were producing ca. 1200 HP, and they were replaced by B-4 fueled 109 aircraft that had 1400 to 1500 HP, nobody was complaining, at least on the LW side of the stick about that.
Of course this was foundamental pre-war engine development advantage - higher grade fuel was not real need until engines reached ca. 1600 HP (and corresponding boost level of ~ 1.5 ata), because of developing engines of 30-litre class before war. None of those Jumo or DB engines of 1941, 42, 43 needed more than B-4 until 1944, when boost and powers increased so that knocking could become a factor, at which point they all seem to just go back to C-3 again.
So now claim is that because majority of engines were using B-4, there must have been "problematic supply of C-3"... ?
We can of course completely rule out option that, since the majority of German engines did not need anything more than B-4 to produce 1200-1600 HP, those crafty Germans simply produced - well, what they needed: B-4, to their actual requirements?
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