Author Topic: German Language article on BMW801D boost systems  (Read 2662 times)

Offline MiloMorai

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German Language article on BMW801D boost systems
« Reply #30 on: December 15, 2004, 06:03:27 PM »
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Nice set of drawing Bentley does, the man is an artist, no doubt. Why should I do that when I have access to the real thing?


So how do you get the tank past the oxy cylinders 190 expert? The distance between the middle oxy cylinders was 425mm. The distance between the rear oxy cylinders was 390mm. The tank is 500mm in dia. (to the nearest 5mm)

Offline MiloMorai

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German Language article on BMW801D boost systems
« Reply #31 on: December 15, 2004, 06:52:58 PM »
quote: In early 1944 the USAAF started showing up over the Luftwaffe airfields. Being bounced on take off became an increasily common occurance for the Jagdwaffe. Most fighter pilots wanted their A/C as light as possible. Removing the outer MG151's and the 115liter Aux tank helped in that goal.


More confusion by Crumpp.

quote: It is actually very logical once you understand that C3 emergency power was available ONLY for use in jabo-einsatz's from the FW-190A5 until late 1944. It could ONLY be used at altitudes BELOW 1 KM. Having an extra 7.5 minutes of WEP would have been very useful especially when you consider the fact the Jabo's did most of their flying at low altitudes.

quote: I wonder if they used the "rated" motors in the Fighter units and when they reached replacement time, removed them, rebuilt them, and installed them in ground attack versions.

quote: AFAIK a "rated" power egg is one that is essentially fresh from the factory and on it's first operational hours after break in. Depending on the time period of the war, this could be as short as 30 hours of operation. Obviously rated power eggs developed more power and better performance.

A "de-rated" power egg has been rebuilt after it's first hourly life cycle.


First he says the jabos needed the extra power but then has 'derated' motors put in them and we all have been told that 'derated' motors run at less boost.:confused:

Offline Crumpp

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German Language article on BMW801D boost systems
« Reply #32 on: December 15, 2004, 07:59:43 PM »
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First he says the jabos needed the extra power but then has 'derated' motors put in them and we all have been told that 'derated' motors run at less boost.


All that is true Milo.  You don't seem to understand what derating is used for in regard to aircraft engines.

Please do a search on Google for "derated engines".  You will learn a lot.

Derating is a tool used to manage engines and extend life or operation of that motor.  The most common reason engines are derated is to use up inferior grade aviation fuel.

Talk to a mechanic.  Usually motors get better with rebuilds.  Occasionally they do not.  The stress put on Military fighter engines meant some motors developed micro-cracks and other flaws which kept them from realizing the benefits of a rebuild.

A motor that did not quite make specs after a rebuild could still be a good motor with lots of service life left in it.  Derating it allow a Military to continue it's use without having to scrap the motor or damage it while operating it.

Fighters need performance to tangle with enemy fighters.  That is their primary mission.

Jabo's primary mission is to destroy enemy ground targets.  Putting ordinance on a target is the order of the day, not raw performance.  Jabo's were supposed to have fighters escorting them to keep enemy fighters at bay.  Did not always work out that way but it was Luftwaffe doctrine to provide a fighter escort.

So it only makes sense that depot level maintenance would send derated motors to the Ground Attack Units.

 
 
Quote
AFAIK  a "rated" power egg is one that is essentially fresh from the factory and on it's first operational hours after break in. Depending on the time period of the war, this could be as short as 30 hours of operation. Obviously rated power eggs developed more power and better performance.


I now know any motor can be derated.  I encourage you to learn.

Crumpp

Offline Crumpp

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German Language article on BMW801D boost systems
« Reply #33 on: December 15, 2004, 10:26:32 PM »
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If so, what was the time limit for 1.42 ata in engines cleared for 10-15 mins 1.58/1.65 ata?


1.42ata is the 30 minute rating on the FW-190A8.

Crumpp

Offline MiloMorai

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German Language article on BMW801D boost systems
« Reply #34 on: December 16, 2004, 01:07:55 AM »
You get funnier and funnier all the time Crumpp.

Tell us how does a derated engine get the extra power you claimed the jabos needed?

When did the Fw change to using B4 fuel? Or, have you changed your definition of 'inferior'?

"All 190's did use C3. That was the fuel type they burned."

Would just love to be in an a/c that had a questionable engine, when I am flying at a height that was too low for 'taking to the silk'. As schwarze man says, "Can you imagine being allocated a de-rated 190?!!!!!!!!"

"Evidence is anecdotal."

This about the removal of the aux tank in a fighter. Sorry but according to Barbi anecdotal evidence is not acceptable. ;) ;)

Here is another of Crumpp's jems.

"For the beginning of May 1944, 881 FW-190's were in service in the Luftwaffe. 265 were Jagd-einsatz's and 387 were Jabo-einsatz's (serviceable). The rest where allocated to 5 StukaGeschwaders that were converting from the JU 87 to the FW-190F/G and IV/JG3 which was forming as a Sturm unit."

He then states,

"There are many more FW-190A8's around than ETC 501 racks. Why? Unless a pilot was flying a mission that required a 300 liter drop tank or a bomb the rack was removed as it was optional."

Yet there was more 190s that required the ETC501. (69-70% of production)



Still waiting for you to tell us how you get the aux tank through a narrower opening than the tank.

Offline Crumpp

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German Language article on BMW801D boost systems
« Reply #35 on: December 16, 2004, 04:49:14 AM »
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Tell us how does a derated engine get the extra power you claimed the jabos needed?



It does not, Milo.  Your Point is??  Your splitting hairs again.  
You do realize that extra power is a great thing to have for any Military aircraft?  Please provide a link to the conversation.  

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When did the Fw change to using B4 fuel? Or, have you changed your definition of 'inferior'?


Never have I claimed the FW-190A used B4 fuel.  Why are you lying?  

Please go and learn about fuel.  How it is made and the different things that affect the quality.  There is a lot more to it than just octane.

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"Evidence is anecdotal."


Milo.  I don't understand what your hard on is all about.  Do you have access to the aircraft?  How many people do you know who have removed the 115-liter tank from an FW-190?

I do have access to a real FW-190 and people who have removed the 115-liter tank.  Additionally I have asked Luftwaffe veterans who flew the FW-190 and clarified it's removal in combat.  Lastly for every picture of an FW-190A8 with the "cruising tank", you will find many more without it.

 
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"There are many more FW-190A8's around than ETC 501 racks. Why? Unless a pilot was flying a mission that required a 300 liter drop tank or a bomb the rack was removed as it was optional."


Please provide a link to this statement because I am pretty sure you have taken it completely out of context.  I guarantee the meaning of this is FW-190A8's not using the ETC 501 rack as opposed to FW-190A8's using it.  It only took 15 minutes to remove and replace.

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Still waiting for you to tell us how you get the aux tank through a narrower opening than the tank.


Why don't you visit the Museum? You can pick up the tank and put in the "auxiliary tank removal hatch" yourself a few times to see.

Crumpp
« Last Edit: December 16, 2004, 05:16:23 AM by Crumpp »

Offline MiloMorai

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German Language article on BMW801D boost systems
« Reply #36 on: December 16, 2004, 07:24:56 AM »
You really are lost Crumpp/Ketjg26.

Your the one claiming the jabos needed extra power.

You went on and on about the P-38 and 91 being an inferior fuel. So for the Fw, which used C3 fuel, it would have to use the inferior B4 fuel. German synthetic C3 fuel increased in potency as the war went on.


"Evidence is anecdotal."

Having a little fun, since Barbi outright dismisses such evidence. ;) At least I put names to my anecdotal evidence. Your the one with the stiff.



Ask how the tank got by the oxy spheres?

Offline Crumpp

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German Language article on BMW801D boost systems
« Reply #37 on: December 16, 2004, 08:29:59 AM »
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Your the one claiming the jabos needed extra power.



Just link to the thread.

I guarantee you misunderstood it.

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So for the Fw, which used C3 fuel, it would have to use the inferior B4 fuel.


No the FW-190A could not use B4, AFAIK.  It used C3 period.

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German synthetic C3 fuel increased in potency as the war went on.


Exactly.  What do you think they did with all the stocks of "inferior" C3.  

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Ask how the tank got by the oxy spheres?


The fuselage is wider at the bottom than it is at the top?  Anyway.  Not only does the FW-190 manual instruct you to remove the tank through the "auxiliary tank removal cover", it really does come out of the plane that way.

Crumpp

Offline MiloMorai

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German Language article on BMW801D boost systems
« Reply #38 on: December 16, 2004, 10:17:59 AM »
Quote
Originally posted by Crumpp

The fuselage is wider at the bottom than it is at the top?  Anyway.  Not only does the FW-190 manual instruct you to remove the tank through the "auxiliary tank removal cover", it really does come out of the plane that way.

Crumpp


No kidding :rolleyes:

Not disputing it came out bottom. Just explain how they got it past the oxy spheres which restricted its removal. Is that so hard to do? :eek:

Offline MiloMorai

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German Language article on BMW801D boost systems
« Reply #39 on: December 16, 2004, 12:09:46 PM »
see pg9. http://www.fischer-tropsch.org/Tom%20Reels/Linked/A5464/A5464-0638-0654%20Item%206A.pdf

"On the 25 Sept last year, attention was drawn in AI2(g) Report No 2111, to the high knock rating, under 'Rich Mixture' conditions, of German C-3 green av fuel then in use.

It was pointed out that while the standard German B-4 blue fuel, with an octane number of 89-90, had a 'Rich Mixture' rating of 81, the German C-3 green fuel - with 92-93 octane number - had a Rich Mixture' performance of 110.

During the past year there have been comparitively few C-3 fuel samples to examine, but the Committe on Energy, Oils and Fuels stressed in their report of the meeting held 30 June this year, that this C-3 green fuel gave a potential BMEF margin under 'Rich Mixture' conditions, which was not fully utilized by the existing German engines.

Since June 1943, however, test have revealed that the SG composition of the C-3 green fuel has been altered. The SG is lower at around .771 and, while the octane number is up slightly at 95>96, the 'Rich Mixture rating, as determined by 3C test (equivelent to the supercharged DFR engine) has increased considerably to around 125.

table left out

The reasons for this increase in 'Rich Mixture' rating are difficult to account for, since even with the original C-3 green fuel, the German aero engines were not capable of taking full advantage of the fuels potential. Nor are there indications of such improvement in the design of current German aero engines as to suggest that can take any greater advantage of either the original or the modified fuel.

The potentialities of this fuel should, however, to be borne in mind, as, in an improved design of engine, it would permit an appreciable increase in boost and BMEP
"

report dated Sept 16 1943

The Germans must have had lots of stock of the 'inferior' C-3 fuel to last at least 2 years. Now which C-3 fuel did the German bombers that needed it use. Since they only drop bombs must be the 'inferior' grade of C-3.

Offline Kurfürst

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German Language article on BMW801D boost systems
« Reply #40 on: December 16, 2004, 12:33:26 PM »
Quote
Originally posted by Crumpp

No the FW-190A could not use B4, AFAIK.  It used C3 period.


The BMW 801C of the early 190A versions (A-1, A-2) used B-4 fuel. ;)
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Offline Crumpp

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German Language article on BMW801D boost systems
« Reply #41 on: December 16, 2004, 01:46:32 PM »
Interesting! Do you have a reference?

It is not listed on the Flight Card in the FW-190A1 bis FW-190A2 Flugzeug-handbuch.



I don't seem to have documentation showing B4.  If you have some I would really appreciate a copy of it!

Crumpp

Offline Kurfürst

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German Language article on BMW801D boost systems
« Reply #42 on: December 16, 2004, 02:01:43 PM »
My reference is Jane`s WW2 Aircraft books engine section, but I have seen in other places as well that the 801C run at 87octane, this being the major differenence compared to the 801D (and s/c gear, compression). I remember some GLC chart on that though...

Technically speaking, the increased CR on the 801D is also a hint for changing for a better fuel, German engine development carried this pattern (ie. DB 601N, DB 605 D).

But keep in mind that an engine that runs on 87, can also run on 100 octane, but not vica versa. In particular, late DBs like the AM are also listed to use C-3, but the text, after reading it carefully actually does not rules out the use of B-4 as in other cases.
« Last Edit: December 16, 2004, 02:05:00 PM by Kurfürst »
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Offline Crumpp

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German Language article on BMW801D boost systems
« Reply #43 on: December 16, 2004, 04:33:38 PM »
And you are correct Izzy.  Just looked it up in the BMW 801 manual.  The BMW 801C did use B4.

The BMW 801D2 used C3 only.

Thanks!

Crumpp

Offline Crumpp

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German Language article on BMW801D boost systems
« Reply #44 on: December 17, 2004, 02:40:02 PM »
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Not disputing it came out bottom. Just explain how they got it past the oxy spheres which restricted its removal. Is that so hard to do?


How many times do I have to explain it, Milo.  They don't get in the way.

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The Germans must have had lots of stock of the 'inferior' C-3 fuel to last at least 2 years. Now which C-3 fuel did the German bombers that needed it use. Since they only drop bombs must be the 'inferior' grade of C-3.


What are the chances they experimented before arriving at the 1943 formula, Milo.  What are the chances this experimentation left them with usable but inferior fuel.

Crumpp