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Old 11-03-2018, 09:40 PM   #21
zhukov032186
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http://109lair.hobbyvista.com/articl...stigler_p2.htm

This is one of the interviews, now here he says the boost would fry the engine after a few minutes. He comments further you could use all of it just not more than a few minutes at a time. I'm intrigued now... this isn't the only interview I read but it's the only one I'm readily finding now (I once researched the Brown / Stigler story). I'm almost 100% certain he made comments in line with my earlier references in a different interview. I can only shrug and say I don't know atm, if I find amything else conclusive I'll pass it on.

You ninja'd me =)
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Old 11-04-2018, 01:18 AM   #22
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With all due respect, I highly doubt that Stiegler is correct and or has experienced a failure due to prolonged use of ADI. Id like to hear one scientifically sound reason why prolonged MW50 use at rated boosts would damage the engine beyond normal. This is completely irrational to me.

If you could run the the DB605 on C3 fuel without limit at 1,8 ata please explain to me why it shouldnt on B4 + ADI. There is simply no way that if the same engine that could tolerate 1,98 ata and even 2,3 ata at the Daimler Benz teststand, cooling would be insufficient at 1,8 ata + ADI which actually makes the engine run cooler. You have to change ignition timings, but thats it.

From an engineering pov the only engine part that is stressed beyond normal is the supercharger, because water droplets will cause damage at these really high rpms. The only other downside I can think of is corrosion through water, thats why there is always a fraction of oil added.
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Old 11-04-2018, 06:05 PM   #23
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Well, like I said, I'm 99% sure he said something different in another interview I'm not finding now. The 109lair one is poorly formatted, too =/ It's possible the other ones are lost now, I'll keep searching. Might have been a different pilot too, I just came across it while researching Stigler
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Old 11-09-2018, 06:32 PM   #24
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http://www.calum-douglas.com/

Link to an upcoming research project / book that I think will provide more insight into the engineering and capability of ww2 German recip engines than anything that's out there now. A must have item IMO if you are fanatical about this subject... I know there's a few of you out there lol.

It should provide a lot more insight into the actual performance and durability of late DB605 motors, as there seems to be a big information gap between known charts of projected performance, and anecdotal pilot reports. i.e. - no actual flight test data available to the public.

In current news, it looks like 1.8 and 1.98 ATA 109s will be represented soon in the Bodenplatte addon to IL2 Great Battles series, that will be interesting.

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Old 11-09-2018, 06:44 PM   #25
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Quote:
Originally Posted by rel4y View Post
With all due respect, I highly doubt that Stiegler is correct and or has experienced a failure due to prolonged use of ADI. Id like to hear one scientifically sound reason why prolonged MW50 use at rated boosts would damage the engine beyond normal. This is completely irrational to me.
G14 high altitude variants running DB603 compressors had reduced engine life due to excessive cylinder bore wear, like down to 15 hrs or so before replacement - AFAIR. Those were 1.7-8 ATA boost, so its not unreasonable to assume that a DB605D would suffer similar wear as a result of "excessive use of MW50". There was a severe shortage of hard metals at that time, so it can't necessarily be assumed that newer 605s were 'hardened' for higher boost durability. It may have happened, but I doubt it. Engine use limits in operating manuals seem to have been established as a projection / expectation before the actual motors were fully developed.

Of course you have inexperienced pilots abusing the motors, or the motors weren't properly broken in, various POL quality problems affecting output and durability etc. I'm SURE that loss of cylinder compression as a result of cylinder bore deterioration was a real problem, and was mentioned in several sources, which I am too lazy to rediscover, lol.

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Old 11-09-2018, 07:36 PM   #26
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i know his FB page, it is great
https://www.facebook.com/TheSecretHorsepowerRace/
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Old 11-09-2018, 09:12 PM   #27
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Quote:
Originally Posted by Barfly View Post
G14 high altitude variants running DB603 compressors had reduced engine life due to excessive cylinder bore wear, like down to 15 hrs or so before replacement - AFAIR. Those were 1.7-8 ATA boost, so its not unreasonable to assume that a DB605D would suffer similar wear as a result of "excessive use of MW50". There was a severe shortage of hard metals at that time, so it can't necessarily be assumed that newer 605s were 'hardened' for higher boost durability. It may have happened, but I doubt it. Engine use limits in operating manuals seem to have been established as a projection / expectation before the actual motors were fully developed.

Of course you have inexperienced pilots abusing the motors, or the motors weren't properly broken in, various POL quality problems affecting output and durability etc. I'm SURE that loss of cylinder compression as a result of cylinder bore deterioration was a real problem, and was mentioned in several sources, which I am too lazy to rediscover, lol.
You know, that's a good point, about deteriorating metal quality in later years, as that would def have created a gap between 'on paper' and 'reality'.
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Old 11-09-2018, 11:03 PM   #28
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Quote:
Originally Posted by Barfly View Post
G14 high altitude variants running DB603 compressors had reduced engine life due to excessive cylinder bore wear, like down to 15 hrs or so before replacement - AFAIR. Those were 1.7-8 ATA boost, so its not unreasonable to assume that a DB605D would suffer similar wear as a result of "excessive use of MW50". There was a severe shortage of hard metals at that time, so it can't necessarily be assumed that newer 605s were 'hardened' for higher boost durability. It may have happened, but I doubt it. Engine use limits in operating manuals seem to have been established as a projection / expectation before the actual motors were fully developed.
Really interested in that book, thanks for the hint! Not only G-14 AS, but also all ASB, ASC, DB and DC variants were running the larger DB603 supercharger. In the September 44 K-4 manual it states normal 50h intervals for engine inspections and with C-3 fuel the engine is not time limited in any way at 1.8 ata.

I hear lots of anecdotal claims that MW50 would burn out the engines really fast, but I dont see a scientific reason behind it. The ADI actually causes lower combustion temperatures as I have said several times now. As the water is evaporated during combustion it turns into steam and soaks up tremendous amounts of heat, while the steam causes a good but safe (because late) increase in cylinder pressure. Then it basically steam cleans the cylinder and exits through the exhaust while also having decreased the exhaust temps.

In this doc from 20.01.45 (http://www.kurfurst.org/Engine/Boost...DC_20-1-45.pdf), Dr. Scherenberg from Daimler Benz explains that "troubles with white flame with subsequent burned cylinder can be mostly attributed to inferior fuel quality". And I think this is really where the crux lies. Basically what happened was that detonation occured due to too low octane and contaminated fuel and completely wrecked the cylinders. But that is no effect that could be attributed to ADI. ADI actually is supposed to prevent exactly this damage from happening. I say it again, I very much doubt that engines were wrecked due to prlonged use of ADI.

Btw DB responded to this problem by retarding the ignition point and decrease knocking of the engine which causes a loss of 50 HP at Sondernotleistung. Also of note is, that this document talks about that on the eastern front mainly B-4 fuel was used so to this front it is important to give out the information about ignition retardation as soon as possible. Which implies that on the western front C-3 fuel was in frequent use. Considering the overall number of LW aircraft at that point it probably werent that many.
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Old 11-10-2018, 04:57 AM   #29
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Quote:
Originally Posted by rel4y View Post
Really interested in that book, thanks for the hint! Not only G-14 AS, but also all ASB, ASC, DB and DC variants were running the larger DB603 supercharger. In the September 44 K-4 manual it states normal 50h intervals for engine inspections and with C-3 fuel the engine is not time limited in any way at 1.8 ata.

I hear lots of anecdotal claims that MW50 would burn out the engines really fast, but I dont see a scientific reason behind it. The ADI actually causes lower combustion temperatures as I have said several times now. As the water is evaporated during combustion it turns into steam and soaks up tremendous amounts of heat, while the steam causes a good but safe (because late) increase in cylinder pressure. Then it basically steam cleans the cylinder and exits through the exhaust while also having decreased the exhaust temps.

In this doc from 20.01.45 (http://www.kurfurst.org/Engine/Boost...DC_20-1-45.pdf), Dr. Scherenberg from Daimler Benz explains that "troubles with white flame with subsequent burned cylinder can be mostly attributed to inferior fuel quality". And I think this is really where the crux lies. Basically what happened was that detonation occured due to too low octane and contaminated fuel and completely wrecked the cylinders. But that is no effect that could be attributed to ADI. ADI actually is supposed to prevent exactly this damage from happening. I say it again, I very much doubt that engines were wrecked due to prlonged use of ADI.

Btw DB responded to this problem by retarding the ignition point and decrease knocking of the engine which causes a loss of 50 HP at Sondernotleistung. Also of note is, that this document talks about that on the eastern front mainly B-4 fuel was used so to this front it is important to give out the information about ignition retardation as soon as possible. Which implies that on the western front C-3 fuel was in frequent use. Considering the overall number of LW aircraft at that point it probably werent that many.
Well there is one area where the engine was sure to be subject to increased strain, and that is simply mechanical effects. More RPM, More power = More mechanical load on internal components. Bearings are a particular concern- overheat them (via friction) and the engine will soon cease to function.
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Old 11-10-2018, 11:44 AM   #30
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As rel4y already said the engine was rated to make these exact same revs and the exact same amount of power with C3 fuel without time limitations...
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