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luftluuver
08-21-2008, 08:06 AM
It has been stated here that the 190A's engine had an overheating problem. Now I have never come across this in any of my reading except for the early 190A with the BMW801C engine.

Has anyone, besides the originator of the statement, come across anything about overheating with the BMW801D engine?

JtD
08-21-2008, 08:26 AM
Afaik, the problem had little to do with the engine, but with the lack of airflow around the rear cylinder bank which was solved with the introduction of cooling slots behind the cowling - which coincided on the A-3 with the introduction of the 801D-2 engine.

That cooling was efficient is obvious from the fact that the increased power output of later models did not require a change in the cooling capacity of the aircraft.

The BMW801 is said to have had lubricant problems which slowed the progress of development, oil foaming iIrc. This would also indicate heat issues, but the problem was found in the lubricant and solved by changing it or some additions to it. Not sure where I heard that.

Xiolablu3
08-21-2008, 08:33 AM
I have read that the prototype overheated a lot, the aerodynamic cowel caused over heating, eventually it was removed.

http://www.ipmsstockholm.org/images/fw190v1_01.gif

Didnt the prototype use some form of evaporative cooling at one stage?

Bremspropeller
08-21-2008, 10:54 AM
Cooling-slots were first introduced with the A-2.

Kettenhunde
08-21-2008, 07:13 PM
The BMW801D2 had a problem with overcooling not overheating. The CG limits where expanded in the FW190A5. The extra room created in the engine compartment induced a power robbing cooling imbalance.

This was corrected with an attenuating ring.

All the best,

Crumpp

ElAurens
08-21-2008, 08:52 PM
I know this has been discussed before, but the overheat model in this sim is just flat wrong. Especially for the radial engined aircraft (with one or two exceptions).

M_Gunz
08-22-2008, 03:35 AM
The problem with early higher ATA causing the exhaust stacks to burn off -- that was not
engine overheat, correct? Yeah I know it got fixed and 1.42ATA was used! Short times there
was this and that with so many planes, I am not trying to characterize the series!

Bremspropeller
08-22-2008, 06:09 AM
I know this has been discussed before, but the overheat model in this sim is just flat wrong. Especially for the radial engined aircraft (with one or two exceptions).


Couldn't agree more.

Usually, we should have to deal with shock-frosting at high alts, not overheating.

joeap
08-22-2008, 08:09 AM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I know this has been discussed before, but the overheat model in this sim is just flat wrong. Especially for the radial engined aircraft (with one or two exceptions).


Couldn't agree more.

Usually, we should have to deal with shock-frosting at high alts, not overheating. </div></BLOCKQUOTE>

+2 from what I have heard from real pilots.

Kettenhunde
08-22-2008, 09:50 AM
The problem with early higher ATA causing the exhaust stacks to burn off -- that was not engine overheat, correct?

Hi M_Gunz,

That was knock limited performance and by June 1942 the Geschwaders were running normal engines alongside de-rated ones.

When the Alkane ratio of C-3 was adjusted earlier that month, the knock limits of the fuel were increased.

All the best,

Crumpp

mortoma
08-22-2008, 08:34 PM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I know this has been discussed before, but the overheat model in this sim is just flat wrong. Especially for the radial engined aircraft (with one or two exceptions).


Couldn't agree more.

Usually, we should have to deal with shock-frosting at high alts, not overheating. </div></BLOCKQUOTE>Actually overheating is at times more of a problem at high altitudes than it is at lower altitudes. Believe it or not. The air up high is indeed cold but it's so thin and the oxygen molecules so far apart that engine cooling up high is not as efficient as you think. If you don't believe me, go to your local airport and ask some pilots of higher performance reciprocating engine aircraft that commonly are flown up high. A good example would be the Piper Malibu and similar aircraft. I used to be a pilot so I know. Although I personally never flew higher performance or turbo-charged planes, I knew a lot of people who did. Closest I got was flying a guys Beech Bonanza a few times. I never went up high with it though. I wanted to avoid the supplemental oxygen.

Bremspropeller
08-23-2008, 05:51 AM
High-performance turbo-charged a/c of today are usually not radial-engined.
Their cooling-system operates differently.

I understand that some Mooneys have spoilers to enable powered-descends rather than pulling the engine to idle and watching it frost-up.

So there is a difference between a Bonnie or a Malibu and a P-47 or a Fw 190.

Kettenhunde
08-23-2008, 05:59 AM
Hi Brems,

You have hit upon a topic that gets argued back and forth on such places as the red board or the purple board.

Shock cooling stems from ******ing the throttle and entering a descent.

You are correct in that the spoilers on the Mooney allow it to make a full power descent avoiding any issue with shock cooling.

http://www.ramaircraft.com/Maintenance-Tips/Shock-Cooling.htm

http://www.avweb.com/news/maint/182883-1.html

All the best,

Crumpp

M_Gunz
08-23-2008, 07:16 AM
I would have thought that nitrogen in the air accounted for more cooling than the oxygen,
but I'm not a pilot.

Bremspropeller
08-23-2008, 07:31 AM
Doesn't matter if it's oxygen or nitrogen.

Cooling itself is done with any media that is cooler than the medium you want to cool.

Temperature-difference is a difference of speed and extent of molecular movement.
The higher the temperature, the faster and higher the molecule's swinging amplitude.

At 0 K (-273.16?C), there is no movement at all.

M_Gunz
08-23-2008, 08:41 AM
OTOH oxygen molecules are a couple protons and neutrons heavier than nitrogen....

Nahh, it just kind of stuck out the word oxygen instead of air is all. The intent was clear.