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BlitzPig_DDT
03-14-2004, 10:31 PM
Why do engines continue to burn when, after igniting, they are shut off, and throttles back to zero and flown fast enough to put out the flames?

It's frustrating beyond words. There is no fuel in them. They are not burning at the time, and yet, try to land and they re-light and blow you into a million pieces.

Doesn't matter if it's a turbine, or a recip. They both act the same way.

Can this please be changed?

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BlitzPig_DDT
03-14-2004, 10:31 PM
Why do engines continue to burn when, after igniting, they are shut off, and throttles back to zero and flown fast enough to put out the flames?

It's frustrating beyond words. There is no fuel in them. They are not burning at the time, and yet, try to land and they re-light and blow you into a million pieces.

Doesn't matter if it's a turbine, or a recip. They both act the same way.

Can this please be changed?

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Korolov
03-14-2004, 11:07 PM
How does shutting off a engine solve a fire problem? Or the throttles to idle for that matter? Diving is effective but only for so long. If theres a oil leak on the engine that caused the fire, I can see how it would catch on fire again real quickly.

Come to think of it, why are you even bothering with a plane that's on fire? The Pigs having some problems supplying planes to the pilots these days? http://ubbxforums.ubi.com/images/smiley/53.gif

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crazyivan1970
03-15-2004, 12:28 AM
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BlitzPig_DDT
03-15-2004, 10:46 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Korolov:
How does shutting off a engine solve a fire problem? Or the throttles to idle for that matter? Diving is effective but only for so long. If theres a oil leak on the engine that caused the fire, I can see how it would catch on fire again real quickly.<HR></BLOCKQUOTE>

Um, oh, I don't know, cutting off the fuel supply perhaps?

Man, you are really starting to reach for things to give me a hard time about. Says a lot about you. lol

So - you cut the fuel supply, then remove the flames via wind (from speed). Now - no fire, no fuel. Why should it relight when slowing down?

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Korolov
03-15-2004, 10:53 AM
Read carefully. I didn't say fuel, I said oil. You cut the fuel, you're less likely to explode, but AFAIK theres no easy way to cut the oil flow. If oil is leaking onto a hot engine, theres a very high chance it will ignite into a fire, and re-ignite even if you've dove the fire out. You've probably heard about the early Fw-190 models that had problems with engine fires, because of oil getting onto the hot engine.

So, you dive at 600+kmh, you'll put it out, but if you slow down, you get less air flow over the hot area, and IF there is oil leaking onto the engine, will re-ignite on the hot hunk of scorched metal.

The only engines I really have problems with explosives and fire on is the Me-262.

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BlitzPig_DDT
03-15-2004, 11:04 AM
Happens a lot on the P-38 and Bf-110 too. If anything, those might make more sense to be a burning problem as they are a lot more massive and not as easily cooled inside, particularly after shut down and the water pump stops.

A turbine on the other hand, especially the Jumo004, is much lighter overall. A lot less metal, and it's all much thinner. It won't carry heat as well or as long. It also has air going all the way through it, even when shut off. There's really no reason to assume it will stay that hot at high IAS.

Plus, oil burns slow. It doesn't explode.

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WWMaxGunz
03-15-2004, 01:03 PM
Oil on hot engine = smoke.
I get that on planes I hit all the time.
Lately on Russian and German bombers.
B-17's too if they don't light right up.
Fighters before then, smoke for long time traight.

I guess I assume the blackish smoke is oil smoke.

In the absence of flame or a spark there's no reaon for hot oil to inginte unless it is hotter than the flashpoint. And engine that hot... did not get that hot by running and will not stay that hot without steady heat applied.

I have to agree with the Pig on this one.


Neal

VaporBlast
03-15-2004, 01:46 PM
You'll know why when your car's engine ignite on the highway for no apparent reason. http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif

BlitzPig_DDT
03-16-2004, 10:45 AM
Bump++

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Cragger
03-16-2004, 12:04 PM
Coolant smoke is white

Oil smoke is grey

Fuel smoke is black

Hopefully we will see better engine damage modeling in BoB. EAW actually had better internal damage modeling but of course its graphics and flight engine weren't that great in comparison to IL2. Man I still remember a mission in EAW nursing a P-47 that was smoking and the MAP was all over the place all the way back to home plate. In Il2 you can't do this failure ALWAYS occurs it just takes time.

The problem I have right now is that given enough time a grey smoking engine will always progress to a billowing black smoking engine which will always progress to a fire given enough time (landing with a grey smoking engine in OMB and hit time accllerate and watch what happens).

Also alot of engines fail and give absolutely no idications of problems in either oil pressure (leaking oil = dropping pressure never shown in IL2)or head temperature and some like the 110 don't even show a decrease in manifold pressure until the engine dies (probably has something to do with how multiple engines are modeled.)

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BlitzPig_DDT
03-17-2004, 09:21 AM
Bumping again. Looking for an official response.

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p1ngu666
03-17-2004, 04:18 PM
its a pain.
if u shut the engine off, uve got VERY little heat genoration, its just windmilling if anything so the fire at x temp would happen once if u shutdown engine. some did reignight, but atm its ALL http://ubbxforums.ubi.com/infopop/emoticons/icon_frown.gif

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03-17-2004, 07:45 PM
Another complaint: you can control mixture independently for all engines.

If the #2 engine gets damaged, you should,
1) close throttle
2) mixture to off
3) feather prop
4) crossfeed righthand tanks to #1 engine
5) manually shut righthand oil and prestone radiators
6) etc, blah blah

Some things are obviously not modelled. For instance, every airplane has One Big Fuel Tank(tm), eliminating the need for fuel selectors and multiple gauges, and that's not such a big deal.

But, the mixture problem is real. Setting mixture to "off" (or 0% in sim terms) affects ALL engines, not just the one you've selected. As soon as you toggle back to your operating engine(s), the 0% mixture state clobbers whatever previous mixture state they were operating at.

AnalFissure
03-17-2004, 10:09 PM
try reducing mixture to cutoff on the damaged engine, then UNSELECT all engines, raise it back up to full rich, then select the working engine.

This should work, should it not?

AnalFissure
03-17-2004, 10:23 PM
Just tried it, and you can't manipulate mixture with no engine selected like you can with throttle or pitch if you've got them mapped to axes.

this means that yeah, as soon as you select the good engine it will turn off. but you can raise mixture and restart the good engine, while the bad one is still cut off (you can see it is if you look at the mixture levers -- on the he111 for instance).

The solution is to allow the "virtual" mixture level to be manipulated with no engine selected, or allow us to map mixture to a slider, or both.

HarryVoyager
03-18-2004, 12:36 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Korolov:
How does shutting off a engine solve a fire problem? Or the throttles to idle for that matter? Diving is effective but only for so long. If theres a oil leak on the engine that caused the fire, I can see how it would catch on fire again real quickly.<HR></BLOCKQUOTE>

R-3350 engine routinely threw oil through the exhaust system. Considering that on some of the early versions of the engine, the heat from the exhaust system was enough to melt unprotected magnesium cyliner heads (redesigns protected the cylinder heads better from the hottest components of the exhaust system), if the engine oil can survive that without ignighting, then you aren't going to have a major oil fire unless your engine is already a towering inferno.

It takes a considerable ammount to light off the engine oil.

On a side note, the problem with the BMW-801 engine was that the oil coolers were mounted ahead of the engine, effectively, completely unprotected from enemy fire. The oil coolers would get hit in head on passes, and the engine would lose all its lubricating oil. The black billowing oily smoke was the oil evaporating on the cylinder heads, not an oil fire.

Harry Voyager

Magister__Ludi
03-18-2004, 12:55 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by HarryVoyager:

On a side note, the problem with the BMW-801 engine was that the oil coolers were mounted ahead of the engine, effectively, completely unprotected from enemy fire. The oil coolers would get hit in head on passes, and the engine would lose all its lubricating oil. The black billowing oily smoke was the oil evaporating on the cylinder heads, not an oil fire.

Harry Voyager<HR></BLOCKQUOTE>


This is completely incorrect, it's just another glaring error originated in Carson's masterpiece.

Oil tank and oil cooler in a Fw-190 are protected under first two armored cowling rings, so yes they are under armor. If shot from close distance the armor could be penetrated, but the bullet will loose the kinetic energy. Similar damage to any other plane would cause even more severe damage, probably immediate loss of engine.

Charos
03-18-2004, 02:23 AM
Good Question;
Example ME262: Engine Fire - You select Engine then Shut it down put out the Fire with a bit of speed. 10 Minutes later on approach to base the Engine is STILL Smokeing and will ignite on aproach to base.
#1 Doesnt the ME262 Run on Fuel approaching dieseline?
#2 are not the Engine's fed by seperate Fuel Pumps?

From Pilot's Manual:
EMERGENCY SHUTDOWN OF JET UNIT DURING FLIGHT
a. Jerk Throttle Closed
b. Turn fuel pump off.
c. Turn fuel selector Valve off.

so if after 10 Minutes of the Engine being off - no fuel flowing, Engine core Temp at atmospheric Ambient. Why is the Engine Still smoking and still catching on fire?.

The Fuel Tanks are in the Fuselage and im shore most of any fuel in the Engine would of been blasted out of the Engine necelle by the forward velocity of the Aircraft as the Turbine and compressor would be Windmilling.

AcesHigh_AVG
03-18-2004, 09:37 AM
Maybe there is a leak in the wing or fuselage tanks and some gas is seeping into the engine compartment? Or maybe there are other liquids in the engine we haven't talked about that have leaked out and are burning? Also the only reason the fire goes out at high speed is because you have changed the fuel air mixture to a point where the fuel cannot burn. When you slow down the fuel air mixture become correct for burning and the fire reignites. It really doesn't have anything directly to do with cooling of the engine.

BlitzPig_DDT
03-18-2004, 11:27 AM
In order to burn, you need fuel and oxygen. It's hard to over oxygenate a fire. You'll just make it burn hotter. Ever do that experiment with pure O2 in HS physics? Take a popsicle stick, light it, then put the flame out so you just have a glowing ember, dip it in the oxygen and watch it burst into flames larger and brighter than before you put it out.

If you have the fuel, oxygen, and the required amount of heat, you have fire. If you put that fire out by large volumes of fast moving air, you have removed the source of combustion. You are further cooling everything off. If you get it cooled to below the flashpoint of the fuel, there is no further risk of fire.

So yes, it really does have everything directly to do with cooling the engine. Along those lines, you have convection from the rushing air over the block, radiator, and even cowling. You also have any fluids that happen to be leaking contributing to the cooling. Even av-gas, so long as it's not burning at the time. As the liquids hit, they evaporate and carry lots of heat off with them.

In short, once you douse the flames, and especially if you cut off the most flammable fuel supply (the av-gas or jet fuel), and run for a little bit, as mentioned several times above, there is no longer the heat required to support combustion.

As for other liquids, there's only 2 flammables, oil and fuel. Coolant is mostly water, and there wasn't really any other liquids in those engine compartments.

And in the case of turbines, theres far less mass, and the incoming air has far more direct access to all the hot parts. This combination of parts that hold less heat, and more direct cooling would mean that those engines would be even less of a re-peat fire-hazard that recips.

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BlitzPig_DDT
03-19-2004, 06:52 AM
Bump++

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p1ngu666
03-19-2004, 08:29 AM
on the engine side, with twin jets, u back say 2 down, now select all (u had engine 1 at 100%) and up number 2 goes

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JR_Greenhorn
03-19-2004, 09:59 AM
Clearly most of you have never had to extinguish an automobile fire before.

Oil smolders nicley deep inside its reservoir, even if that is cool.

It sure is a good thing that rubber hoses don't burn, and rubber grommets. Wire sheaths, too. I'm glad those things stop burning when you shut off fuel.
You know, that smoldering rubber goes right out when you cut fuel and cool the metal.

What did these planes have for filters? Ever seen an oil or fuel filter burn?

HarryVoyager
03-19-2004, 10:56 AM
But does the rubber generate free radicals fast enough to keep the reaction going when its in an airstream moving in excess of 100 mph? It does not sound as though it is a terribly fast reaction, indicating that is has a relatively high activation energy, so any free radicals swept away are going to have a significant impact on whether or not the reaction can continue.

By flushing the area with excessive amounts of air, you're going to strip the radicals off like there's no tomorrow, and unless the reacting compound has enough interal energy, in the form of heat, to keep forming more free radicals, in the absense of local exothermic free radical reactions, the reaction will fairly quickly stop.

I believe that's part of hte reason jet turbines are so difficult to air-restart, by the way. There is pleanty of fuel and air avaliable, but the air is moving through the system so quickly, that it pulling the free radicals right out of the engine before they have a chance to react.

In a static atmosphere, thats not a concern, as nearly all free radicals generated are able to react close to their point of origin, releasing their reaction energy back into the system, to continue perpetuating it.

Harry Voyager

BlitzPig_DDT
03-19-2004, 12:20 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by p1ngu666:
on the engine side, with twin jets, u back say 2 down, now select all (u had engine 1 at 100%) and up number 2 goes

http://www.pingu666.modded.me.uk/mysig3.jpg <HR></BLOCKQUOTE>

I find that if you are running with all engines selected, select the burning one singly (I have U for left, O for right since they straddle I), cut it, drop throttle to zero, then deselect it and quickly move the throttle back up to a point just below where you had it before, it's ok. You get the setting back up high enough that it can't fall too far and won't cut out on you, and also, since it's still falling, your movements won't cause it to combust.

Something I've thought of, but haven't tried yet is to deselect the good engine, then select the burning engine, then set throttle position and re-select the good engine. If you deselect it first, it might work. Need to mess around with that.

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