Overcooling Engine

[FTC_Zero]

During a flight in the virtual winter of russia and staring of the temp gauges, I was wondering what effect it has to the engine if you overcool it, besides of drag for opening the radiators. Her tid and bit of you should not overcool your engine and most spects of aroplanes have nominal ranges. I think technochat also reports you overcooling if not mistaken, but I deactivated it. Furthermore, it appears to have no negative effect on the engine in IL2. How does it work?

[Dragon1-1]

IRL, it can cause improper lubrication because oil gets thicker and more viscous at low temperatures. This may lead to excessive mechanical wear on the engine components, potentially causing engine failure at high power and RPM settings. It will also shorten the engine's operational life even if it doesn't seize. Another factor is that engine components expand at different rates when heating up, so operating the engine below the design temperature will cause the tolerances to be slightly off, also increasing wear and contributing to problems at high RPM. The former is the reason why you watch oil temperature, the latter either cylinder head or water temperature, depending on the engine. Both need to be within parameters in order to fly safely.

 

In Il-2, I think that taking it all the way to full power or WEP when cold can kill the engine, but it's not harmful in short run. It is, however, something to watch, particularly when diving in a radial engined fighters, as they get a lot of airflow over the cylinders when going fast, and if the throttle is idle, they can overcool, which may then cause the engine to disagree with the high power setting that inevitably gets set during the pullout. I don't know how much of a factor it really is in the sim, but I do know it can, theoretically, kill an engine.

[FTC_Zero]

5 minutes ago, Dragon1-1 said:

IRL, it can cause improper lubrication because oil gets thicker and more viscous at low temperatures. This may lead to excessive mechanical wear on the engine components, potentially causing engine failure at high power and RPM settings. It will also shorten the engine's operational life even if it doesn't seize. Another factor is that engine components expand at different rates when heating up, so operating the engine below the design temperature will cause the tolerances to be slightly off, also increasing wear and contributing to problems at high RPM. The former is the reason why you watch oil temperature, the latter either cylinder head or water temperature, depending on the engine. Both need to be within parameters in order to fly safely.

 

In Il-2, I think that taking it all the way to full power or WEP when cold can kill the engine, but it's not harmful in short run. It is, however, something to watch, particularly when diving in a radial engined fighters, as they get a lot of airflow over the cylinders when going fast, and if the throttle is idle, they can overcool, which may then cause the engine to disagree with the high power setting that inevitably gets set during the pullout. I don't know how much of a factor it really is in the sim, but I do know it can, theoretically, kill an engine.

Thanks for the general explanation. I suppose life endurance and reliabilty issues are not really a factor in IL2. However, those high setting sounds interesting. I try some experiments..

Edited February 9, 2023 by FTC_Zero

[LukeFF]

If you try to throttle up an engine too quickly from an entirely cold and dark start, it will fail.

[FTC_Zero]

I tried a P47 dive from high alt in winter, while maintaining the RPM in the nominal range. At first the RPM gets unstable and the engine randomly seizes to function. That's neat. But not sure if it is caused by overcooling or detonations.

Edited February 9, 2023 by FTC_Zero

[RyanR]

Did they change the P-47 cool running at altitude? I remember having a heck of a time keeping heat in the engine when BoN was first released. Seems to be running much warmer now. 

 

-Ryan

[Jaws2002]

I don't know if you can over cool the engine in the dive in the game but in real world this was a real possibility.

 

In the IAR-80 manual, for longer dives, they ask to close the cowl flaps and in planes with two oil radiators to close the radiators, in order not to overcool the engine.

 

 

  here's the page translated with google.

 

[Dragon1-1]

50 minutes ago, FTC_Zero said:

I tried a P47 dive from high alt in winter, while maintaining the RPM in the nominal range. At first the RPM gets unstable and the engine randomly seizes to function. That's neat. But not sure if it is caused by overcooling or detonations.

Look at the gauges, if the cylinder heads are cold, it's probably overcooling. Engine damage in Il-2 is rather simplistic, you get the same symptoms if your oil leaks out, for example, so it's hard to tell from how it fails.

[FTC_Zero]

3 hours ago, Dragon1-1 said:

Look at the gauges, if the cylinder heads are cold, it's probably overcooling. Engine damage in Il-2 is rather simplistic, you get the same symptoms if your oil leaks out, for example, so it's hard to tell from how it fails.

Cylinder heads get super cold. But interesting that you mentioned oil. I realised that I also lost oil in that te stwhen fully open the cowling. How, I don't know.

3 hours ago, Jaws2002 said:

I don't know if you can over cool the engine in the dive in the game but in real world this was a real possibility.

 

In the IAR-80 manual, for longer dives, they ask to close the cowl flaps and in planes with two oil radiators to close the radiators, in order not to overcool the engine.

 

 

  here's the page translated with google.

 

In many flight manuals it is advised to close radiators in a dive, where you throttle down your engine and have high air speed.

[Dragon1-1]

5 hours ago, FTC_Zero said:

Cylinder heads get super cold. But interesting that you mentioned oil. I realised that I also lost oil in that te stwhen fully open the cowling. How, I don't know.

Did oil pressure drop? Oil also contracts in the cold, I don't know how it would affect the oil pressure, but if it got too sticky to move around the engine, the gauge would probably show something weird.

[FTC_Zero]

1 hour ago, Dragon1-1 said:

Did oil pressure drop? Oil also contracts in the cold, I don't know how it would affect the oil pressure, but if it got too sticky to move around the engine, the gauge would probably show something weird.

I think there is no oil pressure gauge for the p47. However, for some reason, while the cylinder temp is falling very low, the oil temp is skyrocketing even with fully open oil shutters. That might the resons for the engine failure. Now I am super confused xD

[Dragon1-1]

There is, it should be there for every WWII aircraft since it's quite important IRL. In fact, at the time most cars had one (now on everything but racing cars you only get a light that usually turns on when it's already too late to save the engine). On the P-47 and most other US aircraft, the oil temperature is a gauge with three scales and three needles. On top there's a big temperature scale, and below there are fuel and oil pressure needles.

[FTC_Zero]

1 hour ago, Dragon1-1 said:

There is, it should be there for every WWII aircraft since it's quite important IRL. In fact, at the time most cars had one (now on everything but racing cars you only get a light that usually turns on when it's already too late to save the engine). On the P-47 and most other US aircraft, the oil temperature is a gauge with three scales and three needles. On top there's a big temperature scale, and below there are fuel and oil pressure needles.

Alright that I mistook the oil pressure gauge for the oil temp. Meaning the oil pressure skyrockets in the dive and now it makes sense why I look oil. But why is that happening?

[Dragon1-1]

Is there anything weird happening with oil temperature, then (same gauge, scale on top)? Again, if it's too cold, weird things might happen to the pressure gauge. Make sure you're reading the triple gauge correctly.

[Yogiflight]

8 hours ago, Dragon1-1 said:

Did oil pressure drop? Oil also contracts in the cold, I don't know how it would affect the oil pressure,

The oil pressure should be higher when the oil is cold, not lower. You can see this in cars with an oil pressure gauge.

 

7 hours ago, Dragon1-1 said:

There is, it should be there for every WWII aircraft since it's quite important IRL.

I don't know for the P-47, but in German aircrafts, the oil pressure is not really animated. The gauge always shows the same oil pressure, when the engine is running.

[FTC_Zero]

45 minutes ago, Yogiflight said:

The oil pressure should be higher when the oil is cold, not lower. You can see this in cars with an oil pressure gauge.

 

I don't know for the P-47, but in German aircrafts, the oil pressure is not really animated. The gauge always shows the same oil pressure, when the engine is running.

Why you guys just dont try it? When temp goes lower thatn 50deg then the oilpressur skyrocket and it doesnt take long to make the engine fail.

Edited February 10, 2023 by FTC_Zero

[FeuerFliegen]

I've had various engine damage happen before from an overcooled engine.  The majority of the time it has happened, is because I spawned in on the ground from a cold start (and didn't have the "Warmed Up Engine" setting selected).  I once had an oil system failure in a Po-2, simply from taxiing and not even throttling it up to over 80%, as it was very cold and I started to taxi just about 20 seconds after startup.  Other than that, I usually would only get engine damage if I pushed the engine past max continuous settings.

 

I have been meaning to make another post about engine temperatures on here; 

 

Based on my experience, I doubt it has much if any effect, but I've wondered if engine temperature has any effect on power output, assuming that you are NOT overheating or overcooled.  The sim will allow you to get to some very cold temperatures without an overcooled warning coming up, and I assume that in real life, these temperatures would equate to much lower engine performance.

Edited February 10, 2023 by SCG_FeuerFliegen

[FTC_Zero]

1 minute ago, SCG_FeuerFliegen said:

I've had various engine damage happen before from an overcooled engine.  The majority of the time it has happened, is because I spawned in on the ground from a cold start (and didn't have the "Warmed Up Engine" setting selected).  I once had an oil system failure in a Po-2, simply from taxiing and not even throttling it up to over 80%, as it was very cold and I started to taxi just about 20 seconds after startup.  Other than that, I usually would only get engine damage if I pushed the engine past max continuous settings.

 

I have been meaning to make another post about engine temperatures on here; 

 

Based on my experience, I doubt it has much if any effect, but I've wondered if engine temperature has any effect on power output, assuming that you are overheating or overcooled.  The sim will allow you to get to some very cold temperatures without an overcooled warning coming up, and I assume that in real life, these temperatures would equate to much lower engine performance.

It seems to differ from machine to machine. The P47 seems to be very sensitive to overcooling. When trying out the FW190A8, nothing happens.

[FeuerFliegen]

26 minutes ago, FTC_Zero said:

It seems to differ from machine to machine. The P47 seems to be very sensitive to overcooling. When trying out the FW190A8, nothing happens.

 

 

29 minutes ago, SCG_FeuerFliegen said:

I've wondered if engine temperature has any effect on power output, assuming that you are NOT overheating or overcooled.

 

 

I edited my post to make this correction^^  I meant to ask if there is any effect on engine performance within the very wide range of temperatures that you can achieve without getting an overcooling or overheating message.  Like the Fw190, you can be nearly anywhere from 40-85 deg C, without overheating or overcooling.  I wonder if either of these temperatures would perform differently.  Can't test it because of too many other factors.

[FTC_Zero]

23 minutes ago, SCG_FeuerFliegen said:

 

 

 

 

I edited my post to make this correction^^  I meant to ask if there is any effect on engine performance within the very wide range of temperatures that you can achieve without getting an overcooling or overheating message.  Like the Fw190, you can be nearly anywhere from 40-85 deg C, without overheating or overcooling.  I wonder if either of these temperatures would perform differently.  Can't test it because of too many other factors.

I see no difference other than engine failure or no failure at all. At least I do not see a speed loss which is not related to engine damage or radiator drag.

[Yogiflight]

4 hours ago, FTC_Zero said:

Why you guys just dont try it? When temp goes lower thatn 50deg then the oilpressur skyrocket and it doesnt take long to make the engine fail.

I just tried it with the FW 190 A5 and you are right in so far, the oil pressure rised a little with an oil temperature of about 25°C, when I throttled up to max power. But absolutely no issues. I could easily hold max power until my oil temperature was back above 60°C. And the rise of the oil pressure was hardly noticeable.

In the first Mazda MX5 (Miata) you could clearly see the difference in oil pressure between cold and warm engine.

[FTC_Zero]

9 hours ago, Yogiflight said:

I just tried it with the FW 190 A5 and you are right in so far, the oil pressure rised a little with an oil temperature of about 25°C, when I throttled up to max power. But absolutely no issues. I could easily hold max power until my oil temperature was back above 60°C. And the rise of the oil pressure was hardly noticeable.

In the first Mazda MX5 (Miata) you could clearly see the difference in oil pressure between cold and warm engine.

Yeah, same with the a8 before(fully open cowling flaps). Pressure jumped a tiny bit but with no issues at all.