Cooling efficiency

[Reflected]

I'm not saying there is a bug here, but reading through the manual, I can't get our Jug behave like this.

The oil cooler:

The manual says I should open the oil cooler and let the oil temp drop below 50 before stopping the engine. Well, with the oil cooler wide open, it's just not possible on the ground, the temp needle just wouldn't drop, stays pretty high actually, even in a cold winter mission at -10C. See track.

coolingoil.trk

null

 

The other strange thing is the cowl flaps.

In game I close them fully once I'm airborne and never worry about it. I can't get the CHT climb higher than 230 with the cowl flaps closed even in a full throttle climb at 160 MPH on a hot summer day. See track. Never have I had to open the cowl flaps or increase climb speed even in hot weather:

coolingCHT.trk

null

What do you think? Am I missing something or the cooling model needs some adjustment?

[EnzoF98]

What manual is that from? (Edit: Nvm, found it) The first part seems odd to me, engine oil cooling down that much without any significant air going through the oil cooler because the aircraft is stationary with a running engine. Especially since you're supposed to heat it up to >40°C by running the engine at a lower RPM than the 1000-1200 range.

Another manual I found states: "b. When a cold weather start is anticipated, before stopping the engine, hold the oil dilution switch in the "ON" position for a period of 4 minutes at 800 rpm. The dilution of the engine oil while the oil temperature is above 70°C is not effective. If oil dilution is to be accomplished and oil temperature is too high, stop the engine until it has cooled to 40 to 50°C, restart it and proceed with the oil dilution." 

Note that this doesn't state a maximum oil temperature for engine shutoff and it specifically tells you to turn the engine off if you want to cool it down to below 50°C.

 

The second issue I can agree with, I've also never run into issues with high cylinder head temperatures. Don't think I've ever seen it over 230°C either.

Edited September 26, 2023 by EnzoF98

[Brigg]

230 is maximum for A/L 260 is max for A/R. Up high around 30k you have to start thinking seriously about CHT in game 

[Brigg]

On 9/23/2023 at 4:16 AM, Reflected said:

I'm not saying there is a bug here, but reading through the manual, I can't get our Jug behave like this.

The oil cooler:

The manual says I should open the oil cooler and let the oil temp drop below 50 before stopping the engine. Well, with the oil cooler wide open, it's just not possible on the ground, the temp needle just wouldn't drop, stays pretty high actually, even in a cold winter mission at -10C. See track.

coolingoil.trk 431.7 kB · 3 downloads

null

 

The other strange thing is the cowl flaps.

In game I close them fully once I'm airborne and never worry about it. I can't get the CHT climb higher than 230 with the cowl flaps closed even in a full throttle climb at 160 MPH on a hot summer day. See track. Never have I had to open the cowl flaps or increase climb speed even in hot weather:

coolingCHT.trk 1.12 MB · 3 downloads

null

What do you think? Am I missing something or the cooling model needs some adjustment?

If you are reading the manual edition I think you are then you reading a shut down procedure sequence that incorporates preparation for a cold weather start. This is the shut down procedure from a more generalised manual rather than block specific 

https://imgur.com/a/Ni0DxjZ

 

[Hobel]

vor 2 Stunden schrieb EnzoF98:

What manual is that from? (Edit: Nvm, found it) The first part seems odd to me, engine oil cooling down that much without any significant air going through the oil cooler because the aircraft is stationary with a running engine. Especially since you're supposed to heat it up to >40°C by running the engine at a lower RPM than the 1000-1200 range.

Another manual I found states: "b. When a cold weather start is anticipated, before stopping the engine, hold the oil dilution switch in the "ON" position for a period of 4 minutes at 800 rpm. The dilution of the engine oil while the oil temperature is above 70°C is not effective. If oil dilution is to be accomplished and oil temperature is too high, stop the engine until it has cooled to 40 to 50°C, restart it and proceed with the oil dilution." 

Note that this doesn't state a maximum oil temperature for engine shutoff and it specifically tells you to turn the engine off if you want to cool it down to below 50°C.

 

The second issue I can agree with, I've also never run into issues with high cylinder head temperatures. Don't think I've ever seen it over 230°C either.

 

i haven't looked at it that closely yet.

But BF109 and others had that too, but in the meantime that has been changed and the oil cools down more slowly, I would also say as you would expect.

track of it would be cool

[EnzoF98]

7 minutes ago, Hobel said:

track of it would be cool

A track of what specifically?

[Hobel]

vor 3 Stunden schrieb EnzoF98:

What manual is that from? (Edit: Nvm, found it) The first part seems odd to me, engine oil cooling down that much without any significant air going through the oil cooler because the aircraft is stationary with a running engine. Especially since you're supposed to heat it up to >40°C by running the engine at a lower RPM than the 1000-1200 range.

basically that

[EnzoF98]

17 minutes ago, Hobel said:

basically that

I haven't checked it yet, but I assume the first track in @Reflected's original post will show that behaviour.

[EnzoF98]

Was definitely able to get the engine oil down below 50°C, though it takes a little while even with -12°C ambient and the nose into a 6kt wind.

It was actually faster with the engine on than with it off, which is not what the 1943 manual suggests.

Tracks attached.

CoolingOilEngineOFF.trk CoolingOilEngineON.trk