do the engine gauges still work properly?

[Catseye]

Originally Posted by xnomad

The ranges are all off as well. For instance at higher altitudes, according to the Messerschmitt manual, the coolant would be overheating at the indicated temperature we get in the game.

In the game you don't see the temperatures drop at higher altitude, which they should because it's colder up there and as the boiling point of water drops with altitude your coolant would be turning to steam at the indicated levels shown.

I thought coolant was in a closed looped system under pressure and atmospheric pressure would not have any affect?

Interesting if it does.

[ATAG_Bliss]

Originally Posted by kilosierra

The first time might be right, but isn`t the coolant system pressurized and that because the boiling point independent from the altitude?

No expert here, just guessing.

I'm no airplane engine expert, but I do know plenty about automotive engines. The reason the coolant system is pressurized is because it raises the boiling point almost 50 degrees F (212 + 50 in F). And that should be completely separate from atmospheric pressure, as the cap, overflow system, and t-stat(s) all play an important role in maintaining that coolant equilibrium.

Originally Posted by speculum jockey

If it wasn't pressurized then it would leak all over the place. Anything that contains a liquid or gas that is not meant to escape will be pressurized. Balloons, cans of soda, your air mattress. All pressurized.

No. It's pressurized to raise the boiling point of the coolant. It has nothing to do with keeping it from leaking. Once cap pressure is overcame, it will siphon (leak) right on by the radiator until it can be sucked back in. You could take a huge radiator, without a cap, and leave the level of coolant lower and the system will never leak (no pressure), but it won't be as efficient.

Originally Posted by Catseye

I thought coolant was in a closed looped system under pressure and atmospheric pressure would not have any affect?

Interesting if it does.

I'd have to agree with you. I don't see how it could be effected, but I don't know.



@All - I don't know how much better cooling you'll get with high altitude conditions. Obviously it will help, but remember the coolant is there to keep the internal engine (where combustion occurs - a temperature that only slightly varies (lean/rich) in the combustion chamber) Outside air helps to cool the coolant obviously, through radiators, but that cold outside air also makes the engine need less fuel at altitude (less air density/less volume of oxygen) and colder air + less fuel = hotter combustion temps which = warmer base engine to cool.

Again, I have no idea how much the efficiency of cooling is higher altitude (super cold air) on a tiny radiator, but so much else is reliant upon the water pump and combustion chamber temp as well.

Would be neat if someone could find an article on it!

[David198502]

this thread really starts to get interesting!thx for all your information.

[Blackdog_kt]

Actually, i'm pretty sure the Stuka has different temp limits per altitude band due to an unpressurized or "not pressurized enough" system (limits are stated in the game's manual).

There are also some tick marks on the 110's water temp gauges if you zoom close enough, they specify the max allowable temp for a variety of altitudes.

[xnomad]

That's why I'm confused by the bf 109's cooling chart in the Messerschmitt manual for the Emil. These are the temperature limits for coolant at altitude:

http://109lair.hobbyvista.com/techre...als/bf109e.pdf

0 km -> 100 C
2 km -> 95 C
4 km -> 91 C
6 km -> 87 C
8 km -> 82 C
10 km -> 78 C

It's similar to water's boiling point at altitude but about 10 degrees off. So it almost appears to be subjected to atmospheric pressure changes. However, as mentioned before in this thread, to be contained in the system it would need to be sealed, and thus pressurised, otherwise it would leak (especially in a fighter that can be found at different attitudes e.g. upside down). So there must be another reason for these temperature limits?

The manual also states that the coolant is merely water with some rust inhibitors and that 30% glysantin/glycol is only added when temperatures are around freezing.

The schematics for the cooling system show bleed valves for over pressure. The circulation pump seems to be part of the engine or there is a convection process that circulates the coolant?

Is it something to do with that air doesn't transfer heat as efficiently at altitude because it is less dense? However in that case the temperatures limits shouldn't need to change you would just have to open the radiator more.

Or are they precautionary limits as it takes longer to cool at lower air densities? However, I'd imagine the colder air would make up for this? I don't know I work in IT this is all beyond me.

[robtek]

My idea about the lowered allowed temps at alt. is simple that the thinner air can't transport enough thermal energy.

So, as the outlet-temperature of the radiators is the important value here (it is known how much thermal energy will be produced)
the pilot must control the indicated inlet temperature to a point where the radiator is able to cool the coolant to the needed max. outlet-temp.

[II./JG1_Krupinski]

Just an observation with the 109 coolant system. When taking a hit I've noticed the coolant escaping and when finally all coolant being evacuated, the water temp gauge would show it completely off the right side(as high as it could be).

In my observations of real life coolant failures (in automobiles however) this is the exact opposition. The gauge should be showing the minimum temperature.