Glycol leaks

[SCG_motoadve]

Glycol leaks on planes last quite a bit, actually I have never had an of the fighter seize the motor because of a leak.

Anyone has an idea hw much can you fly with a leak before the engine overheats?

Depends on plane and size of the hit, but still I feel they last a long time, just a feeling, not not sure if this is realistic or not, can only compared to loosing coolant on a dirt bike because a branch hit the radiator, 15 minutes later was overheating and had to stop.(Very small hole)

Plane systems are larger, but glycol tank on a 109 for example its pretty small, the radiator does not look too big either #20 in the picture.

 I assume the system has some pressurization?

#6 in the picture is the glycol tank.

 

Edited August 7, 2021 by SCG_motoadve

[357th_KW]

As you point out, it would depend on the leak, the aircraft flight regime, engine load, and ambient conditions.  It's worth noting that all cooling systems were pressurized to some degree, and on top of leaking more rapidly, the loss of pressure reduces the boiling point of the remaining coolant and thus the cooling capacity of the system.  I believe some 109s had a capability to cut off coolant flow to one side or the other, potentially saving some in the case of a leak, but of course you would be down to half your cooling capacity.  I've seen pilots describe flying for fairly long periods with a coolant leak or radiator damage - in one case a P-51 that overheated (though apparently without having suffered a puncture) and vented a bunch of coolant over Germany still managed to limp all the way back to England - this appears to have been a really exceptional case, as a malfunction or damage in the cooling system seems to have almost always resulted in an engine failure.  I've also read of a number of cases where a shot out radiator resulted in an engine fire within a minute or two.  BoX feels exceptionally forgiving of coolant leaks right now, to the point where liquid cooled engines seem tougher and more resistant to damage then air cooled engines do.

Edited August 7, 2021 by VBF-12_KW

[ZachariasX]

1 hour ago, SCG_motoadve said:

Anyone has an idea hw much can you fly with a leak before the engine overheats?

That would depend on the cooling system. Desireable cooling circuits like the one on the Merlins (one if its great design feature) was a relatively heavy pressurized system. This enables higher coolant temperatures and thus smaller radiators. You put a hole in that one, not only it will leak, but it will vent the system, depressurizing it, and getting your coolant to boil. Coolant must not boil anywhere in the system but in the expension tank. If boiling somewhere in the system does happen (usually in the hottest areas), the steam pockets create heat spots on the engine, typically around the valves and exhaust ports. Once you start burning youe engine in that place, you‘re also inviting predetonation. In short, in a pressurized system, you can kill your engine way before coolant has ran out, unless you cut back you power to get the coolant to ambient pressure, some 70C Centigrades or so, depending on your flight altitude of course.

 

The Germans had a not so cool radiator design that forced larger coolers on them, hence if you get holes in that one, you are nearer the boiling point of the coolant in ambient pressure. Still, if you don‘t react quckly (should you have that option), I would expect a DB605 burning its valves very fast, as that was anyway a systemic problem (due to material issues) of the engine even in best case. In these engines, you are really riding the very edge of what the cooling can give you.

 

The remaining pressure in the system in relation to the actual coolant temperature should define what (if at all) cooling your engine still gets.

 

To sum up, I would not expect at all a behaviour as you‘d have in your Buick, where you can just drop your water levels until the theromometer is not in the water anymore, still not indicating a problem; the air is not that hot (yet). If you are driving, the anbient aircooling also is enough to keep it running for some time without alarming signs. But once you stop and the engines heat goes up such that the water temp dial suddenly jumps to the right extreme, then you have more things to buy than new tubing.

 

 

[-=PHX=-SuperEtendard]

I have tested this some time ago. Depending on the damage to the radiator (a small rifle cal hit or multiple machine gun hits / big cannon hit) you would have rather different leak rates and thus time until engine damage. I think I remember seeing as worst case scenario 4 minutes from radiator leak to engine stoppage, a 109 after receiving multiple 20mm hits to the radiator.

In regards to best case scenario (light damage) I have this from April of last year:
 

Quote

I took a P-51 and I got shot by an I-16 with only ShKAS, my radiator was hit so I ran away and started counting time.

At 8 minutes since the leak started the cooling system began losing efficiency, water temperature climbed to 110°C.
At 16 minutes water temperature was 125°C, radiator was fully opened.
At 19 minutes engine overheat message came up.
At 26 minutes the engine seized.

 

[SCG_motoadve]

8 hours ago, VBF-12_KW said:

BoX feels exceptionally forgiving of coolant leaks right now, to the point where liquid cooled engines seem tougher and more resistant to damage then air cooled engines do.

This is how I feel too about liquid cooled engines in BoX.

[the_emperor]

Yes, indeed damage to to the cooling system does not seem to be as fatal in the game as one would imagine (or as pilots described) for the liquid cooled engines.

Is the radiator cutoff for the BF-109 G/K series modelled in the game.

And does the Spitfire IX/XIV series does have such a cutoff system,too`? I might thing it had, but cant find any cofirmation thus far.

 

Cheers

[PatrickAWlson]

Maybe I'm a wimp, but I would prefer a model that is more on the forgiving side than the harsh side (witness engine seizures on some planes).  As noted in many posts above, the physics of engine seizure due to coolant loss are not only complex but also different from plane to plane.  My guess is that the DM is not that sophisticated.

 

For me, as a gamer, optimum is "let me get home if I break off combat but punish me if I continue to fly like nothing happened".  Exactly what that is or how to model it I don't know.  Not my area of expertise.  When I look at the game in its current state I would agree that it is a bit too lenient.  On the relatively short flights that I fly I can generally ignore a coolant leak, and the AI certainly does as well.  So some tightening of parameters to induce consequences more quickly would be welcome.  Seizing my engine after 60 seconds - not so much.

[ZachariasX]

56 minutes ago, the_emperor said:

Is the radiator cutoff for the BF-109 G/K series modelled in the game.

No.

 

57 minutes ago, the_emperor said:

And does the Spitfire IX/XIV series does have such a cutoff system,too`?

No, because the radiator circuits are not designed that way. In the 109 you have two dedicated water coolers and one dedicated oil cooler. In the later Spitfires, you have just two boxes of a combined arrangement if water coolers, oil cooler and intercooler.

[Hartigan]

#20 is oil cooler , glykol radiators are mounted under the wings

[I./JG52_Woutwocampe]

On some planes coolant leaks have a more devastating effect. A 109 leaking coolant from both radiators has less than 5 minutes. However, overall, I think coolant leaks last too long before the engine goes critical. Im fighting the hurricane all the times in BOM and Ive never seen its engine stop because of a leak, oil or coolant, or both. The Yaks and P-51 too but in a lesser way. 

 

 

[the_emperor]

thank you very much @ZachariasX

I just have the Cliffs of Dover series for reference, but there damage to the radiator or coolant line system (which is fortunately modeled in detail) is a death sentence for every plane that is not over friendly territory  and that make .303s and 7.92mm bullets really scary if you are on the wrong side of the the chanel.

Would be nice have have such a detailed coolant damage/system for the BoX series. As it realy shows the difference beetween the liquid cooled inline engines and their vulvernabilities vs air cooled radial engines.

Cheers

Edited August 8, 2021 by the_emperor