P40 coolant leak

[RedeyeStorm]

Hi guys,

 

I started a career flying the p40 on moscow. On several occasions I got hit and developed a coolant leak. Although I was streaming a bright white plume of coolant I could easily fly back home (roughly 140 km) without noticing any adverse effects. Had I been flying a 109, Yak or Lagg I would never have made it. 

 

Is the air cooling so effictive in a p40 that the need of coolant is minimal? Return journey was around 0 degrees celsius at 2000 feet. It feels like a bug I must say but don't know enough to be certain.

[ACG_KaiLae]

P-40 engine simulation is incorrect in multiple ways. Cooling system is much too effective in many ways.

[Original_Uwe]

5 hours ago, No.615_Kai_Lae said:

P-40 engine simulation is incorrect in multiple ways. Cooling system is much too effective in many ways.

I’ve never had to open it more than a little bit in career so I’m inclined to agree.

[xThrottle_Geek]

Well, without the ability to truly see the specifics of the damage modeling system for coolant leaks.. I would say its hard to say. The bird had a well known reputation for toughness and it could be that the cooling system in this airplane simply operates in such a way as to reflect a certain ruggedness.

[Mitthrawnuruodo]

45 minutes ago, =CAF=xThrottle_Geek said:

Well, without the ability to truly see the specifics of the damage modeling system for coolant leaks.. I would say its hard to say. The bird had a well known reputation for toughness and it could be that the cooling system in this airplane simply operates in such a way as to reflect a certain ruggedness.

The system just isn't modelled correctly. Like most aircraft, the P-40 should eventually overheat from a single hole in the cooling system.

 

In photos of taxiing P-40s, the cowl flaps are almost always fully open. In Il-2, one can leave them closed during an entire mission.

 

 

Edited April 2, 2018 by Mitthrawnuruodo

[Ehret]

There are two water-glycol radiators in the P-40 - perhaps they have own loops or anti-leak valves.

[Mitthrawnuruodo]

21 minutes ago, Ehret said:

There are two water-glycol radiators in the P-40 - perhaps they have own loops or anti-leak valves.

There are two coolant radiators, but they are not independent. 

[56RAF_Roblex]

8 hours ago, Mitthrawnuruodo said:

In photos of taxiing P-40s, the cowl flaps are almost always fully open. In Il-2, one can leave them closed during an entire mission.

 

The same with the A20.  Every time you see a photo of one taxiing it has the input cowl flap open but in the game everyone flies with it closed!  <JK>

 

In all seriousness,   there are many many aircraft that need cooling on the ground but not in flight.   The spitfire can overheat while sitting still with the radiators fully open but can cruise with only 20%   I don't know if they have overmodelled the 'Cowl Closed' cooling of the P40 but a Google search found the official performance tests and they say that the tests were done with the flaps closed,including the tests to see how long they engine could safely run on various engine settings.   

Obviously that does not include flying with a hole in the coolant system but I have seen many different aircraft  in BoX, on both  sides of the war,  fly all the way home  streaming coolant & oil.

Edited April 2, 2018 by 56RAF_Roblex

[danielprates]

Maybe the game models different hole sizes. A small crack should blees less water/oil than an all-through bullet hole, accounting for the diferent times it takes for them to deplete completelly. Still,  they are preasurized,  so it could not take too long in any scenario.

 

One thing is for certain: no engine works for even a couple of seconds with depleted oil,  and coolant liquid is almost as crucial in a non-radial engine. I don't see as being phisicly possible to cool an inline engine with the oil radiator alone,  if the water has ran out. It will overheat badly, in little time. Remeber,  the shutters only control the ammount of air around the radiator: they do not bask the actual engine in a flow of cool air. 

 

So unless the game modelling is all wrong,  one can assume the coolant damage is making some,  but not all,  the coolant to leak. 

Edited April 2, 2018 by danielprates

[Dakpilot]

As with many 'visual' damage indicators I feel that currently some of the effects are exaggerated (or not very proportional) compared with what the 'actual' damage is

 

this can lead to a lot of 'misconception' of what is actually happening in multiple different situations

 

hopefully this (better fidelity) can be addressed in further updates (although is probably a lot of work and more CPU cycles) as it certainly can be an issue and a bit jarring and also lead to WTF situations/comments

 

Cheers, Dakpilot

[xThrottle_Geek]

So, I cannot remember where I got this info, perhaps in the P-40 manual I have at home (I’ll look when I’m home next), but I read somewhere that the cowl flaps (which connect to both water/oil rads) should be closed above 180 mph. I’ve been doing this for months flying it in game and I can confirm that it won’t overheat on cold maps at all in nominal mode and as long as the speed is above that number you can run combat power for the full 5 minutes without overheat problems, though the temp will climb and you’ll need to watch it closer. Of course, on hotter maps it is more sensitive but you can usually crack it barely open, as long as your above 180 mph and it will cool right down. Compared to other aircraft, where rads (oil and water) are open significantly more to keep from overheating, leads me to believe that either the cooling system is particularly effective on the Allison or the engine is just not as sensitive to overtemping. I have little to no time in the P-39 and I know its a slightly different Allison in that one, but does it have the same toughness in regards to overtemping?

[FTC_DerSheriff]

The leaks can be of different size. The visual effect is always the same. You can fly home in a 109 as well if the radiator is only pierced by a small round. Low RPM and throttle helps. And yeah the P-40 isnt overheating at all.

[danielprates]

1 hour ago, =CAF=xThrottle_Geek said:

So, I cannot remember where I got this info, perhaps in the P-40 manual I have at home (I’ll look when I’m home next), but I read somewhere that the cowl flaps (which connect to both water/oil rads) should be closed above 180 mph. I’ve been doing this for months flying it in game and I can confirm that it won’t overheat on cold maps at all in nominal mode and as long as the speed is above that number you can run combat power for the full 5 minutes without overheat problems, though the temp will climb and you’ll need to watch it closer. Of course, on hotter maps it is more sensitive but you can usually crack it barely open, as long as your above 180 mph and it will cool right down. Compared to other aircraft, where rads (oil and water) are open significantly more to keep from overheating, leads me to believe that either the cooling system is particularly effective on the Allison or the engine is just not as sensitive to overtemping. I have little to no time in the P-39 and I know its a slightly different Allison in that one, but does it have the same toughness in regards to overtemping?

 

Even if the engine's appropriate running specs are those you mentioned,  that would be for a perfectly running engine. The OP mentions a situation of coolant loss,  and there is no way you can cool an inline engine on passing air alone!

[Venturi]

The cowling flaps are always opened to the neutral position in flight (or less), the manual means do not open the flaps into the slipstrem (beyond neutral).

Additionally it should overheat quickly like all WW2 aircraft if there is no airflow...

 

[xThrottle_Geek]

Okay, I found my source, but I would like to address one thing first. I am not saying that the engine wont fail without coolant because of its design. I agree that ANY engine absent its mechanism of cooling will fail after some period of time. However, as Sheriff mentioned above, without knowing the extent of the damage it is possible to lower the RPM's way down and pull the manifold pressure way back to the minimum necessary for flight. If the damage is small, and the coolant is leaking slowly (even if the visual effect doesnt change) it is possible to limp quite a ways home. I think that quite often in this game people continue to operate the engine at as high a speed as possible thinking they can cover the ground home faster and thus cause their engine to fail when it could have lasted substantially longer if it had been "babied". Combat does not always allow for this of course. All i can say is that in the sim this airplane seems to have better cooling than many of the other aircraft.

 

Finally, Venturi is correct, it IS a structural limitation on the cowl flaps and not an operational necessity. Anyways, here it is if anyone is interested..

 

Edited April 2, 2018 by =CAF=xThrottle_Geek

[Farky]

On 31. 3. 2018 at 5:44 PM, FFS_RedeyeStorm said:

Hi guys,

 

I started a career flying the p40 on moscow. On several occasions I got hit and developed a coolant leak. Although I was streaming a bright white plume of coolant I could easily fly back home (roughly 140 km) without noticing any adverse effects. Had I been flying a 109, Yak or Lagg I would never have made it. 

 

Is the air cooling so effictive in a p40 that the need of coolant is minimal? Return journey was around 0 degrees celsius at 2000 feet. It feels like a bug I must say but don't know enough to be certain.

 

Are you sure that it was coolant leak and not fuel leak? Because more than often white "smoke" is fuel leak.

 

 

22 minutes ago, =CAF=xThrottle_Geek said:

All i can say is that in the sim this airplane seems to have better cooling than many of the other aircraft.

 

 

It have better cooling than any other aircraft in game and it is wrong. Most of the time, you are not able reach even minimum required temperature of coolant.

 

Here is something from RAF test -

 

 

As we can see, oil temperature in Summer Conditions should be around 75°C, coolant temperature around 100°C. Quick test in game - 2600rpm/34.5inHg (full throttle) at 15 000 ft, Stalingrad Summer and also Kuban Summer, radiator flaps on Neutral - Oil temperature 47°C, Coolant temperature 63°C. Way off.

[RedeyeStorm]

Hey Throttle, babying the engine as you describe I always do, enemies permitting, with any other plane. But the situation that resulted in my post was that I could fly home on nominal engine settings and fully closed cowl flaps and still the engine was running cold.

Farky. Yes I am sure it was coolant. Coolant leak is white, fuel grey. Fuel usually stream from the wing, while coolant out of the fusalage. I saw white and streaming from the fusalage/engine.

[IckyATLAS]

So devs it seems the P40 engine cooling and coolant leak effect needs a small fix. I would support it as I love flying the P40, and indeed the engine seems too good to be true. I prefer the stress and difficulties when having damage to the engine, running rough and with low power. 

Edited April 2, 2018 by IckyATLAS

[Farky]

Got "coolant leak" today in my career mission. It was actually oil leak, since coolant temperature was ok (not even 80°C). It was leaking for few minutes, then it stops for some reason. Anyway, I was unable to keep 2600 rpm /37 inHg, oil temperature was going to reach limits. At some 2300 rpm and 30 inHg, oil temperature was around 80-85°C. Radiator was set on Neutral. My oil pressure was ok all the time, which is rather unfortunate.

[-=PHX=-SuperEtendard]

Btw Farky, do you know which was the ambient temperature in the "temperate summer" and "tropical summer" conditions? In game summer is around 25°C at sea level

[Farky]

If I remember it right, "temperate summer" was 20°C at S.L., "tropical summer" 30°C at S.L..

[Venturi]

On 4/2/2018 at 11:52 AM, Farky said:

 

Are you sure that it was coolant leak and not fuel leak? Because more than often white "smoke" is fuel leak.

 

 

 

It have better cooling than any other aircraft in game and it is wrong. Most of the time, you are not able reach even minimum required temperature of coolant.

 

Here is something from RAF test -

 

 

As we can see, oil temperature in Summer Conditions should be around 75°C, coolant temperature around 100°C. Quick test in game - 2600rpm/34.5inHg (full throttle) at 15 000 ft, Stalingrad Summer and also Kuban Summer, radiator flaps on Neutral - Oil temperature 47°C, Coolant temperature 63°C. Way off.

 

I would just like to cruise at 2600rpm and 34.5" Hg and 243mph ASI...

[=362nd_FS=RoflSeal]

Game treats minimum drag position as radiators closed and i on Stalingrad summer and I got 76 degrees oil and 100 degrees coolant. Seems pretty spot on to me. Apart from the fact that the radiator position is wrong I guess

Edited April 5, 2018 by RoflSeal

[Farky]

23 hours ago, Venturi said:

 

I would just like to cruise at 2600rpm and 34.5" Hg and 243mph ASI...

 

You can cruise at 15 000ft at 2600rpm/34inHg on Stalingrad Summer map and get some 250 mph ASI.

 

21 hours ago, RoflSeal said:

Game treats minimum drag position as radiators closed and i on Stalingrad summer and I got 76 degrees oil and 100 degrees coolant. Seems pretty spot on to me. Apart from the fact that the radiator position is wrong I guess

 

You are absolutely right, minimun drag position is fully closed radiator in game. I got of course same results on Stalingrad summer (78°C oil/100°C coolant) and this is ok, except for radiator position. But (there is always BUT), we should also have fully open radiator in climb. On optimal climb speed (145mph up to 12 000ft, than 135mph), oil temperature should be at 20 000ft around 85°C in summer. In game, you can climb with radiator in neutral and reach 85°C at 20 000ft is not possible even with fully closed radiator (at 130 - 135°C 130 - 135 mph). Cooling of P-40E need some love from developers.

 

 

EDIT: 130-135°C to 130-135 mph

 

Edited April 6, 2018 by Farky

[Venturi]

3 minutes ago, Farky said:

 

You can cruise at 15 000ft at 2600rpm/34inHg on Stalingrad Summer map and get some 250 mph ASI.

 

 

So, it's wrong?

The bird goes too fast (as you just pointed out),

cooling is wrong (as you show - I have been complaining of this for a long time too),

is too heavy (should be ~8100lbs!),

rolls too slowly (in game 4-4.5s for 90deg, should be 3.5-3.75s at 10,000' and 230mph ASI),

has too high a stall speed (95mph, but manual says 90!),

and several parameters of the engine managment are incorrect (MP at 42"Hg/3000rpm until critical altitude per manual - which is 12,000', some 6min!).

 

I suppose I should be happy that it doesn't go into a death spiral when the rudder is kicked anymore.

 

[Farky]

27 minutes ago, Venturi said:

 

So, it's wrong?

The bird goes too fast (as you just pointed out),

 

Since we don't know exact conditions of that test, we can not use it for speed. Btw, as far as I know speed of P-40E in game is spot on, at least at 15 000ft (according RAAF report F.8).

 

For all points you make - write a report with all the evidence to developers.

[=362nd_FS=RoflSeal]

250mph is well within the +-5% that the devs target, so it's not really a problem.

[danielprates]

On 02/04/2018 at 3:09 PM, =CAF=xThrottle_Geek said:

If the damage is small, and the coolant is leaking slowly (even if the visual effect doesnt change) it is possible to limp quite a ways home. I think that quite often in this game people continue to operate the engine at as high a speed as possible thinking they can cover the ground home faster and thus cause their engine to fail when it could have lasted substantially longer if it had been "babied".

 

This is certaily correct.

 

I wonder if there is historical data on how long someone could operate an engine,  in pianissimo parameters,  until it failed. 

 

My idea is,  not too much. Oil and water are pressurized during engine operation. Even the smallest cracks should bleed a lot! On the other hand,  those older engines carried a lot of liquids - if i remember correctly, each lancaster merlin carried 40 liters of oil!  

 

But how much time... that would be guesswork. 15 minutes with a small crack?  30?  More,  less ... ?