reported P-51 engine does not quit when overheated

[amazingme]

  I abused the P-51 for ~15 mins in zoom climbs or turning climbs with speeds even below 100mph, the coolant temp was at max, the oil temp was also at max (rads were on Auto, engine @ mil power). At some point it loses coolant (when reaching 0mph) but after recovering some speed it runs normally again after the coolant temp drops (I've tried that a couple of times).

The track is ~8MB so I uploaded to wetransfer.com: https://we.tl/t-GCJzVTWhUc

L.E. I've tried now with WEP climbing @90mph, the coolant was escaping, engine still running. Track attached.

server-20220825-005845.trk

Cheers!

Edited August 24, 2022 by amazingme

[Andy1966]

I just got home from work, and am updating as I speak. Amazing, it is funny, I was going to do the same thing to the Mustang, so do you mean it seems to be fixed?

[grafspee]

@Andy1966Yes you can stress P-51 and it won't fail immediately after you exceed temp limits  

You can easily take off at mil power w/o warring about blowing engine.

You can climb at mil power w/o blowing engine too when you get speed below 250

Edited August 24, 2022 by grafspee

[Magic Zach]

Additionally if the coolant vapes off but then stops when the temp comes back down, that's the relief valve popping off

Edited August 24, 2022 by Magic Zach

[Andy1966]

 Sweet! that is good to hear

[Schmidtfire]

Fantastic! But why has this fix been reported as a bug?

[grafspee]

Thing that you cant kill your engine due to coolant and oil temp being above limits was reported not whole thing introduced in update

Edited August 25, 2022 by grafspee

[Hobel]

Temperatures +19 Normandie
Radiator Auto
Oil Rich

Test 1 :

60mp and 3000RPm
100kn climb after ~6 min overpressure valve open and coolant is released
The engine dies at  min 23 Coolant seems to have been used up at that moment

test2:

60mp and 3000RPm
100kn climb after ~8 min overpressure valve open and coolant is released
after 17 minutes there is damage which is noticeable by a loss of power from 3000 rpm to 2700 rpm.
after 40min the engine is dead

test3:  60mp and 3000RPm

100kn climb after ~4 min overpressure valve open and coolant is released
after 8 minutes there is damage which is noticeable by a loss of power from 3000 rpm to 2700 rpm.
after 22 no more liquid leaks out engine dies after ~28min

EDIT:

test4:  60mp and 3000RPm
100kn climb after ~3 Engine loses power from 3000 to 2700
Coolant leaks out after 4 minutes
after 11min the engine is dead

test5:  60mp and 3000RPm
100kn climb after ~5 Engine loses power from 3000 to 2700
Coolant leaks out after 6 minutes
after 13min the engine is dead

 

There may already be damage beforehand, but it will not be noticed.
Edit to this:
According to my first observations, there seem to be various problems with the engine or power after exceeding the overload limits.

Edited August 25, 2022 by Hobel

[grafspee]

Apparently engines dies, but you need to wait much longer then it was before.

[Hobel]

vor 39 Minuten schrieb grafspee:

Apparently engines dies, but you need to wait much longer then it was before.

If I had taken the throttle out in between times, the engine would have died much sooner.  How much earlier I test again.

[OLD CROW]

After a LONG time..., almost finally... Mustang has become a pretty fearsome opponent. The fact pilot can completly focus on fighting (both eyes outside the cockpit and 100% the brain lock on the opponenet moves) for a longer time is a great game changer. The other game changer to bare in mind is all the FM-DM modifications implemented in all birds. K4 DM still been "weirdish" in some aspects (here is not the place to mention it) but now hopping on the Mustang and dogfighting  is more pleasant than the pain it has been for too much time.

Let's see if today I have SAME luck as yesterday.... After this update I can do better things than coming here and use the irony when it's necessary... so THANK YOU ED

[grafspee]

I am so happy too, i can wide open this bird for take off with no worries about cooking engine, now every thing feels right and logic, cooler shutter opening speed match the temp changes, before those shutter were miles behind.

[Doughguy]

10 bucks that within one week one comes around "tHiS iS noT reAliSTic and UnFair!"

Im all on my toes until this comes to stable.

 

Edited August 25, 2022 by Doughguy

[Hobel]

I have done some more tests

Military power: For normal conditions, the manual says  5-15 minutes, but these are never fixed, they are meant as a safety measure, so there may or may not always be a little buffer, so it is better not to go over.

Military power 60mp 3000rpm
100kn/185,2km/h

After ~4min, the engine can already suffer irreparable damage, it will run for a while but is basically dead and can fail at any time.
If you take off the throttle ,he also stops immediately and is dead.
it can also cause irreparable damage later on - for me the highest value was ~17min, Damage can still occur that is not noticed beforehand..

 

I think that with these values, the behaviour of the engine is fine - and thus also conforms to what the manual says.
If you're lucky, it goes longer, but that makes the whole thing dynamic and you feel like you have a slightly different engine every time.

For the moment, I see no bug with these values.

 

Therefore, I can only underline what @grafspee@OLD CROWhave said !

 

Edited August 25, 2022 by Hobel

[amazingme]

On 8/25/2022 at 11:05 PM, Hobel said:

I have done some more tests

Military power: For normal conditions, the manual says  5-15 minutes, but these are never fixed, they are meant as a safety measure, so there may or may not always be a little buffer, so it is better not to go over.

Military power 60mp 3000rpm
100kn/185,2km/h

After ~4min, the engine can already suffer irreparable damage, it will run for a while but is basically dead and can fail at any time.
If you take off the throttle ,he also stops immediately and is dead.
it can also cause irreparable damage later on - for me the highest value was ~17min, Damage can still occur that is not noticed beforehand..

 

I think that with these values, the behaviour of the engine is fine - and thus also conforms to what the manual says.
If you're lucky, it goes longer, but that makes the whole thing dynamic and you feel like you have a slightly different engine every time.

For the moment, I see no bug with these values.

 

Therefore, I can only underline what @grafspee@OLD CROWhave said !

 

 

Can you show us where in manual says you can run WEP @ <90mph?

[Hobel]

vor einer Stunde schrieb amazingme:

Can you show us where in manual says you can run WEP @ <90mph?

Sorry, I was referring to Military Power/Take-off the whole time.

Military Power: 3000RPM 60MP 15min
take-off:          3000RPM 60MP 5min
and since the probability of the engine stalling increases sharply from 100kn at 3-5min, I think the whole thing is still OK.

 

at WEP 85kn  (WEP 5min under normal conditions)

 test 1:  the engine dies immediately after 3minutes
test 2: min 3 Motor takes damage min15 Dies
test 3: min 1:30 Motor takes damage min35 Dies
test 4: min 6 Motor takes damage min20 Dies
test 5: min 3:20 Motor takes damage min6 dead

Considering that the engine is allowed to hold 60mp at 3000rpm
for 1 minute at 0kn, these values are fine for 85kn

If the engine is damaged, it will lose a lot of power and seize up when the throttle is taken out.
We could talk about why the engine keeps running for so long after it's been damaged, but maybe it's because it's not making as much power anymore, and that can keep it going for a while?

Maybe more fine tuning will come in the future.

Edited August 27, 2022 by Hobel

[grafspee]

Manual do not put any speed restriction on engine, only for air frame. 

Remember that p51 was tested at 75/3000 with no cooling system modification and cooling was sufficient and climb test was done at 170mph so this iteration of cooling is way better, before there was no way to climb at military power at this speed or in some caces 46/2700 was still too much to hold safe temps.

Edited August 28, 2022 by grafspee

[Hobel]

vor 6 Minuten schrieb grafspee:

Manual do not put any speed restriction on engine, only for air frame.

you mean me?

 I would consider the context of take-off power 5min limit as a kind of "speed restriction" for the engine.

Edited August 28, 2022 by Hobel

[grafspee]

2 minutes ago, Hobel said:

you mean me?

 I would consider the context of take-off power 5min limit as a kind of "speed restriction" for the engine.

 

Not you i was commenting about where manual says that wep can be ussed below 90kt

[grafspee]

Those time limits on engine are  for engine life time, because engine was designed to work through many hours of flight so manufacturer says if you want this engine run fine through 600hours you need to do this and this. Exceeding time limits do not mean immediate failure.

Edited August 28, 2022 by grafspee

[Hobel]

vor 48 Minuten schrieb grafspee:

Those time limits on engine are  for engine life time, because engine was designed to work through many hours of flight so manufacturer says if you want this engine run fine through 600hours you need to do this and this. Exceeding time limits do not mean immediate failure.

 

yes of course that's what i mean
that's why you should not hold 3000rpm/60mp for more than 5min after take-off.

in DCS take-off power should hardly play a role.

 

 

[Gunfreak]

For someone not that into the finer details. 

 

Can someone explain to me like I'm a 37 year old child.

How does this affect how I fly.

 

I've been told. Never do WEP unless you're over 200mph and max 15 minutes. 

You can do 2700rpm and 46 MP continuously as long as you are over 170mph

 

What exactly has this update done to chance this?

[grafspee]

15 minutes ago, Gunfreak said:

For someone not that into the finer details. 

 

Can someone explain to me like I'm a 37 year old child.

How does this affect how I fly.

 

I've been told. Never do WEP unless you're over 200mph and max 15 minutes. 

You can do 2700rpm and 46 MP continuously as long as you are over 170mph

 

What exactly has this update done to chance this?

Those advices were created by players who have flown P-51 in DCS, and after many trails this conclusion was established, those speed limits were determined by cooling system which in previous iteration wasn't able to provide enough cooling for engine below those speeds

Recently Open Beta DCS received new cooling physics with coolant boiling simulation and right now P-51 cooling system is very much improved and this speed problem is pushed away.

Right now you can climb mil/wep power at rated 175mph for best climb.

Right now you can put cooling shutters in AUTO mode just like every single P-51 manual states, with out warring about cooking your engine during take off or during fierce combat.

But you need to be on OPEN BETA version to experience it, if you are using STABLE VERSION old cooling physics is still there so old speed limits are still valid.

Maybe it is bad idea but, i think it would be good thing to tag Posts Open/Stable, so ppl would not get confused, many players use Stable only  

Edited August 28, 2022 by grafspee

[Gunfreak]

7 minutes ago, grafspee said:

Those advices were created by players who have flown P-51 in DCS, and after many trails this conclusion was established, those speed limits were determined by cooling system which in previous iteration wasn't able to provide enough cooling for engine below those speeds

Recently Open Beta DCS received new cooling physics with coolant boiling simulation and right now P-51 cooling system is very much improved and this speed problem is pushed away.

Right now you can climb mil/wep power at rated 175mph for best climb.

Right now you can put cooling shutters in AUTO mode just like every single P-51 manual states, with out warring about cooking your engine during take off or during fierce combat.

But you need to be on OPEN BETA version to experience it, if you are using STABLE VERSION old cooling physics is still there so old speed limits are still valid.

Maybe it is bad idea but, i think it would be good thing to tag Posts Open/Stable, so ppl would not get confused, many players use Stable only  

 

So now I have to actually watch the temperature gauges and fly accordingly instead of following a "recipe"? Think I'm gonna try the blue nose bastard campaign again.  Gave up on mission 2. As I couldn't keep up with the AI flight 

[grafspee]

I just recall one thing, in manual of P-51 in part dedicated cold weather, there is dedicated shutter which had to be installed in cold weather time, in winter for example, i think we will need that sooner or later.

Edited August 28, 2022 by grafspee