P-39 Airacobra: How to use Military Power 42inchHg / 3000RPM for ca. 15min. without overheating?

[kraut1]

UPDATED CURRENT STATUS: INCONCLUSIVE: WHEN I WANTED TO RECORD A TRACK MILITARY MODE SUDDENLY WORKED WITH SAME SETTINGS, I WILL DO FURTHER CHECKS.

 

Hi All,

I am currently testing some "Port Moresby intercept missions" for my campaign.

To intercept the japanese Bombers (Ju88), flying in 5000m altitude, I tried to climb with realistic settings in Military Mode:

-Water Cooler Shutter: full open.

-Oil Cooler: Full Open

-mixture: Full Rich

-Manifold pressure: 41...42 inch Hg / 3000RPM

-Ambient Temperature according Quick mission: 25°C

 

After ca. 7:30 minutes a white steam trail is shown, what indicates that the engine is damaged.

 

What do I wrong?

It' would not be a problem for me, if I could use military power only for ca. 12...14 minutes, but ca 7:30 minutes until the engine is damaged is just the half of 15minutes that should work.

Many thanks in advance!

 

 

 

My settings during test flight:

 

 

 

Edited March 13, 2024 by kraut1
UPDATED CURRENT STATUS: INCONCLUSIVE: WHEN I WANTED TO RECORD A TRACK MILITARY MODE SUDDENLY WORKED WITH SAME SETTINGS, I WILL DO FURTHER CHECKS.

[BlitzPig_EL]

The in game P39 suffers from the same glass jaw engine limits as the P40 did until the last update gave us a more realistic engine model.   The best you can probably do with the current modeling is to run the engine no higher than 2800rpm, and probably closer to 2600rpm.  It's gaming the game, but it's the only way to make the V-1710 live as modeled.

[kraut1]

10 hours ago, BlitzPig_EL said:

The in game P39 suffers from the same glass jaw engine limits as the P40 did until the last update gave us a more realistic engine model.   The best you can probably do with the current modeling is to run the engine no higher than 2800rpm, and probably closer to 2600rpm.  It's gaming the game, but it's the only way to make the V-1710 live as modeled.

 

UPDATED CURRENT STATUS: INCONCLUSIVE: WHEN I WANTED TO RECORD A TRACK MILITARY MODE SUDDENLY WORKED WITH SAME SETTINGS, I WILL DO FURTHER CHECKS.

 

Thanks for your answer,

Yes, I already flew with the P40 last year with ca.2800 rpm because of frequent engine trouble.

I will try to get optimized settings with rpm 2600 - 2800 for P-39 too.

Climbing with 2600rpm / 37.5inch Hg is still more or less acceptable.

Fighting against the La5 / Zeros is possible too, but sometimes the engine is damaged.

But I will report it as an Issue to be corrected.

UPDATED CURRENT STATUS: INCONCLUSIVE: WHEN I WANTED TO RECORD A TRACK MILITARY MODE SUDDENLY WORKED WITH SAME SETTINGS, I WILL DO FURTHER CHECKS.

 

Edited March 13, 2024 by kraut1

[FeuerFliegen]

This is one of those planes that doesn't need a fake engine timer; it naturally prevents you from running the engine longer than the time limits simply through overheating.  

 

Which is the way I think it should be; many planes suggested time limits on high power settings were to prevent overheating.

Edited March 14, 2024 by FeuerFliegen

[kraut1]

For me currently I don't understand the test results:

Yesterday morning the engine was damaged after ca... 5..7 minutes during and Military Mode low speed climbing with settings:

-Water Cooler Shutter: full open.

-Oil Cooler: Full Open

-mixture: Full Rich

-Manifold pressure: 41...42 inch Hg / 3000RPM

-Ambient Temperature according Quick mission: 25°C

And when I wanted to record a track with the same settings suddenly in Military Mode the P-39 engine did not overheated.

The test mission was on the same map (Lapino Summer) and both Quick Mission and Test Mission with the same ambient temperature.

The only thing I changed in the reality settings was to display the "Instrument panel" for the 1st flight to record a track:

But even after I deactivated this again Military Mode is still working (What is good of course).

 

My question:

Which engine settings / game settings that have impact I could have overseen?

I have considered: Water Cooler Shutter, Oil Cooler Shutter, mixture, constant speed rpm, Manifold Pressure, ambient temperature,

and always the same style of flight: whole flight with engine in Military Mode, constantly climbing with 140...160mph. And when I reached the maximum high of the supercharger I I stopped climbing when max. Manifold Pressure dropped to 42inchHg and flew some time at the same level.

 

[Charon]

I don't know. My best guess is that this was just operator error -- that in your first flight, you only had your water radiator shutter partially open, and didn't realize it, and this is why you haven't been able to reproduce it.

 

I lead a P-39 flight last night with some friends, and we did have one plane drop out due to overheating on the way to 12k ft, similar to what you describe. We were only pulling 35" and 2600 RPM, so I assume it must have been an error with the radiator, but we were not able to determine the exact problem.

[CountZero]

Oil radiator you should have at 40% ( min drag position ) and it will not need adjusting even on summer maps or agresive climbs

Water rad best position is 60% (min drag position ) but on summer maps youll have to have it open full or 75% if not climbing

Mixture you should have on auto ritch  , dont use full 

 

i check engine timer, its 15min ( message showed up at exact time it should) on 42inch and 3000rpm on any alt, so that was not problem you can safely use them

 

why engine broke i dont know, only time i expirianced it was when being agresive with rpm or throttle , or overheating was to long

[FuriousMeow]

On 3/13/2024 at 10:11 PM, FeuerFliegen said:

 

Which is the way I think it should be; many planes suggested time limits on high power settings were to prevent overheating.

 

No they weren't. They were to prevent damage to valves, cylinder heads, gaskets, bearings and other parts of the engine internals that could be damaged when exposed to long periods of high pressures or high revolutions. Simple fact is, we have timers because there's a new engine every time. There isn't a real easy solution to this other than getting rid of the timers and everyone just zooms around at full throttle.

[CountZero]

12 hours ago, FuriousMeow said:

 

No they weren't. They were to prevent damage to valves, cylinder heads, gaskets, bearings and other parts of the engine internals that could be damaged when exposed to long periods of high pressures or high revolutions. Simple fact is, we have timers because there's a new engine every time. There isn't a real easy solution to this other than getting rid of the timers and everyone just zooms around at full throttle.

easy solution is to fix bugged messages that inform player when engine timer expired or recovered, then if they work like all other techchat mesages when techchat is only on , players would not be wondering why their engine blow up with no reason.

 

If you add mehanick that was not this extreme as it is in game, you need to at minimum make player informed when you exactly wont player to stop using it, and thats not working now.

 

If in real airplanes engine restrictions were this extreme like in game real planes would have alarm in cockpit (sound or light) to warn them that they are now in random fail mode. We in game have techchat with 1000s of unnneccesary messages, but ones that help player with un-existing thing, we have buged for years.

 

So yes there is simple solution.

 

Also yaks or laggs dont have timers and we dont see ppl flying full power all the time, FUEL and HEAT ristiricks this, and it would on all other airplanes... making option timers offf would not sudenly make players fly 100% all the time in 109 or spit...

 

I could just imagine what mess it would be if game devs decided that they dont wont to include icons in game as real pilots didnt have icons, to help old blined players play game. 

 

real airplanes also didnt have best frame conditions like we have in game, but you dont see devs simulate random frame brakings that were reported in real war... or gun jams that were famous for jamming under high Gs , or poor labor to manufacture or sabotage building of airplanes... and so on.. but problem is engine is new like other 80 % of airplane, and we need to simulate not so offten part of ground mehancics problems . I do not see players asking for random hull failuers , jams, or so on.. but somehow we should be ok with some airplanes having random engine fails, and not have option to turn it on or off.

Edited March 16, 2024 by CountZero

[FeuerFliegen]

On 3/15/2024 at 7:52 PM, FuriousMeow said:

 

No they weren't. They were to prevent damage to valves, cylinder heads, gaskets, bearings and other parts of the engine internals that could be damaged when exposed to long periods of high pressures or high revolutions. Simple fact is, we have timers because there's a new engine every time. There isn't a real easy solution to this other than getting rid of the timers and everyone just zooms around at full throttle.

 

 

I didn't say that this is the only reason all planes had suggested time limits on certain engine power settings; I'm saying that overheating was a reason for them on many planes.  The MW50 Bf109s specifically state in their manual that the reason for a 10 minute limit is to allow the engine to cool down.  Yes I know that there were also many planes that had time limits to prevent damage to internal engine parts, but much of this is also due to excessive heat.

On 3/15/2024 at 6:09 PM, CountZero said:

Mixture you should have on auto ritch  , dont use full

 

While the majority of the time you should be on auto rich, you are supposed to use full mixture for emergency mode.

[Charon]

15 minutes ago, FeuerFliegen said:

While the majority of the time you should be on auto rich, you are supposed to use full mixture for emergency mode.

I wonder where that instruction comes from. The manual I have for the P-39K-1/L-1 doesn't seem to have such a procedure, or to mention the 60" limit at all.

[LukeFF]

On 3/16/2024 at 6:13 PM, FeuerFliegen said:

While the majority of the time you should be on auto rich, you are supposed to use full mixture for emergency mode.

 

On 3/16/2024 at 6:30 PM, Charon said:

I wonder where that instruction comes from. The manual I have for the P-39K-1/L-1 doesn't seem to have such a procedure, or to mention the 60" limit at all.

 

Per one of the P-40 manuals I have seen, full rich was only to be used when there was a malfunction in the other fuel mixture settings. 

[Charon]

27 minutes ago, LukeFF said:

Per one of the P-40 manuals I have seen, full rich was only to be used when there was a malfunction in the other fuel mixture settings. 

Yes, that's how I typically expect full rich to be used.

 

But the in-game pilot's notes say this:

• There is War Emergency power mode. To engage it, move the throttle to max forward position and set the mxiture control to Full Rich (move it 90% forward to engage the Take-Off mode).

The 1944-04-15 revision of the P-39K/L Pilot's Flight Operating Instructions gives 51" as the maximum power setting (Take Off Power); unlike the P-40 it has a manifold pressure regulator so ordinarily I would expect 51" to be what the regulator would give at full throttle. For it to reach 60" (the maximum possible in-game) someone must have altered the regulator. Is there a T.O. for this?

 

https://user.fm/files/v2-f4dc4917d47df33ccd802b425c97b8b5/p-39-operation.pdf

[LukeFF]

23 hours ago, Charon said:

Yes, that's how I typically expect full rich to be used.

 

But the in-game pilot's notes say this:

• There is War Emergency power mode. To engage it, move the throttle to max forward position and set the mxiture control to Full Rich (move it 90% forward to engage the Take-Off mode).

The 1944-04-15 revision of the P-39K/L Pilot's Flight Operating Instructions gives 51" as the maximum power setting (Take Off Power); unlike the P-40 it has a manifold pressure regulator so ordinarily I would expect 51" to be what the regulator would give at full throttle. For it to reach 60" (the maximum possible in-game) someone must have altered the regulator. Is there a T.O. for this?

 

https://user.fm/files/v2-f4dc4917d47df33ccd802b425c97b8b5/p-39-operation.pdf

 

@=FB=VikS or @Gavrick would need to be the ones to answer this. 

[ZPA_Malan]

I hope there's a chance of the p39 getting a similar Allison update to the p40. It climbs like a rock and bleeds energy like a feather, but it does fly like dream in a dive, and is hypothetically fast on the deck at full power. It'd be interesting if still challenging to fly it in a Kuban career (or that port moresby campaign) If that power could reliably be used to extend or escape - but with an automatically imploding engine its a very tricky plane to stick with.

Edited March 22, 2024 by ZPA_Malan

[FuriousMeow]

On 3/16/2024 at 8:06 AM, CountZero said:

Also yaks or laggs dont have timers and we dont see ppl flying full power all the time, FUEL and HEAT ristiricks this, and it would on all other airplanes... making option tim

 

 

Have you looked at the RPM and MP of the Yaks, LaGGs and Las? Their full power is the nominal power of other planes. So they are running engine settings exactly the same as others where there is no timer. This is a tired response and completely ignores the engine operating range differences.

[FuriousMeow]

On 3/16/2024 at 9:13 PM, FeuerFliegen said:

 The MW50 Bf109s specifically state in their manual that the reason for a 10 minute limit is to allow the engine to cool down.  Yes I know that there were also many planes that had time limits to prevent damage to internal engine parts, but much of this is also due to excessive heat.

 

 

 

Most engine limitations were not due to excessive heat, the high rpm and MP are the reason. That could lead to high cylinder head temps, which wouldn't be something resolved by opening shutters but just by running lower RPMs and MP. MW50 and water methanol brought their own heat because they allowed the engines to run even higher, but heat wasn't the primary reason for limiting how long high RPM and MP could be used.

 

An engine can be run at high RPMs and blow before heat is an issue.

Edited March 22, 2024 by FuriousMeow

[[CPT]Crunch]

It was due to design method of the engine connecting rods.  Russian method is different, much lower overall RPM's at higher torque compared for those same RPM's against it's counterparts.  The rods of two pistons share the same bearing but not exactly independently.  The draw back is this design puts limits on the maximum allowed RPM's that can be tolerated.  But when your industrial base is shaky and put on the move it's the best choice with ease of production.

The American and British design using an overlapping fork rod, allowing for much higher RPM's for producing greater power output for limited time at maximums.

And likely the best combo, pretty much the same as western allies except the Germans used ball bearings improving the sustained maximum times of peak output.  Ball bearings reduced heating, until they didn't toward the end of the war.  It takes a high level of industry and machining tech to produce, something Germany was rapidly losing.  

And that's why your Russian planes can run unlimited, the design already built in a limit, on the RPM's. 

[[CPT]Crunch]

Good power output but the engines tended to end up on the heavier end of the scale, sort of negating that advantage, why they spent so much difference on the effort for lite air frame designs.

[kraut1]

Thanks very much for your many answers and the interesting discussion!

I am now able to fight with the P-39 with realistic settings vs Zero (La-5 FN) and the Oscar (La-5 S38).

Additionally I am testing a small mod which adds some additional air drag to the La5s to slow down them a bit to the real speeds of the japanese planes.

[ZPA_Malan]

Wait, it's possible to mod upgrades to a plane, or does it change the stats universally? If the Allison engine upgrade now available for the p40 could be copy/pasted to the p39...that would be a total game-changer.

[LukeFF]

20 hours ago, ZPA_Malan said:

Wait, it's possible to mod upgrades to a plane, or does it change the stats universally? If the Allison engine upgrade now available for the p40 could be copy/pasted to the p39...that would be a total game-changer.

 

It's a little bit more complicated than that. ?

[kraut1]

On 3/27/2024 at 4:51 PM, LukeFF said:

 

It's a little bit more complicated than that. ?

Altogether seen for me the P-39 with realistic settings is okay...

 

[ZPA_Malan]

Nice shooting kraut1! you seem to have it figured out, I reckon you're doing those pitchbacks to gain altitude fast? I'll have to give that a try.

 

side note - personally this is the first plane with aileron trim I've flown, and have found the following settings useful as a rule of thumb to keep level without fiddling too much in combat:

nominal power (-10% aileron trim)

combat power (-15% aileron trim)

Takeoff/WEP (-20% aileron trim)

 

Edit: also would recommend messing with joystick sensitivity and upping the noise filter if you have a cheap joystick like me - it goes  a long way towards effective aiming and preventing surprise stalls.

 

On 3/27/2024 at 10:51 AM, LukeFF said:

 

It's a little bit more complicated than that. ?

I imagine that the AI has to be programmed to use it, have it available in career and so on? Even in unbreakable the p39 becomes more forgiving but not OP over kuban. Still requires more discipline than a yak with energy management, trim, overheating, sticking to BnZ etc - as it should.  Hopefully something is in the cards for future updates. ?

Edited April 6, 2024 by ZPA_Malan

[kraut1]

24 minutes ago, ZPA_Malan said:

Nice shooting kraut1! you seem to have it figured out, I reckon you're doing those pitchbacks to gain altitude fast? I'll have to give that a try.

 

 

Hi, the "pitchbacks", as you call them, that I I did after the 2 kills. Yes, I did this to get some altitude, and when I am at the highest point I throttle back and open the cooler to cool down the engine. But I have to admit from my experience that it is very often dangerous to climb after a kill, because often AI enemies will follow and shoot... If you just want to survive to fly another mission, I think best is after an air victory to dive with maximum speed away from the combat zone at low level, to watch carefully if really no-one follows you and in safe distance to climb again.

In all of my missions I have installed my wingmen warning messages, that means, if my, in this case US comrades, are closer than 2,5km they will inform / warn  me with some 70% to 90% probabillity about nearby enemies.  To fly together with wingmen is  from my point of view one of the most importent aspects of air combat.

 

Her an example, were the pitchback was a wrong desicion:

(see critical situation at 05:45)

https://youtu.be/gRjVNJt3ao0

 

[LukeFF]

20 hours ago, ZPA_Malan said:

I imagine that the AI has to be programmed to use it, have it available in career and so on? Even in unbreakable the p39 becomes more forgiving but not OP over kuban. Still requires more discipline than a yak with energy management, trim, overheating, sticking to BnZ etc - as it should.  Hopefully something is in the cards for future updates. ?

 

It's things like that, yes. Hopefully time will allow for these changes to be made.