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Greetings everyone.

 

A few questions about the IL2 engine management. 

 

It is said in the aircraft specifications that the boost engages when the mixture is set to 100%. However I noticed that the boost engages when you set the rpm to 100% wether the mixture is a 100% or not. Is there something that escapes me?

 

The aircraft specs also state that the mixture becomes automatic if the lever is set to 50% but I totally fail to see any difference if I set the mixture to 50% or 75% in the engine behaviors. It doesnt look to me that the mixture will adjust automatically according to altitude, rpm and throttle even its set flush to 50%.

 

Thanks, and btw Im relatively new to complex engine management, and I actually LOVE it. I have been reading about it a lot and now I decided to go for it. I may have many questions about all the intricacies though! ;)

 

 

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8 minutes ago, I./JG52_Woutwocampe said:

The aircraft specs also state that the mixture becomes automatic if the lever is set to 50% but I totally fail to see any difference if I set the mixture to 50% or 75% in the engine behaviors.

 

I don't fly the IL-2 much, and I doubt I've taken one above 3k meters where leaning the mixture out becomes more important. However, I think an automatic mixture is there to keep the engine performance the same at any altitude. The place where it would be most notable would be at higher altitudes where excess fuel would cause a vapor trail and/or excess fuel consumption during a mission. If at low altitudes and using auto-rich setting you shouldn't notice anything, as the engine likes rich mixture there.

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1 hour ago, cardboard_killer said:

 

I don't fly the IL-2 much, and I doubt I've taken one above 3k meters where leaning the mixture out becomes more important. However, I think an automatic mixture is there to keep the engine performance the same at any altitude. The place where it would be most notable would be at higher altitudes where excess fuel would cause a vapor trail and/or excess fuel consumption during a mission. If at low altitudes and using auto-rich setting you shouldn't notice anything, as the engine likes rich mixture there.

 

Yeah, I guess I'll just use full mixture setting under 3000m alt like with the Yaks and thats it. If memory serves, I also think that using full mixture setting helps cooling the engine.

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18 minutes ago, I./JG52_Woutwocampe said:

Yeah, I guess I'll just use full mixture setting under 3000m alt like with the Yaks and thats it.

 

Well, if you need to save fuel, you'll want to lean it out during non-combat, but otherwise probably not a bad idea.

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59 minutes ago, cardboard_killer said:

 

Well, if you need to save fuel, you'll want to lean it out during non-combat, but otherwise probably not a bad idea.

 

Yep, sounds reasonnable. I rarely find myself short of fuel in my IL2 career but for the sake of realism you might still wanna avoid wasting fuel for no good reason.

 

But I still dont understand why the aircraft specs link the boost to the mixture setting when in-game it activates when rpm is set to max regardless to the actual mixture setting...

 

 

 

 

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1 hour ago, I./JG52_Woutwocampe said:

 

But I still dont understand why the aircraft specs link the boost to the mixture setting when in-game it activates when rpm is set to max regardless to the actual mixture setting...

With any plane, if you exceed the nominal settings in any respect (RPM, manifold pressure, etc.) you'll get the notice in the technochat to warn you. That doesn't mean you're at full boost; in this case, you've exceeded max continuous RPM but haven't actually engaged the boost. You should (?) get a little more power if you push both RPM and mixture to full.

2 hours ago, I./JG52_Woutwocampe said:

 

Yeah, I guess I'll just use full mixture setting under 3000m alt like with the Yaks and thats it. If memory serves, I also think that using full mixture setting helps cooling the engine.

FYI, Yaks perform best with about 70% mixture (at least, they did when I last tested). You can leave it there up to about 4k altitude before you need to worry about leaning.

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5 hours ago, I./JG52_Woutwocampe said:

Greetings everyone.

 

A few questions about the IL2 engine management. 

 

It is said in the aircraft specifications that the boost engages when the mixture is set to 100%. However I noticed that the boost engages when you set the rpm to 100% wether the mixture is a 100% or not. Is there something that escapes me?

 

The aircraft specs also state that the mixture becomes automatic if the lever is set to 50% but I totally fail to see any difference if I set the mixture to 50% or 75% in the engine behaviors. It doesnt look to me that the mixture will adjust automatically according to altitude, rpm and throttle even its set flush to 50%.

 

Thanks, and btw Im relatively new to complex engine management, and I actually LOVE it. I have been reading about it a lot and now I decided to go for it. I may have many questions about all the intricacies though! ;)

 

Hope this helps: with all the Il-2s and the MiG-3 (which all use the AM-38 engine), setting mixture to the max will allow you to achieve higher RPMs and boost pressure when you also set the prop RPM and throttle to the max. When you set the mixture below the max level, the engine will only be capable of generating max continuous power.

Edited by LukeFF
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1 hour ago, gorice said:

With any plane, if you exceed the nominal settings in any respect (RPM, manifold pressure, etc.) you'll get the notice in the technochat to warn you. That doesn't mean you're at full boost; in this case, you've exceeded max continuous RPM but haven't actually engaged the boost. You should (?) get a little more power if you push both RPM and mixture to full.

FYI, Yaks perform best with about 70% mixture (at least, they did when I last tested). You can leave it there up to about 4k altitude before you need to worry about leaning.

 

Thanks for your reply. Lets talk about the Yak. So you are saying that, even within the supercharger's first gear (low altitude), I will get as much power and result from my engine at 70% mixture for a lower fuel consumption than I would at 100%?

 

Still about the Yak, I dont get any BOOST engaged technochat message even if Im at 100% rpm and throttle. Correct me if Im wrong but such settings cannot be held in a continous way without any risk therefore a boost message should appear in the technochat according to what you say, even if its technically not a real boost that is engaged?

46 minutes ago, LukeFF said:

 

Hope this helps: with all the Il-2s and the MiG-3 (which all use the AM-38 engine), setting mixture to the max will allow you to achieve higher RPMs and boost pressure when you also set the prop RPM and throttle to the max. When you set the mixture below the max level, the engine will only be capable of generating max continuous power.

 

Makes sense. So even if I get the boost engaged message in the technochat at mixture 75%, I should still pump the mixture to 100% to get the optimal boost out of the AM-38.

 

Aaannnd the MiG3 uses the AM-35. Only a few used the AM-38 which of course yielded better low alt performances for but they decided to give full priority to the IL2 for this engine with good reason so the AM 38 MiG was never produced in a large scale. But I know you already know that ;).

Edited by I./JG52_Woutwocampe
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12 minutes ago, I./JG52_Woutwocampe said:

Aaannnd the MiG3 uses the AM-35. Only a few used the AM-38 which of course yielded better low alt performances for but they decided to give full priority to the IL2 for this engine with good reason so the AM 38 MiG was never produced in a large scale. But I know you already know that ;).

 

Whoops! My goof, yes.

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10 minutes ago, LukeFF said:

 

Whoops! My goof, yes.

 

Mikulin were requested to stop producing AM-35s and only AM-38s, full priority to the sturmovik. Logical since the MiG3 was mostly useless on the Eastern front. If memory serves it has only a single speed supercharger optimized for high alt which kind of explains the less than stellar low alt performances. 

 

Its a bit unfortunate though that there was no use at all for an high alt interceptor for the VVS because I remember reading about some MiG prototypes which had high alt performances matching the Ta152 but earlier.

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1 hour ago, I./JG52_Woutwocampe said:

 

Thanks for your reply. Lets talk about the Yak. So you are saying that, even within the supercharger's first gear (low altitude), I will get as much power and result from my engine at 70% mixture for a lower fuel consumption than I would at 100%?

 

Still about the Yak, I dont get any BOOST engaged technochat message even if Im at 100% rpm and throttle. Correct me if Im wrong but such settings cannot be held in a continous way without any risk therefore a boost message should appear in the technochat according to what you say, even if its technically not a real boost that is engaged?

Yak doesn't have a 'boost' setting, it can run on full power until it overheats or runs out of fuel.

 

For the mixture, my guess is that 100% is for startup or something. A translated manual I read once seemed to say that ground crew should set the mixture for flight, and the pilot shouldn't touch it until over 4 or 4.5 km, at which point they should lean until they start to lose power, then increase slightly for the right setting.

 

I haven't actually tested mixture in all the Yaks; it could be that I'm missing something.

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21 minutes ago, gorice said:

Yak doesn't have a 'boost' setting, it can run on full power until it overheats or runs out of fuel.

 

For the mixture, my guess is that 100% is for startup or something. A translated manual I read once seemed to say that ground crew should set the mixture for flight, and the pilot shouldn't touch it until over 4 or 4.5 km, at which point they should lean until they start to lose power, then increase slightly for the right setting.

 

I haven't actually tested mixture in all the Yaks; it could be that I'm missing something.

 

I checked a few vids from Sheriff and he also says that under 4000m you dont need to mind the mixture at all, leave it at 100% and it'll be alright. The Yak 1 that is. 

 

For the IL2 well I guess I'll leave it to 50% mixture all the time unless I wanna get a full boost then switch up to 100% mixture to go with 100% rpm and throttle for a short while.

 

And fully close the oil radiator shutters for better protection from AAA while I strafe ;).

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2 hours ago, I./JG52_Woutwocampe said:

 

I checked a few vids from Sheriff and he also says that under 4000m you dont need to mind the mixture at all, leave it at 100% and it'll be alright. The Yak 1 that is.

 

OK, this was bothering me, so I went and did some tests.

 

All planes tested on Kuban Autumn over the sea. Altitude 300 meters. Radiators 50/50. 1st supercharger gear. All speeds IAS from the UI dashboard.

 

Yak-1 s.69

100% mixture = 510 kph

75% = 513

50% = 508

 

Yak-1 s.127

100% = 520

75% = 523

50% = 518

 

Yak-7b

100% = 523

75% = 527

50% = 521

 

So it really does look like 75% (or 70%, which seems to give the same performance) is the way to go.

 

Fun fact: I ran the Yak-1s at 86% RPM, because that's what you're supposed to do for ideal performance at sea level (it nets you a couple of kph), but the Yak-7 also benefits from lower RPMs (not included in these figures, but it does give a small benefit).

Edited by gorice
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1 hour ago, gorice said:

OK, this was bothering me, so I went and did some tests.

 

All planes tested on Kuban Autumn over the sea. Radiators 50/50. 1st supercharger gear. All speeds IAS from the UI dashboard.

 

Yak-1 s.69

100% mixture = 510 kph

75% = 513

50% = 508

 

Yak-1 s.127

100% = 520

75% = 523

50% = 518

 

Yak-7b

100% = 523

75% = 527

50% = 521

 

So it really does look like 75% (or 70%, which seems to give the same performance) is the way to go.

 

Fun fact: I ran the Yak-1s at 86% RPM, because that's what you're supposed to do for ideal performance at sea level (it nets you a couple of kph), but the Yak-7 also benefits from lower RPMs (not included in these figures, but it does give a small benefit).

 

Interesting, thanks. What altitude? Were you close to the critical altitude of the supercharger's 1st gear? 

 

I really wonder why 75% yields the best result at low alt for the Yak. Intriguing.

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2 minutes ago, I./JG52_Woutwocampe said:

 

Interesting, thanks. What altitude? Were you close to the critical altitude of the supercharger's 1st gear? 

 

I really wonder why 75% yields the best result at low alt for the Yak. Intriguing.

Sorry, forgot to mention, it was 300 meters.

 

Fully rich isn't necessarily the most effective mixture for running a plane. Most planes seem to have the option of running richer for starting the plane, different weather conditions, or something like that.

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55 minutes ago, gorice said:

Sorry, forgot to mention, it was 300 meters.

 

Fully rich isn't necessarily the most effective mixture for running a plane. Most planes seem to have the option of running richer for starting the plane, different weather conditions, or something like that.

 

Just for the record, I just flew a Yak 1 mission in my Stalingrad career and decided to go with 75% mixture. I dont know if its a coincidence or not but Im gonna have to say that I felt an excellent performance output from my engine only tweaking rpm a bit from time to time and throttling while leaving mixture at 75% all the way. I shot down 4 Gustavs and an Emil. I even felt I had a speed advantage over the Gustavs most of the fight. Impressive result man. In my next mission I definately will be using 75% mixture after takeoff. ;) Thanks for the tip.

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8 hours ago, gorice said:

OK, this was bothering me, so I went and did some tests.

 

All planes tested on Kuban Autumn over the sea. Altitude 300 meters. Radiators 50/50. 1st supercharger gear. All speeds IAS from the UI dashboard.

 

Yak-1 s.69

100% mixture = 510 kph

75% = 513

50% = 508

 

Yak-1 s.127

100% = 520

75% = 523

50% = 518

 

Yak-7b

100% = 523

75% = 527

50% = 521

 

So it really does look like 75% (or 70%, which seems to give the same performance) is the way to go.

 

Fun fact: I ran the Yak-1s at 86% RPM, because that's what you're supposed to do for ideal performance at sea level (it nets you a couple of kph), but the Yak-7 also benefits from lower RPMs (not included in these figures, but it does give a small benefit).


@I./JG52_Woutwocampe
Since I made the video the mixture mechanics got an update. 70-80% equals now the 100% from before. You can kept it there until 4k.

Edited by DaVeryRedSheriff
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5 hours ago, SCG_FeuerFliegen said:

What about winter maps?  Have you done any testing on that?  I would think that since the air is denser, you'd want a higher amount of fuel to match the additional air.  Same question for summer maps.


I havent done any testing to that extent, in general you are right, but I wouldnt break your head over this. the speed differences of slightly imperfect mixture settings aren't really a deciding factor.
I would only recomment not to go full rich. From 0-4km use 70-80%. More like 70 for summer and around 80 for winter maps.
The engine is smoking a little when the mixture is good for speed. No smoke at all is usually a sign of a slightly too lean mixture.
All this is for speed ofc, there are other considerations, like engine temperatures which benefit from a high mixture.


 

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On 1/12/2021 at 3:28 PM, I./JG52_Woutwocampe said:

Makes sense. So even if I get the boost engaged message in the technochat at mixture 75%, I should still pump the mixture to 100% to get the optimal boost out of the AM-38.

 

Try watching the manifold pressure gauge on the instrument panel when you adjust the mixture setting.  Set max throttle and mixture at 75%, then increase the mixture: if there is even more power to be had then you should see the manifold pressure gauge needle rise as you enrich the mixture.  If the mixture is richer than max power then you will see the MP needle stop rising and you will see more smoke (unburned fuel) in the exhaust plume.

 

The effect of mixture on power output is more pronounced in some planes.  IIRC mixture in the Yak doesn't have a large effect on power but in the Il-2 mod41 mixture has a dramatic effect.  In the Il-2 I can fine-tune my speed for formation flying using mixture alone.

 

I use full-rich mixture when using boost because, as Sheriff mentioned, full-rich mix has a nice engine cooling effect.

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