P-40 and Spitfire automatic mixture setting

[303_Bies]

Hi,

please correct me if i'm wrong:

1. in P-40 i need to set mix to 66% (auto rich) or 33% (auto lean) to let the device to regulate mix automatically. If i set i.e. 67% artomatic device is disconnecting.
2. In Spitfire i need to set full forward to set auto rich and full backward to set auto lean, but i.e. setting 99% is disconnecting automatic device.

cheers

 

 

[Swing]

Yes Bies, as far as i known, that's exactly that...

[Mad_Mikhael]

I don't know, but I'm pretty sure    that auto rich in P-40 got higher margin then 1%. Otherwise, it wouldn't make sense.

[303_Bies]

Thx for the answers, today i'll try to find out by myself how big this margin is and how easy is to accidentially disengage an automatic device. 

[OrLoK]

Id also like some clarification on this.

 

I try to keep it visually within the limits shown on the cockpit  quadrant as i play without tech tips.

[Guest deleted@83466]

Thanks for bringing this subject up, because I too have confusion about it.   I would also add in the subject of the Mig-3.  Mixture is said to be automatic at 50%, yet it doesn't actually appear to be optimal unless it is 84% (right under boost).  Meanwhile, in the Yaks, the plane specs say that mixture is completely manual, but I've actually read people say that it is "automatic up to 4000 meters" which I'm not so sure about (although it seems pretty happy at 100% mixture, all the way up to that altitude).

[Swing]

For the Mig3, mixture auto: Control lever set to 50%.

                                 Boost: Control lever set to 100%.

[OrLoK]

For the Mig3, mixture auto: Control lever set to 50%.

                                 Boost: Control lever set to 100%.

but does it *have* to be 50pc or *around* 50pc?

 

If it has to be exact, how does one tell?

[Swing]

it's 50% precisely...if your lever is set to 51%, you will have 51%...

[Guest deleted@83466]

For the Mig3, mixture auto: Control lever set to 50%.

                                 Boost: Control lever set to 100%.

 

Yes, we know that's what it says, but is anybody actually getting optimal, non-boosted power at 50%?

 

it's 50% precisely...if your lever is set to 51%, you will have 51%...

 

How do you know this?

If so, that might be kind of a problem then, and that's what the OP is asking.  There should be a range that accomodates even some amount of jitter in the controller...i.e. if you have one of the older Saitek quadrants, you might not be able to get it to precisely 50% on the nose.  In the case of the P-40 or others, I think the assumption has been that you simply have to be within a certain range to get auto-rich, not some precise percentage value.   This might be a good place for one of the actual developers to come in and clarify.

[Valis]

Did the original P-40 have notches on the gate for the pilot to know he had set the lever to the correct position? I would be very surprised if he was expected to find 33% and 66% just by looking. Were there any other audible or tactile cues available to let the pilot know he had found the correct lever position?

[sniperton]

I guess it's not like you regulate the mixture manually, where at certain positions some automatism suddenly kicks in. You regulate the mixture automatically all the time, from the leanest setting to the richest setting. One lever region is marked as Auto Lean-ish, another as Auto Rich-ish, another as Full Rich-ish, and you're not required to set the mixture to exactly 33% or 66% to have this or that.

I guess it's something like the prop pitch control. If you read in the manual that for landings the pitch has to be set to 11:30, it's important not to set it to 12:30 or 10:30, but you'll be fine with any value close enough to 11:30 (say, 11:20 or 11:40). Personally I don't find any sensible difference when setting the mixture to 65% or 67% instead of 66%.

[ZachariasX]

On 26.2.2018 at 8:43 AM, bies said:

If i set i.e. 67% artomatic device is disconnecting.

This would ne nonsense as an implementation and by no means could happen on the real plane. What you much rather have in the P-40 is a lever travel that is split up in 4 parts, for instance something like:

 0-25% -> Idle cut off

26-50% ->Auto Lean

51-75% -> Auto Rich

75-100% -> Full Rich.

 

As for the Spitfire:

0-50% -> Auto Rich (it is the "back" position)

51-100% -> Auto Lean

 

But actually, the only reasonable solution should be that in these respective ranges, the lever should "click" to the specific postion and only move to the next once you wound your axis sufficiantly far. A2A Simulations implement that in a nice way. There, also the Spitfire cooler lever moves in those discrete steps, even if it is mapped on an axis.

 

Suffice to say, there is room for improvement on how we can assign controls on plane functions in this game.

 

[ZachariasX]

On 26.2.2018 at 7:32 PM, OrLoK said:

but does it *have* to be 50pc or *around* 50pc?

 

If it has to be exact, how does one tell?

Although such arrangements might sound nonsensical to the ComfyArmChairPilot™, you do have such if you want a safe way to operate very different flight regimes on a single lever. You can map very different functions on a simple lever.

First ansewering the above  question: The Mig-3 does have ONLY 3 POSITIONS to select "on the lever". This means a whole range (maybe a 1/3rd of the travel each) is reserved for a certain engine regime. First third is IDLE-CUTOFF, second third is CONTINUOUS (an auto rich mixture I suppose), and FULL RICH. (Maybe someone can translate what is ritten there.)

It is of note that by all means, the Mig-3 mixture control is not as fancy as the Mustangs, where the "RUN" setting covers also the "boosted" mode. Yu don't use the EMERGENCY FULL-RICH there, unless there's something seriously wrong with the engine or you really asking for it by keeping the throttle firewalled.

 

There are however good reasons to put different types of control on one mixture lever. In case of the Boeing Stratocruiser, You have the lever that is full rich at 100%, then behind that there is "Auto-RICH", further back "Auto-LEAN" and behin that one starts a finely ticked region where you can further lean the engine below what auto lean will give you. It allows you to match the perfect mixture setting for optimal burn 8that you can determine with pen and paper and your flight engineer having a good eye on the dials and provided you are in a power regime that supports that. This way, you can milk some tiny bit more mileage from your ride.

 

Still, the mixture lever on Spit and Mig-3 et.al. should not be stating on technochat "how many %" you set it, but it should state your selected engine mixture mode. Our current implementation is obviously well, meant, but it is both impractical and misleading.

Maybe in further updates down the road that will be corrected as well.

[=362nd_FS=RoflSeal]

In the case of the MiG, mixture is auto rich from 0-74%, it tries to stay at 1040mmHg, if you increase mixture, MP rises then it falls back, and vice versa. Below 5% MP guage wobbles as engine starts coughing.

Above 74%, MP starts increasing, with 84% corresponding to 1120mmHg, above that you enter boosted power setting

[unlikely_spider]

25 minutes ago, RoflSeal said:

In the case of the MiG, mixture is auto rich from 0-74%, it tries to stay at 1040mmHg, if you increase mixture, MP rises then it falls back, and vice versa. Below 5% MP guage wobbles as engine starts coughing.

Above 74%, MP starts increasing, with 84% corresponding to 1120mmHg, above that you enter boosted power setting

Can I understand - if I change the mixture from say 20% to 60%, there is no difference actually made?

[=362nd_FS=RoflSeal]

MP will increases, but then go back to 1040mm