Mixture control update. Important!!

[ATAG_Torian]

Joined the server at the start of the early morning (dark) mission and jumped in a MkIa 100oct.
Low and behold the mixture is actually the right way round. Ie yellow flame when all the way back
and blue flame when pushed forward :doh:

Didn't pick this up b4 cause I couldn't easily tell the colour of the exhaust until the early morning
sorties.
Leaving it all the way back I didn't have to touch it at all from 0 to 19000 ft.
I could get the MkIa 100oct flying between 2400 to 2600 rpm with only 35% radiator open.

Leave the boost alone until u really need it. U can get some very good speed out of it
by tweaking prop pitch, throttle and rad and not fry ur engine. I think we are getting a tad
infatuated with flipping the boost switch and wanting to push it too hard.
For my part I need to experiment with that to see how far it can safely be pushed but a few
short (like 20 second) bursts seemed to be ok so far.

Now, which Brit fighters have the mixture modelled correctly?? Some1 might like to make a qwik
early morning map and go thru them all and report back.
I'm somewhat attached to the MkIa 100oct now but look forward to testing out the others in
light of this.

[Dutch]

But blue flame is what you want, and you had this with mixture all the way forward, but kept it set back for the climb, and......oh god, mixture is going to seriously mess with my head until they sort it out.

It doesn't help at all that they have it set up so's you need the lean setting for emergency boost, which is wrong, it works in the wrong direction to life which is wrong, but you need weak mixture above 12,000ft which is wrong and oh my god, I'll go and read IvanK's post again............:bsign:

[ATAG_Torian]

Dutchy Dutchy, I want u to double ur lithium dose for a week....calm...be at peace.
In the MkIa 100oct just leave the mixture set where it is...could b auto rich or just plain full rich I'm not sure but it's all u need
whether u want overboost or not. Being rich means it helps keep the engine cooler too.
Blue flame is good for economy. When I thought the mixture was the other way round I seemed to b able to fly forever on my
usual 50% fuel loadout but had a lot more difficulty keeping the engine cool not realising I was actually running lean all the time.
As I said, I don't know which way the mixture is set in any other Brit fighter. I'll try to get to them all if some1 else doesn't do it 1st.

Rest assured we shall solve the mystery of the sith and balance will b restored to the (red) force(s).

[Dutch]

Rest assured we shall solve the mystery of the sith and balance will b restored to the (red) force(s).

Calming excessively........you are. Erm. Well, anyway.... :)

[ATAG_Torian]

OK, Testing done, my findings are:

DH Hurricane.....mixture is back to front, full rich is all the way forward, lean is all the way back....might be why the DH is a pain to start, get lever all the way forward when u push throttle forward.
Hurricane Rotol...modelled correctly
Hurricane 100oct...modelled correctly

Spitfire MkI....back to front...as per DH Hurricane
Spitfire MkIa...modelled correctly
Spitfire MkIIa...modelled correctly
Spitfire MIa_100oct...modelled correctly

Blenhiem MkIV...couldn't see any change. It flew just fine with the mixture where it should be, all the way back. In-game the mixture throttles are all the way forward at spawn.

Made a semi-dark early morning map and these findings are based on yellow and blue flames from the exhaust. If these are modelled incorrectly then all bets are off.
Not sure if it's absolutely needed but I found running the mixture throttle all the way up and down seemed to have a settling in effect after u takeoff (take that for what it worth, maybe nothing).
Now if this is all correct then it should help us with correct engine management and fewer burnt engines. There are other factors of course like rate of climb (keep at 180mph or above), radiator settings
(I aim for between 35 to 50% depending on what I'm doing aiming to keep engine temp under 110* water temp), prop pitch (the higher u go the coarser u will need to run it...been using 2400 when up at 16 to 19000ft) and throttle adjustment...u don't necessarily need hammer down all the time, proper engine management will require adjusting throttle to where it's needed.
Joining the Allied side means u are gonna need to learn how to fly. If u don't want to learn how to fly then get in a 109 E4 and just enjoy urself :PP

[JG52_Krupi]

I just found out who is working on the COD RAF fm...


http://m.youtube.com/#/watch?v=25N-4zrk390

[Dutch]

Ted and Dougal would probably do as good a job, for sure.

No actually that's not fair. It was probably Jack. :D

[JG52_Krupi]

Ted and Dougal would probably do as good a job, for sure.

No actually that's not fair. It was probably Jack. :D


http://www.youtube.com/watch?feature=fvwp&v=MSHaCzb3yYk&NR=1

[Ivank]

DH Hurricane.....mixture is back to front, full rich is all the way forward, lean is all the way back....might be why the DH is a pain to start, get lever all the way forward when u push throttle forward.

Hurricane Rotol...modelled correctly
Hurricane 100oct...modelled correctly

Spitfire MkI....back to front...as per DH Hurricane
Spitfire MkIa...modelled correctly
Spitfire MkIIa...modelled correctly
Spitfire MIa_100oct...modelled correctly



Away from home so cant test at the moment. However I stand by my original post... that is in summary I think all the RAF fighters are cocked up mixture wise. the interlinking of Throttle and mixture controls further complicates the issue. Though this linkage is historically correct and would work just fine if the actual mixture logic was correct !

I am not so sure on the exhaust colour being a valid indicator of Mixture strength in CLOD. I know they (the devs) got all excited about it in the development days but chances are they cocked this up as well. The source for this was a graphic in the "Graphic war" book published a number of years ago. This featured an RAF poster used to teach engine fitters about Mixture affects and indications etc It wasn't intended for pilot use anyway. This then became a "feature" of COD. I don't think you will find to many references to fighter pilots referring to exhaust flame colour as a mixture guide ... pretty hard when the actual control you have is limited to AUTO RICH or AUTO LEAN. IMO I wouldn't be using it to determine what the COD game engine is doing. The only really valid method is I think to relate Mixture lever position to what you are getting out of the engine performance wise.

The absolute bottom line on all this is that all an RAF fighter pilot ever had to do was leave the the Mixture lever all the way BACK and just fly. This gives him AUTO RICH, no boost restrictions , automatic altitude compensation, no work load.... just go fly.

If you think the Spit IIA is correct think about this. With Boost Cut out running +12Lbs you IRL must be in AUTO RICH i.e. Lever All the way back. in CLOD to get smooth engine operation with Boost Cut out on you need the mixture lever fully forward (thats Auto Lean IRL ) ! ... i.e. its cocked up.

I will re visit this when I get home Sunday.

[ATAG_Bliss]

Some great info in this thread fellas! Thanks everyone for sharing.

[Vulgar]

I have noticed with the MkIa 100oct, that by watching the rpm's you will see the rpm's go up or down a bit with small mixture adjustments, then settle to your prop setting, the sweet spot is about 1/3 from lean. You can also watch the difference in color, just at or a bit after blue seems to give highest rpms for a given throttle setting. It does not seem to act like a lean auto or rich auto, but more like an incremental mixture control.

If you get the mixture in it's sweet spot, you will get good speed and or climb with lower boost, being able to keep your engine nice and cool and ready for a prolonged full boost fight.

[ATAG_Torian]

[I]If you think the Spit IIA is correct think about this. With Boost Cut out running +12Lbs you IRL must be in AUTO RICH i.e. Lever All the way back. in CLOD to get smooth engine operation with Boost Cut out on you need the mixture lever fully forward (thats Auto Lean IRL ) ! ... i.e. its cocked up.

Just tested this and u actually don't need the mixture throttle fully forward, just forward enuff to stop the splutter.
Tests running in both leaner and fully rich using the mixture as I have outlined previously definitely results in better economy running lean so my conclusion is that the mixture is actually modelled as I have outlined. Now whether the devs have porked boost cutout to run a little lean....who knows.

@ Vulgar....I agree. And not just mixture as u correctly point out. Throttle and prop settings as well as getting the radiator closed to somewhere between 35 to 50% and find the sweet spot on your favourite ride. I firmly believe we can squeeze more out of these ponies and hopefully come up with some conclusions about which is the better plane with the FMs we've been lumbered with. On the plus side it's been a good exercise in having to learn how to fly more like a real pilot would have had to fly.You are kinda forced to manage all the parameters and not just hammer down all the time and cook ur engine.

[Dutch]

Anything that helps fly the current RAF models better has to be a good thing, so thanks for your efforts Torian mate. :thumbsup:

I have to say that after optimising things with power/radiator/rpm in the Spits in this latest patch, I couldn't be bothered extending this to current mixture stuff. I just set it to where the engine is smooth and then adjust slighty for highest rpm at a given pitch setting, as I normally fly the CSP props.

But that's the point I was trying to make, the mixture controls shouldn't have variable manual settings. They should have two positions and that's it. No need to find a 'sweet spot'.

The one thing I'd differ with in your findings at first glance is with the Blenheim. There is a distinct increase in rpm on take-off with the mixture levers in the forward position, which again, should be auto-lean, but evidently is giving auto-rich. I seem to recall from memory that over a certain altitude, this needs to be altered to the lever back position (but i could have it wrong here), which IRL was auto-rich, but in the game is auto lean. So again, they're reversed, but also wrongly modelled, as auto-lean should be for economical cruise only, not for altitude, and either setting should automatically compensate for altitude, as per IvanK.

The whole thing does my 'ead in. :D

[ATAG_Torian]

I didn't do an extensive flight test on the Blenhiem. I just wanted to see the colour of the flame but couldn't see a difference with throttles set forward or back. Maybe they modelled it correct with the auto part.
Your point is well made tho regarding the set n forget aspect.

[Dutch]

Maybe they modelled it correct with the auto part.

Nope............No..........No, they didn't.............!

There is nothing truly auto about anything they've modelled mixture-wise in the RAF planes.

Mixture should be auto, in either position, but it isn't. The whole mixture thing is screwed, and as you've highlighted, different depending on the aircraft.

The foibles of mixture control are far more akin to what a Russian pilot would experience in a Yak-1, or MiG-3.

But, if you can find a way to get better performance out of the current RAF FMs, I seriously am all ears. :thumbsup:

Edit: Just found this link, by searching for 'spitfire mixture control'.

Couldn't think where else to put it, but it's a good link. :)

http://books.google.co.uk/books?id=Q9hy8-2LEqwC&pg=PA52&lpg=PA52&dq=spitfire+mixture+control&source=bl&ots=USiJfY2Ez8&sig=-1_uXpMLlGuXuTm3uzjwstrdtnM&hl=en#v=onepage&q=spitfire%20mixture%20control&f=false

[ATAG_Torian]

But, if you can find a way to get better performance out of the current RAF FMs, I seriously am all ears.

Workin on it. It seems to me that some planes perform better down low than up high and some are better up high than down low. But that's just my impression so far based on my engine management which may or may not be optimal.

[Ivank]

Torian when you say "definitely results in better economy running lean " ... how are measuring that ? The only real method IMO is somehow extracting actual Fuel Flow for specific Flight and power conditions with varying mixture lever positions.

[ATAG_Torian]

Based on same fuel loadout, same climb to altitude and similar flight pattern. Running lean as in the way I have the throttle orientation worked out gets u longer flying time.
It's not a comprehensive, double blind, placebo controlled study but it's what I am finding. Others may want to confirm or refute it in their own testing but so far it's working for me.

[Dutch]

One thing's for sure, using +11 boost for any length of time eats fuel like a Soab.

When taking off in the 100oct, take 100% fuel. if you use +11 boost, you'll need all of it! :D

[Ivank]

General Fuel consumption over a sortie is not imo a suitable means to determine whats really going on. Fuel Flow is really the only method to determine it for sure. Straight out Level runs say for 5 mins, with constant Boost/RPM settings. If Fuel Flow cant be extracted from the FM the alternative might be weight change over a fixed time. This would provide a Fuel Flow value in terms of change in aircraft weight.

Back home now so will do some more testing.

[Ivank]

Copy Paste of my post on RAF Mixture on 1C forum

Based on Torian's findings I went off and did some flight tests to determine Fuel Flow versus mixture.

I stand corrected based on Fuel flow tests CSU Spits and Hurris have correct Mixture lever orientation, however Levers are incremental and should be 2 position only. Boost Cutout requires some Leaning of the mixture to ensure smooth operation ... incorrect should be AUTO RICH.

Method:
10 min level Flight stabilised at 10,000ft on QNH 1013 +- 50 feet throughout.
Power Fixed at +2/2400RPM
RAD Full open (to provide constant test setting)
Full CEM
Fuel Set to 20% in FMB
Note via Tool tip Fuel Remaining at start and at 10mins elapsed on Stop watch.

RESULTS

Spit IA
Mixture Lever Full Back
Fuel Used over 10 min 8 Gall
Fuel Flow 0.8Gall min

Mixture Lever as far Forward as possible ensuring Smooth engine operation (about 75% forward ... any further forward resulted in rough running)
Fuel used over 10min 6 Gall
Fuel Flow 0.6Gall min

Conclusion Moving Mixture lever forward is Leaning mixture.
Mixture lever not 2 Position but incremental (WRONG)
Boost Cut Out req mixture lever forward of 1/3 to Full forward (Wrong)

Spit 1A 100 Octane
Mixture Lever Full Back
Fuel used over 10 min 8 Gall
Fuel Flow 0.8 Gall min

Mixture Lever forward as far forward as possible to achieve smooth engine operation (about 75% forward ...any further forward resulted in rough running)
Fuel used over 10min 7 Gall
Fuel Flow 0.7 gall min

Conclusion Moving Mixture lever forward is Leaning mixture.
Mixture lever not 2 Position but incremental (WRONG)
Boost Cut Out req mixture lever forward of 3/4 to Full forward (WRONG)

Spit IIA
Mixture Lever Full Back
Fuel used over 10 min 9 Gall
Fuel Flow 0.9 Gall min

Mixture Lever forward as far forward as possible to achieve smooth engine operation (about 75% forward ...any further forward resulted in rough running)
Fuel used over 10min 7 Gall
Fuel Flow 0.7 gall min

Conclusion Moving Mixture lever forward is Leaning mixture.
Mixture lever not 2 Position but incremental (WRONG)
Boost Cut Out req mixture lever forward of 1/3 to 1/2 Full forward (WRONG)

Hurricane I ROTOL
Method Fuel Feed Main Tanks. Fuel used Total read from both Left and Right Tanks based on assumption that fuel feed simultaneously from both Left and Right tanks.
Mixture Lever Fully Back
Fuel used over 10 min 10 gall
Fuel Flow 1 gall min

Mixture Lever forward as far as possible to achieve smooth engine operation (about 75% forward .... any further forward resulted in rough running)
Fuel used over 10 min 6 Gall
Fuel Flow 0.6 gall min

Conclusion: Moving Mixture lever forward leans mixture
Mixture lever not 2 position but incremental (WRONG)
Boost Cut Out req Mixture lever Fully back (CORRECT)

Hurricane I ROTOL 100 Octane
Method Fuel Feed Main Tanks. Fuel used Total read from both Left and Right Tanks based on assumption that fuel feed simultaneously from both Left and Right tanks.
Mixture Lever Fully Back
Fuel used over 10 min 10 gall
Fuel Flow 1 gall min

Mixture Lever forward as far as possible to achieve smooth engine operation (about 75% forward .... any further forward resulted in rough running)
Fuel used over 10 min 9 Gall
Fuel Flow 0.9 gall min

Conclusion: Moving Mixture lever forward leans mixture but not as much as in 87 Octane ROTOL Hurricane.
Mixture lever not 2 position but incremental (WRONG)
Boost Cut Out req Mixture lever 3/4 Forward (WRONG)

FIXES REQUIRED
Mixture lever should be two position only not incremental
Full Back = AUTO RICH (automatic altitude compensation in rich schedule no Boost restrictions)
Full Forward= AUTO LEAN (automatic altitude compensation in weak schedule Boost restrictions apply)

2 PITCH TESTING IN COARSE
Slightly different method. Set +2lbs Boost Coarse pitch and accept RPM achieved, all other aspects the same as in CSU tests.

SPIT I DH COARSE
Mixture Lever Full Back achieved RPM 2000
Fuel used over 10 min 6 Gall
Fuel Flow 0.6 Gall min

Mixture Lever full forward achieved RPM 2150
Fuel used over 10min 8 Gall
Fuel Flow 0.8 gall min

Conclusion Moving Mixture lever forward is en riching mixture. (WRONG)
Mixture lever not 2 Position but incremental (WRONG)
Boost Cut Out req mixture Full forward (should be Full Aft if orientation is correct)
Richer Mixture results in increased RPM for a given Boost

Hurricane I DH
Mixture Lever Full Back achieved RPM 2000
Fuel used over 10 min 6 Gall
Fuel Flow 0.6 Gall min

Mixture Lever full forward achieved RPM 2100
Fuel used over 10min 8 Gall
Fuel Flow 0.8 gall min

Conclusion Moving Mixture lever forward is en riching mixture. (WRONG)
Mixture lever not 2 Position but incremental (WRONG)
Boost Cut Out req mixture Full forward (should be Full Aft if orientation is correct)
Richer Mixture results in increased RPM for a given Boost

2 PITCH FIXES REQUIRED
In both Spit and Hurri DH mixture lever orientation is WRONG and needs to be changed
Lever back should be AUTO RICH
Lever forward should be AUTO LEAN
Mixture lever is incremental should be 2 position only

NOTES
AUTO RICH provides automatic altitude compensation on rich schedule without Boost restrictions
AUTO LEAN provides automatic altitude compensation on a Lean schedule with Boost Limitations.

In AUTO LEAN engine Boost limitations should be
Hurricane I, Spitfire I +2.5lbs Boost
Spitfire II +4lbs Boost

EDIT: All RAF fighters tested.

[ATAG_Torian]

Much appreciated Ivank. Was pretty sure my bush pilot math was putting me in the right direction but thankfully u have put in the precision work to confirm my guestimates. At least the yellow/blue, rich/lean exhaust modelling is correct.
I can't tell any difference in colour in the exhaust flame of the Blenhiem but flights getting up above 5000ft needed the mixture throttles all the way forward. Methinks forward may well be rich which is back to front (at least it's only a 2 setting mixture and not a sliding throttle). Need to do some more testing in the Blenny tho.
At least we know where we stand mixture wise and can work around the flawed modelling. Will u be making MG/1C aware of these findings ?

[ATAG_Snapper]

Phenomenal work, IvanK. Thank you very much for this. Those of us flying the RAF fighters knew something was amiss with the different models' mixtures, and you have nailed it down. Thanks to you, too, Torian, for going a little deeper than the rest of us on the RAF mixture issue and contacting IvanK with your observations.

Speaking as an online virtual RAF COD pilot, obviously authenticity is the primary goal. Getting the mixture fixed will also fulfill the overall objective of RJ Mitchell with respect to mixture control from the pilot's POV: simplicity. At present in the Spitfire 1a 100 octane I feel busier than a one-armed paper hangar when in combat, and mixture manipulation is an unwanted, but currently necessary, workload which doesn't help maintaining Situation Awareness. Nor does a blown engine!

Thanks again to you both. Hopefully the devs will implement IvanK's recommendations.

[Ivank]

Everything will be passed directly to the Devs. Just got to do the 2 Pitch Hurri. I will do that tomorrow.

[Dutch]

Fantastic stuff. :thumbsup:

Thanks for all the work Torian and IvanK. I discovered myself that the 'orientation' in the Ia and Iaoct was ok, but that the 'lean' setting for BCO was wrong in the 100oct, but really couldn't be bothered testing the rest. Suffered 'Tester's burnout' I think. I seem to recall that even in the 100oct, that at height you need to 'lean out' the mixture a touch for optimum rpm though, which implies there is still a touch of variability about it, which also matches Ivan's results.

In the rest of 'em, I still just fiddle with it til it works (ahem).

:)

[ATAG_Colander]

Ivank,

I think I speak for all in ATAG when I say, Thanks for taking the time to do this :salute:.

[Ivank]

Doing the Blenheim and its problematical to say the least.

1. I cannot run smooth operation with Mixture levers back (normal) at any altitudes above 6000ft with +4/COARSE
2. Had to perform tests at 5000ft to be able to achieve smooth Engine operation in both NORMAL (BACK) and LEAN (FWD) positions.
3. Tests inconclusive.

METHOD
Stable Flight CHT 200C, BOOST +4, 5000Ft Coarse Pitch Rads 3 clicks open, CHT Stable at 200 C, QNH 1013

LEVER FORWARD in LEAN POSITION
Achieved RPM 1920, Achieved IAS 210
Fuel Used after 10 mins 12Gall (Total)
Fuel Flow 1.2gpm (Total)

Placed Mixture Lever to REAR (NORMAL) position RPM Reduced to 1820 RPM IAS reduced to 200.

LEVER IN REAR NORMAL POSITION
Achieved RPM 1820, Achieved IAS 200
Fuel Used after 10mins 12 Gall (Total)
Fuel used after 20mins 22 Gall (Total)
Fuel Flow 1.1gpm Total in 20min test .... too close to call.

CONCLUSION
Inconclusive with respect Fuel Flow. Same FF achieved in both mixture lever positions ! Though the 20min test might imply that with the lever back fuel flow is less ... though 1.2gpm v 1.1gpm is too close to call imo.
Given Stable engine operation above 6000ft cannot be achieved in Rear (Normal) position then AUTO function is not operating.
Given at 5000ft selecting Mixture to REAR (Normal) results in reduced RPM and IAS I think it implies that actual Mixture orientation is operating in reverse. Maybe supported by 20min Fuel flow tests as well. Might need to look at exhaust colour to add further data.

RECOMMENDED FIXES (work in progress)
Mixture control needs to be AUTO RICH or AUTO LEAN in that automatic altitude compensation is provide in both.
Stable operation at all altitudes in NORMAL (AUTO RICH) should be possible without boost restrictions
Stable operation at all altitudes in WEAK (AUTO LEAN) should be possible WITH boost limitations
Boost limits in WEAK (AUTO LEAN) +1.5lbs

[ATAG_Torian]

The problem above 5000ft in a Blenhiem is that u need to add carburettor heating to both engines or u will get engine problems.

[Ivank]

Ref Exhaust colours.

Mixture Lever back in NORMAL (AUTO RICH) I see Blue flame predominately.
Mixture Lever Forward WEAK (AUTO LEAN) I see yellowish Flame predominately.

The Mixture colour diagnostic chart from Graphic War:

http://i40.photobucket.com/albums/e215/zulu64/mixturecolour.jpg

Interesting that correct Mixture flame is short tight bluish whilst Rich is Long Blue flame.
AUTO mix should ideally provide the correct ratio at all times. Though how you differentiate this between AUTO LEAN and AUTO RICH in terms of exhaust colour airborne is a moot point. Its also worthy of note that the chart talks about tube length etc.

Regarding Carby heat. the Mercury engine did in real life require greater use of Warm air than most other engines. This was just an alternate source of Air flow from RAM air to air drawn from within the engine cowling area. The pilots notes state:

"The Air Intake controls should be in the WARM position (Down) for all operational conditions except the following:

(i) When starting the engine
(ii) When boost pressure exceeds +3.5Lbs
(iii) When atmospheric temperature exceeds 15C"

I have tried with the AIR INTAKE control WARM (DOWN) and RAM(UP). It makes no diff at 10,000feet any time I drag the mixture levers back to the rear (NORM) position I get rough running.

[turkish]

In trying to wrap my head around Mixture I did a quick test with all 4 spitfires. What i did was go into FMB, spawn each plane one by one at 10km and adjust mixture and these were my finding.

Spitfire I - 100% = Lean / 0% = Rich
Spitfire Ia - 100% = Rich / 0% = Lean
Spitfire IIa - 100% = Rich / 0% = Lean
Spitfire Ia Octane - 100%= Rich / 0% = Lean

Spit I - At 10km plane would shudder and shake when i push the mixture lever all the way back. (Pulling the lever full back was rich)
Spit Ia oct, Ia and IIa - At 10km plane would shudder and shake when I push the mixture lever all the way forward. Thoughts? (Pushing the lever full foward was rich)

Judging by this the Spit I is the correctly modeled craft.

[ATAG_Torian]

In trying to wrap my head around Mixture I did a quick test with all 4 spitfires. What i did was go into FMB, spawn each plane one by one at 10km and adjust mixture and these were my finding.

Spitfire I - 100% = Lean / 0% = Rich
Spitfire Ia - 100% = Rich / 0% = Lean
Spitfire IIa - 100% = Rich / 0% = Lean
Spitfire Ia Octane - 100%= Rich / 0% = Lean

Spit I - At 10km plane would shudder and shake when i push the mixture lever all the way back. (Pulling the lever full back was rich)
Spit Ia oct, Ia and IIa - At 10km plane would shudder and shake when I push the mixture lever all the way forward. Thoughts? (Pushing the lever full foward was rich)

Judging by this the Spit I is the correctly modeled craft.

Hi turkish,
The mixture settings have been made unnecessarily confusing but it's good to see u trying to work it all out.
Not sure if u have carefully read thru the previous posts or not and don't know if English is your native tongue or not but will endeavour to keep it simple.
In the Spit I the mixture is modelled wrongly in that u have to PUSH the lever all the way forward to get full rich which is what u need. If u PULL it all the way back u will get lean mixture.
It is the same in the DH Hurricane.
In all other British fighters the mixture is the right way.
The % value is oriented one way. 0% the lever is all the way back. 100% the lever is all the way forward. Better to look at where your lever is than go by a %.
Therefore your findings are incorrect. The reason your Spit I shudders and shakes when u PULL the lever all the way back is u are fully lean.
Your Ia_oct, Ia and IIa shudder when u PUSH the lever all the way forward is because once again u are fully lean.

The way it actually is at the moment is:
Spitfire I - 100% = Rich / 0% = Lean
Spitfire Ia - 100% = Lean / 0% = Rich
Spitfire IIa - 100% = Lean / 0% = Rich
Spitfire Ia Octane - 100%= Lean / 0% = Rich

As stated previously the Mk I Spit and DH Hurricane have the mixture the WRONG way around so they are INCORRECTLY modelled.
Hope this helps.

[turkish]

So then from what I now understand from that is you want lean mixture at low altitude and rich at high altitude? Which is basically the opposite I've been reading i.e. Rich at low (more air in the engine) Lean with altitude (Less air in the engine)

But if
Spitfire I - 100% = Rich / 0% = Lean
Spitfire Ia - 100% = Lean / 0% = Rich
Spitfire IIa - 100% = Lean / 0% = Rich
Spitfire Ia Octane - 100%= Lean / 0% = Rich

Then at 10km above sea level the Spit I should shake and shudder with the lever at 100% (Full Forward with the throttle), and his wasn't the case. (Using the digital readout HUD engine info)


The % value is oriented one way. 0% the lever is all the way back. 100% the lever is all the way forward. Better to look at where your lever is than go by a %.
Therefore your findings are incorrect. The reason your Spit I shudders and shakes when u PULL the lever all the way back is u are fully lean.
Your Ia_oct, Ia and IIa shudder when u PUSH the lever all the way forward is because once again u are fully lean.

I would think the reason the Spit I shakes at 10km is because when I pull the lever back (0%) I am putting the plane into Rich i.e. more fuel but at such a high alt it can't do it because of the less air so in which case I need to go lean by pushing the lever forward (100%) to stop the shaking.. which it does.

[ATAG_Snapper]

Hi Turkish,

The Spit and Hurri mixture controls in Cliffs of Dover are a mixed up mess, as you've found out.

In a nutshell, to get them modelled EXACTLY as they were in Real Life, the following needs to be done:

1) Mixture Auto Rich with lever fully pulled back. This is the setting you and I will leave it in basically 100% of the time, regardless of altitude.

2) Mixture Auto Lean with lever fully pushed forward towards the cockpit. This setting will virtually never be used by us. This is strictly for high altitude, economical cruising at moderate engine settings. Useful in Real Life for long patrols or escort, to minimize fuel consumption. A full tank of gas in Cliffs of Dover in Auto Rich gives us at least 1.5 hours of flight -- so running out of gas isn't a concern for us in the sim.

In the Real Life Spitfires and Hurricanes there was no middle settings or adjustments between Rich or Lean. Although in CoD you can adjust the mixture, this is not authentic. It's either Auto Rich or Auto Lean. Auto Rich handles all our flying needs in this sim.

Thanks to IvanK for earlier giving us the straight dope on this! :thumbsup:

Hope to see you in the skies, Turkish!

[turkish]

Hi Turkish,

The Spit and Hurri mixture controls in Cliffs of Dover are a mixed up mess, as you've found out.

In a nutshell, to get them modelled EXACTLY as they were in Real Life, the following needs to be done:

1) Mixture Auto Rich with lever fully pulled back. This is the setting you and I will leave it in basically 100% of the time, regardless of altitude.

2) Mixture Auto Lean with lever fully pushed forward towards the cockpit. This setting will virtually never be used by us. This is strictly for high altitude, economical cruising at moderate engine settings. Useful in Real Life for long patrols or escort, to minimize fuel consumption. A full tank of gas in Cliffs of Dover in Auto Rich gives us at least 1.5 hours of flight -- so running out of gas isn't a concern for us in the sim.

In the Real Life Spitfires and Hurricanes there was no middle settings or adjustments between Rich or Lean. Although in CoD you can adjust the mixture, this is not authentic. It's either Auto Rich or Auto Lean. Auto Rich handles all our flying needs in this sim.

Thanks to IvanK for earlier giving us the straight dope on this! :thumbsup:


Hope to see you in the skies, Turkish!

Hello, I appreciate the reply and understand, but what I'm trying to figure out is how to fly this plane in the interrim until it's fixed.

ive read through everything and still dont understand, especially when I run the plane at 3 lbs and it shakes and ill move the mixture and it stops shaking, but then i go to 6 lbs and it shakes again, move the mixture again and it stops, makes no sense

[ATAG_Snapper]

I fly all the Spits and, as they are now, as Torian has listed, some are different from others which is both confusing and ridiculous. All to say, I feel your pain.

Basically, I fly each Spitfire in Full Rich. As we've established, for most of the Spits that means pulling the lever right back and leaving it there. The Spitfire MK 1 (2-speed prop) and the Hurricane DH5-20 (2-speed prop) are the exceptions: Full Rich is fully forward (towards the cockpit).

You can leave it in Full Rich and the plane will be fine. Some of us do adjust the mixture a little bit more lean as we gain altitude, but it's important to remember going back to Full Rich as you lose altitude later. Some use the exhaust flame colour as a guide, gradually leaning the mixture until the flame just starts to turn blue.

The 100-octane Spitfire 1a, 100-octane Hurricane MK 1, and the Spitfire MK 2a have the ability to apply extra boost to the engine if you activate the "Boost Cut Out Overide" (Bloody Brits always have to make things complicated -- just like their silly hyphenated last names. They just couldn't call it "WEP" and be happy with that! err, you're not British, are you Turkish?). When you do "pull the tit" (Hurricane 100 octane) or "push through the gate" (Spit 1a 100 octane & Spit 2a) the devs thought to throw their own spanner in the works and force us to push the mixture to Full Lean (and pull back to Full Rich when throttling back) -- or else your plane starts shaking. Just for kicks, if you go to Boost Cut Out Override at 3000 rpms, your engine sees fit to blow a gasket after about 30 seconds or so anyway.

Peso, if you combine Torian's advice with IvanK's and my own, plus we'll throw Dutch's 2-pence into the mixture (ha! Pun!) ....... you should have no difficulty at all! :D

[turkish]

I fly all the Spits and, as they are now, as Torian has listed, some are different from others which is both confusing and ridiculous. All to say, I feel your pain.

Basically, I fly each Spitfire in Full Rich. As we've established, for most of the Spits that means pulling the lever right back and leaving it there. The Spitfire MK 1 (2-speed prop) and the Hurricane DH5-20 (2-speed prop) are the exceptions: Full Rich is fully forward (towards the cockpit).

You can leave it in Full Rich and the plane will be fine. Some of us do adjust the mixture a little bit more lean as we gain altitude, but it's important to remember going back to Full Rich as you lose altitude later. Some use the exhaust flame colour as a guide, gradually leaning the mixture until the flame just starts to turn blue.

The 100-octane Spitfire 1a, 100-octane Hurricane MK 1, and the Spitfire MK 2a have the ability to apply extra boost to the engine if you activate the "Boost Cut Out Overide" (Bloody Brits always have to make things complicated -- just like their silly hyphenated last names. They just couldn't call it "WEP" and be happy with that! err, you're not British, are you Turkish?). When you do "pull the tit" (Hurricane 100 octane) or "push through the gate" (Spit 1a 100 octane & Spit 2a) the devs thought to throw their own spanner in the works and force us to push the mixture to Full Lean (and pull back to Full Rich when throttling back) -- or else your plane starts shaking. Just for kicks, if you go to Boost Cut Out Override at 3000 rpms, your engine sees fit to blow a gasket after about 30 seconds or so anyway.

Peso, if you combine Torian's advice with IvanK's and my own, plus we'll throw Dutch's 2-pence into the mixture (ha! Pun!) ....... you should have no difficulty at all! :D

AND THERE LIES THE PROBLEM!

So in order to fly the 100 oct you need to lean the mixture with boost.. aha!

Ah yes this is apparent when you spawn a spit 1 the mixture starts full forward at 100%

Flew a Spit IIa, had the lever full back.. IE the panel on the spit where the mix is says decrease.. climbed up to a HE 111 that was about 2-3k above me, used WEP until my engine heated up, turned wep off, caught the 111 shot him down, never touched mixture :)

O and while I have you hear, whys my spit compass telling me 90 degrees is south ? :)

[ATAG_Snapper]

First, congrats on shooting down the He111! :thumbsup:

Yeah, it's just goofy how you have to go Full Lean when you go all out to 11 lbs boost. That's just plain wrong! In a Real Spit or Hurricane you'd quickly/instantly detonate your Merlin engine doing that. The Real Life mixture system was designed to be very simple for a low-hours young pilot to use under combat stress. Hopefully the devs will see fit to fix it.

I've been using the Spit/Hurri compass regularly to keep in practice. In this sim it's a little awkward to use, even when you get used to it -- especially when resetting the gyrocompass in flight. There are some fairly good how-to videos on YouTube which I'll try to find for you.

[ATAG_Torian]

I posted this link earlier but will post it again along with a paragraph that may explain why so many are burning out engines. Mixture orientation is critical to get right.

http://flighttraining.aopa.org/students/solo/special/mixture.html

"Excessive leaning at cruise power above 75-percent power will invite engine damage from overheated valves and incur the possibility of detonation. The probability of damage from over-leaning decreases rapidly as cruise power is reduced from 75 percent. For example, there is considerably less, if even any, possibility of engine damage from over-lean mixtures at 50-percent power. However, an over-lean mixture can foul spark plugs and combustion chambers because of cylinder misfiring.

Many older engines are equipped with non-alloy steel exhaust valves. During normal cruise power (approximately 50 percent to 75 percent) the exhaust valve will become glowing hot during the period that it is open and exposed to the hot gases leaving the cylinder. If the mixture is lean enough to create an oxidizing atmosphere, the exhaust valves usually will be damaged. (An oxidizing atmosphere is always present in lean mixtures.)"

Leaning the mixture is fine but leaving it too lean and then entering a dogfight using full throttle = barbecueing ur valves.
Pilots new to CloD who are not familiar with the Mixture orientations as they are modelled at present will likely have problems.

[turkish]

I'm on the server right now, testing Spitfire MK Ia 100 Octance and I managed to get to 22,000 Feet (Had to lower my throttle and RPMs a few times to prevent overheating) and I'm testing my mixtures. Now what we know is Full back is AUTO RICH and full forward is AUTO LEAN, and Lean is for economy. At this very moment i'm crusing at 22k Feet with about 50 percent throttle and low RPMs trying to use economy by going AUTO LEAN with the mixture full foward (100%) but once I get it full forward my planes shakes and loses power, this makes no sense. Once I start shaking with 50% throttle low rps and leaned mixture if I boost to 100% throttle and 100% RPMs the shaking stops and I get power back. It's contrary to what we believe that Back is rich and forward is lean.

Can anyone explain why when I try to cruise at a high alt.. now 24k Feet since starting this.. with lean mixture my plane loses power? and why when i then go 100% with throttle and rpms with 100% mixture it gets power back?

On to test the Spit Ia now :)

EDIT: Once I hit 25k Feet i leveled out and began a cruise with Throttle at about 50, low RPMS (Above 2000 RPMs) and started with 0% mixture (FULL RICH) to test the economy again with 100% Lean Mixture that plane lost power as it did at the previous 22k Feet but what changed is that when i went 100% max Throttle and 100% max RPMs it STILL continued to shake and lose power, contrary to what it was doing at 22k Feet (Gained power back)

also between the Spit I, Ia Octane and Spit IIa, it seems like the Spit Ia Octane and Spit IIa (which had 100 Octane IRL) overheat alot faster then the Spit I, i'm on to testing the Ia now to see if it stays as cool as the spit I, i believe they have the same octane fuel.

EDIT: I'm sure I'm not telling you guys anything new, this is more so for myself.

"With 100 octane fuel the supercharger of the Merlin III engine could be "boosted" to +12 lbs/sq.in., producing 1,310 hp (977 kW) at 3,000 rpm at 9,000 feet (2,743 m) with a time limit of five minutes.[35] This increased power substantially improved the rate of climb, especially at low to medium altitudes, and increased the top speed by 25-34 mph up to 10,000 feet.[22][N 2] During the Battle of France and over Dunkirk RAF Hurricanes and Spitfires were able to use the emergency boost.[36][37]"

So basically the Spit IIa and Spit Ia octane have boost (Spit I and Ia don't) This boost is possible with 100 octane fuel (Which means Spit IIa in COD does have 100 octane). Boost was used for rapid climbing but only for about 5 minutes.

So basically the FM for the spitfires are not completely accurate. As you've all said.

[71st_AH_Code_E]

I'm by no means an expert, but I don't think that Auto Rich and Auto Lean are simulated in CoD.

As IvanK and others brought out earlier, the spitfires should be that way, but they aren't. Instead they have incremental mixture controls, which means that your sweet spot at altitude will be somewhere in the middle. By pushing the mixture control full forward, you completely leaned the engine, which is damaging and can cause overheating. Torian described it well with this quote,
"Excessive leaning at cruise power above 75-percent power will invite engine damage from overheated valves and incur the possibility of detonation. The probability of damage from over-leaning decreases rapidly as cruise power is reduced from 75 percent. For example, there is considerably less, if even any, possibility of engine damage from over-lean mixtures at 50-percent power. However, an over-lean mixture can foul spark plugs and combustion chambers because of cylinder misfiring. So when you had the throttle back at 50% with full lean, it ran ok. But at full throttle bad things start to happen. Because the Spits in this game DO NOT have Auto Lean or Rich, you have to find the right spot yourself. Full lean with full throttle is going to be bad, especially the more altitude you get. You're basically starving the engine and it has fewer ways to get rid of heat. Also starving the engine of fuel is reducing your power.

Now at 25,000 feet, you won't be able to run full rich and have your best performance. But because of the current status of the mixture controls in this game, you'll have to lean the engine SOME and experiment to find the sweet spot. IvanK's post on flame color can be helpful for this. As Torian brought out, you definitely don't wont to push the mixture control full lean and have full throttle at the same time.

In the real world, the pilot would have set the plane to Auto Rich, or Auto Lean, and left it there. But we just don't have that convenience. You have to guess where a good spot is and hope you don't blow up!

[ATAG_Snapper]

Bingo, Code_E! :thumbsup:

[Dutch]

I've been using the Spit/Hurri compass regularly to keep in practice. In this sim it's a little awkward to use, even when you get used to it -- especially when resetting the gyrocompass in flight. There are some fairly good how-to videos on YouTube which I'll try to find for you.

Sometimes I just don't know why I bother, I really don't. Sheesh. This is on the ATAG forum somewhere in 'planes x 3' but it's quicker for me to find it direct from my channel.


http://www.youtube.com/watch?v=oyr9Ge8qN6Y&list=UUo9f9X9-8JQXXqL2ObozOSQ&index=16&feature=plcp

[ATAG_Snapper]

See? I KNEW there was a good video out there! :)

[turkish]

So when you had the throttle back at 50% with full lean, it ran ok. But at full throttle bad things start to happen. Because the Spits in this game DO NOT have Auto Lean or Rich, you have to find the right spot yourself. Full lean with full throttle is going to be bad, especially the more altitude you get. You're basically starving the engine and it has fewer ways to get rid of heat. Also starving the engine of fuel is reducing your power.

The opposite. at 22k feet when i had the throttle at 50% and full lean it DID NOT run okay, it lost power.. by going 100% throttle with Full Lean it ran okay.. at 22k feet.

[ATAG_Snapper]

Hmmm, more Cliffs of Dover mixture goofiness. Turkish, I'm following -- and noting -- your firsthand observations carefully, especially at the relatively high altitudes you're trying them. It's valuable input for this current beta 1.08.

Personally, I wouldn't try making too much rhyme or reason out of the "why is this?" -- the mixture settings are all wrong compared to the Real Life Spitfires and Hurricanes. Worse yet, they're inconsistent even within the sim. We'll all go nuts GUARANTEED trying to find explanations for the unexplainable.

Hopefully the upcoming Release Candidate beta patch will render the current mixture mishmash moot, mate. (say THAT 100 times quickly!).

[Dutch]

mixture mishmash moot, mate.

:)

Nice!

[turkish]

Mixture update:

There is a bind in the aircraft controls for just Rich and Lean.. I bound these and when I pressed the Rich bind it brought mixture to 100% and lean brought it to 0%. Tested with Spitfire IIa