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View Full Version : the 120% mixture setting - why ?



JG53Frankyboy
08-25-2005, 08:20 AM
some planes can set their mixture to 120% (useful only for low altitude around 750m) - F4U , F6F , Ki84 , A6M5 for examples - but why ?

i see no better performance , no more engine revs, no MAP .

has anyone a usefull reason to use it ?

neural_dream
08-25-2005, 08:21 AM
supposedly for take-off and landing, but i've never bothered.

JG53Frankyboy
08-25-2005, 08:23 AM
well, i'm seeing no difference in performance! ?
perhaps bad test. there for my question here.

Dtools4fools
08-25-2005, 09:21 AM
I thought it sometimes can help continue flying with a damaged engine?
****

han freak solo
08-25-2005, 09:49 AM
My memory may be wacked, but I thought excessive fuel mixture provides a poor but reasonable cooling benefit for an engine. Fouls plugs, too.

I guess that could help bring home a damaged engine???????

fordfan25
08-25-2005, 09:57 AM
with gas prices the way thay are there should be sttings for -120% lol

p1ngu666
08-25-2005, 09:58 AM
think it gives abit more power, maybe u should try acceloration test franky?

neural_dream
08-25-2005, 09:58 AM
with gas prices the way thay are there should be sttings for -120% lol
http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

JG53Frankyboy
08-25-2005, 10:02 AM
Originally posted by p1ngu666:
think it gives abit more power, maybe u should try acceloration test franky?

as i said, i see no difference in
speed
engine rpm
MaP
when flying one of these planes at full power and switching between 100% and 120% mixture flying low........

cooling effect, perhaps, didnt test if the time till "engine overheat" has changed ore if you can fly longer in "overheat" condition till engine damage - but i doubt it, just a guess http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

JG53Frankyboy
08-25-2005, 10:04 AM
Originally posted by fordfan25:
with gas prices the way thay are there should be sttings for -120% lol
gimme your US prices http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

i paid 1,36 " today the LITRE (!) , and i have a 75litre tank in my mercedes http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

3.JG51_BigBear
08-25-2005, 10:05 AM
Squad mate of mine did tests when PF was first released and noticed an increase in speed on the deck.

JG53Frankyboy
08-25-2005, 10:09 AM
so much changed since 3.0 http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

Hologram3
08-25-2005, 10:20 AM
Originally posted by fordfan25:
with gas prices the way thay are there should be sttings for -120% lol

No problem in the U.S. They'll just raise taxes again, the civilians will pay for it anyway. http://forums.ubi.com/groupee_common/emoticons/icon_mad.gif

We're used to it.

SeaFireLIV
08-25-2005, 10:37 AM
Just my 2 pennies, but when I`m flying something like the LA5 (as I was today), I found myself chasing low, I mean hugging the earth, mere feet away, after a fleeing 109. I always hit my 120mix and certainly felt an improvement, ie I slowly gained some on the 109 and forced him into a breaking manouever.

Now I didn`t measure this with a fine tooth combe, or ultra measure it in an anal fashion, but to me it always gives a little extra performance at low height. You must remember to kick off 120mix once you climb though!

neural_dream
08-25-2005, 11:59 AM
What happens if you don't go back to 100%? and approx. over what altitude?

JunkoIfurita
08-25-2005, 04:25 PM
Usually over approximately 300m (i.e. anything else but ground hugging).

What happens is your engine becomes starved because the over-rich fuel can't be burnt (that's why you get the thin black lines of smoke coming from your engine). Your revs drop off, and you start losing speed (do it long enough and your engine will gum up for good). It's similar to when you go over 3500m in the I-16 (for a quick example). You need to reduce the fuel mixture to 80% to avoid starving the engine.

Although if you're spending a lot of time above 3500m in an I-16 you're asking for it anyway http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

----

SeaFireLIV
08-25-2005, 05:21 PM
Originally posted by neural_dream:
What happens if you don't go back to 100%? and approx. over what altitude?

For me, personally, if you go high at 120% the engine just starts acting funny, making funny sounds which always reminds me to kick back to 100% or 80%. I believe if you do nothing and keep the engine at high power you`ll damage it for good. I`m not sure of the height, but it`s pretty low, JunkoIfurita is probably right with the number.

Hiriyu
08-25-2005, 08:55 PM
Originally posted by han freak solo:
My memory may be wacked, but I thought excessive fuel mixture provides a poor but reasonable cooling benefit for an engine. Fouls plugs, too.

I guess that could help bring home a damaged engine???????

Yep, at least in real life. Good thinking. I'll have to try that on my next limp home...

Tully__
08-25-2005, 09:18 PM
In real life, full rich gave better cooling for prolonged high power settings (max climb power for example). At anything other than max power, full rich settings will foul plugs quickly and at cruise power it uses way too much fuel. 120% represents "Full Rich" in those aircraft whose mixture controls were set up that way.

In the game there's effectively no need for it if you manage your cruise power settings correclty, the altitudes we're climbing to are much lower than those historically used on long range escort or short range intercept missions of high altitude bombers.

IL2-chuter
08-26-2005, 01:56 AM
As noted above, in RL it was for extra cooling, but it only works in pressure carb (mechanical throttle body injection, of sorts) or standard carb equipped engines. The blower is downstream from the carb so you can guess how this concept works. Go to max boost (or overboost) and you might get detonation caused by too much heat in the compressed air from the blower going into the cylinders . . . with 120% mix you get additional cooling. This was one reason why the US stayed with pressure carbs - you put your fuel to work before you burn it. Oh, and it was easier and cheaper . . .


http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

x6BL_Brando
08-26-2005, 04:13 AM
You need to reduce the fuel mixture to 80% to avoid starving the engine.

I think 'starve' has the opposite meaning m8. Starvation typically refers to a lack of fuel in an internal-combustion engine. I think the correct term is 'choking' or perhaps 'over-enriching'. Starving refers to running with too 'lean' a mixture.
I apologise for picking you up on it J - I certainly agree with the body of your post.

WOLFMondo
08-26-2005, 04:51 AM
I don't know if its in the latest patch but in a Ki84, changing the mix from 100 to 120 at altitude will blow up your engine, quite literally.


Originally posted by Tully__:
In real life, full rich gave better cooling for prolonged high power settings (max climb power for example). At anything other than max power, full rich settings will foul plugs quickly and at cruise power it uses way too much fuel. 120% represents "Full Rich" in those aircraft whose mixture controls were set up that way.

In the game there's effectively no need for it if you manage your cruise power settings correclty, the altitudes we're climbing to are much lower than those historically used on long range escort or short range intercept missions of high altitude bombers.

Thats odd, have you tried 120% mix on the Corsair? It makes the engine overheat quicker.

Aero_Shodanjo
08-26-2005, 06:21 AM
can someone test the La-7 (both version) 120% mixture settings max alt? IIRC it has a much higher alt where you still can engage 120% mixture compared to other planes.

I'd like to test it myself but Im still away from my PC for a couple of days.

effte
08-26-2005, 06:30 AM
Running an engine rich will reduce the risk of detonation and cool the engine. This applies regardless of carb type and even for fuel-injected engines.

The cooling comes since energy is used to vaporise the extra fuel.

neural_dream
08-26-2005, 07:54 AM
And <span class="ev_code_YELLOW">in game</span>? Do you see the temperature decreasing when in 120%? Also, I suppose that the rate you lose fuel is increased by exactly 20%, at least theoretically.

Salfordian
08-26-2005, 09:32 AM
Originally posted by JG53Frankyboy:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by fordfan25:
with gas prices the way thay are there should be sttings for -120% lol
gimme your US prices http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

i paid 1,36 " today the LITRE (!) , and i have a 75litre tank in my mercedes http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

Tell me about it, 0.95(1.39Euro/$1.72) per litre for diesel (4.31/6.32Euro per gallon, $6.50 per US gallon). At this rate I'll never afford the new pc for BoB http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

IL2-chuter
08-26-2005, 11:09 AM
Originally posted by effte:
Running an engine rich will reduce the risk of detonation and cool the engine. This applies regardless of carb type and even for fuel-injected engines.

The cooling comes since energy is used to vaporise the extra fuel.


Cooling with 120% fuel mixture in the cylinders (direct fuel injection) is very much less effective than 120% at the blower. Thats why direct fuel injected engines use a seperate injector ahead of the blower (water, MW50, nitrous or fuel) for additional cooling. The advantage of direct fuel injection is superior throttle response (better metering is debatable).

Tully__
08-27-2005, 11:43 PM
Inappropriate use of full rich in real aircraft can lead to detonation problems. If used at low power settings carbon deposits form in the cylinders. These in turn produce hot spots that can cause the engine to "diesel" with rather nasty side effects (broken big end bearings, holes in pistions etc...). I don't know how much of this behaviour is modelled in the game as I pretty much never use 120% mix.