Frosti

Radiator, Prop pitch, Mixture, what is this?

27 posts in this topic

Radiator - in game this can be set 0% to 100%, Im guesing it is cooling the engine? are there any reasons to not keep it 100% all the time?

Prop pitch - something about propeller resistant to wind? any reason to not have it 100% or automatic all the time if possible? (Im guesing you can set this 0% when going down from high altitude to not burn down the engine)

Mixture - 20% to 120% - no idea always got it on 100%

Know something more about those things?

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Radiator/Cowl flaps: These are indeed for cooling the engine. Opening them cools the engine (100%) closing them will make them heat up again (0%). High temps aren't good, but neither are low temps.

Prop pitch: it's the angle of the propeller blades relative to their motion (in short). Different flight phases have different pitch settings at which the propeller is most efficient. In take off they should be full for example, but reduced during cruise.

Mixture: The Fuel/Air ratio going into the engine can be set with this. It increases or reduces the amount of fuel (air stays the same). Increasing mixture increases fuel flow, but also slightly cools the pistons. Decreasing it reduces the FF, but there'll be an increase of temp.

Most of these are more important during long cruise phases than short dogfight missions, mainly reducing the fuel consumption and thus increasing the range.

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Radiator - in game this can be set 0% to 100%, Im guesing it is cooling the engine? are there any reasons to not keep it 100% all the time?

Prop pitch - something about propeller resistant to wind? any reason to not have it 100% or automatic all the time if possible? (Im guesing you can set this 0% when going down from high altitude to not burn down the engine)

Mixture - 20% to 120% - no idea always got it on 100%

Know something more about those things?

Radiator/Cowl flaps: These are indeed for cooling the engine. Opening them cools the engine (100%) closing them will make them heat up again (0%). High temps aren't good, but neither are low temps.

Prop pitch: it's the angle of the propeller blades relative to their motion (in short). Different flight phases have different pitch settings at which the propeller is most efficient. In take off they should be full for example, but reduced during cruise.

Mixture: The Fuel/Air ratio going into the engine can be set with this. It increases or reduces the amount of fuel (air stays the same). Increasing mixture increases fuel flow, but also slightly cools the pistons. Decreasing it reduces the FF, but there'll be an increase of temp.

Most of these are more important during long cruise phases than short dogfight missions, mainly reducing the fuel consumption and thus increasing the range.

My understanding of adapting the radiator is dependent on the drag you are willing to take at the expense of maintaining the optimum engine temperature. The more open the radiator is, the more wind resistance you will take.

All the forces on the engine creating stress can be eased by setting an optimum propeller pitch. I believe the 'higher' the propeller pitch in a dive will help to reduce over-accelerating the crankshaft. I believe the simulator represents higher pitch as a lower percentage and higher percentage for a lower pitch. Higher the pitch (lower the percentage) for level flight and higher (lower percentage) even more for diving. Lower the pitch (higher the percentage) for climbing. Confusing but I think that's the way it is meant to be explained. Correct me if I am wrong.

To follow on from the above point about mixture. The higher you are in the atmosphere the less air, and so the mixture ratio will become uneven and go over the optimum, and vice versa for lower you are in the atmosphere. Some planes will have a super/turbocharger which is used at high altitudes to compress air to fully utilise the potential of the engine. Adjusting the mixture so that it is thinner as you gain altitude and increasing as you descend - as a super/turbocharger is initiated, you can then increase mixture again.

EDIT: To follow on about the super/turbo charger, it is best to only use it at high altitude. Most planes will have their own guidelines about these quirks.

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Very informative posts,Im still learning all this engine controls.I also would like to know what is manifold pressure,from all the videos I've seen the manifold pressure is increased/decreased to change the engine power,does it have to do with throttle?Enlighten me if you can please.

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Very informative posts,Im still learning all this engine controls.I also would like to know what is manifold pressure,from all the videos I've seen the manifold pressure is increased/decreased to change the engine power,does it have to do with throttle?Enlighten me if you can please.

Manifold pressure is something tricky to understand. Basically, it represents a power setting. So references for take-off, cruise, etc. are all based on manifold pressure. E.g. in a Seneca you set 38" of manifold pressure for take-off, and about 32" for cruise (depending on some things). So what RPM's is for fixed pitch propeller aircraft (like Cessna's), is manifold pressure for variable pitch aircraft (warbirds :) ).

(skip this if you don't care what it actually is)

The measuring of manifold pressure is done somewhere in the air feed to the engine. The engine is always in need of air, an it sucks this in, kind of like a vacuum pump. This creates a flow of air through the induction system. Engine off, the pressure in this system should be very close to ambient air pressure, since there's just stagnant air in there with direct contact to the outside air. When the engine is running, though, the air is flowing, creating a lower pressure than outside. This is what the MP probe measures, it's nothing else than measuring an amount of suction.

Airplanes without turbo-chargers can't have a MP higher than the local ambient air pressure, since the air in the intake is just air taken from outside, nothing else. In a running engine it'll usually be lower. Turbo-charged engines, however, can compress the air, creating a pressure higher than the ambient air pressure. This is what enables them to have more oxygen at higher levels than non-turbo-charged engines.

(/skip)

MP is directly controlled by the throttle lever. Higher throttle setting -> Higher MP. This is because at higher power settings, the engine needs more air.

Just as a side note: Throttle is what controls the amount of air into the engine. Mixture is what controls the amount of fuel into the engine.

My understanding of adapting the radiator is dependent on the drag you are willing to take at the expense of maintaining the optimum engine temperature. The more open the radiator is, the more wind resistance you will take.

All the forces on the engine creating stress can be eased by setting an optimum propeller pitch. I believe the 'higher' the propeller pitch in a dive will help to reduce over-accelerating the crankshaft. I believe the simulator represents higher pitch as a lower percentage and higher percentage for a lower pitch. Higher the pitch (lower the percentage) for level flight and higher (lower percentage) even more for diving. Lower the pitch (higher the percentage) for climbing. Confusing but I think that's the way it is meant to be explained. Correct me if I am wrong.

To follow on from the above point about mixture. The higher you are in the atmosphere the less air, and so the mixture ratio will become uneven and go over the optimum, and vice versa for lower you are in the atmosphere. Some planes will have a super/turbocharger which is used at high altitudes to compress air to fully utilise the potential of the engine. Adjusting the mixture so that it is thinner as you gain altitude and increasing as you descend - as a super/turbocharger is initiated, you can then increase mixture again.

EDIT: To follow on about the super/turbo charger, it is best to only use it at high altitude. Most planes will have their own guidelines about these quirks.

Radiator: Yes, opening it increases drag a bit, since you'll open certain flaps/intakes (depending on design) to let more air pass through the engine.

Prop pitch: This directly controls the RPM's of the propeller, so it can be used to reduce stress, as you said. Increasing prop pitch also reduces overall drag, which might help a bit in a dive. The problem with a low pitch setting is that you can't set a high Man Press. Well, you can, obviously, but this will strain the engine. I was going to try and explain this in a short way, but that's quite difficult. Just remember that if you want to apply high MP (throttle) you should first increase the propeller pitch. If you don't, basically not all the power produced by the engine can be used by it, since it won't be transferred to the air as efficiently.

In a dogfight, leaving it at full forward is the safest way to go, unless you actually remember to set it to full after a dive and stuff.

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Very informative posts,Im still learning all this engine controls.I also would like to know what is manifold pressure,from all the videos I've seen the manifold pressure is increased/decreased to change the engine power,does it have to do with throttle?Enlighten me if you can please.

MP is the measure of throughput of air through the engine. It is proportional to the performance of the engine output. It is worth doing your own investigation to get an idea of what it is about. I find it difficult to articulate.

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Thanks Seraph and D3faye,Im gonna keep reading about it to better understand it.

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as i understand it you should decrease mixture to 80% above 3000 feet although im not sure about these values.

prop pitch works like the gears on a bicycle, a low prop pitch is like a high gear on a bicycle.

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From what I read on internet this prop pitch thing is to save fuel on long flights and main reason - to help save the engine when RPM goes too high.

But in game you really should keep it "100%" and never worry about it couse you gotta try really really reaaaaly hard to destroy engine with too much RPM's.

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From what I read on internet this prop pitch thing is to save fuel on long flights and main reason - to help save the engine when RPM goes too high.

But in game you really should keep it "100%" and never worry about it couse you gotta try really really reaaaaly hard to destroy engine with too much RPM's.

I am not sure I agree with you on this one. Also, adjusting the prop can give you greater speed, not just keep the engine at peak.

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I am not sure I agree with you on this one. Also, adjusting the prop can give you greater speed, not just keep the engine at peak.

The prop pitch can be changed to keep the prop efficiency to the maximum. Basically keep the Power Available/Power Applied the highest (Power Available being the actual power given by the engine, Power Applied being the power applied on the air). Different speeds and power settings require different prop settings. E.g., prop full forward is the most efficient for take-off, but when you're up to cruise speed the propeller will start to 'slip'. This is bad for efficiency.

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The prop pitch can be changed to keep the prop efficiency to the maximum. Basically keep the Power Available/Power Applied the highest (Power Available being the actual power given by the engine, Power Applied being the power applied on the air). Different speeds and power settings require different prop settings. E.g., prop full forward is the most efficient for take-off, but when you're up to cruise speed the propeller will start to 'slip'. This is bad for efficiency.

So after take-off you should decrease prop pitch?

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So after take-off you should decrease prop pitch?

During climb it's better to maintain full forward (unless you have performance charts). During cruise you should reduce it a little, but only towards, 80% or so.

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so.....in the heat of a dogfight, are you guys checking the instruments, changing cowl settings and moving the prop pitch to optimum...

or..

Just red lining untill the engine burns out, like me?

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Wow this is an awesome post, here we don't speak just about a game , you're great you all guys

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So after take-off you should decrease prop pitch?
During climb it's better to maintain full forward (unless you have performance charts). During cruise you should reduce it a little, but only towards, 80% or so.

I would say - increase prop pitch incrementally and listen to the engine. If it is struggling a lot, decrement the change. Eventually you will find what is best for your plane. I would not be dogmatic about specific settings myself.

so.....in the heat of a dogfight, are you guys checking the instruments, changing cowl settings and moving the prop pitch to optimum...

or..

Just red lining untill the engine burns out, like me?

Don't forget your radiator. Remember: Micro-adjustments to the PP make a significant difference on the engine.

The prop pitch can be changed to keep the prop efficiency to the maximum. Basically keep the Power Available/Power Applied the highest (Power Available being the actual power given by the engine, Power Applied being the power applied on the air). Different speeds and power settings require different prop settings. E.g., prop full forward is the most efficient for take-off, but when you're up to cruise speed the propeller will start to 'slip'. This is bad for efficiency.

I am aware of that. In effect fighting towards maximum efficiency is getting more out of the engine, thus more speed. But thank you for your reply.

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so.....in the heat of a dogfight, are you guys checking the instruments, changing cowl settings and moving the prop pitch to optimum...

or..

Just red lining untill the engine burns out, like me?

Are you telling me the big red "ENGINE OVERHEAT" warning isn't something we're supposed to ignore? I don't even see it anymore... :(

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Are you telling me the big red "ENGINE OVERHEAT" warning isn't something we're supposed to ignore? I don't even see it anymore... :P

even in WWII pilots had to manage rudimentary 'systems' to get the most out of their planes - you cant really just ram the throttle full forward and leave it there...haha

Mixture control (fuel / air mixture) - you have to pay attention to altitude and engine temperature...a cold engine at sea level on a field will require full rich mixture (all gas and minimum air) because the outside air density is as high as it can be on earth so your engine has enough air without adding it to the fuel mixture.

(after the engine is warm - you would typically lean (reduce the amount of fuel to air) the mixture to keep the engine running smooth - full rich in a warmed up engine can do harm to the plugs and foul 'em - but just a little leaner than full rich - one or two notches is all -)

The Radiator - Open the radiator to taxi - full open - because on takeoff - the engine will work harder than at any other time in flight...unless you are chased.

after you are inflight you should be able to set the radiator at 20% open - expanding to 40% max for pursuit...or extend..because it will cool the engine

but the drag penalty can be too high slowing you down baby

Prop Pitch - The prop must be full forward on takeoff - its like first gear on a trail bike - you want all the engine torque into the prop for FULL acceleration and total

control on T/O

Once airborne - you adjust for best climb...reduce throttle and reduce prop pitch - like shifting gears on your trail bike - to let the engine work less hard on turning the prop but maintaining airspeed - your RPM should drop into the green powerband on the gauge and yet your airspeed should stay high..also lean the mixture as the need for more air at the fuel intake is greater as the air in the atmosphere outside your plane is reduced the higher you fly...in R/L you can listen to your engine and hear peak performance and then check the temp. gauge to make sure you are rich enough to keep the cylinder heads in the green...

Do all of these adjustments and trim for true straight and level flight long before you reach the combat zone - this is why inflight spawning in this or any other sim should be in a place far enough from combat to get it done...flying an un-tuned guitar is a sure way to get kilt

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Are you telling me the big red "ENGINE OVERHEAT" warning isn't something we're supposed to ignore? I don't even see it anymore... ;)

I did try to play a little with prop pitch and radiator and... I actually destoyed the engine - after some time of switching prop pitch and radiator maximal speed of plane was greatly reduced and engine were too weak to go above 1500 meters.

This can be game bug I dont know. But I suggest to ignore this "ENGINE OVERHEAT" and only reduce engine power to cool down engine a little when you have time - couse touching prop pitch or radiator is slowly but effectivly destroying your engine more then overheating.

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I did try to play a little with prop pitch and radiator and... I actually destoyed the engine - after some time of switching prop pitch and radiator maximal speed of plane was greatly reduced and engine were too weak to go above 1500 meters.

This can be game bug I dont know. But I suggest to ignore this "ENGINE OVERHEAT" and only reduce engine power to cool down engine a little when you have time - couse touching prop pitch or radiator is slowly but effectivly destroying your engine more then overheating.

Ok - are you flying the Me109 series?

because they have an automatic system for prop pitch and mixture that you must learn to properly override if you choose to manually manage it.

activating 'prop pitch' control on the Me109 brings this message : automatic prop pitch control disabled

at this point - if you do not know what you are doing - you will fry the DB engine in very short order

best to leave the 109's engine controls alone until you figure it out - you can read Il2 forums (use search) and other historical documents to learn about manual engine controls WRT the Me 109's

side note: the P-51 in this game has an auto mixture control - your manual adjustments allow only to switch between 100% and 120% full rich..the Mustangs auto system does the rest

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It would be nice if we started to collect all the info that is being posted in threads like this and add them to a sticky so new (And old players alike) can easily find this info for future references. Very nice posts from d3faye, Ancient and heywooood.

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As for mixture and supercharger:

- yes it works in Wings of Prey - to climb above 5,000 meters with plane without automatic mixutre you have to reduce mixture to 60%, 40%, 20% and turn on supercharger. Talking about plane that allow you to reduce mixture that much - Yak-3 exemple.

But Wings of Prey is really forgieving about that, in other game :( if you do not reduce mixture when you are climbing, plane never gonna go up or even engine will be on fire from overheating.

Also on low altitude increasing mixture to 120% add some 'power'.

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side note: the P-51 in this game has an auto mixture control - your manual adjustments allow only to switch between 100% and 120% full rich..the Mustangs auto system does the rest

If WOP is historically accurate , in the P-51 D is better to simply never change the mixture, since the automatic simmons system will use your altitute value to set the optimum value.

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