View Full Version : Optimum engine management.

12-29-2010, 05:35 PM
I am trying to learn how to properly manage my plane on max realism and could use some tips. I understand how the mechanics work but not how best to make use of them.

What's the best way to hit top speed when cruising along in a combat area? Should I go 110% with open rad or cut back the throttle to avoid the drag? Is it ok to go open rad in dog fights or should I try to keep it closed as much as possible?

What about prop? Is 100% fine or should I cut it back to 90-95%? How important is it to lower prop during short 'boom and zoom' attacks on targets at lower altitude?

I'm under the impression that I need to decrease mix as I gain altitude too. Can I ignore until I'm spewing grease or do I need to keep an eye on it at lower altitudes too? Generally speaking, is there a certain amount I should be decreasing it by per 1km?

Thanks for any help.

12-29-2010, 07:11 PM
Cruising in combat area as opposed to in sight of enemy and fighting, run military power around 90%. With engine reliability set ON you don't want to push the extra as a matter of course.

12-29-2010, 08:13 PM
Hey Andrew,

There are some elements of engine management that have a significant impact on performance, and some that only make a marginal difference.

Taking care of the fuel mixture is very important for aircraft that don`t do this automatically. Soviet aircraft are particularly picky about having the correct mixture settings. You want to fly with the richest mixture possible and you can ignore the mixture setting until you see smoke, at which point you will also hear your engine sound differently and probably feel your aircraft`s performance drop.

There is no general rule as to when to decrease the mixture, for example most Yaks can fly on 100% mixture up to about 4400m or so, while the MiGs can fly on 100% up to nearly 7000m I think. Most of the British and all of the German planes either have their mixture settings automated or can fly on 100% at any height. Many of the US or Japanese planes have a setting of 120% or 100% only; setting the mixture at 120% gives the plane a little boost on takeoff I think (important for carrier take-offs), but the US and Japanese planes` mixture needs to be reduced to 100% very quickly.

Supercharger stages also affect engine performance greatly with altitude; make sure you know at what alts you need to change them. Some planes have only one stage, many have two, some have three, and some (all German and most British planes I believe) have the switching of the stages automated.

Closing the radiators will give you a tiny speed boost and I think it may also protect radial engines a bit, but you`re probably all-right flying around with your rads open all the time; closing them will make your engine overheat quickly. I close my radiators only when I need every last bit of speed in a straight line chase or run away from an enemy.

Prop pitch makes a little bit of difference to performance, but it`s mainly a way of keeping your engine cool. If you leave it at 100% or on auto (for planes that have it), then you will be fine 99% of the time. You want the pitch to be 100% or auto in combat at all time, and if you are new to this game then you probably want it at 100% or auto as soon as you see an enemy dot; at that point you have better things to worry about than fiddling with the pitch. It`s possible that setting the pitch to less than 100% in a steep, long dive that takes you beyond your plane`s maximum level speed at that altitude will let you enjoy a minor speed increase, but it`s negligible if true. The only time you should be lowering the pitch below 100% in most planes is if you are cruising far from enemies or the combat zone, and you want to cool your engine.

12-29-2010, 08:16 PM
Originally posted by Woke_Up_Dead:

Closing the radiators will give you a tiny speed boost and I think it may also protect radial engines a bit, but you`re probably all-right flying around with your rads open all the time; closing them will make your engine overheat quickly. I close my radiators only when I need every last bit of speed in a straight line chase or run away from an enemy.

Depends on the aircraft. The Lagg for example handles like a dog at low speed with radiator open, wallowing all over the sky.

12-29-2010, 10:44 PM
If you're aiming for realism I suggest using your guages to help determine the proper settings.

All aircraft have an optimum RPM for cruising. Determine the proper RPM for your aircraft and adjust your prop pitch accordingly. For the SBD-3 it's 2500 RPM at takeoff, 2300 RPM for climbing and 2000 for cruising.

Also, as you climb keep an eye on your manifold pressure. If it starts to drop than it's time to adjust the mixture and/or change supercharger stages.

12-30-2010, 12:53 AM
Read this, very helpful.

http://mission4today.com/index...Base&op=show&kid=249 (http://mission4today.com/index.php?name=Knowledge_Base&op=show&kid=249)

01-03-2011, 07:52 AM
Determine the proper RPM for your aircraft
How does one do that?

01-03-2011, 08:31 AM
if the game does care any realworld numbers about manifold pressure, mixture and pith settings is questionable............... you sure can use them if you know (or have a pilotsmanual) them !
but i doubt you will get the desired performances, at least in the most IL2 planes.

<- IMHO !!

01-03-2011, 10:45 AM
p51 works well in game with these real world numbers,


Take off: 1490HP at 3000rpm (~40"Hg)

(at 13k feet) 1590HP at 3000rpm at 61"Hg

(at 27K feet) 1370HP at 3000rpm-61"Hg


Take off Max: 61" at 3000rpm
War Mergency: 67" at 3000rpm
Militray power: 61" at 3000rpm
Max continous: 46" at 2700rpm
Max Cruise: 42" at 2400rpm


Manifold Pressure: 29-37"Hg

RPM: 1850-2320

MAX airspeed is 505MPH.

i cruise around on military power with rads closed, and boy is she fast and no overheat whilst in a combat zone, and max cruise settings over friendly.

watching the gauges, it equates to 95 pitch and 95 power in level flight for military.

01-03-2011, 11:16 AM
Originally posted by andrew8412:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Determine the proper RPM for your aircraft
How does one do that? </div></BLOCKQUOTE>

Practice, practice, practice. As Frankyboy mentioned, real world numbers can't always be applied directly to the game. However, I've found them to be a very good starting place. Stick with one plane long enough and you'll find the sweet spots.

You can find climb and cruise data for most WWII era aircraft from many different sources. Google is good but takes a bit of sifting. There are copies of original pilot's manuals out there that are fairly inexpensive. You can even order CDs loaded with them. The manual that comes with this game even has some good data. Or search this forum for that matter (but expect to find varied opinions. Many, many, many varied opinions. Many.).

01-03-2011, 11:20 AM
Originally posted by andrew8412:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Determine the proper RPM for your aircraft
How does one do that? </div></BLOCKQUOTE>

Aircraft Guide.pdf that came with IL2:1946 has some notes under each cockpit layout including for speeds and engine settings.

For 1941 LaGG-3;
Pilot Notes:
Take-Off Speed: 150 km/h
Landing Speed: 140 km/h
Combat Engine Setting: 2,750 RPM
Best Cruise: 2,300 RPM
Economy Cruise: 2,100
RPM Prop Pitch Control: Manual
Mixture Control: Manual
Boost: No
Supercharger: Two-Speed

No, it doesn't say height to shift SC gear, but that's not hard to find out and it's not that high up.

I've not seen an update to Aircraft Guide.pdf, ever, perhaps Hardball's AC Viewer has the newer planes.

01-03-2011, 05:34 PM
Originally posted by andrew8412:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Determine the proper RPM for your aircraft
How does one do that? </div></BLOCKQUOTE>

I know this a lot to read, but just bear with me here... http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

There is no omnipotent, single proper RPM for any aircraft. The needs change depending on the situation.

It's an old analogy, but still a valid one: think of changing propeller RPM as changing gears in an automobile. You use different gears (different engine speeds) in a car for different driving situations.

Some simple examples:

> In a car, you'd use a low gear/high engine rpm, and a lot of throttle, for climbing steep hills. Obviously, when using a lower gear your potential top speed is reduced, but you're going uphill and you wouldn't be going as fast as you would on the level or downhill, so you make much better use of your available power by using short gears and opening the throttle.

The same applies for piston aircraft with adjustable pitch, constant-speed propellers. Look at the checklist of any such real world aircraft and it calls for high RPM and power settings during climbs, particularly initial climbs after takeoff.

> On the level: When making cross country drives on long, sparsely populated roads in an automobile, you would likely use top gear, and relatively little throttle, for the long cruise. You're using low engine RPM and low throttle. You're not generating a lot of power, but you don't need to in this case - you're able to go a long way at a fairly good speed. You're economizing the use of your engine for the long run, minimizing wear and tear and maximizing fuel economy. This is important in the sim now that we have a more realistic engine reliability model and if you fly long missions in the game.

Again, the same applies to piston aircraft with adjustable pitch, constant-speed propellers. Once established on the cruise, the checklists call for a pullback on both the propeller RPMs and throttle settings, for the same reasons as stated above, particularly for civil, non-combat aircraft. However, for combat aircraft that need to get somewhere in a hurry, and the destination is still some distance away, you want to use something called MCP, or Maximum Continuous Power...

> Acceleration, and moving as fast as you can: This is a straightforward process in a car. Floor the throttle, and make careful (or agressive!) use of the clutch while moving up through the gears. Of course, the point of going through the gears is to keep the engine RPMs within the "power band". Get the RPMs too low and you lug the engine, losing power and acceleration/speed. Too high and, while still making good power, you lose much of your available torque - very important for acceleration (and especially important for acceleration in propeller aircraft...). Go exceedingly high on the RPMs and you risk excessive engine wear, or even damage or failure.

Once aerodynamic drag overrules any further ability of attaining a higher speed, the throttle's wide open, you're in top gear, and the car's engine should be at a relatively high, but not terminally high RPM, and you're moving along at speeds that would get you jailed and without a license just as quickly! The engine's RPM should be in a "sweet spot", not too low, and not pegging on the limiter. Of course, the point of this is to simply get somewhere as fast as you can without destroying the engine in the process.

Well, guess what. The same applies to piston aircraft with adjustable pitch, constant-speed propellers. Mostly. The thing here is that in such aircraft, you have more freedom in how the engine's RPM's are managed. This means you can fine tune performance; vs. fuel economy; vs. aircraft speed, altitude, and attitude; to get the best out of a given situation. It also means you are given a lot of room to mess things up, and if you aren't sure as to how well a particular aircraft at any given speed, altitude, and attitude, with a particular engine and propeller installation, performs with certain applications of throttle, propeller, mixture, and supercharger settings, then messing things up will be all too easy to do and will occur all too frequently, often without you even being aware of it...

The simple part here is that if you want to move as fast as you can, open the throttle to 100% or more (depending on need), and keep an eye on the oil and/or glycol/radiator temps. Things get a bit more complicated with the application of the propeller speeds, though. Contrary to popular belief - at least in real life - maximum propeller RPM does not always provide for maximum aircraft speeds. It does yield best performance during acceleration for takeoff and from low airspeeds, as well as during climbs (just like similar situations in a car, remember?). That's why in aircraft checklists there are separate propeller and throttle settings for takeoff and for climbing. The former would be Takeoff Power, the latter is MCP, or Maximum Continuous Power. You could climb all the way to cruise altitude at Takeoff Power, but the engine will be the worse for wear because of it and temps would be dangerously high. MCP gives you the maximum available power and performance that can be sustained long term, and that is far less likely of ruining things prematurely, but still with a higher than desirable fuel consumption rate. Find this setting for whatever aircraft you're flying and use it for actual combat situations.

One of the things most commonly overlooked in discussions about piston-propeller aircraft performance is the aerodynamic torque applied to the propeller. No, not the gyroscopic spinning torque of the entire propeller assembly that makes the aircraft want to peel off in another direction (though in a way it is the same type of force), but the torque applied to the propeller blades themselves in respect to the angle of attack of the airflow flowing across them, all in conjunction with the operational efficiency of the engine. This can get a bit complicated to explain, so for now just think of the forces of BMEP as the same as the propeller's interaction with the airflow functioning as a clutch. This force can be measured by mechanical means and, like airspeed, altitude, etc., can be indicated as such by an indicator on the display panel (BMEP in ft/lbs, or Brake Mean Effective Pressure, if I recall correctly...). This gauge is common in turbo-prop aircraft. Such an indicator did not come into regular use until after the war, however, so in this sim you'll have you use your own intuition. Also, I don't know if the sim accurately models BMEP, but in practice it seems to make itself apparent when I fly and configure certain aircraft, the LaGG-3 series being a good testbed for this. Anyways, BMEP is very important in how an aircraft performs.

In short, and depending on the aircraft you choose to fly, maximum combat performance can be extracted from the engine and propeller by using 100% or more throttle (remember to keep an eye on the temps) and modulating the use of propeller RPMs, all depending on your present speed, altitude, attitude, and what you want the aircraft to do. In many ways, the propeller RPMs can significantly affect aircraft performance and engine temps. During immediate combat I'm messing with the prop lever more than the throttle lever, since - again during combat - I tend to set the latter to 100% and leave it there unless I need to slow down rapidly or cool things down a bit. If I need to make the best climbing performance, I'll raise the prop RPMs to maximum, or a couple hundred RPMs less, in the climb. If I need to make great haste in a shallow dive to gain a ton of speed, and I'm currently at a low speed, I'll initially set high RPMs for good acceleration, then pull back on the prop lever - but not too much - so that the propeller blades can take bigger bites out of the air and give me more speed! Doing this strikes a balance between a suitably high propeller RPM, and a optimally high alpha (angle of attack) for the propeller blades.

I never even got into managing mixture, supercharger, and radiator settings, which further affect aircraft performance. I think I've said enough by now, so perhaps someone else can detail those issues.

Of course, all of this is only academic and will be of no help if you don't practice, and practice - with the same aircraft - a lot. Most of us in the forums have played this sim for several years now and, frankly, it has taken that to be any good at flying the planes in the sim.

I hope I made some sense with all of this, and I hope it was helpful.

01-04-2011, 03:34 AM
Hi Treetop,

Good analysis on engine management http://forums.ubi.com/images/smilies/25.gif.

I would add two more power settings to the repertoire, MCP is just that, max continuous power, but not necessarily the most efficient in some circumstances, or best for overall engine health. A more conservative and arguably healthier setting for high engine output would be climb power, irl often around 85-90% power and 85-90% pitch, give or take.

The last power setting I would call 'coming home power', which would be about halfway between MCP and climb power. Very useful when you want to get back to base before dark in a floatplane... http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif