View Full Version : Radiator and prop pitch?

03-19-2004, 09:24 PM
Ok so what do these things do and when do you want to use them?

03-19-2004, 09:24 PM
Ok so what do these things do and when do you want to use them?

03-19-2004, 11:00 PM
You use prop pitch to "shift gears". That is by adjusting the pitch you can control your RPMs and maintain a cool engine and constant horse power (I could be wrong about that very last bit, I don't know much about engines). In level flight your RPMs are relatively stable, but if you then climb or dive the prop will now be grabbing less or more air respectively and so then the engine will be turning the prop more or fewer times. I fly the Spit and generally try to keep my RPMs around 2300. I don't know if that's optimal, but it seems to work. Anything over 2500 and I think you're straining the engine.

As for the radiator, it is used to cool the engine. The default position is closed, but if the engine overheats or if you've just been pushing it and you know its running hot and want to cool it quickly, open it up. In exchange for the improved cooling you'll lose approx 20kph from your top speed.

03-19-2004, 11:14 PM
Thanks do you or others use the default macros for these "manuvers" or have you come up with your own macros on a joystick? Are doing all these prop pitches really help with the engine or are you able get any other benefits?

03-19-2004, 11:27 PM
I'm not sure what you mean by macros. I don't think functions can be automated in IL2 if that's what you mean. However, I've got a Saitek X45 and am therefore blessed with more inputs than I could ever use and so I have prop pitch and radiator position set to a slider and a switch respectively.

As for other benefits, no it only ensures that the engine is running as I want it to, but then that means that I'm getting the most out of it at any given time thereby creating and allowing myself more energy to work with when I'm maneuvering against an opponent.

Maybe an example would help, however poor it may be...

I see a bandit 5km out. I enter a shallow dive and lower my prop pitch to from 63% to 56% to maintain 2400 rpms. In this way I'm not straining my engine, overheating it and reducing it's power output before engaging the enemy. When we've closed to within 800 meters I pull back on the stick and enter a steep climb so I set the pitch to 80%, and gun the throttle to 110%, stressing the engine for a few seconds in an attempt to maximize the effect of my maneuver. Those are not settings I could maintain for long, but it's a little something extra I can pull out when I need it. After the fight, assuming the skies were clear, I would open the radiator and allow my engine to cool in preparation for another bandit.

Make sense?

03-20-2004, 08:15 PM
OK i think i got calling macros and key definitions mixed up so i geuss my question was do you use the default settings or did experiment with better definitions. I have a side winder pro and lots of keys to do stuff with and i was looking for some ideas about ppls key (or button)definitions.

now continuing about this prop pitch, i noticed that in il2 fb when say i make a rapid change in altitude, most clearly when i make a sudden climb, that the plane "feels" and the sound of the engine almost stalls, even though it is not so steep that it would throw me into some kind of stall. Is this the effect of not piching the prop to counter the effect of my sudden change in altitude. Contrastly i never noticed this with IL2 original.

03-20-2004, 10:15 PM
If you're not adjusting your prop pitch and you go into a steep climb, the "stall" you hear is the drop in rpms.

As for not hearing this in the original IL2, I can't say because I started with FB. However some planes, I don't know exactly which but I believe the 109 falls into this category, have constant pitch props that will automatically maintain the engine's rpms without your input and so it may have been that you were flying one of these in IL2.

03-21-2004, 07:03 AM
Thanks a bunch for helping me sort this out http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

03-21-2004, 12:27 PM
I keep my radiator switch on that damned "pinkie button." It rarely hurts you to change radiator settings wider, and it's always good to have a cool engine, but the best way to do that is to throttle back whenever you can.



"Here's your new Mustangs, boys. You can learn to fly'em on the way to the target. Cheers!" -LTCOL Don Blakeslee, 4th FG CO, February 27th, 1944

03-21-2004, 08:41 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Malar07:
Ok so what do these things do and when do you want to use them?<HR></BLOCKQUOTE>

Here is some great info previously posted by "PYE" back in January on Variable Prop Pitch. This post is what got me to start using prop pitch. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-very-happy.gif It is easily understood and readily usable. I recommend printing it out to refer to till you get the hang of it and really understand it. I use it always now when flying available VPP aircraft.
The Variable Prop Pitch on a Bf109 Series can be set to Auto or Manual at any time before and during a mission.

Any New Pilot 'SHOULD' keep it set to AUTO until he/she is comfortable with flying and landing and general combat Manouvres. It does default to AUTO at startup so unless you change it, you are prepared to start.

Any attempt to try use Manual prop pitch management before you are ready could have long term negative affects and damage your confidence at wanting to become a proficient Pilot flying IL2:FB

Once you ask yourself 'What benefit can I get' or 'Why do others always use it?' then that is the time to start to learn and get to use it naturally as moving your Joystick throttle to get more speed.

ESSENTIAL Step Number 1

You Need 2 Buttons specifically assigned on your joystick for increasing and decreasing your Prop pitch angle.

These two buttons WILL be the most used buttons of all buttons (including keys ) you've ever assigned in any Flight Simulation you've ever had.

So with that in mind the best place is nearest your Thumb (on the hand that holds the joystick).

Because the Prop pitch values are Up and Down values. Ideally your buttons assigned should be positioned one above the other. The top button for Increase value and the bottom button for Decrease value.

These 2 keys are assigned IL2:FB keyboard SETUP. Then you should configer your Programable joystick to map to these keys.

The above is very important for comfort and ease of use. A Real pilot had a wheel that he could rotate with his left hand to increase and Decrease prop pitch when he needed.

Now go test for a test flight. Using Auto Prop Pitch ONLY take off and fly level. THis is just an excersise to find if you can comfortable using these two keys in during normal level flight or basic manouvres. Just practice using these two keys constantly. Click the up button 2 times, click the down button 3 times, click the up button, 4 times, down button 2 etc, different combinations of up and down.

Even though you aren't doing anything yet, You are preparing yourself for the natural movement of changing the prop pitch by reflex.

The stimulus for that reflex action will be be 2 things.
1) The sound of the Engine
2) the Dial in the cockpit that represents the Revs counter.

Essential Step Number 2
Knowing why WW2 Pilots use Pop Pitch

So now you're comfortable with this thumb movement using these two buttons, It should have become second nature, a kind of a nervous but controlled thumb twitch Up down, down up down down up etc.

Make sure you're on a Runway in the game and your engine is idling. 0 power setting.

Turn your Prop Pitch option to Manual.
(See your IL2:FB key control assignment for this)

Now click your thumb to decrease the prop pitch. It always Defaults to 100 percent. Clicking down and up shows the percent change in steps of 5 percent.

When you do this, the game is simulating the , Propellor Pitch or angle being adjusted mechanically.

Quick History lesson
Imaging the first planes ever made, Fixed Wooden props carved out of 1 chunk of wood. At a predetermined angle. Prop starts spinning and you get going flying. You fly level flight and thats perfect but if you start to climb your engine loses revolutions and therefore power, like a pedal bike or car going up hill with only one gear!! Argghh
History lesson over

The idea of gear change is not to stall when going to slow or to keep your engine from over rev'ing or our legs from going round so fast you can't provide anymore useful push on the pedal down stroke. ie, over-rev'ing (over-revolving) your legs

So because your prop is fixed in the same position your prop is trying to grab the same amount of air, as when you where flying straight and level. But the engine is under stress and losing more revs, due to it climbing. So Flicking your Prop Pitch control up from 75 percent to 80 percent in this example, will move the prop angle physically so as to grab less air, which means the Load on the engine is reduced and that will not make the revolutions drop to a critical stall speed.

It sounds complicated
but isn't!! (you knew I was going to say that!!! )

I now you want to fly and try ....... I can't stop you, so Off you go.... Try in a BF109 F4.

**DO NOT TRY Bf109 E4. This is for people with experience because it more sensative over revving and damages the engine very quick.

But first I Advise you to Set your Prop Pitch to 75% on take off. This will stop you damaging your engine on take off, keep the power setting at 70 percent, only using your Prop Pitch up and down buttons.

This is so you understand and feel and hear the effects that this setting have on your plane.

ESSENTIAL Step Number 3

So what did you Learn. You found out that when you click up (or increase prop pitch), your engine makes a louder noise, thats your engine revolving fast. If it revolves too fast it's called overrevving and will you damage your engine after a while. If you Lowered the percentage, you found the noise of the engine went down, thats because the engine revolutions have been decreased, the Prop is actually trying to 'bite' more air and the poor engine loses more revs and the work only gets harder for the engine , until it stalls!

Remember that the Throttle power settings aren't being used yet. Only to take off and and get your self in level flight to practice.

Essential Step Number 4

The objectives of Prop Pitch is to keep the engine running effiently ie. keep the engine cooler, when climbing, diving or just flying straight and running economically to conserve fuel.
it can be tuned to try and get the most speed it can, but also the prop can help reduce speed by creating more drag, when no engine power applied.

The Tachometer or Rev Counter

The Tach (as it is offetened shortened to can be viewed whilst flying in the WIDE view.
This allows you to see the tack whilst seeing the horison, the other views, can me used to get a closer view of the tack to find out what the numbers are.

The Tachometer shows how many revolutions per minute the engine is doing. Each plane cockcit may have it in a different place. But for the Bf100 F4 it is just right of the stick under the other dials. The Maximum we want to keep the needle is 25 that would mean 2500 revs per minute. Don't worry if you go over this temporary just reduce it to that 25 Golden figure. You are Better keeping it just under 25 if you can't get it dead on than just above it, to be on the safe side!!

Now you know what to look for in the cockpit as you fly, try again flying level and You will notice the Engine sound will change as it passes the 25! It sounds more stressed! of course it's running faster than it should. That will be your Audible signal to lower your revs. After a while practicing you will recognise the sounds naturally, without looking at the revs and lower your revs by reflex.

I will quote another Pilot wrote how he practiced. He describes the thought process that goes into controlling the Prop Pitch from level flight.


Quote :

"I used the Bf109 F4 and started a quick mission with just the F4. I turned on the "Wide-View" so I could see the tack (RPMs) without having to change my view to see it. I then set my throttle to 85% and never touched it after that. Then using the prop pitch increasing or decreasing as needed I kept the RPMs at the 25 mark (2500) flying level. I then started a climb and noted that the RPMs started to drop so I increased the prop pitch to keep the RPMs at 25. Once I leveled back out the RPMs started to climb so I decreased the prop pitch to keep the RPMs at 25. If I started a dive the RPMs would increase so I decreased the prop pitch to keep the RPMs at 25. Remember don't touch the throttle when doing this, keep it at one setting and just use the prop pitch.

This helped out for me. I just kept doing it, climbing, diving and flying level. The whole time keeping an eye on the RPMs. I just chose the 85% and 2500 RPMs just for getting used to prop pitch."

So after a while you end up controlling your prop Pitch naturally and instinctivly and this will add another advanced aspect of your flight simulation that in return is very rewarding to use. The AUTO settings is great, but if you want to get a little bit more power out of your plane, as in a manual car, giving you the choice to change up to a higher gear when you want - then Manual Prop pitch is for you.

Extra Information about Constant Speed Propellors

Other aircraft use different systems. Most common being the Constant Speed Propellor.
Both Variable Pitch and Constant Speed Propellors ARE BOTH variable pitch propellors!!

But the Constant speed propellor has the advantage that the Pilot sets the revolutions that he wants and the prop pitch is changed automatically! nice hey!

The term "constant speed" refers to a refinement in which the 'pilot' sets a rotational speed (RPM) at which he wants the prop to operate. Then a "governor" (a mechanical device to you and me) operates to maintain this speed. This 'governer' sits inside the propellor hub and moves the Prop Pitch automatically to maintain the pilots chosen RPM setting.

So for us pilots we can can set any rev limit we want (within limits, Of course!) without fear of over-revving the engine during combat manouvres. It can be set High revs for more Power or lower revs for Fuel Economy.

Obviously you don't want to run constant Speed propellors at a too high a Revoluton per minute (RPM) for too long also because it will over heat the engine and damage it.

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