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Slickun
04-15-2006, 09:37 AM
Specifically for the P-51.

I'm finally going to try to get up to speed with complex engine management.

Can some of you good folks either:

a. Point me to a good discussion or walk through with this (I know I've seen them, just never paid attention http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif)

b. Be so kind as to post your own ideas, tips, procedures?

Thanks. It's an ongoing process. I've finally gotten a set up where I can be more than a casual player (my own dedicated PC). I've sworn off of wonder woman view, and am now ready to ulp go with complex engine.

Heck, someday I may even swear of of unlimited ammo. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

danjama
04-15-2006, 09:58 AM
Well there isnt really much to do with the P51 and CEM. The only difference is i think that you can change prop pitch, and im not even sure of that as ive never used CEM off. There is no manual supercharger and no manual mixture. The only time i change the Stangs PP is on landings when i fluctuate between 30% and 50% depending on airspeed, altitude and position according to the runway. Apart from landings, i always leave the PP at 100%. Maybe Mustang "experts" can tell you more about manipulating the pitch for better perofrmance but i cant think of any advantages it has in the game (as opposed to real life where it was used to maximise fuel efficiency).

Slickun
04-15-2006, 10:31 AM
Right. Mixture and supercharger are auto.

What/why does one change prop pitch?

danjama
04-15-2006, 10:35 AM
Someone else could explain it better but in real life it was used to make the engine work more efficiently. But we dont need to worry about mechanical failure, fuel management or other technical engine issues like they did in real life. In the game, as i said, i only use it for landing, e.g. lowering it to 30-50% on landing approach to help slow the plane. Other than this, i know of no other real advantages in changing the P51's propeller pitch. However, others may know of some benefits. Maybe it can be used to manipulate speed retention/gain/loss in dives and climbs, im not sure.

StG2_Schlachter
04-15-2006, 10:39 AM
Contrary to danjama i suggest you set PP to 90% or higher on take-off and landing to have maximum power available for a go around if needed - on all planes.

Since most allied planes have constant speed propellers,CEM it is not that important when flying those. At least not in this simulation. In real life, the engine had operation limitations for long range flights which were not to be exceeded, i.e cruise manifold pressure and revolutions per minute settings. But this means nothing in FAP. You can fly your plane with 90% power and pitch until you run out of fuel.

I don't fly the Mustang very often. So I can't give you any further advice...

Prop. Pitch changes the angle of attack of the blades "digging" into the air. Do a Wikipedia research on Propeller Pitch.

domenlovrec
04-15-2006, 10:52 AM
Fly 100%PP all the time if you want max performance. Propeler pitch is wrong term. It can be used only for Bf109, where you actualy turn blades of prop. Other ac don't have it, by "prop pitch" you set engine's RPM. So 100% means max RPM. However you can use lower PP if you're short on fuel or have heat problems.

danjama
04-15-2006, 10:56 AM
Originally posted by StG2_Schlachter:
Contrary to danjama i suggest you set PP to 90% or higher on take-off and landing to have maximum power available for a go around if needed - on all planes.


That is a good point but i have pitch controls mapped to my joystick so i can increase and decrease "on the fly" if i need to.... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Matz0r
04-15-2006, 11:57 AM
Originally posted by danjama:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by StG2_Schlachter:
Contrary to danjama i suggest you set PP to 90% or higher on take-off and landing to have maximum power available for a go around if needed - on all planes.


That is a good point but i have pitch controls mapped to my joystick so i can increase and decrease "on the fly" if i need to.... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>


That's nice, but no planes in IL2 will give you instant power. So in an emergency situation having the controls conviniently placed wont save you. Also having higher prop pitch when landing helps you "air brake" by pulling back the throttle.

On the prop pitch, general rule is:

Climb: Higher prop-pitch (100%)
Dive: Lower prop-pitch

In most planes I cruise at around 70-80% prop-pitch.

StG2_Schlachter
04-15-2006, 12:06 PM
Originally posted by domenlovrec:
Fly 100%PP all the time if you want max performance. Propeler pitch is wrong term. It can be used only for Bf109, where you actualy turn blades of prop. Other ac don't have it, by "prop pitch" you set engine's RPM. So 100% means max RPM. However you can use lower PP if you're short on fuel or have heat problems.

Not true. The method of adjustment is different, but you still change the pitch (or AoA) of the propeller blades when the aircraft has a CSP. But in the case of a CSP you don't have to continuosly readjust the pitch when the aircraft speed changes or the throttle

RCAF_Irish_403
04-15-2006, 03:22 PM
If you lower PP
1) Less wear & tear on the engine
2) conserves fuel
3) helps u go faster in a dive

Raising PP
1) helps u climb
2) can act as an air brake

Slickun
04-15-2006, 04:03 PM
Thank every one very kindly for the info.

So. I'm coming in for a landing, a bit hot, lowering PP will help me dump speed?

Nice to know.

BfHeFwMe
04-15-2006, 04:11 PM
Use the prop pitch to control engine Rpm, merlins overheat running above 3000 Rpm's. 100% pitch runs you more than 3000, so draw your own conclusions, or open up the rads and suffer the drag consequences. Tip, you can fly as fast or faster with rad's closed and power in combat with a properly set prop, than some knuckle head with full wep, full pitch, and rads wide open roasting his engine up.

To use it for slowing down, you have to pull back both engine and propeller, let Rpm's drop, than push the prop back up to 100%. Combine that with a bank or nose up three degree's and watch the airbrakes lock up.

horseback
04-15-2006, 07:08 PM
I believe that the CSP on the Allied planes is poorly modelled; as has been mentioned, in the real thing the prop pitch setting was for rpms. I get the distinct impression that you set the rpms and then just manipulated the throttle according to need most of the time.

However, I don't KNOW that for sure. What I do know is that in game, it flies a lot better if you keep an eye on your rpm gauge and try to keep the needle in the green band, as close to its middle as possible. Like your car or truck's engine, the Merlin has a 'power band' or rpm range at which it generates the most power.

That green band on the rpm gauge is the power band, and you want to keep your rpms in that band as much as practical. I try to 'gear up' or 'gear down' within that band to acellerate or slow down using the prop pitch and throttle. Of course, when I am going all out, everything's pushed up to the maximum, but like trying to go 70 mph in third gear, there's a point of diminishing returns, and you'll find that lowering your prop pitch 15-25% will give you more speed.

I don't know what kind of controller setup you have, but on my CH Pro Throttle, I have Prop Pitch controlled by button assignments: one each for Increase and Decrease PP, and one each for 0% and 100%. The Increase & Decrease buttons are opposite each other on a 4-way hatswitch right at my thumb, the 0 & 100% buttons are by my left pinkie. I'm taking a serious look at building a throttle quadrant with an axis assigned to prop pitch, but at the present, this is what is most practical for me.

Hope this helps.

cheers

horseback

Slickun
04-16-2006, 07:05 AM
I've got PP on a slider on my Mark 45. It was originally set for aileron trim, but its too sensitive and the keyboard works MUCH better.

Its all very confusing, HB. Are you saying that the throttle in US planes controlled PITCH? Now, that's interesting.

I was thinking that there was some sort of complicated algebraic formula everyone learned between rpm (throttle), pitch, and mixture to get to different speeds.

My Pop would talk about it, but he'd lose me.

StG2_Schlachter
04-16-2006, 07:20 AM
Originally posted by Slickun:
Thank every one very kindly for the info.

So. I'm coming in for a landing, a bit hot, lowering PP will help me dump speed?

Nice to know.

Yes, but IL2 is a little bit confusing at this.
If you set your pitch to 100% in game, the pitch of the propeller is at the lowest position possible, i.e. smallest angle of attack.
A setting of 0% gives you the highest pitch setting, i.e. highest angle of attack.

So setting 100% pitch has a braking effect at low speeds. This is especially true for the Bf-109. But be careful. Setting 100% pitch in an approach above 300 kph will damage your engine.

I suggest you practice Prop. Pitch and landing with a 109 "Emil".

For a beginner, a 2 point landing with the main wheels first is recommended.

So with a 109, approach the field at 300-500 meters above groundlevel. Slow down to 250 kph, lower gear and flaps to 2/3 (start setting in IL2) and keep around 30% throttle with 100% pitch. On the final drop flaps to full downward position and establish an approach at 180 kph.
Minor throttle correction may be necessary.
On short final, before crossing the runway threshold, rise into a 3 point attitude and increase throttle to flare. The speed at this point should be 160 kph. Gradually decrease throttle to lower all 3 wheels gently onto the ground. The speed at touchdown is between 160 and 140 kph. Slow down by pulling the stick towards you and carefully use the toe-brakes.
Be gentle with the braking or otherwise you will flip over.

danjama
04-16-2006, 11:18 AM
Originally posted by F16_Matz_:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by danjama:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by StG2_Schlachter:
Contrary to danjama i suggest you set PP to 90% or higher on take-off and landing to have maximum power available for a go around if needed - on all planes.


That is a good point but i have pitch controls mapped to my joystick so i can increase and decrease "on the fly" if i need to.... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>


That's nice, but no planes in IL2 will give you instant power. So in an emergency situation having the controls conviniently placed wont save you. </div></BLOCKQUOTE>

Well thats your opinion, it has saved me many a time and in fact has never failed me, tried, tested, and succesful. Thats good enough for me.

horseback
04-16-2006, 02:02 PM
Originally posted by Slickun:
I've got PP on a slider on my Mark 45. It was originally set for aileron trim, but its too sensitive and the keyboard works MUCH better.

Its all very confusing, HB. Are you saying that the throttle in US planes controlled PITCH? Now, that's interesting.

I was thinking that there was some sort of complicated algebraic formula everyone learned between rpm (throttle), pitch, and mixture to get to different speeds.

My Pop would talk about it, but he'd lose me. The physical mechanisms of the Constant Speed Propeller are pretty much beyond me, but from what I've read, the US and British systems allowed the pilot to set PP for a specific 'band' of rpms, and as he varied the throttle, the prop pitch would vary to allow the engine to stay within the desired range of rpms. So throttle didn't control pitch so much as engine rpms did. I get the impression that it was similar to an automatic transmission on a car, which is set up to 'search' for the best compromise between engine revolutions and throttle settings.

In your car, throttle settings act as a kind of limitation on the amount of power available to you; if you want to speed up, you push down on the gas pedal, and the transmission drops down and gives you more rpm until you reach the desired speed and you ease off the gas as momentum allows you to lower the rpms. The friction allowed by the transmission fluid determines your maximum rpm. A constant speed prop seems to work on a similar principle.

In a car, I think it has to do with the vicosity of the transmission fluid allowing the power of the engine to be translated down the drive shaft; CSPs came in both electrically and fluid controlled types (I think that Curtiss favored an electric control and Hamilton Standard went with the fluid controlled system).

In the game, however, you need to vary your prop pitch manually for max efficiency and speed. In US built aircraft, 100% prop pitch is analogous to 1st gear; it allows you to rev up your engine quickly in order to accelerate, but like 1st gear, it isn't the ideal setting for obtaining and maintaining top speed. At 100-110% throttle, if you gradually decrease your Prop Pitch to 80% or so, your speed will go appreciably higher.

If I plan on cruising around in a Mustang, I'll set the throttle at 80%, and gradually drop PP to 55-65%, for an rpm comfortably in the green band of the rpm gauge, around 2400 rpm or so. This gives me around 260-280 mph IAS, depending on my trim effectiveness and altitude.

To be honest, the dearth of campaigns appropriate for USAAF careers limits my P-51 time in-game, so my practices in this regard are generally derived from my P-40 time in Russian campaigns. It does appear to me that the same principles apply to the Mustang, P-47 and other US built aircraft, although I believe in game that the USN birds' CEM allows varying the mixture as well.

cheers

horseback

BfHeFwMe
04-16-2006, 05:08 PM
The 109 does not have a CSP in manual mode, your electrically controlling the blade angle directly. You also better know what your doing in the real thing, because it's possible to lose the prop in conditions like dives. In that respect it's the 109's that have poor modeling.

A true CSP takes inputs from airspeed, flyweights off the gearbox transfer shaft, throttle position, altimeter, and prop condition lever (prop pitch). By moving one of these inputs, you don't necessarily get a change in blade angle, the prop governor is going to weigh all the inputs, than make the adjustments to blade angle 'if required'.

Think of it this way, you as the pilot get two votes possible, throttle and condition lever. The rest you can cheat on a bit and influence by stick and rudder, forcing them into compliance with some of that fancy piloting stuff, airspeed and altitude. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Now are you beginning to see why you want to chop both throttle and pitch lever, throw a slight wing bank, and get the nose up a few degrees, than when RPM's drop to idle push the pitch lever back up to slow down with real braking action. The CSP works just fine, it's the other system that's been always a bit suspect. http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Low_Flyer_MkVb
04-16-2006, 05:15 PM
I've got my prop pitch on a slider. Seriously.

WWMaxGunz
04-16-2006, 07:31 PM
Horseback has got the best understanding of Mustang CEM while some others are misinformed.

Using PP, the engine will try to maintain revs by varying the actual prop pitch. The
mechanism I believe is hydraulic as in Hamilton Standard as opposed to electric as in
the Curtiss Electric and very direct. The moment the prop turns too fast or slow, the
pitch varies by force generated where with electrics it is like a thermostat with set
points seperated a bit so a delay going from too fast to too slow.

Definitely run high PP on takeoff and landings. That is fully realistic. You want to
keep the prop and engine at high revs for different reasons each one. For takeoff you
are slow and wanting to climb, the fine pitch gives you the most tractor at those speeds.
For landing you keep the prop fast and fine and adjust your power low, it gives you speed
control through throttle. If the power is less than can keep the prop turning at 100%
at the speed you are moving (very important) then the wind will drive the prop and make
extra drag. This is also true at high speed and esp in dives, you cut the PP and your
plane may well go faster, it is a matter of throttle and speed you have to get a feel
for to squeeze more out of.

Try some experiments. Run an approach except at 1000m alt. Start with cruising toward
slow and trimmed out at say 60% power and the same PP. Note your speed when it settles.
Now decrease power to 40% then raise PP to 100% and watch your speed and how you must
change trim (your first indicator of speed change) to stay level. Stay level for sure
or your results will throw you off, keep the view where you can see the VSI as opposed
to waiting for the speedbar to change -- 10m drop is a lot of energy for a heavy plane.

Another experiment is see how fast you can cruise at 90% power. Use the higher PP at
first and trim until speed settles then note the speed. Now cut the PP 5% and see how
you must trim to stay level then note your new speed.

A word about trim. It is essential. This is real. You fly real and you change trim
for every change in flight. You trim once maybe it is to get the plane to stop rising.
Fine but now the extra power that caused the rise moves the plane faster and from speed
making extra lift you rise again this time a bit slower. So you trim the nose down a
bit. In time you have it as close as you can. My best efforts at about 180kts in a
twin was to keep inside 50ft of target alt for some hours while the boss rested. I did
mostly about up to down +/- 20ft over many seconds per cycle with light fingertip pull
on the yoke as I pre-corrected whatever trend I was in. That is real and I did good.
In the sim I tend to be also rising or falling very slightly but it is harder to control
so fine and besides http://forums.ubi.com/images/smilies/784.gif you don't want to fly straight and level anywhere the
enemy may be. Still an understanding of trim and how you are flying is neccessary.

Practice low power flying offline with no enemy planes around you. You get good at that
with the CEM and your energy management and you will get better at high power too. Those
who just jump in and fight without doing that are really losing out. Going from another
sim or even another plane in the same sim (if the sim is any good) is enough different
to miss finding the edges you can get if you don't practice just the flying. It takes
however long it will to get where your hands move automatic for that plane. At low power
you have to work it more carefully and you will see sooner the results of your actions,
learn better how to squeeze more from your ride. That is where you really learn CEM.

BfHeFwMe
04-17-2006, 10:26 PM
Yes, prop is hydrolically powered, but what exactly do you believe meters the hydrolic flow. Does the term 'prop governor' sound familiar. How in your theory do you account for it? http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

WWMaxGunz
04-18-2006, 02:32 AM
My "Theory"?? http://forums.ubi.com/images/smilies/blink.gif

All I did was back when it all was explained in 2003, I looked at the diagrams and read more at
Hamilton Standard, Curtiss Wright and other AVIATION WEB SITES.

Here's a couple links:

John Deakin on variable pitch props.......
http://www.avweb.com/news/columns/182082-1.html

A site page exactly on IL2/FB props and CEM.........
http://people.ee.ethz.ch/~chapman/il2guide/cemguide/controllingrpm.htm (http://people.ee.ethz.ch/%7Echapman/il2guide/cemguide/controllingrpm.htm)

And then you can try doing the things I suggested in the above post and see for yourself.

EDIT:ADD
Oh and Prop Governor is the *part* of the systems I was attempting to describe in general.
Curtiss Electric is different from Hamilton Standard is different from Rotol is........

For some obscure reasons, Oleg who is an AE has chosen to make response speeds as they are.
You know the P-39's used Curtiss Electric? That between N and Q models there were control
changes? I don't see that in the sim so what we have is somehow simpler perhaps because of
room in the code or maybe some deep dark reason from the moon. http://forums.ubi.com/images/smilies/bigtears.gif

BfHeFwMe
04-18-2006, 06:35 PM
Not every variable pitch prop system is a CSP. A CSP requires a prop governing mechanical computer by definition.

All I ever did was work on and crew em. http://forums.ubi.com/images/smilies/59.gif

Blood_Splat
06-04-2007, 05:52 PM
When flying the Lagg I'll keep throttle at 40% and PP at 65% to maintain 2100 RPM. It says combat RPM are 2750 but I'll keep it at 2700. It just that when I'm in a fight I'm constantly looking at my RPM so I don't go over 2750.