CEM prop pitch discussion on UBI GD forum

[TX-Zen]

Gentlemen,

Take a look at this thread in the GD:

http://forums.ubi.com/messages/message_view-topic.asp?name=us_il2sturmovik_gd&id=zjlih

The first part explains how the prop pitch works in real life and how it relates to FB. (Eco jump in here and correct if you see something out of wack)

The middle part mentions that VVS planes do not seem to overspeed or over-rev their props and that the luftwaffe planes do not get maximum performance on auto pitch due to a possible FM bug. Manual prop pitch control is mentioned as the way to get the most out of the luftwaffe (with the understanding that this is opposite to real life).

I was also talking with Raptor the other day who gave some examples of using manual prop pitch and engine power settings to acheive higher performance levels.

I'd have to say that based on the thread, some observations of my own and what Raptor mentioned, that it may be a good idea for the squad members who regularly fly luftwaffe planes to take a good long look at using manual pitch control. I bet we can convince Eco to give his private lessons and I'm sure Raptor will be happy to share his experience.


Anyways, take a look at the thread, its an interesting read. I can't say that I've run into situations where I was shot down for lack of manual pitch control, but I've been in a couple where I was begging for just a tad more power to get guns on target and sometimes those moments make or break you in those hot dogfights. Be nice to have one more edge over the opposition.

Something to think about in any case.

TX-Zen
Black 6
TX Squadron CO

[TX-EcoDragon]

I still say what I said two training sessions ago. . that we just get our booty in the plane, and go do some hands on CEM work while on the voice comms. . . I guess if we still are posting about it we still dont understand it, so lets ask questions about what we dont understand, but lets do it on GV, and with 1,500 HP under our arse!!unless you are looking at the tach (should be manifold pressure. . but oh well) while you make these changes you will not be able to understand. . .so reading this that and the other thing aint gonna help in my mind, untill you just fly it. Not all planes in this sim NEED you deal with teh pitch, meaning they dont burn up the engine in 10 seconds. . but you should learn to manage the prop anyway. . and manage it for all planes you fly. . .one thing I have to say though, is flying with no cockpit will make proper CEM impossible. . .so just keep that in mind.( I still say leave auto running in 109s while in df, unless in low speed vertical situation. .. otherwise run it full manual, and keep on top of it)my .02

[TX-Raptor]

Manual prop pitch is not as confusing and complicated as many think it isand I think Eco probably put it in the best terms I've ever heard, and that was in comparison to an Auto transmition that was you wasnt it Eco? hehe  anyway Ever heard stunt planes or crop dusters pull out of a dive, even a shallow dive? recall the BEEEEEWWOOOOOOOOWWWWW  sound you heard?well thats just the prop changing position and digging into the air, think of it as downshifting etc etc.     I would recommend that you take your favorite ride up into the sky and experiment with it, and make sure you write down your airspeed and prop pitch and mixture setting you will be able to establish a table if information and gather your best performance data, and then you will "KNOW" how to milk the most from your Plane. Question for Eco:   Eco it's been a long time since i've flown a variable pitch aircraft and my memory is a bit fuzzy on this, but it seems FB is backwards because when you reduce pitch your engine sounds like the RPM's drop  which I was always under the impression it increases drastically therefore the easy overheats and blown engines, am I wrong here?

[TX-EcoDragon]

The basic objectives of the prop pitch control, is to allow the engine to operate at its ideal power setting, for any given speed through the air, be that 140 kmh or 700 kmh. the way you use this control is simply this: look at the notes I posted in the CEM thread for the particular aircraft you fly, set throttle to desired setting (usually 80-100%) and then use the prop control to keep rpms at the optimum range, which is the max allowed RPM, when in combat.So I will describe a basic flight in a FW190 D9 using the info from my earlier post.D9 power settingsTakeoff Speed:170Landing Speed:155Combat Engine Setting:3000Best Cruise:2600Economy Cruise:2500Start engine at 100% prop, use lower rpms while in this configuration. When ready to begin takeoff roll, begin advancing the power towards the takeoff  power setting of 2,700-3,000 RPM. If you leave prop set at 100% you will easily exceed this RPM range as you add more power. You must adjust prop control to a lower number to advance the power any more, and as the aircraft accelerates. That 3,000 is your upper limit, that is your ultimate  guide as to prop pitch settings. Ideally you want to run at maximum power (so 100%) and 3,000 RPM (or a little less if able). So advance power, and pull back the prop just enough to stay in range. Once you have gotten wheels up and a little speed, lower the RPM to a more reasonable setting of 2,600. See, the throttle is not the PRIMARY way you control engine speed now! the throttle can be stuck at 100% and you can change your tachometer setting. . .from a takeoff setting of 3,000 to a climb setting of 2,750, to a cruise setting of 2,600. . .all without touching the throttle.Lets say you want to dive now. . . before diving either lower power setting, or lower prop pitch, practice offline a bit to see how much you need to pull the prop back for a given speed and power setting. . .there is no other way to do it other than practice this. You may realize that the auto pitch settings do not give great performance, that is because they limit the engine to a non combat setting of 2,600 RPM. This is fine for cruising around, but the engine lugs at this setting, and a pilot with CEM on his good side will fare far better than a pilot simply on auto. BUT!!!!!! it takes practice to be able to df and deal witht he prop. . .and way more practice to do it with cockpit off. One jab of the prop to 100% while you are at max throttle setting and your engine will go bye bye very fast. . so use caution, and use the auto feature online if you need to. . but start working without it, and it will come to you.Raptor, I think the issue that you are having is a matter of nomenclature, but I may be wrong.  I think of the values FB gives as a percentage of Possible RPM. .. so 100%=unrestricted, 90%=10%respricted etc. .. does this mean that at 50% prop pitch in a D9 should give us about 1,600 RPM at max power whne on the ground. . . im not sure. . but im gonna go seeFB is simplified, and you dont have to worry about pulling too much pitch for a given power setting and airspeed as much, you simply need to prevent the engine from over reving. . .by restricting their RPM to the operational limitations.S!TX-EcoDragonCurrent mount: P-39 Q10Favorite Plane: BF109-G6A/Sand a bandit on my 6Most feared/resented FB addition: LA-7Characteristic noise during dive as reported by a third party witness: GGGGRRRRRRRBBBBBRRRRAAAAAAAAAAAAAAAAAAAAAAAAWWWWWWWK!!!

[TX-Chukar]

I was hoping for an advantage in learning to using the prop pitch correctly, especially over VVS aircraft.  What I found was that using prop pitch in German planes is a must, whether auto or manual (manual is better).  For instance in the 109, traveling at 400 kh with PP in manual mode I could climb about 150 to 200 m higher than when I was running in auto PP.  The reason is that the auto PP is governed too a lower rpm.   In manual mode I could easily keep the rpm’s between 2600 and 2900, in auto it was lower and it could really depended on what you were doing before the climb started.  You can watch this by checking out your rpm and prop pitch gauges.  Notice that when you change the pp manually the pp gauge (marked HB) moves immediately and in auto it just slowly trucks around the dial while maintaining a lower rpm rate.  If you not sure of how it works think of like this, it’s very similar driving a big truck.   100% is like first gear and lowering your percentage is like a higher gear.  Say you’re cruising along in a higher gear at (65%) and 2200 rpm.  You decide to climb and you pull back on the stick, right away your RPM’s start to drop.  You will need to up shift to a lower gear (lets say we jump two to get our RPM’s up to max at 2900) and now we are at 75% and the engine is pulling hard.  As the RPM’S drop to 2600 we can down shift again to keep the engine in the power band.  When your reach 100% that’s it, there ain’t no more so ride it for as long as you can.  Now if your roll over and point your nose straight down, it’s just the opposite, start up shifting fast or you will over rev and seize the engine.  See it’s just like truck driving, down shift when climbing and up shift when going fast or downhill while trying to keep your rpm’s in the power band..On the other hand I tried the Yak 3 and the La7 and yep they're the uber plane.  They have manual pitch and no auto pitch but in FB they don’t need it (is this modeled correctly – I don’t know).  Set it for 100% and leave it, you can still out climb all the German planes and never worry about over revving.  Even in a dive you can’t over rev it. Eco suggested that there should be an optimum rpm or manifold pressure range for each type of engine to maintain max power and temp control.   If you compare them to car motors my impression is that the Germans fly with small block Chevy’s (pulls best at a higher rpm) while the Russians use the big blocks (good low end torque at low to medium rpms).TX-formerbigrigdrivenstreetracing-ChukarBlue 1

[TX-Deck]

So.... essentially if you are using a throttle controller, map the actual power to some Up/Down button of sorts, and then the throttle slider could be used for prop pitch?Seems like this would be an efficient way to keep a grasp on the situation.Thoughts?TX-Deck out."I started out with nothing, and still have most of it left."

[TX-EcoDragon]

well, in theory that would work. . and maybe even work well for a hotas user. . .but I for one think that is taking it a little too far. . I simply have my most accesible rotary mapped to the prop pitch.S!TX-EcoDragonCurrent mount: P-39 Q10Favorite Plane: BF109-G6A/Sand a bandit on my 6Most feared/resented FB addition: LA-7Characteristic noise during dive as reported by a third party witness: GGGGRRRRRRRBBBBBRRRRAAAAAAAAAAAAAAAAAAAAAAAAWWWWWWWK!!!

[TX-EcoDragon]

yes chukar. . that last point you made is  a good one. . .but i'd say the german planes are more like an Integra VTEC  ;-)Current mount: P-39 Q10Favorite Plane: BF109-G6A/Sand a bandit on my 6Most feared/resented FB addition: LA-7Characteristic noise during dive as reported by a third party witness: GGGGRRRRRRRBBBBBRRRRAAAAAAAAAAAAAAAAAAAAAAAAWWWWWWWK!!!

[TX-Deck]

After a bit of fiddling, I was able to readjust the bindings on my Hotas and test out the prop pitch settings.The single most thing that throws me off, is cruising at 100% power, hitting what seems to be a top speed with prop pitch at 100%, then lower the prop pitch to somewhere between 70-80% and have the engine lower in rpm, yet airspeed increases.   Truly like shifting gears in a car.TX-Deck out."I started out with nothing, and still have most of it left."

[TX-EcoDragon]

Yes deck, that is the heart of it. . .technically a constant speed prop should be lower workload, as the prop governor should maintina the RPM that you dailed it to. .. but the sim seems to only really model variable pitch, but not constant speed.Auto pitch in the 109 and 190s is similar what you should see even when in manual in those planes. . . except that you select the RPM with the PP control isntead of it chosing. oh well. . I expect there to be many changes to this system in the upcoming patches.