Optimizing flight/speed with CEM

[prophet106]

Hello all. Another newbie here . . .

I took the plunge a couple of days ago and decided to start playing the sim properly with CEM turned on. I'm looking for a few pointers with regards to optimizing my flight. I've done lots of reading (especially here - http://www.2gvsap.org/flea/OP2GvSAPINST_3710.1A.pdf) and watched a fair few vids on youtube for pointers. Of course a have a couple of questions :)

Firstly my start-up/take-off procedure with the MKI spit looks like this (keeping in mind i'm new to this game)

- Fuel on
- Megnetos on
- Airscrew fully fine
- Mixture rich
- flaps normal
- Start engine

Wait for a little while for her to warm up

- Full throttle and adjust for swing/torque
- Tail up (50ish MPH). Nose up (100ish MPH)
- Wheels up
- throttle back to about 80%
- Rate 1/2 climb

This is when the problems start

Firstly my exhausts smoke a little. I assumed it was the rich mixture so i set it to weak (with my current controls mixture is either 'yes' or 'no'). Still smoking. Interestingly enough if i switch to auto-pilot the smoking immediately stops and performance improves. What the hell is 'he' doing that i'm missing ?

Next is with regards to prop pitch. I was under the impression that once we are in general flight we should switch to course pitch. When i do the oil temp and revs drop but so does the speed. Anything more than a rate 1 climb and you are loosing speed. Trying to catch up to a bomber formation above is a right ball-ache (without blowing the engine by flogging it to death)

So smoking exhausts (viewed with cockpit off, until my trackir gets here !) and lacking power. Any hints/tips would be greatly appreciated

Many thanks
James

[Bulau]

Well, I've read that there is a mixture bug that affects the Hurricanes, perhaps also the Spits, wherein the mixture control is bass-ackwards. So you might try setting mixture to RICH and see if that actually gets you LEAN.

My understanding of coarse pitch is that it's for cruising economy. If you're trying to catch up, use fine pitch.

[whoarmongar]

Congrats on tackling CEM it can be daunting at first but is probably the most satisfying aspect of this sim.

For a self confessed newbie you seem to be doing fine and have the basics sorted.

The Mk1 isnt easy to fly becouse of that horrible prop, the frustration you have with the Spits Mk1 performance is shared by all. However if you want to fly a spit online your stuck with the Mk1 and Mk1a coz most servers dont allow the MkII due to its performance advantages. Its due to this that many online RAF fliers now use the Rotol Hurricane just to get the more efficient prop/engine management and better rate of climb.

If you do use the Spit I am by no means an expert but I can pass on a few ideas that I have found to work for me

Flaps are only used for landing with the spit not for takeoff

Warm your engine before taking off this is essential

Set your compass and course setter whilst waiting for your engines to warm, its very easy to get lost on a realistic setting server with no map help.

In theory its rich mix for takeoff and lean at height and for cruising, but its a bit bugged and seems to change with various patches to be honest i havnt got a clue what is rich and what is lean anymore I just use whatever the engine seems to prefer, its certainly less critical than it was before all the patches so just experiment, its a bit like setting a carb up in real life, if the revs pick up the engine likes that mix, if it coughs splutters or farts it dont.
Open your cockpit canopy for better view.

Open your Rad for takeoff, but once up and flying close it to 50% ish and just watch your temps and open and close accordingly.

After takeoff Dont try to climb immediatly, set course pitch stay low and get some speed up, the engine revs will drop, but you will eventually go faster. You will find that with coursepitch in level flight you will only get anywhere near max revs @ about 16000 ft, this is due to air density. Its very easy to over rev in a dive, so coursepitch throttle back.

If your engine starts to "bog down" and you cant get any revs switch to fine pitch and climb a bit or keep in course pitch and dive a bit, obviously not at low alttitude

Really the only way you will blow your engine is by overeving it 2850 is my max revs for safety, or overheating it so watch your temps, to be honest I have never killed an engine by overboosting it but then again i have never "gone thru the gate"

If you have to climb hard, set fine pitch and rev that engine, For some reason I find it better to climb in "steps" rather than a constant climb, I dont know if this is real or just my perception but it seems to work for me, so I climb hard fine pitch, level out coursepitch, pick some speed up then climb hard again and this for me works when chasing high bombers, it also avoids arriving at the bombers from below whilst climbing
slowly in full view of them rear gunners, instead I do a final claw for height behind them then attack at speed then after the attack convert that speed back into height ready for another go.

The rotol is so much easier to use, basics are you set your throttle and use your prop pitch to keep the engine in the sweet spot, after that horrible prop in the Mk1 its a total joy to use.

hope this helps

BTW im a terrible pilot and even worse shot, in truth I prefer bombers (lets not go there with Clod) so I just play with fighters to give others some target practice, im just happy to survive a mission.

Have fun

In time this is going to be a great game

If it can just survive its difficult birth.

[Vengeanze]

Guess you opened up radiators. Otherwise that will overheat your engine and break it a couple of minutes after take off.

Otherwise your to procedure looks ok.
You could add like 20 clicks on nosedown trim to get your aft up faster.


Edit: Actually no need to switch on Magnetos in CloD. Just the fuel cock and 15% throttle and hit I. After that u can run through the check list while the engine warms up.

[prophet106]

Thanks for the replies chaps (and that lengthy one Woarmonger, excellent).

Yes i open the radiator fully for take off/landing and keep it at about halfway during flight. i'm still slightly at a loss as to the exhaust though. i haven't even contemplated playing it online yet. just working my way through the campaign (hence having to use the spit). i'll try doing as you say with regards to keeping low after takeoff and building up airspeed before climbing.

yes the first couple times i took off for an interecption i keep climbing in fine pitch on full power. It either pops the piston head or blows the carb.

Thanks again. more innane questions to follow im sure !

[Blackdog_kt]

Whoarmonger got most of it and you seem to have a good grasp on things, so i'll only add two things:

Mixture: Not all people agree it's a bug, because it was reversed in the real aircraft too. This is a carry-over from manual mixture systems, so that by pulling the throttle back the detent on the throttle lever will also pull the mixture back into rich to prevent fuel starvation.

Try to think in terms of what you see the controls doing in the cockpit and not what your key bindings are titled and you'll be fine: auto-rich mixture is with the lever fully back and auto-lean with the lever fully forward.

Prop pitch: Think of it like gears in a car. The two-stage prop only gives you two gears (fine and coarse pitch) so it's like you only have 1st and 4th gear, but they do have a pretty wide power band. In fact i find these Spits pretty easy to manage compared to a 109 which has fully adjustable but still manual pitch.

Use fine pitch just like you would use 1st gear in your car: Slow climbs, low speeds, to limit your speed in a dive (just throttle back a bit to avoid over-revving it), when you want faster response to throttle changes (both decrease and increase) like for example when taking off/landing. It's good to have it on fine for the landing approach in case you need to go around too.

Use fine pitch like a 4th gear: Fuel economy during cruise, attaining your top speed, accelerating in the dive and climbing while at high speed (switching to fine for every climb is like driving on the highway at 140km/h and downshifting to 2nd gear whenever you see a small upwards slope on the road: the torque sure is enough to climb it, but you are bleeding off speed like crazy).

Keep in mind that changing the pitch will also affect manifold pressure, even more so with these props because the pitch change and resulting torque change is quite big: boost will rise when setting coarse pitch so you might need to throttle back a bit, in a similar fashion it will drop when going to fine pitch and you might need to throttle up a bit.

As you can see, it's mostly situational and there's not a hard and fast rule. In fact, there are cases when flying at fine pitch all the time severely limits your performance, like for example trying to catch a 109 in a dive: fine pitch will not only cause the RPMs to pick up and force you to throttle back, it also gets to a point during the dive that the prop creates considerable drag, due to the prop blades being almost face-on to the incoming airflow. It's like having a disc-shaped airbrake in front of you.

Switching to coarse pitch in such a case presents a smaller "head-on" cross section of prop blades in regards to oncoming airflow and lets you pick up more speed.

[EZ1]

You may want to keep that radiator open a bit more in flight--85% maybe. I just closed mine to 50% and it blew a gasket in about a minute. LOOK at the temp guage.

[prophet106]

Thanks again for the tips chaps, invaluble

EZ1 i normally fly with my rad about 70% closed, it seems fine at that setting ? Temperature normally sits at around 100

I do have another question with regards to airspeed; Just flown the mission on campaign where you fly as #2 to the wing-co to take photos of the jerry airfield near calais. You both fly at low level all the way to the French coast. Now if i am flying manually he slowly draws away from me. If i switch to autopilot he manages to catch up again. What am i doing wrong ? I have -

- Airscrew in coarse pitch
- Rad about 70% closed (temp sitting comfortably on about 100 IIRC)
- Fuel rich (assuming it's rich, if i switch it back the other way it slows down)
- Elevators trimmed so it's almost flying level (apart from the torque which needs a bit of left aerlieon)
- Throttle pretty much at 100%

When the autopilot takes over no levers change position ? However those exhaust traces do disappear. Next time somebody is flying a spit would they mind quickly switching the cockpit off and seeing if they still get the slight smoke from the exhaust ?

Thanks again

NB - Bagged two 109's and a 110 yesterday for the first time flying with CEM. Nice feeling

[touchdown42]

Just an idea, perhaps you've trimmed nose heavy and the smoke comes from neg G carb overflow.

What if you pull the Spit into a slight climb? Still black smoke then?

[Vengeanze]

What color is the smoke? White/gray then it's a waterleak from overheating.
Check the gauge to the right that says water temp (or something). Max is 120 (90 for oil temp).
Throttle down a bit after TO when you're >120mph

[prophet106]

It's thin white puffs. Not smoke per-se (there's no trail behind the aircraft). I get it from the moment i take-off to the moment i land so it can't be overheating. I normally fly with water temp at about 90-100. It's annoying knowing i can squeeze more speed from my crate but don't know how

Perhaps i can find out how to video it and upload/post it ?

[Blackdog_kt]

Try going to an external view (enable them in your difficulty settings if you need to) and making an attempt to identify the point from where the puffs originate.

I haven't spent much time in the RAF fighters except for some Hurricane sorties, but if you could tell us where the puffs of smoke appear on the airframe we might be able to give you a few more hints.

The effect you describe however is similar to a busted radiator: if you let the temps rise too much the pressure in the lines gets higher as well and it can break the pipes. When that happens, you can see white/grey puffs of steam coming out of the radiator.

Another thing which i'm not sure if its modeled in the sim is the escape valve. In the real world Spitfire there was an escape valve ahead and to the right of the windscreen, when the coolant would overheat some of it would be blown out of that valve to lessen the pressure and prevent damage to the pipes. This allowed pilots to "ride the overheat" so to speak for a small amount of time, at the expense of depleting their available coolant supply.

[Jatta Raso]

i got the hang of it like this:

take off:
fine pitch
radiator 50-70% (what takes not to reach 100ºC)
engine 20%
->fire engine
warm up (do your check list in the meantime)
->engine to 30-40% (start moving, watch the temps and adjust rads accordingly)
->if no engine stuttering: step on it

airborne
using your throttle (but not bellow 80%) and climb angle to keep the revs bellow 2800rpm, start a shallow climb until 1000m; go in steps if you have to; always trim to get just your intended angle; don't wait for the stall to interrupt the climb, anticipate that

once at 1000m trim for level flight, attain your max speed (by now i close my rad about to 70-80%, always watching)

climb to 2000m using same process

once at 2000m trim for level flight, attain your max speed

start a shallow dive and change to coarse; your revs should jump to near 2100rpm
->throttle to max; use the small speed gain of the dive to help the spinner pick up revs
once at 1600m you should have at least near 2300rpm which is by now a stable engine operation, that allows for an efficient rev pick up; at coarse pitch you must not fall bellow 2100rpm or you may need to go back to fine pitch

start a gentle climb as you should have enough speed for such
climb to 3000m
once at 3000m trim for level flight, attain your max speed; you should be hitting the 2500rpm soon which is the optimal situation you're seeking

if serious trouble persists, maybe i can drop a vid of it...

[pwgee]

Here are my thoughts

Firstly, I understand that this sim is far from flawless.

Secondly, this post is coming from a professional aviator with 20+ years of experience.

If things were modeled and coded as they should be I can tell you that this is the way the sim should operate.

For startup:
Fuel cock on (obviously)
Magnetos ned to be both on, 1+2, the magnetos give the engine the fire it needs to combust the gas and air, these old planes did not have spark plugs. The magnetos keep the engine burning the combustible properly.

Mixture should be full rich, at sea level or close to there anyway, since we are not taking off from a field elevation of 5000ft there is no reason to lean the mixture until we climb to altitude, again I dont think this is modeled correctly in game; I have treid leaning the mixture at 3000m to try and get better performance, but it doesnt seem to do s@$% until u lean it off to the cut-out point.

The prop should be full forward or full fine, it doesnt really matter since the engine is just at idle power anyway. It really wont change prop RPM until you add mucho power (i.e. when u dive in a 109 or 110 u notice you have to pull the props back to avoid over-revving).

Radiators for start should be full open since you are not flying through the air generating any ram air flow to cool them. It doesnt matter too much until the oil warms up to take off temperature anyway.

Crack the throttle and hit the starter.


Climb:

For a real world climb you should climb at max prop for maximum thrust and best climb rate. Watch your oil and water temps and level out for a few minutes to cool them down if you have to. Leveling out SHOULD cool them down as you have more airflow going over the cooling fins.

Manifold/Boost pressure, climb at max until cruise or until you are limited by coolant temperatures.

Cruise:

pull the props back a bit to stay out of the red zone on the RPM gauges, you will hear the prop chage speeds especially in the 110's.

pull the Manifold/boost gauges back to saty out of the red zones.

Just watch your temperatures, close or open the radiators to keep a mid range temp.

Combat:

Full props and full throttle, radiators wide open. The only difference is the 109's and 110's. These props are fully manual and you will burn out the engines in less than a minute if you dont constantly change the prop pitch in dives and you will get crappy climb performance if you dont climb at full fine prop pitch. There is a relationship between aircraft speed and prop speed. You will notice that you cant develop maximum PROPELLER rpm until the airplane is flying fast enough to allow it ( as at roation from the runway), You will also notice that if you are flying too fast for your selected prop setting that you will over rev the prop ( as in a dive).

Basically you can run the props at full fine the entire flight as long as you dont go too fast, this is why we have a controllable propeller.

Also note this, the Spits and Hurris have Carburetters and are not fuel injected as the german planes are, what this means is that if you perfrom ANY negative G maneuver you will get an engine that struggles to stay alive, this may be the white or black smoke that you see, depending on altitude; IF the game is modeled correctly.

Another thing that is pretty cool in this game that I have seen is when you are in a Spit or a Hurri and you make a rapid throttle change you will see a puff of black smoke from the stacks; the carburettors have to deal with the rapid fuel input or rapid fuel starvation and you get mass burnoff of fuel or mass burnoff of air, pretty cool. The rest of the engine modeling could use some work.

The game is really good and have every confidence that it will get better with time just like the first days of IL2 2001.

Hope this helps

[aus3620]

Some excellent advice here. Mainly fly the Hurri at the moment. When I started CEM my flight would often leave me miles behind! I found the key is not to climb immediately after take-off but to build up speed, then climb out. Keep an eye on your speed when climbing and don't let it get below 150mph.

After leveling out go-to fine pitch. I find on fine pitch the engine seems to prefer full-rich, when I lean out it does not run as well.

CEM is the way to go.

Good luck with it,

[whoarmongar]

Ahem...


"Magnetos ned to be both on, 1+2, the magnetos give the engine the fire it needs to combust the gas and air, these old planes did not have spark plugs. The magnetos keep the engine burning the combustible properly."

They most certainly do have spark plugs, "clearing the plugs" was regularly done before engine shutdown on many aircraft.

Magnetos are used to generate current.

[pwgee]

I stand corrected, thank you whoarmongar. Yes the mags were/are for generating the electricity for the spark plugs.