Since there are a lot of newcomers coming in to CoD I thought it might be useful to give a little overview of CEM, Complex Engine Management, which is one of the most funny and rewarding things this sim has to offer. I actually think that a lot of us who played Il-2 Classic were wishing that the engine management could be a little bit more realistic, to approximate our sim experiences a bit more to those of our WWII fighter heroes. Well, it IS more realistic in CoD, and that is a major part of the fun to be had with this sim. I personally think it strikes a good balance between "giving us more" and not going overboard à la DCS A-10, which is only for the most fanatic of button pushers.
So, the CEM is not VERY hard, but you definitely need to make a little effort.
I'd suggest you start out by setting at least throttle, prop pitch and mixture to your joystick. I personally have the radiators, flaps, landing gear, etc., on easy-to-remember keyboard keys.
Lets first look at the start-up procedure of the early Spit, which is quite simple:
Throttle to idle (i.e. a tiny bit forward from the most backward position)
"i" for ignition
Add a little throttle gradually, up to maybe ten-fifteen percent, but not so much that the engine starts running rough.
Watch temps climb to "nice and warm", i.e. around 60 to 80 degrees (Temp gauges in lower-right corner of dash-board. Speed up time if you're impatient)
Open radiator ("handbrake handle" left of the seat)
Full throttle and take off.
The important bit is that you should hold off on giving too much throttle when you hear and see (vibrations) the engine running rough. Just wait a while and let the coolant and oil heat up and then the engine will run fine, even eventually with full throttle.
After you take off, you can then mess with mixture if you fly high up and with prop pitch if you want to fly faster. However, the early Spit only has two settings for mixture and two for prop pitch, so it isn't as if you need to micro-manage anything. Prop pitch and mixture in the early Spit is for optimizing your performance in flight up high and fast, but let's do baby steps first and just learn to take off, fly around and land again.
Now the Bf-109:
Fuel cock open (big handle with round knob in upper-left corner of the cockpit)
Throttle to idle (a bit off the backwards stop)
"i" for ignition
Wait for temps to go nice and warm, 60-80 degrees. The temp gauges are in the lower middle of the dash-board, behind the tip of the control column).
Open radiator fully
Full throttle and take-off.
Prop pitch is more important for running the Bf-109 engine well than it is for the early Spit. The indicator looks like a clock-face and is on the extreme right of the dash-board. The prop pitch handle is smack in the middle of the dash-board. Interestingly, the handle only shows your input (up for coarse pitch, down for fine) but not the actual prop pitch position, since it springs back to neutral. So, unlike the Spit, the prop pitch handle is not simultaneously a prop pitch indicator: you have to look at the clock-face for that. It actually makes sense that the pilots didn't need to fiddle with a very sensitive handle for an action that could ruin their engine in seconds.
In flight you have to fiddle quite a bit with the prop pitch to fly at anything but slow speed. So, only low pitch for take-off and fast climb. For the rest you need to input a more coarse pitch. Listen to the engine and look at the rpm's. Remember, you're flying for the Führer, so be sharp.
I intend to add more CEM quick and dirty guides for other planes to this first posting, but this should be enough for your first ten hours with the sim. I'm a bit of a knucklehead myself, so I'm sure some errors crept into this first posting. Alert me to them and they will be swiftly fixed!
BTW, if you want to see it, have a look at the movies in my signature.