Hi, and welcome!
There are a few threads in some forums to get started with the game, I'd recommend this one:
http://forums.ubi.com/eve/forums/a/t...3/m/9121094645
and also this
http://forums.ubi.com/eve/forums/a/t...3/m/4551011977
these pretty much contain everything you need for starters!
To answer your questions shortly:
1) Check the first link
2) As far as I know, in game it doesn't do anything at all, no apparent power increase.
3) Again, not 100% sure but this seems to lower fuel consumption, and also gives less power on really low settings (0 to 40). You also need to lower the mix on some planes as you go higher. This is because the carburettor "chokes" from too rich mixture, as there is less air up high.
4) Radiator or cowl flaps are used to cool the engine so that it doesn't overheat. In radial engines, the flaps opening on the cowling let air pass around the cylinders freely, and thus to cool them. In liquid-cooled engines, it opens flaps on the back of the radiator, and this cools the liquid used to cool the engine.
If you get the overheat message after a while by using high power setting, you can open the radiator (and reduce power) to cool it back to normal.
5) Elevators are usually the control devices on horizontal stabilisers, used to control the pitch (up/down movement) of the aircraft.
Respectively, there are ailerons on wings near the tips, controlling roll (movement around longitudal axis), and rudder for yaw control.
6) 100% propeller pitch means that the propeller blades are set at such angle at which they grab the least amount of air and thus produce less thrust. However, for most planes this allows the engine to run near it's optimal rpm range, and usually it is the fastest setting. By lowering the pitch the thrust per rpm increases, and this is recommended for cruise flight.
Some planes have
constant speed propeller(CSP), which, as you control the blade pitch, keeps the engine running at constant speed. Some have just a normal manual pitch, some are fully automatic, and some older ones have only two settings or a simple, fixed, unadjustable propeller.
A common misconception is that the pitch setting changes the drive ratio between engine and prop. This is not true, and such mechanism would be nearly impossible to build.
7) I haven't played any of the offline campaings for a while now, but I'm sure someone else has the answer already...
8 ) Superchargers... not that abstract at all, pretty simple in fact. It is a device used to feed more air into engine cylinders by
supercharging,
forced induction or most commonly,
boosting. The pressure increase is usually called
boost level.
It comes in different varieties, the simplest one is a single
compressor (in aircraft usually
centrifugal) geared from the engine crankshaft, and as the air flows through it, it's pressure is increased.
Many WWII aircraft had
two speed superchargers. This means that there were two different gearings to it, low gear used on low altitude (preventing overboost), and high gear on high altitude (giving more power as the boost pressure starts to drop on low gear at certain altitude).
In addition to two (or even three) speeds, there were
two stage superchargers. From this you don't have to worry at all, it's basicly two centrifugal compressor behind each other, each running at their optimal speed. Result = more boost, more power (especially in higher altitudes).
Another common misconception is that, if in game, a plane doesn't have an adjustable supercharger, it doesn't have supercharger at all. Of course, this is not true either, nearly all combat aircraft flown in WWII had some kind of supercharger. In such case, the supercharger is either single-speed, multi-speed but automatic, or even an automatic
turbocharger+supercharger configuration.
If you are confused about some of the terms (in italic font), wikipedia and google provide lots of detailed information to make you even more confused.
Hope all this helps!
Edit: 3 posts were posted in the time I wrote this, but anyway...