I there, I'm new to aircraft editing and I have a question:

Is there any way to have variable angle of thrust?

I'm thinking of the harrier:D

so no way of getting the harrier to hoover

one other quezstion, is it possible to have a jet with usual fight dynamics but copying the flight dynamics part of the engine on a heli and put it in the jet air file changing the the heli engine to a jet one?
I don't know if I make my self clear...

Okay, the changing the engine type question: doesn't work like that.  If you have a heli engine, its a heli.  If you have a jet engine, its a jet.  There can't be a combination of the two, or some sort of switch-off.  The heli in FS is a completely different type of engine than the jet.

As for adding an engine, it can be done in the aircraft.cfg.  Just go find the spot where it says: [GeneralEngineData] and look at the stuff below it.  Its pretty self-explanatory.  To create another engine, copy the last Engine.X and paste the same thing just below the one you just copied (?).

If you want to change the location, that's done with the three numbers to the right of Engine.X, although I can't remember which is which.

That's pretty much it.