So, I read what I could find for help, but I still pretty much have no clue as to how you get the bo105 off the ground.
I started the rotors, throttled all the way up, played with the "i" ignition button (although it didn't seem to be required, as the "}" key starts the rotors... ?), played with middle mouse button to increase general power although it didn't seem to respond on my system in a predictable way (I occasionally got a message telling me the new power setting, but at irregular intervals), and played with n/N for more engine power, with nothing resulting in enough engine torque to lift the machine into the air. Once or twice through joystick movements and/or throttling back to 50% (which seemed to increase the noise of the engine, not sure if this means more power or not) I actually got it airborne enough to throw itself into the ground, but clearly I need more help than the list of control keys.