Originally posted by Rami Sihvo
Still Iwar had small time acceleration effect
when you used main drive, wich was some sort
of hopper drive.
I-War had three different drives. There was the conventional drive (with the Newtonian physics model), the Linear Displacement System (LDS for short) drive, which was the high speed in-system drive, and could move the ship very rapidly. There were no Newtonian physics involved with this drive system. Whichever direction your ship was pointed in was the one it was travelling in, and there was no momentum (made for a great set of brakes when your conventional speed got too high). It also made the ship immune to things such as weapons fire. Finally, there was the Jump Drive, which used LaGrange Points in a manner similar to jump nodes in Wing Commander.
Both of the in-system drives (conventional and LDS) worked best with computer assistance. The conventional drive used the computer to balance out thrust and reaction, so that you didn't need to worry about moving one way after you'd thrusted another (it would also keep your speed down). Since the LDS drive was capable of extremely high speeds, and was typically used to transit to a specific location or for pursuit, the autopilot was typically engaged while using it.
In both cases, the computer could be deactivated/left off if you so desired (for example, to take advantage of the ability to strafe in combat). You could always leave the computer on while using the conventional drive, but a skilled pilot could do some pretty amazing stuff with it off.
Having the computer was probably one of the best ideas for the game. That way, when your momentum vector got a little too wild, you could turn on the computer assist, get straightened out, and then turn it back off again.
Incidentally, I would venture a guess that the fact that the drive system is abbreviated LDS, and that the orbital station you spend a lot of time visiting is called Salt Lake City, is NOT a coincidence.