So I just get a motor and attatch it to a sisscor jack?
Sort of. Rather than using the whole scissor jack, I just used the threaded rod that goes through the middle of it, and a small nut from one end. The rest of the jack was just discarded. You could just attach a motor to the scissor jack and use the whole mechanism but it would be quite bulky for a featherweight and the shape and size of it would probably dictate your robot's design to you.

Another question how long does take to fully unwind?
Depends on the speed of the motor, whether it's overvolted, what your leverage ratio is etc etc. But for Kaizer, full travel from up to down takes 1.5 seconds max at full speed. I use a speed controller with it though, so can make it go up and down at whatever speed is best for the situation. The nut only travels about 2-3 inches along the threaded rod for full lift so it's possible to get the mechanism quite small.

If you were using the whole scissor jack mechanism then you could be looking at around 10 seconds (just a guesstimate) for full travel.