The reason for the long actuator is due to the amount of movement required at the canopy rail. It slides back 100mm so would need a large horn on a servo which would therefore take up a massive amount of space in the radio bay. Doing it this way, a standard servo and horn does the work in a normal amount of space, leaving the actuator to move the most well out of harms way. The whole set up is completely removable for servicing etc so should never need taking out!!!!

Ian.