The energy torpedo was a variant of normal plasma weapons. It was made of fusion plasma which was shot into a magnetic bottle at the target. The magnetic field which contained the plasma could not hold it together more than a minute, but the speed of the energy torpedo allowed it to cover a huge distance in a short time.
An energy torpedo was a kind of missile with an unlimited supply of ammunition. Lacking electronics, these torpedoes could only fly in a straight line and had to be "dumb-fired". The huge weight of the launcher and extended recharge time prevented the energy torpedo from becoming a standard weapon. The recharge time of a light torpedo was 30 seconds, medium ones had a recharge time of 45 seconds and the large energy torpedo launchers needed one minute to recharge. The speed of an energy torpedo was 20% the speed of light in addition to the firing ship's movement in the direction of launch.
Trade federation Vulture droid starfighters were equipped with two energy torpedo launchers.