 Additional munitions and an expanded bombing capacity were a recurring change made in many of the subsequent variants of the Wellington developed during the war, including the carrying of ever-larger bombs.Defensive armaments comprised the forward and tail turret gun positions, along with a retractable revolving ventral turret.Due to the high cruising speeds of the Wellington, it had been realised that fully enclosed turrets, as opposed to semi-enclosed or exposed turrets, would be necessary; the turrets were also power-operated in order to traverse with the speed and manoeuvrability necessary to keep up with the new generations of opposing fighter aircraft.