Piaggio P.108 - P.108B - Defensive Armament

Defensive Armament

The defensive armament of the first P.108 series consisted of eight Breda-SAFAT machine guns. One Breda "O" 12.7 mm (.5 in) with 450 rounds was fitted in the nose, and a Breda "G9" 12.7 mm (.5 in) in a retractable ventral turret, with 400-450 rpg. In addition to these two fully hydraulically-powered turrets, there were two 7.7 mm (.303 in) guns in the flanks, with 500 rpg. The wing armament, which constituted the main defence of the aircraft, consisted of two radio-controlled, hydraulically-powered Breda "Z" turrets with 600 rpg in the outer-engine wing nacelles, linked to one of the two cupolas in the fuselage "hump", with an operator in each. The wing turrets represented the most innovative aspect of the P.108's technology.

Although considered a very advanced design, the operational suitability of the wing nacelle turret installations was questionable.

• The wing turrets were vulnerable to battle damage, icing and jamming, and were notoriously unreliable owing to the complexity of the sophisticated gun control and computing device (the hydraulic systems had circuits stretching for several metres to the external engine turrets).
• Firepower endurance was adequate for limited combat such as that likely to be encountered during night missions, but insufficient for the needs of extended combat. A total of 300 rounds, fired at full ROF by the Bredas (no synchronizer present, different to fighter installations) was enough for only 25 seconds of use (around 12 two-second bursts). American bombers generally had 500 rounds for each 12.7 mm (.5 in) machine gun and often carried extra ammunition.
• In contrast to the fuselage turrets, there was no possibility of maintaining, reloading or repairing the wing turrets while on a mission.
• The mainly rear-directed field of fire was poor, partially blocked by the tail surfaces, with fire in a frontal arc possible only with high degrees of elevation (avoiding the propellers, again due to the lack of a synchronizer), and no capability against targets below.
• If the wing turrets were disabled, the P.108 was left with only two 12.7 mm (.5 in) and two 7.7 mm (.303 in) machine guns, leaving many blind spots all around the bomber, because none of the flank, nose, or ventral guns' fields of fire covered attacks from the rear or above.