Foster mounting

The twin Vickers guns were replaced with two Lewis guns firing forward over the top wing on Foster mountings.

Twin Foster mountings were occasionally used, although the recoil and vibration of two Lewis guns firing simultaneously was considered a dangerous strain for the lightly braced centre section of the aircraft of the time.

The armament was two Lewis mounted on twin Foster mountings in preference to the synchronized Vickers preferred for day fighting located at the upper center-section or fixed to fire upwards in a position that prevented the pilot from losing his "night vision" when the guns fired.