Lewis gun
The F.2B often carried a second Lewis gun on the rear cockpit mounting, although observers found the weight of the twin Lewis gun mounting difficult to handle in the high altitudes at which combat increasingly took place in the last year of the war, many preferring one gun. Attempts were made to add a forward-firing Lewis gun on a Foster mounting or similar on the upper wing either instead of (or with) the Vickers gun. Among other problems this caused interference with the pilot's compass, which was mounted on the trailing edge of the upper wing: to minimise this effect the Lewis gun was offset to starboard.