Buckingham 4
In response to the fatal blind spot experienced with the Blenheim under the tail, Bristol designers opted for a bathtub-type gondola that housed the bomb aiming position and a rear Bristol Type 13 under turret, similar to those found on the He 111 and Ju 88 bombers. The gunner’s view was somewhat limited, as the rear section had partial glazing with a rectangular sighting window that could be opened using a Teleflex push/pull flexible cable control system, providing a clear view for aiming the two Browning guns.
The turret was suspended on a top bearing, supporting a U-shaped frame on which the guns and operating mechanism were mounted. The hydraulic rotation ram was positioned at the turret’s top, allowing the guns to turn 60° to each side. However, when fully traversed, aiming became quite challenging. The two 0.303-inch Brownings were mounted on their sides and fed from two fuselage-mounted boxes. The gunner had easy access to the cocking levers and fire and safe units. To operate the guns, the bomb aimer manipulated two handles controlling the hydraulic elevation and rotation valves while lying on a padded rest. Firing the guns was done using triggers on the handles, and the gunner sighted the guns through an inverted G.IIIA reflector sight while placing his forehead on a headrest.
The hydraulic pressure required was supplied by an electrically powered gear-type pump located in the fuselage just above the turret. To enter the gondola, the gunner used a door located at the center bottom. In case of an emergency, he could exit the aircraft through the same route. However, it’s worth noting that the Type 12 mid-upper design allowed for passage through to the front fuselage, providing an alternative escape route.