Boulton and Paul P.25 Bugle

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Contents

Type Description

• P.25 Bugle I
• (First two prototypes only) Three seat, three bay biplane medium bomber to Specification 30/22. The structural elements of the Bugle were primarily composed of Boulton and Paul's locked joint system of steel tube construction, with some portions being corrugated for additional strength, while the exterior had a fabric covering. The wings featured horn balanced ailerons on all mainplanes which wereactuated via struts rather than cables. The interplane strut design used a combination of steel inner struts and duralumin outer ones, while the removable fairings were made of wood. Fuel was accommodated within semi-circular tanks hung beneath the upper wing's inner bay area. The fuselage was rectangular in shape, its frame formed from four longerons and built in two sections. Their was a single dorsal gun location, fitted with a single .303 Lewis gun on a Scarff ring mount, to the rear of which the fuselage tapered inwards in a triangular fashion as to maximise the gunner's downwards field of fire. The position of the gunners were deliberately lower than that of the pilot's cockpit, giving the latter a favourable level of visibility. The aircraft's nose gunner, also provided with with a single .303 Lewis gun, acted also as the bomb-aimer, and was provided with separate rudder controls to the pilot to make minor adjustments during bombing runs; all of the bombs were stored externally on four bomb rails, two attached to the lower longerons and two fitted underneath the lower wings. The undercarriage and tailskid both were furnished with oleo-pneumatic shock absorbers, while main wheels akin to that of the Bourges were fitted. Additional dampening was provided via a pair of tubes fitted with coil springs attached to the main landing gear. The tailplane, fin and rudder were all square tipped, with the rudder having a horn balance and equipped with a locking device as to better handle asymmetric flight conditions, such as single-engine operations. Two 400 h.p. Bristol Jupiter II/III powerplants, housed within streamlined nacelles that had a patented hinged mounting, which was designed so that the engines could be swung out of situ while on the ground for ease of maintenance.
  From the third aircraft on, the aircraft differed in having a four-seat configuration, a slightly reduced wingspan, with the aileron horn balance now being inset rather than past the wingtip, and increased fuel capacity. Two 435 h.p. Bristol Jupiter IV powerplants.

• P.25A Bugle II
• Four seat biplane medium bomber to Specification 15/25. As P.25 with Two 450 h.p. Napier Lion powerplants mounted on the lower wings and the fuel tanks moved from the upper wings to reduce drag.

Production Details

Production References

1. Boulton Paul Aircraft Since 1915, Alec Brew (Putnam, 1993)
2. British Bomber Since 1914, Francis K. Mason (Putnam, 1994)
3. Royal Air Force Aircraft J1 - J9999, RAF Aircraft Register Series (Air-Britain Publications, 1987)