Supermarine (Pemberton-Billing) P.B.31E

Supermarine (Pemberton-Billing) P.B. 31E History

The company existed under the Pemberton-Billing brand before becoming the famous "Super Ocean" company of World War II. One of the company's earliest original projects was the 1915 P.B. 23E propellant biplane. In December 1916, the company officially changed its name to the better-known Supermarine brand, with its first titled "P. eg 31E". The P.B.

31E was based on the earlier, eventually abandoned P.B. 29E "Nighthawk", a twin-engine four-deck interceptor, but had little, if any, impact on the British war effort.

The original P.B.29E was designed as a zeppelin/airship fighter and was designed around the long-range/long-endurance concept, primarily for low-light operations. A full set of quad-wing main aircraft was introduced to provide the necessary lift, drag and artillery platform maneuverability.

The three crew members were carried into the third group to handle a 7.7mm machine gun in the central part of the hull. The gigantic plane was a spectacle at the time, with its stacked main plane soaring through the sky.

The aircraft was completed and flown in late 1915-early 1916, but was eventually lost in an accident during testing. Nonetheless, the concept was interesting to the British authorities, so another version of the aircraft was further developed - this is the P.B. 31E.

P.B. 31E was completed in February 1917, and the first test flight took place in the same month. It basically retains the form and function that will astound observers interested in P.B. 29E. The triple mid cabin quad wing configuration played a role in the design and was very forward amidships.

The outside of the wing has a protruding reverse crank - basically representing an early form of the swept wing. The hull is slab-like and deep, while providing enclosed crew work areas (some of which are heated).

The empennage is a complex structure based on the two-blade, two-plane approach common in World War I bomber design.

From the outset, P.B. 31E required the range and waiting time of P.B. 29E, as the aircraft had to be in British airspace before the German airship arrived.

From there, aircraft needed the firepower and performance to shoot down these fragile airships before they could scout their modest war loads or drop them on British civilians or targets of opportunity. Engineers estimate their new design has an endurance window of about 18 hours of flight time, a very optimistic proposition.

For performance, the design team chose a pair of Anzani 9-cylinder air-cooled radial piston engines, each producing 100 horsepower and driving the multi-blade propeller unit in a typical puller fashion.

The proposed weapon is centered on a 37mm Davis gun (detailed in the small arms section of this site) (here also includes a searchlight powered by a generator), drawn from 20 projectiles. This was supported by a trainable 7.7mm machine gun behind the Davis emplacement and a second 7.7mm machine gun also behind the upper wing.

All in all, this provides the crew with an impressive range of firepower.

The first of two P.B.31E prototypes was flight tested in early to mid-1917, but its shortcomings were soon exposed. The plane hits just 60 mph (well below the advertised 75 mph limit) and has a poor rate of climb as it takes 60 minutes to reach 10,000 feet. On top of that, the already unreliable engines in the Anzani range tend to overheat when pushed. All of this goes against the maturity of the P.B.

31E at the prototype stage.

With such a display, work on the second still incomplete prototype ceased, while the first prototype was scrapped as early as July 23, 1917 - which completely ended the first superocean project.

Specification

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