Prior to becoming the storied "Supermarine" concern of World War 2 fame, the company existed under the Pemberton-Billing brand label. One of the company's earliest original projects became the P.B.23E pusher biplane fighter of 1915. In December of 1916, the company officially changed its name to the better-remembered Supermarine brand and its first project under this title was the "P.B.31E". The P.B.31E was based in the earlier, ultimately abandoned, P.B.29E "Nighthawk", a twin-engined quadruplane interceptor, but had little impact (if any) in the war effort for Britain.
The original P.B.29E was conceived of as a Zeppelin/airship hunter and developed around the concept of long-range / long-endurance for operations principally in low-light hours. A complete set of four wing mainplanes was featured to provide the needed lift, drag, and maneuverability of the gunnery platform. Three crewmembers were carried aloft with the third set to manage a single 7.7mm machine gun at the center-section of the fuselage. The massive aircraft was quite the spectacle for its time, its stacked mainplanes rising high into the sky.
This aircraft was completed and flown during late-1915 into early-1916 but was eventually lost to accident during testing. Nevertheless, the concept was interesting enough to British authorities that another version of this aircraft was furthered - this to become the P.B.31E.
From the outset the P.B.31E needed the range and loitering times envisioned for the P.B.29E for the aircraft would have to be present prior to the arrival of German airships in British airspace. From there, the aircraft would need the firepower and performance to bring these fragile airships down before they could reconnoiter or drop their modest war loads on the British populace or targets-of-opportunity. Engineers estimated their new design to have an endurance window of some eighteen hours of flight time which was a very optimistic proposal.
For power the design team selected a pair of Anzani 9-cylinder air-cooled radial piston engines, each outputting 100 horsepower and driving multi-bladed propeller units in typical puller fashion.
Proposed armament was centered on 1 x 37mm Davis Gun cannon (detailed in the Small Arms section of this site) at the nose (also included here was a generator-fueled searchlight) fed by a stock of twenty projectiles. Supporting this was a trainable 7.7mm machine gun aft of the Davis Gun's position as well as a second 7.7mm machine gun also located aft of the top wing. All told, this provided the crew with formidable firepower at range.
Flight testing of the first of two P.B.31E prototypes was undertaken in the early-middle part of 1917 but its failings quickly shown through. The aircraft only managed a speed of 60 miles per hour (far short of the advertised 75mph limit) and its rate-of-climb proved poor as it took sixty minutes to reach 10,000 feet. On top of this was the propensity for the already unreliable Anzani series engines to overheat when pushed. All this worked against the P.B.31E seeing maturity in its prototype stage.
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(OPERATORS list includes past, present, and future operators when applicable)
INTERCEPTION
Ability to intercept inbound aerial threats by way of high-performance, typically speed and rate-of-climb.
X-PLANE
Aircraft developed for the role of prototyping, technology demonstration, or research / data collection.
Length
37.0 ft (11.28 m)
Width/Span
60.0 ft (18.30 m)
Height
17.7 ft (5.40 m)
Empty Wgt
3,682 lb (1,670 kg)
MTOW
6,173 lb (2,800 kg)
Wgt Diff
+2,491 lb (+1,130 kg)
(Showcased structural values pertain to the Supermarine P.B.31E production variant)
Installed:
2 x Anzani 9-cylinder air-cooled radial piston engines developing 100 horsepower and driving multi-bladed propeller units in puller fashion.
(Showcased performance specifications pertain to the Supermarine P.B.31E production variant. Performance specifications showcased above are subject to environmental factors as well as aircraft configuration. Estimates are made when Real Data not available. Compare this aircraft entry against any other in our database or View aircraft by powerplant type)
PROPOSED:
1 x 37mm Davis Gun cannon.
1 x 7.7mm trainable machine gun aft of Davis Gun mounting.
1 x 7.7mm trainable machine gun aft of uppermost wing member.
Supported Types
(Not all ordnance types may be represented in the showcase above)
0 Hardpoints
P.B.31E - Base Series Designation; one flyable prototype completed; second incomplete prototype scrapped.
General Assessment
Firepower
Performance
Survivability
Versatility
Impact
Values are derrived from a variety of categories related to the design, overall function, and historical influence of this aircraft in aviation history.
Overall Rating
The overall rating takes into account over 60 individual factors related to this aircraft entry.
48
Rating is out of a possible 100 points.
Relative Maximum Speed
Hi: 100mph
Lo: 50mph
This entry's maximum listed speed (75mph).
Graph average of 75 miles-per-hour.
City-to-City Ranges
NYC
LON
LON
PAR
PAR
BER
BER
MOS
MOS
TOK
TOK
SYD
SYD
LAX
LAX
NYC
Operational range when compared to distances between major cities (in KM).
Max Altitude Visualization
Design Balance
The three qualities reflected above are altitude, speed, and range.
Aviation Era Span
Showcasing era cross-over of this aircraft design.
Unit Production (2)
2
36183
44000
Compared against Ilyushin IL-2 (military) and Cessna 172 (civilian).
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United Kingdom (cancelled)
