The Boulton & Paul P.10 was the first practical all-metal aircraft to be produced in Britain.
John North, the chief designer at Boulton & Paul, had come to believe that metal was the best material for aircraft structures, offering the potential to be stronger and lighter than wood. This was a somewhat ironic position for Boulton & Paul to take, as the company had originally been a woodworking business, and it was their skills with wooden construction that had led them into the aircraft industry.
Work on the P.10 was encouraged by the Air Ministry, which was becoming worried about a shortage of suitable spruce for aircraft construction.
The wings and horizontal tail surfaces were rectangular, with squared off ends, something that became a standard feature of Boulton & Paul designs for many years. The wings were of equal size, and were unstaggered, and the gap between them and their chord were both 5ft 6in. The vertical fin and rudder were curved. The upper wing had a curved cut-out section
The P.10 was a two-man aircraft, with two separate open cockpits - one just below the leading edge of the wing and one just behind the trailing edge. Both cockpits had full flight controls, and a large windscreen.
The structure of the P.10 was constructed from high tensile steel. At the time high quality steel tubes were difficult to come by, and so Boulton & Paul made their own by rolling long steel strips.
The covering of the fuselage used Bakelite-Dilecto, a cellulose-formaldehyde based plastic that had been developed by Boulton & Paul, and that was the first plastic to be used in any aircraft structure.
The P.10 was powered by the odd Cosmos Lucifer engine, a three cylinder radial engine that was based on the nine cylinder Cosmos Jupiter. The Lucifer provided 100hp at 1,700rpm. The engine was carried on a hinged mounting, with one long hinge bolt on each side. When one bolt was removed, the other could be used as a hinge to move the engine to one side to allow access to the magneto and carburettor, without needing to disconnect any of the fuel or other pipes.
The P.10 was displayed at the Paris Salon d'Aeronautique of 1919. The structure of the wings and tail was on display, but the fuselage and engine were covered, to hide the use of plastic in the fuselage and the swinging engine mounting. This open display shows the two I spars on each wing - one just back from the leading edge and one close to the middle, the regular ribs, and the four ailerons, two on each wing. The P.10 was said to have been the machine of the show, and the only technological advance on display in the entire show.
After Paris the fate of the P.10 is unclear. It wasn't displayed at Olympia in 1920, and may have suffered damage during an engine test. It doesn't appear to have ever flown, probably because by 1920 it was clear that there wasn't a commercial market for new aircraft, when so many wartime surplus aircraft were available at very low cost. Despite this obscure fate, the tail and one wing of the P.10 survived, and are now in the collection of the Bridewell Museum, Norwich, making it the oldest British metal aircraft wing to have survived.
Performance figures estimates
Engine: Cosmos Lucifer
Maximum take-off weight:
Max speed: 104mph at 1,000ft
Climb Rate: 8 min to 5,000ft
Service ceiling: 14,000ft
Endurance: 3h 30min at 100mpg at 3,000ft; 5h at 90mph at 3,000ft