M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
Deleted by request of (c)Schiffer Publishing
O.Thetford British Naval Aircraft since 1912 (Putnam)
This little single-seat scout was designed and built in the surprisingly short time of eight days, and it made its first flight in August 1914. It was not produced in quantity, but the prototype was purchased by the Admiralty and served for a time as a trainer at the RNAS flying school at Hendon. One 50 hp Gnome rotary engine. Maximum speed, 78 mph. Climb, 500 ft/min. Endurance, 3 hr. Span, 26 ft. Length, 20 ft.
Flight, August 21, 1914.
THE P.B.IX SCOUTING BIPLANE.
HITHERTO, Mr. Pemberton Billing has confined his attention to the production of seaplanes, but, as mentioned briefly in "Eddies" last week, realising the need at the present time for military biplanes for scouting work, he set to work with commendable enterprise to produce such a machine, capable of being quickly erected and dismantled for transport, and in which the engine might be exchanged for another one of different horse-power in the shortest possible space of time.
In the extraordinarily short period of one week, the designing, construction and finishing of this machine had been completed. The machine would have been put through its trial flights within that time limit but for the fact that there is no suitable ground in close proximity to the supermarine works of Mr. Pemberton Billing at Southampton. As it was, it was tested in the air within the next two or three days, and came well up to its designer's anticipations.
In its general lay-out the P.B. IX Scouting biplane does not differ materially from already existing machines of that type, but its designer has managed to incorporate several cleverly thought out details in the construction. The fuselage, which is of rectangular section, is extremely roomy, and tapers to a vertical edge at the rear. The longerons, which are of ash, converge towards the nose of the machine (when viewed from the side), where they are attached to the front engine bearer. As seen in plan, they run parallel up to the pilot's seat, whence they commence to taper gradually towards the rear. As shown in one of the accompanying sketches, the method of joining struts and cross-members to the longerons of the fuselage is similar to that employed in the Morane monoplanes, and the sketches are self-explanatory.
Mounted between double bearings in the nose of the machine is the engine - a 50 h.p. Gnome is at present fitted, but the fuselage is wide enough to accommodate an 80 if desired - and to the rear of that inside the aluminium cowl in front of the pilot's seat are the petrol and oil tanks, which have a capacity sufficient for a three hours' flight.
In its present form the machine is essentially a single-seater, but the roomy cockpit affords ample accommodation should it be desired to fit an extra seat. Control is by means of a hand wheel mounted on a single central tubular column. Behind the pilot's seat is a transverse rocking shaft, carrying at its ends crank levers from where cables run to corresponding levers on the elevator. Another steel tube connects the vertical control lever with the lower half of the crank-lever on the transverse shaft, thus doing away with crossing of the elevator control cables, which might lead to wear and subsequent breakage.
A fiat non-lifting tail plane is mounted on top of the fuselage and to it is hinged the divided elevator. Pivoted round the tubular extension of the sternpost of the fuselage is the rudder, and a vertical fixed tail fin is fitted. A small sprung tail skid protects the tail plane against contact with the ground.
The main planes are characterised by having their trailing edge slightly longer than the leading edge. They are separated by only two struts on each side, and cross bracing is effected by means of stranded cables. Ailerons are fitted to both upper and lower planes, and are inter-connected by a strut running from the under surface of the upper aileron to the top of the lower one. They are operated by rotation of the hand wheel, and steering is effected by means of a pivoted foot-bar. Near the fuselage the trailing edge has been cut away in order to provide a better view in a downward direction. It is in their attachment to the fuselage, however, that the main planes are chiefly interesting. The spars on both planes run right through the wing from tip to tip, those of the lower plane running underneath the fuselage, to the lower longerons of which they are attached by U-bolts. By undoing these four U-bolts, the wings may be slid over the end of the fuselage and laid on top, and the machine is then ready for transport. This method of attaching the wings has the further advantage that should it be desired to fit an engine of a different horse-power and weight, the longitudinal stability of the machine can be corrected by sliding the wings a few inches backwards or forwards along the fuselage. This feature should be of considerable merit for military purposes, where an interchange of engines may frequently be desirable. Another reason why the light single-seater scout should be useful for military purposes at present is that there are probably a great number of 50 h.p. Gnomes available, fitted to school machines, which would be of no use as military machines, but the engines of which could with advantage be used in a small fast machine of this class.
The chassis is of simple type, and consists of two "V's" of streamlined wood. The axle works in slots in the angle between the front and rear chassis struts. No skids are fitted. The weight of the machine empty is 560 lbs., and with pilot and three hours' fuel, 750 lbs., or a loading of 3-6 lbs. per square foot. The maximum speed with a 50 h.p. Gnome is about 75 miles per hour, and the minimum speed just over 30 miles per hour.
During the preliminary trials a few days ago, already mentioned, P.B. IX got off after a very short run, piloted by Mr. V. Mahl, and appeared to climb at the rate of about 500 ft. per minute.