Wallbro

CAMBRIDGE DAILY NEWS, THURSDAY 12TH MAY 1910

ALL-BRITISH AEROPLANE.
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Made in Cambridge.
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Light and Graceful Machine
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(“CAMBRIDGE DAILY NEWS” SPECIAL)

Snugly housed in a shed in the rear of a house in St. Barnabas’ Road, Cambridge, reposes a brand new flying machine of the monoplane variety, which has been designed and built by two Cambridge men, and every particle of which is of British manufacture. A representative of the “Cambridge Daily News” had an opportunity of inspecting the machine on Wednesday, and seeing the engine and elevating and steering apparatus tested, and came away greatly impressed with the extremely graceful and workmanlike lines on which it is built, and with sound and truly British work that has been put into it. The machine embodies a number of novel ideas, and the builders claim for it that it is one of the lightest and strongest machine yet made.
If not exactly the first flying machine that has been seen in Cambridge, it is certainly the first one built in the town, and the Bros. Wallis, the builders, are hopeful of demonstrating before long it’s capabilities in the air. When it was seen on Wednesday, the Bros. Wallis were busy putting the finishing touches to it. It resembles somewhat the Bleriot and Antoinette monoplanes, yet it differs from both these machines in several important particulars. One of these is the construction of the frame work.

A FINE PIECE OF WORK

Messrs. Wallis are strong believers in the merits of steel tubing, and they have succeeded in producing by it’s use a machine at once light and strong, lighter than either of the aeroplanes mentioned, and, they believe, quite as strong, if not stronger. It certainly makes a very elegant machine, and every part of it is …this part was unreadable…, and altogether it is a very pretty piece of work. From the boss of the tractor screw in front to the tip of the rudder the frame measures 25 feet, and the wings or planes have a 30ft. span and a sustaining area of 180 square feet. The greater part of the frame is constructed of one inch, 20 gauge tubing, arranged on the girder principle and strongly braced with steel wires. The cross tubes are double bolted into steel lugs similar to those used in motor-cycle construction. The wirestays are attached to eye-bolts passing through these lugs, and the wires are tightened by means of bronze tensioning screws having a right and left hand thread, so that the wires can be tightened by merely turning the screw round by means of a small tommy bar. An ingenious little arrangement is provided which prevents the screws coming accidentally untwisted through vibration or other flying strains. The frame tapers slightly from the head for a little over half it’s length, when the taper becomes more pronounced, the arrangement of the tubes at this point being designed to strengthen the frame against landing shock.

THE CHASSIS

The chassis, or under-carriage to which the wheels on which the machine runs before rising into the air are affixed, is built of 18 and 16 gauge tubing. The wheels are placed at the back of the chassis, a pair of stout ash skids with upturned ends being fixed to the forward ends of the chassis. These skids are to enable the machine on landing to slide along the ground until the wheels touch the ground. The chassis is attached to the main frame at the forward end, below the engine, by means of stout tubes, which carry a cross-bar on which the chassis can move on a kind of hinge, so that when the skids touch the ground they tilt the chassis so that the wheels come into action, the shock being taken up by strong tension springs attached to each end of the chassis. The wheels are very strongly, yet lightly, built. They are 24in. in diameter, and have 7in. hubs, running on plain bronze bearings. Each wheel, complete with 3in. pneumatic tyre, weighs only 3½lbs., some of the lightest ever put on an aeroplane. The tyres are special aeroplanes ones, manufactured by Messrs. A. V. Roe and Co., London and Manchester. They are chiefly composed of canvas, vulcanised, with a thin layer of rubber on the tread. The small amount of rubber in their composition, of course, allows of their being so light. They have no beaded or wire edge, and are held on to the rim by the pressure of the air inside, so that the harder they are pumped the tighter they grip. Being of such wide section, they are especially suitable for running over the marshy ground often met with on flying grounds. The after part of the machine is supported on the ground by a single pneumatic shod cycle wheel…this part was unreadable…tube fastened to the under side of the frame, carrying a coil spring under compression, which enables the wheel to give to the shock of landing or going over bumpy ground. The total weight of the machine is 330lbs. with full oil and petrol tanks.

THE MOTIVE POWER

The motive power is furnished by a four cylinder J.A.P. aeroplane petrol motor, and built by the famous firm of J.A. Prestwich and Co. (Tottenham). The cylinders are set at an angle of 120 degrees, and each cylinder has a 95 millimetre bore by 110 stroke. The engine, which weighs 130lbs., develops 25 horse power at 1,500 revolutions per minute; but as it can work up to 2,000 revolutions it has an ample reserve of power. Each cylinder is drilled at the bottom of the piston stroke with a number of auxiliary exhaust ports. Following the usual aeroplane practice the exhaust pipes have no silencers, and discharge direct into the air. The lubrication of the engine is affected by means of two patent J.A.P. automatic lubricators. The tractor screw is Messrs. A.V Roe and Co.’s patent adjustable, mounted on the crank shaft of the engine. The crank shaft, it may be mentioned, is hollow, and, as the engine is set traversely in the frame, there is a free passage of air right through the shaft, thus helping to keep it and the bearing cool. The tractor consists of two walnut wood blades fixed to two detachable brass arms fitting into brass sockets, so that in the event of either blade being damaged another can be inserted. The arms are, for security, double bolted into the sockets. The pitch of the tractor screw is 2½ft. and the sweep of the screw is 6ft. 6in., so that it should enable the machine to attain a speed of 40 miles an hour with the engine making 1,500 revolutions per minute. The oils and petrol is carried in a cylindrical copper tank, with pointed ends, mounted between the engine and the driver’s seat. The tank will hold 1½ gallons of petrol and ½ gallon of oil. Ignition is by a Bosch magneto, gear driven off the engine shaft. The engine is supplied with gas by means of a J.A.P. patent carburettor, with automatic air inlets, and admission of the air being controlled by a number of balls covering the air-holes, arranged so that as the suction of the engine increases the balls are lifted on after the other and allow more air to enter.

THE CONTROL

The engine is controlled by two thumb-slides, moving wires attached to the throttle and spark levers, and the ignition can be cut out and the engine stopped by means of a thumb switch similar to those in use on motor cycles. The main planes or wings are fixed each side of the head of the machine. They are of cream coloured pegamoid, which is waterproof and very light, stretched over a hollow framework of ash strips mounted on one-inch steel tubes. In order to keep the machine on an even keel when in the air the wings are not warped, as in the case of the Bleriot machine, but the desire effect is obtained by moving two “ailerons,” each about 8 square feet in area, are pivoted on one of the steel tubes forming the main supports of the wings. The movement of the “ailerons” is controlled by wires connected with a steering wheel placed in front of the driver and on his left hand. This enables the “ailerons” to be tilted up or down as required. When not in use the “ailerons” are kept level with the surface of the wings by means of tension springs. The rudder is also of pegamoid on an ash framework. It has an area for about eight square feet and is controlled by wires attached to a tiller arrangement worked by the drivers’ feet. The aviator sits in a bucket seat in the framework about four feet behind the engine. The elevating planes and tail supporting surface are fixed to the framework a few feet in front of the rudder. The supporting surface is about 12 square feet in extent and is rigidly fixed at the same angle as the wings. On each side of the supporting surface are the elevating planes, each nine square feet in number controlled by wires worked by another wheel placed to the right of the drivers seat. With the exception of the engine, tractor, magneto and carburetter, the whole of the machine has been built by Mr. Percy Valantine Wallis and Mr. Horrace Samuel Wallis, of 12, St. Barnabas Road, Cambridge, two gentlemen well-known in motor cycle racing circles, whose successes last year at the Mamouth Show and other motor cycle races in various parts of the country will be remembered, and the machine is garaged in a large shed which they have erected for it in the garden of No. 12. The engine was tested for a few minutes yesterday and ran splendidly. It proved to be a very easy starter, going off at the first pull of the tractor over compression after the right mixture of gas and air had been found. It very quickly developed a good rate of speed and gave every promise of being capable of sending tha machine along at a good 40 miles an hour. The power of the engine, although it was never at full throttle, was evidenced by the way the “Wallbro” tugged and stained at the ropes that held it to the ground.

8th July 1910

The “Wallbro” Aeroplane. – A Peculiar accident occurred to the new “Wallbro” all-British aeroplane, built by Messrs. P. V. and H. S. Wallis, of Cambridge on Monday during the course of a trial run. Through so means or other the machine turned a complete somersault and, although Mr. P. V. Wallis, who was driving jumped to the ground unhurt, the aeroplane suffered considerable damage. The machine, which is housed in a field near Abington landed upside down, Messrs. Wallis Bros. are by no means disheartened through the accident.

Wallbro Monoplane (Courtesy Ken Wallis)

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