Flight, July 1920

The Olympia Aero Show 1920

The machines

Martinsyde, Ltd. (STAND 43) Maybury Hill, Woking.

   THREE types of Martinsyde aeroplanes are shown on this stand, as follows: The "A" type Mark II, the F.4A two-seater, and the "Semi-quaver." The former machine has been designed to fill the demand for a commercial aeroplane of low capital cost and maintenance. The example shown is arranged to seat four passengers and the pilot, while provision is made for a small amount of hand luggage. The passengers are comfortably seated facing forward, and are in an excellent position for obtaining a view of the country over which they are passing. The passengers' cabin is so arranged that it can be either closed or open to suit the requirements of the individual buyer or the climatic conditions under which the machine will be used. The pilot is located immediately behind the cabin, some distance aft.
   The machine is fitted with a 300 h.p. Hispano-Suiza engine and has a cruising speed of 100 m.p.h. The radiator is mounted in the nose of the fuselage. A compressed air starter operated from the pilot's seat is fitted, and duplicate instruments are provided for the passengers. Floats and float undercarriage are also shown in connection with the A Type machine, and can be readily substituted for the land undercarriage, converting the machine into a remarkably serviceable and efficient seaplane. The floats are constructed of consuta wood, and are fitted with two steps built on to the main structure. They are divided into four watertight compartments, and provision is made for the wheels to be fitted to an axle passing through the floats for beaching and launching purposes. The undercarriage itself consists of four spruce struts with metal shoes transmitting the weight from the fuselage to the two axles, which in turn distribute it over the floats. The whole structure is braced with heavy gauge streamlined wires, and forms a unit of unusual strength and low head resistance.
   In other respects this machine is of typical Martinsyde construction and design. The main planes are of equal span and chord, with the top plane staggered forward, and two pairs of interplane struts each side. Ailerons on both upper and lower planes.
   The F.4A Two-seater is an adaptation of the famous Martinsyde "Buzzard," and combines the qualities of great strength and high performance which made that machine the most efficient fighting scout in 1918. The example shown is fitted as a two-seater with dual controls. It is an excellent school machine where it is necessary for pupils to become accustomed to handling fast aeroplanes. It is ideal for sporting and touring purposes, or for postal and commercial services where high speed is essential.
   The right-hand bottom wing is left uncovered by fabric, and shows in more detail some of the outstanding features of Martinsyde construction. The wing spars are built up of three laminations, thus eliminating the possibility of fracture through an undetected flaw in the timber. The fittings which take the flying wires and struts are so constructed as to go round the whole spar, the spar only being pierced through its neutral axis. Interplane struts, of which there are one pair each side, arc fitted by means of metal shoes dropped over a Duralumin block on the main spar fitting.
   In this machine the top plane is of slightly larger span and chord than the lower. As in the other model the engine is a 300 h.p. Hispano-Suiza, mounted in the nose of the fuselage behind the radiator.


The Martinsyde Machines

   In constructional details the Martinsyde machines exhibited follow more or less standard Martinsyde practice. An excellent idea of the wing construction is given on one of the machines, the Type F4A, by leaving the right-hand bottom wing uncovered, so that all the constructional details can be inspected. As always, the Martinsyde workmanship is exceedingly good, and there is evidently no intention on the part of the firm to scamp work in any way anywhere in order to lower the price.
   The wing construction of the Martinsyde machine is interesting, in that the spars, although of "I" section, are built up of three laminations, a thin lamination in the middle, with two thicker laminations at the front and back. These outer layers are spindled out in the usual manner to form, with the centre strip, an "I" section, but the difference is that thinner strips of wood are used, and that, therefore, all small flaws in the wood are more easily detected than is possible where the spars are spindled out of a solid piece of wood. The attachment of the interplane struts and lift wires to the wing spars is also worthy of notice. The strut rests on a packing piece of duralumin which is held in place as shown in the sketch. The straps for the lift and anti-lift wires pass down the front and back of the spar and around the opposite side of the spar, the only piercing thus being for horizontal bolts on the neutral axis, which does not in any way weaken the spar.
   The body construction of all the Martinsydes also follows standard Martinsyde practice, which has stood the test of time and experience. As regards two of the machines shown, the F4A and the "Semiquaver," the front portion of the body is covered with three-ply wood, whereas in the cabin machine the fabric covering extends forward right up to the engine housing. The upper part of the body of the latter machine, however, is finished in mahogany, with Triplex windows, and the roof over the cabin is in the form of gauze to ensure thorough ventilation of the cabin.

Flight, August 1922

A MARTINSYDE FOR NEWFOUNDLAND
The Type A, Mark II, Sold to the Aerial Survey Co.

   At the last Olympia Aero Show there was, it may be remembered, exhibited, among other machines, a commercial aeroplane with seating accommodation for four passengers, in addition to the pilot. This machine was known as the type A, Mark II, and had a 275 h.p. Rolls-Royce "Falcon" engine. Recently, this machine has been purchased by the Aerial Survey Co., of Duckworth Street, St. John's, Newfoundland, for use in spotting for seals. During the last year or two, it will be remembered, Mr. F. S. Cotton and Mr. A. S. Butler, the latter of whom is now a director of the De Havilland Aircraft Co., have been doing some extremely useful work in Newfoundland, surveying, spotting for seals etc., the machines used being de Havillands and Westlands. The "stable" will now be increased by the Martinsyde type A, Mark II, which has been specially fitted out for the purpose. Last week, through the courtesy of Mr. Tilghman Richards, of Martinsydes, we had an opportunity of examining the machine at the Woking works of that firm when the accompanying illustrations were obtained.
   The Martinsyde A, Mark II, or A.II for brevity, is a tractor biplane resembling in general lines the well-known Martinsyde F.4, which is one of the most beautiful aeroplanes ever designed. The A.II, however, has a high coaming forming the cabin top, which is provided with windows in the sides, and has a gauze cover to combine top lighting with ventilation. The general arrangement of the machine will be gathered from the accompanying scale drawings.
   The fuselage is a girder structure braced by tie rods except in the front bay, behind the engine housing, where bracing as well as covering is effected by "Consuta" ply-wood. The covering of the rear portion is fabric, doped with "Cellon" aluminium dope. The sides of the cabin top are of mahogany, and slope slightly inwards so as to bring the centre-section bracing outside the cabin. The space inside the cabin is divided into two by the seating arrangement, which consists of two pairs of side-by-side seats, the front one of which is reached by stepping over the back rest. In order to facilitate this somewhat acrobatic feat the roof of the cabin is hinged, as regards the rear portion, so as to lift up, while the front portion runs on guide rails and can be pushed forward out of the way while the passengers are getting in or out. There movable portions of the cabin roof are, as already mentioned, covered with a fine gauze, which not only helps to light the cabin, but has been found to give excellent ventilation without draught.
   The pilot's cockpit is aft of the cabin, and a special windscreen has been fitted, at the request of Mr. Cotton, we believe, so as to shelter as much as possible the pilot against the icy winds met with in Newfoundland. The controls are of the usual Martinsyde type, but the instrument board is rather more completely equipped than on standard machines. This is, of course, a result of the special work for which the machine is intended. Among the instruments is found, as indicated on one of the accompanying sketches, a Vickers-Reid gyro turn indicator, an instrument which is rapidly becoming popular on all civil aircraft, enabling as it does the pilot to know at all times, even in the dark or in clouds, what his machine is doing.
   A wireless outfit is installed in the upper forward compartment, above the main petrol tank, and a hinged partition enables the operator to get at his instruments, while a removable panel in the side also gives access to the wireless compartment when the machine is on the ground. In the floor of the cabin, near the front wall, is an opening and mounting for an aerial camera, so that it will be possible for the machine to go out, locate the herds of seals, wireless the position to the base, and finally photograph the herds and bring back to the base pictures showing the exact nature of the herds and their numbers. Thus, when the sealing fleet puts to sea, it should do so with a maximum of advance information, instead of having to waste, perhaps, many days or even weeks locating the herds.
   As the machine will be used at all times of the year, the question of heating assumes some importance. In the Martinsyde A. II an attempt has been made to solve the problem by running a pipe of some 2 ins. diameter from the engine housing to the cabin. At its front end, which rests immediately behind the radiator, this pipe has a large funnel almost touching the radiator. Thus, the air which enters the pipe has already been slightly heated by passing through the radiator, while it is further heated by lying close to the exhaust pipes of the port cylinders. By means of a small lever, working in a semi-circular groove in the cabin "table" (shown in one of the sketches), the passengers are able to regulate the amount of hot air entering the cabin.
   In view of the fact that the Martinsyde will be used extensively over the sea, a pair of floats are being provided, which, by being fitted in place of the wheels, turn the machine into a seaplane. These floats are designed to be fitted with a minimum of trouble, and the change can be effected in a very short time.
   The Rolls-Royce "Falcon" engine is carried on tubular engine bearers, and a fireproof bulkhead separates it from the cabin. The main petrol tank is placed in the lower portion of the fuselage, behind the engine bulkhead, and a small gravity tank is mounted in the centre-section of the top plane. A nose radiator, provided with shutters, is fitted in front of the engine.
   The machine is being crated for shipment, and within a few weeks it should be at work in Newfoundland, when, if the fates are kind, we hope to be able to record some of its doings.