M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
Deleted by request of (c)Schiffer Publishing
P.Lewis British Aircraft 1809-1914 (Putnam)
Grahame-White Type 13 Circuit Seaplane/Scout
Entry number 4 in the 1914 Daily Mail Circuit of Britain race for seaplanes was the Type 13 built by the Grahame-White concern. The machine was designed by J. D. North and was scheduled to be Claude Grahame-White's mount in the contest. It possessed a neat and workmanlike appearance, with the two seats in tandem and the wings of heavily-staggered, single-bay lay-out. The 100 h.p. Monosoupape Gnome was cowled in aluminium and blended into the fuselage, whose rear end tapered in side elevation to a horizontal knife-edge in the Morane-Saulnier manner. The Type 13 was devoid of a tailplane, utilizing elevators only, also a typical Morane-Saulnier feature. An idea in advance of its time was the addition of an extra strut between each main interplane pair, which connected the upper rear spar to the lower front spar, thus constituting a very early example of the later widely-used N struts. These struts were very strong, comprising steel tubing covered with wood fairings. Decalage was incorporated in the wings' incidence settings, 5° being used in the upper and 3° in the lower. Ailerons were fitted to the upper wings only, and the lower wing roots were given generous cut-outs at the trailing-edge to aid visibility.
The machine was fitted with its floats, and water trials commenced. The floats proved, however, to be too short forward of the engine, and upon the throttle being opened up the seaplane nosed over. The Type 13 was not considered worth developing as a seaplane and was consequently abandoned as the Grahame-White entry for the Circuit of Britain. A land undercarriage was devised and fitted to the machine, which became known as the Scout. In this form it was planned to use it for reconnaissance, but, again, the design was not found successful for the purpose, and the Scout is believed to have been employed as a trainer for the R.N.A.S. at Hendon, where it was flown by Marcus D. Manton.
Description; Two-seat tractor biplane. Wooden structure, fabric covered.
Manufacturers: Grahame-White Aviation Co. Ltd., Hendon, London, N.W.9.
Power Plant: 100 h.p. Monosoupape Gnome.
Dimensions: Span, 27 ft. 10 ins. Length (Circuit Seaplane) 27 ft. 3 ins.; (Scout) 26 ft. 6 ins. Wing area, 290 sq. ft.
Weights: (Scout) Empty, 1,040 lb. Loaded, 1,800 lb.
Performance: Maximum speed, 85 m.p.h. Endurance, 5.5 hrs.
Flight, August 28, 1914.
THE "ROUND BRITAIN" MACHINES.
THE machine officially numbered 4 in the Circuit of Britain was
The Grahame-White Tractor Biplane,
which was to have been piloted by Mr. Grahame-White. During one of its trial flights this machine, it will be remembered, was damaged on alighting, but previously it had shown that it was capable of doing all it was designed to do; in fact, in several respects it exceeded the expectations of its designer, Mr. J. D. North.
To the casual observer the Grahame-White tractor does not differ a great deal from other machines of its type, but a close inspection reveals a number of interesting features, ingeniously conceived and well carried out. One outstanding feature is its small size - the span is only 27 ft. 10 ins., whilst the over all length is just over 27 ft. - which gives one an impression of speed, an impression that is confirmed by actual figures, for the maximum speed is stated to be 85 m.p.h., and that figure can probably be exceeded.
The fuselage resembles that of the Morane monoplane in that it terminates in a horizontal knife-edge at the rear. In section it is rectangular, and the joints between struts, cross-members, and longerons are formed, in the rear portion, in a manner similar to those of the Morane, whilst in front, owing to the different weight disposition, the joints are of varied form.
In the extreme nose of the machine is mounted a 100 h.p. Gnome monosoupape engine, supported on three bearings, of which the front one is self-aligning. An aluminium shield encloses the greater part of the engine and extends backwards up to the passenger's seat. A turtle back consisting of three ply wood in front and stringers covered with fabric in the rear, tops the fuselage.
Pilot's and passenger's seats are arranged in tandem, the former occupying the front seat, which is built into the petrol tank, situated between pilot and passenger. Lateral and vertical control is by means of a single central tubular column, terminating in an elliptical handle on which is mounted the engine switch. A to-and-fro movement operates the elevator, whilst the ailerons are actuated by rocking the lever from side to side. Foot steering is effected by means of a pivoted foot bar mounted on the floor of the fuselage.
In the arrangement of the main planes several departures from usual practice are to be found, notably in the method of strutting employed. Only one set of struts is fitted on each side, but this comprises three instead of two struts. In addition to the struts connecting front and rear spars of upper and lower planes respectively, a third strut runs from the front spar of the lower plane to the rear spar of the upper plane. On account of the very pronounced stagger, this third strut is nearly vertical and is in the same plane as the diagonal bracing cable running from the fuselage to the attachment of the strut to the upper rear spar. From a steel clip on the lower longeron other cables run to the upper extremities of front and rear struts. This method of bracing is somewhat unusual, but in the opinion of the designer combines great strength with low head resistance. The struts themselves are of unusual construction, in so far as they consist of steel tubes totally enclosed in streamline wood casings, a construction which renders them immensely strong. They are attached by means of steel clips gripping the spars without piercing them. The latter are of hollow section and bound with fabric, and during a test to which one of these spars was subjected it carried a load of eight times the weight of the whole machine without any perceptible deflection.
In addition to the heavy stagger the main planes are interesting on account of the fact that the lower plane is set at a smaller angle of incidence than the upper one, the two angles being 3° and 5° respectively. The object of this arrangement is to improve the longitudinal stability of the machine, and the results obtained in practice show that it answers its purpose, A dihedral angle of 2° to the lower plane increases the lateral stability. The upper plane, which is straight, is fitted with interconnected ailerons. In order to give a good view from the pilot's seat in a downward direction, the trailing edge of the lower plane has been cut away near the fuselage. From the passenger's seat the view in a forward and downward direction is practically unobstructed, and that it is comparatively easy to get out of in case of a smash was proved by Mr. North recently, when he managed to "bubble" to the surface when his seat was totally submerged.
At the rear of the fuselage are carried the tail planes, which resemble those of the Morane monoplanes as regards the elevator. No stabilizing plane is fitted, but a vertical fin extends forward from the rudder. A small metal float takes the weight of the tail planes when the machine is at rest.
The chassis consists of two floats, carried on a structure of four stream-line steel tubes, held rigid by means of stout stranded cables.
With full load on board, including 50 gallons of petrol, 9 gallons of oil, or sufficient for a flight of 5 1/2 hours' duration, passenger and pilot, the machine develops a speed of about 85 m.p.h.
Flight, April 16, 1915.
IT was a pity that the high wind prevailing on the first days of the Easter meeting at Hendon and a refractory engine on the Monday prevented the visitors from seeing the Grahame-White tractor showing her paces. Manton decided, very wisely, that in view of his short experience on so fast a machine it would have been unwise to try her out in such a vicious wind. He got her going for a couple of nights, and then the engine decided, it being a Bank Holiday, to take a rest. So it came about that Manton had to abandon his intention of giving a demonstration of speed flying for the benefit of the crowd of visitors which had gathered in the afternoon. It is, however, only an attraction postponed, and I shall look forward to her proper debut at the next meeting of the season.