With a view to illustrating some of the models described in this book complete, some drawings are given of the more successful designs which have come into prominence during the past eight years. Fig. 11 shows the Ridley Monoplane, which secured several well-merited rewards in open competition, and is an excellent machine for distance. Birch should be used for the longerons, preferably of channelled section. The main plane is of piano wire, covered with proofed silk, and the elevator is entirely of extremely thin veneer. Bentwood screws are used fairly short in diameter and of long pitch. The machine is capable of flying a quarter of a mile. The Fairey type of model aeroplane typified in Fig. 12 is a most successful type, and has achieved much in open competition. It has what is known as a floating tail, with no leading stabilising surface, but a small vertical fin is used. This is a practice the waiter is not personally in favour of, as through such a long lever the slightest wind will cause great instability. If a vane or fin must be used, it should be placed as far to the rear of the machine as possible, preferably just behind, or in front of the propellers for pusher machines, and the extreme end of the tail for the tractor type.
The swept-back wing tips should have a negative angle of about two degrees, and the tail should be quite flat in relation to the horizontal.
Fig. 13.—Clarke Type Monoplane
Fig. 12.—The Fairey Monoplane
Fig. 11.—The Ridley Monoplane
It has been stated that this machine is a highly successful one; it is also exceedingly intricate in adjustment, and requires very calm weather indeed to secure successful flights. It has also been flown with great success by Mr. Houlberg, who at one time held the official duration record of 89 secs with his machine. The long unrelieved length of spar projecting forward of the main surface detracts much from its appearance in the air. A machine of this type should not weigh more than 8 oz., and is capable of a flight of at least a minute in duration. The simple 1-1-P¹ type drawn in Fig. 13 was formerly popularised by Mr. T. W. K. Clarke, of Kingston, who used all-wooden surfaces, a solid spar and bentwood screw built up in two halves. This method of screw manufacture is unique, since it enables the two blades to be prepared from jigs to a greater degree of accuracy than when it is bent from one piece. Moreover, the lapping of the two halves at the boss imparts strength to the boss where it is most needed. Fig. 14 is a type of tractor monoplane very successful for duration, capable of doing a minute at an altitude of forty feet. The rudder of tractor machines must always be placed above the thrust line and also above the centre of gravity, so that should a side gust strike the machine, the latter does not rock laterally in the air, as a couple is set up between the underhung load and the rudder.
The winner of the Wakefield Gold Challenge Cup is shown in Fig. 15. It was designed by Mr. E. W Twining, one of the early experimenters, for duration, and in the winning flight scored a duration of sixty-five seconds. It is a very pretty and stable flyer, and will rise from the ground after a run of about five feet.
Fig. 14.—Tractor Monoplane
Fig. 15.—Twining Monoplane
Fig. 16.—Bragg-Smith Biplane
Fig. 16 is of the Bragg-Smith biplane, which first came into prominence at Wembley in 1909. The original machine was a huge machine some four feet in span, possessing a propeller of large diameter, large blades, and large pitch—quite the antithesis to ordinary practice. Latterly, however, Mr. Smith has developed his machines into twin-screw, and no doubt is entertained that even better results are obtained with this arrangement.
Fig. 18.—Tandem Monoplane
Fig. 17.—Tractor Hydro-Biplane
Fig. 21.—Fuselage Biplane
Fig. 22.—Blériot Type Tractor Monoplane
Fig. 20.—Tractor Biplane
Fig. 19.—Twining Hand-launched Biplane
It should be pointed out, in passing, that this machine is the subject of a patent for stability, it being claimed that greater lateral stability is obtainable from the curved lower mainplane. A sketch is also given in Fig. 17 of a tractor hydro-biplane. This should weigh about 12 ozs. finished. The tandem monoplane shown by Fig. 18 is another machine which has scored many successes in the early days of model aeroplaning at the Crystal Palace. Figs. 19, 20, 21, 22 show the Twining hand-launched biplane, a tractor biplane built by the writer, a fuselage biplane (canard or screw behind), and a Blériot type tractor monoplane.
A tractor machine is one having the screw in front, and a “canard” or “pusher” machine has its screw behind. It is best to designate the machine by the type formula. Thus, a pusher monoplane with twin screws would be a 1-1-P²-0 type. If it had a tail it would be 1-1-P²-1. A twin-screw “pusher” biplane with or without tail would be 1-2-P²-1 and 1-2-P²-0 respectively. A pusher monoplane with only one screw is a 1-1-P¹ type. A tractor monoplane with single screw is P¹-1-1; a tractor biplane with single screw is P¹-2-1. If a biplane tail is also used it becomes P¹-2-2. If twin screws are used it would then become P²-2-2, and so on.