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.