Page:Aerial Flight - Volume 2 - Aerodonetics - Frederick Lanchester - 1908.djvu/381



Chap. I, mention has been made of an aerodrome constructed by the author in 1894; a representation has been given in Fig. 24, and particulars of a successful flight in § 14. A photograph of this machine is given in Fig. 163, taken at the time of the experiments, and a scale drawing in Fig. 164.

The general construction is evident from the drawing, and follows closely on the lines of the aerodones fully described and figured in § 11. Owing to the greater size and weight of this machine, it is stayed by piano-wire guys in the manner shown, in order to provide longitudinal stiffness both vertically and horizontally.

The propulsion is, as figured, by twin propellers driven by twisted "elastic" (indiarubber), the data of the propelling mechanism being as follows:—

Propellers, 17½ inches diameter; two blades of approximately 6 square inches each; pitch recorded as 16 inches, but on remeasurement it appears to be nearer 20 inches. The construction of the propellers is shown in detail in Fig. 165; the blades are of sheet aluminium .08in. thick, (='75 m.m.), mounted on arms formed by a single steel wire of .1in, diameter. The propeller blades are so fitted as to " feather " automatically if the aerodrome overruns the range of the propulsion; that is to say, when the twisted rubber is spent, the blades swivel approximately into the line of flight and do not act as a drag on the machine. This feathering of the blades is accomplished by mounting them