Page:Aerial Flight - Volume 2 - Aerodonetics - Frederick Lanchester - 1908.djvu/41

Rh aeroplane, or, indeed, of the existence of Moullard's work at all, and it is not surprising, therefore, that his models were designed and constructed on entirely different lines.

In the author's original model (Figs. 14 to 20), the various functions that are performed incidentally by the ballasted aeroplane in the maintenance of equilibrium are carried on by special organs, and this fact, which arises from the theoretical origin of the appliance, renders it particularly well suited to analytical study.

One of the deductions from the author's preliminary investigations was in effect that the higher the velocity of flight the greater the stability attainable; the models employed were, in pursuance of this conclusion, designed for velocities of some 40 miles per hour and upwards. It was estimated that such a velocity would render the stability independent of any gusts of wind such as would ordinarily be encountered, a result that was fully substantiated by the subsequent experiments.

Owing to the high velocities employed the launching had to be effected by means of a catapult, the construction of which is illustrated and described in § 12 (Fig. 21).

'''§ 11. Author's Experiments (continued). The Aerodone.'''—The form of aerodone employed by the author in these experiments is drawn to $1⁄10$ scale in Figs. 14, 15 and 16, and a photograph reproduction is given in Fig. 17. Further details are given in Figs. 18, 19 and 20.

The aerofoil sections D, E, F, G (Fig. 19) being of elliptical plan-form 40 in. by 8 in., and the aspect ratio, n being 18.3, the actual area = .65 sq. ft. On the basis of a parabolic grading, the effective area, given by the expression $2 l^{2}⁄3 n'$ = .55 sq. ft. The centre of gravity of the aerodone is arranged about 1 inch from the front edge of the aerofoil, the latter being the unique organ of sustentation.