Flight, February 1931
GLIDING IN THE TRANSVAAL. - Mr. S. W. Vine sends us the following information of a glider which hr. has designed at Krugersdorp, Transvaal, South Africa. The country where he has carried out his experiments has an altitude of over 6,000 ft., and his experience
should prove of interest. It will be seen from the illustration that the glider is a high-wing monoplane type, and the following are the rough details :- Span, 40 ft. 8 in.; length, 23 ft.; mean chord of main plane, 5 ft.; depth of main plane spar, 7 in.; area of elevator, 24 sq. ft.; rudder area, 11 sq. ft.; weight empty, 242 lb. The material used for the construction is chiefly American ash and the wing section is a modified Gottingen. Preliminary trials of the machine were carried out on a fairly flat veldt. The launching was carried out by means of 1,000 ft. of flexible steel cable, 1/4-in. diameter, connected to a steel drum of 16-in. diameter revolving on the jacked-up rear axle of a Ford car (the differential being locked). The connection of the cable to the glider was by the usual hook and ring. This method was found to be quite successful and perfectly safe and economical, since it required only one person for a launching crew. Speeds up to 30 m.p.h. were easily obtained, and the ring could be released from the hook immediately by simply closing the throttle of the car. During the first flights it was found that a speed of 8-10 m.p.h. into a light wind of about 5-6 m.p.h. would lift the glider to a height of 35-40 ft., and this exceeded expectations, having regard to the speed, lift, and weight ratios and the altitude of the situation. Further trials were, unfortunately, cut short, since a native who was left in charge let go of the machine immediately he felt it move in the wind and it was blown across country. Mr. Vine has now completed a second machine of a more orthodox type and we hope to publish details of this later.