"AIR-SAILING."

Dunstan Times, Issue 3141, 30 October 1922, Page 2

"AIR-SAILING."

(By Harry Harper). Not long ago Klemperer. whom one might call the "father" of the very modern, post-war school of German airsailors, went one morning to the top of Wasserkuppe, the gliding-hill which towers 3000 feet high, and, after studying with silent absorption the direction and strength of the wind, pointed away across a valley, and declared: "I will 'sail-plane' there today!" And he did. That keen-eyed scrutiny of bis of the way the wind was blowing over slopes and ridges told him that, starting as he was from the hilltop, with an altitude already gained of 3000 feet, he could so manoeuvre himself into a series of upward gusts, each of which would give him, "lift." that he could air-sail mile after mile, and so reach any definite objective within reasonable distance—always provided that this objective lay in a direction made favorable by the prevailing wind.

And Klemperer, agile as n hire] in his feather-weight framework of wings. did heat to and from and "tack" hero and there over the rising ground and valleys, until finding himself still several hundred feet high and within ordinary gliding reach of his goal, he sailed down in one long straight dive, and alighted gently in a field within a stone's throw of the village street. Now take this further illuminating fact. The best of the little motorless air-yaehts so far built has a gliding angle of 1 in 16. Putting this quite simply, it means that if the machine is launched from a hilltop, and glides through still air under the downward pull of gravity, its wings are so efficient, and its resistance to its own progress so small, that it will move 16 feet horizontally for every foot that it loses in its gradual descent earthward. It gives one an idea at once of what the engineless air-sailor's problem really is. Launched into the ocean of the""a7r he knows his craft will take him 16 feet forward with a loss of only one foot of height. If, therefore, during this 16-foot movement through the aerial sea he can steer into an uptrend of wind which raises him a foot, he has lost no altitude at all; while, should the gust lift him two feet, then he is a foot to the good at the end oP his 16-foot forward glide. Always falling, very slowly because he is motorless, the air-sailor must go seeking those up-trends of air which will not only check this inevitable fall, but which will, if they are powerful enough, raise him bodily high above his original starting point. Of course, given a machine witli a finegliding angle, if is all a question of human skill, and more (.'specially, perhaps, of intimate knowledge of the. locality where you happen to be airsailing. The Germans, for instance, know their particular gliding-grounds like the palms of their own hands. They know every slope and ridge, and how the gusts blow over them at certain conditions of the wind.

And it is this fact which, at present, puts a very clear limit upon air-sail-intr. vou must have a locality where the configuration of the earth, influencing the lower wind-flows, is favorable. And, in the second place, vou must learn, by constant gliding, to make the utmost use of these local wind movements. . . Hut what is now done only within a fairly small radius of the startinghill should, with the increases of knowledge which will bring greater confidence, become possible on a wider and wider scale, until, harnessing winds to their aid as do seamen, our ultramodern "sailors" will travel long distances, motorics*, through the intangible ocean of the air.