SCIENCE AND TOPICS.

Bay of Plenty Times, Volume LIX, Issue 10615, 13 July 1931, Page 2

SCIENCE AND TOPICS.

LET'S GLIDE. Soaring on the wings of a motorloss Plane. Gliding has found its niche in aviation. More reasons than the thrill of “riding the wind" in a sailplane account for the boom in gliding. The glider, pioneer of the airplane, is the training ship for young pilots. It is used by scientists for making aerodynamic tests. Few people who have not seen gliders in action have any conception of what they can do. The technique of gliding has advanced a very long way since enthusiasts jumped off from hilltops and steadied the plane by dangling their legs from side to side as they drifted down. Gliders may be launched now from airships to spiral to the ground. One expert has kept a glider continuously in the air for 14 hours 4 3 minutes. Another has travelled over one hundred miles across country.

How can a motorless plane remain so long in the air? The problem seems even more difficult when you realise that a glider may actually land on ground that is higher than the land from which it was launched.

One joy of gliding is the designing of a glider. The ideal would be for every enthusiast to construct for himself the featherweight craft in which he makes his first attempts. A simple glider has four removable sections, the wings, the rudder section, the tail section, and the main skid section. Motor gliders are also used; their engines are the “babes” of aviation. Experiments are continuously being made; one glider is tailless, having no rear fuselage. Gliders are launched into the air by rubber cables, for all the world like a giant catapult.

Two or three men hold the tail of the machine while the launching team run forward. On the word to realease, the men at the tail let go, and the glider is hurled into the air.

The skill and sport of gliding consists iii keeping the machine up by taking advantage of the up-cur-rents of air. That is why gliding is magnificicnt training for a newcomer to aviation. You need “air sense” to cheat the force of gravity in your motorless machine. Hilly and mountainous country •is more suitable for gliding than flat, low-lying land. Air is filled with up and down currents. When a breeze strikes a hill, tor example, it is deflected upwards. forming a lifting column of air. When the glider enters this, it is lifted faster than it descends. Finding air currents, and taking advantage of them, is the secret of gliding. The longest cros-country flight was made by a glider riding in front of a thunderstorm. He rose to a great height, and touched seventy miles an hour. Then, soaked to the skin, he came down.

A beginner does not ride the wind in this way, for his primary glider is not a sailplane. In England, the Royal Aero Club issues three gliding certificates. To earn the first, the candidate must have carried out a flight of 3 0 seconds, followed by a good landing. Before attempting to qualify, he must have made twelve glides at least —which usually will be existing hops, rather than glides, down the side of the hill where his gliding club gathers. The second gliding certificate is awarded for a flight of one minute, with two curves in the form of an “S.”

. „. f „ f - height greater than the point of de- : p A similiar series of tests faces German aspirants for gliding fame, : So the enthusiast approaches the day when he will join with the mas- . ters of this art, and soar above the : hills, woods, and sea for mile after mile, spiralling in the sky, without a sound to disturb him save the rustle of the wind on the wings of his plane.

Certificate C goes to the candid date who has carried out a flight of not less than five minutes at a

During the last year or two the progress of gliding has been remarkable. Its greatest vogue is in Germany, Britain, the United States, and Australia.

Sailplaning, as distinct from gliding, combines the use of verr.ical air-currents met with over certain landscapes and tlie currents found under cumulous clouds. “Cloud soaring” calls for the use of the currents set up by the clouds.

"One problem has yet to be solved—how to keep the glider in the air over landscapes where favourable currents are not to be found. It is believed that this problem will eventually be solved.