AIR SAILING.

Waipa Post, Volume XXI, Issue 1339, 9 January 1923, Page 6

AIR SAILING.

GERMANY LEARNS FROM US. A LOST LEAD. (By an Aviation Correspondent.) Motorless aeroplanes are like political promises—a means to an end. The end is to reduce the engine-power necessary to keep an aeroplane in the air. This means less petrol consumption, and consequently cheaper, flying. Anyone who knows anything of the cost of petrol in this country will understand why the gliders should have a special interest for Australia. Gliding is one of the oldest and yet the newest form of aviation. It preceded the present engine-drawn aeroplane, and was then discarded as a thing which had served its turn. Germany has willed that it shall he born again. The reason for this is that, in their wisdom, the Allied Powers decided that the horse-power of German aeroplanes should be so limited that she would never be able to build up a dangerous air force. Germany's reply has been to return to experiments with gliders with the object of producing efficient aeroplanes which require engines of very small horsepower. Experts agree that they are on the way to perfecting machines which will fly with an engine of 10 to 20 horse-power—roughly 100 horsepower less than the average aeroplane in Australia. They have achieved remarkable success with the gliders, one student actually managing to climb to a spot 1000 feet higher than that from svhich he fetarted. The British are close up to them in the new flying, the French are anxiously trailing a long way behind, and Australia is doing practically nothing at all. Yet Australia is the home of the felider. and it is highly probable that the Germans have gained their lead by studying the very gliders which Lawrence Hargrave made 'in Sydney. They have got the best of them there, because Australia didn't think they were worth the room they would occupy. A few models are still in Sydney, holding pride of place in the Technological Museum, but forgotten, or unknown, by people who still think first of Wilbur Wright when they think of the beginnings of modern flying. The things that Hargrave conceived in Sydney the Wright brothers Hew in America. Germany showed a keen interest in Hargrave's work, and sent representatives to Sydney to attend to the shipment of his models to Germany after they had been declined by the Australian authorities.

Strangely, Hargrave, who was so many years ahead of his time, brought gliding to a practical pitch only to throw it out of fashion by inventing the engine known as the Gnome. He didn't call it the Gnome, but in the Technological Museum there is a baby engine which is a Gnome in all essentials, and which is the work of Hargrave. That he was the first to bring the rotary aeroengine to perfection there is no possible shadow of doubt. Gliding' as a Sport. There are a few who are anxious to carry on the good work which Hargrave began and to let the name of Australia figure in the gliding achievements of to-day. They are trying to form a Glider Club in Sydney, partly with the object of experimenting and and partly to get some good sport. Because it is a means to an end gliding has severe limitations. At present they are delicate little things which bestow their favours only on special occasions. They require to be carried to the hills and let loose in a fairly strong wind. Without these two conditions they are helpless. When a wind strikes a hill it shoots up into the sky. The height to which it goes depends upon several conditions. Two primary ones are the strength of the wind and the size of the hill. A glider is heavier than air, but its wings and general shape oause }t to become actually lighter than a rising wind, and by staying in this wind it can rise to a height of a thousand feet or so, according to conditions. The essential is to get into that rising wind. To do this the glider is launched from one hill in a fair wind. The pilot, holds its nose downward for speed, and directs it toward the current of air which, having been blocked by another hill, is rising toward the sky. His task then is to take full advantage of that wind. To do this he keeps turning the machine round, jn long circles, much like a bird circling round one spot. His glider cannot remain still in the air or hover. It remains in the air by virtue of maintaining a certain speed. A bicycle is similarly limited. Unless a certain speed is maintained it cannot keep its balance and topples over. To keep up this speed the pilot must make his machine swoop down toward 'the earth every now and then. He finishes his swoop in the current of rising air. By diving he has attained extra speed. When he reaches the rising air he pulls the machine up. The wind Chen helps him to rise. Each time he rises a little higher until the required height is reached.

Then he can glide about, gradually coming downward. The whole effort of achieving height is very similar to a switchback movement. The faster you come down one hill on a bicycle the higher you can climb the next before you have to pedal again. With the glider the speed of the downward rush is assisted by the rising wind when the pilot pulls the nose of the glider upward. That is the oimple principle of gliding. Every man who has travelledd by air knows something of this fickleness. He has felt what the pilot describes as " bumps." When they are felt the machine is sometimes kicked over on one side, lifted up bodily, or, through striking a pocket of very thin air or a downward rush of wind, drops sometimes several hundred feet. Generally speaking, the ordinary aeroplane, dragged along by a powerful engine, cuts its way through 'these currents without much consideration. But when the engine is cut off, and the aeroplane becomes simply a glider, then tbese eccentricities of a jealous sky are more easily noticed. With the motorless aeroplane they play a big part. The pilot must manoeuvre his machine in accordance with their behaviour. Gli.ling therefore demands skilful piloting, a knowledge of local wind conditions. t <nd a f: : f!i and patience grea'or .>\">.v. Ulan a Job's. But the pilot's rewards are inf-. Up. Pernap.-; for fho fust time in his life he foe's himself a graceful creature. He -3 moving at a mile a

minute, swoop!).-.' and turning with the case of 'i r.sfi-vill, and as noiselessly, The average city man's vision is .-:>.,ly limited. Tah buildings line the stieets on whi-n we spend most of r.ur waking ho.in. and they stretch out endlessly like huge blinkers which harness our eyes ro the front .