Evening Post SATURDAY, APRIL 15, 1911. AERIAL NAVIGATION.

Evening Post, Volume LXXXIII, Issue 88, 15 April 1911, Page 4

Evening Post SATURDAY, APRIL 15, 1911. AERIAL NAVIGATION.

There is no more fascinating study to-day than the progress of aerial navigation. The balloon is over a century old, dating back to the last years of Louis XVI., when Montgolfier gave exhibitions before the Court of Versailles. But ballooning is not navigation of the air, any more than the drift of a derelict in ocean currents is the navigation of the sea. The- vertical movement of an ordinary balloon' is to a certain ! degree controlled by jettisoning ballast or releasing gas; but horizontally the balloon is at the mercy of all the winds that blow. Some twenty-five years ago experimenters in France, such as Tissandier, Eenard, and Krebs, altered the shape of the envelope of the ballooa to a cigar form, and by applying what motive power was available then were able to manoeuvre about fairly comfortably in calm weather. Against the least breeze they were powerless. The arrival of the gasoline motor gave a great impulse to aerial navigation in machines lighter than the air. In the 'nineties of the last century many French investigators — for France has always led in the conquest of the air — earned out more or less successful experiments in airships, as navigable balloons came to be called. Santos-Du-mont circled the Eiffel Tower at Paris, and Lebaudy, Severo, and the French military aeronauts built and sailed aircraft — in one or two instances with fatal effects. A few years later Count Zeppelin made Germany's one contribution to aerial navigation with the first of his now famous series of rigid dirigible balloons. These represent the last word in the conquest of air by apparatus lighter than the medium in which it moves. England has lagged behind and slavishi)y copied her neighbours, The BritiiU

war balloons have hitherto been of the non-rigid and semi-rigid type, on the general lines laid down by the French pioneers. They have done as well as the average airship. Some have been wrecked, including Barton's original design and the ill-fated Nulli Secundus, which tore from her moorings in a gale after a promising start. There are one or two left, and occasionally on some fine day they sally forth from Aldershot and execute a peaceful flight over the neighbouring country. Mr. Willows, of Cardiff, has built a workmanlike small airship with which he has flown from Wales to London and from London to the soil of France. The much-talked-of Clement Bayard Daily Mail airship in calm weather sailed from Paris to London, landing at Wormwood Scrubbs. The greatest feat of the Zeppelins has been the flight of one from Friedrichshafen to Berlin, a dis* tance of some 700 miles. The latest news is an announcement that a company has been formed in Berlin with a capital of two millions sterling to construct rigid airships for Transatlantic among other flights. Each vessel is to have a gas capacity of over three million cubic feet, the length being 775 ft. The power equipment will be motors, of from 30 to 100 horse-power — how many is not stated. The airship will be manned by a crew of 100 officers and men, and will be capable of carrying 200 passengers between London and New York. Such is a summary of the cable message. Let us consider briefly in the light of recorded experience with airships what possible prospect of success this extraordinary enterprise can have. In the first place, no airship, whether rigid or non-rigid, has ever proved itself capable of meeting and fighting a_ gale. All voyages hitherto have been in practically calm, weather, or, where there ha 1 , been wind, with favouring winds. The North Atlantic is one* of the stormiest regions of the world. What hope would the great bulk of an airship, as big as an Atlantic liner, have in an ordinary gale, not to mention a storm ? All past experience goes to show it would simply drift with the wind. Even if the captain of the airship elected to fight, his petrol supply would bo limited, and a day of hard battling with the gale would find it pretty nearly exhausted without much, if any, progress made. The principle may be seen in this. A Zeppelin airsnip is credited with a speed in calm weather of about 35 or, at the outside, 40 miles an hour. If the wind is blowing ahead 40 miles an hour, how can the airship possibly gel along? But suppose the weather remains fine for a whole week and the airship has an ample supply of petrol to cover the Transatlantic air-ferry in that time, would it not succeed? The prospects are again unfavourable. During the day, when the air is warm and the sun shining, the hydrogen in the envelope expands very considerably, tending to raise the balloon to great altitudes. It is likely, too, that a. certain amount of gas will escape owing to the increased pressure from expansion. At night the atmosphere becomes much colder after the sun is set. The, hydrogen in the balloon contracts again and the whole airship sinks. If there has been any escape of gas, as is extremely probable, she will descend lower than her average altitude the previous night. And go on night after night the same process recurs. This has always been the trouble with long balloon voyages. It was this phenomenon, or rather his attempt to cope with it, i that brought Wellman's Transatlantic air-voyag& in the "America" to an untimely close last year. There are a multitude of minor difficulties with airships^ — difficulties of landing and launching with their huge, fragile bodies. Zeppelin has met with disaster after disaster through similar causes. It seems to us that the conquest of the air lies not with the airship, but with the aeroplane. Everything goes to show this. Birds, the best exponents of flight we yet have, are heavier than the air, otherwise they could not fly. Then compare the resistance offered to the air by the respective machines of the lighter than the air and the heavier than the air typo. The aeroplane cuts the air with its planes; the airship 'pushes a great bulky body with a blunt nose laboriously through its supporting medium. The aeroplane already travels twice the speed of the airship, and is likely within a very few years to double its speed again. It should then be able to face the strongest of normal gales, blowing, say, at fifty miles an hour. Of course, many improvements will be needed. The aeroplane of the future must be more stable than it is now, both laterally and longitudinally. It may be stability will be secured automatically by a gyroscope. Then some provision must be made for, as it were, shortening lail in the air. An aeroplane at 100 miles an hour requires xess than half the supporting surface it needs at fifty miles. Then structural details must be modified, with a view to greater strength. The present tangle of wood, canvas, and wire must be replaced by an all-metal simplified structure. Here there is room for the discovery of light and strong alloys, 6uch as the duralumin used in the manufacture of the latest British airship— by the way, a Zeppelin— built by Messrs. Vickers, Son, and Maxim, at Barrow. Engines must be made more reliable and more economical of fuel, and with this object in view many engineers are looking towards the twocycle internal combustion engine and the gas turbine. Even now the present is with the aeroplane. Flights have been achieved across country over distances of 300 miles, and as many as eleven passengers have been carried on one machine. It seems, then, the future will be to the aeroplane and the aviator. Not only will the aeroplane be widely used for military purposes, but it will be a sort of motor-car oi the air, carrying passengers, mails, small parcels, with extremely rapid transit, over long distances. It i 6i 6 not likely that aeroplanes .will ever carry 200 passengers, as the Berlin airship promises to d<^- J ll^ VrillV rill be leffc to airships still, mm will be jrast* rowttk fair-weather;

cruisers, moving slowly (as compared with aeroplanes) over the countryside, and pleasantly affording to the sensationseeker of to-morrow the thrills of tho bird's-eye view from the comfortable armchair.