Aerial Navigation

New Zealand Tablet, 9 July 1908, Page 30

Aerial Navigation

A cable message from Berne in Saturday's papers stated that Count Zeppelin, in his aerial warship, with a dozen passengers, made a 12 hours' flight at a great height, from Lake Constance to Zurich and Lucerne and back, at a speed of 30 miles an hour. In connection with Count Zeppelin's successful flight it is interesting to note the opinions of the inventor of the Maxim gun, Sir Hiram Maxim, who says that before a successful flying machine is perfected many difficulties will have to be surmounted. I have been carrying out extensive experiments with aeroplanes (he says), and have experienced that, in order to give a balloon sufficient lifting power to carry two men and a powerful engine, it is necessary it should be of enormous bulk. Therefore, not only is a very large surface exposed to the wind, but the whole thihg is so extremely light and fragile as to be completely at the mercy of the wind and weather.

Take that triumph of engineering skill, the Nulli Securidus", for example. The gas-Wg, which was sausage-shaped and 30ft in diameter, was a beautiful piece of workmanship, the whole being built up of gold-beater's skin, at an enormous cost. The whole construction, including the car, the system of suspension, the engines and propellers, had been well thought out, and the work fully executed.; yet. still, under these most favorable conditions, only a slight shower of rain was necessary to neutralise its lifting power.

The new airship to be produced by the War Offico is said by the designers to remove this difficulty. It is being constructed with a greater capacity and a stronger engine. The gas-body of the new balloon is to be sausage-shaped and 42ft in diameter ; the area of the cross-section would, therefore, be 1385 square feet. The designers state that it is to be provided with an engine of 100 h.p., which it is claimed will give it a speed of forty miles an hour through the air, so that with a wind of • twenty miles an hour it will still De able to travel by land twenty miles an hour against the wind.

This speed, however, is proved on scientific grounds to be practically impossible with such a vessel. If the new balloon were attached to a long steel wire and drawn by a locomotive through the air, the amount of energy required would be 236' h.p. — that is, if the gas-bag would stand being driven through the air at the rate of forty miles an hour, which is extremely doubtful. Under these conditions, the driving wheels of the locomotive would not slip, and therefore no waste of power would result.

But in the dirigible balloon we have a totally different state of affairs. The propelling screws are very small in proportion to the airship, and their slip is fully 50 per cent. — that is, in order to drive a ship at the rate of forty miles an hour the screws would have to travel at least eighty miles an hour. It would, therefore, require 472 h.p. instead of 100 h.p. to drive the proposed new vessel through the air at the rate of forty miles an hour. It will be seen from this calculation that the new airship will still be at the mercy of the wind and weather.

The experiments of navigating the air with machines heavier than air — the only true flying-machine — have proved that the 'difficulties are not nearly so great as^ is generally supposed. In 'an aeroplane it is possible to get a much stronger build of .machine, besides greater speed, than in the case of airships.