LIGHTER THAN AIR

Dominion, Volume 11, Issue 309, 24 September 1918, Page 6

LIGHTER THAN AIR

WHERE THE AIRSHIP BEATS THE AEROPLANE

PATROL-SHIPS AND KITES (By Air Mechanic.) Airships in their extreme known, form—the Zeppelin—are somewhat discredited as instruments of offence by the exporicne of this war. The lighter-than-air type of aircraft has certain, advantages "over the hcavier-than-air typo which may or may not bring an. improved form of Zeppelin into use iu, tlic coming era of commercial aviationGranted that it is unwieldy—the Zen- 1 polins vary from 520 to 775 feet in length—the airship has two great scores over the (Aeroplane —lift and duration power in the air. The weight of the aeroplane itself uses up 50 per eent. of the total lift, and the weightof crew and accessories require another 25 per cent., leaving only 25 per cent, for cargo, which, in war, mean* bombs, machine-guns, spare petrol, wireless, etc. The Zeppelin has good; lifting powers; it is lighter than air and rises naturally. It is capable of carrying' a weight of 20 to 23 tons. The aeroplane can carry only a limited supply of petrol, and its duration power la rarely more than six hours. That of tho Zeppelin is perhaps five times as much. These aro points which favour the Zeppelin. But it is.mora at tho mercy of adverse weather than.' the aeroplane, is very costly, and requires a colossal shed to house it. . Tho Zeppelin as an offensive engine )in this war has proved not worth the candle. . But that is not to say that the argument of lighter-thau-air versus heavier-than-air has gone finally against the airship, even in war. On the contrary, the small airship is most valuable as a naval scout in spotting "tip and run" German destroyers or submarines. It cannot by reason of its size and consequently limited duration capacity carry out patrols at a great distance from ' its base. It patrols, above ' the routes 'of the outgoing • submarines over which it can fly and (unlike tho seaplane) can' stop if jthe submarine stops. It can drop bombs effectively on a submarine at or near the surface; it can sink deep-level charges at a submerged submarine, aud it can report by wireless. . The captive observation balloon is a, development of the lighter-thau-air type—ugly shape, head down in the air, like a bull-moose about to charge. The traditional spherical balloon has played its part in other wars, but for modern observation purposes the round balloon-rolls in the wind too much to make accurate observing possible. A gas-bag, a car, a steering-bag to keep the whole'.head-on to the wind, 'and a tail of parachutes acting as a wind-anchor, are • the features of the observation kite-balloon which is _ attached by steel cable, to a steam-wiiieh below, and connected by telephone with the battery for which ite observers are "spotting." Kite-balloons arc, of course, in capable of repelling an attack by enemy aeroplane, but the aeroplane has first to get over them,-which, seeing that they ' are behind ,the British lines, is not the easiest place for a German aeroplane to reach. If a. German aeroplane gets uncomfortably near, the observers can either stay in the car and have the balloon hauled down to earth or they can take to the parachutes. '' Observers do not parachute for pleasure. There is tho first drop, like a stone for 50 or 60 feet, with the horrible doubt if the parachute will open properly, and the long strain of the subsequent descent. The sneed, "after the first rush, is about 4ft. 9in. ner second. A drop of 5000 feet would take the parachutist over a quarter of an hour. The parachute is n, means of escape. It follows that when the Germans record, as thev sometimes do. the destruction of a British kiteballoon, its inmates have by no means shared the fate of their craft. .For such apparently vulnerable taraets, kite-balloons are. as a matter of fact, extraordinarily difficult to destroy.