AIR LINERS.

Hawera Star, Volume XLVIII, 15 December 1924, Page 8

AIR LINERS.

“GASBAGS” TO'THE FORE. COMMERCIAL AIRSHIP DESIGN. “Gasbags,” as they used to bo sneeriugly called, are very much ill the air at present, literally as well as figuratively, states Flight, the official organ of the Royal Aero Club of the United Kingdom, in a recent issue. This is due to the successful flights across the United States by the American airship “Shenandoah”; to the succesful transAtlantic flight—ssoo miles in a little over three days—accomplished by “Z.R.3” the reparations airship built by the Zeppelin Company for the United States; and to the decision of the British Government to h]jil.d two air-

ships of five million cubic feet capacity, or twice the size of the “Z.R.3.” It should be remembered that the j “Z.R.3.” flight is the third crossing of the Atlantic by an airship, two previous crossings having been gallantly achieved in 1919 by the British rigid airship “R. 34,” in command of Major Scott. “In every respect an inferior ship to the ‘Z.R.3,’” comments Flight, “the ‘R.34’ had the honour of being the first ship to cross ' (and recross) the .Atlantic, and the glory of that famous flight is all the greater when it is realised that the airship on which it was made was not to be compared, as regards efficiency, with the latest ship.” It is anticipated that it will be a matter of three years before the first of the great new British airships can be ready for the trial flight. Dealing with the question of commercial airships, Commander F. L. M. Boothby, designer, in a paper read before the Institution of Aeronautical Engineers, maintains : “It is useless to expect airship-owning firms to start running regular lines till they arG convinced that the aeronautical engineers can provide them with airships that will attract passengers! Airships will not attract passengers till they are safe, and till the fares are low enough to bring them within the means of the average individual. Our commercial airship must fulfil the following requirements : It must be structually strong; (2) it must be safe against fire; (3) it must he controllable in any weather; (4) it must be cheap to run.” As to the first requirement, he says that experience with earlier airships of the “R. 33” type and others has shown that ampler strength can he obtained when half the total displace-

ment is devoted to the hull and. en-

gines. The new commercial Zeppelin, “Z.R.3,”. has this proportion ; and with increase in size, it is fiossible to allot a smaller proportionate weight in the hull and engines while keeping tli,e same strength. For commercial purposes, Commander Boothby’s personal preference lies with the semi-rigid rather than the rigid' type of airship, at any rate for the small sizes, the new Parseval type having been found very efficient. But he adds that the advantages and disadvantages of the two

types are so nicely balanced, that till a. ship of each type, of similar size, and employed on the same service, has been tested over a long period, it will not be possible to reach a decision. “It may be accepted, however, that both types are perfectly capable of running an airship service quite efficcientlv.”

As to safety against fire, he points out that “the first and most pressing need is the abolition of petrol. There are always petrol fumes hanging about in large airships, and in hot climates the evaporation is serious. The most direct and simple wqy, of course, is to fit engines of the heavy-oil Reardmore tvpe_ A second way is to use hydrogen drawn from the gasbags in conjunction witli a heavy fuel in the ordinary engine-; and the third way is t,o gasify crude oil by a new process shortly to he introduced to the public by an inventor, a well-known petroleum expert.” Commander Boothby also shows how the hydrogen may be protected by putting'a. layer of'inert gas around it. “By far the simplest an,d most efficient means appears to be to utilise the exhaust gases for protective purposes. There is an amplei and constant supply of these, which has only to.be cleaned and cooled below boiling point and theni turn into the ring space between the gasbag and the outer cover. The ordinary doped outer cover should be quite gas-tight enough to contain it.” This method has the advantage that the exhaust gases can be first used for cooking purposes and then for warming the living spaces of the airship before being further-cooled and expanded- into the ring space. Commander Boothby also points out how, by simplification of design, it should be possible at once to improve greatly the controlability of the airships and to reduce by about one-half the number of men at'present employed in. airships, thus considerably cutting down the running costs. “What is now wanted,” he says in conclusion, “is some’ process of manufacturing hydrogen witljL the airship’s own resources.. Sitting on the sea there is plenty of hydrogen in the water around, if some reasonably light electrolytic process can'be found. Perhaps some system of cracking oil may meet our requirements, hut it is a point that- requires the earnest consideration of every aeronautical engineer who wishes to see the Empire linked up bv real commercial craft at the earliest possible date.”