BRITAIN'S SCOUTING AIRSHIPS

Dominion, Volume 9, Issue 2851, 16 August 1916, Page 6

BRITAIN'S SCOUTING AIRSHIPS

NEW TYPE OF DIRIGIBLE.

The new British aerial construction programme for 1915-17 is said to comprise the laying down of 50 airships of 'both tho rigid and non-rigid types, the construction to be completed within two years. The airships are comparatively small craft, and their range is naturally a limited one. .They are, however, capable of a great speed whioh. makes them particularly desirable for scouting. A unique feature of this dirigible is. its car, whioh ■ is constituted by an ordinary fuselage of a British army, aeroplane, complete with its engine, tractor air-screw, and landing gear, cxcept for the wheels. This_ disposition, is very commendable, particularly for small airships, as. it advantageously does away with the heavy car, whioh, ■ with its elaborato engine mounting and. propeller transmission, greatly reduces the useful load and also creates much head resist-

y anco, harmful to the vessel's speed. In the latter respect the design of this airship seems remarkably efficient/ \ head resistance being cut down to the i, possible minimum, there being, in fact, buu two stream-lined bodies (envelope - ond fuselage), connected .by a simple suspension. The excellence of this do's: sign also accounts for the relatively small-power plant, which is constituted • by a 70-horee power, water-cooled Renp nult engine,, driving a tractor screw. ..- Tho speed airships of this class develop ,is not officially disclosed, but seems to bo m the neighbourhood of ,40 miles por hour, rather more than less. An interesting feature that is entirely novel and shows a: persistent thought of simplifying' the mechanical devices of this. airship, is found in ■ the air-blower, which compensates on »on-rigid airships, such losses of buoy- ... ancy that' may occur through variap tions ■ of- temperature and barometric '■ pressure. -■ Instead of using an ordinary - air-blower actuated by tho engine, the- ... designers of this airship utiliso the "slip-stream" of the propeller—-i.e., the' air thrown back by the latter. For this purpose the envelope's "neck," through which air may be pumped into the com- • pensating ballonet, lias its aperture /- placed right behind the propeller, the amount of air admitted into the ballonet being regulated by a valve. Besides its great simplicity, this arrange•V ment strongly commends itself on account of the amount and driving power . . i . of tho air that thus becomes available ; for compensating losses of buoyancy in the_ gas bag of the airship. Although their work has been less spectacular than the operations of German Zeppelins, the non-rigid and semi-rigid air- , ships of Great Britain and France have proven very useful for night raids on enemy encampments, and, in connection ■ With naval warfare, the harbour de- - fence, and coast patrol work. Accord- ; ing to the "Echo de Paris," the mobile forces of every French naval port now comprise, in addition to destroyers and i: submarines, two small non-rigid air-

ships. These are chiefly used for de- ■ tecting enemy submarines, ancT are said 1 to have given an excellent account of themselves. —"Scientific American."