FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1942
1942 - 0598.PDF
With the wing resting on the hull, as in the Saro Cloud above, the engines have to be raised on " stilts." In the Handley Page Heyford (right) both engines and fuselage were raised to the level of the top plane, an arrangement dictated by military rather than aerodynamic considerations. the Martinsydes. The large fiat surface of the radiator immediately "behind the airscrew did not improve the effi ciency, and as a next step the radiator was removed from the nose, which was made pore pointed, and placed inside the fuselage and so arranged that it could be raised and lowered through the bottom. That was an improvement in that the amount of cooling could be varied to suit conditions. But the area required was still large, and a reduction was sought by adopting part steam-cooling. There were objections to this, and through several stages we arrived at the glycol-cooling now used, the chief pur pose of the glycol mixture being to avoid freezing. Hitherto we have dealt with single-engined aircraft only, and have outlined the steps by which the modern single- engined tractor arrangement has been evolved. The sub stitution of variable-pitch airscrews for the old wooden airscrews is part of the story, but does not directly affect engine placing. Now let ns examine the development of the multi-engined types. From the fact that the early experimenters were always troubled by lack of power it might be expected that it would soon occur to them to fit two or more engines. This seems an obvious step nowadays, but it must be remembered that simplicity had to be the keynote of design in the beginning. The engines in those days were very unreliable, and the installation difficulties with two engines deterred many designers from taking that appa rently easy way. Even in more recent times we have heard the view expressed that the second engine was more trouble than it was worth. The late Harry Hawker, who flew the Atlantic on a single-engined aircraft in 1919, said, ft J ' MARCH IQTH, 1942 The first taniem-enginel machine was the Short, shown on the left. It appeared in 1911 and had two Gnome rotary engines, with the pilot seated between them. The tandem arrangement of liquid-cooled engines was particularly favoured for flying boats by Dr. Claude Dornier. Airscrew clearance was provided by making the wing a pacasol. The machine shown above is one of the " Wal " type. when we asked him why he did not select a twin-engined type, " There are merely twice as many chances of engine failure " ! But there were designers who, even in the very early days of flying, did not shy at the troubles of a second engine. The late Horace Short was one of them. To him must go the credit of producing the first twin-engined air craft. It had two Gnome rotary engines, one in front^^ of and one behind the pilot; -otherwise it conformed to'*' "* the usual early pusher type. This machine had direct . drive for both airscrews, but other versions had direct drive to one and chain drive to two airscrews. The most "refined" of them had an ordinary tractor, fuselage, the front engine being in the normal position in the nose, and the second being housed inside the fuselage, with chain transmission to two airscrews mounted in the wings. Early Wing Engines The beginnings of "modernity" in twin-engined arrangements may be said to have been such early biplanes as the Handley-Page O/400 and the D.H.3. Both had the .engines located outboard from the fuselage, but whereas the Handley-Page biplane had tractor engines, the D.H.3 had pusher airscrews, with shaft drives. Flyi©;' boats, too, were being fitted with two outboard engines, usually mounted fairly high in the wing gap in order to give the airscrews as much clearance as possible. While on the subject of flying boats it may be recalled that we have in use at the present time one with single pusher airscrew: the Vickers-Supermarine Walrus. This . amphibian flying boat has the only engine arrangement
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
