■MO 



I)IS(;ovi:hy 



previously in lightness, reliability, and economy in 

 fuel ronsiimption— all attributes of extreme importance 

 for civil work. The net result of the alliance of this 

 eni^ne with the greatly improved aeroplanes which 

 were designed with a view to the special requirements 

 of transport work is that the present-day single- 

 engincd 450 h.p. machine carries eight, and in some 

 cases ten, passengers ; while the twin-engined type, 

 with 900 h.p., has seats provided for 16 to 20 passen- 

 gers, which is a great improvement on the capabilities 

 of the converted war machines just referred to. These 

 figures, showing that the commercial load-carrying 

 capacity of singlc-engined machines has been 

 quadrupled with an increase in engine-power of only 

 20 per cent., demonstrate perhaps more clearly than 

 anything else the strides that have been made in 

 commercial aeroplane design since the Armistice. 



Details of some representative tv'pes of modem 

 British passenger and mail carrjang machines may 

 prove interesting. To take the large two-engined 



KlG. 2.— THli H.\NDI,UY-1>.\GI-; WING. 

 An experimental application to show the principle. 



aeroplane first, the Handley-Page " W.8 " type, which 

 will shortly replace the converted war-bomber " O.400 " 

 type in this firm's London-Paris service, has seating 

 accommodation for 15 passengers and is driven by two 

 450 h.p. Napier " Lion " engines. It has a full speed 

 of 115 miles per hour, enabling it to maintain an average 

 over the ground of 85 miles per hour. The saloon is a 

 very comfortable compartment with no obstructions in 

 the way of struts or wires, fitted with arm-chairs, beside 

 each of which is a round glass window providing an 

 excellent view. The two pilots sit in a small cockpit 

 in the nose of the machine, so that they have a free 

 outlook in every direction, and immediately behind 

 them is a luggage compartment in which each passenger 

 is allowed to take a certain amount of luggage free. 

 This machine is notable for the way in which, in spite of 

 its large size, it gets off the ground, and the steep angle 

 at which it climbs out of the aerodrome. The same 

 firm arc making strong efforts to increase the weight- 



carr\'ing capacity of all aeroplanes by introducing ;i 

 patent wing which it is hoped will provide an increase 

 of about 20 per cent, in the commercial load which can \m- 

 carried with any given horse-power. This patent, 

 which is still the subject of experiment, consists 

 essentially in forming each main plane of the aeroplane 

 from a number of long narrow wings with slots Ijctween 

 instead of having one solid wing as at present. An 

 elementary experimental application of the idea, by 

 putting one of these narrow wings in front of an 

 ordinary aeroplane wing, is to be seen in the illustra- 

 tion on this page. 



In some ways the most interesting, as it is the latest 

 in design, of modem British machines is the De Havil- 

 land 29 Monoplane seen in the first illustration. It is 

 perhaps not unfair to Captain De Havilland, the 

 designer, to say that this machine shows traces of close 

 study of German trend in design in the sense that it is 

 of the cantilever-type method of wing construction 

 originally introduced in Germany. This system has the 

 advantage of eliminating all extemal bracing wires for 

 the wings, which leads to simplicity : it has a neat 

 appearance, and probably it adds four or five miles an 

 hour at least to the speed by reducing the resistance. The 

 two pilots' seats are well placed on the top of the 

 fuselage just at the leading edge of the wing, while the 

 luggage compartment is at their feet behind the 450 h.p. 

 Napier " Lion " engine. The passenger saloon, which, 

 unfortunately, is hidden by the wing in the illustration, 

 is filled with bucket-scats and has long windows along 

 each side. A noteworthy feature is the provision of an 

 emergency exit in the roof as well as considerable door- 

 space in the sides, which give ample chance for escape in 

 event of a bad landing. The tail planes as well as the 

 main wing are entirely self-supporting without extemal 

 bracing, and the control cables are led direct without 

 passing through any fairleads or pulleys to avoid the 

 constant renewals which the friction from such guides 

 entails. Another interesting feature is that the engine 

 is easily removable as a separate unit with all its 

 accessories such as carburettore, magnetos, etc. — a most 

 important factor from the point of view of mnning 

 costs, as an engine can be changed and the machine 

 continue in service instead of its being out of com- 

 mission while engine repairs are being carried out. The 

 undcr-carriage is removable, with the same object. This 

 machine is altogether a very remarkable production, 

 as it carries, with one 450 h.p. engine, no less than 

 tweh-e persons — two pilots and ten passengers — and 

 500 lb. of luggage a distance of 450 miles without land- 

 ing. The top speed is 130 miles an hour, and with the 

 engine running at only a little over half-power the speed 

 is still 100 miles an hour. Generally speaking, it may 

 ahnost be said that the Safety and Economy Report of 

 the Roval Aeronautical Society referred to above 



