Gloster VI

Проектирование гоночного гидросамолета Gloster V было прекращено, и лишь в начале 1928 года Генри Фолланд и его конструкторы приступили к разработке новой машины, отказавшись от схемы биплана в пользу моноплана. Самолет должен был участвовать в гонках на кубок ДальшеMore>>> Шнейдера 1929 года. Выполненный по схеме низкоплана, Gloster VI имел подкрепленное расчалками крыло и свободнонесущее оперение деревянной конструкции, а фюзеляж и поплавки были выполнены из легких сплавов. Почти вся поверхность крыла была занята радиаторами двигателя Lion VIID, а маслорадиаторы размещались по бортам фюзеляжа, за кабиной. Кроме того, дополнительные маслорадиаторы были установлены на верхней поверхности поплавков.
   Построили два Gloster VI, но испытания в Кэлшуте в августе 1929 года показали, что форсированный Lion VIID быстро перегревается, и самолеты сняли с состязаний. Они закончили свои дни на базе ВВС в Феликстоу, причем все попытки решить проблемы с двигателем не дали результатов.


ТАКТИКО-ТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ

   Gloster VI

   Тип: одноместный гоночный самолет
   Силовая установка: один W-образный поршневой двигатель Napier Lion VIID мощностью 1320 л. с. (984 кВт)
   Летные характеристики: макс. скорость на высоте 30 м - 565 км/ч
   Масса: пустого 1036 кг; максимальная взлетная 1669 кг
   Размеры: размах крыла 7,92 м; длина 8,23 м; высота 3,29 м; площадь крыла 9,85 м!

Flight, August 1929

THE BRITISH SCHNEIDER TROPHY DEFENDERS

   ITS arrival impatiently awaited by service and press alike, the Gloster VI racer, with Napier VII D racing engine, was brought from Cheltenham to Calshot on Saturday of last week, and erected without loss of time. Representatives of the press were permitted to see the machine on Sunday, and to say that they were impressed is to put it mildly. When the hangar doors were opened and the machine wheeled out it was seen that the Gloster-Napier VI is a very diminutive monoplane, streamlined with the most extreme care, and finished in a peculiar matt-brass colour which, although admittedly not making the machine fly any faster, certainly increases the impression of "daintiness," which perhaps best characterises this year's Gloster Schneider defender. Actual dimensions may not be given, but the Gloster-Napier VI appears, as regards its fuselage, even smaller than the 1927 Supermarine S.5. Just how far this is actually the case, or whether it is due to the effect of lines and colouring, is difficult to say. But that an engine of the power of the Napier VII D, and a pilot of average size, could be got into a smaller compass is difficult to imagine. It is also worth noting that for this year's contest Mr. Folland has adopted the monoplane arrangement.
   No figures may be published concerning the power developed by this year's Napier racing engine, but it is probably no secret that its power is considerably greater than the power of the 1927 Napier racing engines. On the other hand, the power is certainly not as great as that of the Rolls-Royce K engines fitted in the Supermarine S.6 monoplanes. This the Schneider contest will have added interest from the fact that the two British types of machine produced for this year's contest differ quite a good deal, in spite of their generally similar appearance. Both are low-wing monoplanes, with streamline wire bracing. But the S.6 has a more powerful and heavier engine, which at once means a slightly larger machine to carry the extra weight of engine and the weight of the extra fuel which the more powerful engine will consume in covering the Schneider course. There probably is definite limit in power for a single-engined type beyond which it does not pay to go, because the machine size, after a certain point, increases in proportion. Whether the Supermarine-Rolls-Royce S.6 or the Gloster-Napier VI provides the best combination of power and size remains to be seen. It is quite possible that flight tests will indicate that there is very little to choose between them in the matter of speed.
   In the design of the two types of machine the Gloster-Napier VI differs from the Supermarine-Rolls-Royce S.6 in two main respects, apart from the matter of size: The wings are attached to roots on the fuselage placed some distance out on the oval section, whereas in the S.6 the attachment is almost on the bottom centre-line. Consequently the float struts on the Gloster machine do not "meet at a point" as in the S.6, but enter the fuselage at points some 2 ft. apart. This may appear a very minor point in design, but it should be realised that in designing a racing machine to do, perhaps, something like 350 m.p.h., the. "interference drag" is likely to be a serious consideration, and the problem of how to reduce it is a very important one. The Gloster monoplane wing differs from that of the Supermarine S.6 in that in plan form the maximum chord occurs not at the root but a considerable distance outboard, at the point where the bracing wires are attached. The maximum wing thickness occurs at the same point, the aerofoil section tapering in thickness from there to root and tip. Other differences in the aerodynamic design of the two machines are connected chiefly with the fuselage streamlining, the "broad arrow" arrangement of the Napier engine requiring a type of cowling rather different from that of the Vee type Rolls-Royce engine.

Constructional Features

   In the matter of construction, Mr. Folland has used, in the Gloster-Napier VI, a "mixed" form, the fuselage and floats being built of duralumin, while the wings are of wood. The fuselage is of the monocoque type, with light formers of duralumin, and a skin or plating of duralumin sheet. All rivet heads are sunk in flush with the skin so as to reduce friction drag by leaving a quite smooth surface. The thickness of the skin is graded from nose to stern. In cross-section the fuselage is the smallest that will contain the engine and pilot, and the planning of the lay-out of controls, piping, &c, to come within such a small compass must have presented a pretty problem.
   The monoplane wings, as already mentioned, are of all-wood construction, with multiple spars (6) and a planking of spruce, laid on in two plies, one diagonally. This planking is made up on a former of the same contour and curvature as the actual wing, and when the waterproof glue is dry, the planking is removed and transferred to the wing, and there secured to the spars and leading and trailing edges with screws. All the main lift wire fittings are of high-tensile steel, and completely housed inside the wings, only the streamline wire protruding.
   The duralumin floats are of usual Gloster design and construction, with straight top and vee bottom, a single step and a vertical stern post. Each float has a single, deep, fore and aft member or keelson, and a number of transverse frames spaced some 18 in. apart. The float bottom is reinforced with "Z"-section stiffeners, and the deck with L-section stringers. In the floats, as in the fuselage, flush-head riveting is employed to give a smooth surface. Three watertight bulkheads are employed in each float so as to reduce the risk of sinking in case of damage to one compartment.
   In constructional detail principle the tail of the Gloster-Napier VI is similar to the wing, being of all-wood construction. The covering is, however, in the form of multi-ply wood. The angle of incidence of the tail plane can be adjusted from the ground, but not in flight.
   In connection with the controls, it is almost superfluous to state that there are no external levers or cranks, all being housed inside either the wing or fuselage. A form of variable gearing has been incorporated in all the controls in such a manner that the control surfaces are "geared down" in relation to stick and foot bar for small initial movements, and "geared up" for larger movements. The object of this variable gearing is, of course, to make the controls light and effective both at high and low speeds. It may be stated that for the initial movement the gear ratio is approximately as 3 to 2; while for the last few degrees of possible movement the ratio has changed roughly to 2 to 3.

Cooling Systems

   Ever one of the most difficult problems in the design of a racing machine, the water and oil cooling systems in the Gloster-Napier VI show some unusual features. Unfortunately, it is not permissible to go into any great detail, beyond stating that as in all racing seaplanes of recent years the water radiators are of the wing-surface type, consisting of flattened tubes laid side by side and sweated together, the tubes running in a fore and aft direction, and being joined at their ends, i.e., at leading and trailing edges, by collectors running at right angles to them. As the total wing area of the machine is so small, nearly the whole of it is covered with radiators. The exception is a narrow belt in the region of the bracing wire attachments, and the extreme wing tips.
   The oil cooling system is somewhat similar in principle, but the radiator portion is formed by a ring of flat tubes surrounding the fuselage just abaft of the cockpit, and the oil tank is carried just behind the pilot. The surface of the oil cooler is let in flush with the fuselage covering, and follows the contour thereof. Additional oil cooler area is provided on the decks of the two floats.

Petrol System

   In previous Gloster racing seaplanes the fuel has been carried in the fuselage. The reduction in cross-sectional area which has taken place in this year's machine has made this arrangement impracticable, and the system of carrying the fuel in the floats has been adopted instead, the fuel being equally divided between the two floats, and a service tank of small capacity (about 2 gallons) being placed in the fuselage. Two fuel pumps transfer the petrol from the float tanks to the service tank, and a special arrangement ensures that the amount of petrol taken from each float tank shall be the same.
   The propeller used in the Gloster-Napier VI is of “Gloster” design and construction, and is made from a solid forging milled on a special machine to ensure correct contour and pitch of the blades. No twisting of the blade is necessary.
   For obvious reasons, no speed figures can be givenm but it is claimed for the Gloster-Napier VI that, although a pure speed machine designed to operate at sea level, it has an initial rate of climb of nearly "a mile a minute." Converted into more customary climb figures, this represents a sea level rate of climb of approximately 5,200 ft./min., which is probably more than twice the rate of climb obtained by any other type of aircraft!

The Napier "Lion," Type VII D

   The engine produced by the Napier firm for two of this year's Schneider Contest machines is a development of the 1925 700-h.p., and 1927 900-h.p. models. The new engine develops a great deal more power than did the 1927 type. How much more may not be stated, nor the manner in which the extra power has been obtained. It is, however, permissible to mention that a supercharger has been incorporated, so mounted on the rear end of the engine as not to increase the frontal area, nor to cause protuberances of any kind. One of our photographs shows the new engine, and the small size and generally "clean" appearance are noticeable. Actually the frontal area has been slightly reduced in spite of the extra power, and this fact has helped materially in enabling Mr. Folland to design such a tiny and clean machine around the Lion VII D. It should also be mentioned that the air compressor has been designed by the Napier firm, with the cordial co-operation of the British Thomson-Houston Co., Ltd., of Rugby, and the Bristol Aeroplane Co., Ltd., of Filton, Bristol.
   The latest type of "Lion" is a triumph of engine design, while retaining the "broad arrow" formation of its cylinder arrangement, and Capt. G. S. Wilkinson, F.R.Ae.S., M.I. Mech.L, M.I.A.E., deserves every credit for the manner in which he has developed these racing engines from the original “Lion."