Cierva (автожиры X. Сиервы)

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   Следующий (по порядку) аппарат C.30 стал самым известным автожиром, так как серийно производился в нескольких странах. После испытаний модифицированного C.19 MkV со звездообразным мотором Genet Major мощностью 100 л. с. (75 кВт) и с использованием втулки винта, которая могла наклоняться путем наклона ручки управления, фирма "Avro" поручила фирме "National Flying Service" построить двухместную версию с обозначением C.30. В апреле 1933 года ее облетали, и фирма "Avro" получила лицензию на ее производство, присвоив ей обозначение Type 671. Прототип улучшенной модели C.30P с мотором Major мощностью 140л.с.(104кВт) был собран в 1933 году и получил несущий винт со складывающимися лопастями. "Avro" построила три предсерийных экземпляра C.30P и получила лицензию на постройку машин по образцу версии C.30A. 12 машин поставили ВВС Британии с августа 1934 по май 1935 года. 10 из них первоначально служили в Школе содействия армии в Олд-Саруме под строевым обозначением Rota Mk I. Из двух остальных одна прошла испытания на поплавках, а на другой в центре RAE в Фарнборо экспериментально установили мотор Civet Major. Фирма "Avro" построила серию в 66 гражданских C.30A, из них несколько ушло на экспорт, но большинство разошлось в Великобритании. С началом Второй мировой войны 13 из этих машин были мобилизованы на службу в ВВС, в том числе в 529-ю эскадрилью для работы по калибровке РЛС. Несколько машин пережили войну и вернулись к своим гражданским хозяевам, по крайней мере, шесть из них сохранились.
   Аппараты C.30A выпускали и другие европейские страны, включая Францию, где фирма "Liore-et-Olivier" построила 25 машин с обозначением LeO С.301, и Германию, где фирма "Focke-Wulf" собрала около 40 экземпляров.
   Затем появились еще два проекта Сиервы: автожир С.31 1934 года с убирающимся шасси должен был получить двухместную закрытую кабину типа "купе", а подобный ему С.32 создавался в расчете на более высокие летные характеристики. В проекте фирмы "Avro" Type 665 четырехместный фюзеляж биплана Commodore оснащался трехлопастным несущим винтом; его обозначили C.33, но это преобразование так и не закончили.
   Аппарат С.34 1937 года строила по лицензии фирма "Societe Nationale de Constructions Aeronautiques du Sud-Est" со звездообразным мотором Gnome-Rhone 7K мощностью 350 л. с. (261 кВт).
   С.35, С.36 и С.38 остались неизвестными нереализованными проектами. С.37, предложенный фирмой "Avro" под кодом Type 668, был двухмоторным автожиром с кабиной, но его так и не построили. С.39 являлся проектом двух/трехместного морского корректировщика для британской морской авиации. Он должен был иметь трехлопастный несущий винт и V-образный мотор Rolls-Royce Kestrel мощностью 600 л.с. (447 кВт).
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ТАКТИКО-ТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ

   Cierva C.30A

   Тип: двухместный многоцелевой автожир
   Силовая установка: звездообразный поршневой мотор Armstrong Siddeley Genet Major IA мощностью 140 л. с. (104 кВт)
   Летные характеристики: максимальная скорость 177 км/ч на уровне моря; крейсерская скорость 153 км/ч на оптимальной высоте; начальная скороподъемность 213 м/мин; практический потолок 2440 м; дальность полета 459 км
   Масса: пустого автожира 553 кг; максимальная взлетная 816 кг
   Размеры: диаметр несущего винта 11,28 м; длина 6,01 м; высота 3,38 м; площадь, ометаемая винтом 99,89 м1

Flight, November 1933

A NEW AUTOGIRO

   WE recently had the opportunity of being present at a demonstration of the latest product of the Cierva Autogiro Co., Ltd. This machine is the C.30P., which, in its essentials, is the production version of the C.30, that is, the wingless direct-controlled type, but now has the seven-cylinder 140-h.p. Armstrong Siddeley "Genet Major" engine instead of the 105-h.p. five-cylinder "Genet Major." It was naturally expected that the increased power would put up the performance considerably, but we were not prepared for such a large increase as is apparent to those who have followed the "Autogiro" through the various stages of its development. It is not yet possible to publish the performance figures of this new type, and will not be so until an exhaustive series of tests have been carried out with it. As far as can be ascertained, the top speed is in excess of that obtained on the majority of light aeroplanes, powered with this engine; the cruising speed, therefore, should be very comfortably over 100 m.p.h. Senor de la Cierva tells us that the minimum flying speed in still air is between 12 and 15 miles an hour, and his statement was borne out the day we saw the machine flying at Hanworth, as in a wind of about 8 to 10 m.p.h. the pilot was flying across the aerodrome, only a few feet above the ground, at what was very little more than a comfortable trotting speed. Under these conditions his landings were to all intents and purposes vertical, while his take-off was equally astounding. We understand that when there is even only a light breeze it is possible to get clear of the ground in about 5 yards. An outstanding feature of this new model is its stability. In conversation with Mr. J. Ray, the test pilot for the Autogiro interests in America, who is over here with Mr. H. S. Pitcairn, we learned that he had, on his first flight a few days ago, been able to trim the machine so exactly that, although the weather was very bumpy, he flew for over 10 miles without touching the control column at all. This, the first model P, was, as we have already announced, built by Airwork, Ltd., at Heston, and three more of the type are under construction in the shops of A. V. Roe & Co., Ltd., at Manchester.

Flight, June 1934

Cierva Autogiro C. 30 P

   At the Display the latest type of direct-control Autogiro will be demonstrated. This is the type C.30A, fitted with Siddeley "Civet" engine, civilly known as the 140-h.p. 7-cyl. "Genet Major." Most readers of FLIGHT will be aware by now that the Autogiro depends for its lift upon the rotation of its "windmill" blades. These blades are not driven by the engine (except for the initial starting before a flight), but are kept rotating by the air forces upon them. The rotor blades have a diameter of 37 ft.
   The machine to be shown at Hendon has no fixed wing and no tail control surfaces. All manoeuvres, such as rising, descending, and turning, are carried out by tilting the head of the rotor, which has universal joints. The speed range in level flight is from 15 to 115 m.p.h.

Flight,August 1934

ROTATING-WINGED FLIGHT
The Autogiro: Its Construction and Manufacture

   NOW that the C.30 type Autogiro has reached the production stage we are able to publish the first authoritative description of its construction. For many years the name of Senor de la Cierva and his "Autogiro" have been associated in people's minds with a form of flight which was not only radically different from accepted principles, but was also generally understood to be safer because the Autogiro was able to descend almost vertically.
   Until recently, however, the flying machines produced by the Cierva Autogiro Company were rather in the nature of experimental developments of the principle and not, therefore, suitable for quantity production. With the advent of the C.30 type this policy is changed, and A. V. Roe & Co., Ltd., have laid down nearly a hundred machines in their Manchester, workshops.
   As was to be expected, features in conformity with their standard practice have been incorporated by A.V. Roe & Co. so that production could begin with a minimum of delay.
   Like all Avro machines the fuselage is built up of welded steel tubes. The front and rear halves are made up separately, the division being at the bulkhead behind the rear, or pilot's cockpit. In both cases the sides of the fuselage are welded up on flat, table-like jigs, and subsequently the two sides are placed in their correct relation to one another in a vertical jig and the cross struts welded in. In the rear half the diagonal bracing between the two longerons in a horizontal plane is by the Avro method of forming a continuous loop of piano wire by passing it through small curved pieces of steel tube welded into each corner, and joining the ends with a wire strainer. The diagonal bracing in the vertical plane is rigidly built up with tubes. The front half is entirely tube braced. Wherever possible, jigs are used both in order to ensure accuracy and to cheapen production. Consequently there are not only jigs for welding, but also for drilling, as, for example, at the four attachment points where the legs of the rotor pylon join the top longerons.
   After the main part of the fuselage has been erected, the stern post and fins are welded on and the whole is stove-enamelled. The fins, although in reality continuous, may be considered as three in number. The fin on top of the fuselage; the tail fin, which, like the others, is fixed and occupies the same position as the rudder in a normal aeroplane; and the fin underneath the fuselage. All are built up of small-diameter steel tubes welded together.
   The fuselage, from the front of the front cockpit to the tail, is encircled with plywood formers carrying numerous thin spruce stringers running fore and aft and forming a framework over which a doped fabric covering is secured. This fabric is only carried up to the top longerons in the front half of the fuselage, as the decking over the two cockpits is a separate structure of plywood. The engine bay, and the sides and top of the fuselage in the bay behind the fireproof bulkhead, are covered with detachable aluminium panels secured with Avro cowling clips.
   The engine mounting consists of steel tubes bolted to fittings at the ends of the four longerons, carrying at the front a ring which registers with the back plate of the engine. The seven-cylinder Armstrong-Siddeley "Genet Major" engine of 140 h.p. is thereby mounted outside the line of the cowling in a very accessible position, but the drag is kept low by the smooth curve of the cowling behind it. A collector ring with a single downward-facing outlet carries away the exhaust. Fuel is carried in a 23 gall, welded aluminium tank, strapped in position above the top longerons in the bay directly behind the fireproof bulkhead, which is of the normal sheet aluminium and asbestos construction. Mounted on the front of this bulkhead is the oil tank, of 3 gall, capacity, and also of welded aluminium. The throttle controls are the push-and-pull type with duralumin rods.
   Wooden construction is used in the tail plane, which has spindled spruce spars, plywood ribs and spruce strut drag bracing, the whole being covered with doped fabric. This unit is interesting as the camber on the port side is reversed to counteract the engine torque reaction. At each end of the tailplane there are upturned tips of fairly large dimensions which serve to keep the Autogiro on a straight course and also to give it the necessary stability in turns. The trailing edges of these tips and those of the tailplane are in the form of flaps which may be adjusted by means of a small screw for the purpose of trimming the machine.
   A tail wheel is carried in a compression strut and fork designed by Mr. Dowty, of Aircraft Components, and has a 270 by 100 Palmer tyre. It is very neat and yet at the same time amply sprung for the heavy loads imposed upon it during typical Autogiro landings. It is steerable by cables from a cross foot-bar in the pilot's cockpit.
   The two cockpits are well fitted with the usual instruments, map cases and so on, and the sheet aluminium seats are dished to take Service type parachutes. A plywood floor extends the length of both cockpits and is bolted to small corner pieces of steel plate welded on to the fuselage between the cross bracing and the longerons. The front cockpit has a sliding door on the port side.
   Wide outriggers of pyramid form, which carry the top ends of the Avro oil-and-spring undercarriage compression legs, appear rather massive, but it must be remembered that Autogiro landings impose greater stresses on this particular part of the structure than do the less vertical landings of the normal aeroplane. The upper pyramids are built of streamline-section, steel tube, and the axle radius rods, as well as the compression legs, are faired to streamline shape with Balsa wood fairings; consequently, the drag should not be unduly high.
   Now we come to what may be termed the ''autogiratory" part of this flying machine. The rotor system consists of a three-bladed rotor revolving about a massive head mounted on a form of universal joint, so that it can be tilted in any direction by a control column. This control column is "hanging" as opposed to that in a normal aeroplane, where it is mounted on the floor of the cabin, but the effect is just the same, that is to say, pushing the column forward has the effect of pushing the machine down, and vice versa. A fore-and-aft bias is fitted which trims the Autogiro, much in the same way as the shock absorber cord loading device trims some light aircraft, but it does not have the disadvantage of giving an entirely false feel to the controls. A lateral bias is also arranged to overcome any tendency for the machine to wander from the straight path laterally and directionally.
   At this stage it is probably as well to explain that the rotor is not driven by the engine, but once the machine is in the air it rotates of its own accord, hence its name Auto-giro. Before the machine can fly; however, it is necessary to start up the rotor, and for this purpose there is a shaft drive, operating through a clutch and gearing, from an extension on the back of the engine. Immediately the throttle is opened wide for taking off the rotor clutch is withdrawn, and from then on the rotor operates entirely automatically. The blades have free movement through several degrees in the vertical plane, and a very much smaller movement in the plane of rotation. This latter movement is controlled by friction dampers. Motion in the vertical plane is necessary for aerodynamical reasons and allows the forward-travelling blade to rise and the rearward travelling blade to fall. This movement is also immediately apparent when an Autogiro at rest is compared with one in the air. When stationary it will be seen that the blades droop considerably, whereas in movement they assume a very definite coning angle." Two of the blade hinges are arranged so that the corresponding blades may be folded back when a release pin is pulled out, and thus the Autogiro can, when necessary, be housed in a very narrow space. The blades themselves have a long steel tube spar, ply-faced spruce ribs and a i mm. plywood covering, the extreme tip being shaped from solid Balsa wood. The rotor head itself is a straightforward engineering job, running on ball bearings and incorporating a Bendix brake which allows the blades to be locked when not in use.
   The reasons why the rotor autogyrates cannot be explained in a short article. Briefly, the blades are arranged aerodynamically so that the resultant of the lift and drag forces acts upon them in a slightly forward direction. The effect is to pull the blades round, and the centrifugal force keeps them extended. One of the great advantages of this system is that the speed of the blades through the air is, within limits, not dependent upon the speed of the whole machine through the air. There can, therefore, never be any sudden loss of lift due to the flying speed dropping too low, as whatever the rate of progress of the machine, the blades still rotate at their correct speed. Thus, the air flow over them is unchanged and the lift remains the same. The reader will appreciate from this explanation why a vertical descent is possible with the Autogiro and not with the normal aircraft, as the latter is dependent upon its speed through the air for air speed over its lifting surfaces.

Flight, April 1936

MODERN LIGHT AIRCRAFT REVIEWED

AUTOGIRO

   WITHIN the next few months, it would seem, some very important developments will appear in the autogiratory world. The Cierva Company has always looked upon each new type largely as another step towards an ultimate goal, and we are now waiting for the direct-start type which has been in the course of development for the past year or so. By the simple expedient of altering the axes of the rotor blade hinges and increasing the speed of the initial rotation, a temporary vertical ascent is obtained, and before the machine has time to sink back to the ground it is being pulled forward by the airscrew.
   In the meantime, the present C.30 type continues to do good work, and its performance is, in many important respects, considerably superior to that of the normal fixed-wing aeroplane. Height can be maintained at a forward speed of 15 m.p.h., and the actual contact with the ground is made at 5 m.p.h. or less, while the cruising speed is high enough for all normal purposes.
   A special technique is, of course, necessary when flying the Autogiro, but to anyone who is not a dyed-in-the-wool aeroplane pilot this presents few difficulties. A certain sequence of actions must be made while running up the rotor to 180 r.p.m., releasing the brakes and opening the throttle for the take-off, which is made with the tail wheel in contact with the ground to the very last. The final approach is usually carried in a normal manner at an air speed of 35 to 40 m.p.h. - though it is useful, of course, to toe able to sink vertically, if necessary, during the earlier phases of the approach - and the hold-off and landing are made in the ordinary way, but at a greater height and with considerably greater deliberation. After touching, the stick is pushed forward so as to lose all lift, and if there is anything of a strong wind blowing, the rotor should be stopped after turning to the left out of wind.
   Licences for the manufacture of various types have been granted to A. V. Roe and Company, to Westland Aircraft, and to G. and J. Weir, while the master patents are held by the Cierva Autogiro Co., Ltd., of Bush House, Aldwych, London, W.C.2.