Junkers K 47 / A 48
Страна: Германия
Год: 1928

Двухместный истребитель
Junkers A 48 и K 47
Flight, May 1931
I.L.I.S. The Stockholm International Aero Show
Flight, March 1934
A Swedish Two-Seater Fighter: The Junkers K.47

Junkers A 48 и K 47

В 1927 году Карл Плаут приступил к проектированию двухместного истребителя по запросу Турции. Этот самолет отличался гладкой обшивкой, вместо обычного для компании "Junkers" гофрированного дюраля, и двухкилевым оперением. В ноябре того же года Плаут погиб, и проектирование A 48 возглавил Герман Польман. К этому времени Турция уже потеряла интерес к машине, но оставалась надежда на получение заказа от СССР, и разработку продолжили.
   Первый прототип A 48 взлетел 15 сентября 1929 года, а затем в Дессау построили еще шесть машин. Эти самолеты предназначались для испытаний и отличались, прежде всего, силовыми установками. Один из них получил V-образное оперение, а другой (D-2284) был задействован в проводившихся впервые в мире испытаниях по бомбометанию с пикирования в Бреслау. Результаты, полученные в ходе этих полетов, в дальнейшем пригодились Польману при разработке пикирующего бомбардировщика Ju 87. Считается, что было построено 23 самолета A 48, включая военные варианты K 47, которые дорабатывались или производились шведской "AB Flygindustri". В 1929 году это предприятие из Лимхэма поставило 12 машин K 47 Китаю, а еще два самолета были закуплены для испытаний советскими ВВС. Три или четыре машины поступили в учебный центр германских ВВС в Липецке. Несколько самолетов недолгое время использовалось для подготовки экипажей пикирующих бомбардировщиков.


   Junkers K 47ba

   Тип: двухместный истребитель
   Силовая установка: один 9-цилиндровый радиальный двигатель Pratt & Whitney Hornet (выпускавшийся по лицензии BMW), 591 л. с. (441 кВт)
   Летные характеристики: максимальная скорость 300 км/ч; потолок 4250 м; дальность полета 490 км
   Масса: пустого 1050 кг; макс. взлетная 1635 кг; полезной нагрузки 585 кг
   Размеры: размах крыла 12,40 м; длина 8,55 м; высота 2,40 м; площадь крыла 22,80 м2
   Вооружение: один 7,92-мм пулемет LMG 08/15 в носовой части и один 7,92-мм пулемет на турели в задней кабине

Flight, May 1931

I.L.I.S. The Stockholm International Aero Show
May 15-31, 1931

   The problem single-seater or two-seater fighter is a very complicated one, and does not come within the province of an article on the exhibits at an aero show. A brief reference must, however, be made to it in order to explain the raison d'etre of the machine shown by the Swedish company, A.B. Flygindustri, of Malmo. This is a two-seater fighter known as the type K.47, and is a Junkers design built under licence in Sweden by this company, who holds the building rights in Sweden for all Junkers types.
   From strategical and tactical considerations, this firm has come to the conclusion that a flight of five two-seater fighters is equivalent in offensive and defensive power to a flight of seven single-seater fighters. These considerations, into which it would take too long to go here, take into account the "blind areas" of both types, the increase in effective field of fire attained by the climbing or diving through 60 degrees from the horizontal, the inability of the rear machines in a flight to fire in certain forward directions owing to the positions of certain machines of the flight, the various formations, such as vee formation stepped up and stepped down, and so forth. The arguments advanced in favour of the two-seater fighter are interesting, and may be referred to on a future occasion. For the present, we must confine ourselves to stating that A.B. Flygindustri have gone into the subject very carefully, and that the K.47 has been produced as a result.
   The machine, by the way, is not unknown to English readers of FLIGHT, as it paid a visit to Heston Air Park in 1929, and a photograph of it was published in our issue of July 25, 1929. Like all Junkers aircraft, the K.47 is of all-metal construction, but it differs from most Junkers machines in that it is not a cantilever monoplane, but has a braced wing structure. It is stated, however, that the load factors are such that, even with a wing bracing strut shot away, the wing, as a cantilever, has a factor of 4-5, so that the machine should be able to return safely, even if not in a fit state to take any further part in a fight entailing violent manoeuvres.
   The structural design of the K.47 follows fairly closely usual Junkers practice, with the exception of the wing bracing already referred to. Duralumin is the chief structural material, with a few steel fittings for highly-stressed parts. The torsional strength of the wing depends mainly upon the duralumin covering, which, it is claimed, can be riddled with machine-gun bullets without the torsional strength being materially reduced.
   The pilot's cockpit of the K.47 is of normal layout, and his armament consists of the usual two fixed machine guns, firing forward. The gunner's cockpit, however, is the centre of interest in this machine, and is the key to the whole design. The fuselage is so shaped as to obstruct the view and field of fire as little as possible. To this end it is of narrow beam over the rear part, while the tail is set low, and the decking slopes down at a considerable angle. This has been done so as to enable the gunner to fire downward at a slight angle (some 3 degrees) below the horizontal. The upward angle of the gun is 90 degrees, so that the total elevation range is 93 degrees. Firing broadsides at the speeds attained by modern fighters is regarded by the designers as almost impossible in any case, and so no attempt to allow of this has been made. Instead, the lateral movement of the rear gun has been limited to 18 degrees on each side of the centre line of the machine, or a total of 36 degrees. This amount of traverse is entirely unobstructed, because, instead of the usual centrally-placed rudder, the K.47 has two rudders, placed near the tips of the tailplane. In this position they are outside the range of the gun, and there is thus no risk of the gunner shooting his rudders or fins away.
   The gun mounting is interesting, and is of a type known in Sweden as a "gunglavett," a "gung" being a rocker (of a rocking-horse, for example), and "lavett" meaning a mounting. This "rocker-mounting" consists in effect of a beam supported near its centre on a pivot, and carrying at one end the machine gun and at the other the gunner's seat. Its object is to enable the gunner to operate his gun even while the machine is making a very sharp turn, when otherwise centrifugal force would prevent him from moving about. Windage on the gun when it is swung outboard to the limits of its traverse is counteracted by a spring device, the strength of which is so proportioned to the angle of the gun as to keep the force required to traverse approximately constant.
   The gunner's seat has a tall backrest, tall enough to reach to head level and enable the gunner to rest his head firmly against it. A projection of the deck fairing between the cockpits acts as a wind-screen for the rear gunner and relieves his head and neck of most of the air pressure. The whole arrangement of the rear cock-pit is highly ingenious, but the "rocker mounting" would appear to be just a little complicated.
   The K-47, which is fitted with a Bristol “Jupiter" VII supercharged engine, has a length of 8.55 m. (28 ft. 1 in.). The wing span is 12.4 m. (40 ft. 8 in.) and the wing area 22.8 sq. m. (245.5 sq. ft.), the tare weight is 1,050 kg. (2,310 lb.) and the gross weight 1,635 kg. (3,600 lb.).
   When fitted with the Bristol "Jupiter" VII supercharged engine, the K.47 has a maximum speed at 3.500 m. (11,500 ft.) of 290 km./h. (180 m.p.h.). At 5,000 m. (16,400 ft.) the speed is 280 km./h. (174 m.p.h.). The speed at ground level is 245 km./h. (152 m.p.h.). The landing speed is about 100 km./h. (62 m.p.h.). The climb to 3,000 m. (10,000 ft.) occupies 6 minutes, and the service ceiling of 8,500 m. (28,000 ft.) is reached in about 35 minutes. The tankage is sufficient for 2 hours at full throttle and 16,400 ft. altitude.

Flight, March 1934

A Swedish Two-Seater Fighter: The Junkers K.47

   UNLIKE the majority of Junkers types produced during recent years, the type K.47 built in Sweden by the A.B. Flygindustri was designed primarily as a military type. The aircraft is a braced low-wing monoplane, with the wing consisting of a centre section, which is integral with the fuselage and two outer sections of trapezoidal shape. Spherical screw joints connect the wings to the centre section, and a single strut braces each outer wing to the undercarriage.
   Structurally the wing is of typical Junkers multi-tube type, the torsional stresses being taken by corrugated sheet covering. A fuselage of oval section is used which consists of three parts, the engine section, the centre section containing the cockpits and the tail portion. The wing centre section and fuselage centre section are built up as one unit. Duralumin longerons are used, braced by transverse members of the same material. Unlike the wings, the fuselage has a covering of smooth sheet duralumin.
   Ailerons of high aspect ratio, statically and aerodynamically balanced, are used. The tail plane is adjustable in flight and is provided with a self-locking spindle adjustment controlled by a hand wheel in the pilot's cockpit. The elevators and tail plane are so large that the aircraft, when fully loaded and with the C.G. back, is still quite stable. Two fins with two balanced rudders are fixed to the extreme ends of the tail plane. This arrangement allows a very wide rearward field of fire for the movable gun. One disadvantage, however, is presented, in that the machine is not so easily manoeuvred on the ground. This handicap is overcome by the provision of wheel brakes and a tail wheel.
   The controls are of the conventional stick and rudder bar type, and all joints are provided with ball bearings. A cross axle type undercarriage, using two Vickers oleo pneumatic legs is fitted. The extremities of the axle are hinged by radius rods to two rigid Vee's interconnected by a cross strut. To this Vee is attached the main wing bracing. Palmer wheels and brakes, the latter being operated by pedals on the rudder bar, are usually provided.
   Almost any air-cooled radial engine with a dry weight of approximately 882 lb. and with a power of from 500 h.p. to 600 h.p. may be fitted. In the prototype a "Jupiter VII" engine was used, but later this was changed for a Bristol "Mercury IV S.2" of 540 h.p. with a corresponding increase in performance. Two electron fuel tanks of 37 and 31 gallons capacity are carried beneath the centre section, supplemented by one gravity tank of 10 pints capacity. There is one engine-driven fuel pump and one hand pump is provided.
   Like the majority of modern two-seater fighters, the K.47 is armed with two fixed machine guns and a movable gun over the rear cockpit. Space for about 1,000 rounds per gun, in standard metal clip belts, is provided behind the fireproof bulkhead. Any standard machine gun, such as the Vickers, Madsen or Colt, may be installed. The equipment of the gunner's cockpit differs greatly from that of conventional two-seaters. When standard ring mountings are used in high-speed aircraft, difficulties arise as a result of the air pressure against gunner and guns, and to the acceleration due to sharp turns or steep banks. In order to cope with present conditions, the K.47 is fitted with a "cradle mounting" This consists of a pivoted mounting carrying at one end the gun and the other the gunner's seat. The mounting is so balanced that it gives the gunner a slight excess of weight, thus enabling him by means of pressure with his feet to rock the whole device up and down. The performance figures given in the accompanying table apply to the K.47 fitted with the Bristol "Mercury IV S.2" engine. When fitted with the Pratt & Whitney "Hornet S.2-V1," the maximum speed at 7,874 ft. (2 400 m) is 192.6 m.p.h. (310 km/h.), and the cruising speed at 7,874 ft. (2 400 m) is 163.4 m.p.h. (263 km/h.).


   Span 41 ft (12 4 m)
   Length 27 ft. (8,8 m)
   Height 8 ft. 10 in. (2,9 in)
   Wing area 250 sq. ft. (23,5 m1)
   Weight, empty 2,540 lb. (1 150 kg)
   Disposable load 1,320 Ib. (600 kg)
   Wing loading 15-5 lb./sq.ft. (73,1 kg/m1)
   Power loading 7 lb./h.p. (3,2 kg/h.p.)
   Maximum speed at 13,120 ft. (4 000 m) 200 m.p.h. (324 km/h.)
   Cruising speed at 13,120 ft. (4 000 m) 171 m.p.h. (276 km/h.)
   Climb to 3,280 ft. (1 000 m.) 2 min.
   Climb to 13,120 ft. (4 000 m.) 8 min.
   Service ceiling 31,824 ft. (9 700 m)
   Absolute ceiling 32,808 ft. (10 000 m)
   Range 420 miles (675 km )
Marking a radical departure from Junkers’ patented corrugated Duralumin skin concept, the K 47/A 48 was initially built with a completely smooth skin, although old habits die hard, and production versions incorporated corrugated sections. This A 48, D-2012, was used by the DVL for trials at Berlin-Adlershof from 1930.
Был построен только один экземпляр A 48dy, регистрационный номер D-2012, оснащенный двигателем Siemens Sh20 мощностью 540 л. с. (402 кВт). В июне 1931 эта машина проходила испытания в экспериментальном центре Адлерсхоф в Берлине.
The A 48 was the “civil” variant of the military K 47, although they were essentially the same aircraft, the A 48 merely being unarmed and with new fuselage decking added around the rear cockpit. This example, D-2012 (c/n 3365), was delivered to the DVL as a test machine in June 1930.
Предшественник "штуки" пикирующий истребитель-штурмовик Юнкерс K-47
In stark contrast to Junkers’ traditional square-angled corrugated skin, the K 47 prototype was given a much more elegant and streamlined smooth skin throughout, although the wings and the tail surfaces of production machines incorporated corrugated skins. Note the original bracing wires linking the wings to the undercarriage cradle and to the pylon between the cockpits.
Originally registered as S-80, then S-AABW, and finally SE-ABW, the much-travelled prototype is seen here with underwing struts replacing the original bracing wires, and the specially designed suspended gun mounting in the rear cockpit, which enabled the rear gunner to operate the Madsen machine-gun while seated.
Junkers K.47 low-wing monoplane with twin tail (Bristol "Jupiter" engine) on which Herr W. Neuenhofen won third place and ?20 in the International Aerobatic Competition.
Юнкерс K-47
With the retirement of SE-ABW as a demonstration machine, fourth production K 47 SE-ACF (c/n 3355) was used for sales tours to Turkey and Portugal in 1930. Neither, however, placed orders for the type. Note the distinctive corrugated tail-section surfaces.
Fitted with a Bristol Jupiter VII engine, A 48 D-2284 (formerly demonstrator SE-ACF) is seen here during the 1932 election campaigns for the Nationalsozialistische Deutsche Arbeiterpartei (Nazi Party), during which it wore swastikas on the undersurfaces of the outer wing sections. These were only temporary markings, however.
The second K 47 which was eventually used as a Junkers demonstrator (as the A 48b).
The original Stuka? Hornet-engined development K 47/A 48 SE-ADL (c/n 3356) was equipped for dive-bombing trials at Bofors’ shooting range in Sweden with underwing bomb-racks provided by Finland’s llmavoimat and measuring equipment, as seen here on the undercarriage struts.
With a Townend-type ring-cowling fitted to its BMW Hornet engine, A 48 demonstration and trials machine D-2284 (c/n 3355) displays its underwing-mounted divebrakes. With its sturdy construction and good handling characteristics, the type proved valuable for research into the nascent art of dive-bombing.
Despite being completely obsolete by the mid to late 1930s, at least three examples of the A 48/K 47 survived into the 1940s and received Luftwaffe Balkenkreuz markings and codes, as seen on this BMW Hornet-engined example. The type’s designer, Hermann Pohlmann, refined the dive-bomber with his famous Ju 87 Stuka.
Двухместный истребитель "Юнкерс" K-47. В начале 1930 гг. такие машины состояли на вооружении гоминьдановских ВВС и принимали участие в боях над Шанхаем.
The unusual prospect of a Junkers fighter in the six o’clock position! The K 47 was initially fitted with a twin-finned tail, in order to provide a good field of fire for the rear gunner, but a pair of forward-firing machineguns was also fitted, with a synchronisation gear to fire through the propeller arc.
Six BMW Hornet-engined K 47s were ordered by the Nanking government in China in May 1931, which, with the purchase of the example sent the previous year, were given the serials P-1 to P-7, the last of which is seen here.
Three Chinese K 47s await their next sortie, including, nearest the camera, demonstrator c/n 3356, originally SE-ADL. This was acquired and donated to the Nationalist Air Force by the T’ien C’hu Seasoning Powder Factory, whose name was painted on the fuselage aft of the rear cockpit, as seen here.
German flying instructors Erich Brammen (fifth from left) and Hermann Frommherz (second from right) enjoy a pause in activities during the training of Chinese K 47 pilots in late 1931. The Chinese K 47s sported the Nationalist roundel, based on the Kuomintang’s symbol incorporating a white sun with 12 cantons on a “blue sky” field, with a red outer ring.
Junkers test pilot Johann Riszticz (right) beside the first of the Nanking government’s K 47s, which arrived in October 1930.
Seen here completely without markings before delivery, A 48 SE-ACT (c/n 3371) was one of three acquired in 1931 for use at the Erprobungsstelle testing station at Travemiinde, although this was the only one of the trio fitted with a single fin and revised tailplane, which incorporated control surfaces of corrugated construction
Seen here fitted with a BMW Hornet A-2 engine, A 48 c/n 3362 started its career at the German test centre at Lipetsk in the Soviet Union in June 1930. It was later registered as D-1057, before another spell at Lipetsk and its final return to Germany as D-INUT, as which it was used by the Deutsche Verkehrsflieger-Schule (DVS - German Air Traffic Pilots’ School) as a trainer at Schleissheim.
Junkers K 47 P-3 was one of the original seven purchased by the air force of the Central Government.
Эскиз проекта «звена» с носителем ТБ-1 и двумя самолетами Юнкерс K.47 на его крыле
This original Junkers three-view drawing, entitled Dimensions and Designations, is dated February 1930, and shows the leading particulars of the twin-finned Jupiter-engined A 48 b.
The Hornet-powered K 47 as supplied to the Central Chinese government