Fokker T.IV

Один из самых внешне неказистых самолетов производства фирмы "Fokker", двухмоторный разведчик-торпедоносец T.IVA, был глубокой модернизацией проекта T.IV 1927 года. Всего построили 18 машин этого типа для службы в метрополии и в Голландской Ост-Индии. Португалия также приобрела три таких аэроплана.
   T.IVA отличался от своего предшественника главным образом силовой установкой, получив звездообразные 750-сильные моторы Wright Cyclone SR-1820-F2 вместо W-образных моторов Lorraine-Dietrich T.IV мощностью 450 л. с. (336 кВт). Для более мощных моторов потребовалось усиление планера. Одновременно были установлены закрытая кабина пилота, а также пулеметные установки в носовой части, надфюзеляжной и подфюзеляжной позициях. 12 машин заказала авиация флота голландской Ост-Индии. В 1936 году все T.IV были переделаны до стандарта T.IVA.
   Полеты на прибрежную и дальнюю морскую разведку в Голландской Ост-Индии выполнялись вплоть до начала вторжения японцев в 1942 году. Самолеты T.IVA также использовались для спасательных работ, проявив высокую надежность и неплохие мореходные качества.


ТАКТИКО-ТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ

   Fokker T.IVA

   Тип: четырехместный разведчик/торпедоносец
   Силовая установка: два звездообразных поршневых девятицилиндровых мотора Wright Cyclone SR-1820-F2 мощностью по 750 л. с. (559 кВт)
   Летные характеристики: максимальная скорость 260 км/ч на высоте 800 м, крейсерская скорость 215 км/ч; практический потолок 5900 м, радиус действия 1560 км
   Масса: пустого 4665 кг; максимальная взлетная 7200 кг
   Размеры: размах крыла 26,20 м; длина 17,60 м, высота 6,00 м; площадь крыла 97,80 м2
   Вооружение: по одному 7,9-мм пулемету в носовой, надфюзеляжной и подфюзеляжной стрелковых установках, до 800 кг бомб на внутренней подвеске либо одна торпеда под фюзеляжем

Flight, January 1928

THE FOKKER T. IV SEAPLANE
A Twin-Engined Torpedo or Bombing Monoplane

   ONE of the latest products of the well-known Dutch firm of Fokker is the T. IV Seaplane, which forms the subject of our description this week. We understand that this machine is being employed by the Dutch Royal Air Force for use in the Dutch East Indies.
   The T. IV seaplane is a twin-engined, twin-float cantilever monoplane with the wing on top of the fuselage. Although designed primarily as a bomber or torpedo carrier, it can nevertheless easily be employed as a commercial machine by making a few alterations to the fuselage and fitting a cabin. Also, if desired, the two floats may be replaced by wheel landing gear. A clear space under the fuselage, between the floats, is provided for the mounting of torpedoes or bombs.
   Contrary to the method usually employed in other Fokker monoplanes of fixing the wing to the fuselage by means of four bolts, the wing of the T. IV is not directly attached to the fuselage. Although the wing of the T. IV lies on the fuselage - as in the case of the Fokker F. VII and F. VIII - actually it is affixed, by four bolts, to a steel-strut structure or cabane, above each float, which is built-up with and welded to the fuselage. This structure, as may be seen from our illustrations, comprises a series of inverted V-struts extending upwards from the floats, with additional struts extending top and bottom to suitable points on the fuselage.
   Constructionally, the T. IV wings follow usual Fokker practice, comprising two box spars with profile section ribs slid on to them, the whole covered with plywood covering. They also taper sharply from root to tip, both in thickness and in plan form. Small aluminium doors have been hinged on to the covering at intervals to permit the aileron control cables being examined.
   The ailerons, which are of wood throughout, are of high aspect ratio and are unbalanced. The tail surfaces are mounted on the top of the fuselage high up out of the way of the water, and are constructed of steel tubes covered with fabric. Elevators and rudders are balanced, and the vertical surfaces are of large proportions. Both the horizontal stabilising surface and the vertical fin are adjustable during flight from the pilot's cockpit. Dual control is provided.
   As with other Fokker machines, the fuselage of the T. IV is constructed with seamless drawn welded steel tubes, braced in the forward part by steel tubes, and in the rear part by piano-wire. The fuselage is divided from stem to stern into the following sections - front observer's cockpit with gun post; pilots' cockpit; bomb room; rear observer's cockpit with gun post; and the tail.
   Each compartment is connected up with the other and on each side of the bomb compartment are strong joists or supports, to which are welded the struts carrying the wings and undercarriage.
   The front gunner's cockpit provides an uninterrupted view over a wide area, giving a large field of fire. It is also very large, there being sufficient room for installing various instruments such as bomb sight, navigation instruments, etc. A passage, passing under the pilot's cockpit, communicates with the central bomb compartment.
   Immediately in front of the leading edge of the wing is the pilot's cockpit, which is provided with two seats side by side, sufficiently high so as to enable the pilots to look over the engines to the wing tips. In addition to being adjustable both seats arc collapsible, so as to give free access between the front observer's cockpit and the bomb room.
   The pilot's cockpit contains the usual navigation and engine instruments as well as the controls for engines and radiators, ignition switches, and the cranks for adjusting the stabiliser and fin.
   The bomb room, which measures 4 ft. 6 in. by 4 ft. 6 in. by 7 ft. 9 in., is constructed with racks for different-sized bombs (four 200 kg. bombs and 18 of 50 kg.), carried inside the fuselage. If no bombs are carried, provision is made for carrying a torpedo on a specially-constructed carrier under the fuselage. In the floor is a diamond-shaped opening, 4 ft. 6 in. wide and 8 ft. 6 in. long; on either side of the bombs there is ample room to pass from the front and rear cockpits.
   Finally, the rear observer's cockpit, measuring 4 ft. 4 in. by 4 ft. 4 in. by 14 ft. 4 in., provides adequate room for carrying a variety of equipment, such as cameras, wireless installation, reserve cases of ammunition, signalling gear, etc. About half-way along the length of this compartment there is a fairly sharp rise in the bottom of the fuselage, which enables a machine gun to be mounted, firing downwards and astern. There is also a machine gun ring, with an extremely large field of fire, on the top of the fuselage.
   It should be mentioned that the fuselage is constructed in such a way that if any of the welded steel tubes should sustain damage, through an airscrew breaking, etc., there is still inherent strength enough to allow flight being continued.
   The "broad-arrow" type 450 h.p. Lorraine Dietrich engines, with reduction gear, are fitted, but it is also possible to install any other air or water-cooled engine of not less than 450 h.p. - such as, for instance, the B.M.W. VI, Hispano Suiza, Napier "Lion," Bristol "Jupiter VI," Isotta Fraschini Asso, etc.
   Each of the engines are mounted above the floats, on two bearers, which are attached to the cabane structure previously mentioned, while there are three struts extending from the engine (at approximately the c.g. of the latter) to the floats. At the side the engine is supported by a strut slanting up from the fuselage. Each engine is enclosed in a streamline cowling of aluminium plates, which connects up with the leading edge of the wing, and which is continued over the wing in cases where the exhaust pipes of the engine are at a distance of less than 50 cm., or 20 in. from the wing.
   The fuel tanks, which have a total capacity of 1,500 litres (330-75 gals.), are installed in the centre of the wing, between the spars. The oil tanks, which are in the leading edge of the wing, contain about 40 litres (8-8 gals.) each. Under each engine is a tubular radiator, regulated by retraction.
   The floats, each of 6-15 cu. m. (47-2 cu. ft.) capacity, are of duralumin throughout. They are divided into six sections separated by watertight bulkheads ; each section is provided with a lid for inspection purposes, and there are also manholes in the deck. Bollards are provided for towing purposes.
   The principal characteristics of the T.IV are :-
   Span 84 ft. 7 1/2 in.
   O.A. length 57 ft. 8 1/2 in.
   O.A. height 19 ft. 8 in.
   Wing area 1,033 sq. ft.
   Weight, empty 9,150 lbs.
   Useful load 5,300 lbs.
   Total weight 14 450 lbs.
   Weight per sq. ft. 14 lbs.
   Weight per h.p. 16 lbs.
   Speed range 60-125 m.p.h.
   Cruising speed 103 m.p.h.
   Range 7 1/2 hrs. or 750 miles
   Climb, 1,000 m. (3,280 ft.) 6-8 mins.
   ,, 3,000 m. (9,840 ft.) 29 mins.
   Ceiling (service) 12,150 ft.
   ,, (absolute) 14,450 ft.
"Everling Quantities."
   High-speed Figure 16
   Distance Figure (top speed) 5-5
   Altitude Figure (ceiling) 7-6