SEV-3 - первый самолет, созданный компанией "Seversky Aircraft Corporation", основанной в 1931 году бывшим россиянином Александром Николаевичем де Северским.
Исходный вариант представлял собою трехместную цельнометаллическую амфибию-низкоплан
с мотором воздушного охлаждения Wright J-6 Whirlwind мощностью 420 л. с. Расположенные тандемом кабины летчика и двух пассажиров закрывались сдвижными фонарями.
Колеса шасси убирались в два главных поплавка с помощью гидравлики. При посадке на аэродром основные поплавки расконтривались и опускались под собственным весом задними частями вниз, чтобы расположенные на концах небольшие колеса коснулись земли раньше, чем основные колеса.
Прототип SEV-3 выполнил первый полет в июне 1933 года, в том же году на нем был установлен мировой рекорд скорости для амфибий с поршневыми моторами. Амфибия строилась небольшой серией только на экспорт. 15 сентября 1935 года на SEV-3M-WW с мотором Wright Cyclone мощностью 710 л. с. был установлен новый мировой рекорд скорости - 370,814 км/ч.
Flight, November 1933
FAST AMERICAN AMPHIBIANS
THE Seversky Aircraft Corporation, of 570, Lexington Avenue, New York, is producing three very interesting amphibians, all characterised by an extremely high performance. The basic layout of all three aircraft is similar, so that the following description of the SEV-3 ("Sportsman"), the first of the series to be built, will give an idea of their design.
The SEV-3 carries three passengers in two tandem cockpits. It is a typical American "high-speed" design, i.e., monocoque fuselage, low cantilever wing and radial engine, fitted with a low drag N.A.C.A.-type cowling.
The wings are of the "cellular" or "multi-box" type. Their smooth outer skin is stiffened internally on the top side by corrugated sheets, with the corrugations running the length of the span. On the bottom the skin is stiffened by closed-channel type longitudinals. The fuselage, in the original model, has seating accommodation for three, but the interior may be altered to carry five. The main bulkhead is attached to corresponding webs of each "box" section of the wing, five points of attachment being provided at the junction of wing and fuselage. The fin is an integral part of the fuselage structure, and the tail plane is attached at four points, thus ensuring the distribution of stresses over a large area of skin. Welded-steel tubes are used for the engine mounting, with rubber vibration absorbers at the points of attachment to the fuselage.
An air brake (known in America as a "descelerator") is carried under the trailing edge of the wing and stretches from aileron to aileron. It is stated that this brake halves the landing run and decreases the landing speed by 15 m.p.h.
Perhaps the most interesting feature of the aircraft is the "universal" landing gear. Twin floats with their wheels are attached to the fuselage by cantilever struts, a pivoting movement being permitted at the points of attachment on the floats. This movement is controlled by small "V" struts located behind the main cantilever struts. As the floats are buttressed with interior keels, they can, in an emergency, be used as landing skids, when landings can be made on ice, snow and rough, marshy or sandy ground. The wheels, which are fitted with hydraulic shock absorbers, protrude through "wells” in the floats. As the result of special attention to the design of the float bottoms these "wells" do not have to be closed to aid take-off. For operation from land the small "V" struts are released, allowing an upward movement of the rear of the floats. Thus an ordinary three-point landing can be made on the two main wheels and a conventional tail wheel. On water the "U" struts are locked and the wheels retracted so that the machine possesses all the characteristics of an ordinary twin-float seaplane. In the event of a forced landing in a confined space the wheels could absorb the initial shock, and then, on the operation of a relief valve, they would retract into the floats, the under portions of which would act as effective brakes. Sudden application of brakes in an emergency is permissible owing to the extension of the floats in front of the machine. A normal retractable land undercarriage can be substituted for the amphibian gear in less than an hour. The wheels, when in the "up" position are housed partly inside the wings and partly in fairings.
The cockpits of the SEV-3 type, which are fitted with dual controls using ball bearings, have sliding roofs and adjustable seats. The pilot has an excellent view for taking off, landing and taxying when his seat is in the uppermost position. An anchor is carried in the nose of one of the floats, and can be released by remote control by the pilot from the cockpit.
As a landplane, when fitted with the 420-h.p. Wright "Whirlwind" engine, the top speed is given as 235. When the supercharged 700-h.p. Wright "Cyclone" is used, the speed, as an amphibian is 245 m.p.h., and 290 m.p.h. as a landplane. The flying radius is 800 miles.
The two other models in the Seversky range are known as the SEV-5 ''Executive'' and the SEV-7 ''Transport." The former is a five-seater, while the latter has a cabin accommodating eight passengers and two pilots. This is in two compartments, one of which is quickly convertible into a "hold" for freight.
On October 9, 1933, a Seversky aircraft established a world's record for amphibians with a speed of 180.3 m.p.h.
Первый самолет Северского - SEV-3XAR. Изначально его построили как амфибию, но потом доработали в самолет только аэродромного базирования. Чистота обводов самолета поражает даже сегодня.
A HIGH-SPEED AMPHIBIAN: An interesting machine designed by Maj. A. Seversky and constructed in New York. The twin duralumin floats contain retractable wheels and when the latter are extended the stern of each float is raised. With a 420-h.p. Wright "Whirlwind" it has an estimated speed of 190 m.p.h. as amphibian or 235 m.p.h. as landplane only. With supercharged 700-h.p. "Cyclone" a speed of 245 m.p.h. is expected as amphibian, or 290 m.p.h. as landplane.
The Seversky amphibian was designed expressly for its job. Its wheels are housed in the floats when retracted.
APTLY NAMED: This is the Seversky amphibian which, fitted with a Wright Cyclone nine-cylinder radial of 750 h.p., recently broke the world's speed record for machines in its class with a speed of 230.03 m.p.h. The fastest lap of the course was made at 236 m.p.h. At the controls was the designer of the machine, Major Alexander de Seversky, who is seen in this photograph. He was accompanied on the record flight by his spaniel.
200 M.P.H.TRAINERS: The widespread adoption of high-speed monoplanes in the U.S.A. has, it would appear, necessitated the provision of special training equipment. Accordingly, the U.S. Army Air Corps has ordered 35 SEV-3XAR monoplanes of the type shown here. Fitted with a 400 h.p. Wright "Whirlwind," the machine has a maximum speed of 200 m.p.h. and the climb to 12,000 ft. occupies ten minutes.
OVER NEW YORK: Major Alexander P. de Seversky flies his latest type, which may yet be entered for the "MacRobertson."
Four Seversky models gathered together at Farmingdale, Long Island, U.S.A., illustrate the persistence of the family likeness. From left to right are the new amphibian two-seater fighter (three of these have already been delivered to the Colombian Government); a landplane version of the machine on which Major de Seversky, its designer, established the world's amphibian speed record with 230.03 m.p.h.; the 1,000 h.p. Twin-Wasp-powered fighter ordered in quantity by the U.S. Army Air Corps; and the basic trainer for the same service.
THE SEVERSKY SEV-3 : Plan, side and front elevations.