Sukhoi Su-9 (1946)
Encyclopedia
The Sukhoi
Sukhoi
Sukhoi Company is a major Russian aircraft manufacturer, headquartered in Begovoy District, Northern Administrative Okrug, Moscow, famous for its fighters...

 Su-9
, or Samolyet K , (USAF/DOD designation: Type 8), was an early jet fighter
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

 built in the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 shortly after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. The design began in 1944 and was intended to use Soviet-designed turbojet engines. The design was heavily influenced by captured German jet fighters and it was subsequently redesigned to use a Soviet copy of a German turbojet. The Su-9 was slower than competing Soviet aircraft and it was cancelled as a result. A modified version with different engines and a revised wing became the Su-11 (Samolyet KL), but this was did not enter production either. The Su-13 (Samolyet KT) was a proposal to re-engine the aircraft with Soviet copies of the Rolls-Royce Derwent turbojet as well as to modify it for night fighting
Night fighter
A night fighter is a fighter aircraft adapted for use at night or in other times of bad visibility...

, but neither proposal was accepted.

Su-9

In 1944, the Sukhoi design bureau (OKB
OKB
OKB is a transliteration of the Russian acronym for "Опытное конструкторское бюро" - Opytnoe Konstructorskoe Byuro, meaning Experimental Design Bureau...

) began designing a twin-engined fighter powered by two Lyulka TR-1 turbojets, known internally as the Samolyet or Izdeliye (item or product) K. The ultimate design was very probably influenced by a captured Messerschmitt Me 262
Messerschmitt Me 262
The Messerschmitt Me 262 Schwalbe was the world's first operational jet-powered fighter aircraft. Design work started before World War II began, but engine problems prevented the aircraft from attaining operational status with the Luftwaffe until mid-1944...

, but the Su-9 was not a copy of the German aircraft. The Su-9 had a oval cross-section, all-metal stressed skin
Stressed skin
In mechanical engineering, stressed skin is a type of rigid construction, intermediate between monocoque and a rigid frame with a non-loaded covering:...

 monocoque
Monocoque
Monocoque is a construction technique that supports structural load by using an object's external skin, as opposed to using an internal frame or truss that is then covered with a non-load-bearing skin or coachwork...

 fuselage that housed a single cockpit. The pilot was protected by armor plates to his front, an armored seat back and a bulletproof windscreen for the bubble canopy
Bubble canopy
A bubble canopy is a canopy made like a soap bubble, which attempts to provide 360° vision to the pilot.-History:Bubble canopies have been in use since World War II. The British had already developed the "Malcolm hood", which was a bulged canopy, but the British Miles M.20 was one of the first...

. He was provided with an ejection seat, copied from that used in the Heinkel He 162
Heinkel He 162
The Heinkel He 162 Volksjäger was a German single-engine, jet-powered fighter aircraft fielded by the Luftwaffe in World War II. Designed and built quickly, and made primarily of wood as metals were in very short supply and prioritised for other aircraft, the He 162 was nevertheless the fastest of...

. The aircraft carried a total of 1350 kilograms (2,976.2 lb) of fuel in two bladder tanks, one each ahead and behind the pilot. The low-mounted, straight wing had a single-spar
Spar (aviation)
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings whilst on the ground...

 and a slight dihedral of 4°20'. The outer flap
Flap (aircraft)
Flaps are normally hinged surfaces mounted on the trailing edges of the wings of a fixed-wing aircraft to reduce the speed an aircraft can be safely flown at and to increase the angle of descent for landing without increasing air speed. They shorten takeoff and landing distances as well as...

s were split and could act as air brake
Air brake (aircraft)
In aeronautics, air brakes or speedbrakes are a type of flight control surface used on an aircraft to increase drag or increase the angle of approach during landing....

s. The Su-9 was the first Soviet aircraft to use hydraulic powered controls. A Soviet copy of the Junkers Jumo 004
Junkers Jumo 004
The Jumo 004 was the world's first turbojet engine in production and operational use, and the first successful axial compressor jet engine ever built. Some 8,000 units were manufactured by Junkers in Germany during late World War II and powered the operational Messerschmitt Me 262 jet fighter,...

B turbojet, known as the RD-10, was hung under each wing in a streamlined nacelle
Nacelle
The nacelle is a cover housing that holds engines, fuel, or equipment on an aircraft. In some cases—for instance in the typical "Farman" type "pusher" aircraft, or the World War II-era P-38 Lightning—an aircraft's cockpit may also be housed in a nacelle, which essentially fills the...

. The aircraft had a tricycle undercarriage that retracted into the fuselage. The Su-9 was designed with a very high wing loading
Wing loading
In aerodynamics, wing loading is the loaded weight of the aircraft divided by the area of the wing. The faster an aircraft flies, the more lift is produced by each unit area of wing, so a smaller wing can carry the same weight in level flight, operating at a higher wing loading. Correspondingly,...

 which increased the aircraft's speed and reduced its dimensions. This consequently increased the take-off and landing speeds so it was equipped with a provision for two JATO
JATO
JATO is an acronym for jet-fuel assisted take off. It is a system for helping overloaded aircraft into the air by providing additional thrust in the form of small rockets....

 bottles (11.27 kN (530 lbf) thrust for 8 seconds) mounted on the sides of the fuselage. These reduced the take-off distance by nearly 50 percent and a braking parachute was fitted to reduce the landing distance.

The nose housed the armament of one 37 millimetres (1.5 in) Nudelman N-37
Nudelman N-37
The N-37 was a powerful, 37 mm aircraft cannon used by the Soviet Union. It was designed by V. Ya. Nemenov of A.E. Nudelman's OKB-16 to replace the wartime Nudelman-Suranov NS-37, entering service in 1946...

 autocannon
Autocannon
An autocannon or automatic cannon is a rapid-fire projectile weapon firing a shell as opposed to the bullet fired by a machine gun. Autocannons often have a larger caliber than a machine gun . Usually, autocannons are smaller than a field gun or other artillery, and are mechanically loaded for a...

 and two 23 millimetre (0.905511811023622 in) Nudelman-Suranov NS-23
Nudelman-Suranov NS-23
The NS-23 was a aircraft cannon designed by A. E. Nudelman, A. Suranov, G. Zhirnykh, V. Nemenov, S. Lunin, and M. Bundin during World War II as a replacement for the Volkov-Yartsev VYa-23 cannon. It entered service in 1944...

 autocannon. The N-37 could be replaced by a 45 millimetres (1.8 in) Nudelman N-45. The aircraft carried 100 rounds for each NS-23 and 40 rounds for the N-37. Two 250 kilograms (551.2 lb) FAB-250 high explosive bombs could be carried underneath the forward fuselage, but the N-37 had to be dismounted to do so.

As the TR-1 engines originally intended for the Su-9 were not yet ready for flight testing in late 1945, Pavel Sukhoi
Pavel Sukhoi
Pavel Osipovich Sukhoi was a Soviet aerospace engineer. He designed the Sukhoi military aircraft and founded the Sukhoi Design Bureau. -Biography:...

 suggested substituting a pair of Jumo 004 engines and this was approved on 15 December. The full-scale mockup
Mockup
In manufacturing and design, a mockup, or mock-up, is a scale or full-size model of a design or device, used for teaching, demonstration, design evaluation, promotion, and other purposes...

 was found to be acceptable on 16 February 1946 and the Council of People's Commissars issued an order on 26 February that the manufacturer's flight testing was to begin on 1 November. This goal was not met because the OKB was heavily committed to other projects like the trainer version of the Tupolev Tu-2
Tupolev Tu-2
|-See also:-References:NotesBibliography* Bishop, Chris. The Encyclopedia of Weapons of WWII: The Comprehensive Guide to Over 1,500 Weapons Systems, Including Tanks, Small Arms, Warplanes, Artillery, Ships, and Submarines. New York: Sterling, 2002. ISBN 1-58663-762-2.* Ethell, Jeffrey L. Aircraft...

 bomber, inexperience with JATO units, and late delivery of RD-10 engines. The first prototype was completed in mid-October and made its first flight on 13 November. The test pilots found the aircraft easy to fly, but the control forces were very high at speed and it lacked enough directional stability. Enlarging the vertical stabilizer cured this last problem and hydraulic boosters were fitted for the control system.

The aircraft was revealed to the general public on 3 August 1947 at a flypast at Moscow's Tushino Airfield and the aircraft began its state acceptance trials three days later. Flight testing was completed by 25 May 1948 after 136 flights had been completed. It demonstrated a top speed of 885 kph at an altitude of 8000 metres (26,246.7 ft) and an endurance of one hour and 44 minutes. It had very docile handling qualities with one engine inoperative. The aircraft was recommended for production, but it was significantly slower than the Mikoyan-Gurevich MiG-9
Mikoyan-Gurevich MiG-9
The Mikoyan-Gurevich MiG-9 was the first Soviet turbojet fighter developed by Mikoyan-Gurevich in the years immediately after World War II. It used reverse-engineered German BMW 003 engines...

 and Yakovlev Yak-15
Yakovlev Yak-15
The Yakovlev Yak-15, NATO reporting name: Feather, USAF/DOD designation Type 2) was a first-generation Soviet turbojet fighter developed by the Yakovlev design bureau immediately after World War II. It used a reverse-engineered German Junkers Jumo 004 engine...

. The government declined to do so and the program was terminated.

A two-seat trainer version, the Su-9UT, was planned during 1946, but it too was cancelled. The cockpit for the student would have been positioned ahead of the instructor's cockpit and each would have had a separate canopy. The armament would have been reduced to a pair of 20 millimetre (0.78740157480315 in) Berezin B-20
Berezin B-20
The Berezin B-20 was a 20 mm caliber autocannon used by Soviet aircraft in World War II.-Development:The B-20 was created by M.E. Berezin in 1944 by chambering his Berezin UB 12.7 mm machine gun for the 20 mm rounds used by the ShVAK cannon...

 autocannon, each with a hundred rounds of ammunition. The armor would have been removed to save weight.

Su-11

Another prototype was begun in 1946, but this aircraft was intended to use the Yakovlev
Yakovlev
The Yak Aircraft Corporation is a Russian aircraft designer and manufacturer...

-designed version of the afterburning RD-10F engine. However, wind tunnel
Wind tunnel
A wind tunnel is a research tool used in aerodynamic research to study the effects of air moving past solid objects.-Theory of operation:Wind tunnels were first proposed as a means of studying vehicles in free flight...

 testing of the Su-9 in September revealed that drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...

 could be reduced if the engine nacelles were mounted in the wing rather than underneath it, and the wing tips were redesigned to use a different airfoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....

 that significantly reduced Mach tuck
Mach tuck
Mach tuck is an aerodynamic effect, whereby the nose of an aircraft tends to pitch downwards as the airflow around the wing reaches supersonic speeds...

. These changes required that the entire wing be redesigned; the wing spar was bent into an inverted U to accommodate the engines and slotted flaps replaced the simple flaps previously used. The tailplane was given a 5° dihedral to move it out of the engine exhaust.

Before the prototype was finished, Sukhoi was ordered to use the Lyulka TR-1 turbojets originally intended for the Su-9. This aircraft was designated the Su-11 and was called Samolyet KL by the OKB. Each TR-1 developed only 12.7 kN (2,865 lbf) thrust each, rather than the 15 kN (3300 lbf) required. The aircraft made its first flight on 28 May 1947 and also participated in the flypast at Tushino in August. It had a maximum speed of 940 kph at sea level, but flight testing revealed that it lacked longitudinal stability at high speeds. Modifications of the wing/nacelle fillet
Fillet (mechanics)
In mechanical engineering, a fillet is a concave easing of an interior corner of a part design. A rounding of an exterior corner is called a "round" or a "chamfer".-Applications:...

s and lengthening the engine nacelles failed to cure these problems. Coupled with the unavailability of mature TR-1 engines, these problems caused the program to be cancelled.

Su-13

The Su-13, (Samolyet KT), was the final attempt to further increase performance of the basic Su-9 design, using wing sections reduced from 11% to 9% thickness/chord
Chord (aircraft)
In aeronautics, chord refers to the imaginary straight line joining the trailing edge and the center of curvature of the leading edge of the cross-section of an airfoil...

 ratio and swept
Swept wing
A swept wing is a wing planform favored for high subsonic jet speeds first investigated by Germany during the Second World War. Since the introduction of the MiG-15 and North American F-86 which demonstrated a decisive superiority over the slower first generation of straight-wing jet fighters...

 tailplanes. The aircraft was also fitted with a pair of Klimov RD-500
Klimov RD-500
The Klimov RD-500 was an unlicensed Soviet copy of the Rolls-Royce Derwent Mk.V turbojet that was sold to the Soviet Union in 1947. The Klimov OKB adapted it for Soviet production methods and materials.-Development:...

 (unlicensed copies of the Rolls-Royce Derwent) engines with 15.6 kN (3,500 lbf) thrust each. The armament was changed to three 37 mm Nudelman N-37 cannon, while drop tank
Drop tank
In aeronautics, a drop tank is used to describe auxiliary fuel tanks externally carried by aircraft. A drop tank is expendable and often jettisonable...

s could be fitted underneath the wingtips. A night fighter
Night fighter
A night fighter is a fighter aircraft adapted for use at night or in other times of bad visibility...

 version with a Torii radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

 was also proposed, but this required major structural changes to accommodate the radar. Neither version made it off the drawing board.

Variants

  • Su-9UT – Planned two-seat trainer version, never built.
  • Su-11 (Samolyet KL) – Modified Su-9 with new wings and Lyulka TR-1 engines. One prototype built.
  • Su-13 (Samolyet KT) – Su-9 with Klimov RD-500 engines. Night fighter version also proposed. Neither version was built.

Specifications (Su-9)

See also

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK