Engineering:Sukhoi Su-9

Short description: 1959–1970s Soviet interceptor aircraft

Su-9
Role	Interceptor aircraft
National origin	Soviet Union
Manufacturer	Sukhoi
First flight	June 24, 1956
Introduction	1959
Retired	1970s
Primary user	Soviet Air Defense Forces
Number built	1,150
Developed from	Sukhoi T-3
Variants	Sukhoi Su-11

The Sukhoi Su-9 (ASCC reporting name: Fishpot) was a single-engine, all-weather, missile-armed interceptor aircraft developed by the Soviet Union.

Development

Three Su-9 aircraft in 1982

The Su-9 emerged from aerodynamic studies by TsAGI, the Soviet aerodynamic center, during the Korean War, which devised several optimum aerodynamic configurations for jet fighters. The design first flew in 1956 as the T-405 prototype. The Su-9 was developed at the same time as the Su-7 "Fitter", and the West first saw both at the Tushino Aviation Day on June 24, 1956, where the Su-9 was dubbed Fitter-B. It entered service in 1959.

The total production of the Su-9 was about 1,100 aircraft. It is believed that at least some Su-9s were upgraded to Su-11 "Fishpot-C" form. None were exported to any of the USSR's client states nor to the Warsaw Pact nations. The remaining Su-9s and later Su-11s were retired during the 1970s. Some were retained as test vehicles or converted to remote-piloted vehicles for use as unmanned aerial vehicles. It was replaced by the upgraded Su-11 and the much-superior Su-15 "Flagon" and MiG-25 "Foxbat".

The combat record of the "Fishpot" is poorly documented. It is possible that it was involved in the interception (or even shoot-down) of reconnaissance missions, but no information has been publicly declassified.

Being an interceptor, the Su-9 was used in routine patrols and interdictions over the Soviet Frontiers. The most widely known involved in the interception of Francis Gary Powers' U-2 on Soviet territory on May 1, 1960. The Su-9 was unarmed and was directed to ram the U-2. One ramming attempt was made, but the Su-9 missed the U-2 due to the significant difference in the speed of the two planes. Due to the Su-9's lack of fuel, the pilot elected to break away from the U2 and continue with the original flight plan. Its pilot, Captain Igor Mentyukov, later claimed that his slipstream caused the U-2 to break apart. He discounts the official version that the U-2 was shot down by an SA-2 missile, explaining that Powers could not have survived such a hit.

On September 4, 1959 a modified Su-9 (designated T-431 by the bureau) piloted by Vladimir Sergeievitch Ilyushin set a new world record for absolute height, at 28,852 m (94,658 ft). In November of the same year, Ilyushin set several new sustained speed/altitude records in the same aircraft. This record was later broken on December 6, 1959, by Commander Lawrence E. Flint Jr., who performed a zoom climb to a world record of 98,557  feet (30,040 meters) while piloting an F4H-1 Phantom.

Bobrovka became the Soviet Union's primary storage facility for the Su-9 as it was phased out, and by 1981 at least 243 Su-9 aircraft were observed parked at Bobrovka.

Design

Sukhoi Su-9 in Monino museum

The Su-9's fuselage and tail surfaces resembled those of the Su-7, but unlike the swept wing of that aircraft, the "Fishpot" used a 53° delta wing with conventional slab tailplanes. It shared Sukhoi features like the rear-fuselage air brakes as well as the Su-7's Lyulka AL-7 turbojet engine and nose intake. The translating shock cone contains the radar set.

The Su-9 was developed from earlier work on a developmental aircraft designated T-3, to which the Su-9 was nearly identical. Internally at Sukhoi, the Su-9 was known as the T-43.

The delta wing of the Su-9 was adopted because of its lower drag in the supersonic flight regime. Its greater volume also allowed a modest fuel capacity increase compared to the Su-7. The Su-9 was capable of Mach 1.8 at altitude or about Mach 1.14 with missiles. However, its fuel fraction remained minimal, and its operational radius was limited. Furthermore, rotation speeds were even higher than the Su-7, which was already high at 360  km/h (225  mph). Unlike the Su-7, which had cumbersome controls but docile handling characteristics, the "Fishpot" had light and responsive controls but was unforgiving of pilot error.

The Su-9 had primitive R1L (NATO reporting name "High Fix") radar in the shock cone and was armed with four K-5 (AA-1 "Alkali") beam-riding air-to-air missiles. Like all beam-riders, the K-5 was so limited as to be nearly useless for air-to-air combat . Unlike the Su-7 and later Su-15, no Su-9 carried cannon armament, although two fuselage pylons were reserved for the carriage of drop tanks.

A two-seat trainer version designated Su-9U was also produced in limited numbers (about 50 aircraft). It received the NATO reporting name "Maiden." It had a full armament and radar system with displays in both cockpits, allowing trainees to practice all aspects of the interception mission. Still, because the second seat further reduced the already meager fuel fraction, it was not genuinely combat-capable.

The Su-9 has been frequently mistaken for the MiG-21 due to the many similarities in design. The primary distinguishing factors are size and the Su-9's bubble canopy.

Variants

Development of the Su-9.

T-405

Prototype model of the Su-9.

Su-9

Production variant, about 1,100 built.

Su-9U

Training variant, mounting the standard avionics suite without weapon systems or hardpoints. About 50 units were manufactured.

T-431

A specially modified Su-9 for setting the world record for absolute height in 1962.

Sukhoi Su-11

A upgraded design based on the Su-9. It was slightly lengthened compared to the Su-9. However, it was outmoded by the Sukhoi Su-15, which offered vastly increased range and aerodynamic performance.

Sukhoi Su-17

Is the first Sukhoi design to incorporate a Variable-sweep wing. The Su-17 was designed in parallel with the Su-11 but was delayed until the wing-sweeping mechanism was ready. The Su-17 exists in numerous variations and was exported to Warsaw Pact nations and other nations such as Peruvian Air Force .

Operators

Soviet Union

• Soviet Anti-Air Defense

894th Fighter Aviation Regiment, Ozernoye, Ukraine, 1959-1979.

Specifications (Su-9)

Sukhoi Su-9

Data from OKB Sukhoi : a history of the design bureau and its aircraft

General characteristics

• Crew: 1 (Su-9U 2)
• Length: 16.772 m (55 ft 0 in)
• Wingspan: 8.536 m (28 ft 0 in)
• Height: 4.82 m (15 ft 10 in)
• Wing area: 34 m² (370 sq ft)
• Empty weight: 7,675 kg (16,920 lb)
  
• Landing weight: 8,658 kg (19,088 lb)
• Gross weight: 10,755 kg (23,711 lb)
• Max takeoff weight: 12,512 kg (27,584 lb)
• Fuel capacity: 3,100 kg (6,834 lb) internal + 2,160 kg (4,762 lb) in external tanks
• Powerplant: 1 × Lyulka AL-7F-1-100 afterburning turbojet engine, 66.67 kN (14,987 lbf) thrust dry, 94.12 kN (21,158 lbf) with afterburner

Performance

• Maximum speed: 2,120 km/h (1,320 mph, 1,140 kn) / M1.73 at 13,000 m (43,000 ft)

2,230 km/h (1,390 mph; 1,200 kn) over 13,000 m (43,000 ft)

• Landing speed: 305–310 km/h (190–193 mph; 165–167 kn)
• Range: 1,350 km (840 mi, 730 nmi) internals
• Ferry range: 1,800 km (1,100 mi, 970 nmi) with external tanks
• Endurance: 1 hour 18 minutes on internal fuel

2 hours with external tanks

• Service ceiling: 20,000 m (66,000 ft)
• g limits: +7
• Wing loading: 316 kg/m² (65 lb/sq ft)
• Thrust/weight: 0.89
  
• Landing run: 1,150–1,250 m (3,770–4,100 ft) without brake parachute

Armament

• Hardpoints: 2 × under-fuselage hardpoints for drop tanks and 4 × under-wing hardpoints for 500 kg (1,100 lb) of disposable stores with provisions to carry combinations of:
  • Missiles: 4 × K-5 air-to-air missiles

See also

• List of military aircraft of the Soviet Union and the CIS

Related development

• Sukhoi Su-7
• Sukhoi Su-11

Aircraft of comparable role, configuration and era

• English Electric Lightning
• Convair F-106 Delta Dart
• Lockheed F-104 Starfighter
• Dassault Mirage III
• Saab 35 Draken
• Mikoyan-Gurevich MiG-21
• CAC CA-23

External links

• Su-9 from NAPO (Novosibirsk Aircraft Production Association)
• Su-9 from Global Aircraft
• Su-9 from FAS