Sukhoi Su-24

The Sukhoi Su-24 (NATO reporting name: Fencer) is a supersonic, all-weather attack aircraft developed in the Soviet Union. This variable-sweep wing, twin-engined side-by-side two-seater carried the USSR's first integrated digital navigation/attack system. It remains in service with former Soviet air forces and various air forces to which it was exported.

Background
One of the conditions for accepting Sukhoi Su-7B into service in 1961 was the requirement for Sukhoi to develop an all-weather variant capable of precision air strikes. Preliminary investigations with S-28 and S-32 aircraft revealed that the basic Su-7 design was too small to contain all the avionics required for the mission. OKB-794 was tasked with developing an advanced nav/attack system, codenamed Puma, which would be at the core of the new aircraft.

In 1962-1963, Sukhoi designed and built a mockup of S-6, a delta wing aircraft powered by two Tumansky R-21F-300 turbojet engines and with a crew of two in a tandem arrangement. The mockup was inspected but no further work was ordered due to lack of progress on the Puma hardware.

In 1964, Sukhoi started work on S-58M. The aircraft was supposed to represent a modification of the Sukhoi Su-15 interceptor (factory designation S-58). In the meantime, revised Soviet Air Force requirements called for a low-altitude strike aircraft with STOL capability. A key feature was the ability to cruise at supersonic speeds at low altitude for extended periods of time in order to traverse enemy air defenses. To achieve this, the design included two Tumansky R-27F-300 afterburning turbojets for cruise and four Kolesov RD-36-35 turbojets for STOL performance. Side-by-side seating for the crew was implemented since the large Orion radar antennae required a large frontal cross-section. To test the six-engine scheme, the first Su-15 prototype was converted into S-58VD flying laboratory which operated in 1966-1969.

Design phase


The aircraft was officially sanctioned on 24 August 1965 under the internal codename T-6. The first prototype, T-6-1 was completed in May 1967 and flew on 2 July with V.S. Ilyushin at the controls. The initial flights were performed without the four lift engines, which were installed in October 1967. At the same time, R-27s were replaced with Lyulka AL-21Fs. STOL tests confirmed the data from S-58VD that short-field performance was achieved at the cost of significant loss of flight distance as the lift engines occupied space normally reserved for fuel, loss of under-fuselage hardpoints, and instability during transition from STOL to conventional flight. So the six-engine approach was abandoned.

On 7 August 1968, the OKB was officially tasked with investigating a variable geometry wing for the T-6. The resulting T-6-2I first flew on 17 January 1970 with Ilyushin at the controls. The subsequent government trials lasted until 1974, dictated by the complexity of the on-board systems. The day or night and all-weather capability was achieved - for the first time in Soviet tactical attack aircraft - thanks to the Puma nav/attack system consisting of two Orion-A superimposed radar scanners for nav/attack, a dedicated Relyef terrain clearance radar to provide automatic control of flights at low and extremely low altitudes, and Orbita-10-58 onboard computer. The crew was equipped with zero-zero Zvezda K-36D ejection seats, allowing the pilots to bail out at any altitude and flight speed, including during takeoff and landing.



The first production aircraft flew on 31 December 1971 with V. T. Vylomov at the controls, and on 4 February 1975, T-6 was formally accepted into service as the Su-24. About 1,400 Su-24s were produced.

Upgrades
Surviving Su-24M models gone through a life-extension and updating program, with GLONASS, upgraded cockpit with multi-function displays (MFDs), HUD, digital moving-map generator, Shchel helmet-mounted sights, and provision for the latest guided weapons, including R-73 (AA-11 'Archer') air-to-air missiles. It is unclear if the Su-24MR and Su-24MP will receive the cockpit and navigation upgrades. The upgraded aircraft are designated Su-24M2.

Design


The Su-24 has a shoulder-mounted variable geometry wing outboard of a relatively small fixed wing glove, swept at 69°. The wing has four sweep settings: 16° for take-off and landing, 35° and 45° for cruise at different altitudes, and 69° for minimum aspect ratio and wing area in low-level dashes. The variable geometry wing provides excellent STOL performance, allowing a landing speed of 230 km/h (143 mph), even lower than the Sukhoi Su-17 despite substantially greater take-off weight. Its high wing loading provides a stable low-level ride and minimal gust response.

The Su-24 has two Saturn/Lyulka AL-21F-3A afterburning turbojet engines with 109.8 kN (24,700 lbf) thrust each, fed with air from two rectangular side mounted intakes with splitter plates/boundary-layer diverters.

In early Su-24 ("Fencer A" according to NATO) aircraft these intakes had variable ramps, allowing a maximum speed of 2,320 km/h (1,440 mph), Mach 2.18, at altitude and a ceiling of some 17,500 m (57,400 ft). Because the Su-24 is used almost exclusively for low-level missions, the actuators for the variable intakes were deleted to reduce weight and maintenance. This has no effect on low-level performance, but absolute maximum speed and altitude are cut to Mach 1.35 and 11,000 m (36,100 ft). The earliest Su-24 had a box-like rear fuselage, which was shortly changed in production to a rear exhaust shroud more closely shaped around the engines in order to reduce drag. The revised aircraft also gained three side-by-side antenna fairings in the nose, a repositioned braking chute, and a new ram-air inlet at the base of the tail fin. The revised aircraft were dubbed "Fencer-B" by NATO, but did not merit a new Soviet designation. The Su-24's fixed armament is a single fast-firing GSh-6-23 cannon with 500 rounds of ammunition, mounted in the fuselage underside. The gun is covered with an eyelid shutter when not in use. The warload include various nuclear weapons. Two or four R-60 (NATO AA-8 'Aphid') infrared missiles are usually carried for self-defense by the Su-24M/24MK.

Initial Su-24s had basic electronic countermeasures (ECM) equipment, with many Su-24s limited to the old Sirena radar-warning receiver with no integral jamming system. Later-production Su-24s had more comprehensive radar warning, missile-launch warning, and active ECM equipment, with triangular antennas on the sides of the intakes and the tip of the vertical fin. This earned the NATO designation "Fencer-C", although again it did not have a separate Soviet designation. Some "Fencer-C" and later Su-24M ("Fencer-D" by NATO) have large wing fence/pylons on the wing glove portion with integral chaff/flare dispensers; others have such launchers scabbed onto either side of the tail fin.

Operational history
Substantial numbers of ex-Soviet Su-24s remain in service with Azerbaijan, Kazakhstan, Russia, Uzbekistan and Ukraine. In 2008, roughly 415 were in service with Russian forces, split 321 with the Russian Air Force and 94 with the Russian Navy.

On 19 December 2008, a Su-24M crashed near the southwest Russian city of Voronezh. The pilots ejected. Preliminary information indicates the crash was caused by a malfunction in the aircraft's flight control system.

On 13 February 2012, a Su-24 crashed in Kurgan region. Both pilots ejected safely. Engine failure was stated as the probable cause of the crash.

On 30 October 2012, a Su-24M crashed in Chelyabinsk Oblast, Russia. During the flight that the nose cone became broken. After unsuccessful try in emergency landing, crew of two flew to safe territory and ejected. No reported fatalities. A regional government website stated that emergency was result of aircraft control system failure. Flights of Su-24 was suspended at Shagol base.

The Russian Air Force considers eventually replacing the Su-24 with the Sukhoi Su-34.

Soviet War in Afghanistan
The Soviets used some Su-24s in Afghanistan starting from 1984.

Operation Desert Storm
During Operation Desert Storm, the Iraqi Air Force evacuated 24 of its 30 Su-24MKs to Iran. Another five were destroyed on the ground, while the sole survivor remained in service after the war.

Second Chechen War
Su-24s were used in combat during the Second Chechen War performing bombing and reconnaissance missions. Up to four were lost, one due to hostile fire.

On 4 October 1999, a Su-24 was shot down by a SAM while searching for the crash site of a downed Su-25. The pilot was killed while the navigator was taken prisoner.

2008 South Ossetia War
In August 2008, a low intensity conflict in the breakaway Georgian regions of Ossetia and Abkhazia, escalated to open war between Russia and Georgia. Russian Su-24s were heavily involved in bombing strikes and reconnaissance flights over Georgia.

Libyan civil war
During the 2011 Libyan civil war, on 5 March 2011, rebels shot down a Libyan Air Force Su-24MK during fighting around Ra's Lanuf with a ZU-23-2 antiaircraft gun. Both pilots died. A BBC reporter was on the scene soon after the event and filmed an aircraft part at the crash site showing the emblem of the 1124th squadron, flying the Su-24MK.

Syrian Civil War
During the escalation of the Syrian Civil War, starting in November 2012, around two months after the first air raids from different fixed wing aircraft started and after 18 months since the beginning, the first Su-24 medium bombers were filmed dropping their heavy payload on the rebels.

Variants

 * Source: Sukhoi 


 * S6
 * An early project in the gestation of the Su-24, like a meld of the Su-7 and Su-15.


 * T6-1
 * The initial prototype with cropped delta wings and 4 RD-36-35 lift engines in the fuselage.


 * T6-2I / T6-3I / T6-4I;
 * Prototypes for the variable geometry Su-24 production aircraft.


 * Su-24
 * The first production version, the armaments include Kh-23 and Kh-28 type air-to-ground guided missiles, together with R-55 type air-to-air guided missiles. Manufactured 1971-1983.


 * Su-24M ('Fencer-D')
 * Work on upgrading the Su-24 was started in 1971, and included the addition of inflight refueling and expansion of attack capabilities with even more payload options. T-6M-8 prototype first flew on 29 June 1977, and the first production Su-24M flew on 20 June 1979. The aircraft was accepted into service in 1983. Su-24M has a 0.76 m (30 in) longer fuselage section forward of the cockpit, adding a retractable refueling probe, and a reshaped, shorter radome for the attack radar. It can be identified by the single nose probe in place of the three-part probe of earlier aircraft. A new PNS-24M inertial navigation system and digital computer were also added. A Kaira-24 laser designator/TV-optical quantum system (similar to the American Pave Tack) was fitted in a bulge in the port side of the lower fuselage, as well as Tekon track and search system (in pod), for compatibility with guided weapons, including 500 and 1,500kg laser-guided bombs and TV-guided bombs, and laser/TV-guided missiles Kh-25 and Kh-29L/T, anti-radar missiles Kh-58 and Kh-14 (AS-12 'Kegler') and Kh-59 (AS-13 'Kingbolt')/Kh-59M TV-target seeker guided missiles. The new systems led to a reduction in internal fuel amounting to 85 l (22.4 US gal). Su-24M was manufactured in 1981-1993.


 * Su-24M2 ('Fencer-D')
 * Next modernization of Su-24M introduced in 2000 with the “Sukhoi” program and in 1999 with the “Gefest” program. The modernized planes are equipped with new equipment and systems. As a result, they get new capabilities and improved combat efficiency, including new navigation system (SVP-24), new weapons control system, new HUD (ILS-31, like in Su-27SM or KAI-24) and expanding list of usable munitions (Kh-31A/P, Kh-59MK, KAB-500S). The last batch of the sukhoi was delivered to the Russian VVS in 2009. Modernization continues with the program “Gefest”. All frontline bombers Su-24 in the Central Military District (CVO) received new sighting and navigation systems SVP-24 in 2013.


 * Su-24MK ('Fencer-D')
 * Export version of the Su-24M with downgraded avionics and weapons capabilities. First flight 30 May 1987 as T-6MK, 17 May 1988 as Su-24MK. Manufactured 1988-1992, sold to Algeria, Iran, Iraq, Libya, and Syria.


 * Su-24MR ('Fencer-E')
 * Dedicated tactical reconnaissance variant. First flight 25 July 1980 as T-6MR-26, 13 April 1983 as Su-24MR. Entered service in 1983. Su-24MR retains much of the Su-24M's navigation suite, including the terrain-following radar, but deletes the Orion-A attack radar, the laser/TV system, and the cannon in favor of two panoramic camera installations, 'Aist-M' ('Stork') TV camera, RDS-BO 'Shtik' ('Bayonet') side-looking airborne radar (SLAR), and 'Zima' ('Winter') infrared reconnaissance system. Other sensors are carried in pod form. Manufactured 1983-1993.


 * Su-24MP ('Fencer-F')
 * Dedicated electronic signals intelligence (ELINT) variant, intended to replace the Yak-28PP 'Brewer-E'. First flight 14 March 1980 as T-6MP-25, 7 April 1983 as Su-24MP. The Su-24MP has additional antennas for intelligence-gathering sensors, omitting the laser/TV fairing, but retaining the cannon and provision for up to four R-60 (AA-8) missiles for self-defense. Only 10 were built.

Operators

 * : Algerian Air Force 34 Su-24MK, some upgraded to the M2 standard. 2 Su-24MR.
 * 🇦🇿: 11, 5 in active service with the Azerbaijan Air Force as of November 2008.
 * 🇮🇷: 24 to 36 are in service with the Islamic Republic of Iran Air Force after the Iran-Iraq war. 24 Iraqi Su-24s were evacuated to Iran during the Gulf War and were put in service with the IRIAF. Possibly Iran purchased other Su-24s from Russia or other former Soviet States. Iran tested domestically produced anti-radar smart missiles carried by Su-24 in September 2011. The IRIAF's Deputy Commander, General Mohammad Alavi said, IRINN TV reported during the tests.
 * 🇰🇿: 25 in service with the military of Kazakhstan
 * Russian Air Force - 251 Su-24M, 40 Su-24M2, 79 Su-24MR
 * Russian Naval Aviation - 51 in service
 * 🇸🇾: Reports of as many as 20 in service with the Syrian Air Force
 * 🇺🇦: 120 Su-24, 25 in service, 95 on the conservation.
 * : Up to 12 ex Belarusian Air Force were transferred to Sudan in 2013 together with ground support
 * : Up to 12 ex Belarusian Air Force were transferred to Sudan in 2013 together with ground support

Former

 * 🇮🇶 Iraq: 30 delivered to the Iraqi Air Force, five destroyed in the Persian gulf war, one survived in Iraq and 24 flew to Iran where they were pressed into service for the IRIAF;
 * Libyan Arab Jamahiriya: 6 Su-24MKs purchased for the Libyan Air Force. One destroyed in fire, one shot down in 2011. Other destroyed on Libyan Air Force airfield Ghardabiya after by coalition aircraft in 20 March 2011.
 * : Passed on to successor states.
 * Soviet Air Force
 * Soviet Naval Aviation
 * 🇧🇾: Inherited from the Soviet Union, 34 served with the Belarusian Air Force, consisting of 22 Su-24Ms and 12 Su-24MRs. All retired from Belarusian service in 2012 with up to 12 transferred to Sudan in 2013 together with ground support.
 * 🇧🇾: Inherited from the Soviet Union, 34 served with the Belarusian Air Force, consisting of 22 Su-24Ms and 12 Su-24MRs. All retired from Belarusian service in 2012 with up to 12 transferred to Sudan in 2013 together with ground support.