The Sukhoi Su-24 (NATO reporting name Fencer) emerged from an early 1960s specification for a new attack bomber to replace the Ilyushin Il-28 and Yakovlev Yak-28.
The specification called for an all-weather aircraft capable of supersonic speed at low level, with a very high standard of navigational and bombing accuracy and a excellent short-field performance.
A solution was variable geometry, also being applied to the roughly contemporary Sukhoi Su-17 and Mikoyan-Gurevich 23-11.
The second Sukhoi prototype was fitted with a variable wing, redesignated T-6-2IG.
This first flew in 1970, and proved to be successful enough to merit production, initially under a cover designation of Su-15M .
The Su-24 evolved through several early variations, each earning separate NATO reporting names.
The Su-24M finally entered service in 1983. Two specialized versions, the Su-24MR ('Fencer-E') reconnaissance variant and the Su-24MP ('Fencer-F') ELINT gatherer, were developed from the Su-24M.
The Soviets used some Su-24s in Afghanistan in 1984, and the 'Fencer' saw combat service again in the Chechen conflicts of the 1990s.
Its bombing accuracy in the latter conflict has been criticized, because while the Su-24 apparently performed within its original design parameters, there were large numbers of civilian casualties and collateral damage.
An export version of the Su-24M, the Su-24MK, has been sold to several foreign customers. Ten were sold to Algeria, 15 to Libya, and 12 to Syria. A total of 32-33 Su-24MKs were sold to the Islamic Republic of Iran Air Force and to Iraq, but sources differ on the specific numbers. Russian sources claim that nine were sold to Iran and 24 to Iraq, all of which are now operated by Iran. Iran claims it purchased 14 and gained 16-18 ex-Iraqi aircraft that fled Iraq to escape destruction in the 1991 Gulf War.
About 1,200 Su-24s were produced. Substantial numbers of Ex-Soviet Su-24s remain in service with Azerbaijan, Belarus, Kazakhstan, Russia, Uzbekistan and Ukraine. Roughly 577 are currently operational with Russian forces, split 447 with the Russian Air Force and 130 with the Russian Navy.
The Su-24 is aerodynamically similar to the contemporary MiG-23 'Flogger,' although it is substantially larger. It 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 Su-17 despite substantially greater take-off weight.
Its high wing loading provides a stable low-level ride and minimal gust response, but reportedly makes the aircraft somewhat difficult to fly. The Su-24 can be unforgiving under some circumstances.
The Su-24 seats two, a pilot and a weapon systems officer, in side-by-side cockpit (similar to the F-111). The avionics were the most sophisticated in Soviet use, with the USSR's first integrated, and computerized nav/attack system. The early Su-24s carried separate attack and terrain-avoidance radars, along with a Doppler navigation set.
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.
Unlike the MiG-27's external cannon gondola, the 'Fencer' installation of this weapon covers the gun with an eyelid shutter when not in use.
There are eight external hardpoints (two under the inner wing glove, two swiveling pylons under the outer wing, and four on the fuselage) for a maximum warload of 8,000 kg (17,600 lb), including various nuclear weapons.
Two or four R-60 (NATO AA-8 'Aphid') infrared missiles are usually carried for self-defense.
The Su-24 has often been compared to the American F-111, but despite being close to the F-111 in size, it never matched the USAF aircraft's range or load-carrying ability.
Its true capabilities are closer to those of the smaller Panavia Tornado, although its less-efficient engines make the 'Fencer's' range somewhat shorter.
An upgraded 'Fencer' began development in the mid-1970s and entered service around 1983, has a 0.76 m (30 in) longer fuselage section forward of the cockpit, adding a retractable inflight refueling probe, and a reshaped, shorter radome for the new 'Orion-A' attack radar.
It can be identified by the single nose probe in place of the three-part probe of earlier aircraft. The new radar was coupled with a Relyef terrain-following radar coupled with SAU-6M1 automatic flight control system, allowing automatic ("hands-off") low-level flight.
A new PNS-24M inertial navigation system and digital computer were also added. A Kaira 24 laser designator/TV system (similar to the American Pave Tack) was fitted in a bulge in the port side of the lower fuselage for compatibility with guided weapons, including laser-guided bombs and TV-guided bombs, and Kh-14 (AS-12 'Kegler') and Kh-59 (AS-13 'Kingbolt') missiles, as well as unguided bombs and rockets.
The new systems led to a reduction in internal fuel amounting to 85 litres (22.4 US gallons).
Length: 22.67 m (80 ft 6 in)
Saturn/Lyulka AL-21F-3A turbojets, 75 kN dry, 110 kN afterburning (16,900 lbf / 24,700 lbf) each