Mikoyan-Gurevich MiG-23

The Mikoyan-Gurevich MiG-23 (; NATO reporting name: Flogger) is a single-engined, supersonic, variable-sweep wing fighter aircraft, designed by the Mikoyan-Gurevich design bureau in the Soviet Union. It is a third-generation jet fighter, alongside similar Soviet aircraft such as the Su-17 "Fitter". It was the first Soviet fighter to field a look-down/shoot-down radar, the RP-23 Sapfir, and one of the first to be armed with beyond-visual-range missiles. Production started in 1969 and reached large numbers with over 5,000 aircraft built, making it the most produced variable-sweep wing aircraft in history. The MiG-23 remains in limited service with some export customers.

The basic design was also used as the basis for the Mikoyan MiG-27, a dedicated ground-attack variant. Among many minor changes, the MiG-27 replaced the MiG-23's nose-mounted radar system with an optical panel holding a laser designator and a TV camera.

Development

The MiG-23's predecessor, the MiG-21, was fast and agile, but limited in its operational capabilities by its primitive radar, short range, and limited weapons load (restricted in some aircraft to a pair of short-range R-3/K-13 (AA-2 "Atoll") air-to-air missiles). Work began on a replacement for the MiG-21 in the early 1960s. The new aircraft was required to have better performance and range than the MiG-21, while carrying more capable avionics and weapons including beyond-visual-range (BVR) missiles such as the R-23R or its successor, the R-24R, both of them being semi-active radar homing (SARH) missiles. A major design consideration was take-off and landing performance. The Soviet Air Force (VVS) demanded the new aircraft have a much shorter take-off run. Low-level speed and handling was also to be improved over the MiG-21. Manoeuvrability was not an urgent requirement. This led Mikoyan to consider two options: lift jets, to provide an additional lift component; and variable-geometry wings, which had been developed by TsAGI for both "clean-sheet" aircraft designs and adaptations of existing designs. thumb|upright=0.8|left|A Polish MiG-23MF

The first option, for an aircraft fitted with lift jets, resulted in the "23-01", also known as the MiG-23PD (' – lift jet), was a tailed delta of similar layout to the smaller MiG-21 but with two lift jets in the fuselage. This first flew on 3 April 1967, but it soon became apparent that this configuration was unsatisfactory, as the lift jets became useless dead weight once airborne. Work on the second strand of development was carried out in parallel by a team led by A.A Andreyev, with MiG directed to build a variable-geometry prototype, the "23-11" in 1965.

thumb|MiG-23 parkedThe 23-11 featured variable-geometry wings which could be set to angles of 16, 45 and 72 degrees, and it was clearly more promising. The maiden flight of 23–11 took place on 10 June 1967, flown by the famous MiG test pilot Aleksandr Vasilyevich Fedotov. Six more flight prototypes and two static-test prototypes were prepared for further flight and system testing. All featured the Tumansky R-27-300 turbojet engine with a thrust of 77 kN (17,300 lbf). The order to start series production of the MiG-23 was given in December 1967. The first production "MiG-23S" (NATO reporting name 'Flogger-A') took to the air on 21 May 1969, with Fedotov at the controls.

The General Dynamics F-111 and McDonnell Douglas F-4 Phantom II were the main Western influences on the MiG-23. The Soviets, however, wanted a much lighter, single-engined fighter to maximize agility. Both the F-111 and the MiG-23 were designed as fighters, but the heavy weight and inherent stability of the F-111 turned it into a long-range interdictor and kept it out of the fighter role. The MiG-23's designers kept the MiG-23 light and agile enough to dogfight with enemy fighters.

Design

Armament

The armament carried by the MiG-23 changed as new models underwent development. The initial production variant, the MiG-23S, was fitted with the S-21 fire control system borrowed from the MiG-21S/SM. Based on the RP-22SM Sapfir-21 radar with an ASP-PFD-21 lead computing gunsight, it could carry only four R-3/K-13 (AA-2 "Atoll") air-to-air missiles (typically two SARH R-3Rs and two IR R-3Ss) in addition to a Gryazev-Shipunov GSh-23L autocannon. In the ground-attack role, the MiG-23S could carry two Kh-23 (AS-7 "Kerry") radio guidance air-to-surface missiles, two to four UB-16 rocket pods with S-5 rockets, S-24 rockets or up to of various bomb types. The MiG-23 Edition 1971, equipped with the Sapfir-23L radar and TP-23 infrared search and track (IRST), could fire the new BVR R-23 (AA-7 "Apex") missile, although only the R-23R SARH variant. However, the Sapfir-23L was considered unreliable and lacked look-down/shoot-down capability. The MiG-23 could carry up to in bombs and rockets, and from aircraft number 3701 onward it could fire the Kh-23 and Kh-23M air-to-surface missiles. Lastly, all VVS MiG-23Ms had the ability to mount a single nuclear bomb via a special adapter under the fuselage, either the 10-kiloton RN-24 or the 30-kiloton RN-40. The final fighter variant, the MiG-23MLD, could also carry the improved R-24R/T missiles in addition to a pair of B8M1 20-round rocket pods firing S-8 rockets, the Kh-23/Kh-23M air-to-surface missile, or a single RN-24 or RN-40 nuclear bomb. The MiG-23MLD's maximum bomb load was , with a standard loadout comprising four FAB-500 general-purpose bombs (GP) or ZAB-500 napalm bombs. Other configurations included sixteen FAB-100 GP bombs carried on four ejector racks, four FAB-250 GP bombs, or two RBK-500 cluster bombs.

Starting with the MiG-23 Edition 1971, the MiG-23 replaced the head-down radar scope with an ASP-23D gunsight/head-up display (HUD) onto which data from the radar was displayed. Israeli pilots who flew captured versions of the MiG-23 found it relatively easy to use.

thumb|left|MiG-23 wing-sweep mechanism

The wings were not fitted with ailerons but used spoilers to control rolling when the wings were at 16° and 45° angles. In addition to the spoilers, the wings were fitted with trailing edge flaps and leading edge slats to try to give the fighter a short take-off and landing performance.

Two tailerons controlled pitch and roll, in the latter case working in conjunction with wing control surfaces when the wings were not fully swept back. In addition to a large vertical stabilizer (which also stored the brake parachute for landings), the MiG-23 had a ventral fin to improve directional stability at high speeds. During take-off and landing, the fin hinged sideways when the landing gear was extended to prevent it striking the ground. The definitive Edition 3 wing design, introduced with the MiG-23M, retained the dimensions of the Edition 2 but added back in the leading-edge slats.

Engine

The MiG-23's original engine was a thrust Tumansky R-29-300 with thrust to spare at the aircraft top speed of Mach 2.4. It also had a fast acceleration time, taking 3–4 seconds to go from idle to full power, and took less than a second to ignite the afterburner. The engine intake had louvers which supplied the environmental control system with air to keep the avionics and pilot cool. This was partly because Russian engines were designed to last about 150 hours before being replaced. Changing an engine was difficult because the aircraft had to be separated in the middle. The MiG-23 Edition 1971 redesign allowed for a fourth tank carrying to be fitted in the rear of the fuselage. Introduced with the MiG-23M were plumbed pylons under the movable wing panels which could be fitted with drop tanks, though these could only be carried with the wings at full spread and had to be jettisoned otherwise, and a third 800-liter drop tank could be carried under the fuselage on the MiG-23ML. Additionally, a Cuban pilot flew a MiG-23BN to the U.S. in 1991, and a Libyan MiG-23 pilot also defected to Greece in 1981. In both cases, the aircraft were later repatriated.

Initially, American intelligence on the MiG-23 assumed that the fighter could turn well and had reasonable acceleration capability, but testing during HAVE PAD proved this assumption to be incorrect. While its turning capability was comparable to an original F-4E Phantom, newer American fighters like the F-15 Eagle or F-4E upgraded with slats could easily out-turn the MiG-23 in a dogfight. In fact, whenever the MiG-23 approached high angle of attack it became very unstable and liable to depart controlled flight. Conversely, the MiG-23's acceleration capability was tremendous, particularly at low altitudes (below ) and crossing the sound barrier, where it could out-accelerate any American fighter.

The MiG-23's deficits and qualities were also recognized by allied air forces which received the fighter from the Soviet Union, including the East German Air Force: