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Swing Wing Suhkoi

by Chris Banyai-Riepl

The concept of the swing wing in not new. Research dating back to the second world war can be found. The NATO countries researched it thoroughly, culminating in such planes as the B-1B, the F-14, the Tornado, and the F-111. On the other side of the Cold War, swing wing research was carried out as well, with much more plentiful results. Tupelov designed several swing wing bombers, including the Backfire and Blackjack bombers. On the fighter front, it was Suhkoi that pursued the swing wing concept, with no less than three designs incorporating swing wings, the final one being the Su-24 "Fencer".

The Su-24 got its start back in 1968 with the T6 test aircraft. The T6 originally incorporated lift jets and had a triangular wing, but with the appearance of the US F-111, political pressure was put on to produce a comparable aircraft. So the second T6 airframe replaced the triangular wing with a swing wing and removed the lift jets altogether. This testbed first flew in January of 1970 was then designated Su-24. Production started in 1972 and replaced the assembly line of Su-15TM interceptors, with the first Su-24 delivery taking place in late 1974.

The test program for the Su-24 was very drawn out. Because of the technically advanced electronics and airframe, it was determined in 1973 that a further 1200 test flights were needed to complete the test phase. This would have extended the test program an additional 2 years, which greatly angered the head of the VVS. After discussions with the head of the air industry, the test program was closed in September 1974, with several items left undiscovered, such as the maximum ceiling and the maximum speed at high altitudes. It was determined that this information was not really needed for a low altitude tactical bomber.

The arrangement of the Su-24 is very similar to that of the General Dynamics F-111, with two crew members sitting side by side. Each crew member sat in the K-36D ejection seat, making it the first Soviet plane to incorporate a zero-zero ejection seat. Each seat ejects in a different direction to avoid collisions during the ejection process. This is different than in the F-111, in which the entire cockpit section is ejected. Each pilot has a full set of controls and either one can fly the plane. The fuselage has a rectangular cross section, which makes the use of large body panels possible. The wing could swing from 16° for takeoff and landing to 35° for subsonic cruising to 45° for combat maneuvering to 69° for high speed supersonic flight. The stabilizer is of the all-moving slab type. The most prominent feature of the Su-24 is that of most Soviet jets and that is a very large nose which houses the powerful pulse-Doppler and fire control radar.

The armament of the Su-24 is carried externally on eight stations: four on the wings and four under the fuselage. Depending on the mission, some or all of these stations could be filled. Each station could carry bombs from 100kg to 1500kg, rocket pods containing all types from 57mm to 370mm, or cluster bombs. A 23mm rotary gun capable of 10,000 rounds per minute is installed on the lower midsection. Additionally, three more of this type of gun could be installed in pods with each pod aligned independently aligned, resulting in a huge coverage by all four guns.
For the anti-radar "Wild Weasel" mission, two heavy Kh-28 missiles were carried on wing pylons. This was a very accurate missile with a range of over 90km.
It suffered from poor serviceability, though, due to its toxic liquid fuel. Self defense fell to the standard heat seeking missiles such as the R-13M or R-60, four of which could be carried.

Because of the protracted development cycle and longer than normal test cycle, almost as soon as the Su-24 entered service an upgrade program was started. This was due to changes anti-aircraft systems coming into service in the US and NATO countries. This new, updated Su-24 became the Su-24M. The Su-24M incorporated a new navigation and fire control radar, making it much more versatile and potent. The main differences were higher accuracy in bombing missions, the ability to aim guided bombs, and more accurate gun targeting. The navigation system allowed the Su-24M to fly along a preprogrammed course and fly an automatic return in all weather at altitudes as low as 40 meters. The Wild Weasel mission got a boost as well, with the replacement of the Kh-28 with the newer Kh-58, which used a simpler solid fuel propellant and thus had a higher serviceability rate. The Su-24M could also carry the Kh-31P, which is a high speed ARM capable of taking out the US Patriot system.
Other weapons of the Su-24M arsenal include several different TV-guided weapons, such as the Kh-29 (similar to the US AGM-65 Maverick), the Kh-59M (similar to the US AGM-142), and the KAB-500Kr, a TV guided bomb. Laser guided bombs can also be carried. This weapon capability, coupled with in-flight refueling (the first Soviet tactical bomber so equipped) makes the Su-24M a very potent machine, easily the equivalent to the US F-111 or the NATO Tornado.

Proving its capabilities was not long in coming, either. The Su-24 found its way into several different air forces, including Iraq, Iran, Libya, Algeria, and Syria, as well as many of the independent states following the collapse of the Soviet Union. The Su-24 also saw action in Afghanistan, serving alongside antiquated Tu16 bombers. Because of the lack of high altitude AA weapons, and the large amount of low to medium altitude AA weapons possessed by the Afghan rebels, the Su-24s did not utilize their excellent low level performance, but rather stayed out of range of the anti-aircraft systems and delivered their weapons from altitudes over 5500 meters. Even still the results were devastating, with the Su-24s destroying several hundred rebels and forcing the rest to leave their area of operations.

After the breakup of the Soviet Union, most of the older planes such as the MiG-21, MiG-23, MiG-27, and Su-17 were phased out, leaving the Su-24 as the main fighter bomber of the new Russian air force. As the Russian economy became more and more pinched, the operational status of the air force fell. Much faith was placed on the air-to-air refueling capabilities of the Su-24 and its ability to fly halfway around the world and still perform its mission. This was demonstrated to great effect by 10 Su-24s flew from the Russian European regions to the Far East and successfully performed the simulated mission. Even in the hard times of the Russian military, the Su-24 could still perform. Then, in the winter of 1994 and 1995, the Su-24 once again entered combat, this time against military units in Chechnya. With shades similar to Desert Storm, Su-24s used laser and optically guided munitions against bunkers and hardened structures, destroying several. With the fighting taking place in the middle of winter, fog and snow prevented other aircraft and helicopters from doing their mission, but the all weather capabilities of the Su-24 allowed it to carry out their missions without any worries and still maintain a high level of precision.

With the Russian VVS downsizing and focusing on quality weapon delivery systems instead of quantity, the Su-24 will remain in its arsenal for many years to come. The capability of placing munitions precisely is essential in today's warfare, and the Su-24 does this admirably. Other countries have seen this, and such places as the Ukraine will keep their fleet in service for a long time as well. The Iraqi Su-24s were actually some of the few planes to escape to Iran, utilizing the excellent low level flight characteristics of the Su-24 to evade coalition fighters. Overall, the Su-24 is a tribute to Pavel Suhkoi's vision, as this 30 year old plane performing in today's world shows.

The Aircraft of Pavel Suhkoi Part Two: Jets, the Payoff, Geo. John Geiger, Air Combat Volume 5 Number 6, November 1977.

Fencers in Germany, Kieron Pilbeam, Air Forces Research No. 6, September 1995.

SU-24 Tactical Bomber, V. Ilyin, J. Martinek, V. Rudyenko, J. Stepán, Zlinek No. 2 Volume III.