Variable Sweep Aircraft
Westland-Hill Pterodactyl IV
The Westland-Hill Pterodactyl IV was the 4th of a series of tailless aircraft designed in the UK during the 1930s. Its wings had a variable sweep of 4.75 degrees to adjust the trim of the aircraft due to the lack of a horizontal stabilizer. It doesn't really count as a typical variable sweep design due to the extremely limited sweep and for the sweep having a completely different purpose.
Bell X-5
The Bell X-5 was a prototype demonstration jet for NASA and was the first aircraft capable of changing the sweep of its wings while it was inflight. The design was based on the P.1101 Nazi fighter. The X-5 had three sweep angles: 20*, 40*, and 60* and could change its sweep within 30 seconds . The design however was aerodynamically unstable and could lead to an uncontrollable and unrecoverable spin. These problems dashed the planes of it becoming a low cost fighter for American and its allies. Only two prototypes were built and the program ended on a bad note, however there was enough promise to further develop Variable Sweep technology.
Vickers Swallow
The Vickers Swallow was a supersonic aircraft project by Vickers-Armstrongs. The plane was controlled entirely by the movement of the wing, known as an Aerodyne. Several remotely piloted vehicles were flown to test the aerodynamics. A full scale aircraft was envisioned as either a long range airliner or as a replacement for the Vickers Valiant V-Bomber. The project was cancelled in 1957 following withdrawal of government funding.
F-111 Aardvark
The F-111 was the first variable geometry aircraft to enter production and enter service with the military along with several other new technologies that later became commonplace like variable sweep, afterburning turbofan engines, and terrain-following radar to name a few. There were several roles it was intended to be used for but those were later cancelled due to lingering issues. One of those variants being the F-111B naval defense fighter. It saw service with the US from 1967-1998 and with Australia from 1973-2010, from Vietnam to Desert Storm. It served as a medium range interdictor, tactical attack aircraft, strategic nuclear bomber, aerial reconnaissance, and electronic warfare aircraft.
Mirage G
The Mirage G was a French variable sweep prototype fighter built by Dassault Aviation in 1967 and was the first French variable sweep aircraft. The aircraft was a multi role fighter capable of both interception and nuclear strike missions. Only one prototype was built before the original program was cancelled in 1968 and actually ended when the initial prototype crashed in 1971. Despite the program being cancelled, Dassault continued work on the design and later produced two additional prototypes with the name G-8. The program was born from the need to have a modern high speed fighter capable of both land and aircraft carrier capabilities. The initial prototype only had a single engine in it but the second and third prototypes had a twin engine setup. The design was basically a swing wing version of the Mirage F2 with a wing sweep between 22 and 70 degrees. Despite the success of both prototype models, the design never saw production.
Tu-22 Backfire
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The Tu-22M Backfire is a Soviet long range, supersonic, variable geometry, strategic strike bomber developed in the 1960’s for the Soviet Air Forces in a long range bomber and missile carrier role and for the Soviet Naval Aviation in long range anti-shipping roles. This aircraft has seen significant service in the Soviet armed forces and still serves in the Russian military in significant numbers today with up to 100 still in use. The development of this aircraft was born in the dissatisfaction with the new Tu-22 in 1962 and immediately began work on upgrading the design. The new upgrades involved the addition of a variable geometry wing along with the introduction of newer avionics and engines, to the point that when the work was done it was almost a totally new design. It was marketed as an upgrade though to avoid criticism and to protect the company from embarrassment about the failure of the just introduced Tu-22. There were a total of 497 Tu-22M Backfires produced. The Tu-22M had four wing sweep angles: 20, 30, 50, and 60 degrees. The Tu-22M has proven its capabilities and will continue to do so for the foreseeable future.
Mig-27 Flogger-D/J
The Mig-27 is a variable sweep ground attack aircraft created for the Soviet Union and other export countries. The design was heavily based off of the Mig-23 fighter but modified specifically for ground attack and didn't see much use outside of Russia and India with many countries going for the Mig-23BN (Ground attack focused variant of the fighter) or the Su-22. The only country that continues to use them is Kazakhstan with Russia, India, and Ukraine having retired them from use. Ironically the Mig-27 program was created out of dissatisfaction with the Mig-23BN variant. The differences were a stronger and more simplified airframe, removal of the radar for greater vision for the pilot, a laser range finder, a marked target seeker, and a completely new attack system. With the aircraft being designed for low flight only, much of the complex engine intake and exhaust systems were removed and replaced with simplified fixed systems.
Panavia Tornado
The Panavia Tornado is a family variable sweep multirole fighter jointly developed by Great Britain, Italy, and West Germany. There are three main variants of the Tornado: the fighter bomber strike variant, the electronic warfare and reconnaissance variant, and the interceptor air defense variant. The multirole design of the aircraft allowed it to replace several fleets of separate aircraft which reduces operating and training costs. The program was born after each country (GB, Italy, and Germany) had each cancelled a domestic program and still needed new aircraft to replace the old fleets. From the beginning variable sweep was always going to be part of the design, and after Britain and Germany argued over the seat number it was eventually finalized to a two seater. This program would be like any other normal design, this program would require each country designing and producing different parts of the aircraft all while keeping costs from skyrocketing. After nine prototypes were built and tested, the aircraft entered production in 1976 and stayed until 1998 with 990 aircraft built. The Tornado was retired from British service in 2019 and remains in service with Germany, Italy, and Saudi Arabia (the only export nation of the Tornado). It is likely that all Tornados in service will be retired by the year 2025.
Tu-160 Blackjack
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The Tu-160 Blackjack or White Swan is a variable sweep supersonic strategic heavy bomber designed for the Soviet Union. It is the largest and heaviest bomber/ combat aircraft in the world and is the largest variable sweep aircraft. The program was launched in order to counter the US B-1A program with the design taking many queues from the B-1, but work continued on the Tu-160 after the B-1A program was cancelled. The design was accepted and the aircraft entered production in 1984 and produced 35 aircraft before production was ended by the new Russian Federation. In 2002 Russia received a single new commissioned Tu-160 to bolster its fleet. This was again done in 2008 for another single Tu-160. In 2015 it was announced that production of the Tu-160 would be restarted in 2019 with plans for at least 50 new Tu-160’s In 2017 another Tu-160 was completed from an incomplete airframe. The Tu-160 is the only variable geometry aircraft currently still in production. While the Tu-160 shares much of its design with the B-1A and B its purpose is different, the Tu-160’s primary mission is a cruise missile carrier standoff platform while the B-1B is primarily a bomber that is sometimes used to carry missiles, and the Tu-160 is faster and has a longer range than the B-1B but the B-1B has a larger payload.
Messerschmitt P.1101
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The Messerschmitt P.1101 was a single seat German fighter jet aircraft designed during the last years of WW2 under the emergency fighter program. A prominent feature of the design was that the sweep of the wings could be adjusted on the ground before flight to three different angles. This would allow the jet to be modified to best fit the type of mission it would have been sent out to complete. Fully swept would make the plane incredibly fast for the day and thus perfect for an interceptor. Fully deployed would allow the plane to be more maneuverable and have lower flight speeds. This would be perfect for dogfights or for Close Air Support. The prototype never saw flight and was captured and further developed by the US into the Bell X-5.
XF-10F Jaguar
The XF-10F Jaguar was the first aircraft with variable sweep that was designed with the intention of entering service with the military (US Navy). The Navy had become increasingly interested in Variable Geometry due to their concerns of continued aircraft weight increasing. Each aircraft the Navy got would be much heavier with only marginal increase in performance (sometimes with performance being the same). There were also concerns that the demand for high speed performance (requiring a more sweet wing) would make carrier operation extremely difficult to nearly impossible. The Navy saw variable geometry as a solution. The XF-10F was originally designed as a variable geometry F-9-F Panther but design changed dramatically. Wing sweep had two positions: 13.5 degrees for takeoff and landing and 42.5 degrees for high speed flight. This plane suffered from many of the same problems the X-5 had and some additional ones. At low speeds the plane was nearly uncontrollable at low speeds because of the tail design, the plane was dangerously underpowered, the sweep mechanism would often fail mid flight (Wing was designed to automatically undo the sweep if this ever happened), it had regular in flight engine problems, was dangerously unstable, and was described by its only pilot as fun to fly “because there was so much wrong with it”. With the mounting problems the project was cancelled while the navy solved its problem with steam powered catapults to launch the planes. Only one was built and it only had 32 test flights.
Su-17/20/22 Fitter
The Su-17 is a variable sweep fighter-bomber for the Soviet military in the 1960’s with the codename “Fitter”. It was the first variable sweep aircraft to enter Soviet service. The Su-17 had a long career with many air forces around the world including many eastern bloc states, middle east states, and others. The Su-17 was developed from the Su-7 swept wing fighter bomber in a bid to increase the performance of the previous design. This design saw many upgrades and newer variants throughout its life, some so extreme that they were designated a new design and given new designations. These newer designs were known as the Su-20 and Su-22, the main differences being newer technologies and payload options along with some design and visual changes.
Mig-23 Flogger
The Mig-23 is a Soviet third generation variable geometry fighter and is the most produced variable geometry aircraft in the world. It was the first soviet fighter to use look-down/shoot-down radar and was also one of the first soviet fighters to use Long range radar guided missiles (BVR or Beyond Visual Range).Over 5,000 airframes were produced from 1969-1998 in many different variants and saw service with many air forces in the world and still sees some limited service with some air forces. The Mig-23 was intended to replace the venerable Mig-21 in the air superiority and interceptor roles with the main focus of the program being increased range, radar capability, payload size, and speed with maneuverability not being much of a concern. This led to two designs, one being a modified Mig-21 with a delta wing and two lift jets and the other being a clean sheet design with variable geometry wings. The variable geometry design showed more promise and thus work on it continued until the Mig-23 was created. The design was mostly influenced by the F-4 and F-111 ( heavy, fast, high payload, and low maneuverability aircraft), however the Mig-23 retained enough maneuverability to go toe to toe with the best western designs of the time but still was lacking in that area. The Mig-23 had three angle settings: 16, 45, and 72 degrees, the pilot had to manually change the sweep. The Mig-23, despite its promise, failed to completely replace the Mig-21 in capability and was retired from many air forces before their Mig-21’s. This however does not change the fact that the mig-23 was an extremely capable and advanced plane for the day.
F-14 Tomcat
The F-14 Tomcat is an American twin engine, variable geometry, twin seat, fleet defense fighter. It was one of the first fighters designed with lessons that were being learned from air combat in Vietnam. It served from 1974 to 2006 with the US Navy and still serves today for Iran after being given to the former US friendly regime The F-14 replaced the F-4 as the Navy’s primary interceptor and air superiority fighter. The program was launched after the Navy refused to take the modified F-111B as its fighter because of how heavy it was and how limited it was in the roles the navy requires. It was the first naval fighter to field the highly advanced extremely long range Aim-54 Phoenix missile. During its design the navy opted to skip prototyping and skipped straight to full development. Unlike other variable sweep aircraft the F-14 didnt have preset angles that the pilot had to manually change, instead the F-14 had an onboard computer that controlled the angle the wing was at based on the current flight conditions. The wing could be at any angle between 20 and 68 degrees. The F-14 would go on to be one of the best fighters the navy ever fielded and remained the most famous naval fighter jet.
Su-24 Fencer
The Su-24 is a variable sweep, all-weather, supersonic attack aircraft for the Soviet Union. It has a unique cockpit configuration with both pilots next to each other and was the first soviet aircraft with an integrated digital navigation and attack system. The program originated when the Soviet Union first acquired the Su-7 and demanded that Sukhoi begin research on an all weather stick aircraft capable of precision air strikes. Originally Sukhoi wanted to avoid variable geometry but this project led nowhere. Later Sukhoi began to work on an upgrade to the Su-15 while at the same time the Soviet Air Force once again requested a new low altitude supersonic strike aircraft capable of short take off. Initially this design also didn't use variable geometry and instead used four lift jets which shortened the take off time but were a massive blow to performance. However after the introduction of the F-111 the Soviet government demanded trials of the new design with variable sweep wings, the first prototype with those wings flew in 1970 and the benefits were immediately seen. Five years later in 1975 the design was accepted into service as the Su-24. The Su-24 began production in 1967 in many variants and production ended in 1993 and has seen service with a dozen air forces and is currently still in service in Russia, Iran, Azerbaijan, Libya, Syria, Sudan, and Ukraine.
B-1B Lancer
The B-1B Lancer or “Bone” is a variable sweep supersonic heavy bomber of the USAF and is a crucial part of the USAF bomber fleet. The program started in the 1960’s and was originally supposed to replace the US bomber fleet of B-52 and B-58 bombers, with a top speed of Mach 2.2 and a payload to rival the B-52, it was given the designation of B-1A. But high costs, advent of newer cruise missiles, and the stealth bomber project all helped contribute to the program’s cancellation in 1977; but not after all of the prototypes were built and flight tests continued until 1981. The program was restarted in 1981 because of delays in other programs but the new program had different requirements and thus required a new design. The new design, labeled B-1B, differed from the B-1A in many ways. Its top speed was reduced to Mach 1.25 but the low altitude speed was increased to Mach 0.96 because the new program required higher speed at low altitudes, the computers and other tech were dramatically improved, and the aircraft could take off with maximum fuel and weapons loads now. The B-1B was first delivered in 1986 and 100 were produced by the time production ended in 1988, it entered service as a strategic nuclear bomber and later was converted for conventional bombing. 66 B-1B bombers are in service today and are predicted to be withdrawn and replaced in 2025 by the new B-21 stealth bomber.