The Bristol Aeroplane Company was established in 1910 and played an important role during both World Wars for Britain. Before it went officially defunct in the 1960s, it attempted to interest the Royal Air Force (RAF) in various designs to cover a set of growing post-war requirements centered on turbojet technology. One such entry became the "Type 183" project aircraft which was developed along the lines of a variable geometry wing (also known as "swing-wing") fighter / interceptor capable of efficient subsonic and supersonic flight. The Type 183, and the related short-lived, conventional offshoot - the "Type 184" - were just some of the British-originated entries in the long and winding road that eventually culminated with the realization that was PANAVIA "Tornado" swing-wing fighter-bomber of the 1970s/1980s.
In military aviation history, there have been several notable, successful designs to utilize variable geometry wings including the Grumman F-14 "Tomcat" fleet defense fighter, the Mikoyan-Gurevich MiG-23 "Flogger" and its related MiG-27 brethren, and the Rockwell B-1 "Lancer" - and its Soviet equivalent in the Tupolev Tu-160 "Blackjack" - strategic-level bomber. The concept behind the swing-wing was in allowing a single airframe better direct control over more phases of flight, particularly as the arrival of the turbojet engine broadened the speed spectrum considerably - giving the mainplane members an inherent ability to be modified / changed as needed depending on the situation. In this way, the aircraft could maintain proper handling, lift, and drag during low-speed, low-altitude actions and become aerodynamically efficient during fast, straight-line runs. As such, during the Cold War period (1947-1991), swing-wing aircraft were popularized by both interceptor (such as the Tomcat) and strike-minded interdictor types (such as the Tornado) where speed was a necessary quality to the role.
The swing-wing concept was in play as early as the 1930s (by way of the private venture British "Pterodactyl IV") and the Germans, during World War 2 (1939-1945), were actively developing their Messerschmitt P.1101 jet-powered fighter around the approach. After the war, the incomplete airframe was passed on to American engineers of Bell Aircraft and realized in the Bell "X-5" technology demonstrator to prove many concepts sound.
For the British, there were a multitude of designs drawn up in the post-war period following this line of research as well - the Type 183 was just one of many embodiments which came to naught during the early part of the 1950s. Design-wise, this proposed aircraft was of very slim side profile with clean lines, swept-back surfaces, and a single-seat, twin-engine layout. The nosecone was well-pointed with the cockpit positioned just aft - the nose section set to house the ARI.5820 series air interception radar. The engines were aspirated by a twin-intake design with the openings straddling either side of the fuselage in the usual way - though designers added smaller intake openings aft of the primary fittings to provide ample airflow for low-speed flight, namely during the subsonic phase and these complete with self-sealing doors to close them off during the supersonic phase. The engines exhausted out of ports positioned ahead of the tail unit and the tail itself was completed in a "T-style" arrangement with the horizontal plane positioned at the absolute top of the very-swept-back single vertical tail fin. The cockpit would sport an ejection seat as part of the RAF requirement and standard / primary armament was to be 2 x 30mm ADEN automatic cannons in the lower section of the forward fuselage.
An interesting aspect of the Type 183's design was its lack of a retractable tricycle undercarriage for ground-running - namely due to the restrictive internal volume of the very slim airframe form. Instead, the aircraft would be readied on a catapult / launch rail and recovered through more unconventional means - a retractable arrestor hook was tucked under the tail for this procedure.
Still the most interesting quality of this proposed fighter / interceptor was to be its wing mainplane members which could be extended and retracted from the airflow as needed. The wings were mounted near the shoulder line of the fuselage sides and swiveled / pivoted about various hinge points and accompanying supports buried within the fuselage-center, taking up the limited space above the engine installations, airflow ductwork, and fuel stores - a considerable engineering feat in itself should it have ever come to fruition.
All told, the aircraft was drawn up with a nose-to-tail length of 65 feet and a wingspan (extended) of 46.8 feet. Gross weight was rated at 20,500lb. Power was set to come from 2 x Armstrong Siddeley "Sapphire" Sa.4 series non-afterburning turbojet engines developing 9,760lb of thrust. Estimated maximum speed was just under Mach 1.4 and its service ceiling would have reached upwards of 45,000 feet (necessitating cockpit pressurization and the aforementioned ejection seat). Bristol engineers thought that, between its naturally slim form, twin-turbojet arrangement, and retracting wing mainplanes, the Type 183 would not need reheat / afterburner to achieve the desired straight-line speeds.
The Type 184, which was submitted alongside the Type 183 by Bristol and mimicked much of the form and function of the original, was of simpler approach in that it incorporated a fixed delta-wing planform - the hope being that if the Type 183 was rejected for its complexity, the Type 184 could be accepted for its simplicity. In either case, neither form was selected and both ultimately fell to the pages of British military aviation history.