A myriad of design studies preceded what would eventually become the Eurofighter "Typhoon", a 4th Generation multirole fighter currently serving in the inventories of Britain, Germany, and Italy among others. Hawker Siddeley, longtime aircraft manufacturer for the British aviation cause, delved into a slew of design studies during the Cold War period (1947-1991) that included both conventional and some far-reaching design ideas. One entry into the realm of 4th Generation Fighter design, appearing around the mid-1970s, became the "HS.1200" which was, itself, a sub-series of studies all with the intent of creating Britain's / Europe's next fighter.
The HS.1200-6 was an offshoot of the HS.1200 product brochure and was centered on the Rolls-Royce RB.409-50R engine for power. The engine promised total thrust with reheat of 17,310lb while dry thrust running was rated around 9,710lb. The aircraft was of single-engine design with the powerplant buried within the middle-aft section of the fuselage. Similar to the General Dynamics F-16 "Fighting Falcon" of the same period, the British aircraft could feature a single ventral air intake aspirating the engine within and a single exhaust port at the rear of the fuselage. The cockpit was seated out and over the intake behind a well-pointed nosecone housing radar. The canopy, like the F-16, would have a reclined seating position and excellent vision out-of-the-cockpit for its single crewman.
The wing mainplanes were drawn up with near-straight trailing edges and swept-back leading edges (just as in the F-16) with wingtips sporting missile launchers. Furthermore, the members were blended to the body for extreme streamlining of the design to promote better form at the high speeds expected of this fighter. Unlike the F-16, however, was the intended use of twin vertical tail fins, these straddling the engine at the rear. The horizontal planes, bookending the engine exhaust nozzle, were set well-aft in the design. Ventral strakes were added to the aft-section of the fuselage for additional control. A retractable, wheeled tricycle undercarriage rounded out the physical characteristics of this aircraft.
Internally, the aircraft would have a standard armament arrangement involving 2 x 30mm ADEN automatic cannons providing an inherent - and hefty - frontal punch against enemy aircraft (including bombers). Beyond this armament, the aircraft was to carry short-ranged Air-to-Air Missiles (AAMs) at the wingtip mounts and six total (three per wing member) underwing hardpoints for additional AAMs or air-to-ground air-launched / air-dropped ordnance.
Performance specifications (estimated) included a maximum speed of between Mach 1.2 and Mach 1.3. The aircraft's service ceiling was to reach close to 40,000 feet.
Finalized dimensions of the HS.1200-6 were an overall length of 44 feet with a wingspan measuring 32.5 feet. Weight was to reach 22,000lb when fully equipped for Air-to-Air (A2A) combat (2 x AIM-9 "Sidewinder" AAMs with internal cannons and fuel load).
Design study HS.1200-7 was to switch power to the RB.246-06 engine for improved performance. A redesign of the intake opening as well as enlarged surfaces of the aircraft on the whole were also planned for this entry - resulting in a top speed estimate of about Mach 1.45.
In any case, the HS.1200 was not advanced into any viable form despite being promoted and submitted by the company. The subsequent HS.1201 was a completely different proposed fighter form and is detailed elsewhere on this site.