de Havilland DH 125
In the late 1950's de Havilland Aircraft Co. were considering the replacement for its highly respected Dove aircraft. At the time there was widespread use of jet aircraft by airlines throughout the world and de Havilland desired an executive aircraft to complete with this. A list of 'must have' features was drawn up. Cruseing speed would have to be at least around the 500mph range. Be able to carry 8 people and their luggage, non-stop between any two capitals or major industrial areas within Western Europe. The need to be able to be accommodated by any airfield currently able to accept executive aircraft meant that performance and ground handling would be such that even small airfields wouldn't find the aircraft a problem.
In April 1961 de Havilland, who became part of Hawker Siddeley Aviation in 1960, announced to the world that they were intending to build a new pure jet aircraft called the de Havilland DH125 Jet Dragon.
In July 1962 the first prototype was rolled out. Registered G-ARYA with a construction number of 25001. Its maiden flight was on 13th August 1962 and too 56 minutes. On 12th December 1962 the maiden flight of the second prototype too place. Registered G-ARYB (c/n 25002). Both prototypes were assembled at Hatfield and had Viper 511 engines which gave 2,500lbs static thrust. Length was 46ft 5ins with an initial wingspan of 44ft but during development 18 inches was added to each wing tip increasing overall span to 47ft. This increased the performance of the aircraft and became the standard wing span width for all 125's until the redesign for the series 800 aircraft.
Production of the 125 was to be at Hawarden, near Chester and production aircraft were 12 longer than the prototypes. This was most noticeable by the cabin door now being wider at 36 inches. The first production aircraft, G-ARYC (c/n 25003) undertook flight testing for the Viper 520 engine. These engines produced 3,000lbs static thrust. The two prototypes were later re-fitted with these engines.
Second production aircraft, G-ASEC (c/n 25004) was the first to have wing fences in the middle of each wing. This was to become standard on all 125's
A total of 8 Series 1 production aircraft were produced (c/n 25002 to 25010).
In 1963 the RAF ordered twenty DH125's for navigational training. These aircraft were 1B aircraft, however they had Viper 301 engines producing 3,000lb static trust, six windows on the port side but only 4 on the starboard. A ventral fin was added underneath the rear fuselage. These aircraft were designated by de Havilland as Series 2 aircraft but the RAF called them Dominie T Mk 1's. Construction number 25011 was the first of these aircraft and was given the serial XS709. It first flew on 30 December 1964 and entered RAF service on 30th March 1965. This aircraft is now preserved at the RAF Museum, Cosford. Further details of these aircraft can be found in the Series 2 page.
During this time, the series 1A/1B was introduced, whose main visual difference was the reduction of cabin windows from six to five. An upgraded engine, the Viper 521, was introduced giving 3,120lbs static thrust
The 1A was marketed in the US and Canada as apposed to the 1B which was marketed for the rest of the world. The 1A gained FAA flight certificate A3EU on 25th September 1964. 1A aircraft, with temporary avionics, were flown to one of three distributors for fitting out to customer requirements. The three distributors were Atlantic Aviation at Wilmington (for East coast customers), AiResearch at Los Angeles (for West coast customers) and Canadian customers were handled by Trimmins Aviation in Montreal.
The 1B aircraft were fitted out at Chester with Hawker Siddeley air conditioning and avionics.
de Havilland was amalgamated fully into Hawker Siddeley and became the HS125. However the name de Havilland and the designation DH125 was still used in the US as this was better known.
In 1966 the Viper 522 engine was introduced with 3,310lbs static thrust. Aircraft fitted with the new engine from construction were designated 1A/522 or 1B/522 with those aircraft retrofitted with the engines becoming 1A/S522 or 1B/S522's (c/n 25090 and 25109).
A total of 80 Series 1A/1B aircraft were completed. These together with the Series 2 aircraft for the RAF took the construction numbers up to 25110.