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Business Aviation Industry Focus: DeHavilland 125

by Jeremy Cox 1. September 2008 00:00
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In 1958 the most successful designer and manufacturer of general aviation aircraft in Great Britain, Sir Geoffrey De Havilland - OBE/CBE (he was knighted in 1944 in reward for his services to the country) was struggling to bring his company back to profitability again after the tragic window design issues on his and the world's first jet airliner, the a DH 106 Comet had been fixed. The Mark IV Comet had just been returned to airline service (unfortunately too late) and even though he had officially retired in 1955 he continued to serve as the head of the company and he subsequently decided that it was time for his company to design a small business jet aircraft. His vision was of an aircraft that was sized between his extremely popular 1930's twin-engined-piston Gypsy Six powered DH 89 Dragon Rapide (also known as the Dominie within military service) and it's successor, the postwar twin-engined-piston Gypsy Queen powered DH 104 Dove. The Rapide seats eight passengers, four on either side of an aisle in a 'nearly' stand-up cabin, while the Dove seats eleven in a proper stand-up cabin. Sir Geoffrey, who was in his mid seventies by now, and his team, took the conceptual size of both the Rapides and Doves cabins and created the Jet Dragon, designated as the DH 125. The British post-war economy was booming in 1960; however the corporate treasury of DeHavilland had been depleted near to bankruptcy due to the Comet window design tragedies. Sir Geoffrey was grateful to be able to pass ownership of his company over to Hawker Siddeley Aviation. The DeHavilland name was kept until 1963.

The prototype DH125 Mark 1 first flew on August 13th, 1962 from Hatfield Aerodrome in Hertfordshire, about twenty miles north of central London. It was powered by two Armstrong Siddeley (later to be Bristol Siddeley, then Rolls Royce) Viper engines. These fine engines were a smaller derivative based upon the successful Armstrong Siddeley Sapphire turbojet that powered the Gloster Javelin and the Hawker Hunter of 1951. Eight Mark 1's were produced before the subsequent aircraft were fitted with up-rated Viper engines and designated Mark 1A (Viper 521) or Mark 1B (Viper 522.)

Shortly after the first flight of the DH 125 in 1962, Time Magazine wrote an article the same year that describes the DeHavilland aircraft as follows: "_the DH 125 was designed to operate on short runways and cruise with six passengers at 480 m.p.h., it is Britain's entry in the market for corporate jets. Price: $550,000_"

It is easy to confuse the 'A' and 'B' designations when they applied to the DH 125 and subsequent variants. The United Kingdom's Civil Aviation Authority (CAA) and our FAA, up until 1999, designated all of the aircraft that were approved and destined for the North American market as 'A' models (America); with the rest of the world designated as 'B' models (British.) The DH 125 Mark 1A was Type Certificate Approved by the FAA in the United States on September 23rd, 1964. The Mark 1A featured an unrestricted take-off and continuous engine thrust of 3,120 lbs that allowed 21,200 lbs MGTOW and accommodations for 8 passengers and 2 crew. The maximum rated altitude was 40,000 feet. The Mark 1B powered by the Viper 522 benefited by an additional 210 lbs of thrust for a 5 minute maximum continuous thrust of 3,330 lbs. Mmo (Maximum Mach Operating Speed) was also increased at altitude from 0.735 mach, to 0.75 mach. Nine months before the Mark 1B was approved by the FAA, Sir Geoffrey passed away after suffering a cerebral haermorrage at age 82.

The labour government of the then prime minister: James Callaghan, finished the work that had been started by his Labour colleague and former prime minister, Harold Wilson in the 1960's. Wilson had engineered the unification (and eventually nationalization) of the aviation industry. In April 1977 the forced merger of Hawker Siddeley with British Aircraft Corporation and Scottish Aviation was executed to create the government owned entity named British Aerospace (BAe.) If Sir Geoffrey had still been alive, he most likely would have fought this governmental merger plan with 'hair, blood, tooth and nail.'

The month following the forced nationalization of Hawker Siddeley into BAe, the engineers and executives celebrated the certification of their first Turbo-Fan powered version of the Jet Dragon; the HS125-700 Model fitted with two Garrett AiResearch TFE 731-3 engines. Prior to the introduction of the Model 700, the worldwide DH/HS 125 fleet amounted to over two hundred and fifty various Viper Turbo-Jet (now Rolls Royce) powered models, which included the Mark 1A; Mark B; Mark 2; Mark 3; Model 400 and Model 600 all for the civilian world, and the new Dominie model that was manufactured exclusively for the Military.

As a side note, the DH/HS 125 Dominie got its name from the military version of the DH 89 Rapide previously mentioned in this article. The Royal Air Force of Great Britain is the Dominie's primary customer, but it was, and in most cases, still is used by a multitude of military forces around the world. The Rolls Royce Viper 301 powered Dominie T1 has been in continuous service with the Royal Air Force (RAF) since 1965. According to the RAF, the Dominie today is used to train weapon systems officers and operators, air engineers and air loadmasters. With up to five students on board in the back, plus two crew up-front, a mixture of two-to-three hour sorties are flown, including both low and high-level flying, maritime operations, radar handling and target training.

Both the HS 125-600 and the HS/BAe 125-700 has the same fuel capacity of 1,419 U.S. Gallons, but the replacement of the Vipers with the Garrett Fans virtually doubled the range of the latter version; from approximately 1,100 NM to an impressive 2,100 NM. Static thrust of both the Viper and the Garrett were almost identical, with the Fan delivering 25 lbs additional thrust over the Turbo-Jet, in a 'stage-three' noise compliant package. Over the following decade, 100 various Viper powered aircraft were retrofitted with the Garrett Fan under after-market Supplemental Type Certificates (STCs) developed by AiResearch.

After Hawker Siddeley (HS) had completed its purchase of the De Havilland Aircraft Company, and also after the eight original DH 125 prototypes had been completed at the DH facility in Hatfield, HS moved all production of the 125 series 195 miles northwest to the DH facility that used to build the famous twine-engine DH 98 Mosquito attack/bomber, in the city of Chester, in Cheshire close to the border of Wales. It is here that production has remained ever since. It has even withstood the purchase of BAe's Business Jet Division by the North American behemoth, the Raytheon Company in 1993. Raytheon Aircraft Company (Beechcraft) moved completion and delivery of the BAe 125, which was now being produced as the model 800. Raytheon renamed the aircraft simply as 'Hawker.' After much upheaval of personnel Raytheon created an enclave of English men and women within the metropolitan areas of both Wichita and Little-Rock (BAe had built a delivery and sales centre for its U.S.A. Jetstream, 146 and ATP transport aircraft division in Little Rock, Arkansas prior to the Raytheon purchase; now a service and completion centre for the Hawker.) In 1996 some sub assembly manufacturing and all final assembly operations were moved to Wichita. Eight years prior to the purchase of the Hawker program in 1993, Raytheon Aircraft, nee Beechcraft, had started their jet aircraft product division in 1985 after purchasing the Diamond aircraft program from Mitsubishi in Japan and then renaming it the Beechjet. It seemed now that Raytheon were the new rulers of business and general aviation manufacture, as their product line encompassed the entire gamut of general aviation starting with their single-engine piston powered Beechcraft Bonanza, to the twin-engine piston powered Baron, the twin-engined PT6A turbo-prop powered King Air series of aircraft, the futuristic Starship, the Beechjet, the all-plastic Premier and the Hawker series. Additionally other divisions were building the Beech 1800/1900 airliners, and the license built Swiss military trainer from Pilatus that is called the Mark 2 T-6 Texan.

After growing this aircraft manufacturing company into what it is today, Raytheon sold it off to an investment consortium in 2007, which promptly renamed the entire operation 'Hawker Beechcraft' by combining two very illustrious and historic names.

Geoffrey DeHavilland's Jet Dragon has gradually evolved over the last 46 years starting from the Mark 1A, through the various models previously mentioned above, on to the model 1000, model 800XP, and now in its latest 2008 manifestation: the model 850XP, 900XP and the soon to fly, the model 750. Today a total of 1,657 Jet Dragon derivatives have been built and delivered around the world, since 1962; 1,457 of which are still operating. Everyone I believe can only take their hat off and doff it in respect to this impressive production history. Do you agree?

Okay so next month we shall focus on the Jet Commander as we further continue this look-back at the history of the various aircraft that have shaped modern business aviation. If you have a suggestion for me as to a specific business aircraft that one of these future Business Aviation focus articles should be dedicated to, please let me know your thoughts. Also remember that any input that you care to make will be of great interest to all of the readers here at Globalair.com. So don't be bashful. Go ahead and write your comments and suggestions here. Please don't forget that whatever you write here, can be seen publicly by everyone that visits this page, so please be funny, be inspired, but most importantly of all, please be nice.

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Jeremy Cox


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