BEA Gets the Trident and More

BEA Trident 1C in the original delivery colors
(Wikipedia)

A while back I had posted about a short lived proposal between Boeing and De Havilland for the former company to license build the DH.121 Trident in the United States. That was but one of many twists and turns in the rivalry between the DH.121 Trident and the Boeing 727. Building on the success of the 707 family, Boeing next launched the 727-100 for the short-haul market and like the Trident, was a T-tailed three-engined aircraft built broadly to the same specifications. But having cut its teeth on the commercial market successfully with the 707, the 727 quickly gained fame as a technological and aerodynamic success that could fly near its limiting Mach number at 37,000 feet smoothly yet possess the high-lift wings to allow it to land at speeds as low as 100mph and serve short airfields and smaller communities. The Trident, on the other hand, wasn't designed for short field performance and had the nickname "Gripper" by its pilots on account of its long takeoff run. Its engines weren't as powerful as the new Pratt & Whitney JT8Ds on the 727 and De Havilland actually pitched the Trident as an "economy aircraft" on contrast with the hot rod performance of the 727. 

De Havilland originally had designed a larger aircraft that could have boasted the seat-mile economics of the 727, but as the aircraft was being designed to British European Airways (BEA) requirements for European services, BEA wanted a smaller aircraft and the first version of the Trident carried only 78 passengers. It ended up having to compete with the successful Caravelle in capacity below the Trident and the Boeing 727 on the top end of the capacity segment. De Havilland even tried to pitch a version of the Trident to American Airlines which at that point hadn't made up its mind yet on the 727 whereas Eastern and United had already committed their launch orders. But in August 1961 American followed United and Eastern in ordering 25 727-100s in a crushing blow to the British sales effort. And to add insult to injury, De Havilland was having a difficult time pleasing BEA, its planned primary customer as BEA kept changing its requirements and asking for changes to the Trident design. Once changed and approved for production, BEA would come back with another set of changes resulting in a small production block with several different variants to suit BEA's wishes. Some in the De Havilland program felt that BEA was trying to sabotage the Trident with its requests while Boeing turned out 727s in only two basic versions by the hundreds. Even later versions of the Trident with higher-powered Rolls-Royce Spey engines and longer fuselages to carry more passengers failed to dent the 727 worldwide sales juggernaut as order after order bypassed the Trident in favor of the 727.

BEA Trident Two- the aircraft was progressively improved
(Wikipedia)

On 22 November 1965 the British Minister of Aviation, John Stonehouse, affirmed the government's support for the longer ranged Trident Two version which interested BEA more than the Trident 1 versions (despite the Trident 1 being built to BEA's own specifications). Parliament even approved funding to launch the Trident Two program. But in the following year, the head of BEA, Sir Anthony Milward, not only said BEA needed less capacity than the Trident Two, but that he had also had discussions with Boeing and Douglas. Some historians feel that Milward was engaged in brinkmanship with the UK government to get the Tridents as the lowest price possible. Milward himself stated publicly that "BEA wanted to buy British, but that it could not afford to buy British if the product was not the best on the market." De Havilland then went on to create the Trident Three, BAC offered a stretched version of the BAC One-Eleven and even Vickers proposed a short-haul version of the VC-10. But the 727-200, 737-200, and the DC-9 were also on BEA's table for discussion. 

With the election of a new Labour Party government keen on supporting British industry, Milward warned that "If a British aircraft was available to do this job at the right price we'd be delighted. At the moment there are no signs that such a British aircraft is available." It was well-known that BEA had asked for approval to purchase 35 727-200s and 737-200s. De Havilland was astonished that after creating larger versions of the Trident, BEA said the market had an overcapacity, but then turned around and wanted order larger American aircraft. 

BEA Trident Three in British European's final livery
(Wikipedia)

Already the Labour government was under fire for campaigning to support British industry but had already ordered the McDonnell Douglas F-4 Phantom, the Lockheed C-130 Hercules, and the General Dynamics F-111 to replace the canceled TSR.2. Despite BEA's desires for American jets, the political winds in London of the day dictated that they had to buy British, no matter what. BAC offered the Two-Eleven successor design to the One-Eleven, but BAC required millions of dollars in launch aid to start work on the Two-Eleven. Eventually the Two-Eleven project had to be abandoned and support had to be shifted over to the penultimate version of the Trident, the Trident Three. BEA was directed to purchase this aircraft and Milward made plain that the Trident Three was BEA's third choice and if it were compelled to operate the Trident Three, then BEA should receive compensation from the British government for not getting the more economical 727-200s and 737-200s they wanted. 

The new Minister of Aviation, John Mulley, found himself backed into a corner by BEA and the British government. BEA had to buy the Trident Three at the direction of the government but BEA wanted compensation to offset the higher operating economics of operating the Trident Three. 

On 13 March 1968, BEA announced it was ordering 26 Trident Threes with options for 10 more. Four months later, the government announced what was called the "Mulley Pledge"- approximately US$50 million was transferred to BEA and was calculated to be the cost difference between the higher seat-mile costs of the Trident Three versus the 727-200. And additional 50% of that initial transfer would be made available later to BEA, fufilling the Labour government's pledge to support the British aircraft industry. 

Source: Flight of the Titans: Boeing, Airbus, and the Battle for the Future of Air Travel by Kenny Kemp. Virgin Books, 2006, p65-74.

Although progressively improved and more powerful versions of the Bristol Olympus jet engine powered the Avro Vulcan bomber, there were also other versions of the Olympus destined for other aircraft that made their initial flights on specially-converted Vulcan testbed aircraft. In addition, other similarly-equipped Vulcans served to flight test other engines during their development cycles as well.

The first engine to be flight tested on the Vulcan wasn't an Olympus variant, though. That honor goes to the Rolls-Royce Conway low-bypass turbofan. The first prototype Vulcan, tail number VX770, was retrofitted with four Conway engines in 1956 and delivered to Rolls-Royce for the start of the Conway flight test program in August 1957. Unfortunately, VX770 was lost during a Battle of Britain flying display at RAF Syterston in September 1958 when the maneuvers it was performing overstressed the airframe, resulting in the loss of the crew. A second Vulcan bomber, XA902, was then selected to undergo conversion with the Conway engines to replace VX770. The conversion work began at Avro's facilities in December 1958 and was completed in July 1959. The Conway engines used were the Conway 11 engines (RAF designation Conway Mk.102 and 103) which were destined for use on the Handley Page Victor B.2, an upgraded version of the original Victor B.1 model.

The Conway test program called for the engines to be run at cruise power at 40,000 feet- however, at that power setting, the Conway 11s were more powerful than the Olympus engines of the Vulcan and the testbed would have easily exceeded the Vulcan's maximum speed and overstressed the airframe! As a result, the Conway 11 engines had to be operated at lower thrust settings similar to what was used on BOAC's Boeing 707-430 jetliners. It was found that two Conways could be operated at cruise settings as long as the other two engines were run at lower settings. Given that the prototype Vulcan VX770 that was lost wasn't as structurally strong as XA902, it became possible to complete the Conway flight test program.

With the Conway test program complete in 1961, XA902 was then converted to take Rolls-Royce Spey engines on the inboard positions while retaining the Conway 11 engines on the outboard positions. It made its first flight in this configuration in October 1961 to support the Spey development for its use on De Havilland DH.121 Trident, the BAC One-Eleven, the Blackburn Buccaneer S.2 and the Hawker Siddley Nimrod. XA902 would be retired from service in 1963.

In 1962, another early-mark Vulcan B.1 was taken from service to test the Olympus 22R engine that was destined for the BAC TSR.2. Vulcan XA894 was modified with a large ventral nacelle with bifurcated intake on each side of the nose landing gear. Conversion work on XA894 began at Filton in 1960 and it made its first flight with the much more powerful Olympus 22R in February 1962 in support of the TSR.2 development program. In December of that year during a ground run test, an uncontained turbine blade failure resulted in a fire that destroyed XA894. No replacement was needed, though, as the Olympus 22R had completed enough of the needed test points for the TSR.2 program.

In 1964, another Vulcan was pulled from service to serve as an engine testbed, this time it was tail number XA903 which arrived at Filton in January of that year for conversion work to flight test the Olympus 593 in support of the development of the BAC/Aerospatiale Concorde. Using a similar ventral nacelle as had been used on XA894 in the Olympus 22R flight test program, this time instead of a bifurcated intake a straight-through intake was used that resembled a single-engine Concorde engine nacelle. A retractable spray bar was also fitted ahead of the intake and water from a bomb bay water tank was used to test water ingestion and icing conditions on the Olympus 593 engine. The first flight was made with the Concorde engine in September 1966 and the test program finally ended in 1971 with over 400 hours of flight time. With the Olympus 593 at full power, the Vulcan testbed could still fly and maneuver with its own four engines at idle!

Testbed work would continue for XA903, though. In August of 1971 XA903 was flown to Marshalls of Cambridge for conversion work to support the development of the Rolls-Royce/Turbo Union RB.199 engine for the Panavia Tornado program. The ventral nacelle used for the Olympus 593 program was modified by Marshalls to not only accommodate the RB.199 engine, but to replicate the starboard side of the Tornado's fuselage. The first flight with the RB.199 was made in April 1973 and one of the most unusual aspects of the RB.199 flight test program was that the ventral nacelle was even equipped with a Mauser 27mm cannon that would be used on the Tornado. The cannon's location in relation to the intake replicated its location on the Tornado so that gun gas ingestion trials could be carried out. The firing trials were carried out at Boscombe Down but weren't done while airborne- XA903 remained on the ground and firing butts were used while Rolls-Royce and Turbo Union engineers analyzed the engine's performance as gun gas was drawn into the intake. A total of 285 flight hours were accumulated with the RB.199 on XA903 when the Vulcan was finally retired in February 1979, the last early-mark Vulcan B.1 to have flown.

Source: Avro Vulcan- Britain's Famous Delta-Wing V-Bomber by Phil Butler and Tony Buttler. Midland Publishing/Aerofax, 2007, p70-73.

One year before Boeing announced the go-ahead of the Boeing 727 program on 5 December 1960, there were serious reservations within the manufacturer about whether or not to proceed with the 727. At the time Boeing's commercial division was still quite a bit smaller than the military aircraft division and the company's desire to have wide customer base resulted in numerous variations in the Boeing 707/720 family that stretched the company's resources to the point that for every 707 delivered, Boeing was taking a $1 million loss. At this point, the De Havilland in Britain was about a year ahead of Boeing on work on its own trijet, the DH.121 Trident which was designed to broadly meet a similar set of specifications as that of the 727.

De Havilland saved itself a lot of time as it was specified from the start to have three engines while Boeing's design studies alternated between four and two-engined designs before settling on three engines. Before a T-tail design was settled upon for the 727, a group of Boeing engineers visited De Havilland's Hatfield factory to review the progress on the Trident and the visit was reciprocated shortly afterwards when a group of engineers from De Havilland visited Boeing's Seattle facilities to review the progress on the 727. At this point, the British firm suggested an Anglo-American alliance with Boeing building the Trident under license and worldwide sales markets divided between the American Trident team and the British Trident team. De Havilland would have a bigger customer base and lower unit price for its Trident design and Boeing wouldn't have to commit what was estimated to be $100 million to get the 727 program to completion of the prototypes and first flight.

As surprising as it may sound today, Boeing was very unsure of itself in the commercial market and the De Havilland proposal offered a low-risk way of getting into the short-haul market and there was a considerable amount of convergence in the two designs. However, Boeing wanted the capability to operate from a 5,000 foot runway, a specification that didn't factor into the Trident design (as a matter of fact, the Trident's early versions had a reputation amongst pilots as "ground grippers"). The two teams then looked at the possibility of putting the 727's high lift wing on the Trident, but the costs of the engineering required were identical to that of proceeding with the 727 program. The proposal for the alliance quietly died and to many at De Havilland came as no surprise.

When the 727 was rolled out, there were accusations in the British press that it was copied from the Trident, but De Havilland's engineers were adamant in interviews in dismissing the furor and reminded a skeptical public that Boeing did have first-class wind tunnel facilities and some of the finest aerodynamicists and engineers in the world would would have arrived naturally at some of the conclusions that resulted in the layout of both aircraft!

Source: Boeing 727 (Modern Civil Aircraft:13) by Peter Gilchrist. Ian Allan Press, 1996, p7-16.