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.

While BAe Nimrod maritime patrol aircraft were deployed to the South Atlantic in 1982 Falklands War to protect the British naval task force from Argentine surface vessels and submarines, the Nimrod also had two little-known roles during that conflict. The first role was that of "the largest fighter aircraft" when AIM-9 Sidewinder missiles were cleared for firing from underwing hardpoints with the intent of targeting the Argentinian's Boeing 707s that were being used to shadow the British naval task force. In addition, the AGM-84 Harpoon missile was cleared for use on the Nimrod in the anti-shipping role, though neither the Sidewinder or the Harpoon were fired in anger during the conflict.

The more obscure role of the Nimrod during the Falklands was that as a back up for the Avro Vulcan "Black Buck" bombing missions. The long range of the Nimrod made it a natural for the overland bombing role and a rudimentary bombsight was configured for use by the co-pilot to drop either 1000 lb air-retarded bombs or BL755 cluster bombs. A trial drop was even conducted at the Garvie Island range in Scotland.

Source: Air Forces Monthly, December 2009. "More Than A Sub-Hunter!" by Jon Lake, 32-35.

Based on the layout and delta configuration of the Avro Vulcan, the Avro Type 722 Atlantic was first proposed in June 1953. The original configuration of the Atlantic had the four engines next to the fuselage as in the Avro Vulcan, but as engineering and design work proceeded, by the time of the Farnborough Air Show in 1953 the engine pairs were moved outward halfway on the wings.

Engines were to have been in the same class as either the Olympus engines used on the Vulcan or the new Rolls-Royce Conway turbofan. The fuselage of the Atlantic was circular in cross-section with a diameter of 12.5 feet which allowed five-abreast seating for up to 120 passengers in rear-facing seats. The cabin was divided in two by a centrally-located galley which could be augmented by a bar/lounge area as well. With a length of 143 feet and a wingspan of approximately 119 feet, the Avro Atlantic would have been able to carry its passengers at a range of nearly 6,000 miles at 40,000+ feet at speeds like that of the Avro Vulcan.

Despite the publicity efforts of Avro, no interest was forthcoming in the Atlantic.
Source: Avro Vulcan: Britain's Famous Delta-Wing V-Bomber by Phil Butler and Tony Buttler. Aerofax/Midland Publishing, 2007, p55.

In October 1961 NORAD mounted its largest-ever air defense test, Exercise Skyshield. In order to be as fully realistic as possible, the Strategic Air Command's Boeing B-47 Stratojet and B-52 Stratofortress units would try to penetrate NORAD's radar and fighter defenses. In addition, No. 27 and No. 83 Squadrons of the Royal Air Force's Bomber Command each sent four Avro Vulcans to participate in Skyshield. No. 27 Squadron's four Vulcans were deployed to Kindley AFB, Bermuda, to penetrate the defense net from the south and No. 83 Squadron's four Vulcans were deployed to RAF Lossiemouth in Scotland to penetrate from the north.

On 14 October Exercise Skyshield began in earnest with the incoming bombers taking off. The northern attack began with the B-47s coming in as low as 500 feet to jam out the ground radars. Behind the Stratojets came the B-52s at 35,000 to 42,000 feet supported by jamming by EB-57 Canberras. And behind the Stratofortresses came the Vulcans at 56,000 feet. The heavy jamming was so effective that only the first Vulcan detected the radar of an F-101 Voodoo. Although NORAD scrambled many fighters, they concentrated on the B-52s and by the time the Vulcans arrived, they lacked the fuel to climb to 56,000 feet. No. 83 Squadron's Vulcans reached their target points all unscathed (which was to land at a base in Newfoundland).

The southern wave followed and used similar tactics only this time the four Vulcans from No. 27 Squadron were on their own. The four Vulcans approached the US Northeast on a broad front with their systems in full ECM and jamming. Fifty miles from the coast as defending F-102 Delta Daggers were scrambling, the southernmost Vulcan turned north and flew behind the other three Vulcans and was effectively masked by the onboard jamming of those three bombers. While the Delta Daggers swarmed the other three Vulcans, the fourth Vulcan penetrated unscathed and undetected to reach its target (which was to land at Plattsburgh AFB in upstate New York).

Source: Vulcan Units of the Cold War by Andrew Brookes, Osprey Combat Aircraft #72. Osprey Publishing, 2009, p21.