It was an aircraft that led a double life. As first the world air speed recordbreaking Fairey Delta 2, and then the BAC 221 testbed, one remarkable airframe made many contributions to the advancement of British aviation. This is the diary of its time as the 221, proving the concept of Concorde’s wing design
As the concept of a supersonic airliner neared reality, so Bristol’s Type 223 design was retained for development. It would, of course, evolve as the Anglo-French Concorde. Th e Type 223 incorporated a slender delta ogee wing offering a favourable combination of lift, drag and stability, a configuration that needed flight-testing. An aeroplane that had already made its mark by breaking the absolute world speed record was to become the platform.
Th e first of two Fairey Delta 2 (FD2) supersonic research aircraft, WG774, was chosen for conversion into a high-speed demonstrator of the Type 223’s planform. Designated as the Bristol Type 221, it was intended to explore the behaviour of a slender wing at various angles of attack. Th e platform to evaluate the slender wing in low-speed flight, the Handley Page HP115, was launched at the same time.
WG774 was flown to Filton on 5 September 1960 by Bristol chief test pilot Godfrey Auty, who was named project pilot for the new aircraft. Conversion began on 30 May 1961, the Type 221 being named the BAC 221 after Bristol was merged into the British Aircraft Corporation. It retained the FD2’s drooping nose, which could be lowered hydraulically by 10°, but intermediate angles of 5° and 8° were added. Th e Rolls-Royce Avon RA28 engine with reheat was also kept. Th e largest task was designing and building the new wing and integrating it with the airframe.
The completed BAC 221 was rolled out at Filton on 7 July 1963, still fitted with the cramped FD2 cockpit. Auty carried out functional checks and found the addition of extra equipment further restricted the amount of elbow room available.
The FD2 was very demanding to fly. As the BAC 221 it acquired more extreme characteristics. A piloted, 31-hour simulation of its handling in the approach configuration was made by the Royal Aircraft Establishment in late 1963, representing the aeroplane with its undercarriage locked down and the nose fully drooped. It was feared that the confined cockpit might interfere with control of the aircraft, especially for larger pilots, so the simulator seat back was padded. The rudder pedals were fixed so close to the pilot that his knees were forced up around the control stick.
The FD2 was also simulated for comparison. Pilots concluded that there should be few problems flying the 221, as they referred to the machine. They said its handling characteristics were acceptable for a research aircraft.
There were no test rigs for the 221 programme. All modifications were made to flying standard and tested on the aircraft, which delayed the first flight. In preparation, Auty simulated engine failure in the descent and approach phases using a Hunter. By April 1964, preparations for the maiden flight were complete, and Auty conducted an initial taxi trial at Filton on 24 April. This is the diary of what followed.
Flight 1: 1 May 1964 Godfrey Auty made the 221’s maiden flight. Only the nose section and the tail were painted and the undercarriage doors had been removed. The 23-minute sortie was supersonic and was chased by BAC’s ‘Willy’ Williamson in a Hunter and RAE test pilot Clive Rustin in a Meteor. Auty found the 221’s low-speed handling nicer than the FD2’s.
Flight 2: 13 May 1964 This flight followed two take-off aborts due to nosewheel shimmy.
Flight 3: 20 May 1964 Reheat was used successfully for the first time, and this flight was made with all undercarriage doors fitted. It completed Stage I clearance flying, during which the auto-stabiliser and auto-throttle were not operated.
Auty wrote, “The modification of the Fairey Delta 2 to the Type 221 has produced a new aircraft of unique shape and research capability, which, within the limited envelope tested, has displayed flying and handling characteristics superior to its predecessor.
“In view of the importance of this aircraft, not only as a pure research aircraft, but as a means of establishing handling and performance criteria for the Concorde project; it is regrettable that only advances in the aerodynamic art have been embodied in the aircraft, and that equal priority was not given to systems integrity, pilot environment and operational features to produce an aircraft compatible with present day operational conditions and flight safety standards, thus enabling the pilot to make better use of the limited flight time for research purposes.
Flight 4: 30 July 1964 The first part of Stage II clearance flying began.
Flight 5: 25 August 1964 Dutch rolls and low-speed handling tests with the undercarriage and nose lowered were made on the descent.
Flight 6: 25 August 1964 Williamson’s first flight on type, chased by Auty in Hunter F6 XF509.
Flight 7: 26 August 1964 Rustin became the first military pilot to fly the 221. He found it much easier to fly than the FD2 but required faster control response. Reheat was used for the climb from 20,000 to 30,000ft.
Flight 8: 26 August 1964 With Williamson at the controls, six ‘bonker’ firings were made for flutter tests at 30,000ft. These devices were miniature rockets with a brief burning time, and were mounted at the top of the fin and above and below each wingtip.
Flights 9 and 10: 28 August 1964 Assessments of engine performance, but a starter failure and the complete disintegration of a terminal box caused another small fire in the 221 during a ground run.
Flight 11: 31 August 1964 This flight was supersonic and included a climb test.
Flight 12: 4 September 1964 An air test. Pilots reported that the handling characteristics of the actual aircraft and the simulated 221 were similar.
Flights 13-19: 5-13 September Th e 221 was ferried to Farnborough for the SBAC show. Th ere, Auty and Williamson made six display flights in a routine which included a take-off with reheat, accelerating and decelerating turns of one-mile radius, high-speed and low passes, circuits, approach and landing. After the last demonstration, it was discovered that a significant fire had broken out in the 221’s rear fuselage. Repairs were carried out at Farnborough and were competed on 9 October.
Flight 20: 3 November 1964 Concluded the first part of Stage II clearance flying and returned the 221 from Farnborough to Filton, where it was laid-up for several weeks for a resonance programme. Lateral oscillations had been consistently reported by the pilots during flights 4-20.
Flight 21: 1 January 1965 Th e start of a series of flights for the extension of the 221’s envelope, in particular flutter and auto-stabiliser clearance. Some sorties were made with a drogue parachute attached on each wingtip and with ballast. Flights 21-28 also allowed BAC to complete drag calculations.
Flight 23: 6 January 1965 With Auty flying, the engine did not respond to throttle input when more power was demanded following selection of undercarriage down on the landing approach. Full thrust was not achieved until the 221 was 200ft above the airfield, three miles from the runway threshold. Th e aircraft made its approach at 200kt with the nose un-drooped and touched down at 170kt. Th e brake parachute was deployed on landing. Rolls-Royce and Bristol Siddeley Engines investigated the incident, confirming that engine accelerations from such a low speed as 3,300rpm may occasionally be extremely slow if the engine was in a partially stalled state, and this was thought to be the case. A flight idle detent was fitted to the throttle box.
In the first part of 1965, a major modification programme was implemented on the 221. Th e metal canopy from the FD2 was replaced by a frangible Plexiglas canopy, safer in case of pilot ejection; the cockpit interior was altered and the tail fin extended by 8in.
Flight 29: 23 August 1965 Th e second part of Stage II clearance flying began. Th e main objective was to validate the new configuration, particularly the frangible canopy. Flights 29 and 30 were intended for flame-out practice, but due to the malfunction of the undercarriage door lock on flight 29 and loss of cabin pressure on flight 30, this was postponed. Pilots rehearsed the flame-out procedures using Aero Flight’s Hunter F6 in a configuration representative of the 221.
Flight 35: 7 September 1965 Th e 221 was ferried from Filton to Bedford, to participate in Exercise ‘Unison 65’ at the RAF College Cranwell. A display practice was made at Bedford before landing. Th e advantage of the new canopy was appreciated in the accelerating turn where visibility had been limited with the old design.
Flight 36: 8 September 1965 Another rehearsal for the event at Cranwell, which also included a flame-out practice. However, the 221’s flying display at the RAF College was cancelled due to the weather. Low-speed clearance tests were made on the return flight to Filton, which took in a low-speed display for the British and French aviation ministers.
Flight 40: 15 October 1965 Auty reported engine rumble and thrust surging. He made drag measurement flights that month.
Flight 43: 20 October 1965 Planned as a supersonic stability test, but due to the poor visibility a subsonic flight was substituted to ensure adequate fuel reserves for the approach and landing. The 221 climbed to 11,000ft, then decelerated and descended to 5,000ft. The undercarriage was lowered and the airbrakes retracted at 180kt. The nose drooped and the auto-throttle selector was set up, but the engine was not responding to the throttle lever inputs. Then, as speed increased with lost height, the engine responded and the aircraft was accelerated without further height loss. Very pronounced thrust surge was noticed.
Flight 44: 24 February 1966 The weather having previously precluded any flying in 1966 — though RAE pilot Dickie Millward performed a ground run at Filton on 14 January — at Filton the 221 now started a number of drag measurement flights.
Flights 46-60: March 1966 This series of sorties included flights 51 and 52 on 8 March, which were made by RAE pilots Rustin and Millward in preparation for delivery of the 221 to Bedford. Flight 52 was Millward’s first in the 221 and was subsonic. It ended with a conventional radar descent. Millward wrote that the 221 was more pleasant to fly than the FD2. He stressed the tremendous improvement in all-round visibility through the Plexiglas canopy, which gave an immediate impression of relative comfort and safety and added to the pleasure of flying the 221, in contrast with what he called the claustrophobic, “sardine” atmosphere of the FD2. He wrote that little difference was detected in the directional damping characteristics with and without the auto-stabiliser engaged but complained about the complicated layout of the instrumentation switches, which greatly increased pilot workload.
By then, the BAC contractor demonstration programme had been completed by expanding the 221’s flight envelope to its limit and clearing it for flight down to 135kt. During the last 12 contractor flights, the wings were tufted and a 16mm camera was mounted in a bullet fairing at the top of the fin to photograph the tufting at low speeds, the blue colour of the whole aircraft providing a good background.
Flight 61: 20 May 1966 The 221 arrived at Bedford for an RAE research programme to validate the planform of the Concorde. The 35-minute delivery flight was made by Rustin, the 221’s RAE project pilot. Objectives of the initial flights there were listed by Aero Flight HighSpeed Section leader Bob Rose. They included familiarisation, measurement of altitude pressure errors in formation with the calibrated Javelin, and low-speed flight investigations.
Flight 62: 2 June 1966 Rustin became the first pilot to take off from Bedford in the 221.
Flight 68: 13 June 1966 The 221 was flown alongside the second FD2, WG777, to check the oscillations induced by one supersonic aircraft on another. Comparisons were made between the two aircraft for various 221 configurations. According to pilots, landing the 221 with the nose un-drooped was easier than in the FD2. Incidentally, WG777 was last flown on 13 July 1966.
Flight 69: 13 June 1966 RAE test pilot Tony Hawkes made his first 221 trip. That month, the 221 logged 12 flights, mainly for the familiarisation of Rustin, Millward and Hawkes who were chased by Auty in Hunter F6 WW598. The Hunter flew in formation with the 221 at 10,000ft.
Flight 76: 7 July 1966 Rustin made a start on PEC (pressure error correction) work. In PEC flights at low altitudes, the aircraft was fitted with a sensitive aneroid and flown at a range of speeds past a camera on the control tower. This method required calm conditions, so it was often done early in the morning, disturbing the local residents.
Flight 83: 8 August 1966 PEC at 35,000ft. PEC sorties at high altitude involved formatting with the A&AEE’s calibrated Javelin, XA778, under careful radar guidance. A photograph of the 221 was then taken, using a fixed, sideways-looking camera in the Javelin. The 221 was fitted with a special pitotstatic head that was insensitive to incidence. This was tested in flight on the 221 and on an A&AEE Lightning at Boscombe Down.
Flight 91: 18 August 1966 John Farley’s first 221 flight. Most of the 18 flights logged that month were intended for supersonic PEC calibration at altitude. During flying in August, Millward reported reheat difficulties.
Flight 94: 19 August 1966 A supersonic PEC flyby of the calibration Javelin, but Hawkes found himself above cloud with not enough fuel in the 221 to return to Bedford. His report said, “When I did pass the Javelin, I had used 2,796lb of fuel and my speed was Mach 1.4. I cut reheat, throttled back to flight idle, and, since I realised that I might not have sufficient fuel to reach Bedford, I told Bedford Radar of my decision to divert to Wyton. Th e descent was continued under Bedford’s control. I saw an airfield at eleven o’clock from me and since this lay between the setting sun and me, I could only just see it. Bedford confirmed that it was Wyton, and that I was clear to land. When I pressed the undercarriage down button nothing happened despite repeated attempts. I operated the undercarriage emergency lowering system, and almost immediately obtained three greens.
“At this stage, I was beginning to realise that the airfield was possibly Upwood. Since I was not able to raise the undercarriage again, I decided to land on what was obviously a serviceable, adequate runway rather than to fly to Wyton with the partial hydraulic failure and fuel consumption greatly increased by having the undercarriage down. It was not possible to droop the nose. I touched down about 100 yards from the threshold of the runway at 140kt and started moderate braking immediately. Th e nosewheel started to shimmy, but I found that the intensity of the shimmy was reduced if I held the stick back, and I did this for the rest of the landing run. I brought the aircraft to rest about 200 yards from the end of the runway and shut down the engine. I made safe the ejection seat and canopy, checked the wheels and released the parking brake. After shutdown there were 451lb of fuel remaining.
Rustin returned the aircraft to Bedford with the undercarriage locked down. He recalled, “I had a major fight in the late build stages of the 221 to persuade the authorities to fithe undercarriage emergency lowering system. Th e 221’s undercarriage system had some seven more sequence valves per side than the FD2 undercarriage system. Th e 221 would not have been likely to survive a wheelsup landing with such a high wing sweep, with it being likely to roll over as it slowed down but still going very fast! Jack Henderson did survive a one-wheel landing in the HP115 [on 20 November 1964] but that was only because it swung so rapidly after the wingtip hit the ground that the centrifugal force opposed the tendency to roll under the down-going wing. This was very, very lucky and unlikely to have been repeated in similar circumstances for the 221.”
Flights 96-102: 7-11 September 1966 Rustin and Millward practised for participation in the SBAC show and flew six demonstrations at Farnborough. The 221 was grounded for weeks on its return to Bedford. By then, a new versatile auto-stabiliser and an auto-throttle were undergoing ground tests before their installation. The versatile auto-stabiliser improved low-speed handling characteristics by varying some of the stability parameters. Its authority was very limited. The auto-throttle metered the precise amount of fuel needed to maintain a constant air speed.
Flight 103: 10 November 1966 The 221 took to the air again.
Flight 105: 21 November 1966 The reheat operated only after four failed attempts. It refused to function during the whole of flight 107, but was operated successfully during flight 108.
Flight 108: 30 November 1966 Start of a low-speed handling programme that covered crosswind landings and sideslip on the landing approach, as well as recovery from flight at speeds below the zero-rate of climb speed. Most of the tests were made in descending flight at a constant throttle setting. Because of the possibility of engine flame-out due to poor intake flow, a ram-air turbine was deployed at speeds lower than 135kt. The lowest speed attained during the programme was 114kt. Handling was acceptable but the aircraft appeared very ‘muddy’ and sluggish below about 125kt.
Flights 115-116: 11-12 January 1967 The 221 had a continuous voice radio transmitter, together with an ad hoc receiver in its chase Hunter (a legacy of the Bristol 188 project), but transmission was intermittent on these sorties.
Flight 120: 27 January 1967 A flight was cut short because of losses in cabin pressure. Another was cancelled before take-off on 14 February, and two sorties that month encountered failures of lights, compass and the reheat counter.
Flight 129: 15 February 1967 The 221’s last flight of the year, which completed the RAE’s Concorde validation program, amply demonstrating the suitability of the ogee wing for supersonic flight. At the end of 1967, a simulation of the 221’s low-speed handling was performed to validate the Concorde prototype design. Thirty-four sessions, totalling 27 hours, were flown by four Aero Flight test pilots who felt that, in general, a satisfactory simulation had been achieved and that the handling features that characterised the aircraft were well-represented.
Flight 130: 2 June 1968 The 221 embarked on a general programme of slender delta research.
Flight 133: 26 June 1968 The reheat nozzle stayed open after cancellation by pilot Millward. It closed after a second reheat selection and cancellation.
Flight 134: 4 July 1968 John Lewis made his first conversion flight on type.
Flight 144: 16 August 1968 With Lewis at the controls for one of his five flights in the 221 that month, again a reheat nozzle malfunction was encountered. Lewis recalled that the 221 was very short on fuel capacity, so to maximise the test time available the aircraft was always towed to the end of the runway for take-off. “Even then” he said, “we were hard put to get her to more than Mach 1.4, and on return there was fuel for one overshoot and circuit if the first went wrong, after which it was ‘land, like it or not’ just like the early Lightnings.”
A series of brief flight tests involving seven crosswind landings and 12 sidestep manoeuvres was carried out on the 221 in the second half of 1968, with the landings using the crabbing technique. Pilots reported no particular difficulty. Lewis wrote, “Th ese low-speed events were chased by a Hunter without saw-tooth leading edges, which therefore had a monumental pitch-up of its own, and truth to tell, the chase pilot had the more difficult task of the two to stay with the 221.”
Th e 12 sidestep approaches were made with progressively more severe sidesteps being introduced, until a maximum selected displacement of more than 400ft from the centreline at 300ft above ground level was reached. Generally between six and 12 seconds were needed from initiation of the corrective manoeuvre to completion of a good line-up, and a further eight to 10 seconds of straight run-in then remained to complete a landing. Th is was easier than anticipated in all cases, despite various combinations of poor visibility, crosswinds and, on two flights, low stratus on the approach at about 500ft. Rain during one set of approaches did not present as much difficulty as was expected and forward visibility remained better than from a Hunter in similar conditions.
Flights 146-148: 21, 26 and 30 August 1968 RAE test pilot Mike Laughlin converted to the 221.
Flight 149: 30 August 1968 A power failure resulted in Millward making an emergency landing. Flight 152: 31 January 1969 Lewis ended this sortie with a brake parachute landing.
Flight 154: 7 March 1969 Lewis reported that an aileron oscillation warning occurred at Mach 1.4 and 36,000ft. As a result, the aircraft was restricted to subsonic speeds, but oscillation warnings later appeared at subsonic speeds too.
Flight 155: 28 March 1969 Th e first of six flights observing surface pressures and structural strains resulting from fluctuations in the turbulent boundary. Lewis was at the controls.
The British-built Concorde prototype 002, G-BSST, made its maiden flight at Filton on 9 April. Its BAC pilots, Brian Trubshaw and John Cochrane, had flown the 221.
Flight 157: 9 April 1969 Th e brake parachute was inadvertently streamed.
Flight 158: 14 April 1969 Rustin’s last trip in the 221. He had covered the flight envelope from about Mach 1.56 down to 105kt.
Flight 163: 24 July 1969 RAE pilot John Pearce made his first 221 flight.
Flight 173: 14 September 1969 Th e cockpit pressurisation failed.
Flight 174: 13 November 1969 Millward completed the basic clearance of the 221’s Avon engine.
Flights 176A-B: 21 December 1969 RAE test pilot Ron Ledwidge converted to the 221.
Flight 177: 27 January 1970 Th e month’s only flight, by Lewis, was planned to make fluctuating and steady pressure observations but the reheat failed. It was retested in early February.
Flights 186-187: 28 February 1970 RAE test pilot Chris Wheal made his 221 conversion. Flights in February covered steady sideslips at various speeds and achieved Mach 1.45.
Flight 188: 21 July 1971 Lewis resumed 221 flying to assess the versatile auto-stabiliser in a programme that continued until the end of the 221’s career.
Flight 191: 26 July 1971 Canopy pull-out checks were carried out following this sortie and the ejection seat was inspected.
Flight 200: 27 August 1971 Th is milestone was attained during a satisfactory flight by Wheal.
Flight 202: 5 September 1971 Auto-stabiliser indicator problems necessitated a grounding that lasted several days.
Flights 217-221: 11-17 April 1972 In late April, RAE test pilot Ian Hamilton made his four conversion
flights on the 221. He recalled that the aircraft was “quite difficult to live with” the cockpit was “an ergonomic slum” and the lowspeed handling characteristics were deemed “interesting”
Flights 237-241: 15-22 September 1972 These sorties included the conversion of RAE test pilot John Rudin, who recalled that a nosewheel lock had been incorporated to counteract shimmy on take-off and landing, and to save putting another switch on the instrument panel it was wired in with the pitot heat switch. He wrote, “This could lead to embarrassing moments if you were a little late switching off the pitot heat after landing, because the aircraft would not turn with the nosewheel locked.”
Flights 242-247: 12-18 October 1972 Handling assessments with the aircraft in the approach configuration — nose drooped and undercarriage down — on straight-and-level flights and in turns. By then the aileron powered flying control units had been replaced by two-stage linearisedvalve units requiring significantly lower operating forces. This was a considerable improvement to the 221’s lateral handling characteristics at normal flying speeds.
Flight 247B: 22 January 1973 Trouble with the control surfaces was reported on this sortie, and caused a flight on 31 January to be called off. Thirty flights followed, mainly for auto-stabiliser assessment. One of them included air-to-air photography.
Flight 264: 30 March 1973 John Rudin displayed the 221 for visitors to RAE Bedford from the Society of Experimental Test Pilots.
Flight 284: 31 May 1973 Figures as recorded at the end of this sortie brought the total flying time of WG774, as both FD2 and BAC 221, to 330 hours 12 minutes including three hours on reheat, and 279 landings.
Flight 288: 4 June 1973 Ian Hamilton made the 221’s last flight. The 34-minute sortie, which landed back at Bedford, was satisfactory.
Offered for disposal, the airframe was allocated to the then Royal Scottish Museum and taken by road to its Museum of Flight at East Fortune on 6 November 1974. This loan lasted only a few years, for at the end of January 1980 the 221 was allotted to the Science Museum. After storage at Abingdon, WG774 made the move to RNAS Yeovilton in May 1980, going on display in the Fleet Air Arm Museum. It remains there, exhibited with Concorde 002 and HP115 XP841, witnesses to a great era in British aviation.
On 21 January 1976, Concorde fare-paying flights started with British Airways and Air France. While the wing of the 221 was not a direct scale of that of Concorde, the suitability of its ogee design was amply demonstrated by the BAC experimental aircraft. For instance, early studies predicted that the lateral control problems of Concorde would be associated with Dutch roll excitation following entry into turns at low speed. Flight experience with the 221 showed this was easily eliminated by coordinated rudder application. And, of course, Concorde’s droop nose is undeniable proof of its 221 lineage.
