by Damien Burke
Press reaction to the first flight was generally positive but muted; Raymond Jackson could be relied upon to raise a smile, however. Evening Standard
With XR219’s engines replaced by new units, and Beamont’s refusal to accept further flights with the 98 per cent thrust limitation, a plan was instigated to allow the use of 100 per cent thrust for brief periods, such as during take-off. Strict conditions were to be put in place; both engines would have to have LP shafts of known history and low usage; both would be strain-gauged and stresses on the shafts recorded at all times; and finally a visual indicator in the cockpit would show when stresses on the shafts exceeded 10 tons/sq in (1,575kg/sq cm), well below the breaking stress. This plan was put to the MoA at the end of October 1964, and was accepted. Warning lights were soon installed in XR219’s cockpit, linked to amplifiers hooked up to the strain gauges on the engines’ LP shafts. Beamont was not entirely comfortable with these, being well aware of the unreliable behaviour of amplified low-voltage signals, but accepted that this was the only way forward.
Flight 2, blighted by intolerable engine vibrations, did not last long. The aircraft’s distinctive contrails were a product of the fierce vortices spun off the wingtips at even relatively low angles of incidence. BAE Systems via Warton Heritage Group
Emergency landings
The second flight of XR219 did not take place until the end of the year, on 31 December (the aircraft was ready on the 23rd, but poor weather intervened), and was cut short owing to intolerable vibrations throughout a large portion of the rpm range on the port engine. At its worst the crew’s eyeballs were vibrating so much that vision was lost, and Beamont quickly returned the aircraft to Boscombe, keeping the undercarriage down again while he burned off fuel to a safe landing weight. With a somewhat firm arrival on terra firma there was severe undercarriage-induced lateral vibration, sufficient to throw the crew about to the extent of their harnesses.
No immediate cause was found for the engine vibrations, and another taxy run proved inconclusive. Some modifications were made to the undercarriage, with hop-damper pressure reduced and the toe-out of the bogies slightly reduced. With wary eyes on the all-important engine LP driveshaft warning lights, flight 3 went ahead three days later. At a critical point on the take-off run the warning light for the No.1 engine flickered, but Beamont was now committed to the take-off. In the climb, both engine warning lights came on steadily and the intolerable engine vibration also returned in full force. Carefully keeping the engines away from the range that could result in the LP shafts disintegrating, and trying to stay clear of the range giving the worst vibration, Beamont made an immediate emergency landing. Things were not going well for the flight test programme.
Flight 3 was similarly cut short by engine LP shaft stress warning lights illuminating, and more engine vibrations. BAE Systems via Warton Heritage Group
The TSR2’s large airbrakes were effective, but troubles with the actuating jacks and synchronization mechanism meant that XR219 flew with them cracked open slightly for most flights, and a redesigned mechanism was on the cards for production aircraft. Here, on Flight 4, they are exercised to their full travel for the first time. BAE Systems via Warton Heritage Group
The double LP shaft warning turned out to be a false one, caused by a poorly fitted power supply connector. (Beamont ordered the lamp filaments to be removed from the warning lamps as he considered them a useless distraction; from now on only the navigator’s lamps would be operative.) To solve the engine vibration problem, the port engine and jetpipe were replaced, though the cause ultimately turned out to be a faulty fuel pump. Various other minor defects were dealt with, and a camera was mounted on the nose gear leg to film the main undercarriage at touchdown. White stripes were painted on the mainwheel tyres to aid cine film and photographic analysis.
The next flight was made just under a week later. After a frustrating morning in which it was thought the flight would have to be cancelled because the flight test radio frequency was being blanketed by heavy interference (some of the team even thought there was some kind of jamming effort under way by opponents of the project), Boscombe gave permission to use its own tower frequency, as there was expected to be little or no other traffic. The longest flight so far was carried out, a whole 21min in duration, including the use of various flap and airbrake settings. A very gentle landing was made and the undercarriage oscillations experienced on previous flights were much reduced. Beamont was fulsome in his praise of the aircraft’s handling qualities in the approach and landing configuration.
Undercarriage retraction problems
Flight 5 saw the first attempt to retract the undercarriage, after ten consecutive successful retractions in the hangar. On this flight the nose gear camera had been removed and replaced by one on the fuselage, looking down at the port main undercarriage to give another angle on the oscillation problems experienced at touchdown. Unfortunately things did not go well. After a succession of thudding and clunking noises in XR219, the pilot of the chase aircraft reported that the port main gear had stayed down. Inspection through the navigator’s periscope revealed that the bogie had failed to rotate fully, thus blocking the retraction sequence. Beamont extended the undercarriage again, but now the starboard bogie failed to rotate to the landing position, and the port bogie had also stayed where it was. None of the emergency drills included the case in which the gear was down but the bogies were at the wrong angle, so the flight test team on the ground was consulted. They felt sure that a gentle touchdown would result in the bogies rotating to the correct position. Beamont offered his navigator, Don Bowen, the chance to eject, but Don elected to keep him company and the aircraft’s remarkably precise controls enabled Beamont to carry out a perfectly judged landing at minimal descent rate. The bogies rotated to the normal angle and the landing was successful; and with far less of the disorienting oscillations previously experienced.
After another undercarriage-down flight to familiarize Jimmy Dell with the aircraft, flight 7 was the next attempt to retract the undercarriage. Various changes to the gear had been made by BAC Weybridge to overcome the bogie rotation problem, and twenty-one consecutive successful retractions had been carried out in the hangar. During this flight, after selection of undercarriage up, the port gear successfully retracted. Unfortunately the starboard gear did not. The bogie had rotated to align with the main leg, but had not tilted to match its angle, and once again the sequence came to a halt. This time the selection of undercarriage down was more successful, and the bogies rotated to a nearly level attitude, enabling a normal landing to be made. Jimmy took flight 8, with no attempt to retract the gear, and flight 9 was back to Beamont for assessment of handling with 50 degrees of flap and no gear retraction. Before flight 10 further modifications had been made to the undercarriage, which then finally retracted successfully in the air. Beamont took the opportunity to ‘widen the flight envelope’, or ‘snot the airfield’ in RAF parlance, taking the aircraft up to 500kt (575mph; 925km/h) and then making low passes over Boscombe at 450kt (520mph; 835km/h) just 100ft (30m) above the ground. While the chase aircraft were reporting moderate-to-heavy turbulence, the TSR2’s cockpit was a smooth and calm environment.
The first attempt to retract the undercarriage in flight, during Flight 5, resulted in the port main gear leg failing to retract. BAE Systems via Warton Heritage Group
When the gear was extended again, neither bogie rotated to the landing position and a careful ‘tip-toe’ landing had to be made. BAE Systems via Warton Heritage Group
Jimmy Dell in the cockpit of XR219 before his first flight in the TSR2. Jimmy soon took over from Roland Beamont as lead pilot on the TSR2 programme, and by the time of cancellation he had the most hours on the aircraft.
Jimmy Dell’s first flight, on 15 January 1965, was a familiarization sortie with no attempt made to retract the undercarriage. Visible in the background here are Thruxton Airfield (bottom right) and Tidworth (top centre). BAE Systems via Warton Heritage G
roup
The second attempt to retract the undercarriage in flight, during Flight 7, resulted in the starboard main gear leg failing to retract. BAE Systems via Warton Heritage Group
One of a recently rediscovered sequence of superb air-to-air photos taken over a snowy landscape on Flight 7 shows the result of the undercarriage malfunction, leaving the bogies at the wrong angle, though much closer to normal position than on Flight 5. BAE Systems via Warton Heritage Group
Ironically, the ‘wrong’ bogie position experienced during Flight 7, on later analysis, was found to assist with reducing vibrations on landing. BAE Systems via Warton Heritage Group
On final approach to a wintry Boscombe Down. The TSR2’s stability and controllability in the landing configuration was often praised by the pilots, and was the product of a great deal of hard work at the design stage. BAE Systems via Warton Heritage Group
A careful landing at the end of Flight 7, though much less stressful than that of Flight 5. An eventful first flight for navigator Peter Moneypenny, nonetheless! BAE Systems via Warton Heritage Group
Taken during Flight 8, this photo well depicts the large size of the tailplane. Tailplane power was significantly higher than predicted by simulation work. BAE Systems via Warton Heritage Group
Jimmy Dell and Peter Moneypenny arrive back on runway 24 at Boscombe after Flight 8. Jimmy remarked in his experimental flight report that ‘… the overall impression was of a straightforward, uncomplicated aircraft from the handling aspect …’. BAE Systems via Warton Heritage Group
Flight 9 was a brief assessment of handling with flaps down at 50 degrees. The results were generally good, though significant buffet at this flap setting warranted further investigation. After landing, Beamont recorded nil defects, a first for the aircraft, but this ignored several defects present during the flight, such as a misreading attitude indicator and, of course, the non-functioning undercarriage. BAE Systems via Warton Heritage Group
Before any attempt was made to retract the undercarriage in flight, multiple cycles were carried out with the aircraft on jacks in the hangar at Boscombe Down. These tests, however, were unable to simulate the air loading on the assembly, and various modifications were needed to achieve a successful retraction in the air. BAE Systems via Brooklands Museum
Jimmy Dell and Peter Moneypenny carried out some further low-level, high-speed flying on the next flight, again reporting smooth conditions while other aircraft reported turbulence, and two days later Don Knight got his hands on the aeroplane for the first time. After an uneventful flight, Don had the misfortune to land heavily and the aircraft bounced dramatically. Severe and disorienting oscillations coupled with the bounce made for a close call, and once the aircraft had been stopped it was inspected to see if it was safe to taxy back to the hangar. Some damage was evident, so it was towed, and repairs meant that the next flight did not take place until six days later.
Flight 13 was the first flight to take the aircraft to medium altitude, 28,000ft (8,500m) and Mach 0.95, and gave the flight-test team the confidence needed to plan the next flight as the departure from Boscombe and delivery to Warton, where the real flight-test programme could get under way. The TSR2’s presence at Boscombe had not been a pleasant experience for everybody involved. It was disruptive to the A&AEE’s normal schedules, the BAC staff were all working many miles from home (particularly for those from English Electric), and even minor problems resulted in days of wasted time while parts were sourced and transported from afar. Furthermore, in November 1964 the MoA had informed BAC that the A&AEE would be unable to offer further facilities beyond the third aircraft; apparently under the impression that BAC actually wanted to be there! Needless to say, BAC was delighted to find out that it would soon be able to control its own destiny when it came to flight testing of the TSR2.
Flight 10, and the undercarriage is successfully retracted. By this point in the programme the auxiliary intakes were linked with the undercarriage, and closed when the gear was up. Beamont wasted no time extending the limits of the flight test envelope, taking the aircraft up to a maximum 500kt (575mph) and simulating a low-level attack run over Boscombe Down at 450kt (520mph) and 100ft (30m). BAE Systems via Warton Heritage Group
The undercarriage drop-test rig at Weybridge. Unfortunately such a rig was unable to simulate the actual sequence of events that occurred when the aircraft touched down, and a combination of spin-up drag and interactions between the various components of the undercarriage led to often violent oscillations on touchdown. BAE Systems via Warton Heritage Group
Navigator Peter Moneypenny and pilot Don Knight, the crew for Flight 12. Don found that XR219 performed more like the variable-stability T-33 he had flown in the USA than the fixed-base simulator at Weybridge, though both lacked the ‘big aircraft’ feel of the TSR2 itself. BAE Systems via Warton Heritage Group
Flight 14 was thus the flight that made everybody happy. Roland Beamont and Peter Moneypenny took XR219 up to 30,000ft (9,000m) for the transit up north, taking the opportunity to carry out a supersonic run along the Irish Sea and reaching Mach 1.12 with ‘no fuss’ whatsoever. Shortly after reaching Mach 1.0 on dry power only, Beaumont lit a single reheat, initially on the minimum setting, and accelerated away from the Lightning chase aircraft, and its pilot had to use full reheat on both engines to catch up. At Warton just about the entire workforce had gathered by the hangars to greet ‘their’ aircraft, and after an instrument descent Beamont made a high-speed low-level run across the airfield, 460kt (530mph; 850km/h) at 150ft (46m), followed by another, slower pass before setting up for a landing on runway 08. After this flight Beamont noted that stability and control were of very high quality, transonic handling in particular being superior to that of any other aircraft he had flown. Undercarriage oscillation on landing, however, had been severe once again.
The last of the TSR2 flight crew to get his hands on the aircraft was navigator Brian McCann, seen here at Boscombe in front of XR220. BAE Systems via Warton Heritage Group
Holding a 40-degree banked turn at Mach 0.9 with 86 per cent power during Flight 13. This flight proved that XR219 was more than up to the transit to Warton, Jimmy Dell and Don Bowen taking it up to 28,000ft (8,500m) and Mach 0.95, and making radio contact with Warton from a distance of 180nm (200miles; 320km). The type’s aerodynamic performance was beginning to be appreciated by this point, with power settings 5 per cent less than predicted being necessary to hold any given Mach number. BAE Systems via Brooklands Museum
Flight 14 saw XR219’s departure from Boscombe Down and transit to Warton. On the way the decision was made to use the Irish Sea supersonic Test Run ‘A’, and with dry power only (95 per cent) XR219 nudged through Mach 1 with no drama whatsoever. When reheat was lit on the port engine only, the aircraft accelerated quickly to Mach 1.12 at 30,000ft (9,000m), the highest speed the type would ever record, leaving the Lightning chase aircraft behind in the process, until it caught up using reheat on both engines. BAE Systems via Warton Heritage Group
Arrival over Warton at 150ft (45m) and 460kt (530mph; 850km/h), control being ‘smooth and precise, and no disturbance was felt from turbulence’. The TSR2’s ride quality at low level exceeded all expectations. BAE Systems via Brooklands Museum
‘Home’ at Warton, from where all remaining test flights were flown. This was a big event for the workforce, hundreds of employees being allowed to down tools to watch XR219 arrive. BAE Systems via Warton Heritage Group
One of the most commonly published TSR2 photographs is this one, taken at 12,500ft (3,800m) on Flight 17, with Cumbria in the background. This was the first flight with the airbrakes fully closed. The problems with jack backlash and synchronization were not cured; the airbrakes had simply been locked shut and disabled to permit performance measurements at higher speeds. BAE Systems via Warton Heritage Group
Undercarriage oscillation problems
After the shattering lateral oscillations experienced on landing after the first flight, there was ver
y little hard data available with which to diagnose the problem, despite the mass of instrumentation in the aircraft and all the recordings generated by that flight. After three further flights and examination of film from the cameras now mounted on the aircraft and pointing at the main undercarriage, BAC was virtually certain that the cause of the oscillation was a torsion-bending vibration of the undercarriage, excited by spin-up drag at the wheels. The rear wheel contacted the ground first, but did not spin up to speed as fast as expected, tending to ‘skip’ over the runway in the brief period before the front wheel on the bogie touched down. Rapid spin-up of the pair of wheels then made the bogie yaw sideways, dragging the wheels and bogie to the side and setting off the lateral oscillations. Only when the aircraft’s weight was firmly on both sides of the undercarriage did these die down. This was bad enough, imposing severe side-loads on the undercarriage, but the results in the cockpit were another matter. The resonant frequency of the fuselage was similar to that of the undercarriage, and coupling of the fuselage and undercarriage frequencies resulted in the oscillations becoming a violent vibration at the cockpit, lateral accelerations of up to 2.1g being experienced.