The Jet That Flew Higher

In 1957, a British jet bomber flew higher than any aircraft before it. Nearly 60 years later, engineers are attempting to get this historic aircraft back in the air.
On 28 August 1957, the flight crew of an English Electric Canberra jet bomber climbed into their waiting aircraft, WK163, at a base in Luton, taxied onto the runway, and soared into the summer skies.
The Canberra had already enjoyed more than half a decade in the Royal Air Force (RAF), but this aircraft was different: it wasn’t operated by the RAF, but by the Royal Radar Establishment (RRE). This was an age of experimentation and technological great-leaps-forward, and the resilient and reliable Canberra was proving to be an excellent aircraft for such tests. In the last few years, Canberras operated by the RRE, and powered by ever-more efficient jet engines, had soared higher than any aircraft on Earth – as high as 65,889ft (20km).
But this Canberra would fly higher than any of those before.
WK163 had one special feature. Instead of the Rolls-Royce Olympus engines that had helped earlier Canberras climb to record height, this had something even more powerful – rockets. WK163 had been fitted with an experimental new powerplant, the Napier Double Scorpion, which was housed in the aircraft’s bomb bay. The idea was that the rocket’s extra thrust could help keep the aircraft aloft in the thin air found more than 60,000ft (20km) above the Earth’s surface, or even higher.
The pilot, Mike Randrup, flew with the rocket motor’s inventor, Walter Shirley, along for the ride. As they were expected to fly higher than previously thought possible, both wore pressure suits.
Randrup flew the plane up to 44,000ft using its normal engines, a pair of Rolls-Royce Avons mounted in the thick wings. He pointed the aircraft into a steep climb and turned on the rocket motor. The Canberra soared higher and higher, past 60,000ft… 65,0000ft… 70,000ft.
The aircraft was now heading into air so thin that the minimum speed need to keep it in the air – its stall speed – and the speed where supersonic shock waves started to form along its wings began to converge. The convergence could cause the plane to shake apart, miles above the English countryside. Randrup had to keep the aircraft in a 15mph window, all the while climbing steadily higher and higher.
Test pilots had a name for this convergence: they called it ‘Coffin Corner’.
The Canberra, however, did not shake itself to pieces. WK163 kept going until the altimeter showed 70,308ft (21km), a new world record. Randrup began the long descent back to base.
You could argue it was the closest Britain got to putting men into space.
WK163 might have flown higher than any aircraft before it, but it does not grace the collections of a famous museum – at least not yet. At the moment, it sits in a hangar near Doncaster in Yorkshire, partially disassembled. Its flying days look very much over.
But hopefully not for long. The Canberra is currently being exhaustively tested and examined in an attempt to get it back in the air by the same team who bought the massive Avro Vulcan jet bomber back from the dead, The Vulcan to the Skies Trust.
The Canberra is currently housed at Robin Hood Airport, a few miles outside Doncaster in South Yorkshire. When BBC Future visits, it is a murky, overcast day. The stratosphere WK163 journeyed to the edge of is hidden behind a blanket of clouds.
Andrew Edmondson, the trusts engineering director, shows BBC Future around the Canberra, which looks like a giant model kit that’s been abandoned halfway through assembly. Just a few feet away looms the massive Avro Vulcan, the 1950s-era nuclear bomber that the trust spent the best part of a decade toiling to get back into the air.
This is their next prize, returning a Canberra back to flying displays in the UK. Some 800 served with the RAF from the 1950s until, for a few specialised reconnaissance models at least, the mid-2000s. None of the few flying examples are based in the UK, however.
“The whole direction of the restoration is to fully overhaul the aircraft,” says Edmondson.
The Vulcan to the Skies Trust had wanted to turn their attentions to another aircraft restoration project after the Vulcan flew for the last time. (The Vulcan retired from flying in 2015 because it could no longer get the manufacturer’s engineering support to keep it in the air).
This record-breaking Canberra had been flying as recently as 2007, after it had ended its official service. It was painted in grey and black to make it stand out more in flying displays, and was operated by Classic Flight out of Coventry Airport since 2000. It was only grounded when it suffered engine problems. Since 2007, it had mostly been stored in the open at Coventry – not ideal conditions to preserve an aircraft.
“We went and saw the aircraft, and did a very quick inspection, and saw that the aircraft was in very good condition,” Edmondson says.
The team now has to face the challenges of bringing a 1949-era airframe – the Canberra was designed in the final days of World War Two – back into the air.
One of the biggest headaches such restoration projects face is finding spare parts that are still mechanically sound enough to be used in a flying aircraft. When you’re dealing with an aircraft as old as a Canberra, that may prove impossible, so parts have to be reverse-engineered. But that is an incredibly complex task, requiring parts to be built from as close to the original parts as possible. Make them too weak and they might fail far more quickly than they should; make them too strong and they can cause damage to other parts of the aircraft around them.
That will require WK163 to undergo a full inspection – something that will take a lot of time.
“This is really important when you’re dealing with critical life components,” says Edmondson. “That’s any part that’s affected by fatigue or pressure, and that has to be removed.”
There’s another issue with airplanes like the Canberra, which served in some air forces for more than four decades, long after the production lines had closed down. Different customers would come up with different solutions to their particular needs – and all of those would be classed as a new modification to the existing aircraft. When you have an aircraft that was built in such numbers and served for so long as the Canberra, it can be quite the paper chase to work out just which modification it is, and how those modifications would have affected the airframe.
“We have to go through a full stress test,” says Edmondson, which is why the plane sits in pieces.
BBC Future got to nose around the two-person cabin, in which Randrup and Shirley had undertaken their momentous flight. It’s been stripped of everything – from the seats to the instrument panel, and all that wiring that connected the instruments to the aircraft – as Edmondson’s team prepare for the slow and methodical process required to get the old bomber back into the air.
Edmondson says the smaller, more compact Canberra is just as an important part of Britain’s aviation heritage as the enormous, crowd-pleasing Vulcan. So much was learnt about flying jet aircraft with the Canberra, he says, because the airplane was so stable and so easy to fly. That’s one of the reasons it was a natural choice to test Napier’s rocket booster.
And, Edmondson says, the Canberra was such an important aircraft that it’s a major oversight that none are currently flying in the UK.
“It’s a really popular flying airplane, and pilots enjoyed flying it because it’s such a ‘pilot’s airplane’. When it took over from the RAF’s Mosquito bomber, they were putting the same pilots into it, and that must have been a major change – like going from a Ford to a Ferrari.
“The Canberra flies like a fighter plane,” he says – with its two Avon engines at half-power, the Canberra could outrun the latest models of Spitfires with ease; a Mark 24 Spitfire could easily reach 450mph (724km/h).
The renovating will take four stages. There is an initial inspection, rectifying any mechanical faults, testing and clearance for operations; stage two will begin in 2017, and the final stage should, funds permitting, be in 2018, in time to celebrate the RAF’s 100th anniversary. “By then, we expect to be flying the Canberra for 60 to 80 hours a year, and 30 to 35 of those will be in flying displays. It’s a good target to aim for.”
The Canberra won’t be able to fly to the heady heights reached by Randrup and Shirley; the aircraft won’t be pressurized, so it will only be able to fly up to 15,000ft (4.5km) high. The cockpit will have to be updated to a more modern standard to ease the pilot’s workload – all the more important when you consider that even the youngest Canberra pilots will be well into their 50s by the time WK163 gets back into the air.
“One thing we have to decide is whether we put a ‘rocket engine’ back in the bomb-bay,” says Edmondson. “We do have a dummy wooden version of it we could use.” He smiles. “And the bracket that the original was fitted to is still in there.”

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