On 30 May 1949, about 5,000 feet over Warwickshire, John Oliver Lancaster put an Armstrong Whitworth A.W.52 into a shallow dive and the aircraft began to shake. Not a buffet — a violent asymmetric flutter of the elevons and wingtip fins, roughly one and a half to two cycles a second, hard enough that he could no longer read the instruments or reliably work the controls.

He pulled the blind. He was the first British pilot ever to eject from an aircraft in an emergency, and he became the first life saved by a Martin-Baker seat — a company whose seats have since saved more than 7,000 people.

A wing built to an accuracy of two thousandths of an inch

The A.W.52 existed to answer one question: could you get genuine laminar airflow over a large wing in real conditions? If you could, drag would collapse and an airliner might cross the Atlantic on a fraction of the fuel. Armstrong Whitworth was sketching a flying-wing transport of 180,000 to 200,000 lb with its engines buried in the centre section.

To find out, the company built the wings from the outside in, forming the skins first over accurate moulds so the finished contour was held to about two thousandths of an inch. It was some of the most precise airframe work done in Britain at the time.

It did not work. Surface accuracy in the hangar is not the same as surface accuracy in service, where rain, insects, dust and ordinary handling disturb the boundary layer. The A.W.52's central finding was a negative one, and an important one: laminar flow at this scale was not achievable with the manufacturing and maintenance of the day.

The glider first

Before either jet flew, Armstrong Whitworth built a wooden two-seat glider, the A.W.52G, at roughly 0.6 scale with a 53 ft 10 in span and anti-spin parachutes at the wingtips. It first flew on 2 March 1945, towed aloft by a Whitley bomber, to prove the tailless layout would fly at all before anyone bolted engines to it.

The full-size aircraft followed: TS363 on 13 November 1947 with two Rolls-Royce Nenes, then TS368 on 1 September 1948 with the smaller Derwents. Note that the two prototypes had different engines — a detail that gets muddled constantly, along with which one Lancaster was flying.

British Pathé footage of the A.W.52G glider — the wooden proof-of-concept that came first.

Thirty seconds in May

Lancaster was on only his third flight in the type. The design speed had been quoted at 500 mph, but flutter had already forced a practical limit of about 300; he was doing roughly 320 in the dive when it started.

His reasoning, as he told it afterwards, was that if the aircraft did not come apart he would shortly be unconscious — so the seat was the only option left. He fired it on a Martin-Baker pre-Mk.1, landed near the Cuttle Inn at Long Itchington, and came away with a chipped shoulder bone and a compression fracture of the upper vertebrae. Local newspapers reported him uninjured. He was not.

What happened to the aeroplane afterwards is genuinely disputed. The most common account has the flutter ceasing once the weight came out of the cockpit, the pilotless aircraft gliding down and coming to rest in open country near Leamington Hastings with relatively little damage. Other records simply list it as destroyed. It was written off either way.

A fuller account of the programme, the layout and the flutter problem that ended it.

What it was actually for

Armstrong Whitworth abandoned the flying wing soon afterwards and put its effort into the AW.55 Apollo airliner. TS368 went to the Royal Aircraft Establishment at Farnborough and was scrapped in June 1954. Neither aircraft survives; there is not even a museum airframe, only a model at Coventry.

It is tempting to file the A.W.52 as another handsome British failure, and on its stated objective it failed. But research aircraft are supposed to produce answers, not products, and it produced two: that laminar flow was not going to save the airliner, and that a British pilot could survive leaving a disintegrating aeroplane at 300-odd mph. The second answer has been worth rather a lot since.

Sources: Oliver Tapper, Armstrong Whitworth Aircraft since 1913 (Putnam); IBCC Digital Archive oral history with Jo Lancaster, 2015; Martin-Baker company history; Aviation Safety Network; Warwickshire Industrial Archaeology Society; airscape Magazine; Historia de la aviación (2018); Wikipedia cross-checks.