It looked like a four-poster bed welded out of scaffolding, and it flew by balancing on a column of jet blast. When the Rolls-Royce Thrust Measuring Rig lurched into the air at Hucknall in 1954, it became the first jet-lift aircraft to fly anywhere in the world — and it looked so absurd that the engineers who built it simply called it the Flying Bedstead.

Behind the comedy was a serious problem nobody had solved: could a jet aircraft hover on its own thrust and be controlled while doing it? The Bedstead answered yes, and in doing so it lit the fuse for every British vertical-takeoff aircraft that followed, right up to the Harrier.

Two engines and a lot of nerve

The rig was brutally logical. Two Rolls-Royce Nene turbojets were mounted horizontally, facing away from each other, their exhausts bent through 90 degrees to blast straight down through the machine’s centre of gravity. To keep the whole contraption from tipping over, engineers bled about a tenth of the engines’ compressed air out to small “puffer” nozzles at the extremities — jets of air that pushed the frame level, like a tightrope walker’s pole made of compressed gas.

On 3 August 1954, Rolls-Royce chief test pilot Ronald Shepherd made the first free flight. The rig rose, hovered, edged sideways and backwards, and set back down — unremarkable moves for a helicopter, revolutionary for a jet.

Rock steady — most of the time

With its autostabiliser working, pilots found the Bedstead uncannily calm in the hover. But it was not tame. The hardest part was controlling height, because the big Nene engines were slow to respond to the throttle, so a pilot chasing altitude could easily get behind the machine. Roll control, too, was marginal.

The crash and the cost

Two rigs were built, and pioneering flight research is rarely bloodless. The second machine crashed in 1957 during a tethered hover, killing its pilot, and Rolls-Royce’s own flying with the type came to an end. But the data had already been gathered, and the central question — can a jet hover under control? — had been answered beyond doubt.

What the Bedstead started

The Bedstead’s reaction-control idea — puffer jets at the wingtips, nose and tail to steer an aircraft too slow for its normal controls to bite — became the key to everything that followed. It fed directly into the Short SC.1, Britain’s first fixed-wing VTOL aircraft, which used a battery of lift engines to rise and a separate engine to fly forward.

The SC.1 proved that a machine could transition from hovering to winged flight and back. But carrying a stack of engines just for take-off was a dead end. The breakthrough came when Hawker fitted a single vectored-thrust engine to the P.1127, the aircraft that matured into the Harrier — the world’s first operational jump jet, and still the most famous. Every one of them kept the Bedstead’s puffer jets for control in the hover.

Not bad for a flying bedframe.

Sources: Wikipedia; Rolls-Royce / Aeronautical Research Council R&M 3336; Science Museum Group; The Engineer; Dunsfold Airfield History Society.