How world’s fastest bird will make aircraft of the future safer

British scientists are examining how the world’s fastest bird flies to inspire new technologies to make aircraft safer.

The peregrine falcon can reach speeds of up to 390km/h.

The designer of the British World War II fighter, the Spitfire, is said to have based the elliptical shape of the aircraft’s wings on the wing shapes of gulls he watched soaring over his nation’s coastal cliffs.

That may be a myth created by the producers of the 1942 film, The First of the Few, and it’s more likely the brilliant R J Mitchell chose the shape to accommodate the four machineguns the Royal Air Force wanted in each wing.

But now British scientists are examining how the world’s fastest bird flies to inspire new technologies to make aircraft safer, more aerodynamically effective and more fuel efficient.

The scientists from BAE Systems and City, University of London, are investigating how the peregrine falcon is able to stay in control and airborne at speeds of up to 390km/h, even in high winds.

The scientists say that when a peregrine falcon dives at high speeds, its body is subjected to forces that are very sensitive to small changes in its angle of attack.

If the bird exceeds its optimum angle by a very small margin, feathers at the rear of its wings start to vibrate. These vibrations are detected by nerves in the body, warning the bird that it may be about to take a tumble and fall from the sky.

Inspired by this natural phenomenon, engineers are developing “sensory feathers” which are 3D-printed polymer filaments which would act like sensors on the body of an aircraft, providing early warning if it began to stall. These filaments gather real-time air flow data and can quickly alert the pilot to take action and avert possible disaster.

More densely packed passive polymer filaments may also be able to change the airflow very close to the surface of the aircraft which could reduce the aerodynamic drag on the wing’s skin which slows the aircraft’s flight.

The falcon may also provide clues on how an aircraft can be made to land safely at slower speeds. When falcons and other birds slow down to land at low speeds after swooping, some of the feathers on the upper surface of their wings lift upwards. The effect of this feather “ruffling” also helps them to maintain the lift on their wings at high angles of attack and fly more slowly or manoeuvre more aggressively. Small, flexible flaps attached to an aircraft’s wing could allow it to fly at lower speeds to land in a shorter distance or be more agile in manoeuvring to avoid obstacles in mid-flight.

Small, flexible flaps attached to an aircraft’s wing could allow it to fly at lower speeds to land in a shorter distance or be more agile in manoeuvring to avoid obstacles in mid-flight.

The bird stabilises itself after swooping or landing by ruffling its feathers so the designers are considering adding small flexible or hinged flaps to an aircraft’s wings to allow it to remain manoeuvrable while flying slowly.

The scientists say the added safety margin could allow future aircraft to be built with a more compact design or to carry more fuel. The flaps may decrease the noise an aircraft makes by lowering the acoustic signature of the flow around it.

They say the emerging technologies could be built into aircraft within 20 years.

Professor Christoph Bruecker, from City’s aeronautical engineering department, said the peregrine falcon was able to dive and intercept its prey at incredibly steep angles and high velocities and the research was delivering real innovation and benefits for the aerospace sector.

Brendan Nicholson is defence editor of the Australian Strategic Policy Institute site, The Strategist.