Gust generator lightens bumpy flights for aircraft manufacturers

The generator – the first of its kind in the world capable of producing gusts at transonic, or cruising, speeds – has been developed by the Aircraft Research Association (ARA) with funding from the Aerospace Technology Institute.

The device, which has been installed within the ARA’s high speed wind tunnel at Bedford, could also allow manufacturers to design lighter aircraft wings, according to Peter Curtis, the organisation’s chief technology officer.

“There are fairly conservative assumptions made when designing aircraft, about the size of gusts and how they will affect the aeroplane, because people simply don’t know enough about them,” he said. “One of the results of that conservative approach is that wings are potentially heavier and stronger than they need to be.”

By improving the industry’s understanding of how gusts interact with the aerodynamics of aircraft, they hope the generator will allow manufacturers to design lighter, more fuel efficient aeroplanes equipped with more effective gust alleviation technology.

The generator consists of two large vanes located upstream of the aircraft model to be tested. These vanes blow air over their trailing edge, altering the angle of attack and thereby producing lift, said Curtis. This lift in turn induces a downwash over the vane that changes the angle of attack over the aircraft – the equivalent to a gust of wind.

“We are able to simulate a single gust, or what you might feel when you are cruising along and get an individual bump, rather than the continuous turbulence you can experience,” he said. “But obviously continuous turbulence is just a series of bumps.”

The aircraft models are coated in a special pressure-sensitive paint. This allows the researchers to measure the rapidly changing pressure across the entire aircraft, rather than the discrete points possible when using individual sensors.

The researchers have so far demonstrated that the generator can produce short 25 millisecond gusts, the duration of blasts aircraft travelling at cruising speeds are likely to be subjected to.

They now plan to focus on generating different shaped gusts, to allow them to investigate how this affects the aerodynamics of aircraft.

The organisation also has interest from Airbus and a number of other airframe manufacturers interested in testing their own aircraft in the tunnel.