An advantage of active flow control is that it has the potential to allow for maneuvers that are impossible sans conventional controls, according to David Williams. (Image:

A research team at the Illinois Institute of Technology has for the first time demonstrated the use of a novel control method in a tailless aircraft. The technology allows an aircraft to be as smooth and sleek as possible — making it safer to fly in dangerous areas where radar scans the sky for sharp edges.

Conventional aircraft rely on protruding fins for steering, but this tailless design is controlled by active air flow in which jets of air are blown onto different surfaces of the aircraft body, corresponding to the aircraft’s direction. The technology has potential to make commercial airplanes more fuel-efficient.

Professor David Williams led the team in the construction of a jet that houses both conventional steering controls and a novel implementation of active flow control. Last October, the group launched the jet from the Pendleton Unmanned Aircraft System (UAS) Range in Oregon for a pair of nine-minute flights that proved the system’s worth.

During each flight, one pilot launched the jet using conventional flight controls. Then, midflight, they switched control to a second pilot who operated the active flow control system.

In the first test, the team found that the active flow control system provided more power than had been predicted from wind tunnel tests.

“In engineering, it never works that way, you almost always get less than you were hoping for, but in this case, we got more,” said Williams. “The first day was very dramatic. It was very strong and very scary. If the jet gets too far over on its side, it could spin out of control. In fact, it did go over to 90 degrees, but it recovered.”

An advantage of active flow control is that it has the potential to allow for maneuvers that are impossible sans conventional controls, including very fast turns and the ability to fly at angles that would cause conventional controls to become ineffective.

The unexpected power of the system has increased confidence that they’ll be able to do these more advanced maneuvers with this jet, Williams said.

During the second flight, Williams reduced the power to the active flow control system for a safer, more stable flight, allowing for the collection of more data about how the active flow control was operating. The active flow control is implemented via patent-pending Coanda valve designed by Williams and his students.

The team will be conducting more flight tests, gradually building toward using the active flow control during takeoff and conducting more extreme control maneuvers, Williams noted.

“We’ve made the breakthrough that I was looking for,” said Williams. “Now future tests will start adding to the accomplishments and confidence in the airplane’s design.”

For more information, contact Kevin Dollear at This email address is being protected from spambots. You need JavaScript enabled to view it..