Body Freedom Flutter Research Program


The desire to fly higher, farther, faster, and more affordably has always been a challenge. One barrier to doing so has always been flutter, the potentially catastrophic dynamic coupling that can occur between the elastic motion of the aircraft wing structure and the aerodynamic loads acting on it. The resulting vibration can quite literally break a wing or tail surface off an aircraft.

In 2005, a small team of engineers from the Skunk Works® decided to tackle this issue by creating a new design methodology. The resulting Body Freedom Flutter (BFF) research program proved this behavior can be accurately predicted and addressed through the creation of a new design paradigm of active control. This active control method produced a 75 percent increase in BFF speed, as proven in a series of flight tests.

The BFF program led to the development of the X-56A Multi-utility Aeroelastic Demonstration (MAD), an innovative modular unmanned air vehicle designed to test active flutter suppression and gust load alleviation. The X-56A demonstrator will test to the edge of the flight envelope where flutter occurs.

These technologies are considered vital for the successful development of the slender, lightweight, high-aspect-ratio wings that could be used by future transports as well as intelligence, surveillance and reconnaissance Unmanned Aerial Systems (UAS).