Air Force Experimental Drone

posted 5 Mar 2012, 21:09 by Evert Bez   [ updated 5 Mar 2012, 21:22 ]
Flutter kills. When a vibration, usually in an aircraft’s wing or tail, matches the natural frequency of that structure, the results of that “flutter” can be catastrophic. If the vibration isn’t dampened over time, it can grow, causing the structure to flex uncontrollably and potentially fail.

Aerodynamic Flutter is usually applied to wings or ailerons and is the unstable oscillation caused by interaction between aerodynamic forces, elastic reactions in the structure and the force of inertia. Unless damped quickly flutter will break a wing. The cure for flutter is usually to dispose the weights so that the centre of gravity of the wing is as far forward as possible.

The X-56A (left) , developed with Lockheed Martin’s famed Skunk Works, is a modular drone designed to test an unusual method of alleviating flutter in lightweight aircraft. Rather than relying upon structural strength to keep the wing in one piece, it uses computing power.

Powered by twin JetCat P240 turbojets, and configured for easy wing replacement, the aircraft will be tested with stiff wings as well as multiple sets of flexible wings. The design also includes a hard point on the center upper deck of the aft fuselage that can either be adapted to house a third engine or the boom for a joined wing, thereby enabling testing of more advanced aerodynamic concepts.

With a wingspan of just 28 feet, the X-56A is a small-scale version of current high altitude unmanned aircraft.

Read Full story here at WIRED or alternatively at Wright Patterson Air force page