GUY NORRIS / LOS ANGELES
Lockheed Martin's Palmdale, California-based Skunk Works is starting work on shape-changing technology for next-generation military aircraft under the US Air Force's morphing aircraft structures programme. Lockheed Martin's $9.3 million contract was awarded in parallel with a $9.6 million computer simulation contract given to California-based HyperComp.
The USAF's goal is to develop a vehicle capable of dramatically changing geometry in flight to perform a range of missions effectively. Concepts include "virtual" control surfaces that disappear when not required to enhance stealth; fuselages that constrict as fuel is consumed; continuous control surfaces; and adaptive inlets that alter to suit flight speed.
HyperComp will work with NexGen Aeronautics to model morphing wing designs to see how variations in wing area, aspect ratio, sweep, twist and dihedral can be optimised to provide the best shape-shifting combination.
Lockheed Martin will work with the Air Force Research Laboratory (AFRL) at Wright-Patterson AFB, Ohio, until November 2006 to "develop and demonstrate technologies for a seamless, aerodynamically efficient, aerial vehicle capable of radical shape change". The contracts are the latest in a series of US morphing studies by AFRL's Air Vehicle Directorate, the US Defense Advanced Research Projects Agency (DARPA) and NASA. The AFRL's continuous moldline technology (CMT) programme evaluated elastomeric matrix materials reinforced with stiffening rods that could slide within the matrix to achieve high deformations. Recent tests on CMT structures showed the capability to stretch and shrink by 30% as well as bend and twist.
NASA's studies have mainly looked at the bending and stretching qualities of resin transfer moldings, piezoelectrics (which contract or expand on application of electric current) and shape memory alloys that change shape with thermoelectric input. The aim is to develop a design with an 8% increase in rolling moment using wing twist, a 10% increase in rolling moment using a hingeless aileron and an 8% increase in lift using a hingeless flap.
Targets for DARPA's morphing project, which is focused on developing Mach 0.5-0.9 wing designs for windtunnel tests, include a 200% change in aspect ratio, 50% change in wing area, 50% change in wing twist and up to a 28% change in sweep angle.
Source: Flight International
