Among the eye-catching exhibits at IMTS 2014 in Chicago earlier this month were new military drones that can fly at speeds in excess of Mach 1 and at altitudes above 45,000 feet.
Wars often propel new plastics technology. Two examples are lightweight cockpit glazing in World War II and composite armor for ground vehicles in the Iraq War. Now as the
emphasis shifts to an aerial war on terrorists in the Mideast, the action will focus in part on unmanned aerial vehicles, or drones.
Several General Atomics MQ-1 Predators have been sent to Iraq to combat advances by the Islamic State of Iraq and the Levant. You can bet that manufacturing of drones in the United States is really ramping up right now.
From a materials’ technology perspective, drones are fascinating because they are a showcase for the latest in carbon reinforcements, polymer matrixes and 3D printing. Use of carbon composites and 3D printing has been slow to catch on in mainstream manufacturing because of cost and processing speed issues. But they play perfectly in the world of drones where higher costs and slower manufacturing speeds are not limitations.
The price tag on just one Northrop Grumman RQ-4 Global Hawk, for example, is now above $223 million.
Carbon composites are very strong, lightweight, and work well with geometries that have large, sweeping curved surfaces. Composites are used in airframe components, structural members and wing coverings. According to Solid Concepts, selective laser sintering (SLS) is used for small fuel tanks used in drones that often require intricate design features. Polyamide-11 plastics are preferred because they possess low porosity.
Kevlar/epoxy composites are often used to make propellers.