NASA Spinoff

Energy-Efficient Systems Eliminate Icing Danger for UAVs

One of the more remarkable developments in aviation in recent years has been the increasing deployment of unmanned aerial vehicles, or UAVs. Since the invention of the first UAV in 1916, these remotely—or sometimes autonomously—controlled vehicles have become invaluable tools for military reconnaissance and combat, cargo transport, search and rescue, scientific research, and wildfire monitoring. Free from having to accommodate the safety needs and endurance limits of a pilot, UAVs are capable of flying extended missions and venturing into hazardous and remote locations.

altThere is one common aviation danger, however, that plagues unmanned and manned aircraft alike. In certain atmospheric conditions, layers of ice can build up on an aircraft’s leading surfaces, dramatically affecting its aerodynamics and resulting in decreased performance or even complete loss of control. Lightweight UAVs are particularly susceptible to icing problems, and the potential damage icing conditions can cause to these expensive vehicles can render their operation unfeasible in certain weather. This is particularly troubling for military UAV applications, in which icing conditions can lead to aborted missions and the loss of crucial tactical capabilities.

Countering the threat of icing has been one of NASA’s main aeronautics goals. NASA research has led to a variety of deicing technologies that are now making aviation safer for all aircraft. One such solution, invented by Ames Research Center engineer Leonard Haslim, employs a pair of conductors embedded in a flexible material and bonded to the aircraft’s frame—on the leading edge of a wing, for example. A pulsing current of electricity sent through the conductors creates opposing magnetic fields, driving the conductors apart only a fraction of an inch but with the power to shatter any ice buildup on the airframe surface into harmless particles. Haslim called his invention an electroexpulsive separation system (EESS), or the “ice zapper,” and it earned him NASA’s “Inventor of the Year” award in 1988. Decades later, this technology is now proving to be an ideal solution to the UAV icing dilemma.

Partnership

Aeronautics engineer Mark Bridgeford was wandering through a technology trade show when he came across a booth where a pair of representatives from Ames was displaying NASA innovations, including something that attracted Bridgeford’s attention. The representatives were setting poker chips on a device and popping them into the air to demonstrate its capabilities; it was a model of Haslim’s invention. Bridgeford immediately realized that there was nothing like the EESS on the market and learned that Ames was actively seeking to transfer the technology to the public sector.

“I recognized from the beginning that this was a home-run technology,” Bridgeford says. In 1995, he and business partner Richard Olson formed Temecula, California-based Ice Management Systems (IMS, now known as IMS-ESS after merging with cable and harness assembly manufacturers Electro-Support Systems in 2007) and licensed the patent for Haslim’s innovation from Ames that same year.

Through the course of extensive research and development, IMS built upon the existing NASA concept, creating an energy-efficient power system and a composite, leading-edge cuff with the conductive actuators embedded internally in the carbon-fiber structure. The company conducted extensive testing in icing tunnels, including the Icing Research Tunnel at Glenn Research Center, proving the technology’s consistent effectiveness in removing ice from airframe surfaces.