The ThermaWing ice protection system uses a flexible, electrically conductive, graphite foil attached to a wing's leading edge. Once activated the parting strip has an instant temperature rise, first melting the ice, then shedding the ice due to aerodynamic force.
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Supported by the NASA SBIR (Small Business Innovative Research) program Kelly Aerospace Thermal Systems began production of the Thermawing ice protection system. In 1998 NASA Glenn initiated the research and development of the Thermawing ice protection system, capable of meeting all aspects of ice protection for the general aviation fleet. Product integration and certification of high output alternators, DC powered air conditioning, and thermoelectric de-icing are all derivatives of the NASA spin-off program. The current FAA certified heater element configuration was the result of extensive heater development, electronic control system design, and wind tunnel and flight testing.[1]
The original launch of the system was Columbia Aircraft Manufacturing (now Cessna) which utilizes a high performance, state-of-the-art composite airframe which offered unique design challenges. On the Cessna 350 and 400, The ThermaWing system (formerly EVADE) utilizes 6 heaters, 3 heater control modules, one main electronic controller, and one 7500 watt alternator to deice the aircraft.
The outer layer of the laminate is a heat-conducting Tedlar a very thin ice phobic. It offers a unique balance of aesthetics while offering the durability of a fluoropolymer. A zoned heater system is utilized and controlled by a solid-state processor. The impingement area, or leading edge, is kept warm continually melting impinging ice, or simply, "runs wet". The area just aft of this impingement area, or shedding zone, is kept below freezing causing the run back to freeze and collect as ice. During a de-ice cycle the voltage is increased raising the temperature of this aft shedding zone, releasing the ice bond and shedding the ice via aerodynamic force. Once power is removed from the heater the shedding zones immediately freeze and continue to collect ice until the next de-ice cycle. This system may take as little as 1 second per surface and only 33 seconds to deice the entire aircraft using a 60 second cycle.
Once armed, the system is digitally controlled with automatic shedding cycles activating at 41°F.