| Abstract | In-flight and ground icing has historically posed a significant problem for all types of aircraft, and
has been determined to be the cause of numerous accidents. Canadian airspace is especially
hazardous as air temperatures are typically sub-zero, leading to ripe conditions for the onset of
icing. Ice accretion on the leading edge and other areas of wings, fuselage, windows, engine
inlets, and sensors degrade the aerodynamic form of the aircraft, and results in decreased lift and
a higher stall velocity. Multiple solutions to this problem have been developed and applied to
fixed-wing and, to a lesser extent, rotary aircraft. Most of these applications have shown promise
and some have already seen limited service time. However, all current applications have
considerable disadvantages, specifically in terms of weight and power requirements.
Rotorcraft are known to be particularly sensitive to in-flight icing due to the large effective
distance the rotor blades travel compared to the effective distance that any component of a fixedwing
aircraft travels. The lift generated by the rotor blades is extremely sensitive to the effective
shape of the blade itself; therefore, it is imperative that ice is either prevented from forming, or
effectively removed once formed.
The majority of today's civil and military helicopters certified to fly in icing conditions are
equipped with electro-thermal ice protection systems. Due to their proven record of reliability,
durability and effectiveness versus the complete spectrum of other de-icing technologies
developed, electro-thermal de-icing remains the favored solution after decades of research and
development. However, due to the weight and considerable power consumption demands of an
electro-thermal system, alternate anti- and de-icing methods have been intensely studied. This
paper summarizes the numerous anti-/de-icing methods that have been studied and/or applied to
rotorcraft to replace the electro-thermal systems and explores the feasibility of using shape
memory alloy actuated systems as a more efficient means of rotorcraft de-icing. |
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