REFLECTOR: Anti-Ice

[Chuck Harbert]

Larry, I thot I posted some comments about flying with ice about a month 
ago. I didn't keep a copy, so I'll say it again. A V test pilot (lots of V 
hours) told me that he had collected a fair amount of ice (over 1/2") on the 
canard and it not only slowed the plane, but also the plane began a pitch 
buck oscillation which he felt was caused by the canard stalling. He was 
very concerned about loss of control and now avoids any potential for icing. 
He talked with the factory about it a couple years ago.

I went to the website for Ice Engineering (watched the wing video) and then 
went to an article at the Dartmouth Engr website 
http://engineering.dartmouth.edu/thayer/research/ice-engg.html (copy below) 
which talks about the technology and the Goodrich tests. This looks very 
promising for light planes, and particularly for V's conditions. It'll 
probably be expensive now that Goodrich has the rights, but might be worth 
it if you plan to fly in possible icing conditions. Hopefully, it will be 
available in a couple years.

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Petrenko's PETD uses a thin, electrically-conductive film applied to the 
surface of, for example, an airplane or a windshield or almost any other 
object in need of ice protection. The film is then heated with a 
milliseconds-long pulse of electricity. The beauty of this method is that 
only a micrometer-thin layer of ice directly at the ice-material interface 
is heated without having to heat the bulk of the object to which the ice is 
stuck. Even in extreme cold, PETD achieves nearly perfect efficiency because 
neither the object nor the air is heated-the heat simply does not have time 
to propagate into the environment. Just one single pulse of electricity 
melts the interfacial ice and instantly releases any additional build-up, 
which then easily slides off. Regular electric pulsing can keep surfaces 
consistently ice-free while maintaining low overall power consumption.



      » Aerofoil de-icing (1.5MB)
      » Panel de-icing (1.5MB)
      » Power line de-icing (1.3MB)
      » Windshield de-icing (1.1MB)

      » Download QuickTime Player


The de-icing film can consist of either a transparent conductor (such as 
indium tin oxide) for window or lens applications, or of a more durable 
coating (such as titanium) when extra wear-resistance is needed. For 
protection of large surfaces, thin metal foil or carbon-fiber composites are 
most effective.

Almost no heat energy is lost or wasted in this process and this optimal 
energy-efficiency in melting ice from surfaces is what makes PETD 
energetically feasible for aerospace applications and automobile 
windshields. Resistive heaters, such as the heated wires on rear windows of 
cars, cannot melt ice from windshields or wings because strong convective 
heat loss prevents the wires from reaching ice-melting temperatures without 
unrealistically high power usage. Heat loss to the earth and air is the 
reason traditional heaters are impractical for de-icing roads, bridges, 
walkways, and roofs. But Petrenko's super-efficient PETD has demonstrated 
immediate effectiveness and saves up to 99% of electric energy compared to 
conventional heaters. Goodrich Aerospace has completed the first in-flight 
testing of PETD on a small prop-plane. The results were "outstanding," and 
the next phase of field testing will involve a jet aircraft.