High-Tech Electro-Defroster

DahBaker writes to mention a News.com story about an ingenious way to de-ice a surface. From the article: "Dartmouth College engineering professor Victor Petrenko, not to be confused with one of the Champions on Ice, has devised a way to use a burst of electricity to remove ice caked on walls or windows. For surfaces coated with a special film, the jolt gets rid of ice in less than a second, far less time than it takes to hack at it with an ice scraper. While drivers might find easy-cleaning windshields convenient, the technology--called thin-film pulse electrothermal de-icing, or PETD--could have significant economic impact if widely deployed. It could, for example, cut the costs of repairing power lines downed by ice storms and keep plane windshields frost-free, decreasing fuel consumption."

Comments

Not just plane windshields

[MadEE]

Assuming the material is durable enough it would be great on the flying surfaces too preventing icing which adds considerable weight and changes the aerodynamics of the plane. This would probably be far lighter then current solutions for this.

Re:Not just plane windshields

[Maxwell'sSilverLART]

Assuming the material is durable enough it would be great on the flying surfaces too preventing icing which adds considerable weight and changes the aerodynamics of the plane. This would probably be far lighter then current solutions for this.

Actually, this was my first thought too, but after reading the article, I'm not sure how much use it would be in aviation. As you correctly point out, the big problem with ice in aircraft isn't the windshield, but airframe icing (wings and tail); ice (or even frost) changes the shape of the airfoil, destroying the lifting capabilities of the surfaces.

With a small panel, like a windshield, the power problem is manageable, but the leading edge of an airliner's wing is several hundred square feet (even a relatively small 737 has a wingspan of over a hundred feet for the later models, and you need to go at least a foot or two back on both top and bottom). Even assuming we only work on the leading edge, that's a hell of a lot of surface, and thus a lot of power. In reality, jet aircraft use hot wings, heated by bleed air from the turbines, and they heat the water on the leading edges enough that it stays liquid all the way to the trailing edge--these systems are more correctly called "anti-icing" than "de-icing."

Smaller aircraft do use de-icing systems, in the form of pneumatic boots. With such systems, ice is allowed to accumulate until it reaches sufficient thickness to be thoroughly broken by inflating the boots, causing it to crack and fall off (deploying the boots early can result in the ice simply forming around the shape of the inflated boots, rather than their deflated shape, rendering the boots ineffective). I'd be interested to see whether this system suffers from a similar problem, or if it is effective against even trace buildups.

The problem with it in light aircraft, though, is that such aircraft tend to have very low power budgets--there's not much surplus energy around. If there were, they'd use anti-icing systems, but intermittently shedding accumulated ice is very energy-efficient, especially when compared to energetic ice prevention (some aircraft carry alcohol anti-icing solution, which is excreted through "weeping wings" to forestall ice formation, but such systems are limited in the protection they can offer, both in severity and duration of icing conditions). Thermal anti-icing is cost-prohibitive, and electrical systems in light aircraft tend to be adequate, but with little overhead--while this system is more efficient than (presumably electrical) heating, it still may not be efficient enough. I'd also be interested to see what kind of electrical and magnetic noise this system might generate, though I'm sure that's been considered.

All in all, this sounds like a neat idea, but I'm not sure it's going to find its market in aviation.

Re:Not just plane windshields

[darthwader]

(deploying the boots early can result in the ice simply forming around the shape of the inflated boots, rather than their deflated shape, rendering the boots ineffective.)

I really hope that no pilots are getting their flying advice from slashdot (just like no lawyers are getting legal advice here), but just in case: the latest research indicates that ice bridging is a myth, and you should use the boots as soon as you detect any icing, rather than waiting for build-up.

http://www.aopa.org/pilot/features/inflight9910.ht ml, http://www.elliottaviation.com/wavelink/1999q1/wav art21.asp and http://www.faa.gov/library/manuals/examiners_inspe ctors/8400/fsat/media/fsat9818.doc are good references.

http://www.pilotfriend.com/safe/safety/icing_condi tions.htm is a great article about all sorts of aircraft de-icing and anti-icing methods.

Re:Is it me..

[MyLongNickName]

Everyone was out on a hot date, or getting ready for the celebration of Christ's resurection. This is Slashdot after all.