Anti-ice

[Marc Zeitlin]

Yes, I read it. But I think you're missing the basic idea here. FUBAR's proposal is to put wires in the leading edge in order to HEAT it, in the same way that the rear window of your car is heated.

And my response to that was, "figure out how much power you'll need". We've got 60 Amp alternators in our aircraft - that's 720 Watts at 12V. That's barely enough to keep someone's feet warm INSIDE the plane if you use a 12V electric heater. Now you want to use that to melt ice along 35 feet of wing? Even if you think you only need to melt the first 6 inches (which I don't buy for a second), that's 17 square feet of ice that needs to be melted, with power that can barely raise AIR temperature by 20-30 degrees.

 

Not going to happen.

 

... And if it works like boots, you need to wait until you've got a fair bit of ice for it to work at all (inflating boots before the ice is thick and strong enough to crack won't shed it).

But it doesn't. According to the articles, it can be pulsed at any time, no matter what the ice thickness, and it will blow the ice off. Boots operate very slowly, so they can't do this.

 

...... Ice forms from the leading edge aft, so if you have a leading edge that's warm, no ice .....

Yes, nice in theory, impossible in practice, without a lot more heat than is available electrically (or probably even at ALL, from the engine in any manner). That was my point - that there's not enough electrical power to heat the wing/canard leading edges to a temperature that will keep ice from forming or to melt it, when the wing is traveling through freezing cold air at 100-200 mph.

[interestedbutconfuse]

Marc,

 

I just was reading an article about Boeings new 787, which will be the first virtually all electric airliner. This includes the wing deicing, which surprised me. Boeing expects the wing deicing to take 100kw for the 787. The wingspan is 170feet, but I couldn't find any more information about it, such as thickness, or how much of the wing is 'deiced'. I'm confident numbers you quoted for melting all the ice are correct, but I'm not sure you took into account that the entire ice load doesn't have to be melted - only the fraction that is actually adhering the ice to the wing. Potential prop damage from separated but unmelted ice would also have to be considered.

 

The goal is NOT to fly into known icing, merely save my butt if I inadvertently fly into unknown icing conditions.

 

I wonder how 100kw over a 170 foot wing at airline speeds (recognizing that most icing is probably encountered at lower altitudes & speeds than their max cruise) translates to a wing the size & speeds of the Cozy? Probably still way more than we can generate.

 

Mark

[sbarton]

This is fun. Sure its been hashed and rehashed by engineers for decades, but what the heck, I'll play.

 

what about using sound, resonation or other such foolishness to loosen the ice up so the airstream can finish the job.... fiberglass might be idealy suited to something like this.

 

remember those vibrating football games in the 70's?

 

noodle that for awhile and report back here with some possible implementations...

 

 

Bart

[sbarton]

Ceramic Piezoelectric transducers molded into the underside of the leading edges spaced appropriatley might be used to induce the necessary aggitation.

[ronan]

Anti ice would be nice.

 

Not that I think it would be useful on a Cozy, but I always wondered about use of exhaust heat for de-ice. I did a search and found this:

http://www.stormingmedia.us/30/3088/A308892.html

Seems like on a pusher, the prop should have some protection .

 

The AOPA has good article on icing here:

http://www.aopa.org/asf/publications/sa11.pdf

 

Ice phobic coatings are a REAL option. They are not as effective as other options, but may buy a precious minute for a 180degree turn.

http://www.amil.chicoutimi.qc.ca/amil/amil/publications/papers/Icephobic coatingsIWAIS2002.pdf

 

How about waxing your wings? Glider pilots know that this improves performance, and will make the surface a little more hydrophobic, hence, somewhat ice phobic.

I wonder if Rain-X would perform better than wax? And there is a link to some other stuff called RejeX and Toughseal as well. I have no experience with these.

 

Glider wax, various types available here:

http://www.wingsandwheels.com/page44.htm

and here (also a 'prop' ice inhibitor - could be used on wings?):

http://www.aircraftspruce.com/pdf/2007Individual/Cat07340.pdf

 

Rejex article here:

http://www.corrosionx.com/articles/AvConsumer4_03.pdf

Toughseal:

http://www.toughseal.com.sg/

 

Now I wouldn't dream of intentionally flying into icing conditions, but it wouldn't hurt to have smooth slippery wings in an accidental encounter.