hydrophobic coating as anti-ice

[Piloto]

On ‎12‎/‎24‎/‎2016 at 10:53 PM, Jerry 5TJ said:

Second trial:. Today descending into Cleveland with the TKS on max I did pick up ice, maybe 1/4" on the lenses in about 3 minutes.    I had sprayed WD40 on the left lens before takeoff, about 2 hours before ice encounter.  Some light rain on departure.  Result--no difference seen left to right.  

IMG_0252.MOV

Like TKS fluid WD40 would need to be re sprayed to be effective. It appears that WD 40 is unable to stick to the surface under a 150kts wind. Thanks for the test, very informative.

José 

[goncaloareia]

On 12/25/2016 at 3:53 AM, Jerry 5TJ said:

Second trial:. Today descending into Cleveland with the TKS on max I did pick up ice, maybe 1/4" on the lenses in about 3 minutes.    I had sprayed WD40 on the left lens before takeoff, about 2 hours before ice encounter.  Some light rain on departure.  Result--no difference seen left to right.  

IMG_0252.MOV

Thanks A LOT for the this additional test!

Safe flights!

Goncalo

[Andy95W]

5 hours ago, goncaloareia said:

Thanks A LOT for the this additional test!

Safe flights!

Second that.

Wonder if anyone could also do a test of RainX or IceX?

Thanks in advance,

[Hedge]

On 12/26/2016 at 1:06 PM, Andy95W said:

Second that.

Wonder if anyone could also do a test of RainX or IceX?

Thanks in advance,

Rain X will eat through your paint.  It won't just discolor it.  But some type of hydrophobic coating would be the best solution.

[Andy95W]

12 hours ago, Hedge said:

Rain X will eat through your paint.  It won't just discolor it.  But some type of hydrophobic coating would be the best solution.

Glad you posted this before I tried it!

[Brandontwalker]

I use a Meguires spray wax after nearly every flight to clean off bugs and whatever else. It has a hydrophobic element to it and water sheets off the plane (wish I could use it on the wind screen). I would never think of this as an anti-icing measure, but it sure keeps the plane clean and shiny.

Meguiar's G17516 Ultimate Quik Wax https://www.amazon.com/dp/B001O7PNS2/ref=cm_sw_r_cp_api_c04EybWHKGDT9


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[aviatoreb]

I'm tempted to try some of these modern hydrophobic coatings on the bottom of a pair of cross country skis.

[carusoam]

Try as much as you want...  their staying power isn't very good.  The usual UHMW-HDPE has some pretty good slip characteristics on its own.  Wax selection improved on it by adding some temperature related benefits...

How long does a good wax stay on the XC skis?

On my slalom skis, a wax coating wouldn't last but a few runs.  Noticeable only by amount of slide on slight decline...

 

Simlar issue with the coatings on the windshield, it gets rubbed off pretty well by the windshield wipers.  The coating itself gets dirty over time...  rainX was always on my windshield.  It is dissapointing when the coating gets old and you have to use the wipers.  There is no getting better until the coating gets refreshed...  

Best regards,

-a-

[Piloto]

It looks to me that any liquid you spray on (including TKS) will not last too long under a 150kts wind. What is really needed is an anti-ice surface. I found that many ice cube trays are made of silicon to keep the ice from sticking on. Wonder if a silicon adhesive tape 3 inch wide adhered to the leading edge will do the trick. Has anyone here tried this?

José

[Guitarmaster]

It looks to me that any liquid you spray on (including TKS) will not last too long under a 150kts wind. What is really needed is an anti-ice surface. I found that many ice cube trays are made of silicon to keep the ice from sticking on. Wonder if a silicon adhesive tape 3 inch wide adhered to the leading edge will do the trick. Has anyone here tried this?
José

I thought I read Boeing is experimenting with this very thing.


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[Browncbr1]

I just spent an hour talking to one of the world's leading fluorine chemists...  wow i got a major, longer than expected chemistry lesson.

Basically, what we are trying to accomplish can't be done chemically without mechanical means of application.   There are molecular structural reasons in ice at low temps that cause ice to attach to surfaces mechanically.      He said a mechanically bonded teflon similar to a frying pan would be needed for a chance at inhibiting this mechanical bond.  Teflon on frying pans are applied by physically pressing teflon powder to the aluminum with big time pressure to cause a mechanical bond.  It cannot be sprayed on...   This means the surface is also brittle if bent, vibrated or if abrasives hitting it.   I bet this had already been experimented on aluminum props, but either didn't make it anywhere due to short longevity of the coating or it caused some other problems because on the very small scale, this kind of teflon looks like rime at the surface.   who knows...  

He said what we are looking for probably can't be achieved in fluorine or other chemistry. 

I'm going to shelf thinking about this anymore since by brain just exploded.

[John Myers]

Has anyone tried any of these?

Marketed for propellers: http://www.oregonaircraftdesign.com/iceaway.html

Many applications: http://www.neverwet.com/applications/anti-icing.php

Marketed for boots: http://www.sportys.com/pilotshop/bf-goodrich-ice-x-ii-16oz-spray-bottle.html

John

[aviatoreb]

On 1/16/2017 at 11:02 AM, Browncbr1 said:

I just spent an hour talking to one of the world's leading fluorine chemists...  wow i got a major, longer than expected chemistry lesson.

Basically, what we are trying to accomplish can't be done chemically without mechanical means of application.   There are molecular structural reasons in ice at low temps that cause ice to attach to surfaces mechanically.      He said a mechanically bonded teflon similar to a frying pan would be needed for a chance at inhibiting this mechanical bond.  Teflon on frying pans are applied by physically pressing teflon powder to the aluminum with big time pressure to cause a mechanical bond.  It cannot be sprayed on...   This means the surface is also brittle if bent, vibrated or if abrasives hitting it.   I bet this had already been experimented on aluminum props, but either didn't make it anywhere due to short longevity of the coating or it caused some other problems because on the very small scale, this kind of teflon looks like rime at the surface.   who knows...  

He said what we are looking for probably can't be achieved in fluorine or other chemistry. 

I'm going to shelf thinking about this anymore since by brain just exploded.

Interesting - flourcarbon is popular in the most expensive "race waxes" in cross country skiing and the appllcation procedures are arduous and require a lot of elbow grease.  But the stuff is amazing.

[carusoam]

How long it stays adhered to the surface will be important.  In slalom skiing with HDPE bases, a few aggressive runs down the slope is all it lasted...

Snow and ice are a bit more abrasive than air and water...

But speeds of 200mph are pretty aggressive compared to 30mph on snow...

Best regards,

-a-

Edited May 22, 2017 by carusoam

[jaylw314]

How about this?

http://advances.sciencemag.org/content/2/3/e1501496.full

The basic idea is instead of designing fancy superhydrophobic coatings, they found coatings that were rubbery and flexible were candidates for ice-resistant coatings.  Instead of preventing ice from accumulating, flexible coatings will deform at very low shear pressures, allowing the ice to shed.

So maybe spraying the wing leading edges with truck bed liner?  

[carusoam]

Consider what happens with air pressure against it...  does it compress and stay that way or does it vibrate?

does it's Compression alter air flow?  If it vibrates does it warm up?

Rubber boots have been used by many non-laminar wings. They seem to work pretty well.

Too many questions for me.

Best regards,

-a-

[L. Trotter]

On 1/16/2017 at 1:02 PM, Browncbr1 said:

I just spent an hour talking to one of the world's leading fluorine chemists...  wow i got a major, longer than expected chemistry lesson.

Basically, what we are trying to accomplish can't be done chemically without mechanical means of application.   There are molecular structural reasons in ice at low temps that cause ice to attach to surfaces mechanically.      He said a mechanically bonded teflon similar to a frying pan would be needed for a chance at inhibiting this mechanical bond.  Teflon on frying pans are applied by physically pressing teflon powder to the aluminum with big time pressure to cause a mechanical bond.  It cannot be sprayed on...   This means the surface is also brittle if bent, vibrated or if abrasives hitting it.   I bet this had already been experimented on aluminum props, but either didn't make it anywhere due to short longevity of the coating or it caused some other problems because on the very small scale, this kind of teflon looks like rime at the surface.   who knows...  

He said what we are looking for probably can't be achieved in fluorine or other chemistry. 

I'm going to shelf thinking about this anymore since by brain just exploded.

 This may be a little premature but I'll throw a bone out to chew on. 

There are new metallic alloys being patented that actually have utility now that we are able to harness laser energy.  The  coefficient of fiction is magnitudes lower than that of Teflon.  So much lower that  Industry standard equipment cannot measure the "slipperiness".   The laser cladded coating does not wear off and nothing  seems to sticks to it.  This new science has  seemingly unlimited  potential.  Most of the research to date has been done on coating  parts that we wear out in the manufacturing  Industry .  Once coated, they don't wear out any longer.  It is truly revolutionary.   At first we thought that lubrication would still be needed but could not get anything to adhere to the new surface.  A variety of different fluids would just bead up and rolloff.  An unexpected property of the new alloys.  What does this have to do with aviation, and this topic …  among other things you all have given me an idea of an anti-ice metallic surface.  Something similar to a Teflon coating.   I will send this to the lab with the idea of spraying supercooled  water droplets on a cold metallic alloys surface  to see if the water droplets stick. I'll worry about the paint issues later. 

[Mooneymite]

Many Bizjets use a windshield coating instead of  wipers to provide visibility in rain.  This coating lasts quite awhile depending on how often the jet flies in rain....in some cases, years, so it has a pretty amazing bond.

The interesting thing is that it doesn't make much (any?) difference in ice accretion rates.  The unheated portions of the windshield accumulate ice at about the same rate as other unprotected surfaces despite the coating.

[John Myers]

The above products seem to work on a different philosophy than TKS/glycol-, rather than lowering the melting point of water like TKS fluid, they let it freeze, but don't let it stick. This seems to work for at least some of those products, so then the question is back to "does it stick well enough to last a flight". I would love to see a test of one of the products that purport to do just this, it could really add to the safety margin in the winter, even for unprotected areas on planes that already have TKS.

John