Novel Laser-Based Method Effectively De-Ices Aircraft | Hacker News Reader

Novel Laser-Based Method Effectively De-Ices Aircraft

optics.org

84 pointsrajnathani44 comments

Sadly it appears this is not a giant laser that shoots the plane when it's covered with ice. It's a way to change the surface of the wings so that ice/snow doesn't stick in the first place.

Yeah, I was expecting to read about how to get a gigantic laser out onto the runways. Still cool, though.

Right - this is anti-icing; not deicing.

Austin Powers 4:

Scott, I asked you for an airplane with frickin' lasers on it, and you give me a plane covered with what? What is this guys? It's sandpaper. You covered a plane in sandpaper. Do I have to do everything around here myself?

What? Wha wha? Are you gonna cry? Does Scotty wanna cry?

Indeed. I feel like I read about these micro-structures creating hydrophobic surfaces YEARS ago. Perhaps they just found a way to efficiently create them?

What happens when they paint the parts to prevent corrosion? I imagine all the properties of the laser etching are negated.

I imagine this technique would be most useful on the leading edge of wings and the engine nose cowlings.

On many aircraft those parts are left unpainted anyways.

> On many aircraft those parts are left unpainted anyways.

Erosion will de-paint it anyway.

As far as I understand it, corrosion isn’t that much of a worry with aluminum airframes— as long as the plane doesn’t spend too much time near salt water.

There are many past and present airline liveries where the fuselage is left largely bare, for instance:

https://upload.wikimedia.org/wikipedia/commons/5/5f/Boeing_7...

To the person who downvoted the above without leaving a comment:

Is this not the case? I know for a fact that planes whose home airport is near the ocean have more issues with corrosion.

If I'm wrong, I'd be genuinely delighted to learn how.

didnt downvote you but your link is broken (lost 'g' at the end)

Whoops! Fixed, thanks.

So everyone knows that aluminum develops a chemically stable oxidation layer that prevents ionization, or something like that.

In reality though, that layer shows zero mechanical strength. You don’t see that with aluminum products but only because they are always anodized. Without anodization or just left in the wild, aluminum develops white salt like corrosion on its skin.

I have anecdotal experience of this with a PowerMac G5. It was a school computer, I got to see inside, and years later I found fingerprints of my younger self permanently engraved on it.

That layer also doesn't shine, something people don't take into account. A local FBO with a fleet of gorgeous airframes polishes them at a minimum of monthly, and they don't fly more than about once a month.

Polished aluminum is labor-intensive to keep looking good. But I'm glad so many still take the time to do so.

Just because it looks bare doesn't mean it's unfinished.

If I specified sheet aluminum for Type II Class 3 chemical conversion per MIL-DTL-5541, any materials QC professional would be hard pressed to visually determine that anything was actually done to the material.

To be sure, no, MIL-DTL-5541 isn't an uncommon spec constrained to military applications.

any idea what they use on aircraft skins?

That's not an application you can generalize. Literally everything is dependent on requirements.

I know I've noticed on airplanes before that while some of the wing is aluminum colored, some areas in particular are painted a vaguely aluminum-colored shade of grey.

And I think the... it seems they're called Krueger flaps? Those are often painted aren't they? And those I'd think you'd definitely want to de-ice.

On an aircraft that has a mixture of polished and painted surfaces, the painted surfaces often aren't bare aluminum. Often that's the wing root fairings, winglets, nacelles, radar cones, vertical stabilizer, and so on.

I don’t think I was meant to get a giggle out of this. Can you explain using other words? Of course a painted surface isn’t bare. It’s got paint on it.

Did you mean it’s not aluminum? Or a different grade?

Thanks, I laughed at it myself, in hindsight. I should have stipulated "underneath" and likely appended an "if you follow...".

Yes, well, they may either be materials that have other surface textures/coatings/treatments/finishes that aren't conducive to polishing, or they may be other metals, or non-metallic composites (can't put aluminum over a radar, for example), and so on.

TL;DR: The painted surfaces are generally instances in which polished aluminum won't really work, for a variety of reasons.

In addition to that, behind every beautiful, polished aluminum aircraft is a crew that is washing, cleaning, and polishing it regularly. Polished surfaces are higher maintenance than painted ones, generally speaking, and by quite a bit.

Polished aluminum is not low maintenance by any stretch.

> corrosion isn’t that much of a worry with aluminum airframes

The internal aluminum components are all finished with BMS 10-11 Type 2 primer (the ubiquitous green stuff). (Amazing what trivia I remember from 40 years ago!)

If you don't paint it, you have to polish it periodically, which is more expensive. A pre-pitted surface probably more so.

Planes that are freshly painted are 'slick' -- they have noticeably less drag! A good paint coating also makes it easier to wash dirt and other contaminants, which cause drag and corrosion.

Corrosion is indeed a problem, but only severely for salty places.

Paints also have UV screen for plastic composite components.

I'm betting this becomes a paint job option. While it looks appealing I also can't help but suspect real world will just fill those crevices up with bug guts pretty quick.

Maybe it could be combined with this technique so the aircraft body can be laser-etched for both colour and anti-icing: https://www.rochester.edu/news/show.php?id=3106

Interesting approach and hugely useful if practical, though it bears mentioning that the leading edges on aircraft experience a fair amount of abrasion from dust, debris, and insects. I wonder how long this treatment would be effective for in a real world environment

Super important question, first thing that came to mind. How would you even test it for efficacy? Just look for ice building up and say 'welp, time for refinish?'

There are wind tunnels for testing icing behaviors, not too hard to do an accelerated aging test and come up with standard procedures.

Could be easier said than done. There are lots of edge cases that could become a problem in real use. Stuff like surface contamination from various fluids or environmental factors.

Do 90% of your testing in the wind tunnel, and sanity check your results by flying it for real.

Also the feature size is in μm range, so I imagine a flashlight or barcode gun shaped UV camera device to observe interference or reflectivity would be possible.

Turn off wing anti-ice, fly around, if you get ice buildup you turn anti-ice back on?

Having anti-ice on decreases performance and increases fuel use. So being able to fly without anti-ice on for longer is better.

Would be nice to save weight on full size anti ice systems. Flying around to test anti icing is also not the greatest approach. If ice starts to build up and you shed it, it can come off in chunks and break things.

the paper does mentions that; and honestly i'm interested in how long this sort of micropatterning lasts when it's incorporated in an aircraft, as well as how its anti-ice performance is affected as it gets fouled/abraded:

> Further research is required to understand the influence of different icing parameters on ice adhesion and to assess the compatibility and robustness of such surfaces in operational environment (i.e., rain and sand erosion, UV resistance, interaction with other fluids, such as hydraulic and anti‐icing)

Right. The press release claims it's being used on some Airbus 350, but that may just mean "we treated a small part of the wing so we can see what happens".

Fragility is a big problem with most of these microsurface treatments. There's the "Never Wet" treatment you can buy now; it's a two-component paint that hardens into tiny points to which water cannot adhere. Works great when new, wears out easily. It has to be the top surface or it won't work, so there's no way to protect it.

Same for that "ultra black" material. OK for camera interiors and other protected optical systems, too fragile to expose.

Amusingly, a common laser process for steel does exactly the opposite of this anti-icing process. The idea is to roughen the surface for painting, but in a regular way. Same effect as sandblasting, but because the pattern is regular, you get a smoother paint surface and don't have to sand the primer layer. Used in auto manufacturing.

Leading edges might be better served with deicing boots rather than special paint to constantly wear off. Or, if there were some abrasion-resistant film that is transparent to the laser light, then it might work.

I would think 3+ lasers would be needed to cover all aerodynamic surfaces.

If it can be manufactured for reasonable cost, effectiveness and sensible power consumption, seems like a fit for small aircraft, fighter jets and any aircraft that don't have deicing boots or anti-ice systems.

Anyone with a better background, are micro surface features required for this kind of thing or could teflon/rain-x type chemical coatings create a more durable/corrosion resistant/easily repairable effect?

Did Fraunhofer just repurpose MP3 codecs to aluminium surface patterns?

Very clever.

Also seems like something pulled from ancient aliens.

I was thinking Tony Stark. "How did you solve the icing problem?"

Nice. I'd drummed up Dr Evil, "Mr. Powers, you'll notice that all the sharks (planes) have laser beams attached to their heads. I figure every creature deserves a warm meal."

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