"new" surface treatment

[rb1957]

saw this in flight today ...

http://www.flightglobal.com/news/articles/aircraft-paint-suppliers-explore-sharkskin-coating-381646/

immediately it reminded me that sailing dinghys have known for a long time that really smooth, highly waxed, and glossy surfaces aren't the best ... a light scuffing improves the adhesion of the boundary layer.

immediately followed by ... and how is that relevent to airplane wings ? (surely the reynolds number is completely different ??)

and ... i wonder how this'll hold up in the real world (with dirt and insects getting into those tiny crevices) ?

makes me think of all the "optimisation" studies that go on ... how United (?) stripped the paint of their planes (to save weight) only to put it back when maintenance of the polished skins was more expensive than the fuel saved ... i think these things are lead by organisation changes, followed by the imperative for the new guy to "mark" his domain.

 

[btrueblood]

Riblets have been around awhile - 3M had a riblet "tape" under development. Yes, dust and impact damage will probably negate any advantage pretty quickly - but aren't there some new coating materials that have "self cleaning" properties in development?

Oh, and thought the Re_L for a dinghy was about the same as for a jet aircraft wing - factor of 100 difference in viscosity but a factor of 100 difference in speed also, net result is a similar Reynolds no.

 

[btrueblood]

3M had a riblet "tape" under development should've been: ...in the 1980's.

 

[Higgler]

Bad for Aircraft RCS

Any clue at what speed this becomes useful? Not mentioned in the article. I assume that answer is based on rib size.