Is Matt Paint Faster than gloss!?

[greenpower dude reloaded]

Ok this may sound crazy to some of you at first but the other week I was talking to one of my old electric race team, team mates (down the pub) and it turns out he is now a proffessional kiteboarder.

After a catch up on about 5years we then discussed design of the new car and he was telling me how they now paint all of there boards in matt paint as it's tangibly faster.

The way he explained it was that the paint traps air and water so in the case of a kite board your essentially riding a bubble so that instead of board against water its air and water against water, and that is deffinatly lower resistance.

Now after hearing this im considering painting the new EV car in matt paint because aerodynamics and hydrodynamics both come under "fluid dynamics" which means they act the same, theres just a difference in viscosity and therefore resistance as far as I understand, although im sure there must be more to it than that.

So basically I was thinking that maybe it would build up a nice "bubble" shall we say to lower skin friction the only thing I am wondering is would it really work in air, maybe its the greater viscosity of water that allows it to work on a Kite board.

..And more specifically would it work at the speeds we travel, i'm aiming for around 45mph top end speed.

So come on then what do you all think??? The thing that I thought is howcome its not widely used in motorsport?? After doing a little bit more research and asking around it turns out that another ex-team mate now races yachts and he says that he wet and dry sand papers his hull below the waterline.

Anyway I look forward to hearing all of your opinions on this,

-Luke

[Giblet]

I know one team last year, I think it was Redbull/STR but I could be wrong, painted all the logos and stuff on the car instead of using stickers like all the other teams, just to reduce drag and turbulence. If you took all the decals on a car and stuck them together in a pile, it would likely be akin to strapping a 4 foot 2x4 on the car somewhere.

A hydrodynamic element in water that has a huge effect transferred to a car at the same size might do virtually nothing. This being said, the gains for matte paint might in air might be too small to offset other variables outside of aero.

One problem I see is the quest for tighter packaging over the last few years have given many teams a host of cooling problems. I feel matte paint will keep far too much light from bouncing off the car and being converted to nasty, evil heat.

Now for the physics prolem inherant in your question.

You know that a kiteboard goes faster in the water because the water is seperated from the paint by bubbles of air. In the air, if you propose the inverse to use water bubbles, the water will obviously dry out, and change the paint. This being said, you also can not seperate the paint from the air using air, as, um, there is not that seperation you're looking for.

This does make me wonder though, if you had a water mister at the nosecone of an F1 car, would the water passing over the car mixed with the air make the wings work better? Like a lot better? The water would likely evaporate almost instantly in the hot backwash of the car.

Maybe a quick mist to make a pass on the outside, or to outbrake your opponent.

Sounds like a Colin Chapman solution


Cheers.

[greenpower dude reloaded]

I was actually wondering whether the air would act the same way as the water does on the kite board. I probably didn't put that across very clearly was quite tired when I posted it, I really need to stop posting whilst sleepy!

But now that you mention it that is quite an interesting idea.

If I had enough time (and a wind tunnel) I would love to test all of these different ideas and compare them to traditional waxing and glossy finishes.

[Ciro Pabón]

There was this thread (The air wing) on how some animals, like sharks, have rough skins (or other tactics). Some members were interested by the air bubbles used in some torpedos. Some others pointed to the feasibility of altering the surface properties by micro-actuactors embedded in it. Other mentioned the fact that you could direct the air using electricity on the surface.

I don't think water mist is going to help, having greater density should increase drag.

On the other hand, thinking about that torpedo, what would be the net effect of a jet of air blowing on the surface, coming from a nosecone similar to this?



The drag induced in the skin should be compensated by the reaction of the air on the cone, cancelling somehow. Besides, and more important, the "surrounding air" should "see" a static layer on the surface (because the air is blowing backwards at the same speed of the car). Yes, I know it sounds like perpetual motion, but...



I don't think this idea hasn't been tested somehow by somebody, somewhere. Does it work or does not?

[greenpower dude reloaded]

Hang on, not sure I totally understand, so how exactly does it work? from a scientific point of view how does it create the static boundary layer??

How would you create the jet in the first place? its all really interesting. With it becoming more and more apparent every season in our series that aerodynamics is the key to success and the more different innovative ideas the better!!

Thanks everybody keep up the good work i'd still like to hear more!!!

[Carlos]

Ciro - Thanks for bringing up one of my obsessions. Directed stream Coanda effects - fertile ground for consideration

Lots of interesting ideas and applications that can be extended to car design here:
http://www.rexresearch.com/coanda/1coanda.htm
http://en.wikipedia.org/wiki/Coanda_effect

[tomislavp4]

I just found a PDF file on the circulation controll wing that uses the coanda effect, it´s worth reading I think http://www.ae.gatech.edu/people/lsankar ... thesis.pdf

[The FOZ]

I don't know the answer to the original question, however, I'm curious if any research has been done into dimpled surfacing, such as on a golf ball...

I know Atomic (the ski company) has been producing racing skis with dimpled topsheets (called Aerospeed and Aerospeed 2) for years now, and have claimed improvements...

[manchild]

I don't know the answer to the original question, however, I'm curious if any research has been done into dimpled surfacing, such as on a golf ball...

I know Atomic (the ski company) has been producing racing skis with dimpled topsheets (called Aerospeed and Aerospeed 2) for years now, and have claimed improvements...

Welcome to the forum.

Dimples have been already discussed in several threads so you can check it out

viewtopic.php?t=881&highlight=dimples
viewtopic.php?t=1104&highlight=dimples
viewtopic.php?t=414&highlight=dimples
viewtopic.php?t=671&highlight=dimples
viewtopic.php?f=6&t=3185&hilit=dimples