NACA ducts: where to buy?

[sssgtr]

After a NACA duct for an intake to feed a custom air box, i've found a suitable one on chassisshop.com but they want $85 USD to ship a $25 USD part via UPS.

the ones one ssv.com.au don't look like the recessed type, and all the others are the type that allows a 3" hose to be attached, these look like they will protrude too far down.

Anyone know anywhere else to buy these from?

[Nero]

don't bother, the majority of them are junk and only look like a naca duct.

[sssgtr]

Yeah i realize the ones from ssv and the like are crap, the ones available from www.evol-art.com look to be the goods, and they're in CF too.

ie:

[Nero]

these too are junk. The edges of a naca duct need to be sharp and the back edge needs to be well radiused for it to work as a naca duct...they are quite fussy things. However if you are wanting it to work a bit and just look like a naca duct then go for it.

[Billzilla]

Yeah i realize the ones from ssv and the like are crap, the ones available from www.evol-art.com look to be the goods, and they're in CF too.

ie:

Looking at that picture, no they're not good.
The curved edges of the ducting need to be sharp, not rounded, to make the vortex that helps suck the air into the inlet.
I'll see what I can find on some real specs for you. They're not too hard to build.

[Nero]

haha...I beat bill to an aero question!

[Billzilla]

haha...I beat bill to an aero question!

Nope, I accidentally hit EDIT instead of QUOTE a couple of posts above ...

[Billzilla]

http://naca.larc.nasa.gov/reports/19...a-acr-5i20.pdf

That's the best document I could find that goes right into the detail of them. Too much detail, really, but it'll tell you how to make them properly.
It makes a big difference as to how well they work.

[sssgtr]

Brilliant, thanks guys.
I've got some modelling foam that i can use to hand cut out the shape of the duct to make a mould and get the sharp edges at the flange that transition to the scoop, then lay it up in fibreglass or carbon.

[smee]

EVO IV has one on the bonnet.
An example in the forsales. Maybe able to source one from a Jap import wrecker or there abouts.