Reverse NACA ducts

Reply Subscribe

Thread Tools

Search this Thread

06-10-2019, 01:58 PM

1RMDave

Junior Member

Thread Starter

Join Date: May 2018

Posts: 205

Total Cats: 23

Reverse NACA ducts

Hey, looking to do some hood venting. I found these NACA ducts on ebay https://www.ebay.com/itm/NACA-air-ve...8AAOSw-0xYPZJd they are aluminum and come off a Grumman Tiger airplane for under $30 each. Thoughts on using these backwards for hood vents? Here is some info on running them backwards:

06-10-2019, 02:20 PM

jpreston

Senior Member

iTrader: (4)

Join Date: Dec 2008

Location: KY

Posts: 940

Total Cats: 176

I remember seeing wind tunnel test results a few years ago for naca ducts mounted backwards. The conclusion was that the naca shape has no real benefit when mounted backwards, and a simpler vent shape is equally or more efficient. The naca shape really shines as an inlet.

It sounds like the nascar teams just did it because of a rules loophole. Wording like "no vents or holes may be placed in windows other than NACA ducts" with no specification for duct orientation. Their only options were backwards naca duct extractor or no extractor, and the backwards naca duct was the winner.

06-10-2019, 03:29 PM

ryansmoneypit

Elite Member

iTrader: (6)

Join Date: Feb 2013

Location: A cave in Va

Posts: 3,395

Total Cats: 456

i also found that they are not great when run backwards

06-11-2019, 06:29 PM

ThePass

Supporting Vendor

iTrader: (3)

Join Date: Jul 2006

Location: San Diego

Posts: 3,303

Total Cats: 1,216

^ What they said.

__________________

Ryan Passey

SingulärMotorsports Good-Win-Racing

06-12-2019, 01:32 PM

1RMDave

Junior Member

Thread Starter

Join Date: May 2018

Posts: 205

Total Cats: 23

Sounds good, thanks for the input! Gonna go with the 5 piece set of R Theory vents.

06-12-2019, 01:34 PM

matrussell122

Elite Member

iTrader: (1)

Join Date: Sep 2016

Location: Seattle

Posts: 1,859

Total Cats: 516

Quote:

Originally Posted by 1RMDave

Sounds good, thanks for the input! Gonna go with the 5 piece set of R Theory vents.

do the singular vents

06-12-2019, 01:40 PM

1RMDave

Junior Member

Thread Starter

Join Date: May 2018

Posts: 205

Total Cats: 23

Quote:

Originally Posted by matrussell122

do the singular vents

I do like the Singular vents with the gurney flaps however this is one of those rare instances that I get to support the Canadian economy and probably save a lot on shipping. I may add my own gurney flaps to the R Theorys.

06-12-2019, 01:46 PM

acedeuce802

Senior Member

iTrader: (1)

Join Date: Dec 2010

Location: Farmington Hills, MI

Posts: 1,218

Total Cats: 175

I thought R Theory's business was on hold?

06-12-2019, 03:47 PM

1RMDave

Junior Member

Thread Starter

Join Date: May 2018

Posts: 205

Total Cats: 23

Quote:

Originally Posted by acedeuce802

I thought R Theory's business was on hold?

Oh I dunno... Still taking orders on website...

06-12-2019, 05:32 PM

#10

1RMDave

Junior Member

Thread Starter

Join Date: May 2018

Posts: 205

Total Cats: 23

I sure hope I can get R theorys. Singulars will be $260usd

06-14-2019, 05:15 AM

#11

dc2696

Senior Member

iTrader: (2)

Join Date: May 2005

Location: Edmonton Ab, Canada

Posts: 1,202

Total Cats: 21

Quote:

Originally Posted by 1RMDave

I sure hope I can get R theorys. Singulars will be $260usd

Have the 5 piece R Theory on route out west, no issue with getting them ordered. Those singulars are just brutal after conversion and shipping :(

06-14-2019, 07:05 AM

#12

1RMDave

Junior Member

Thread Starter

Join Date: May 2018

Posts: 205

Total Cats: 23

Quote:

Originally Posted by dc2696

Have the 5 piece R Theory on route out west, no issue with getting them ordered. Those singulars are just brutal after conversion and shipping :(

Did you order them off the website?? How long ago did you order them? Thanks for chiming in, I'd still like to order the R Theory's! I can't believe some vendors want $65 usd to ship the Singular vents, that's almost $100cad and they ship flat so obviously no big box needed.