REFLECTOR: VG for naca scoop.

[Tony Babb]

That wasn't the article, although it was interesting.

 The one I was thinking of is in Velocity Views Volume 29, 1st Quarter 2002
Page 7 in the Factory News section. Basically they tried a couple of
approaches
1. Put a couple of VGs about 1 inch in front of the overhead NACA scoop
angled slightly outward toward the rear, they reported a 40 - 50f degree
drop in CHT. 
2. Put a couple of VGs in the throat of the NACA about 2 inches from the
front, also angled slightly outward toward the rear, these produced a 20f
degree drop in CHT.

They also put two VGs about 4 inches in front of the armpit scoops and
angled slightly outward toward the rear, they reported a 40f degree drop in
CHT.

Cheers,

Tony
SEFG, 62% done, 78% to go
www.alejandra.net/velocity 
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Brett Ferrell
Sent: Wednesday, March 19, 2008 10:28 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: VG for naca scoop.


Tony,

I think that this is the article that you're referring to.  I've been
seeking to expand my website with more content for owner/flyers as well as
builders, and since there were so many great articles in the views I
requested permission from Rick Lavoie to reprint some of them (to which he
graciously consented).  Here's the direct link:
http://n44vf.velocityxl.com/articles/views/VV_1Q2003_VG.pdf

Brett
www.velocityxl.com (old builder's site)
www.n44vf.com (new overall site)

>  -------Original Message-------
>  From: Tony Babb <tonybabb at alejandra.net>
>  Subject: Re: REFLECTOR: VG  for naca scoop.
>  Sent: 19 Mar '08 10:32
>  
>  There  was an article in Velocity Views a couple of years ago about 
> VGs on  the top NACA  scoops. Sorry I don't recall exactly what they 
> said.
>  
>  -----Original Message-----
>  FROM:   reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] ON
>  BEHALF OF   Al Gietzen
>  SENT: Wednesday, March 19, 2008 8:05 AM
>  TO:   'Velocity Aircraft Owners and Builders list'
>  SUBJECT: Re: REFLECTOR:   VG for naca scoop.
>  
>  
>  Can anyone tell me how far ahead   of the oil cooler scoop to place the
>  vgs to increase flow, also I want to put   some ahead of my cabin
>  ventilator on the bottom of the pan as I'm not getting   much flow out of
>  the vents in the back seat.
>  
>  
>  Any thoughts would be   appreciated.
>  
>  
>  \Thanks
>  
>  
>  Jim
>  
>  Jim;
>  
>  
>  I'm not the expert,   but I don't think it's a one
>  answer fits all.  It depends on where the   scoop is and how much
boundary
>  layer buildup is expected. It may have to be   trial and error.
>  
>  
>  If you are speaking   of the stock NACA inlet on the side near the nose,
I
>  wouldn't expect much   potential from VGs.  At that point there
>  isn't much BL, and relatively   high pressure on the diverging
>  surface.
>  
>  
>  As a general   answer, I'll just guess about 12" for small VGs
>  and shallow BL and further for   larger VGs and thicker BL. Maybe someone
>  else has some experience and   empirical data.
>  
>  
>  Al
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