REFLECTOR: VGs for engine cooling NACA scoops

[Andrew Ellzey]

Can you send me a copy, or better yet, can you share it with everyone on the reflector? Did Ken say that it would be different for the XL?

Andy Ellzey
XLRG
ajlz72756 at yahoo.com 



----- Original Message ----
From: Douglas Holub <douglas.holub at gmail.com>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Sent: Monday, March 9, 2009 9:38:15 PM
Subject: Re: REFLECTOR: VGs for engine cooling NACA scoops

Thanks to everyone for all the input. Ken Baker sent me a .pdf of a template. It shows 1.375" and 2.00" for my Standard fuselage. The angle measures about 19 degrees on each side of the airflow (for a total included angle of  38 degrees between the VGs.)

There's a great seminar from Oshkosh '07 about cooling Rutan type aircraft at http://www.ez.org/downloads.htm. If you listen to the .mp3 file while you watch the PowerPoint slides, it's almost like being there.

Doug Holub
N2980W, Standard FG

----- Original Message ----- From: "Tony Babb" <tonybabb at alejandra.net>
To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
Sent: Monday, March 09, 2009 4:29 PM
Subject: Re: REFLECTOR: VGs for engine cooling NACA scoops


> For those who have it, the Velocity Views article was in VV 1st quarter 2002
> - Volume 29, page 7. For those without here's a summary of the article:
> 
> If you already have armpit scoops consider adding VGs, The factory XLRG had
> a 40 degree reduction in CHT adding just VGs, about 4 inches in front of the
> armpit scoop entrance, the leading edge of the VGs are 1.5 inches apart, the
> trailing edge 2.25 inches apart - they didn't say how high the VGs were. For
> those with NACA scoops, they placed VGs about 1 inch in front of the NACA
> inlet, same angle as for the armpit scoop and reported 40 - 50 degree CHT
> reduction. They then tried putting VGs in the throat of the NACA inlet,
> about 2 inches from the front of the throat, reported 20 degree reduction in
> CHT. With a standard fuselage move the VGs closer together but leave the
> same difference in width - .75 inches to provide the correct angle.
> 
> Tony
> 
> 
> 
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Dave Philipsen
> Sent: Monday, March 09, 2009 8:20 AM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: VGs for engine cooling NACA scoops
> 
> 
> nmflyer1 at aol.com wrote:
>> I could use the NACA VG placement pattern as well.
>> 
>> Kurt
>> 
> Ditto for me.  I'm thinking about adding the NACA scoops this year and
> getting rid of the armpit scoops.
> 
> 
> Dave Philipsen
> Velocity STD FG
> N83DP
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