REFLECTOR:Vortex Generators on XL

[Chuck Jensen]

Allegedly, not that you'd notice, at least according to some testing and
anecdotal evidence.  If you look at some of those cross-sectional contours
of air flow and pressures over a wing, it certainly looks like at cruise the
air bumps into the wing, then goes up and over, hence the flow across the VG
is minimal.  At lower speed, the airflow adheres to wing, thus more of the
flow is across the VGs.  The resulting turbulent flow adheres better to the
wing then laminar flow, thus lowering the stall point.

That is the pedestrian explanation.  Some of our AeroEngineers (or somebody
that knows what they're talking about) may offer a better, more accurate
explanation that is actually factual.

Chuck Jensen

-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of John Dibble
Sent: Tuesday, December 02, 2003 10:52 AM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:Vortex Generators on XL


Do vg's affect cruise speed?

John

Chuck Jensen wrote:

>Jack,
>
>Everything I do is trial and error.....though I did use the patterns
>provided by Velocity.  They are installed on both the canard and wing (and
>both sides, naturally).  I don't remember the exact count but buy a 100
>(they're cheap) and use the extra for replacements.  To paint them, after
>scuffing the bottom on sandpaper, I just stuck them on packing tape and
gave
>a few light coats of enamel for UV protection.
>
>Do us a favor.  Before you install, do a few altitude stalls and see if you
>can nail a number.  After installation, repeat and see what difference, if
>any, you note.  Maybe you already have a hard number for touchdown IAS that
>you can reference---that would make a before/after comparison even simpler.
>Most seem to think it reduces touchdown by 5 to 7 kts.
>
>Chuck Jensen
>
>  
>


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