REFLECTOR:Vortex Generators on XL

[Jim Sower]

Keith,
On the wing, I measured the chord at root (strake mating seam) and near the tip,
computed and marked the 20% chord and popped a chalk line for reference.  I marked off
points along that line at 6" or 7" intervals, fashioned a template from construction
paper that would lay along the chalk line with a hole to locate the point and a guide
to place a pair of VGs splayed 10-15 deg each side of the direction of air flow (same
on the canard, but template for straight v. swept reference line).

VGs came from Home Depot or Lowe's.  Got 8' of plastic weather stripping for about
$1.78.  It comes as an asymmetric channel with one side 3/8" wall, one 1/4" wall and a
1/8" bottom.  I cut off the 3/8" wall (except if I needed an oversize VG for
something), cut 1" segments off the strip and voila' - 96 perfectly serviceable VGs.
The first set (which I intuitively put at 25%) I snipped the vertical member wedge
shaped.  The second, after I got straightened out at Rough River I just trimmed the
points off the corners.  Mounted them with white silicone RTV (which is readily
available at my house) let it cure overnight and went flying.  The whole operation
took the wife and I a couple of hours - me cutting, her installing.  On the second set
I fashioned a jig to make the removal of the superfluous wall quicker and more precise
and it went somewhat faster.  Wife informs me that we have 14 pairs on each wing and
10 pairs on each side of the canard.

Whoever thinks the dollar a pop someone was paying is too steep, I'll be glad to
provide all you want for HALF that :o)

Hope this helps .... Jim S.

KeithHallsten wrote:

> Jim,
>
> 20% chord is pretty clear on the canard, but since the wing is tapered the
> chord is different at every station along the wing.  Did you place the VGs
> at an ever-decreasing distance from the leading edge as you move outboard on
> the wing to maintain true 20% chord at each VG location, or use 20% of an
> average chord for the group of VGs on the wing?
>
> Where are you getting rectangular VG's for $0.02 each?
>
> Keith
>