REFLECTOR:Vortex Generators on XL

[Scott]

Jim,

These are installed on an XL right?

How did you establish that you haven't messed up the lift ratio between the 
canard and the main wing?  Have you done stall testing in it since you 
installed the VG's in an aft limit CG loading?

If you've added more proportional lift capability to the canard than to the 
main wings you have set your self up for a deep stall scenario.  Though 
because the increased lift is generated by forward flow over the wings, I 
think it would drop right out of it.

The price of your VG's is certainly good,  they are UV resistant?  How 
breakable are they?  Most of the VG kits I've seen recommend GE 50 year 
number II silicone.

Scott

At 08:18 AM 12/5/2003, you wrote:
>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
> >
>
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