REFLECTOR:Vortex Generators on XL
Scott Baker
reflector@tvbf.org
Sat, 6 Dec 2003 15:42:15 -0500
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Those who are working on testing new VG placements ... keep up the good =
work!
Nothing about the Velocity placement guide is sancrosect. The company =
collaborated with the VG supplier, who recommended a pattern/placement =
guide based on (I think I'm correct on this) 20% MAC. There have been =
no wind tunnel or computer model tests to verify if the VG's are in the =
best/most efficient location - or not. So we are all giving it our best =
guess.
The VG placements on the standard wing resulted in excellent benefits - =
the stall speed was lowered a good 5-knots, with very little (no =
noticable) penalty on the top end. The VG's on the big wing (XL and =
173's) help some - but their effectiveness does not stand out as good as =
on the standard wing. I personally don't care for the performance of =
the VG's on the big wing (based on the present template).
Is there room for improvement? I'm sure of it! Lon Arnold, pilot of =
the Becker Avionic Systems aerobatic Long EZ has done a lot of field =
testing of VG's on canard aircraft - which differ from conventional =
wisdom - and he is obtaining excellent success. Ask him about this when =
you say "Hello" at some future air show.
I am really, really, really hoping that Jack Sheehan will team his =
Velocity XL up with Old Dominion University, who runs the full scale =
wind tunnel at the Langley Research Laboratory in Hampton, Virginia. =
The folks at ODU have introduced the idea to do this for free (that's a =
good price) - and it's just a matter of working out the timing and the =
details. It would be great to do actual wind tunnel testing to =
determine the best VG placements for the XL.
Scott B.
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<DIV><FONT face=3DArial size=3D2>Those who are working on testing new VG =
placements=20
... keep up the good work!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Nothing about the Velocity placement =
guide is=20
sancrosect. The company collaborated with the VG supplier, who =
recommended=20
a pattern/placement guide based on (I think I'm correct on this) 20% =
MAC. =20
There have been no wind tunnel or computer model tests to verify if the =
VG's are=20
in the best/most efficient location - or not. So we are all giving =
it our=20
best guess.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The VG placements on the standard wing =
resulted in=20
excellent benefits - the stall speed was lowered a good 5-knots, with =
very=20
little (no noticable) penalty on the top end. The VG's on the big =
wing (XL=20
and 173's) help some - but their effectiveness does not stand out as =
good as on=20
the standard wing. I personally don't care for the performance of =
the VG's=20
on the big wing (based on the present template).</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Is there room for improvement? =
I'm sure of=20
it! </FONT><FONT face=3DArial size=3D2>Lon Arnold, pilot of the =
Becker Avionic=20
Systems aerobatic Long EZ has done a lot of field testing of VG's on =
canard=20
aircraft - which differ from conventional wisdom - and he is obtaining =
excellent=20
success. Ask him about this when you say "Hello" at some future =
air=20
show.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I am really, really, really hoping that =
Jack=20
Sheehan will team his Velocity XL up with Old Dominion University, who =
runs the=20
full scale wind tunnel at the Langley Research Laboratory in Hampton,=20
Virginia. The folks at ODU have introduced the idea to do this for =
free=20
(that's a good price) - and it's just a matter of working out the timing =
and the=20
details. It would be great to do actual wind tunnel testing to =
determine=20
the best VG placements for the XL.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Scott B.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV></BODY></HTML>
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