REFLECTOR:Vortex Generators on XL
KeithHallsten
reflector@tvbf.org
Sat, 6 Dec 2003 22:47:13 -0800
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Jim,
Yes, the VGs wouldn't be exactly parallel to the airflow at cruise, =
although we really have no need of anything to help keep the flow =
attached at lower angles of attack. The real reason is to make sure =
there is sufficient deflection of the flow while flying at a high angle =
of attack to generate a good vortex!
I'll be interested any any results of trials with trailing edge fences. =
As I recall, previous experiments showed them to have good potential to =
help keep the ailerons effective.
Keith
----- Original Message -----=20
From: Jim Sower=20
To: reflector@tvbf.org=20
Sent: Saturday, December 06, 2003 10:03 PM
Subject: Re: REFLECTOR:Vortex Generators on XL
Keith,=20
Parallel VGs on the main wing makes a lot of sense. I would intuit =
that a little angle (in a direction that would deflect airflow toward =
the root) would be nice since it would generate *something* at cruise =
and keep the flow attached (haven't thought it through enough to explain =
why this might be important :o). Closer spacing of the main wing VGs =
might also help. I'll run it by Jim P. I'm also toying with the idea =
of bracketing the ailerons with fences ala' Vari-EZ. Might help with =
low speed roll authority, and gawd knows we need all the help we can get =
in that department.=20
Something to ponder ... Jim S.=20
KeithHallsten wrote:=20
Scott,...snip .... he recommended that the "crowfoot" pattern of VG =
placement be used on the canard, since it has no sweep, and a little =
slip couldn't dramatically change the effect of the VGs if each pair =
worked either way. However, he suggested placing the VG's on each swept =
main wing all parallel to each other in such a way as to "trip" the =
spanwise flow at low airspeeds and high angles of attack, while being =
nearly parallel to the flow at high airspeeds. ... snip ... Keith =
Hallsten
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<DIV><FONT face=3DArial size=3D2>Jim,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Yes, the VGs wouldn't be exactly =
parallel to the=20
airflow at cruise, although we really have no need of anything to help =
keep the=20
flow attached at lower angles of attack. The real reason is to =
make sure=20
there is sufficient deflection of the flow while flying at a high angle =
of=20
attack to generate a good vortex!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I'll be interested any any results of =
trials with=20
trailing edge fences. As I recall, previous experiments showed =
them to=20
have good potential to help keep the ailerons effective.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Keith</FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Dcanarder@frontiernet.net =
href=3D"mailto:canarder@frontiernet.net">Jim=20
Sower</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, December 06, =
2003 10:03=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: REFLECTOR:Vortex =
Generators=20
on XL</DIV>
<DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT><FONT=20
face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT><BR></DIV>Keith,=20
<BR>Parallel VGs on the main wing makes a lot of sense. I would =
intuit=20
that a <B>little</B> angle (in a direction that would deflect airflow =
toward=20
the root) would be nice since it would generate *something* at cruise =
and keep=20
the flow attached (haven't thought it through enough to explain why =
this might=20
be important :o). Closer spacing of the main wing VGs might also =
help. I'll run it by Jim P. I'm also toying with the idea =
of=20
bracketing the ailerons with fences ala' Vari-EZ. Might help =
with low=20
speed roll authority, and gawd knows we need all the help we can get =
in that=20
department. <BR>Something to ponder ... Jim S.=20
<P>KeithHallsten wrote:=20
<BLOCKQUOTE TYPE=3D"CITE">
<STYLE></STYLE>
<FONT face=3DArial><FONT size=3D-1>Scott,</FONT></FONT><FONT =
face=3DArial><FONT=20
size=3D-1>...snip .... he recommended that the "crowfoot" pattern of =
VG=20
placement be used on the canard, since it has no sweep, and a little =
slip=20
couldn't dramatically change the effect of the VGs if each =
pair worked=20
either way. However, he suggested placing the VG's on each =
swept main=20
wing all parallel to each other in such a way as to "trip" the =
spanwise flow=20
at low airspeeds and high angles of attack, while being nearly =
parallel to=20
the flow at high airspeeds. ... snip =
...</FONT></FONT> <FONT=20
face=3DArial><FONT size=3D-1>Keith=20
Hallsten</FONT></FONT></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
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