REFLECTOR:Trailing Edge

Al Gietzen reflector@tvbf.org
Sun, 25 Jan 2004 09:59:01 -0800


This is a multi-part message in MIME format.

------=_NextPart_000_0040_01C3E329.DBE52E20
Content-Type: text/plain;
	charset="us-ascii"
Content-Transfer-Encoding: 7bit

 

 

>I disagree, at least to a degree, that the vortilons and the VGs play
very 

>different rolls.  The main function of the VGs is to generate a vortex 

>over the upper wing surface at high angles of attack, thereby breaking
up 

>the spanwise flow and encouraging the flow to remain attached.  VGs do
the 

>same thing, most likely more effectively on a smaller scale. So there
is 

>some overlap of function.

 

No VG's have nothing to do with span wise flow. At least not directly.
VG 

or Vortex Generators, create small vortices that excite the boundary
layer, 

this allows or forces ten boundary layer to stay attached to the wing at
a 

higher angle of attack, this can do two things for your,  increase lift
and 

also reduce the wings stall speed.

 

Span wise flow is when the wind over the wing starts to move in an
outward 

direction instead of straight back.

 

Vortilons are a device to reduce span wise flow on swept wings at high 

angles of attack..

 

Scott;

 

I meant to say "The main function of the vortilons is to generate a
vortex 

over the upper wing surface at high angles of attack, thereby breaking
up 

the spanwise flow and encouraging the flow to remain attached."

 

My studies of the tuft testing photos indicate essentially no spanwise
under the wing (except at the tips); and over the wing, little of
consequence except under the separated flow on the aft portions of the
wing at high angles of attack.  This info was primarily from a vari-ez,
some from a long-ez, and a little from Velocity trailer tests, and I
just assume it applies to the Velocity.  There may be differences, but
it seems pretty consistent with theory.

 

Al  


------=_NextPart_000_0040_01C3E329.DBE52E20
Content-Type: text/html;
	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

<html>

<head>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Dus-ascii">


<meta name=3DGenerator content=3D"Microsoft Word 10 (filtered)">

<style>
<!--
 /* Font Definitions */
 @font-face
	{font-family:Verdana;
	panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
	{font-family:Nimrod;
	panose-1:2 4 5 3 5 4 1 2 2 4;}
 /* Style Definitions */
 p.MsoNormal, li.MsoNormal, div.MsoNormal
	{margin:0in;
	margin-bottom:.0001pt;
	font-size:12.0pt;
	font-family:"Times New Roman";}
a:link, span.MsoHyperlink
	{color:blue;
	text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
	{color:purple;
	text-decoration:underline;}
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
	{margin:0in;
	margin-bottom:.0001pt;
	font-size:11.0pt;
	font-family:Nimrod;}
@page Section1
	{size:8.5in 11.0in;
	margin:1.0in 62.3pt 1.0in 62.3pt;}
div.Section1
	{page:Section1;}
-->
</style>

</head>

<body lang=3DEN-US link=3Dblue vlink=3Dpurple>

<div class=3DSection1>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&gt;I
disagree, at least to a degree, that the vortilons and the VGs play very =
</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&gt;different
rolls.&nbsp; The main function of the VGs is to generate a vortex =
</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&gt;over
the upper wing surface at high angles of attack, thereby breaking up =
</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&gt;the
spanwise flow and encouraging the flow to remain attached.&nbsp; VGs do =
the </span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&gt;same
thing, most likely more effectively on a smaller scale. So there is =
</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&gt;some
overlap of function.</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>No
VG's have nothing to do with span wise flow. At least not =
directly.&nbsp; VG </span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>or
Vortex Generators, create small vortices that excite the boundary layer, =
</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>this
allows or forces ten boundary layer to stay attached to the wing at a =
</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>higher
angle of attack, this can do two things for your,&nbsp; increase lift =
and </span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>also
reduce the wings stall speed.</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Span
wise flow is when the wind over the wing starts to move in an outward =
</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>direction
instead of straight back.</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Vortilons
are a device to reduce span wise flow on swept wings at high =
</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>angles
of attack..</span></font></p>

<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>Scott;</span><=
/font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>&nbsp;</span><=
/font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>I meant to =
say &#8220;The
main function of the </span></font><font color=3Dblue =
face=3DVerdana><span
style=3D'font-family:Verdana;color:blue'>vortilons</span></font><font
color=3Dblack face=3DVerdana><span =
style=3D'font-family:Verdana;color:black'> is to
generate a vortex </span></font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>over the =
upper wing
surface at high angles of attack, thereby breaking up </span></font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>the spanwise =
flow and
encouraging the flow to remain attached.&#8221;</span></font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>&nbsp;</span><=
/font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>My studies of =
the tuft
testing photos indicate essentially no spanwise under the wing (except =
at the
tips); and over the wing, little of consequence except under the =
separated flow
on the aft portions of the wing at high angles of attack. &nbsp;This =
info was
primarily from a vari-ez, &nbsp;some from a long-ez, and a little from =
Velocity
trailer tests, and I just assume it applies to the Velocity.&nbsp; There =
may be
differences, but it seems pretty consistent with =
theory.</span></font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>&nbsp;</span><=
/font></p>

<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>Al&nbsp; =
</span></font></p>

</div>

</body>

</html>

------=_NextPart_000_0040_01C3E329.DBE52E20--