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<DIV><FONT face=Arial size=2>Yikes, that's plenty of travel
alright.....about 10 degrees with 45% expo on the ailerons feels
pretty</FONT></DIV>
<DIV><FONT face=Arial size=2>good to me....I'm with Vicente, I'd cut down the
throws first to about 12 & 10 degrees for high & low</FONT></DIV>
<DIV><FONT face=Arial size=2>rates respectively and you should feel he
difference (that's if you own a JR ;-) ....Not sure what class you</FONT></DIV>
<DIV><FONT face=Arial size=2>fly, but 10 degrees was just fine for Masters and
FAI for me.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>How sharply rounded is your TE?......Can you send
us a picture?....However, now that I see how much</FONT></DIV>
<DIV><FONT face=Arial size=2>throw you have on your ailerons, reducing them will
be the first, easiest step.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Below, please read my aerodynamics guru friend's
response to our thick versus thin TE curiosity. He</FONT></DIV>
<DIV><FONT face=Arial size=2>is a very knowledgeable fellow in full size &
R/C and he and I did a few RPV projects as well. Those of</FONT></DIV>
<DIV><FONT face=Arial size=2>you who remember the man powered airplane, this
fellow was one of the three engineers on the project...</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>He and I have talked about this in the past also, a
thin/sharp TE is less sensitive around center and a </FONT></DIV>
<DIV><FONT face=Arial size=2>thicker/squared off TE is more sensitive around
center.....On a 2 meter pattern ship I flew with a sharp</FONT></DIV>
<DIV><FONT face=Arial size=2>TE, the aileron sensitivity wasn't an issue and
trim held perfectly on the ailerons. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Take a minute and read please, Amir...</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2><FONT face="Times New Roman" size=3>The lift of an
airfoil is strongly determined by where the flow detaches<BR>at the TE.
This is REALLY strong function. A few degrees more or less<BR>around a
rounded TE can make a huge difference in lift. there have been<BR>some
planes flown where they did a round TE and blew some high pressure<BR>air out of
a slot just ahead of the TE, and could control the plane by<BR>varying the
amount of air blown.<BR><BR>Here is a somewhat Techie article on the
subject:<BR><</FONT><A
href="http://www.fluent.com/solutions/articles/ja153.pdf"><FONT
face="Times New Roman"
size=3>http://www.fluent.com/solutions/articles/ja153.pdf</FONT></A><FONT
face="Times New Roman" size=3>><BR><BR>I worked on a project at Lockheed 25
years ago that was trying to do<BR>that for a helicopter rotor.. and you could
stop the rotor in an X<BR>configuration and then use it as a wing. Since
half the airfoils went<BR>backwards in heli mode compared to wing mode, the idea
had some merit.<BR><BR>Anyway, for models, if you do that on a control surface,
you are likely<BR>to not have as linear response as you would like.<BR><BR>now,
sometimes, a sharp TE has problems on models. The low Reynolds<BR>Numbers
mean thick boundary layers, and quite often the control surface<BR>spends a lot
of motion wiggling around in the boundary layer with<BR>minimal lift
change. Probably not a problem with 1/3 scale stuff or F3a<BR>stuff, but
it can be an issue.<BR><BR>So, a moderately thick, squared off TE is the
compromise. Still sharp<BR>edges, so you know where the flow separates,
but the thickness gets it<BR>out of the boundary layer faster. The CL
stunt guys had it right.. flat<BR>flap on the back of a symmetric wing, with a
concave cusp at the hinge<BR>line. Its going to be VERY sensitive around
neutral, so good servos,<BR>good linkages are mandatory, and then soften the
response as needed in the TX.</FONT><BR><BR></FONT></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=paul.horan@sbcglobal.net
href="mailto:paul.horan@sbcglobal.net">paul</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, December 05, 2005 4:11
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Excess Aileron sensitivity
around neutral</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Eric,</FONT><FONT face=Arial size=2> Regarding
mechanical advantage, The radius on the servo arm is 15 mm, the aileron
control horn is 25 mm. The battery shows 5.2 volts under
load.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Jim Ivey, Aileron deflections are 15
degrees low rate 18 degrees high rate.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Del and Amir, The trailing edge of the
ailerons is sharply rounded. The TE is 1/8 " width at the end
and has a 1/16" radius. </FONT></DIV>
<DIV><FONT face=Arial size=2> </FONT></DIV>
<DIV><FONT face=Arial size=2>Thanks,</FONT></DIV>
<DIV><FONT face=Arial size=2>Paul</FONT></DIV></BLOCKQUOTE></BODY></HTML>