<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2800.1226" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial size=2>Do you have pictures?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Keith</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=fmiller2@sc.rr.com href="mailto:fmiller2@sc.rr.com">Buff Miller</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> Friday, September 05, 2003 8:42
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Control horns, is it just me
or... ?</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Keith,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I've been following this thread for the past few
days with great interest. The discussion has been very informative and
interesting, but I have to throw in a concept that has yet to be
mentioned. I suspect everyone has been "to close to the forest to see
the trees" thinking control horns and geometry. I've been using a system
for the past ten years that I developed from an article Gene Rogers, former
District 6 VP, covered in the K-Factor back in the early
1990's.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>This system does <U>not</U> use control horns
for the pull-pull setup on the rudder. It uses two equal diameter
pulleys. One on the rudder the other on the servo. I make the
pulleys out of ply, three circles sandwiched together. The two outer
circles of 1/32" ply are roughly 2 - 2 1/2" in diameter. The inner
circle is of 1/16" ply about 1/8" - 3/16" smaller in diameter. I bevel
the edges of the two outer circles so that when I glue the three circles
concentrically together they form a "V" pulley. Also, dremel two notches
in the "V" for the cable ends to pass out and back into the "V" much
like a Hanger 9 aluminum servo wheel to enable anchoring the cable to the
pulley. Drill a small hole for a tiny wood screw, no larger
than a #2. On the servo pulley the middle of the cable can duck out of
the "V" pass under the washered wood screw and back into the "V" on the
other side of the screw. The loose ends of the single cable will pass
under and around the wood screw of the rudder pulley.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Install the rudder pulley in a slot cut in the
rudder equal to the thickness of the pulley, 1/8", and a depth of the radius
of the pulley. Make certain that the center of the pulley is centered
right at the edge of the bevel or hinge line of the rudder. This keeps
all of the geometry intact. Epoxy it in place after MonoKoting the rudder
but prior to hinging the rudder to the fuse. Nearly one of the last
steps in the construction of your plane. In preparation for the pulley
cut a similar 1/8" notch, also equal or slightly larger than the radius of the
pulley in the fuselage. I epoxy a balsa block internally in this
area if it is an fiberglass fuse to beef up this area.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The servo pulley is simply bolted with two 2-56
socket head bolts to a round servo wheel. All tightening of the cables
are done at the rudder pulley outside of the fuse.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The main advantage of this system is that the
servo is able to maintain constant torque on the rudder through out the
entire deflection of the rudder without any cable slacking or binding
issue. Plus you couldn't get any other system much cheaper. You
can also increase the torque of the servo, at the price of reducing the
throw of the rudder, by making the servo pulley smaller in diameter than the
rudder pulley. Or, increase the throw of the rudder, at the price of
reducing the torque of the servo, by making the servo pulley larger than the
rudder pulley. If the rudder is positioned quite far back in relation to
the elevator, such as on a CAP 232, the rudder could in theory be made to
rotate nearly 150 degrees or more assuming you double bevel the rudder and
fuse at acute angles on the hinge line.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Just another idea to consider. It almost
took longer to write this explanation than it takes to make such a
system. Enjoy.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Buff Miller</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=tkeithb@comcast.net href="mailto:tkeithb@comcast.net">Keith
Black</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> Tuesday, September 02, 2003 9:57
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Control horns, is it just me
or... ?</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>When it comes to control horns for pattern
planes it seems to me that some of the most commonly used choices have a
major flaw.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>On my last plane I used the MK Aluminum
Horns on all surfaces except for the rudder where I used the IM pull-pull
horns. Both of these are nice horns except they have a major flaw when using
a pull-pull setup. The flaw is that the little black plastic arm that screws
onto the horn and connects to the clevis is so short that it doesn't extend
out over the hinge line. I know that with pull-pull systems it isn't
*absolutely* necessary for the connection to be exactly above the hinge, but
the further back it is the more slack there will be in the cable that is not
pulling. In my opinion with these horns the connection point is too
far away from the hinge unless the horn is virtually mounted on the
control surface bevel (especially when it comes to rudder). This can easily
be seen in these "instructions" for installing the MK horns <A
href="http://www.centralhobbies.com/buildingtips/mkhorns/mkhornsinst.html">http://www.centralhobbies.com/buildingtips/mkhorns/mkhornsinst.html</A>.
Notice that in this picture there surface isn't beveled yet and the horn is
almost on the edge.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>On my new plane I wanted to avoid this problem
so I did some searching to find a better solution. To begin with I looked
for a longer arm to connect to the MK horn, one that would extend out to the
hinge line. I found two options from Sullivan but both require too big of a
horn thread (6-32 and 8-32). My search then led me to two other choices that
seem to be good alternatives. The first is the ZNLine aluminum control
horns, but these are apparently only distributed by ZNLine (<A
href="http://www.znline.com/produits.php?langue=english&cle_menus=1025879382&cle_data=1025901639">http://www.znline.com/produits.php?langue=english&cle_menus=1025879382&cle_data=1025901639</A>)
which means an international order. The other solution I've found is by
</FONT><FONT face=Arial size=2><FONT face="Times New Roman" size=3><FONT
face=Arial size=2>RC Model Enterprises</FONT> <FONT face=Arial
size=2>(</FONT></FONT><A
href="http://home.att.net/~rc-enterprises/rcme_014.htm">http://home.att.net/~rc-enterprises/rcme_014.htm</A>)
but these control horns seem very pricey!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If anyone could point me to a longer 3mm
connecting arm that will fit on the MK and IM horns I'd be happy (BTW, I've
used the MK BB connectors on the MK horn and they still aren't really long
enough).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Is it just me, or have others experienced this
dilemma as well?</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>Keith Black</FONT></DIV>
<DIV> </DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>