CONTROL HORNS

[Woodward James R Civ 412 TW/DRP/ACQ]

Nice one Wayne.  

A simple way to drill the holes for the dowel is to tape your aileron onto
the foam core in its original position.  Then, use a drill press to go
straight up and down.  I've done this a few times and it is easy.  It it
much easier in practice, than in discussion.  You can also try it on a trial
piece too.
Jim


Subject: CONTROL HORNS

Keith......

Don't make such a fuss about this control horn thing.  Go down to Ace
Hardware and get the longest 6-32 bolts you can, about 3-4 inch are
available.  Then in the small hardware section get threaded aluminum sleeves
for 6-32.  These come in 1/2 and 3/4 inch lengths.  These make perfect
standoffs for the control arms, strengthening the rod and an ideal way to
lock the rod to the hard point.(this was Lances idea BTW).   I have had no
problem getting these things to line up with the hinge line.  When drilling
your hard surface for the hardpoint and for the rod.  Put the control
surface temporally on with the hinges in place and place in the shuck half.
Using your drill press take a 1/2 brass tube(tube edge sharpened on sanding
disk) and drill out the surface for the hard dowel.  Do the same for when
drilling the hole for 6-32 rod.  Tap through and then drip thin c/a in the
hole, let cure and retap again to harden the threads.
As Bob P. stated... this system will function just fine. And you wont have
to worry about ordering parts from a foreign country.  Ideally if you can
find some #6 fine threaded bolts it would give you finer adjustment but I
don't think it would be necessary.   I have used the nylon 2-56 clevis on
the elevator pull/pull on my Prophecy that had over 450 flights on it before
it went in and there was little to no wear in the control horn (as per Bob
P.'s recommendation).   I used kevlar cable and it was in good shape also.
Very light and strong setup.

Wayne G.


----- Original Message ----- 
From: "Keith Black" <tkeithb at comcast.net>
To: <discussion at nsrca.org>
Sent: Wednesday, September 03, 2003 11:33 AM
Subject: Re: Control horns, is it just me or... ?


> That looks quite interesting. I do have a couple of concerns however.
>
> Given that the mounting plate (foot) is perpendicular to the arm when the
> arm is mounted on a control surface with an air foil shape the arm will
> actually be pointing backwards away from the hinge line. To avoid this one



> would either need to prop up the back side of the mounting plate or recess
> the front of the plate down into the control surface. With this particular
> design it seems that you'd have to cut pretty deeply into the control
> surface on the leading edge to get the arm to be perpendicular to the
hinge
> line.
>
> Second concern is that the arm is not located on the edge of the mounting
> plate, which means that it would be moved back a bit from the bevel thus
> offsetting the advantage of the longer arm.
>
> I promise I'm not trying to be difficult ;-)
>
> Keith


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