Control horns, is it just me or... ? (follow-up)

[Keith Black]

As a follow-up to my quest to find control horns that extend over the hinge
line I ordered some of the Dubro horns that Brian Young suggested
(http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXEMF9&P=7). These seem to
be the perfect size and EASILY extend over the hinge line for pull-pull
applications, even on the rudder. As Brian pointed out they aren't sexy, but
do the job.

On the sexy side, Tony sent me a pair of Radio South's new anodized
alumninum control horns with the ball-bearing race, these are beautiful!
With the ball-bearing I'm sure they will also be smooth as silk. They're
shaped so they will extend out over the hinge line, however they don't
extend out as far as the Dubros.

Since the Dubro horns allow adjustment up and down I will be using these on
my pull-pull elevator. I feel that the ability to move the control horn up
and down is very important for matching the throws of the elevator halves
when using pull-pull. I also plan on using the Dubro's on the rudder
pull-pull because the longer arm on the horn reaches the hinge line better.

I'll be using the new Radio South horns on my ailerons and would use them on
my elevator if I weren't going with a pull-pull system.

Thanks to everyone for your suggestions!

Keith Black


----- Original Message ----- 
From: "Brian Young" <b4598070 at yahoo.com>
To: <discussion at nsrca.org>
Sent: Wednesday, September 03, 2003 10:04 AM
Subject: Re: Control horns, is it just me or... ?


> Have you seen the new Dubro products? They are
> offering a couple new horns, one at 3/4" offset might
> be about right:
>
> http://dubro.com/du-bro/dub_cat/images/DUB04.jpg
>
> They arent very sexy looking but could work.
>
>

  ----- Original Message ----- 
  From: Keith Black
  To: discussion at nsrca.org
  Sent: Tuesday, September 02, 2003 8:57 PM
  Subject: Control horns, is it just me or... ?


  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.

  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
http://www.centralhobbies.com/buildingtips/mkhorns/mkhornsinst.html. Notice
that in this picture there surface isn't beveled yet and the horn is almost
on the edge.

  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
(http://www.znline.com/produits.php?langue=english&cle_menus=1025879382&cle_
data=1025901639) which means an international order. The other solution I've
found is by RC Model Enterprises
(http://home.att.net/~rc-enterprises/rcme_014.htm) but these control horns
seem very pricey!

  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).

  Is it just me, or have others experienced this dilemma as well?

  Thanks,
  Keith Black

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