Control horns, is it just me or... ?

[Keith Black]

Troy,

Actually I'd looked at these on the central hobbies web site but there were some things that concerned me about them. 

1. From the picture I couldn't tell what the base was made of or how the horn was connected to the base and I wasn't sure how sturdy it was.
2. It didn't look like there was much of an angle and I wasn't sure that it would be enough to allow that tiny arm to reach the hinge line.
3. Initially I was concerned about it being mounted on the surface with ply and not having a rod go through to the other side, though I've since learned that this is also how the ZNLine horns are mounted.
4. And finally, I felt that a single rod through the surface would be easier to align evenly on each side, assuming that I can drill a straight hole :-) 

Given that you've had good luck with them it sounds like they should work fine. How would your respond to my concerns #1 and #2?

BTW, I hope you can make it to the Hot Springs contest. After reading all of your informative posts it would be great to meet you.

Thanks,
Keith Black 
  ----- Original Message ----- 
  From: Troy Newman 
  To: discussion at nsrca.org 
  Sent: Tuesday, September 02, 2003 9:53 PM
  Subject: Re: Control horns, is it just me or... ?


  MKD0815 Offset Aluminum Horn Medium size

  http://www.centralhobbies.com/control_linkage/control_horns/mkd.html

  They work well I have them on my Flashdance...(Artistic Aero) model huge control deflections and huge surfaces.

  I also ran them on my Hydeaway on the Rudder...Super Easy to install...I use a Dermal Router attachment and countersink a piece of ply into the surface. By the way I stick a piece of balsa in the surface also then router it out....Sand flush and its a done deal...Never had an issue yet..Hydeaway has around 500 flights and last I heard its keeping the new owner very happy.

  So they are an option.....

  TN
    ----- Original Message ----- 
    From: Keith Black 
    To: discussion at nsrca.org 
    Sent: Tuesday, September 02, 2003 9:57 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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