Installing control horns requiring 3 to 4 screws and a backing plate of some sort can be a bit of a task. Getting all the holes to line and getting the screws started can be a problem. My solution to this is to grind a point on the end of each screw. The screws seem to find the hole in the backing plate much easier this way. Give it a try!

I tried the grind thing and maybe because I'm a poor builder but I have a terriable time lineing up those holes. the one I'm on now you have to drill first (not treaded screws) and guess what, I missed again! (1/16" to 1/32" off!) Anay more ideas before I do the other half of the wing, tonight? - Please

Trial line up the horn exactly where you want it, mark the covering with a pen/pencil (what ever shows up). When you're happy with the position and have an outline of the horn marked, just add a very small drop of CA and place it back down on the control surface, use a drill of the proper size and drill through the holes, install the screws and back plate and you're done.

I Had this problem all the time too. Then I bought a cheap bench sized drill press. Perfect every time. Don't know how I got along with out it! I think I use it more than I use CA

Dale

Guys!
These nylon horns are horrible--heavy (several grams with the screws) and butt ugly!
I'm cuting my horns (better to say, my plane's horns) from old computer boards (where else can one get thin fiberglass?) and glue them to the structure. Yes, it takes time to dremel them out and to drill the holes, but the result is worth the efforts.

Just my .02 worth,

Boris

How do you use old computer boards? How do you attach them to the control surface without the 90 degree bend? Please tell more, thanks

Have you guys concidered using DU-BRO's Adjustable Control Horn ? Catalog No. 493. One hole, one bolt ! Two minute installation !I'll never stick my fingers again using my awl to line up the holes in those nylon horns !

Ugo

Hey bluesky... I have a bunch of old computer boards... Can you give some details on how you did it?

Come on bluesky, let us in on this computer board tip.

I'll draw a picture and post it here tonight (I'm writing this from my office--hopefully, my boss won't catch me).

I'll draw a picture and post it here tonight (I'm writing this from my office--hopefully, my boss won't catch me).

slowly look over your shoulder :surprised

Ugo has the right idea. They are easy to install and adjust and look good. Why reinvent the wheel? Just my 2 cents. Pete

I find a place on the board, which is free of holes. The best boards are the simpliest ones: old network cards, sound cards, etc. Motherboards are usually multi-layered (there are layers of copper foil inside the fiberglass), which is not what we are looking for.

Using dremel and drill, cut the horm (central part in the picture below) and make a bunch of holes in it. The row of holes at the bottom is for lightness sake as well as for epoxy to fill. I usually taper the lower part of the horn, so that the end fartherst from the pivot (with the smallest hole) is the thinnest.
The horn is glued between two ribs (dark parts in the picture).

I got this idea from Mr. Graham Woods site:
http://www.favonius.com/soaring/bagging/tail_end.htm

Hope this may be useful.
Boris

If you don't have access to old computer boards you can go to an electronics supply store (like Radio Shack) and purchase blank sheets of circuit board material. And you can get the type that does not have holes yet.

Need some clever tips on this still...

Any other good ideas to make sure the drill goes through straight with a 2 screw standard control horn?

Drill press is no good when the surfaces are already glued and hinged on the plane.

Also when the horn is up against the fuse closely what type of long drill bit or tool to use to make the hole since the bulky electric drill forces an angle since it can't get close to the plane?

I usually miss getting the holes straight enough to line up with the backplate 50% of the time lately...

RCadmin: I have found that a piece of piano wire with the tip ground like a nail point works good .You can make it up to 3 feet long if you have arms like a GORILLA !!! big max 1935

A pin vise with a number 80 drill bit works very well.

It's small enough to get into tight places and the small bit doesn't remove too much material to make the threads not hold but allows the bolt to go through when screwed in - it is a very tight fit between the bolt and the material you drilled through.

Jim,

I'm talking about the ones where you have to drill both holes perfectly straight so it goes into the plastic backplate. It would seem easier if the holes drilled weren't that tight. Problem is drilling straight enough so the screws coming out of the other side of the control surface line up with the holes in the backplate.

The pin vise would solve the tight spaces issue but lining it all up so the holes match is still the other big problem.

Like Big Max said, use a piece of wire, I ground mine down like a screwdriver, it will go right through the balsa, and the long drill will help you see the angle you're drilling.

But the real trick is this...

When mounting the horn, get one screw started, but don't tighten it! Then start the other one while the backplate is still away from the surface. Now, if they don't line up, you have room to squeeze the screws together, or pry them apart, or whatever. Once BOTH screws are started, go ahead and tighten them down evenly.

I tried the one to push-pull while the backplate was only started and away from the surface. This works sometimes if your close enough. I've had some surfaces that are very hard balsa and many times that won't work or a wire just won't make it's way through the hard balsa and a drill of some kind is needed. I can stick a t-pin through but it really doesn't work as a guide for any drill since the drill finds it's own way.

Lately I've been using the single hole control horn's by dubro which take the guesswork out of it all. One screw so you can't miss and much faster. Guess the Dubro's could be the ultimate easy solution.

Just like I said 13 replies back, about a year ago on Jan. 25, 2002 !! ONE HOLE- ONE BOLT !!

Ugo

do bro bingo fore sure and look at the new ones for bigger planes

oops du bro

I use this 2 face tape (we used to call it officer tape) stick the control horn down in position..tape holds it very well. Drill pilot hole with pin vice and #80 drill and start your screws.

When finished remove the control horn and the back plate...remove the tape and reinstall. All lined up and neat.

I don't understand how any of the alignment methods so far (except the single hole method or the circuit board method) would help much with tapered control surfaces. The alignment of 4 holes thru a tapered section has always been one of my least favorite building tasks. Dzl