I am trying to install control horns on my ailerons with difficulty.
Everything is lined up on the ailerons with the last hole protrouding out of the aileron hinge line.
The problem is when I marked and drill the holes I cannot seem to get the hole to come out in the right place on the top of the aileron.
It looks like I'm lined up when drilling.
Is there some sort of trick to doing what should normally be an easy task?
Included is a pic of the control horns.

You probably realize that the aileron is tapered. So, this does not present a square for the hole to be drilled. One thing you can do, and i'm sure you will see that there are probably a dozen or more different views.. is to push a T pin through the hole in the top of the control horn through the aileron in what you feel is to the right place on the bottom part of the horn. This may take a few trys until you get it right (I won't say square because it clearly is not). Once you do get it right, you can wiggle the pin a bit to make sure that the right hole is used as a guide and drill through with a very small drill and center that. Then follow through with the right drill and it should line up ok.

Remember that this is balsa you are working with, and is very soft. What I do after the holes are drilled and centered right on both the top and bottom, is to put a drop of CA into the hole and, once it is set, (give it a good half hour), chase the hole with the correct size drill and then permantly mount your horn.

Just remember to line up the control horn with the hinge line. (the part with the four holes that the clevis attaches to is to be perpendicular to the hinge line)

CGr.

You can enlarge one of the holes (Or both) if you need to. It's the clamping action that holds it in place more than the screw holes.

I'd have to agree with MinnFlyer, I posted a similar comment a while back. It's frustrating when you're trying to do a perfect job and taking pride in your aircraft and then you can't drill a straight hole for a control horn. Been there, done that. Try not to poke a hole in the covering and drill just far enough to see where the drill is trying to exit at and work it over closer to the hole in the horn. Use the clamping action to do the job. It's not ideal, but it works.

Yeah, kind of frustrating. I'm glad it's just not me. Seems like such a simple task but I'm new to building and one things for sure. you are always learning (which is the fun part)

I can tell ya that for each and every plane I assemble, the worse part is installing the control horns. That's mainly because I, just like you, and obviously others.. have a tough time getting those darned things lined up correctly, and end up with a hole that is much larger than I had anticipated. And Minnflyer is right.. all you have to do is clamp them down right and they work fine.

I've seen people drill out a 1 inch hole, then fit in a hardwood dowl cut to match then sanded down to match the taper of the aileron, rudder, or elevator, then drill through that. They call it a hard point. I've never done it. I use the CA in the hole method to harden up what's underneath the control horn mounts. And from what I've been reading it's probably not necessary. But I still do it. Can't hurt, I guess, because it does harden things up a tad under these things. The added CA will fuel proof the bare wood if you should happen to tear the covering under the hinge. At least that's what I think happens. Maybe or maybe not... but I still do it.

CGr.

An oblong hole will not hurt, put CA in to stiffen the wood.
I like airplanes that put a ply block in the ailerons, where all you need to do is drill through the block and install screws into the block iself. no need to drill all the way through and no need for a backing plate. Seems like such a simple thing to do during construction and would be an easier assembly for the beginners I don't know why manufacturers don't incorporate this into trainers.

You probably could do that for most aircraft ailerons. I've thought about doing that on occasion, but just did the oblong hole thing and hit it with thin CA.

That Seagull Super Star 120 I have is an example of one that could really use the plywood buildup. I drilled through that and used one of those stud type control horns but the balsa was in no way strong enough for that, so I removed it and will probably go with your suggestion on that plane, for all surfaces.

I've even seen guys that removed covering around the control horn point, then carefully cut into the balsa to create a bed for a piece of ply, then epoxied it in place. That made one nice hardpoint. And looked pretty neat to boot.

CGr.

Yup the biggest problem is getting the holes aligned because you are effectively drilling at an angle.

I've had much better luck since I started using a drill press, with a wooden shim under the wing, etc., which is to be drilled.

Of course this requires that you drill the holes BEFORE you start assembling your ARF, but usually this is easy to do.

I've taken to starting with the motor and cowl, then control horns, before moving on to the rest of the plane.

My problem with aileron horns has always come after the holes are drilled. Those damnable slot head screws they provide... Have you any idea how many freshly built wings I've had that screwdriver slip and pop a hole thru the brand new covering on[:@]? Well, only 2 so far, but that's 50% of my builds! Are phillips, robertson (square to the yanks) and hex head screws that hard to package!!!! I've just payed 3 bucks for a gram of nylon and 4 slot screws, come on!

Sorry. Pet peeve.

J

Standard head screws blow for servo horns... I know your pain.

somegeek

Another way around the problem is to throw the horns away and use these:

http://www.shopatron.com/product/par...161.5164.0.0.0

My last build, the Pipe Dream, I made my own horns of aircraft ply. Built right into the structure. No screws. Bliss.

I have those on my Showtime, love em.

Me too ! Me Too ! One Hole, No Muss, No Fuss ! And no stuck fingers trying to line up the holes with a drill ![X(]

Ugo

Minn Flyer.
I have some of these laying around! Being new I was apprehensive to use them.
They look simple enough, however, don't you have the same problem with aligning the single bolt ie crooked, etc or is this the same principle? A little larger hole for proper alignment/fill in the hole with balsa/ca, clamp it down and you're done. right?

Right

MinnFlyer

Do they make these large enougt to use on my SeaMaster 120 with a Magnum 1804s.

Yes:

http://www.shopatron.com/product/par...161.5164.0.0.0