Dual Carbon Horns
 

I have been asked on a few occations where I obtained my dual carbon horns, well I made them myself and I thought if there was any interest I would do a make thread (cant call it build thread now can I)

Mike

RE: Dual Carbon Horns
 

I don't need any at the moment, but they are beautiful. Please show us how to make them!

RE: Dual Carbon Horns
 

Someone has been busy with a CNC! Looks good Mike. You're timing sucks - I have been looking for something like this for the project I am finishing and gave up and went with the Hanger 9 threaded horns. How do the non-rudder horns install? Bolt to a hardwood block and glue the block into the surface?

RE: Dual Carbon Horns
 

I'm in too! Also, for those who may not be in need of control horns they may pick up a tip or two for another project of some sort. Thanks in advance as well.

RE: Dual Carbon Horns
 

Great job Mike!

RE: Dual Carbon Horns
 

This style of horn is my fav. CF even better.

RE: Dual Carbon Horns
 

Mike,
I'm looking forward to this build thread...

Mike

RE: Dual Carbon Horns
 

Nice work!! I'm very interested in what you used for plugs and how you made them.

RE: Dual Carbon Horns
 

As there is intrest I will just to give you a taster, there is nothing fancy about these, no CNC machines just basic modeling equipment, and some power tools to make it easier for me, this can all be done with hand tools if needed, due to the time difference between the UK and US its 2445 at the moment and I am going off line, will post more tomorrow, perhaps get the whole process done in one swoop and a couple of posts, but only if the power is on, had a 14hr power cut here today, big anti cyclone in the UK causing lots of problems.

Mike

RE: Dual Carbon Horns
 

looking forward to how you make them

RE: Dual Carbon Horns
 

Now that what I've been looking for! I'll be paying close attention to this one. Joe

RE: Dual Carbon Horns
 

The first thing to do is dertermine if your wing/tail/rudder structure can take the extra width of two horns within the original horn mounting block, if you shine a bright light behind the moving surface you should be able to see the horn fixing block through the wing surface, lightly mark this with a soft pencil or water based marker, from this you should be able to make up your own mind if the fixing block is big enough, if not there are various ways to increase the area, which I will go into later.

Next is to determine the position of the dual horns on the surface, for this you need to have your servo horns sorted and preferably the servo in its final position, you will aslo need to know if you are going to use ball joints or clevis to connect to your servo's this will determine the line of the push rod and the positioning of the dual horns on the surface, although a ball joint will accomadate some misalignement, this error is so small I consider it worth ignoring for the convenience of using the original slot for fixing the horn in a composite surface.

Mike

RE: Dual Carbon Horns
 

It may not be out of place to explain why I do this. Most Composite planes are supplied with what is incorrectly called Phenolic Horns, I say incorrectly as Phenolic is a process and not a material, therefore it is impossible to determine what the original horns are made out of, the first plane I did this on was an Xtreme Composite Edge 2x2, I just did not like the lack of stiffness of them, the next one was a Composite ARF, these horns where in my opinion diabolical, they even came with a warning not to use ball links as the surface would flutter and the horn would break????????? Having now applied a stress test to both of these manufacturers product (give them a good bend in your fingers) the Xtreme Composite will take twice as much abbuse than the Composite ARF, they are also darker in colour and much stiffer and may be able to take a ball link in standard form, although I would not trust them on one of my planes.

Onward:

Next in the line is to source your materials, the way I make mine is with a cover plate too the slots to tidy up the area where you normally see a glue line, this in turn means an extra sheet of material, I use 2mm (0.077") and 0.75 (0.030") carbon sheet obtained from Carbon Copy in the UK, this is a very high quality carbon glass composite sheet, I will find a link and post it latter.

Next how much movement do you need on each surface, you need to know so you can determine the length of your servo arm and horn length, if you are doing this on a 3D machine you will have a long servo arm and possibly a short horn, to get the maximum resolution from your servo's do have the shortest servo arm you can use, even cranking up the ATV too maximum to allow the shortest arm possible, once you have decided on your horn length mark this on a piece of paper from the bottom surface to the hole in the horn using the original horn as a guide, draw around the top and bottom of the oringinal horn to give a rough outline join up the areas and you have your template for the first horn.

Mike

RE: Dual Carbon Horns
 

We now have to do the same procedure for the rudder, I have found that on the ones I have done the servo arm supplied does not match the rudder horn supplied, so you will need to make the rudder horn to match the servo arm you wish to use. Using a similar method to the horns already done make a template for your rudder horn, thats the easy bit done, now on to the cutting.

Mike

RE: Dual Carbon Horns
 

Great job, Bald Eagle;
I like your horns. I usually do the same where ever I see a need for it. I just recently replaced the G10 horns on my Yak with my own, home made CF horns. I have not installed the backing plates, yet. I don't even know, if I really need them. The footing of the horns are so deep into the control surfaces I think it is almost redundant to put some over the horns. I use a special CF sheet we use in our company to manufacture roll scrapers from. It comes in long strips is about 4" wide and approx. 1.4mm thick. Super strong stuff. I use a small abrasive cutting wheel in my Dremel, cut out the rough shape and finish it on my belt sander. Then they are bundled together and drilled in a block at once. That way all holes are in the same position. Fairly easy and quick way and they look really cool[sm=shades_smile.gif]

RE: Dual Carbon Horns
 

theviginian

Nice to see someone else's, the cover plates are there just to hide the ugly glue line you get with a different colour surface, on a white surface like you have the epoxy microballoons will not show up so much, I suppose you could add some food colouring to the mix, but I don't know what that would do to the resin.

First a warning:

Carbon dust is carsonagenic it can and will cause Cancer growths so only cut this stuff in a well ventilated area (outside) and use a particle mask sutiable for carbon dust, being an old full size glider pilot I still have my oxygen mask and bottle, may seem like overkill, but if they are available why not.

I use a band saw to rough cut out four blanks, one of these blanks then has the template stuck to it, the first thing to do is to drill the holes into the blank at the position marked on your template, this blank is then more accuratly cut to line on a scroll saw, using this as a drill jig, drill three other blanks in a pillar drill to get accurate aligniment, ensure the drill used is an interferance fit for the bolts you will use to attach the ball link in this way you can bolt all four blanks together without using a nut on the underside which would stop the block of horns being laid flat on the scroll saw bed when you cut the bolted unit too a more accurate line. Then using a belt sander as theviginian or a bench grinder as I use sand or grind the whole unit to the outline of the original template. Obviously when doing the rudder you only need to make two. The reason for doing four at a time is to ensure the wing or elevator horns are all the same shape. Whilst you have all these bolted together drill a few more holes in the bottom of the horn where it will be inserted into the moving surface, this is to provide a mechanical link through the horn with the microballoon mix to the fixing block.

Next temporaraly put one of the horns into the moving surface and check its positon and if you can get full throw, if your cutting is not that accurate you may need to elongate the slot to provide clearance from the wiper part of the seal.

Bolt two of the horns together with a ball link between to establish the size of the cover plate if you are going to install them, this will also allow you to determine the space needed between the two slots, lay the bolted horns on the surface and mark the second slot position, alternatively use the cover plate. I use a Permagrit pointed file to mark and make the second slot, digging out the bits of the original block with the file, be carefull not to go through the top surface of the wing or tail.

Mike

RE: Dual Carbon Horns
 

Make up template to align your horn at a right angle with the hinge line of the surface, this is to ensure perfect alignement of both sides, with a top hinged surface this is fairly involved, but non the less needs to be done accuratly.

Once your second slot is cut you can put one of the original horns into place against one of your new horns to check the alignement, thats assuming the original slot is in the correct place. If satisfied with the positioning, tape the cover plate into position and cut around the ouside line to remove the plate, this allows you to roughen the area where the cover plate will be glued and to load the slots with microballoon mix without covering the rest of the plane wing or tail with glue.

Mike

EDIT: do remember to roughen the bottom of the horn where it inserts into the wing/tail to ensure a good bond with the microballoon mix.

RE: Dual Carbon Horns
 

Bald Eagle;
Thanks for you detailed description. First off I didn't know about the danger with inhaling the carbon dust. Thanks for the warning[sm=omg_smile.gif]. The way you do it makes more sense to me now. I will drill the holes first and then cut them out. Then screw them together and sand them in a block, duh [X(]. Why didn't I think of it in the first place? [sm=confused.gif] But I do drill glue holes in the footings for mechanical bonding strength as well. Good to find out those square plates are not really needed for strength. My glue joints look clean. No need to cover anything ugly.
Thanks again for the great tips, Bald Eagle
thevirginian

RE: Dual Carbon Horns
 

I have found it best to take the tape off the cover plate as its very awkward to get in between the horns once in position, Put the cover plate on the horns and move up the horn out of the way of the area to be inserted into the wing/tail, Load the slots with a microballoon mix until nearly flush with the surface, push the horns into position and wipe away the excess glue with a rag or cotton bud wetted out with lighter fluid, put your alignement template in position and check all is true and to your liking, put some glue back onto the roughened surface under the area to receive the cover plate and lower into position, with a cotton bud wipe away all the excess glue from around the edge of the cover plate and between the horns and recheck the position of your template, leave to set fully.

Mike

EDIT: I forgott, in the time honoured traditions of all instructions: "repeat above three more time to complete".

RE: Dual Carbon Horns
 

The rudder on the ones I have done have all been the same, only a support block on the lower part of the rudder, this does not suit our purpose, what I have done is to open up the area between the two rudder horns completly to make a big slot and inserted a balsa former above the top horn, I have not got a picture of that I am afraid, make up a template to ensure the rudder horn is symetrical about the hinge line and in line with it, did I say you need to do this before you attach the rudder to the fus, glue the top rudder horn to the newly installed former only, ensure there is sufficient glue inside the hole through the horn, allow to go off, make up another former to go inbetween the two horns and glue in place, allow to set, take the second rudder horn and put tape on the areas you do not wish to get glue on, put lost of microballoon mix into the slot and insert the second horn and bolt through the template into the first horn and check the alignement and that all is square too the rudder, clean the horn and surrounding area with a cotton bud and lighter fluid, you can fix the cover plates if you are using them after the horns are set into position.

Once you have the rudder horns completed you can set out the holes needed to feed the pull pull cables through, I have included a few pic's of how I do it below.

If anyone has any question of feel something is not clear, please ask and I will do what I can to clarify.

Mike

RE: Dual Carbon Horns
 

Again, very nice description of yours. Certainly helped a lot.
thevirginian

RE: Dual Carbon Horns
 

Your welcome just gald someone found it usefull.

Mike

RE: Dual Carbon Horns
 

great stuff, thanks!

RE: Dual Carbon Horns
 

Mike,

Can you provide more detail on the installation of the rudder horn? I think I know what you are saying regarding "what I have done is to open up the area between the two rudder horns completly to make a big slot and inserted a balsa former above the top horn"

However, I want to ensure that I have this right... I am planning on making a set of these for a Xtreme Composites 2.6m edge and I want to ensure that I get it right...

Thanks!

RE: Dual Carbon Horns
 

CCDave

Once I had cut out the second slot there was no balsa block above the top horn to glue the horn too, so I cut a piece of balsa the shape of a section through the rudder and inserted this into the rudder above the slot to support the horn, this was glued in with microballoons, I then turned the rudder upside down and glued the top horn to the inserted piece of balsa, this was easily accomplished by inserting the glue into the centre hole of the horn, leveling the glue to the horn, I then glued another piece of balsa the thickness of the gap between the two horns into the rudder, once this had all gone off I glued on the second horn onto the new piece of balsa and the original balsa block below that, it sounds more difficult than it is, its a bit messy so have some cotton buds and lighter fluid to clean up the mess with hanndy.

The templeate was easy to make as well, by putting three holes in it, one for the rudder hinge wire to go through and two others in line the horn width apart for the bolts to go into, this keeps it all in line whilst the glue sets, draw it out first and then cut slots in it to allow it to fit inside the rudder hinge point, I think the pic helps to see what I mean.

Hope that helps.
Mike

EDIT: to add drawing of template