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Old Sep 27, 2013, 01:56 PM
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United States, CA, Lancaster
Joined May 2013
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Build Log
Horten XII - First short kit build

After weeks and weeks of reading and asking questions I've finally settled on a Horten build. It is certainly going to stretch me at my skill level, but should be a fun and rewarding challenge.
My experience amounts to a couple of Goldberg GL type builds, a couple of Zagi wings, and some other misc half build/repair stuff.

After doing a lot of reading on the various thermal and slope forums and watching other build logs, I find that the Horten builds are like crack to me. My drug of choice if you will. So I've purchased a short kit from CPDude, got my skins and rods on hand, and starting the build-out.

I look forward to any advice on the build and tips or tricks in the technique. This one was cut so as to mount an electric motor, but I am not building out that portion. It's going to be a simple wing sloper, so help me God.
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Last edited by Cable; Sep 28, 2013 at 04:22 PM.
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Old Sep 27, 2013, 03:03 PM
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United States, CA, Lancaster
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CPdude cut the short kit for me on this one. I have to say his work is excellent. I am very please with the quality and fit of the parts. As a short kit noob it's a bit of a daunting task to get a kit like this that does not have:
Step 1. Open the box. etc....

But so far the parts make sense. CP has also been very responsive in answering the few questions I couldn't figure out myself with a little study of the build logs.

My building board right now is a part of an oak plank from a prior wood project. It's flat, stable and I can drill into it to mount the jigs, which I like.
This first pic shows the center section jig getting screwed down for the build.

I forgot to take any photos of the center ribs being glued up. (This build log is going to be talking to my fellow noobs, so you pros might get a bit bored).
This section is made of a center rib that contains the upright for the motor cowling protruding from the top, with a matching rib, minus the upright, glued to each side. The center rib is just slightly larger and this part will protrude above the wing covering as many of the other build logs show. The way I glued this up was to simply glue one side at a time, and placing the main carbon tube and two spars temporarily in the slots to align things. I pulled these out after about 20 seconds so they didn't fuse to the ribs (I was also careful with the glue in this area). From there I had to make very minor alignment adjustments based on the internal cutouts on the ribs. Once I was happy with alignment I put some weight on the whole thing and let it set.

Once the center was glued up straight and true I drew a pencil line using the attached rib so the upright could be cut off. See pic 2 and 3.
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Last edited by Cable; Sep 30, 2013 at 08:49 PM.
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Old Sep 27, 2013, 04:00 PM
I don't like your altitude
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Nice one!looking forward to following your progress.
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Old Sep 27, 2013, 04:53 PM
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Cool Stu.

Quick question on cutting carbon fiber tubes and rods if anyone will...
I have a jigsaw, a table saw, and a tile saw. Of these the tile saw does the best job. Is there any concern with getting the rods and tubes wet? I like the idea of the water reducing the dust thrown out. Just want to make sure I'm not hurting the tubes.
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Old Sep 27, 2013, 06:13 PM
I don't like your altitude
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Tile saw sounds like it might work,wrap the cut in masking tape,helps to stop splitting.Water won't hurt,in fact a good way to avoid dust
Junior hacksaw will work,turn the tube as you cut,helps to keep the cut square.
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Old Sep 27, 2013, 10:32 PM
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Has anyone ever tried a tube cutter, used to cut copper pipe? Almost seems like it might work on the CF tubes.

Here are a few pics of the fuse (what do you call it on a Horten?) going together. It's fairly straight forward if you think it through and fit the pieces together without glue a few times.
Also some pics of the battery box, which I put together completely prior to installing in the ribs. I used a large machinists block and magnets to get a square frame on it. The pieces are cut so nicely everything worked out well.

One of the more difficult things for a this noob is figuring out the best order to do things, never having done one like this before.
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Old Sep 28, 2013, 12:52 AM
InceCreations
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Joined Jul 2009
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Is that scratch?
Nice!
Any details on the overall design, how did you make the formers, ribs etc, from 3d design or so ?

I see you use a magnetic building board? I'm looking for such a thing for a while now ....

Vincent
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Old Sep 28, 2013, 04:56 AM
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Cable,
Nice build, I will follow your progress, maybe it will give me inspiration to get mine started when winter sets in. Please keep it up! Lots of pictures and ideas as you build would be great!
Regards,
-Eric
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Old Sep 28, 2013, 05:57 AM
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Quote:
Originally Posted by vincent123 View Post
Is that scratch?
Nice!
Any details on the overall design, how did you make the formers, ribs etc, from 3d design or so ?

I see you use a magnetic building board? I'm looking for such a thing for a while now ....

Vincent
I guess a short kit isn't scratch is it? OK, it feels like it to me though.
No, it's not a magnetic board. Just the steel block and magnets to set the angles on the battery box.
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Old Sep 28, 2013, 06:18 AM
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Originally Posted by ohmite View Post
Cable,
Nice build, I will follow your progress, maybe it will give me inspiration to get mine started when winter sets in. Please keep it up! Lots of pictures and ideas as you build would be great!
Regards,
-Eric
Hey Eric.
You have the same kit? Are you building it with motor and all?
I've seen several build logs on this one and all with motor. I'm going to need to come up with some ideas building it without. I hope to pick the brains of the more experienced here on a few challenges I'll encounter.

The first one being figuring out a good solution to a compartment door for the radio gear in this wing only build. Any thoughts are most welcome.
The birch ply .4mm is very thin and flimsy, more so than I would have thought.
I am thinking about framing up something and creating a "lid" which will screw in. The other thought I had was a possible tongue and groove sliding cover, but I am struggling with how to make that work and keep the foil shape.
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Old Sep 28, 2013, 06:44 AM
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So I tried out the rigid pipe cutter for carbon shaft cutting. It worked fairly well in getting a straight cut, but in the end I could make out hair line fractures, even though I incremented the cut very little in the process. It did get me thinking though that a spinning blade is the better way to go. And then, as an archer it finally dawned on me that they make carbon shaft cutters. A little YouTube searching produced a dozen or so home made cutters as well. search "arrow shaft saw"
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Old Sep 28, 2013, 10:42 PM
Designing something...
United States, CA, Cameron Park
Joined Jan 2004
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A few quick answers...

I just call the "fuselage" are the center section.

I generally cut my carbon tubes and rods with a cutting disk mounted on a small pneumatic die grinder. Water and wrapping with tape are all good.

My access to the battery and such are through the canopy. You can also access the battery box (a little bit) from the sides with the outer wing panels removed. If neither of those will work from you then I'm definitely willing do design and cut something out for you.

Keep the pictures and questions coming.

Regards,
Brian
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Old Sep 29, 2013, 05:17 AM
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Eden NY
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Quote:
Originally Posted by Cable View Post
Hey Eric.
You have the same kit? Are you building it with motor and all?
I've seen several build logs on this one and all with motor. I'm going to need to come up with some ideas building it without. I hope to pick the brains of the more experienced here on a few challenges I'll encounter.

The first one being figuring out a good solution to a compartment door for the radio gear in this wing only build. Any thoughts are most welcome.
The birch ply .4mm is very thin and flimsy, more so than I would have thought.
I am thinking about framing up something and creating a "lid" which will screw in. The other thought I had was a possible tongue and groove sliding cover, but I am struggling with how to make that work and keep the foil shape.
Cable,
Yes I have the same kit from Brian, I have not started it yet though. I've been distracted. Maybe watching yours will provide me some inspiration to start mine when the snow starts falling. I plan to build mine with the motor. I can't provide any advice at this point as you are well ahead of me on your build.
Keep it coming though!
Regards,
-Eric
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Old Sep 29, 2013, 07:30 AM
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United States, CA, Lancaster
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Quote:
Originally Posted by cpdude View Post
A few quick answers...

I just call the "fuselage" are the center section.

I generally cut my carbon tubes and rods with a cutting disk mounted on a small pneumatic die grinder. Water and wrapping with tape are all good.

My access to the battery and such are through the canopy. You can also access the battery box (a little bit) from the sides with the outer wing panels removed. If neither of those will work from you then I'm definitely willing do design and cut something out for you.

Keep the pictures and questions coming.

Regards,
Brian
Thanks so much Brian. This would surely be much more challenging without your support and I appreciate it.

Wrapping tape on the tubes. Nice idea. The tile saw worked very well and cut through the tubes quickly and fairly straight, although I could use a guide on my saw to keep it perfect. Right now it's just by eye and hand, meaning not quite perfect. I cut it slightly long and sanded it to profile, which worked out.

Regarding the battery compartment, I think the wing side access might just be brilliant. I am now thinking I could build a "box" that can slide in and out of the built in battery box with radio and battery contained in it, including connectors for servers mounted on each side. I could even put a charging jack and switch countersunk on one side. The only drawback I can see at this point is the weight of the battery won't be as far forward as it otherwise might. What do you think of this plan?
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Old Sep 29, 2013, 07:38 AM
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United States, CA, Lancaster
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Quote:
Originally Posted by ohmite View Post
Cable,
Yes I have the same kit from Brian, I have not started it yet though. I've been distracted. Maybe watching yours will provide me some inspiration to start mine when the snow starts falling. I plan to build mine with the motor. I can't provide any advice at this point as you are well ahead of me on your build.
Keep it coming though!
Regards,
-Eric
You have to catch up Eric. I need the advice!

I'll confess now that I messed up the first center section and had to have Brian cut me a new one. The mistake I made seemed somewhat miner to me, but Brian was somewhat insistent that I do it again, so I took that advice. I had used the outer wing rib spacing jigs on the center section and they are not exactly the same as the center wing jig. There was 1 or 2 mm difference on the outside rib only, the one the wing would attach to, and the battery box structure barely glued up. It didn't go through the rib like it should. see pic.
All that said, I built out the first section and it has the structure for the motor cowling, so maybe I'll go ahead and finish that one out true to plan. I'm not a big motor guy. Don't like the weight or battery fuss. But my grandson wants to fly something like that, so....
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