4.1 meter (1/5 scale) Horten IIIe - RC Groups
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Oct 14, 2011, 01:00 AM
Designing something...
Build Log

4.1 meter (1/5 scale) Horten IIIe

Since I'm now done with my 2m Horten XII build I decided it was time to start building my 4.1m Horten IIIe. I finished the CAD design and cut most of the parts out on the laser a few months back.

The Center Section...

Since I designed the parts to interlock everything is going together pretty quickly. What you see here took about one hour to put together. I still need to glue a couple of 1/8" bass wood longerons in place and do a some sanding before I can glue the top skins in place.

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Oct 14, 2011, 02:07 AM
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yyz's Avatar
Fantastic. You must be one of the few people on earth doing this level of work using sharks with friggen lasers on their heads!

Keep up the good work,

Oct 14, 2011, 02:36 AM
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Highfly!'s Avatar
Oct 14, 2011, 10:55 AM
Lbuff1's Avatar
Very cool.
Oct 14, 2011, 12:36 PM
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Are you a bodybuilder also??Keep up the great work!! Arnold will be proud of you!!!Paul
Oct 15, 2011, 07:56 PM
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More progress on the center section

I had to do a bit of sanding on the bulkheads since they needed to be beveled to match the shape of the ribs. Once the sanding was done the skins were then cut to size and glued in place. It took three pieces per side. Each piece is 12 inches wide so that's about 28 inches of center rib I had to cover with plywood. This thing is going to have lots of wing area...about 1,650 dm2.

Last edited by cpdude; Oct 16, 2011 at 10:39 PM.
Oct 16, 2011, 08:59 PM
Designing something...

More on the center section + left wing panel

Well I managed to get some work done today.

The center section...
I finished the canopy frame.

I also finished framing of the hatch that will cover up the mid cabin area. This will allow me to get to the motor mount nuts and the prop shaft coupler.

The left wing panel...
I finish laser cutting the servo covers, the sub-leading edge parts and the rib alignment jig.

I mounted the ribs to the building board using the alignment jig and glued part of the sub-leading edge in place (the horizontal parts that interlock with the ribs..

I glued the wing joiner tubes in place.

Next up...
Cutting the spruce spar caps out of the table saw.
Gluing the rest of the sub-leading edge parts in place.
Cutting out the shear webs.
Finish the plug and then pull the canopy.


Last edited by cpdude; Oct 17, 2011 at 07:39 PM.
Oct 17, 2011, 08:54 AM
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Peter V's Avatar

4.1 mtr Horten

Hello Brian,

txs for the link.

Awesome job.

what kind of tubing are you using? And is tehr rod massif or hollow?

and pse, lots of pictures. Do you have also pictures of your cutting machine?
Am interrested in.

Oct 17, 2011, 10:17 AM
Designing something...
Hey Peter,

The joiners are thin walled (.049") aluminum tubes with Phenolic sleeves (sockets). The front tube is 1 1/2" diameter and the rear is 5/8" diameter. The front tube has been anodized black.

I have some discussion and pictures of my laser(s) on my rcgroups blog. The newer and bigger laser is based on the 2.x laser design available at Buildlog.net. I extended both the X & Y axes so I can reliably cut 620mm X 470mm. Both of my lasers use 40W CO2 laser tubes. This allows my to easly cut 6mm lite ply and 3mm birch ply. I get some more pictures posted.

Oct 17, 2011, 12:30 PM
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eschlitzkus's Avatar
Looks great!! It is a lot of CAD work to get to this point. How fast does the laser run? My CNC router can go 18 inchs per minute.

Oct 17, 2011, 05:02 PM
Designing something...

Yes, lots of CAD work! My laser isn't too fast since it's only using a 40W CO2 tube. The speed varies a lot depending on what I'm doing (cutting or engraving) and the material.

Here are some examples:

-I can engraving part numbers and such on most wood at 60 inches per minute with about 1-2% power.
-I can cut through 1/8" medium balsa at the same speed but with about 30% power.
-I can cut 1/8" poplar plywood cuts at about 24 inches per minute with about 85% power.
-I can cut 1/8" birch plywood at about 12 inches per minute with about 90% power.

Last edited by cpdude; Oct 17, 2011 at 05:46 PM.
Oct 18, 2011, 11:21 PM
Designing something...

The belly skin and other stuff on the dirty side

The slots for the spar caps need to be beveled in order for the spar caps to fit. So I did a bit of sanding. I got bored with that pretty quickly, however, I didn't have much interest in firing up the table saw to the spar caps. So what was I to do?

I decided to do some more work on the bottom of the center section. The first thing I did was to sheet the aft part. The trailing edge was reinforced with epoxy and flocked cotton.

Next up I decided to do a little work on the landing "pod". Okay, I'm sick of calling it the landing "pod" so if anyone know what thing on the bottom of the center section that holds the wheel is called please let me know. After a bit more sanding I'll sheet it with .4mm birch plywood. By the way, I'll be using a 3" wheel.

Oct 19, 2011, 12:13 AM
Designing something...
Originally Posted by Peter V
Do you have also pictures of your cutting machine?

I've posted some pictures on my rcgroups blog.

Oct 20, 2011, 01:25 PM
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1967250s's Avatar
Has anyone ever built the Horten X glider, or the VI as a model?
Any plans available?
Nice build thread, by the way. I'm wondering how nicely these would fly with modern foils and materials in full size. I just read a bunch of stuff from NASA, MIT, and University of Missouri that suggest there were lots of design snafus, flying deficiencies, and weight problems. I love the planform, just beautiful, but can you imagine if Schleicher or Lange made a new one? Better L/D and handling. Lighter and more durable materials. Just looking at the cockpit framework, all the tubes and fittings that they used on the originals, makes me shudder. Makes me think of the Swift hangglider that was designed and flown by college students. How about a pod under the Horten wing? 2 seats?
Oct 20, 2011, 01:47 PM
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1967250s's Avatar
From TWITT.org ( the wing is the thing!)

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