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Old Jul 05, 2011, 11:08 AM
cpdude is offline
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Designing something...
I've got some PMs from people interested in getting laser cut short kits. So here's the deal. I can cut short kits for the 2m & 2.6m Horten XII, the 3.4m Horten XVI, the 4m Horten XIV and and the 1.5m Horten Micro-Elli.

I will also be able to make short kits for my own 4.1m Horten IIIe pretty soon. Here's the link to the IIIe: https://www.rcgroups.com/forums/show....php?t=1455941.

Just send me a PM if you're interested.

Brian

p.s. I'll post some links on my rcgroups blog soon.
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Old Jul 20, 2011, 12:16 PM
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Designing something...
Not too much to update. Been too busy between vacation and work to get much done. I did manage to get the to skins on the other wing panel and get it removed from the wing jig.

I'll get some pics up soon.

Brian
Old Jul 21, 2011, 10:09 AM
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control surfaces


Brian,
The type of covering will have an effect on it's rigidity. Of the iron on films,
Monokote seems to add the most stiffness. Also consider adding shear webs inside the aft edge of the aileron sheeting. Any type of box structure is a help.
Ken

Quote:
Originally Posted by cpdude View Post
Well I've made a bit more progress on the XII. I've got a good portion of the top of the left wing panel skinned. I've also got the main and front shear webs glued in place. I'm very happy with how the laser cut shear webs fit!

What have I learned so far. One thing is that I made the face of the sub-leading edge a bit too short. I've corrected the drawings so that the face now extends about ~42mm past the last rib and blends into the tip.

I'm also concerned that I may have removed too much material from the control surfaces. It's obviously very important that they are as ridged as possible to avoid flutter. My plan at this point is to add some carbon fiber to the trailing edge.

Brian
Old Jul 21, 2011, 10:29 AM
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Designing something...
Hey Ken,

I frankly hate the "new" monokote! Anyway, I will not be using an iron on film covering. I will probably be using polyspan.

The aft spars and control surface spars will all have .4mm birch plywood shear webs. The front of the control surfaces and the wing openings will be faced with the same.

Brian

p.s. I'm almost done cutting yours.
Old Jul 21, 2011, 10:45 AM
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Brian,
I am giving thought to using silk and dope like the old days. A translucent wing would be so cool! But I worry how well it would hold up. Maybe something like Sig Koverall. Films don't like to stick to plywood anyway. This is a worry on the SuperHawk I am building (larger, modern version of the HobieHawk) as the wing skins are all ply, but need Monokote to provide torsional rigidity.
Ken
Old Jul 21, 2011, 10:48 AM
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Designing something...
I've got some Koverall so that's definitely an option. I haven't been completly happy with silkspan. I use some on my Horten XVI and it has proven to be a bit fragil. I've started covering my Horten XIV with polyspan and it seems much more durable at this point.

Brian
Old Jul 26, 2011, 09:30 AM
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WAY COOL!
I see that my short kit is on the way. This project sometimes keeps me awake at night thinking. I designed a mirror grinding machine and award winning 12.5" f6 telescope on sleepless nights. Now if I can just find info on the landing gear.
Ken
Old Jul 26, 2011, 11:38 AM
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Designing something...
@Ken - Just an FYI...the plane isn't designed to use landing gear. It have been designed to use a bungee launch. However, as with most things it can probably be modified.

I attached a few pictures of the XII showing the gear. Several of the pictures are of a mockup.

Enjoy!

Brian
Old Jul 26, 2011, 12:12 PM
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The pics I was able to find show 2 smaller front wheels in the wings and one large rear wheel that carried about 60% of the weight. Front wheels retracted back, the back wheel retracted forward.

I do have a glider retract that should work for the main, a couple of light retracts should work for the front. Steering is going to be.. interesting.
Old Jul 26, 2011, 02:23 PM
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Those pictures are just what I need! If I can't fit something I will build custom retracts. By the way, what all up weight are you looking at? I tend to do kit bashing. I always have to be a bit different As my DLG is curing, I am looking at my Windrider BD-J and should I put retracts in it. For the first time in 30 years I have a paved runway available. This has caused me to want a few planes with retracts. The field is actually the old Stone Mountain Airport. (General Lee statue carved into the face http://www.rvforsaleguide.com/images...-picture-2.jpg) They did fly sailplanes out of there. It is 10 miles east of Atlanta.
Thanks,
Ken
Old Jul 27, 2011, 12:03 AM
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The oxen were used due to the fuel shortages of the time
This one is next on the build list once I track down the carbon wing joiners.
Old Jul 27, 2011, 12:27 AM
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Designing something...
@Ken - I don't have a weight on mine yet since I'm not done. We might be able to get Uwe to get us the weight from some of the XII's that have been completed in Germany. I'm thinking that the weight will vary depending on the motor and batter selection.

Brian
Old Jul 27, 2011, 08:44 AM
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How much power is needed to fly this thing? What prop size?
Old Jul 27, 2011, 09:03 AM
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Designing something...
The motor would generally be something in the E-Flite 15 range with a matching folding prop. I'm planing to use a 950KV Exceed RC Rocket motor from Hobbypartz and ~11 x 6 prop. If you're going to go with retracts then this obviously won't work. You'll have to go with a higher KV motor and a smaller prop.

Brian


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