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Old Apr 30, 2009, 10:04 AM
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Hortn IV

I'm looking for a Horten HIV to build or buy for a local competition. I've seen
and known a few of the "draw your own plans" scratch built ones. Usually they are less than stellar due mostly to poor piloting and home brewed math. With the advent of computer modeling It may be better nowadays.
I have neither the skill, mathematical or computer, nor the time for an undertaking such a serious project. there are plans on ebay occasionally but not from any builders I'v heard of and the last thing I want to do is piffle away three weeks of free time just to find out i got schnookered!!!
The original plans for all the Horten planes are in the Deutches Museum in Munich, If you make an appointment ahead of time you can go over their archives, and even get copies of blueprints made for as little as a dollar a page. (I did my senior thesis on the Krupp gun works and went over to gather some old factory invoices, pictures, and original blueprints)
IT IS AN EXTRAORDINARILY SIMPLE PROCESS!!!!! that pales in comparison to
dealing with the Smithsonian Institute; soooo much red tape!
I refuse to believe there isn't a single set of good plans or a kit
for the Ho IV.
Can anyone point me in the right direction???
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Old Apr 30, 2009, 07:30 PM
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I wish I could, but found similar problems as you have. In the end, I built a chuck glider of around 21" span from pics and drawings online. It was lightly sprayed in a light blue to be similar to the famous test and research model. Thing is, a Horten IV at 21" looks incredibly tiny lol

For what it's worth, I conducted some wind and glide trials out at a local field the other day. The models were all of a similar sizing, most of around 24"-26", were flying wings and all half dozen of them javelin thrown..for comparisons etc. My Horten IV model attained the greatest altitude, of around 70ft approx. It zoomed up a good 10ft more than any other and had one of the best glide ratios. There's nothing there to give it any drag on launch I guess ! Second best launcher was a micro Horten IV of about 8", which gives them a 1 2 from the models flown.
The 'bigger' one was a little nose heavy and didn't like the gusts much, but just to see that slender shape in the air and at height was quite wonderful.
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Old Apr 30, 2009, 10:25 PM
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I did find model measurements at a German site...hopefully of use:
http://www.das-nurfluegelteam.de/
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Old May 01, 2009, 12:07 AM
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Jack Bale had some Hortens but nobody has been selling them since he died. Carlo Godel gave me a plan for a free flight H-IV that's about 2 meters, plenty big enough for modern RC but the airfoils look kind of crude to me. Other than that I haven't seen any plans for Hortens.

--Norm
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Old May 01, 2009, 10:43 AM
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It absolutely boggles my mind that a good one doesn't exist.
Without question the Horten sailplanes are superior to any other!
If i could compile lots of drawings i'm sure i could get something going, but I'd much rather buy scale a working one, and reverse engineer it.
My original intent, beside winning the competition, was to find a good set of drawings have my CAD guy make them digital, send them off to a cutter and sell a parts kit, but this is turning into serious endeavor in a hurry!!
When i was a kid my dad did that with a 98" Hindengurg display models for some local guys.
Well thanks I guess I'll go buy an e-bay set and take my chances???
I'll keep the thread open in case anything develops
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Old May 01, 2009, 11:30 AM
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Check out http://www.albentley-drawings.com/main.htm he I don't know if he has an H-IV but his drawings of the H-IX are outstanding
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Old May 01, 2009, 11:56 AM
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Yep, the Bentley drawings (as they seem shortened to in postings) crop up quite often...good thoughts. Quite a few YouTube videos of scale powered Horten IX's will also mention being derived from those wonderful drawings.

An old looking text page is here: http://www.horten-iv.org/Projekt-Horten-IV.html
I unfortunately read German like I read Double-Dutch, but there is contact information, including telephone number and email at the bottom. Seems they were building a IV.


*edit* I do apologise, you mentioned the museum in your original post
Another idea is to email the guys at the Deutsches Museum.
http://www.deutsches-museum.de/en/fl...t-restoration/
Being as they restored a IV and used technical drawings extensively.
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Old May 01, 2009, 12:14 PM
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Sorry for the double posting too...having a great day huh lol
Reading further into that build site, these guys seem to be working closely with Lufthansa, not a bad name to be associated with. There are progress reports up to the end of 2008, which is good news.
Here's the copied and pasted contact information for someone who may be able to help over at Lufthansa, taken from one of those progress reports:

Pressekontakt: Julia Fischer
Lufthansa Technical Training GmbH
Unterschweinstiege 12
60549 Frankfurt a.M.
Telefon: 069-696 90760
Fax: 069-696 6384
E-Mail: Julia.Fischer@DLH.DE
Internet: www.LTT.de
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Old May 01, 2009, 05:31 PM
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Check this out:

http://www.modellbauparadies.de/inde...lnummer=1-2041
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Old May 02, 2009, 09:25 AM
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I contacted edi's model paradise about his 167.4" of horten wing, and am eagerly waiting for a reply!
The German page recaps the "simplicity" of restoring the iv for the museum due to the widespread availability of information. ha! They are having trouble scratch building the HoIII (apparently none survived in restorable condition so they are building a new one a great expense!) they go on to mention the Smithsonian's unrestored jet fighter and the disappointment in ho slow the project is moving, "not what we had envisaged...(should be) a major priority."
I bought a set of ebay plans for 12 bucks. whats to lose for 12 dollars?
As far as the powered flight models of the HoIX, the most promising I've seen are from the Bell Imel Group. they sell cnc plans that can be sent off to a cutter, plus the availability of retracts!!! my only issue with the ducted IX's are the chincy plastic tubes hanging out of the back. I've only seen teo fly without them, one wa a jet (words can't describe the badass factor!) and other was local I helped out. two fans in those short tubes create a double vortex thas washes over that rear peak. this yaws the plane right...had to trim out without a rudder! The solution i simple counter rotating fans, but I've only seen one.
So now i wait for the plans to arrive

http://www.bellimelgroup.com/products.htm
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Old May 02, 2009, 12:10 PM
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Edi's model paradise sells 2 ARF Ho IV's one has the afore mentioned span (167) and the other is a giant scale 216" beast. they have a half inch steel spar ailerons and drag rudders. the aleron and rudder linkage is built in to the wing, the nos/canopy is made of "heavy working" I'm excited to get a price sheet!

However! it should be noted this model IS NOT scale!!! it is in fact a blown op version of a scale Ho III with a canopy added!
but still 216 inches of Horten!


plywood.http://www.modellbauparadies.de/img/...oss/1-2039.jpg
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Old May 02, 2009, 12:11 PM
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How do i post an image?
[/IMG]http://www.modellbauparadies.de/img/gross/1-2039.jpg
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Old May 02, 2009, 01:04 PM
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Let's see if this works
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Old May 05, 2009, 08:35 PM
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The frst set of plans

Thanks but how do I preform the task?

I bought the $12 ebay plans.
they state no date nor builder, 36" free flight rubberband launch model. no spar, cg is unmarked, and it the airfoils are questionable at best. the plans state a 3/16 washout on the wings (they give the rib # where to stat the twist) and it seems the correct location but insufficient washout. I also received a 96" plan for the same airplane. right now i'm debating whether or not to go all the way with this baby? I'm thinking build and free flight test the little guy. use an arrow shaft for a spar. Then mount a 1/4 inch bolt in the canopy; put a nut on it and adjust it fore and aft until it flies right, mark the cg, and off to the laser cutter for the biggun!

The reason i want to post n img. so bad is;
with no builder,date,company name etc.
these plans have no copywrite!!!!
that's free for everyone!!!!!
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Old May 05, 2009, 10:26 PM
internet gadfly
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Quote:
Originally Posted by Shegal
Thanks but how do I preform the task?

I bought the $12 ebay plans.
they state no date nor builder, 36" free flight rubberband launch model. no spar, cg is unmarked, and it the airfoils are questionable at best. the plans state a 3/16 washout on the wings (they give the rib # where to stat the twist) and it seems the correct location but insufficient washout. I also received a 96" plan for the same airplane. right now i'm debating whether or not to go all the way with this baby? I'm thinking build and free flight test the little guy. use an arrow shaft for a spar. Then mount a 1/4 inch bolt in the canopy; put a nut on it and adjust it fore and aft until it flies right, mark the cg, and off to the laser cutter for the biggun!

The reason i want to post n img. so bad is;
with no builder,date,company name etc.
these plans have no copywrite!!!!
that's free for everyone!!!!!
OK, first things first. To post files on RCG you have two options. From the advanced screen you can use the <insert image> icon at the top of the input box to have a large (and often slow loading) picture show up in your massage. It looks like you had used that but then edited your message some more and accidentally deleted part of the tag. The other way is to scroll down below the input box and us the <manage attachments> button. That will put a nice little thumbnail in the message and can be used for other nongraphical file types too.

The drawing you found on ebay sounds like what I have but this one is 66" (I hadn't actually measured it until a few minutes ago). An arrow shaft may or may not do the job. If it doesn't use the whole depth of the wing you will be losing a lot of potential stiffness and a tube isn't the most efficient shape anyway so it will be heavier than an ideal shape (a box or an I beam) . Also here'sa graphical method to find the CG range of a 'wing with a stability estimate

--Norm
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