150% enlarged WingontheWeb HO-229 - Page 13 - RC Groups
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Nov 15, 2012, 12:29 AM
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turbonut's Avatar
Looks real good..I havent desided if this is the fun part..I am just starting the panels on my Mystere project...
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Nov 15, 2012, 10:01 AM
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I wouldnt call it fun, just necessary. The plus side is, if its going to be molded, you only have to do it all once
Nov 16, 2012, 02:45 AM
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Mooorreee progress

Glued the Bulges and built up the flanges and access panels with tape. Also did the same for the upper engine cowling panel edges for the inner edges. The outer edges can't be done until the flange around the bulge aft of the engine exhaust is done as the flanges only have about 1/16 to 3/32" between each other.

Then mixed up some body filler and spread it around:

Then sanded that down and pulled the tape up:

Then fared the bulges on the outside edges of the engine fairings in:

Then I did the same for the outside flange edges of the engine fairings. I also made up some tape pieces to put in the exhaust cooling vents and placed them down. Then spent a few hours putting down all the 1/64" panel line tape down. For the canopy frame, I used 1/16" tape to define it more.

Then put a light coat of primer down on the panel line tape, let that dry for a bit and then put down a few coats of primer. Gonna flip it over in the Am and do the same to the bottom. Saturday we do parting planes!

I love this part of builds. The detail really makes the airplane really start to come to life. I have pretty much made up my mind that i'm going to flite-metal the metal portions on my HO-229

Nov 16, 2012, 12:23 PM
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turbonut's Avatar
Wow its looking really good...What are you using for primer? it looks very thick
Nov 16, 2012, 12:30 PM
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Its Rustoleum 2 in 1 Filler primer and sander. I picked it up from the local Autzone / Advanced auto
Nov 16, 2012, 06:46 PM
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Lots of sanding today, but finally got the outer wing panels ready for panel lines and the final coat of primer, then color..

Also finished up the center section and wet-sanded it. Its ready to be molded once its waxed and the parting planes built:

The canopy/access hatch (their will only be this one, other than the gear doors) is pretty BIG. I know most people like hatch's so they can install everything easily, but I don't want to ruin the lines of this thing with needless hatch's (this may change). The canopy hatch is larger enough that the fan units can be installed through it, and the batteries can be installed and removed as well. To make routing wires and airlines through the center section easier, i'll pre-install some paper conduit tubes.

Nov 16, 2012, 07:58 PM
right between the batteries
Justo23's Avatar
being kinda new around here... When you say it's a plug, you mean it is not the actual flying model? if so, why paint the wing? or are they the actual flying pieces?

lol sorry to bug ya with noob questions!
Nov 16, 2012, 07:59 PM
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The center section is the plug used to make the mold for composite flying versions. The outer wing panels are actual flying parts.
Nov 17, 2012, 07:30 PM
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Parting Planes are done, plug and planes all waxed.. We are molding tomorrow!!!!!!

So a few have asked about the entire parting plane thing and how to figure out how to position them.. So here's some babble about the mystery of them...

All parting planes do, is give you a surface to build a flange for the mold segments to join together. So there are a few terms we need to know. Positive draft and negative draft. A Positive draft is what you want to keep as it allows you to remove the plug and parts from the mold. Negative draft is bad... In the way that it locks your plug/part into the mold segment to where they are extremely difficult if not impossible to remove.

So positive = good, negative = bad

A good example of a negative draft mold, would be a round cowling with a deep lip at the front that is larger in the center (when viewed from the side) of the cowling than the rear of it, and it only being molded in one piece. The "fat" center and lip would make it nearly impossible to remove the plug/cowl from the mold. If you make it in 2 pieces, it would still be very difficult, as the lip on the front of the cowling would make it difficult to separate the two halves. This is when you would need to do a 3 piece mold. One piece would be the front of the cowling and the lip, then the aft portion of the cowling would be molded in 2 pieces. In order to remove the plug/part, you'd pop the front segment of the mold off, then the two other halves and you have your part.

Now the real fun part. You want your parting planes to be put in a position that will keep a positive draft for the section of the part you are molding. For wings, this is pretty easy, you center them on the leading edge and on the trailing edge. For fuselages, it can become Very complex depending on the shape of the fuselage. The biggest thing to keep in mind, is that you must have a positive draft all of the time, you can get away with a very very very slight negative draft at times, but its not recommended.

That should answer most of the questions, anymore feel free to ask:

Back to the Horten:

First up, i waxed the center section 3 times. Then we took-off to Home Depot to pickup some melamine shelf boards, some clear lexan, rubber furniture bumpers and some insulation foam panels, about $60 in total.

I measured from the table top to the center of the tip rib's trailing edge. Then i took this measurement and subtracted the thickness of the shelf board. This tells me how tall the parting plane supports need to be. So with that measurement, i ripped a bunch of foam strips, then placed them around the center section. They are hot-glued to the table. The side pieces but up against the tip rib to keep the plug from moving side to side, and the front portions but up against the inlet lips:

Then we took the sheets of melamine and cut the front one to go around the leading edge of the wing. Any gaps between the board and the plug where filled with non hardening modeling clay. Then the side pieces were cut to fit between the front one and the wing tubes and the trailing edge. Again, the boards are all hot-glued to the foam supports

For the bat-tail area, since its not entirely straight when viewed from the side, we had to figure out something to do. So we got some .093" lexan plastic and cut it to fit vertically. the plastic flex's to follow the contour of the bat-tail and then foam triangles where hot-glued to the plastic and the table to keep the plastic pressed against the bat-tail.

Here is what the parting planes look like against the leading edge and trailing edge:

And my partner in crime with this project helped as well. All together, this is a full days project for one person, with both of us working on it, we got it done in right about 3 hours:
Nov 17, 2012, 09:28 PM
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turbonut's Avatar
interesting..you have made your parting boards the exact same way I plan for my horten..nice..I do plan to make the intakes a seperate part so I can play with diffrent size intakes..Man that thing is BIG
Nov 17, 2012, 09:30 PM
Registered User
Yea its a biiigg model. the inlets we have are near perfect for the Wemotec Midi Fan inlet ring. All we have to do is cut the inlet rings where they come to a point, and glue them into the inlet, perfect easy inlet radius
Nov 18, 2012, 01:51 PM
Need 4 Speed!
pdawg's Avatar
Great work as usual Invertmast! I like how your molding in the spars for alignment purposes...well thought out!
Latest blog entry: original Y/A F-18 Kit
Nov 18, 2012, 04:39 PM
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Hit a bit of a snag today so the top wont get molded. We were actually very close to applying glass cloth when the epoxy and cotton flock mixture bubbled up. We had to rip if off before it got any hotter, but it was to late, it peeled a big section of paint and body filler out of one of the exhaust indentations, so we just peeled all of the surface coat off.

The affected area is fixed and we will try again on saturday, using a method that i know works
Nov 18, 2012, 04:53 PM
Need 4 Speed!
pdawg's Avatar
That sounds like a pretty hairy situation!!!
Latest blog entry: original Y/A F-18 Kit
Nov 18, 2012, 04:56 PM
Registered User
Yea it sucked, but could of been much worse. It only took about an hour to fix the plug. We will be better off come next weekend, bc i remembered i had the epoxy tooling dough, which is what we should of used in the area that the cotton flock didnt work in.

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