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Old Dec 18, 2012, 10:41 AM
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Thanks for the kind remarks Eric

I thought you would be interested to see a photo of the leading edge splice joint. Not perfect, but good enough that it took me a few seconds to see where the joint was! The other wing was better but my camera battery just needs recharging.

Today I plumbed up the tanks and was concerned enough about them bulging to wrap them in carbon bandage tape. As usual I tested the tanks for leaks and found they did bow outwards quite a bit. I must try to fill the tanks slowly, maybe worth putting a restrictor in the fill line.

John
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Old Dec 20, 2012, 05:08 AM
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Started the small fuselage. I made up the formers and engine bearers and loosely assembled to check alignment etc. I have to cut out the hatch for the engine so needed to take this into account when designing the parts.

Should start the balsa planking this afternoon.

John
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Old Dec 20, 2012, 11:34 AM
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This is the fun part! Planking is just a matter of practice and there are a number of things I have learned. Make sure the planking balsa is 1/8 inch so you have plenty of spare material to allow for sanding. Don't make the planks too wide, plane the edges so they are bevelled to suit the plank you are joining to. Don't be in a hurry and make sure the planks are well cramped up into place. Let the glue set before adding more planks.You should avoid any gaps and it saves a lot of work if the planked surface is reasonably free from ridges.

John
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Old Dec 20, 2012, 11:40 AM
Herk
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I love balsa.
What kind of glue are you using? Looks like carpenter's wood glue.

Good stuff, but hard to sand. Do you have a special sanding method? Maybe I should wait for you to tell about that step.

I have always used Ambroid cement for planking. It's pretty strong and sands very well.
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Old Dec 20, 2012, 02:06 PM
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Hero

I use yellow aliphatic glue which is much easier to sand than white wood glue.

John
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Old Dec 21, 2012, 06:21 PM
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Hi John,

great to see that you decided to make the canopy. You won't regret it!

@Herks: I use UHU Hart, which is in combination with balsa great for sanding but hard to get outside Germany...

Cheers,
Andrés
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Old Dec 22, 2012, 04:18 AM
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I have just finished planking one side and nearly completed the second. I have just roughly sanded one side so you can get an idea of how the planking went. As you can see some of the planks particularly in the middle have almost no visible joints, those that are visible are filled with glue. This is a better job than I made of the last plane I planked. I now have to figure out how to make the inlets.

Andres, now you can see how the rear differs from your original design. The holes in the formers are just large enough to pass the jet tube through from the rear and the pipe size is the same as I used on the Arado.

John
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Old Dec 22, 2012, 05:59 AM
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http://www.rcgroups.com/forums/showt...1765224&page=2

Don't know if it's of interest John,but this is a thread about using a balsa stripper to cut bevel edge planks.
Stuart
Should have copied from page 1
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Old Dec 22, 2012, 11:32 AM
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John, I see from your window shelf that you are sporting a new bag of Sig Koverall. Good man! It's a great covering for a high speed model such as this.

Kent
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Old Dec 22, 2012, 12:29 PM
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Kent

I never used Koverall before so it will be interesting to try it. I have some glue that is tacky with heat and I will have a try on a patch before going for it on the plane.

John
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Old Dec 22, 2012, 01:41 PM
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Oooooooooooh, in that case you'll hate it
At least I did the first time I tried it. There IS a learning curve. I had never used a doped on covering before Koverall. It's worth doing a little research on RCG to get a good procedure and then tweaking that procedure to meet your particular skills.

Koverall IS the only covering I use now. When the time comes, I'll post my procedure if you like. My approach is a little different than most.

You must glue it down first. The Sig product Stik-it works great as a heat activated adhesive, but is a little pricey, smelly, toxic, sticky and difficult to work with.

BTW, Sig actually has (had?) a tech support guy, Bob IIRC, who actually knows how to apply Koverall. They couldn't pay this guy enough. Very knowledgeable.

Kent
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Old Dec 22, 2012, 04:01 PM
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Kent

The last time I used a doped on covering was nearly 60 years ago and that was silk. Not afraid to try especially as Koverall will shrink with heat.

John
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Old Dec 23, 2012, 10:14 AM
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What's sixty years when you're having fun.....

Koverall shrinks like mad. That's what I like about it. Make a little square mock up of light balsa, cover it, then shrink with a heat gun. It will distort the balsa like a pretzel.

A big difference between Koverall and silk is how it lays down with just dope. Silk can be worked over curves with just dope and Koverall cannot. It must be glued down.

What I like about Koverall is after it is doped down (nitrate dope), you can sand it. I just let it run wild during the doping, such as at the LE, then after the dope has dried, it cuts and sands nicely. Then another layer of dope to lay down the fuzz.

Kent
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Old Dec 24, 2012, 11:03 AM
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Quote:
Originally Posted by Knoll53 View Post
What's sixty years when you're having fun.....

Koverall shrinks like mad. That's what I like about it. Make a little square mock up of light balsa, cover it, then shrink with a heat gun. It will distort the balsa like a pretzel.

A big difference between Koverall and silk is how it lays down with just dope. Silk can be worked over curves with just dope and Koverall cannot. It must be glued down.

What I like about Koverall is after it is doped down (nitrate dope), you can sand it. I just let it run wild during the doping, such as at the LE, then after the dope has dried, it cuts and sands nicely. Then another layer of dope to lay down the fuzz.

Kent
I have reached the point of playing with the covering. I tried a square of ply with a stain polyurethane that to my eye looks quite nice. I have Oracover heat activated glue. I painted it on the edges of the square and made sure it was set before applying the Koverall and fixed the edges with a hot iron. This worked fine and I then used a hot air gun to tighten the material. I was able to get it tight as a drum without pulling off the glue. Then I applied some clear polyurethane varnish and that seemed to work ok, but I am worried about the Koverall being secured well enough so it will not peel off. The varnish does not seem to have bound the Koverall to the underlying surface as well as I would have hoped.

I guess I need a test with laminating resin or dope.


John
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Old Dec 24, 2012, 11:32 AM
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You may find that glues don't stick well to the polyester Koverall. Nitrate dope is the common attachment method. For me, the initial perimeter gluing, with a heat activated glue, is solely for the purpose of allowing the field to be shrunk tight, then all gets doped down, including the initial gluing.

BTW, I have a suspicion that Koverall may act like peel ply with resin. If it weren't for the very open weave of the fabric, it probably would not stick at all to resin......just a guess.

Let us know what method you come up with.

Kent
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