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Old Aug 02, 2011, 02:02 PM
Sane til the lift starts!
kpeevyhouse's Avatar
Laguna Beach, CA
Joined Jun 2008
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Time to get the elevator joiner rod hooked up. For a plane of this size, I would normally use some flat brass plate, drill a hole, slide it onto the rod, and solder it in place. This is acceptable for lightweight planes smaller than 48", if you are good at soldering. Otherwise you'll risk having the solder joint fail on a hard landing. Since this plane is being built for somebody else, I'm making it bullet proof. I'm making two separate rods, one for each elevator half, and they will get joined in the middle.

Take your time to make good straight bends, with matching angles. I'd normally use some brass tube to slide over the two rods, crimp, then solder. But I don't have any brass tubing that's big enough, so I'll improvise. Be sure to sand the music wire now, so that you'll get a good solder joint without contamination.

I flattened one end of the brass rod, which is what the clevis will attach to. Drill a 1/16" hole in the flattened end to receive the clevis pin. Slide the tube onto the post of one of the rods, and crimp it with some pliers. Then I took some electrical wire, stripped off the insulation, and took some copper strands to wind around the posts, binding them together. I held everything in place against a metal ruler, to ensure that the two rods are lined up correctly. I applied a bit of flux, and used an 80-watt iron to apply the silver solder. Sorry, I couldn't take pictures while soldering. But you can see the before & after pictures to see what I did.

Now let's hope it fits! I just eyeballed the fuselage where the elevator goes, and guessed at the dimensions of the rod and length of the brass tube. I'll find out later on if I made the brass horn too long, in which case I'll need to make another joiner rod assembly.

-Keith
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Old Aug 02, 2011, 02:05 PM
Sane til the lift starts!
kpeevyhouse's Avatar
Laguna Beach, CA
Joined Jun 2008
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So... that's where I'm at right now. Today I'm going to get the fuse ready for mounting the wings, and then I'll have to wait until tomorrow when the epoxy is cured before mounting the tail and gluing the wings on permanently.

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Old Aug 02, 2011, 03:05 PM
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codezilla's Avatar
Chino Hills, CA
Joined Feb 2003
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Quote:
Originally Posted by kpeevyhouse View Post
So... that's where I'm at right now. Today I'm going to get the fuse ready for mounting the wings, and then I'll have to wait until tomorrow when the epoxy is cured before mounting the tail and gluing the wings on permanently.

Cool. I was curious how you mount the tails, especially with internal elevator linkage.

Excellent thread!!!

Adrian
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Old Aug 02, 2011, 03:34 PM
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ian murdock's Avatar
United States, NV, Carson City
Joined Jan 2007
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I have some what o a question for you guys that have built a glass wing or bagged a wing. the question is I have the material for the bag, some 1oz. glass and some west systems resin, but what should I use peal ply or Mylar for the wings of the macchi so that the bag doesn't stick to the bag? Also were can I buy a pump and the wicking material?
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Old Aug 02, 2011, 04:15 PM
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Tick Point's Avatar
Joined Mar 2008
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Ian; 1oz of glass on foam isn't enough, I think you need to add up to 10oz or more for a wing. (10 layers of 1 oz, too many layers) Keith recommended 3 layers of 3oz plus finish cloth (review the log, maybe it was 5 oz. cloth). Maybe you're sheeting with wood, then glassing?
Peel ply will wick resin from the mylar taco and will peel away from the bag leaving little resin on the bag. Peel ply is sold as sport nylon at the fabric store ("Joanns" here)
Release film (from ACP) can be used as a barrier between the gooey perimeter of the mylars and your bag (optional).
If resin gets on your bag, the resin does pick off, but it's a hassle. That's been my experience with ACP's bagging material.
I have never bagged without 14mil mylars, I am a little confused with the questions but offer 2 cents, here.
dave
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Old Aug 02, 2011, 04:24 PM
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ACP sells an entire starter kit for about $200 (no pump). I had a pump given to me from someone with connections. The kit had wax, bags, hoses, nipples, vacuum reservoir, mylar, release film, peel ply, batting. Your pump needs to reach 13 to 15 psi.
dave
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Old Aug 02, 2011, 04:40 PM
Sane til the lift starts!
kpeevyhouse's Avatar
Laguna Beach, CA
Joined Jun 2008
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Ian,

Are you planning on sheeting the wings with ply or balsa first, or will you be bagging the glass directly on the foam? That will determine what weight of glass to use and how many layers.

Regardless, you should always use mylars (14mil or 10mil thickness). The mylar is cut to the same outline as the wing, and will be in direct contact with the fiberglass. After the resin cures, you peel the mylar off, and you're left with a very smooth surface on the fiberglass. I also like to use peel ply and paper towels outside of the mylar, because it helps soak up any resin that seeps out, and prevents it from sticking to the inside of the vacuum bag.

Peel ply can be used instead of mylar, but that creates a LOT of extra work for you. It will not give a smooth surface (almost like fine sandpaper), and any wrinkles or waviness in the vacuum bag will be transferred to the fiberglass. You'll need to do a whole lot of filling and sanding to get the wing surface nice and smooth and level.

ACP is a good one-stop shop for all your bagging needs, although you can find stuff cheaper on eBay if you're patient and don't mind ordering from a bunch of different people. http://www.acp-composites.com/home.php

Pumps can be expensive if you buy them new. Used ones sometimes come up for sale on RCG, like these: http://www.rcgroups.com/forums/showthread.php?t=1478475

Go way back to post #25 in this thread, which is where I began the bagging process and showed all the pictures. Hopefully it will become clearer after seeing those.

-Keith
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Old Aug 02, 2011, 04:49 PM
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United States, NV, Carson City
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Thanks you Keith, I have already skinned the wings in 1/64 ply and installed the leading edge and tips.
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Old Aug 02, 2011, 04:55 PM
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United States, NV, Carson City
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Have you guys used the the EZ-Vac Bagging system here.

http://www.acp-composites.com/home.php?cat=4732
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Old Aug 02, 2011, 06:59 PM
Sane til the lift starts!
kpeevyhouse's Avatar
Laguna Beach, CA
Joined Jun 2008
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Cool Ian, you're getting there! Since you've already skinned the wings, you just need to decide how much additional strength you'll need. You could easily get away with two layers of that 1oz, alternating bias, if all you want is an easily paintable surface. If you're going for a lead sled and need more strength, then just add more layers of the 1oz. However, it'd be much easier to do one layer 4-6oz and and one layer of 1oz.

I've never used that EZ-Vac, nor do I know anybody who has. It runs continuously, and only pulls 8" Hg maximum. Will it work for your purposes? Sure. But if you're planning on doing more bagging after this, you could spend a bit more and get a much better setup.

See if you can borrow somebody else's vacuum setup, while you keep your eyes peeled on the For Sale section.


One other alternative is to just Solartex the wings after you join the two halves together. It will be plenty strong enough with just the ply, without glassing it. Well, you'll still need to wrap glass around the center joint, but you don't need to vacuum bag that.
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Old Aug 02, 2011, 07:57 PM
Sane til the lift starts!
kpeevyhouse's Avatar
Laguna Beach, CA
Joined Jun 2008
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I just got the wings "pre-mounted" to the fuse. I'm mounting the wings in two steps due to the small size of the plane and the large size of my fingers, the internal linkage, the stab is mounted mid-fuse, and the wing saddle doesn't perfectly match the wing (the mold wasn't designed for a lead sled wing). I hope it makes sense once you see the pics.

I start by putting the fuse on the wing, and getting it perfectly centered and perpendicular. We have this huge cutting mat with grid lines on it, which makes this very easy to do. If you don't have such a mat, then break out the rulers and measuring tapes and get it all lined up. Use a Sharpie to draw the outline of the saddle onto the top of the wing.

Wrap some packing tape (I used Zagi tape) onto the wing, wrapping it around to the bottom of the wing. Be sure the tape extends out past the lines you just drew. I also packed some more clay into the base of the torque rods, just in case some epoxy gets in there. Wax up the tape and buff it off. Apply another light coat and leave it on without buffing. The wax isn't strictly necessary, but I don't like to fight the plane to get the wings off.

Grab some 100-120 grit sandpaper, and scuff up the entire wing saddle area. You want to give the epoxy something to grab onto.

Mix up a small batch of epoxy and cabosil. You can do this with 5-minute epoxy if you're feeling lucky or skillful. I don't, so I use West Systems for the long working time. Cabosil is much better than microballoons for this application, since it isn't as brittle. Spread a small bead of the splooge onto the entire wing saddle, but try to keep it away from the outer edges.

Carefully place the fuse onto the wing, doing your best to keep it lined up with the lines that you drew on the wing. Slowly press the fuse down harder and harder until it's all the way down onto the wing. Look down the nose of the plane, just to make sure that the wings look level to the fuse. If any splooge squeezes out from the saddle, just gently wipe it off with a finger or paper towels.

Break out the rulers one more time, just to be sure that the wing is still centered and perpendicular to the fuse. Adjust if needed, otherwise set it aside and do not touch it until the epoxy cures.

Tomorrow, I will remove the wing, and the saddle will be perfectly shaped to the upper wing surface. The wing will basically snap solidly into place at that point, and I'll be able to use it to set the incidence on the tail when I cut out its slot.


If I had easier access to the tail, then I would have skipped the tape and this splooge would permanently glue the wing on. With this method, I'll have much easier access to work with the elevator pushrod.

-Keith
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Old Aug 02, 2011, 08:10 PM
Sane til the lift starts!
kpeevyhouse's Avatar
Laguna Beach, CA
Joined Jun 2008
10,198 Posts
Here's the tip of the day:

Do you ever have trouble getting epoxy or a splooge mixture exactly where you want it, in the quantity that you want? My solution is to make little disposable pastry bags.

I get some super cheap sandwich bags, the non-Ziploc kind. Lay it between two pieces of parchment paper, or masking paper. Place it on top of some newspaper for a bit of cushioning. Heat up your Monokote iron to about 300F. Use the sharp edge of the tip of the iron, and draw some crossed lines on the paper. The heat will weld the layers of plastic together, and they can be peeled up from the rest of the bag. Voila! Instant miniature pastry bag! Now just fill it with splooge, cut off the tip, and squeeze out a perfect bead.

You can make any size that you want, and you can cut off the tip to any size depending on how big a bead you want to be dispensed. You can make it long and skinny to get into hard-to-reach spots.

Give it a try! You'll be glad you did. You might need to experiment a little bit with the temperature, speed and pressure of the iron to get good results.

-Keith
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Old Aug 02, 2011, 09:00 PM
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Torrance,Ca
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My mini-mac is coming together. fillets, hatch clip, servo install, prime, paint...etc. I thought I was almost done...
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Old Aug 03, 2011, 02:13 AM
Sane til the lift starts!
kpeevyhouse's Avatar
Laguna Beach, CA
Joined Jun 2008
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Originally Posted by RobCas View Post
My mini-mac is coming together. fillets, hatch clip, servo install, prime, paint...etc. I thought I was almost done...
You ARE almost done, Robert. The only thing in that list that's required is the servo installation. I've tossed many naked planes off the hill.
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Old Aug 03, 2011, 06:01 PM
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Torrance,Ca
Joined Mar 2006
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I need a soldering tutorial, I always have difficulty making the elevator rods. will probably use low profile wing servo for ailerons.
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