Picture of Making a fibre RC flying wing PART 1
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Many years ago I bought a RC wing-styled airplane and learned to fly it the best I could.
I never flew an RC airplane before and I don't have to tell you that my toy went really fast ... into the Guiness Book of Records with the highest crash-rate ever. It flew with high speed against everything you can imagine. Our house, the barn of the neighbours, a passing truck, many trees and, way too much, the ground.
Exit my wing.
This foamy piece of high-tec was definitely not for beginners, I learned. Or, surely not for a crash-pilot like me.
So I took a wise decision.
I decided to start my air-career with more friendly planes and I started to build my own RC flying wing.

Or better: my Yak-Proof flying wing in polyester and glass fibre! I called it the 'Mr. Bluesky project'.

This Instructable starts with the very beginning, many years ago. It will describe the process of building a mold starting from a wood model that ... you have to make also.

All you need:
- a lot of plywood
- saws, plane, sander
- a lot of epoxy
- a few sheets of glass fibre
- a lot of safety gear
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Step 1: Printing the plan

Picture of Printing the plan
I surfed a lot on the net, downloaded a lot of plans, and finally choose a 'combat wing' concept.
- print it to the size you want (I chose A0)
- print each wing-half on a piece of plywood (as thick as possible, the meaning is to profile each wing apart and assembly them at the end)
- print each cross-section (one large and one small) on a blade of steel

Step 2: Cutting the cross-sections

No pictures, sorry.

You printed the two cross-sections of the wings on a steel blade (I took an old saw) and now you'll cut them out with a grinder, and finish them with a sander.
Meaning of all this is that you'll fix them to the wooden wing-halves. The steel blades will serve you as a guide.
Drill two holes in it to fix a few screws.

Step 3: Cutting the wing-halves

Picture of Cutting the wing-halves
Print each wing (a flying wing is just two wings glued together) on a piece of plywood (mine was almost one inch thick).
Cut them out with a saw and fix the steel cross-sections on their side.
You're ready for shaping.

Why making a plywood wing first? Wouldn't it have been a lot easier to make a wing of styrofoam, and use this to make the mold?
Yes, it would have been a lot easier and time-saving. BUT, the hardening of polyester is an exothermic reaction. It produces heat. The heat will melt your foam wing and force you to do the shaping all over again.

Step 4: Shaping

Picture of Shaping
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Planing, and a lot, A LOT, of sanding...
Take your time, it's all about precision.
Once one wing is done, fix the steel cross-sections to the other wing and shape this one.

Step 5: Assembly

Picture of Assembly
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Assembly the two profiled wings and check out for errors.
Sand where necessary or fill up (with wood-paste or epoxy) to sand again.
Protect your model with a varnish coating or epoxy.
Sand it again. As smooth as possible.

Now you finally got your wooden wing, congratulations! It's a beautiful piece a artwork that will serve as... nothing. It's just a model to make another one. You'll copy this to a fibre version.

Step 6: Making the frame

Picture of Making the frame
You'll make a mold from this model. So you have to make an UP-side and a DOWN-side of polyester.
The best way to do this is to make a wooden frame of plywood.
Make sure the frame touches the model exactly on the sharp edges of the model.
Fix the model in the frame with some silicone.

Step 7: Waxing

Picture of Waxing
Wax frame and model with a few layers of special wax 'cire de demoulage'. This will avoid the polyester to stick to your model and ruin everything.
Use a pencil.

Step 8: Gel-coating

Picture of Gel-coating
Once the wax is dry, it's time to put the gel-coat (gel-coat is a white resin often used as first layer, it's not strictly necessary).
But it's oh so beautiful! ;-)
No need to tell to wear gloves and a carbon-filtered mask. This stuff is toxic.
Work in a well-ventilated area or outside.
Clean your gear with aceton. Or use 'one-use' pencils (I bought a box of 100 to be safe...).

Step 9: First layer of glass fibre

Picture of First layer of glass fibre
When the gel coat is a bit sticky yet, you can put the first layer of glass fibre. Don't take it too heavy (I took 160gr/m2).
Take your time, and wait untill the gel-coat has dried to continue.

Step 10: Resining

Picture of Resining
Prepare the polyester (read the notice), add 2 a 3 % of MEPK-hardener and poor in on the fibre. Use a pencil to spread it out.
How much? Just enough to penetrate the fibre.
Wait until it's dry, and put a second layer of fibre.
Pooring resin again! Use a roller to remove air-bells.

I put a third layer of really thick swimming pool fibre to finish, making this half really solid.

Step 11: Doing the other half

Once the whole thing is dry, it's time to 'demoulate' aka splitting mold & model. Nice!!!
Remove the model from it's frame, remove the silicone and place it in it's mold-bed (like a mummy in it's sarcophagus).
Put silicone around the model to seal model & mold together.

Now you'll do the whole process over again: waxing, gel-coating, multiple layers of resin & glass-fibre and so on.

Finally you will be paid with two beautiful halves of your model!

Step 12: Side-step: the polyurethane-wing

Picture of Side-step: the polyurethane-wing
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To know if it was technically possible to make a foam wing I waxed the two halves, put them together and fixed the whole thing with screws a bolts.

To do what? To fill it up with expansive polyurethane-foam (that time not forbidden yet) and to see if it was possible to make a foam wing with that material.

Bad idea, don't do this again!

After one day the foam still wasn't solidified and since I refused to drill air-holes in the mold I abandoned the experiment and cleaned the whole messy stuff up...

Next Instructable: PART 2 - the making of Mr. Bluesky!
Rototiller1 year ago
It may not have worked for injecting expansive foam into your mold, but you do have a beautiful mold if you wanted to make a fiberglass zagi or even a carbon fiber zagi?

I have never seen a fiberglass or carbon fiber zagi, talk about indestructible!
rimar20002 years ago
Very nice aircraft, good work.
dawg0653 years ago
Was this inspired by the germ Horton flying wing?I know the americans had one also after ww2.
bricobart (author)  dawg0653 years ago
To be honest, it was inspired by the Northrop YB-49 “Flying Wing” - a US bomber who never made it to the battle fields.
Here's more: http://www.txchnologist.com/2011/gallery-the-world-that-wasn%E2%80%99t-visions-of-the-aviation-future/flying-wing
Actually I'm making the body, and depending it's weight (glass fibre & polyester are not the lightest materials) I'll choose the type of engine (one motor or two, we'll see).