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
Step 1: Printing the plan
- 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
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
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
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
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
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
Use a pencil.
Step 8: Gel-coating
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
Take your time, and wait untill the gel-coat has dried to continue.
Step 10: Resining
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
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
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!