|Dec 14, 2012, 08:13 AM|
Yes, I used PVA, after some layers of release wax.
It left some small scratches on the surface, because I did not use an airbrush to spray the PVA. I used a piece of cotton tissue. But I believe that that those scratches will be easily removed in the sand process.
On the fuselage mold, I will use an airbrush for sure.
|Dec 21, 2012, 10:23 AM|
It is polyester based and it was really easy to polish.
I used 320, 400, 1500 and finally 2000 grit sand paper.
Also applied some coats of release wax.
Next week I will have some days off duty and I think that will make the first tail.
I believe that the layup will be hollow, with an external layer of carbon fiber and an internal layer of fiberglass. I want the carbon fiber to be exposed just to see how it looks. :-)
For the hinges, will use Kevlar.
Hope you enjoy!
|Dec 22, 2012, 01:49 PM|
Finally i found the time to make the video tutorial showing the construction of the tail mold.
It is narrated by me in Portuguese, but I think the images speak for themselves.
Maybe I will put subtitles on it.
Hope you enjoy!
|Dec 22, 2012, 08:49 PM|
Thanks for the video Charles. I liked how you put the thin layer of glass into the tooling coat. Was your mould poliester, or just the tooling coat?
|Dec 30, 2012, 06:05 AM|
Everything on this mold is poliester based, including the tooling coat!
I made the first lamination of the tail.
Was a lot of work because my lack of practice.
I will do several tests with this tail, which is small and so I do not spend much material.
In this first lamination used a layer of fiberglass on the outside and one layer of carbon inside. The glass fiber was nearly transparent.
I gave up the idea of letting the carbon out, because the mesh is very loose. I only found a 200g/m² carbon tissue here in Brazil.
As you can see in the photo, there are some air bubbles, especially in the corners at the bottom. To avoid this I will use epoxy microspheres next time.
What has really difficult was how to join the two halves. As the piece is very thin, do not know the best way to do it. I let the leftover fabric in the mold because I found it very difficult to sand or cut. Then I epoxy in the corners and closed.
I think the best way will be to try to make a template to cut the fabric exactly the size of the mold. I will test it next lamination.
This is weighing 47g. I think it is very heavy. Maybe used too much resin and carbon.
I'm also thinking about using a 1mm balsa for reinforcement.
I appreciate comments, especially about a good way to make the joints.
|Dec 30, 2012, 04:40 PM|
place your fg skin in the mold with your templates, moving the fg to the edge of the mold. Then let the epoxy or polyester get tacky so the skin does not move then wet your carbon out on the bench oversized slightly to your templates, then fold your wax paper over your fabric and hard roll it really well at 45 degrees. Then light spray some 3m 77 on your poster board template and stick to the wax paper and cut your carbon out to size after it has been rolled.
Then place in mold, brushing it in the corners nicely.
Then mix up some milled fibers/cabosil/cotton flock 50/50 so it is sticky and place on both halves of the edge of the fabric all the way around so it is standing above the mold, should not sag.
Then close your mold and clamp.
May help- that is how I would do it.
Nice work BTW.
|Dec 30, 2012, 04:59 PM|
Hey Charles, really nice work for your first go! I would definitely use some 1mm balsa as a skin core, and also a carbon tow spar cap. You can make a light and strong tail with a layup of, from the outside in- 1x2oz fg/ 1mm balsa/ 1x2oz fg. This will be light and the balsa coregives the skin good stiffness. For your template, lay masking tape into the mould to line up with the edges, then peel it all out as one piece, and lay it flat- this is now a good template for your fabric, I make mine out of thin ply wood.
|Jan 02, 2013, 03:07 PM|
Thank you Doug and Josh for all those information!
I tried to make the hinges and found it very easy.
I did it with Kevlar.
On the next layup, will use balsa and only spars of carbon!
Next week I will be on vacation and I hope to finish all the molds and make the first prototype.
Thanks for all your help!
|Jan 02, 2013, 04:05 PM|
Congrats Charles......hard to beat Kevlar hinges, some people find them hard.
I think there so quick and easy.
Looking forward to seeing the plane flying at 200mph..
|Jan 02, 2013, 06:15 PM|
Nice work Charles. I reckon whatever my next project will be, it will be a small size one like this, as they are nearly as fast, more durable and about ten times quicker and easier to build! Keep it up mate!
|Jan 04, 2013, 11:49 AM|
I will be happy with 200 Km/h. :-)
I think that my legs will shake a lot on the maiden flight!
Today I started to make some details on the fuselage. Next week I will start the molds.
For cooling the engine, I am going to make two intake, in the NACA´s style.
As it is very difficult to make these small intakes, I had the idea to cast it in gelcoat and then make the other one.
I have never done that, I hope it works.
|Jan 05, 2013, 03:58 PM|
Make the main mold and thinking about the seam
The next few days I hope to start building the main mold.
The wing and fuselage will you be a single piece.
It's a big mold.
I have some doubt on how to make the seam.
Do you have any advice on this issue?
On the fuselage part, I think that will make one half of the mold and then make a template along the fuselagem about 10mm height. The idea is to use this template to make an overlap on the layup. I also think that will move this template about 1mm inside the fuselage to be possible to join the two halves.
I know that would be better express hths ideas with a drawing, but I am away from a computer. Just using my tablet and waiting for the next flight.
On monday will be on vacation.
I appreciate any help!
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