Hello ensemble,
It is sometime now I'm developing planes, mostly gliders, to suit my personal taste.
Out of curiosity I started to use some new materials to learn something new.
As a first attempt I did build two fuselages for a plank, called Trisel.
Those are respectively prototypes #5 and #6.
The first fuselage is done in Flax fabric (Eco_Trisel), two 220g/m² layers and a third one on the nose.
The result is a very stiff, hard and heavy fuselage, probably well suited for slope and hard use.
The material is thick and resin hungry, 1.5-2 times the amount needed for fiberglass.
I leaved the surface natural for show purpose, but a layer of transparent gelcoat revealed to be mandatory. The fabric is so hungry that it seems always dry and there are several pinholes.
The second fuselage is done in basalt fabric (therefore the name: Volcanic_Trisel).
It is composed from a 110g/m² plain, 220g/m² twill and a third layer of 220g/m² on a 45° bias.
This one is very thin instead, the lighter of all six prototypes, stiff enough. Not comparable to Flax, but almost as fiberglass or even better, considering it is really thin and light.
This fabric wets very well and epoxy usage was about 2/3 of a fiberglass one and 1/3 of the Flax one.
Weight is 100g, vs. 120-130g of fiberglass and 160 (!) of Flax.
Next step could be using vegetal based epoxy =;D
Best regards,
Ric
Comments
I've dreamed of making a molded plane from pulp. It's good enough for eggs and electronics, so why not a small RC plane. Ever try to crush an egg carton?
Thanks all for the comments!
About flax, you can't imagine how stiff it is. The advantage is that it is not so fragile as carbon fiber, it will not crumble. In fact it is so hard to cut, I destroyed my hands to cut the excess in the mould, *with good, suited tools*.
Harder to cut than Kevlar. About wetting it wets so well that it will absorb loads of resin. I never read on specs about oil presence or issues. Anyway it is made from the stem not from seeds.
An issue could be humidity instead: it tends do absorb water. A recommendation is to heat it at 110°C for some time to dry it before use.
About basalt, an advantage is that it is fire resistant. I bet in short time RC jets will be in basalt =;D
Advantages for both?
Non carcirogen, non petroleum based, non toxic, not so expensive as carbon.
A little tricky to work, but not so difficult at the end. Nice aspect.
... an alternative!
Ric
both thumbs up!
cheibe guet.
Hi Rick,
That looks nice.
New materials. Interesting.
All the best,
Kees
There was a disposable drop tank in WWII made out of shredded paper and glue. It held up long enough to fly a mission and drop it when empty. It was way cheap compared to scarce metal.
I've done some experimenting with fiberglass and polyurethane glue. It's not too tricky, light, and strong enough. Here's a shot of the pod I made that way. I painted the molds first and then put a very thin layer of GG over that and then the GG wet out fiberglass cloth.
Not so much interested in the Flax, but the basalt based stuff seems very interesting.
I would think that one of the problems with flax and other organic materials might be the presence of natural oils which could prevent wetting and decrease strength or produce delamination.