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Friday, February 02, 2007


Work has taken centre stage so glider is now in the wings (get it) Ha , so we chip away with some of the little pieces in the meantime( it is like eating an elephant, one bite at a time)
I have shown some glass / epoxy layup detail , but this is more about each step , I am trying to achieve strength and weight saving in the stabiliser ,as lead in the nose in a ratio of 3 to 1 is required for balance, and this drives up total flying weight.

Photo 1 shows the waxed moulds, sprayed ready for layup( a recent problem of the stripes peeling off in places) may be overcome by lightly sanding the paint with 400 grit and a good clean up of paint dust. Other builders layup epoxy onto the paint the moment it is touch dry , this also aids adhesion . I dont always have enough time so lay up later. The balsa sandwich is light 1 mm cut to shape with space for carbon tows, the leading and trailing edges are champered with a sanding block , do this on a clean ,flat surface gently, the balsa is fragile.

Next I cut the glass cloth at 45 degrees to shape ,in this tailplane, I have 4 x 49gr layers . 1 X Inner and outer sandwich top and bottom, I also cut the carbon tows and some 96gr carbon cloth, which will strengthen the centre section for joiners.

The cloth and components are weighed and come to 39 gr .I think about 20gr of resin will do , so I mix up 10 gr to start. The resin is painted on in spots, with a smallish brush to hold the cloth in place, then using an old credit card or telephone card this is spread evenly, only adding more resin if areas remain dry(white in colour) at no time should the resin be thick enough to look shiny, any excess can be lightly mopped off with paper towel.

The wood goes on after it has been cleaned of all dust, I then wet out the tows , very little resin is needed, in this case I have 3x 12k tows layed 3 to 2 to 1 to the tips and 1 x tow around the leading edge.
Next the second layer of cloth is added and lightly wet out, total resin 10 gr per side, I mix fresh 10 gr resin and repeat the proceedure in the second side. The mould is now prepared for the vacumn bag , which sucks out all the air , this also pulls resin into and through dry areas and holds everything in place while it cures.

The mould and resin would stick inside the bag so a layer of nylon material called peel ply is placed over the layup, it is porous and will allow excess resin to escape , but once cured will peel off( tip peel back parallel to the surface) .
On top off this comes a release film(pink) it has tiny holes in it and allows air out ,and sits between the bag and the peelply. Clear as mud? no really its not that bad once you've had a bit of practise or been on a building group.

Carefully place in the bag , seal with caulking or tape and, pull some vacumn, then visually check for bubbles, creases etc. release the vacumn , rub out faults , realign if required, then apply vacumn and leave until cured. This tailplane will be joined shortly, and if the tubes and sheer webs can be kept light , will weigh around 80 grams , my 1st attempt was a hefty 120gr.

Maybe next week I get a chance to do the wing tip moulds I will take photos.

They say good things come to he who waits, I just want to fly this creation waiting is hard

Keep you posted, and oh yea you are welcome to post a comment , got a good one the other day
thank you.

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