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Wednesday, February 14, 2007


Dont fly these planes in a thunder storm the carbon fibre could attract lightning....... no jokes
On a quest to build strong and light, I tried a slightly different lay-up on wing no 2
These photos show the layup of the centre panel which is made up as follows.

Normal herex cut and sanded for sandwich.
1 x layer 49 gram glass cloth not at 45 degrees
1 x carbon cloth 96 gram at 45 degrees
These form the outer skin.
Inside there is 1 x layer 49 gram glass cloth.

the bottom panel has 7 x 60k tows with 4 x full length then spaced 5 x , 6 x and with 7 x across the centre about 40 cm . The top panel has 2 x more tows full length ending with 10 x across the centre 40 cm. Does this make any sense........well yes the top normally fails first as it is under compression on the winch, the bottom needs less tows as it is under tension.

The stepped layers of tows closely follow the curved load on the wing on its bending moment,
ie. greatest in the middle and less towards the tips , put very simply.
Next I have built a sheer web which holds the top and bottom spars together and or apart depending on what load the wing is undergoing.

This sheer web is made of 1 x 6mm balsa strip (normal grain) glued to this is a layer of 4mm
balsa end grain ( verticle) this resists crushing. This strip is sanded to fit between the skins when the moulds are joined, I have now pulled a carbon sock over this sheer web allowing overlap on the ends. The ends are wet out form a bond to the joiner boxes which are epoxy glued in place not with resin but structurel glue.(Sika-dur works fine)

The rear sheer webs for the flaps are made with balsa that has had a layer of 49gr glass bagged on each side and the cut into a strip , these are bonded in place with resin/flocks/microballons
which is "iced" on using the plastic bag as shown before. Dont forget to glue in hard points in this case ply wood for the wing bolts.
The estimated weight of this panel is 700gr about 180gr lighter than my 1st attempt, and considerably stronger, pop it from the mould tommorrow.

Another view of the STILLETO S in production.

Each time I layup a STILLETO there is a bit of an experiment going on so if you can add to this please dont be afraid to post a comment it would be constuctive and welcome.

See Ya Later.

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