Spars
The spars for the P1 are a glass-foam-glass sandwich shear web, with graphlite unidirectional carbon at the upper and lower corners to provide bending strength and stiffness.
Mold Preparation
The wing was designed around the internal dimentions of off-the-shelf available aluminum U-channel, which provided a spar mold with minimal effort. When the channel was delivered, it was polished with maroon (medium finish) ScotchBrite, first dry and then wet. This provided a smooth surface that was ready for FreKote and layups.
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First Test Section
The first test section was pulled in Sept 2005. It was representative of the spar shear web.
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Spar Strut Attachment Test Section
The second spar test section was made in Feb 2007, and included carbon reinforcement to represent the attachment hardpoints.
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Sparcap Test Section
The third spar test section was also made in Feb 2007, and explored ways to capture the Graphilite sparcaps in the shearweb plies.
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Spar Component Parts
Components were prepared for incorporation into the spar layups.
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Left Spar
The first spar was laid up in mid-February 2007. I got a little ambitious trying to do all 4 shear plies, plus 8 carbon reinforcement plies, all at once - the result was crinkling in the corners where the fibers buckled during vacuum bagging. To repair this, the corner was Dremel-ground back to a smooth 3/8" radius and repair plies were added over the top.
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Right Spar
The second spar was laid up in July 2007.
