Wing Rib Skin Clamp
The Wing Rib Skin Clamp, which clamps wetted plywood so it dries with a 3mm jog in the plywood skin, is now complete. Wes and I did a quick test with .8mm plywood (twice as thick as the .4mm plywood we will use for the actual rib skins), and it seems to work pretty well.
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| small test piece in Wing Rib Skin Clamp |
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| The 3mm jog (with 5mm radiused edges) is visible here. |
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| The tool opened |
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| The resulting part (after drying in the tool) |
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| The test piece fitted to the jog in the airfoil |
In the actual airfoil, a 2" wide strip of plywood, as long as the chord -- about 1.2 m (47 inches) long for the Root Chord airfoil -- will be put softened at the appropriate location and put into the clamp to form the jog. Cap pieces will be made for both the top and bottom surface of the rib. Then after drying overnight, the plywood will be glued to the top and bottom of the airfoil and either clamped in place or vacuum bagged for drying.
We'll be running tests with different kinds of glue to see what works best and dries the lightest, before making our final choice.
Foam Notch Tests w/ Hot Wire
We did some test cuts with the hot wire to see how small notches (0.5 mm to 3 mm deep) would work to create tick marks on the outer surface of the foam wing rib. These notches will be used to align the spar doubler and trailing edge doubler pieces in the horizontal axis (laser marks on the doublers will be used to align the vertical axis).
Very shallow notches will also be used with a digital code to identify the 35 unique wing and tail ribs, so that at a glance the ribs can be identified after the 6mm ribs have been shaved off the wing rib block on the bandsaw.
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| Notches at the spar location (.375 X chord length). These will be used to align the balsa doublers. |
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| Notch tests |
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| Notches of various shapes from 3mm to 0.5 mm deep |
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