Rocket construction: Laminated Cardboard Fins
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To ease cutting the fins for optimization purposes, I prepared a sheet
with a drawing program with 6 identical fin shapes, containing square lines.
You can view and download it
here as a 25
KB GIF file (use the right mouse key on the picture, save as ...). This pattern
was copied to coloured paper (160 g/m2), then laminated between
250 micron THICK polyester sheets (each of the 2 sheets is 0,25 mm thick).
Many office or copy shops can do that for you. This gives nice stiff fins.
An option is to soak the cardboard with low viscose cyanacrylate glue
before laminating, to increase stiffness. Then just cut out 3 or 4 fins to the desired size. The blank stripe on the side is cut into 4 small flaps. (On the left pic, I use still another stripe - this particular fin was used for a rocket with a tapered end.) As shown in the right half of the pic, these are folded in a right-left-right-left manner ... |
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... and may be taped to the rocket skirt, which again is taped to
the body.
A very fast method of fin construction. |
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Alternatively the fins can be glued with a flexible glue (I used Sikaflex-252; US citizens use Shoe-Goo or PL Premium) to the rocket body. This glue and the Laminated Cardboard Fins make an unsurpassed combination, since it has immense stability and bending abilities. As this picture shows, the fin (here red) can be bent to 90° to the side without any harm done to the fin nor to the fillet (white - here my 1st test-fillet). It snaps right back to the original position when released. |
