Cozy MKIV - Chapter 10

Building the Canard

Start Date: May 30, 1995

canard cores I decided to make the hot wire templates out of 1/16" aluminum. I used 3M spray adhesive #77 to glue the paper templates to the aluminum, and then carefully cut them out to within 1/32" of the line with a bandsaw. I used a 1" belt sander to sand the rest of the shape, and files what I couldn't sand. I made the straight cut templates out of 1/8" masonite. I convinced my wife, Deanie, to assist in the hot-wiring, and we practiced making the straight cuts to get the core trapezoids.

canard cores After a few cuts, we had the cut speed nailed, and proceeded to the actual core cuts with real templates. Turns out my wife is a hot-wire PRO! The most important thing in hot-wiring, IMHO, is fine motor skills; i.e. keep a heavy thing moving slowly at a constant rate. Our cores looked primo! Here they are (after all cuts, including the shear web separation):

shear web Next, I riveted the nutplates onto the shear web 1/8" aluminum inserts (from Brock MFG). After test jigging the rear canard cores vertically in between two 2" x 4" 's, I held everthing in place with nails, micro'ed the left and right cores to the center core, and then used a couple of templates to locate and micro the inserts into the center core. I then masked the bottom of the cores with tape so that epoxy wouldn't drip on it, and glassed the shear web. Here's the finished web:

spar cap Once that was done, I drilled out the 1/4" holes for the alignment dowels and the insert nutplates, jigged the cores with the bottom side up, made sure the front cores fit in place, and then hot glued all the rear cores to the support templates, making sure they were straight and level.

I then micro'ed the front cores to the rear cores, using the dowels for alignment. I micro'ed the spar cap corner radii, as well as any dings and dents in the foam. I layed up the bottom spar cap, staggering and tapering the ends of the 3" wide unidirectional tape. I used 9 layers of the tape, and filled the spar cap trough to the top. The preparation for the layup looked like:

bottom skin Then I glassed the UNI/BID/UNI bottom canard skin. Here's the bottom layup under peel-ply:

full canard view After sanding the bottom skin smooth, I hot glued 1-1/4" PVC drain pipe to the canard elevator recess, mounted five 1" x 4" x 8" wood jigs to the canard, and flipped the whole thing to work on the top of it. I then made the PVC foam hinge mount points, hollowed out spaces for them in the foam, and micro'ed them in place. I also micro'ed the spar cap radii (and dents and dings in the foam). Next, I layed up the top spar cap, using the same technique as for the bottom. Tapering the end cuts of the 3" wide spar cap tape is critical! (As it was for the bottom cap). It allows the end of each layer to blend into the previous layer without ANY bump or joggle. Nat doesn't stress this enough in the plans.

Next, I glassed the UNI/BID/UNI/UNI top skin, and filled the low spots with dry micro. Here's the canard on the bench after glassing the top skin (and applying some micro):

hanging up in
basement Here's the raw glassed and partially micro'ed canard hanging in what will be its resting place for the next year or so (after I finish Chapter 12):

End Date: July 10, 1995


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