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Tuesday, January 10, 2017

Ch 10 - Canard - Part 7

Flipping the canard (10.1 hrs)

With the bottom of the canard completed, the plans instruct to separate it from the jig, and flip it over in order to start glassing its top surface. Before that could be done though, a new jig would have to be built on top of the canard’s bottom surface (currently facing up) to avoid disturbing its carefully aligned span. 

The new jig should consist of a 130” (3.3 m) long straight pipe1.25” (3.2 cm) diameter fitted to the trailing edge, and four wooden steps bonded to the canard’s bottom.

The straightest longest metal pipe I could find was a few inches short of ideal, but lacking better prospects I went with it anyway, and attached it with Bondo to the trailing edge of the canard.

Plain automotive Bondo

Small dabs of Bondo applied to the trailing edge

Metal pipe attached to the trailing edge

The plans dimensions of the four wooden feet were 1”x4”x8”.

Plans' instructions on how to set up the new jig

I didn’t have a one inch thick board from which to cut them, but I had a leftover 2x4 beam laying around, so I used that instead, and changed the design slightly as well. 

I carved a small foot out of the block to make it sit better on the canard

I took great care to make them as close to identical to each other as possible.

Using fences and stops to help with repeatability

Next, I made a “movable jig” to help me line up all four pieces at the same 2” distance from the leading edge.

The two inches aren't critical, but setting all feet at the same distance will help later.

With this homemade fence, some shims, a level, and a speed square, I positioned the wooden pieces on the bottom of the canard, then used hot glue to set them semi-permanently.

Setting the leading edge distance, and shimming to level.

Making sure the foot is not crooked

To visually check that all the wooden feet ended up at the same level, I once again pulled out the laser and aimed it at their top edges. I figured I could sand any differences down to the laser line, but I lucked out, and all edges lined up on the same plane.

Laser hitting the very top edge of the wooden feet

Same thing on the opposite end the canard

After a big sigh of relief, I pulled out my 8’ level to check the feet once again manually.

Spanning the first set of three wooden feet I detected no rocking, and no gaps with the middle foot.

Middle foot touching the beam, while measuring with two levels.

The second set of wooden feet felt just as solid as the first

Middle foot also touching, and zero leaning.

At this point I had done all I could, and the only thing left was to rip the canard off the former jig and entrust its straightness to the new jig. So I pulled up on the leading edge, which came off the jig without much trouble, and flipped the whole canard over onto the unused part of table, letting it down gently.

Canard is finally off the jig

To my great surprise and relief, the whole ensemble felt solid as a rock, and damage to the foam was minimal. Very satisfied with these results, I put the canard back on the old jig to do a little sanding on bottom surface of the leading edge (I should have thought of this earlier) in preparation for further glassing.

Peel-ply did most of the work for me, but there were a few strands left and a little rough edge in a few spots.

The final step was to sand the leading edge fiberglass to a feather edge.

Feathering the fiberglass edge avoids creating a bump along the leading edge

To accomplish this more precisely, and comfortably, I discarded the old jig, then I stood the canard vertically on the back end of the new jig, and screwed it to the table.

I used foam scraps to support the trailing edge

Four screws secured the whole thing to the table

Using the sanding block I removed the least amount of glass needed to blend the bottom of the canard smoothly into the blue top foam.

In general, when you are comfortable you do a much better job.

Leading edge smoothed

I tried very hard not to touch any of the blue foam with the sanding block

Later I removed the screws, and sat the canard right side up on the table where it would receive a little more preparation before further glassing.

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