Chapter 10 - Step 1

This step involves the cutting of the canard cores.

Canard Templates June 17, 2001. I made a trip to two different Kinkos to try to make exact copies of the large drawing M-17 (the canard templates). Both attempts failed due to the copies being "distorted". It wasn't a matter of being too big or too small. On the same sheet, one template was too big and another was too small.

What I did next was rough cut M-17 so each template was by iteself. I then scanned it in on my computer and printed it out. It was fine in one direction but too short in the other. I scaled the image in a paint program - just one dimension and printed it again. I did this about 6 times before I found a setting that produced a perfect match. Now I could easily scan in each template, scale the image with the value I calculated, and print it out. I verified each copy to make sure it was correct. I went through this because I didn't want to chance screwing up the original M-17 templates.

Next I used some 3M spray adhesive and stuck the nice copies to some scrap 1/8" masonite. I then cut each template out on a band saw getting within 1/32" of the line. I then grabbed some sanding tools and carefully sanded each. When done I had an A and a perfectly match B (actually I used a mirror copy of A, I didn't use B), I had two perfectly matching Cs, and a lonely D matching nobody else.

Hot Wire Saw June 19, 2001. I borrowed this work of art from my EAA Technical Counselor - Terry Sickler. He obviously put a lot of work into it. It is really light and very easy to use. Cutting cores has gone very well because of this thing.

The first time I went to use it I didn't know how much to turn up the variac. I plugged it in and turned it up to about 70%! In seconds the wire was sagging several inches, glowing bright orange, and smoke was spewing from it. I quickly turned it off. Luckily it was sitting on my bench such that the wire was overhanging the end and wasn't touching anything. I then proceeded to turn it up in small increments until I found the right setting.

Cutting Trapezoid June 19, 2001. The saw is useful for foam up to about 55" so cutting the 64" foam required cuts down the length instead of the width. No big deal since these are really rough cuts anyway. I actually did these myself. Except for the first cut they came out fine.

Canard Center Core June 19, 2001. Here is the canard center core after cutting with the A and B templates. My neighbor Brad helped me out with the complex shapes. Things went very well this first night. We got all three main cores cut with the A and B templates.

My First Oaf Story: Everyone has one of these eventually. The next night Brad and I were to cut the spar cap troughs in the cores. I had read and re-read the plans a dozen times so I knew exactly what we were to do. I decided to cut the troughs in the center core first. I grabbed the C templates, put them in place with the same nail holes, weighted it down, and we cut out some nice troughs. Happy with our work I blistfully grabbed the next core, nailed the two C templates in place and cut the next set of troughs. Another swell job. Grabbed the third core, nailed the two C templates, and made the final set of cuts. We were patting ourselves on our backs about the great job we did. I was so happy with how well the cores came out. Then it hit me! Doh! I'm supposed to use a C and D template on the outer cores. I thought "I'll check with Nat to see if it is OK to use them as is". I figured the only downside is a little extra weight from the thicker spar caps near the tips. On my way in to send the email it then occurred to me the second mistake. I forgot to cut off the 8" outboard core before cutting the trough. Now I realized the cores are no good. I guess I will use the pieces meant for the wing to cut a new set of canard cores - hopefully correctly next time. Bummer.