Upper Skin

Step 6 INSTALLING HARD FOAM BLOCK FOR ELEVATOR HINGES, THE UPPER SPAR CAP AND THE UPPER SKIN

Once I was ready to start building the jigs to turn the canard over, given that I had peel plied the entire bottom of the canard, I decided to remove the peel ply only from the front 2" vice the whole bottom. I am hoping this way I can peel ply off the bondo blobs and will end up having an easier time cleaning up the bottom once it does get removed from the jigs.

Here's a close up shot of the process of sanding the front of the leading edge to a knife edge. I used 36 grit and it made quick work of this step. Be careful here, though, it's easy to start sanding foam before you realize it. I ran my finger from the foam onto the glass many time to feel the bump get smaller and start to disappear.

You can see the small blocks I cut to allow the blocks to sit level. The plans called for a 1 1/4" piece of PVC, but I had a piece of 1 1/2" so I went ahead and used it. If you look at the next step you'll see it made leveling the jigs a little easier.

Once the bondoing of jigs started. the wood blocks made this a little easier. I was able to slide the block, fore and aft (after a glob of bondo was put on it to stick it in place) to get the Smart Tool to read 0.0

After sliding the block to where the level read 0.0, I let the bondo cure. This should ensure that the jigs are properly aligned. My Smart Tool is built into a 4' level, when I have small jobs like this to do I pull it out of the level and use it by itself. It uses a 9 volt battery for power that's mounted in one of the end of the level. It's easy to pull that out also and leave it laying close by as you work. You can see the wires that hook to it in this picture.

The plans next tell you to bondo the supports to the table - I held off on that a bit. I thought it would be easier to cut off the fish tail and shape the trailing edge with that edge facing the edge of the table than away from you (I actually flipped it back and forth a couple of times.)

Next step was to sand the fish tail off. I used a hack saw blade, with teeth oriented towards me. Left a little more foam than was needed so I could plane and sand it down to shape properly. I also had a little trouble getting the hack saw blade through the micro and epoxy joints between the sections.

Once I cut off the bulk of the fish tail with the hacksaw blade, I used a Stanley Shur-form (sp?) plane to shave it down to size. This tool works great for foam shaping like this, removes the foam in a predictable manner, but slowly and steadily. I checked the shape with my top canard template frequently to make sure I didn't shave the foam down too far.

This thing is starting to look like an airfoil! With the fish tail cut off and the top shaved and sanded, it's starting to look pretty sleek. Next step was to remove the peel ply under the little sliver of foam on the trailing edge to make the trailing edge ready for the top layup.

Here's a shot of the top template laid over the canard after the peel ply has been removed. You can see that there is a bit of a step on the trailing edge, but other than that, the shape is just right. I'm not sure if the bottom template is a bit off or not (can't be, the templates were right on plan and the foam cut pretty well) but other than the step things are lining up and shaping up pretty good. A couple of other builders have had this step occur, I read in one place that this is how the elevators turn out. Might need to read that part of the plans to see how things are handled there.

I also had the canard on the table trailing edge towards me in this step, given that I have not yet bondoed it to the jig table. I figured this was fine since you're not too worried about twist until you do the spar cap and top skin layups.

After the PVC foam inserts were installed, I leveled the canard using the upper surface template and my digital level out of its 48" frame. You can see some small blue shims on the front of the board holding the canard up off of the jig table. I used some "demo" credit cards that came in the mail, cut into small pieces, as shims. I only was a couple of tenths of a degree from level so it leveled up to 0.0 pretty easily.

Once the canard was checked to have no twist, I did the tape and mask job with some plastic. Not wanting to make the same mistake I made in the bottom spar cap (follow this link to see how stupic I was...) I kept reminding myself to remove this stuff after the layup was done. It looked so nice all taped and masked I couldn't resist taking a picture. You can see the small micro fillet in the front corner where I filled in with micro (because of the rounded edge of the corner of the shear web) to avoid filling that corner up with spar cap tape and heavy epoxy.

The lower spar cap took me about 4 and a half hours - this one, even though it was more layers (mine took 8 layers, although #7 and #8 were pretty short end to end) took me about 3 and a half. Here's why - I had already done this once! My wife Kelly decided to take a bunch of pictures of me doing this step so I will do a photo step by step of removing the cross thread. In this picture, I'm cutting the colored thread or tie thread and the cross threads in the middle.

Next, using tweezers, I grab one end of the colored/tie thread - or cross thread -

and then pull the cross thread out of the end of the layer of spar cap tape. I did this before I wet out the layer, although the extra epoxy from the layer below helps it stick and prevents the layer from sliding as you pull out the tie and cross threads.

The cross threads, after being cut in the middle, pull out from the end rather nicely. Pull them out with a hand over hand motion. You end up with very little disturbance in the spar tape and then you can wet out/stipple/squeegee until the layer's completely wet out. Repeat until the channel is full and voila! One nicely done spar cap!

Here's a shot of the spar cap, channel nice and full, after removing the tape and masking plastic like you are supposed to. It turned out pretty nice, I must say. Note the small bulges where the lift tab bolts had you carve out a bit of the foam from the leading edge piece. I microed in there a bit, but, you still end up with a wider spot that the spar cap tape fills in.

Put on some peel ply and let it cure. I realized, almost too late, that I was just about out of peel ply. I had a 63" piece about 8 1/2 inches wide - you can see it was just enough - whew! I cut it exactly in half and had just enough to cover the entire spar cap with just about an inch or two to spare on either end. For the record, the spar cap is about 126" long - peel ply comes in 63" rolls - what's 63 x 2? 126... someone was watching out for me on that one...

Once I was ready to do the top skin layup, I sanded the bumps and lumps off of the canard top spar cap layup. I also realized I needed to install the antennas (NAV and glideslope) so I got out the Jim Weir kit to make sure I put on the right ones and cut them to the right length.

I also needed to get my DAR to inspect my work before I proceeded. My son Matthew, on Dad's hip so he can see over table, said my work was acceptable and allowed me to proceed to the next step. He did have some questions about my main landing gear (that's what his pointing at) but I addressed those without incident.

Make sure you remember to put your ferrite toroids on before you solder the foil elements on. I soldered the glideslope elements on, before I installed the toroids, and had to then put them on from the other end of a pretty long piece of RG-58. Took a few minutes, but, I avoided re-soldering the antenna together.

Here's a close up of me soldering (the digital camera has a timer for "action shots" (see the smoke from the solder) the antenna elements to the center and braid of the RG-58. I use a piece of 1/4" aluminum as a heat sink. Keeps the foils from burning the paper backing and keeps me from messing up my work bench, too. I like to do these away from the airplane to make sure they're done right. Some of the foil elements are pretty long, too (the one for NAV is 22.8", each element) and doing this on the workbench allows me to lay them out straight to get a nice solder joint.

I routed a small channel just aft of the spar cap for the coax. I used my router with a 1/4" straight bit, set 1/4" deep (the coax is a little over 3/16" in diameter) with a spline sanding board squeeze clamped to the top of the canard as a guide for the router.

Here's the glideslope antenna laid out with the coax in its channel. I free-hand routed a channel for the coax to curve and intersect with the point of the V of the antenna, and, used a Dremel to make a larger cut out for the toroids and solder joints. The foil elements are laid out in their proper orientation. I will fix the coax into the channel with CA glue, then micro over it to fill the slot back in. I usually use 5-minute eopxy to pot in/fix the toroids, spaced with 1/4" scrap pieces of foam, as well as the soldered ends of the foil elements. The foil has a sticky back, once I'm completely ready for the layup I'll peel the backing and stick the foil elements down just before I apply micro and glass.

Here's the NAV antenna, with much longer elements, almost ready for the next layup. Again, I free-hand routed a channel for the coax and toroids. This antenna will curve around the leading edge just a bit, but I won't have it wrap beyond to the other side. I am worried if I do that the antenna will break - with some of it in compression and some of it in tension, and the element fixed in the glass layup and unable to stretch or move.

Here's a shot of the entire top of the canard with both antennas in place and their coax run in the channel to the middle of the canard. I drilled two holes, just to the left of center, down through the canard, aft of the spar caps, for the coax to run through. I had to make these holes left of center because there is a jig holding the canard exactly in the center. This part of the canard should be inside the fuselage, however, so no one will be able to see it. I also cut the channels a little deeper near the holes, then really deep just next to the holes to avoid a sharp bend in the coax as it turned down to exit the canard.

Once the antennas were mounted, I clamped some short 1" x 2" boards to the edge of the table and hung some plastic from them.

I laid plastic on the trailing edge as well, I knew the next layup was going to be messy.

Here's the canard top after doing the top skin. You can still see the antennas, this side is NAV 1, through the layups. I will need to knife trim this once it cures for a couple of hours.

Here's a shot of the GS antenna end after doing the top skin and adding peel ply. This layup altogether took about 3 hours and 15 minutes. Kelly helped me with most of it. The only real hard part is the layers that wrap around under the leading edge. Make sure you use pieces of glass in a sequence that makes sense - that is - use the layers with a finished edge rather than the ones with tape on them. It's kind of hard to cut off the tape in a straight line thus preventing a lot of the edge of the UNI from unraveling. It's also pretty hard to squeegee under there!

After the layup cured, was knife trimmed and removed from the jigs and I cleaned up, it was time to sand the underside of the leading edge. I pulled some of the peel ply off, but not all of it. It turned out better than I expected, given that you had to squeegee the underside and you couldn't see under there very good. There were a couple of lumps, but most of it was fine. I took down the lumps, sanded it pretty smooth and stopped there. The contour was pretty good, so, this is ready for the finishing step.

Given that I left the peel ply on most of the canard, the bondo blobs that I used to fix the canard to the jigs came off pretty easy. I used a chisel to crack them off. I'm hoping the rest of the bondo will come off when the peel ply does.

I am partially done sanding the underside of the leading edge in this picture. I put some towels down on the jig table to cushion the canard and the butt of a hammer to tilt it up. You can also see the bondo blobs, after being chiseled off, on the trailing edge in this picture.

Pretty much the last part was sanding the trailing edge straight with a spline. I went ahead and "made" one at this point, adding some handles to the piece of spruce they send you to make it easy to handle. I used half-sheets of 80 grit, taped together on the backs and stapled to the board to make the spline.

After being sanded, then vacuumed, the canard is now ready for a bit of storage while the elevators are built. I also want to get it off of the jig table to make finishing the other layup on the main landing gear strut easier - I haven't finished that yet and it's still on the table!

I made some straps to hold the canard while I build the elevators. I also covered it up with plastic as I'm not sure how long it will be before I'm ready to pull it down again. I hope these are enough/wide enough straps to keep anything weird from happening while it's hung up...

That's it - Chapter 10 is complete! Now, on to the elevators!