Chapter 21 - Strakes & Fuel
Since I had 8 * 4 sheets of foam I was able to cut each of the upper and lower skins in one piece. (no inner and outer skins and no 5 min epoxy joins) You can easily get two complete skins out of an 8 * 4 sheet. I was going to use a spare 4 * 4 piece of 3/4 ply for the table, but rejected it because it had warped in the Florida humidity. Plans talk about the table and fuselage being level fore - aft, but don't mention the fact that the spar is angled, so the table has to be higher at the outboard end. I got some 3/4 chipboard and built the table with legs on one side longer than the legs on the other. I took a tip from Wayne Hicks and used drywall screws to screw the table together. Once the table was roughly in place I removed one of the legs (easy with screws) and manouvered it behind the gear leg, then shuffled the table aft until it butted the spar. Now I lifted the wheel about 1/2 to get the spar to sit on top of the table, then I screwed the fourth leg back on. Amazingly, once all this was done the fuselage and table were within 0.1 of level (in the fore / aft direction). A small nudge on the trestle holding the nose and a 1/16 sim under the table leg got my electronic level beeping nicely.
When I studied the drawings, there was one thing that didn't make sense. I expected the strake to go all the way to the wing, but it doesnt. There's a large V shaped area at the outboard end called the fairing block. I suppose this helps you fair the strake to the wing. I used a spare strip of blue wing foam to get the fuselage curve, then trimmed the skin to contour using my strip of blue foam as a guide. But... when I trimmed it changed the longitudinal dimension, so my skin started at about FS 62 instead of FS 60. No problem. I added a 2 inch strip at the back (where it doesn't have to curve). After a lot of "fiddling" measuring, sanding and remeasuring butt lines and fuselage stations I finally got the skin to sit where I think it should be and bondoed the pine board in place. The strake is like a jigsaw puzzel and you have to make quite a few guesstimations of where things should go. For example - where is FS 60 anyway? I used the 118 measurement for the front of the spar and checked it against the forward face of the IP. the pine board is supposed to be at FS 60. Which side of it? I'ts 55 inches long, but do you angle it to fit the fuselage side? Which side of the rib goes at BL 33? I messed around with these and other issues for a while before getting everything to fit fairly well, erring on the side of having a bigger fuel tank whenever I wasn't sure. 
I didn't want to put nails through everything, and it's tough to get the bottom skin to stay curved, so I settled for holding things in place. I'll do final adjustments to the bulkheads when I'm setting them in place. I cut and sanded the hole for the fuel sump. In the main drawing it looks like this holes butts up to the fuselage skin. The section shows it an inch or so away from the edge. I followed the section and made it about 1.5 inches to allow room for a glass to glass bond around the rim. Everyone seems to have problems getting their tanks to hold pressure first time around. I'm shooting for a first time seal. We'll see.
Once I had the first bottom skin cut to the correct shape, I used this one as a pattern to cut the other three skins. My theory here was that, even if they're a little off (I don't think they are), at least my two strakes will be the same. The differences in the plans dimensions for top and bottom skin are minimal - 0.2 at most. I felt it would be good to have all the skins starting off the same size. It's no problem if I need to trim or add a little here and there to get a good fit.
I decided I didn't like the plans method of nailing everything at once. Instead, I worked through the issues one by one. These are the steps I took in order:
The above procedure worked for me. It allowed me to seperate the issues into stages rather than having to get everything right at once. It took two days of elapsed time, but I think it was easier - and I don't have the famous (from archives) bump in the leading edge, or a bunch of holes in my skins and bulkheads. I disassembled the table and moved it to the other side.
The second strake went without a hitch, using my staged method of assembly and the first strake as a pattern. I BID taped the first (left) strake and gave it a liberal coat of epoxy. I got some AL screen from Home Depot and made two tea strainer type domes for the tanks. Had the rest of a roll of AL screen left, so Char, always quick to spot an opportunity, asked me to replace the screen on the front door. Millenium celebrations at our local nudist club took their toll on productivity. I also discovered that I didn't have the AL tubing needed for the vent pipes, so I've had to put off attaching the strake top skins until the tubing arrived.
Sitting in the hot tub one night, I looked at the right (Chars side) strake and thought - that's not right. The TTE bulkhead seems to be too low. I jumped out and looked more closely, then went around and looked at the left strake. Got out my level and tape measure. Sure enough, the leading edge bulkheads were too far aft and too low. Next day I did some more measureing and figured out that the first, smaller bulkhead was angled downwards a couple of degrees and met R33 about 1/4 inch too low. The r33 and r57 bulkheads were in perfect position. The TTE bulkhead followed the same line. No option.
I got a hacksaw blade and proceeded to cut the bulkheads out and repositioned them. When I moved them to the right position I had a large (3/4 inch) gap between the bottom skin and the outboard end of TTE. At the inboard end it was about 1/4 inch out. I have no idea how I missed this when assembling the strake. I added a strip of foam to the bottom skin and a ply of BID to hold it. Once this cured I BID taped (with 3 inch tape) to join everything together. Looks fine now. No one will ever know.