The temporary firewall is pretty straightforward. I didn't take any pictures while it was under construction, but you can see it here in the lower left of the image. I mounted my bulkheads to the wall as I built them since my kids play in my workshop a lot (when I'm away on travel) so there is less chance of my stuff getting damaged this way.
The permanent firewall has bolts set into it to accept flight control pulleys and the engine mount. These get floxed in, after glassing one side and drilling and counter sinking the bolts. You also grind a flat on the bolt, so, when I floxed the bolts into the I worked a bunch of flox into the space that the flat left to (hopefully) keep them from spinning later.
In this photo you can see the lower section of the permanent fireall with the bolts floxed in in a similar manner. You can also see one of the fuselage longerons being laid up in the background.
Chapter 4 - complete as of July 5, 2001 (or so I thought...)
When I started working on mounting F28 into the fuselage, I measured and marked wrong. Actually, I didn't measure wrong, I put the bulkhead on the wrong side of the mark. Then, when I sanded it to the "right size" in ended up too short. I e-mailed Nat and he said I could cut it in half, lengthen and then put some new BID and UNI layups over the joint. I did that, but started on the part before he replied to my second e-mail. I did the extra layups partial length, then read his e-mail where he said full length. That's not going to work...
My third attempt, second part, I tried to cheapo charlie and used scraps of BID instead of full-length pieces. Not sure why I did that, but, I ended up with a lumpy part, one that wasn't the same width (the skinny way) over its entire length and even managed to get a nice bubble right in the middle of the layups. Scratch that one - what's the score? Oh yeah, onto my fourth attempt.
Given that my second attempt was the right size/length, and not wanting to start completely over again, I delaminated the extra layers I added. Then, I added 2 layers of UNI full length, both sides, and hoped for the best. If I didn't mess up and sand this one too short, I'd be able to settle with my fourth attempt.
Chapter 4 - complete (again) as of January 19, 2002 (or so I thought...)
When I began cutting the holes in the lower permanent firewall for the electrical channel, I flubbed and made a big cut on one side that wasn't needed. About that time, I had done some reading through the archives for the mailing list and found some ideas for the firewall after, obviously, I had made the first one. Given that 1) I wanted to make the aluminum inserts bigger and 2) I wanted to redo the floxed-in bolts, I made this part over. I did and the result, nearly finished, is shown here. I made 2" square inserts (with the corner trimmed off - see the image - they're much bigger) and carefully cut the holes needed over so I wouldn't have to make this a third time.
Hmm guess I'll have to re-shoot this photo. You can't see the safety wire, but you can see the bolt heads. Some builders have had their flox-captive bolts turn, others say that the torque required for these bolts (15 inch/pounds) should never be able to turn a flox-captive bolt. I bought drilled-head bolts, installed them (no flox) then safety wired them so they woudn't turn. This photo shows the firewall already installed, you can't see the other two bolts.
Chapter 4 - complete (again) as of March 10th, 2002.
