Archive for October, 2005

Longerons, side skins, and firewall

Monday, October 31st, 2005

Another week with much progress. I attached the forward side skins. I decided to be “bold” and bend the rear curve first. This worked out just fine, although a bit frustrating. I did end up slightly cracking the corner of the sharp bend just like they tell you not to do in the instructions. I stop-drilled the crack and removed the failed material. This is seen as a 1/4″ long notch at that corner. It is fine, just an extra stress-relieved bend. Also seen in some of the images, I needed to adjust my bend to come a little more in line with the bottom of the side skin.

I also cut the holes for the side steps AFTER doing the bend. I think that was a wise choice, as doing it before would have complicated the bend. Have you ever used a fly cutter in a cordless drill? I cut the step holes with the skin on the plane. That was exciting in a terrifying kind of way. Nah, not really, I just turned the fly cutter super slow and used it more as a low speed scribe than a high speed cutter. It worked great.

With the side skins on, I match drilled the arm rests (no brainer) and longerons. Drilling the longerons was one of those processes that requires lots of time and patience. This is also a good process to slow down and do it right the first time, yet not be petrified by the profound nature of what you are about to undertake. Ok, so this seems like an important step. I started from the aft of the fuselage and worked my way forward on both sides. I used a lot of clamps and checked to be sure I was progressing with the top of the longeron flush with the side skin after every couple of holes. I did try to leave just a bit (just a hair) of overhang on the forward skin to account for edge deburring. No big deal, but I’m at least trying to be smart about such things. Alright, so after about six hours and a whole lot of Boelube across two sessions, I completed drilling the length of both longerons. That is a lot of holes. I should note that when I got to longeron alignment at the seat back bulkhead (I forget the part number), it seemed like there should be some consideration for the fact that there is a bracket part that fits between the bulkhead and the longeron angle. It seems that you could get the longeron drilled too close to the top of the bulkhead such that the part that goes between wouldn’t fit later. So, I used a spacer to space the longeron angle off the top of the bulkhead while drilling it.

The forward sharp bends in the longerons came out surprisingly well. They matched the skin just as good as when I did a test alignment against the skin when I was bending them (shouldn’t be any big surprise). I did find that I needed to put some extra twist in the longeron to make it match up to the firewall engine mount angles partly because the side skin wants to take the twist out of the longeron. No big deal, a little extra twist and things came out fine. (picture shown is before extra twist).

Next up was to put on the firewall. Whew, another critical operation. I followed the instructions, used some more Boelube, and the firewall and bottom forward skin are attached.

 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
 

Center and aft sections joined

Tuesday, October 25th, 2005

Somebody grab the camera!

So it was that I had this beautiful center section sitting on the bench and nobody to help me move it (it is kinda’ heavy now). Oh, wait, who is that coming home from work that cares much less about airplane building… (super hero entry sound) It is Tanya! Hey, (big hug, and a kiss) wanna’ help flip and attach the center section! (can you tell I’m in kiss ass mode here? I know there is some ugly riveting coming up, but she doesn’t.) “Sure” she said, and we spend a bit of time getting these two sections put together.

Ok, it was a little frustrating getting the bottom skins clecoed together. A little wiggle, jiggle, and we won’t talk about reaching for the hole with the clecos. In the end, it all looks pretty good. That is where we left it. Not too bad for a week day evening.

 
  
  
  
  
 

Primed and Riveted center section

Monday, October 24th, 2005

Alright, this weekend started with a big push to get the center section parts primed. All of the ribs had been scuffed earlier in the week and Tanya spent a couple of hours on the driveway Saturday morning washing them in soap and water. Everything was dry by the time we got back from lunch (Chipotle Grill, yum). Back from lunch fat and happy, it was time to prime. Tanya mixed the primer and I setup the hose and gun.

By evening everything was dry and I was ready to start assembly. This scene is kind of like Christmas morning. I’ve got a freshly primed batch of parts that are just crying for rivets. Don’t even try to capture my attention for the rest of the day. Tanya is well aware of how this goes so she was off to a friend’s house to hang out for the rest of the evening. Is she the best or what? She helps prime, then vacates when I dive in for assembly.

Ok, back to airplane building. I began by installing all of the platenuts that attach the seat skins to the ribs. I had also prepared a few platenuts on each of the center ribs for the attachment of adel clamps for securing wiring. (end of the long descriptions) Then on to my baggage tie-down solution. I don’t know how the vans recommended solution would be worth anything.

Guess who showed up when it was time to rivet on the bottom skin. Yep, Tanya was on deck with the rivet gun for a couple of sessions of skin riveting while I bucked. So we finished driving the bottom skin rivets and set the assembly back up on the bench. It sure is easy working on the center section up on the bench. This is the idea behind all of the pre-emptive efforts with mounting the strobe pak, ELT, baggage tie-downs, and wiring conduit and securing.

 
  
  
  
  
  
  
  
  
  
  
  
  
  
 

scuffing, deburring, dimpling

Thursday, October 20th, 2005

Spent a couple hours scuffing and dimpling the center section ribs. Also started deburring the center bottom skin (lots of holes to deburr).

 
  
 

fun toys

Tuesday, October 18th, 2005

Well, I don’t know how much fun one person can have building an airplane, but I fully intend to find out. Part of that for me is having a real good excuse to buy some great toys (tools) along the way. None of these are for the timid pocket-book. Greenlee punches, a 1-15V 28A DC power supply, and a zip-tie gun.