|Kaptain Karl's very nice workbench|
Monday, June 09, 2014
Friday, April 12, 2013
Thursday, April 11, 2013
Wednesday, April 10, 2013
Tuesday, June 02, 2009
Tonight Mom and Dad came over for dinner, and Dad and I put the bending brake to the task of bending its first part: the rudder skin.
We used the Olfa knife to cut a piece of .025" sheet from a 12 foot long piece, right off the rack in the garage. After cutting the piece to size, we did a few test bends on the brake with scrap sheet, to get a sense of where to place the bend mark, and where the mark ends up in the bend. Once we were satisfied with that, we started measuring and marking the rudder skin.
Two of the bends are very acute angles - Dave (of Dave's cheap bending brake fame) shows a picture in his plans of him using another piece of angle steel clamped to the pivoting portion to get more bend in the part. We didn't have any extra, so we started by using a piece of 2x4 on scrap to effect the bend. The 2x4 ended up creasing the upper part of the sheet as the sheet pressed against the clamping angle. Dad suggested we use a thinner piece to avoid that problem. We switched to a 1x2, and it worked beautifully. We got three very pretty bends in the rudder skin, all with what looks to be a spot-on radius. And it went pretty quickly.
2.5 hours - Dad
2.5 hours - Me
Monday, July 28, 2008
Sunday, June 22, 2008
*Disclaimer: no actual revenge took place in the day described in this post.
Dad came over for another afternoon of productive plane building today. We started (and finished) putting together the frame for the vertical stabilizer. We then cleaned up the skin I had previously cut out (it needed some deburring and trimming).
Next was one of those parts where I’m never sure I’m ready to dive in, but we went ahead. We put the bend in the leading edge of the vertical stabilizer skin, using the method shown in the Sonex builder’s manual: taking a big piece of 2x4 and pressing down on the skin. It worked like a freakin’ charm! A very nice bend was made. We then started working on fitting the skin to the frame. This was definitely a two-person job. There’s a lot of tension on the skin as you stretch it over the frame.
We drilled a slew of holes, put in a slew of clecoes, flipped the stabilizer over, did more holes and clecoes.
I need more clecoes. I’m ordering some tomorrow.
Most everything matched up great. It is pretty amazing to build various parts, following the plans, and then when you put them together you’ve got a line of holes that follow exactly that piece of channel you just riveted in place. You know that’s what’s supposed to happen, but it still is pretty cool when it actually works.
I said “most everything” matched up great. My bottom cross-piece on the vertical stabilizer frame had flanges that were nominally the right width, but ended up being a little too short and missing some of the holes in the skin. I had to take it out and refabricate it with wider flanges. That did the trick and we were back in business.
You know what is way more fun than fabricating individual parts that by themselves look nothing like part of an airplane? Everything we worked on this weekend.
Look! It’s a piece of a plane!
Saturday, June 21, 2008
Dad and I got some good work done today. When he arrived early this afternoon, I was planning on working on assembling the vertical stabilizer frame, but I had run into a snag: the rear spar assembly was 2” too short. We spent a good half-hour trying to figure out what was going on with that – it looked like we had made everything according to the plans, yet it was short.
We decided to put the vertical stabilizer aside until I could talk to Sonex tech support (only open on weekdays).
We then turned to working on the elevators. Last summer, before my long break from building, we had made the bends for the elevator skins, but that’s as far as we got. A couple months ago, Dad and I had made a rough cut on the the angle of each elevator, and a few days ago I had neatened up the cut, and drilled holes in the hinges that attach the elevators to the horizontal stabilizer.
So today we drilled holes and cleco-ed in the piano hinge and two of the three ribs for each elevator. Once that was done, we did work on the main spar assembly for the horizontal stabilizer. By 5pm, we had all the holes drilled for that as well. Putting, the spar assembly up against the elevators we’d worked on, I could visualize the tail. Very exciting!
After Dad left, I started trying to figure out what was going on with the part we’d put aside earlier. I decided to send off an email to Sonex and wait for a reply sometime next week. I was just about to click “send” when I decided to have one more go at figuring this thing out myself. After some more poring over the plans, I discovered the problem: I had overlapped two pieces of channel that were supposed to meet, but not overlap. There are four pieces that come together at the point in the assembly, and it was a little confusing as to where they began and ended. And sure enough, that gave me the 2 inches I was missing on the assembly. I called Dad to let him know the mystery had been solved.
I spent the rest of the evening remaking the assembly: I had to refabricate both pieces of channel, and used the holes in the spar and the front plate to drill the new holes in the channel. By the end of the night, I had the assembly put back together, minus the rivets.
Remaking parts sucks, but what can you do? It probably sucks enough to make me try harder not to screw them up in the first place. I know I’m getting better at part fabrication, so usually the re-made parts are of a bit higher quality than the first time I made them. It’s probably good to make some mistakes and learn some lessons back on the tail, where it’s a little less costly to remake parts and assemblies – the wings and wing spars are pretty high-stakes.
And lastly – I was admiring our work on the elevators, and it seems like the piano hinge on one of them dips a little on the ends. Grrrrrrr.