Unintended Adventures

Month: March 2016

The beginning of an end

This past week was spring break so I didn’t have to go to any class. We had decided back in January to go somewhere and with some good luck on our side we made it to Paris (the French one). We left Chicago on Sunday and returned to Chicago on Thursday. It was a short trip, but we think it was the best amount of time. Not too long to get bored of the city and not too short to not see the few big items on the Paris checklist. It was a lot of fun and we ate a lot of good food and more than the average persons baked good consumption. It did mean that there wasn’t a lot of time left over the break to work on the airplane, but we did manage to get a few things taken care of.

First, I worked on wrapping up the boot cowl. I feel like I have said that for 4 1/2 months now, but it truly is getting closer. Between yesterday and today, I got the cowl strips drilled out. This was a chore in itself and I never did it the same way twice. You have 3 small strips and 3 wider strips to place and transfer drill so you get a lot of time to screw up and try different ways. My boot cowl will have several 5/32″ rivets in it due to holes becoming over sized. If you recall my last posting, we had decided to not place the strips in our initial drilling of the boot cowl skins from the firewall support angle tabs. So what that means is that I had nice #30 holes and then I came back around and transfer drilled through them into the cowl strip. At first I was drilling through the boot cowl skin into the strip. This is problematic because the tab on the firewall support angle is probably not going to stay put and you end up enlarging those holes. That’s bad because then a rivet or cleco won’t keep those pieces together. It took a while for me to get everything lined up, but I did get the majority of the first strip drilled out to #30 with about 10 5/32″ holes to cover up mistakes. As a note, I spent a lot of time realigning the strip and support angle to the boot cowl skin so I didn’t make a lot of holes. Some better sheet metal workers might know some tricks, but I don’t and I went very slowly.

The next piece was the larger cowl strip. This is the piece that the cowling of the plane will eventually attach to. This piece seemed easier probably because I had spent 2.5 hours on the smaller pieces the day before. Another part that made it easier was that is was on the inside of the firewall support angles so it just needed to be pushed flush against the support angle and it was set. You should take note that everything is straight or use a lot of tape. This strip seemed to be steel (Thought of that after I sat there drilling into it with a standard bit) and it didn’t want to conform. We had a nice chat together and it finally agreed to behave. The other part is that I was now transfer drilling through 3 sheets of metal, so everything would sort of line up when I put the drill bit through the hole. I’m positive my holes are not perfect #30 sizes, but the clecos hold and everything seems sturdy. I’ve got it on my list of things to talk with Ed about the next time I call RANS. This drilling took half of what the smaller spacer strips did.

One other thing to bring up that I may not have mentioned is that a transfer drilled all the hole in the top skins from the firewall support angles and then I proceeded working with the small strips and then the larger cowl strips. This probably contributed to the holes being enlarged. I’m not sure an easier or better way to do this, so I will ask the all knowing this week, after I have completed the task and can only kick myself 🙂

Maria helped out this weekend as well and she doesn’t like me to watch over and scrutinize her work, so we found some tasks that needed to be done that were relatively quick to do and she had something to show for it afterwards. If you are wanting to involve the family, spouse, or friends in the building process, deburring and sanding is not the best thing to make them do the whole time. Although it cuts down on the time I have to do that stuff, Maria is no fan of deburring sheet metal for two hours. I’m not either which is why I like other people to do it 🙂

Maria put together and riveted the pedal assemblies together today and installed the rudder cable pulleys and cables in the tail yesterday. We’re getting a lot of things checked off the pre-covering checklist. We did have to sit and stare at the pedals before riveting to decide on when to paint them. In a perfect world you probably would paint each piece on the back and then rivet everything together and paint the front. But since you will probably never see the backside of my rudder pedals, we decided that as long as it looks decent back there, we won’t worry about it at all.

A fellow local S-20 builder found some neat two-part spray can paint from Eastwood. He tried it on a few parts and it looks great. They have a rat-rod black which looks really good and I think I’ll be using that for quite a few of the small things on the airplane.

And for my last complaint, my large boot cowl strips don’t seem to be aligned the best. They all meet at a good point and appear to be flat against the firewall, but they still are slightly tweaked. Cosmetic things on this airplane are very frustrating for me

(6 h)


  
  

  

Boot Cowl Blitz

Today was a very successful day. I had two friends (Rich and Bob) come down to assist in the building process and we got a ton done on the boot cowl.

First step of the day was to clean up the sides and transfer drill the holes from the stiffeners to the sides of the boot cowl. After that we riveted them to the boot cowl sides (Pro tip: Do not rivet the top stiffener on each side. You will need to transfer drill through the skin into the top side boot cowl skin. Luckily, aluminum rivets are easily drilled out.).

After that, we fitted up the instrument panel frame to being fitting the top boot cowl skins. We had to remove some of the frame to clear some welds, but nothing major. One thing we couldn’t figure out is how to attach the instrument panel to the panel frame without riveting the panel frame to the fuselage. The panel frame has a mounting hole that corresponds to a tab on the fuselage, but the panel does not. So we just rolled with the panel frame and did a lot of checking and measuring to make sure we were staying flush with the tabs on the firewall. In the end, this seemed to work out, but I guess we won’t really know until the panel goes in.

The top sides sit right against the tube that connects the firewall and the top of the fuselage. I think there will be a rubber grommet there, but there isn’t much space. I’m going to look into that because I know it needs something there and I don’t know if I have enough space.

When we first started putting on the top sides it didn’t seem like they would reach down to the stiffener location on the side skin. After transfer drilling holes starting from the middle at the top and moving outboard, everything did fall into place. We spent a lot of time looking it over and I would suggest the same to others getting to this part of the build.

Another thing that we did was to transfer drill the top skins from the firewall tabs without the spacer strips in between the tabs and top skins. We thought that this was making it too complex and we will do that on the next work day.

After we finished, we had drilled out all the holes for the boot cowl. The next items are to fit up the spacer strips, fit up the instrument panel visor, and debur. A lot of deburring.

Big thanks to Rich and Bob for the help. We got a ton of stuff done that would have taken me weeks probably at my current pace. Also, it was a lot easier to have help when fussing with the boot cowl. I wouldn’t have wanted to do it by myself.

Next potential build time is over spring break which will be in two weeks. Midterms are this week which are stressing me out, but I’m not the first. I always have trouble breaking these engineering problems down. I think I just need more practice!

(18 h)


  
  
  

Powered by WordPress & Theme by Anders Norén