Half a Rudder

Today was the first day I was able to get back out to the workshop in several days thanks to a cold I was fighting and a snowstorm that brought single digit temperatures. The workshop is mostly insulated and I have a baseboard heater installed but it can’t really compete with temps that low, but mostly my wife wouldn’t allow it while I was sick. I guess she cares about me or something.

Anyway, I started the day by spending an hour and a half deburring a couple parts, countersinking some holes, and then final drilling the holes for the shear plates and a couple reinforcement plates into the rudder spar. Two of the holes I countersunk were a little scary. Normally when countersinking I will use a countersink cage but the problem with these holes is that the cage is too big to fit in the right position because the part curves up right next to the hole and gets in the way. Some people get around this by grinding down a side of their cage so that it will fit into tight spots but I decided not to do that. This meant that my only option was to drill the countersink without a cage. I did this by countersinking a very little bit at a time and inserting a rivet to see how close I was. This took a while because I was so worried about over countersinking the holes and tested the rivet a LOT. I actually surprised myself with how well the countersinks turned out which was a huge relief.

The next two holes I needed to debur were the parts that I messed up last weekend. I started by trying to clamp the old parts around them so that I could have a level surface all around the part to place the cage on.

This worked ok but I couldn’t get a consistent countersink because I couldn’t get the parts perfectly level with each other. I think something like this could work in the future but I gave up and just countersunk the holes with nothing else around the parts. One hole ended up countersunk just a tiny bit too far but I’m confident that it is ok to use because you have to look really closely to even notice.

After a break for a friend’s child’s 1st birthday party I got to spend about 2.8 more hours working. Almost all of this time was spent preparing one of the rudder skins. First I had to remove the vinyl that most of the parts are shipped in. I’ve seen other people talk about how much of a pain it is to remove the vinyl from the parts in their blog and until now I didn’t really see what the big deal was. I actually thought it was kind of fun removing the blue plastic from the parts and exposing the shiny aluminum underneath. Well, it turns out that when the part is a large skin the vinyl is REALLY stuck on there and it takes a lot of effort to get it all off. I’m sure the rudder skin won’t be the worst experience I have with the vinyl either.

Once all the vinyl was off I started to debur the edges. Small parts seem to have fairly clean edges and don’t need a lot of deburring but larger pieces like the rudder spar and the rudder skin have little notches from the machines that manufactured the parts. These all have to be smoothed out to prevent areas where stress can focus and eventually lead to cracks in the aluminum. I typically wear these spots down using a file and then give the whole edge a quick pass or two with a hand-held pneumatic grinder with a cut and polish wheel. It’s not a difficult job, but the way the rudder skin is shaped one side of it has several short edges with 90 degree angles  that all have to be worked on.

After I was finally finished I got the skin clecoed to the rudder skeleton and got to see the rudder for the very first time! I still need to debur the skin for the other side, and even after that there is still a lot of work left before I can start riveting things together, but it is a great feeling seeing the rudder coming together.



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