Tonight I test fit the idler bars, and sanded down the flanges of the idler bracket to ensure clearance. These bars are responsible for the transition from one elevator pushrod to another, and must swing freely through the full range of motion. At first they were rubbing slightly on the bracket, but after some patient sanding with Emory cloth I was able to achieve the appropriate clearance. Hopefully it’s enough to still clear the bracket after I prime the parts.
The final step in the brake and rudder system is to hook up the cables to the pedals and then install the the cable guides. I counter sync the cable guides, and pop riveted them in place.
With the rudder pedals installed, I moved onto the brake lines. I studied the Beringer documentation for a while, and then re-read the Aircraft Specialty documents. I started by routing the cables and doing up the fittings finger tight. I realized I would need to step drill the second lightening hole on the rudder bar support. It was a quick effort to step it up to 11/16ths to fit a 750-10 bushing.
With everything routed and looking good, I final torqued the lines, then plugged the two openings on the front of the firewall with plastic caps.
Tonight I installed the rudder pedals. They are held on each end using blocks of hard plastic, and with one block in the middle. I was able to get the bolts into position without too much difficulty. They have an adjustment, and can be moved into three positions depending the the length of the pilot’s legs. I set to the middle position for now.
Tonight was a busy night. My friend Simon came over to help me rivet the firewall flanges, and to torque up the nuts on the fuel line.
We were able to quickly and easily rivet the fittings on. I had to modify one of my rivet gun fittings to grind down one side, allowing it to fit squarely onto the head of the rivet without touching the fitting. Because the rivets were essentially glued in place, I numbered the rivets so we could just call out which rivet we were setting.
Torquing the fuel line required Simon on the front of the firewall with a wrench holding the correct clocking while I cranked up the torque inside. With that done, I installed the flexible fuel line and torqued it also.
Next, I installed the NPT fittings into the brake fittings, including the T fitting connecting to the reservoir. I used Loctite 565. I torqued up these fittings, doing two full turns beyond the initial point of resistance. Getting the clocking right on the t fitting took two attempts.
Then I moved onto the flap motor. This required a carefully drilled hole to hold some safety wire. The drilling wasn’t too hard, and the hole turned out exactly how I wanted.
With the hole drilled, I then installed the motor into the fuselage.
Then finally, I routed the rudder cables forward, and secured the polyethylene tubes in place using adel clamps. These protect the spar from the rudder cable, so they are carefully positioned to do so. Getting the nuts onto the bolts was challenging, but I found it possible using tape to hold the washer and nut, and then rotating the bolt until it caught.
Tonight I drilled the flap torque arms, then installed them into the fuselage.
The flap motor sits between the pilot and passenger, oriented almost vertically. The motor connects to a lever that rotates an arm that extends under the seats out to the wing root on each side.
The arms are match drilled to the center fitting using a template (same one used for the wings). I had to slowly step up the drill size because the steel was grabbing the drill bits.
Once the arms were drilled, it was disassemble and install into the fuselage. Some grease helped squeeze the arms through the plastic blocks and into position.
No pictures today, but I separated the cable links, cleaned up the rust, and then primed them ready for install.
Tonight I used proseal to install several fittings on the firewall. I installed the two brake line flange fittings, the brake reservoir, and the fuel line fitting.
I mixed up the smallest batch of proseal I could find, which was still far more than I needed. I don’t have a way to store proseal, so it’s annoying to have to waste so much.
The hardest part was getting the brake flange fittings into position. Because I drilled holes for the rivets, and because the stainless steel is so hard, there was some careful work needed to ensure the holes lined up with the flange holes. This was the time to test the fit, so I installed the 6 rivets, taped them into position, then placed the flange in place to check the fit. Then I applied proseal and reinstalled, taping everything into position. It all came out well, but I also realized I’ll need a helper to set these rivets once the proseal is dry.
Tonight I drilled holes in the firewall for brake lines, and touched up the paint on the inside of the firewall.
I made a template to help locate and then check the position of the two holes in the firewall where the brake lines will pass through. I center punched the holes, then started drilling with a 1/16th cobalt bit, then worked up to 1/4 inch, then switched to a step drill to get to the final 13/16 size hole. With the holes drilled, I used the flange fitting to locate 6 additional holes around each 13/16 hole, where 3-3.5 rivets will hold the flange fitting in place.
I used some acetone to clean paint off the stainless firewall on the inside, then carefully taped the areas where I want paint (on the aluminum), then turned the fuselage inside down and brushed some paint onto the aluminum angle on the firewall.
Now I’m about ready to proseal the 4 firewall fittings that need it; two brake line flange fittings, the brake reservoir nipple, and the fuel line. once that’s done I should be able to wrap up this chapter with a few more evening’s work.
Tonight I only had an hour or so to work on the plane. I sanded a couple of spots on the cockpit paint, so I can touch them up at a future time. The paint job is ok, provided you don’t look too closely, it has been a good lesson in painting.
The I drilled and cut the rudder bar spacers. These plastic blocks will hold the rudder bars in position.
I also poured some self etching primer inside the rudder bars to help combat corrosion. I cleaned the bars out first by pulling some scotchbrite through then a cloth with some rubbing alcohol.
