Firewall fittings and rudder cables

Posted on by Neal

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.

The brake line flanged fitting before riveting
Front of firewall brake flange fitting.
The brake fitting after riveting. Note the numbering to identify rivets

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.

After torquing the fuel line nut

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.

NPT fitting installed

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.

Flap torque arms

Posted on by Neal

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.

Drilling the arm using the template
Installed arm, showing at the wing root where it connects to the flap
Center fitting to which the flap motor will connect
Looking down into the cockpit, the flap motor will mount on the space to the left

Firewall fittings

Posted on by Neal

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.

Fuel line fitting clocked to 5 degrees
Brake reservoir installed
Inside view of brake line fitting… behind all that tape
Tape holding the rivets in position while the proseal hardens

Firewall work

Posted on by Neal

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.

Using the step drill to up-size the holes
Brake line flange fitting holes. The fitting is slightly closer to the top of the hole than the bottom, but it fits ok

Rudder

Posted on by Neal

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.

Rudder bar spacers. These will be bolted to the sides of the fuselage to hold the rudder bars in position
Self etching primer used inside the rudder bars

Painting Cockpit

Posted on by Neal

I decided to go ahead with the top coat and to paint the cockpit dark grey. The paint was thinner and spayed quickly and easily. I did two fog coats, and then a wet coat. I’ll plan to do one final coat tomorrow to fill in areas where i missed, or went too light. It’s hard to tell what it will look like once dry, but I’m hoping it will be decent.

After the first fog coat
After the first wet coat

Cockpit painting

Posted on by Neal

Tonight I applied another coat of light grey primer to the whole cockpit area. There are a few spots where access is difficult with the spray gun, so I rotated the fuselage around a few times to aid with access.

I have a darker grey finish coat that I’m planning to apply next. Painting is a lot of work, and I’m not great at it, so I’m considering just leaving it light grey and moving on. My only concern with leaving it light grey is the possible reflections on the canopy. The downside of a darker color is more heat trapped in the cockpit on hot sunny days.

I will see how I’m feeling about it tomorrow.

Brake cylinders

Posted on by Neal

Tonight I spent time sorting through the various documentation that came with my Berlinger brake kit, and then installing the brake cylinders on the pedals.

Berlinger is a French company, and therefore their native measurements are all metric. That’s not a comprehension problem for me, in fact it’s my preferred method, but it does get confusing when mixing metric and imperial. The brake cylinders seem to be all metric, but the hardware supplied to install is imperial.

Berlinger supply an “installation manual” for the RV-14 kit, but it is not at the level of detail I’ve become accustomed to with Vans. Some of it was just wrong. For example, the diagram, and supplied install hardware, calls for AN3-10a bolts. At the bottom of the cylinder, those bolts are too short to provide clearance from the rudder pedal itself.

I ended up using their supplied hardware for the top of the cylinders, but used a longer AN3-12 bolt with a castle nut. The castle nut isn’t really necessary because Beringer supply a rod end bearing that does the rotating. But, in the even the bearing started binding, it is good to know the nut would not come off.

Interestingly, I discovered that the left and right rudder bars are not identical. The right cylinders needed less length that the left (or vice versa?). This must be due to the geometry once installed.

Next I’ll be working out how these lines attach via Banjo fittings. Hopefully it’s not too complicated, but it will require some more research.

Top of the cylinders. AN3-10a, thin washers
Bottom of cylinders. AN3-12, combo of washers, an a castle nut. Note the difference is threads showing on the rod end bearings. This is because the left and right rudder attach points are different lengths.
The two sets of rudder pedals laying on top of one another.

Installing pedals

Posted on by Neal

I guess I didn’t really finish the rudder pedals yesterday, but tonight I did. I installed them into the rudder bars, applying some grease and torquing the castle nuts so that there’s minimal play, and also minimal friction.

Rudder pedals bolted into the rudder bars