Fuel Pump, Almost 14 Mod, Brakes, ELT Mount

Back at the brake lines - they have to have some sort of mount to keep them from flopping around.  I glued down zip tie mounts, wrapped some self fusing silicone tape around each line just to give a little protection from the zip ties (strange stuff - not sticky at all, but as soon as it touches itself, it is almost like it's a single piece) and zip tied them in place.

The spiderweb of lines for the fuel filter and boost pump were next. Having pre-made lines that fit perfectly made this super quick and easy.

I zip tied the flexible fuel line that goes up to the firewall, but I am not going to drill the hole through the firewall for a fitting until I know for sure what firewall layout I need for the engine.

Back to the seat back brace, the modification that never seems to end.  I picked up some structural screws for mounting the brace to the outside longeron (these screws have non-threaded portions on the shank to better fit the holes and provide more strength).  I drilled out one of the existing rivet holes in the longeron to fit a screw/bolt, then put a second new hole in the longeron for another screw and bolt.  There are zero instructions for how much is necessary, so I just went off of what I've seen others do.  The two screws on each side in the longeron are probably enough, but I also wanted one a little inboard to hold the cap to the brace.  I didn't mount anything permanently for now, but figured out all of the lengths and sizes of screws I want to use once it's time to finalize it all.  Given that the brace can come out, I'll probably wait to put it in permanently until I've painted the interior next spring, just to make painting easier.

I had to tweak a number of spots on the outside aluminum caps to make them fit right (ground away places so rivets would clear and bolts would fit).  They're just aesthetic, which made it pretty easy to modify the unseen portions to make them work.  I scratched my head over the center post cap for quite a while.  The holes in it are in standard places, but are just off enough from my holes and nutplates that things don't fit quite right.  That's the downside of them trying to match hole locations that are just measured out by the builder vs prepunched.  After a lot of back and forth and enlarging some holes in the side covers, I finally got it sorted out.  The important thing I have to remember now is that it works okay as long as I screw the cap to the flap housing first and only bolt it to the cross brace after all other screws are in.

A while back I ordered an ELT mount from Van's.  I don't plan on buying the actual ELT for a while yet, but may as well figure out the bracket. It mounts to the J channels just behind the baggage bulkhead.  As is usually the case with everything, I found a standard "well that won't work" issue right off the bat - there is no way to get at the bottom J channel to drill holes into the bracket.  With the tight curve on the fuselage skin, even my angle drill is too big to drill up from the bottom side.  I think what I'll end up doing is taking a small strip of aluminum and making a template out of it with the matching holes from the bracket.  I can lay the template on the top side of the J channel and drill down vs having to drill up. Maybe tomorrow.

At this stage, I don't think there's any reason not to install the brake/rudder assembly in the fuselage.  I'm not going to tighten anything down until I have a better idea of how far forward or aft I want the assembly to set though.  It's a little hard to know for sure without seats.  The one thing I did notice once I had it all in the fuselage is that I made the plastic line that goes between the left and right side a little too short.  It's all going to depend on how much deflection the pedals need with full rudder.  If the line ends up being too short, at least it's a pretty simply swap to put a new one in.

Fuel Lines

I have the new fuel lines now, so time to start the fight of getting those installed.  Since the lines already have the fittings installed, they won't fit through the existing holes in the brackets as they run from the fuel selector valve out to the side skin.  As should be expected, opening up the small holes in the four brackets was of course not as easy as just upsizing the hole.  The hole for the fuel line is so close to the hole for the brake line that upsizing would make them overlap.  The fuel lines came with rubber grommets vs the plastic ones, so perfect holes aren't really necessary.  To keep the holes from running into each other, I used a unibit and slowly chewed away at just one side until I had a fairly large hole started and a different center to reference.  It's more oval now, but with the grommet is fine.  In an ideal world I would have just taken the bracket to the drill press and clamped a sacrificial piece onto the part to put a new center in and used that as my guide, but a couple of these brackets are permanently riveted to the spar carry through.

The professionally made lines are beautiful compared to my attempts using the 3003 aluminum.  The main downside is that the extreme bends required to go from the gear weldment out the skin means they don't exit straight out, but point pretty far forward instead (you can see how it's squishing the grommet and not going straight through).  I emailed TS Flightlines to ask if there was anything I needed to be wary of in terms of bend radius.  He said that even though the lines are quite stiff, they'll actually take a lot more of a bend than most people think.  He said over time they will set into a position, so once they are attached to the tank outlet, it'll be fine.

The flexible lines transition to aluminum at the fuel selector valve and fit perfectly.  Before I start the next step of plumbing the boost pump, I need to jump over to installing the brake lines.  Those have to wind around the fuel lines and run up the center on the floor, so I need those done before the boost pump is in place (sets over the top of the brake lines).

Fuel Lines & Almost 14 Mod

The 3/8" fuel line runs from the wing root, through the side skin, around the gear tower and over to the fuel selector.  All of the online blogs mention how hard it is to get the 3/8" line shaped and through all of the bends without kinking it.  I started at the middle by the selector and weaved it through and around everything to the outside.  The first attempt took forever, and ultimately ended up like everyone said it would - with a kink.  I have a pipe bender, but there's no way to use it because all of the bends have to be made in place.  I have a spring bender, so used that where I could, but the extreme bends to get the tube to exit around the gear tower and go through the skin were just too much and the tube kinked.  The second attempt went a lot better.  I got the 90 degree bend done to the fuel selector and got the bend around the gear tower done.  The final bend out the skin did me in again though, and the very last bend kinked the tube again.

With that, I decided to do what most people do and ordered pre-made fuel lines from TS Flightlines.  They CNC bend tubing for the fuel selector area as well as all of the spider web of tubes that connect everything to the fuel filter and boost pump, then the rest is made of flexible, braided lines. I went ahead and also ordered their brake lines that run down the gear legs.  The plans have you run 1/4" aluminum lines down the gear legs to the brakes, but there are a lot of reports of the flares at the brakes cracking over time since they get tightened and loosened for brake maintenance.  TS Flightlines makes a braided line that should hold up better, partially because of the flexibility, and partially because the fittings they use are a tougher material than the aluminum tubing Van's uses.  I'll use the 1/4" aluminum tube for the internal brake lines out to the fittings that exit out the fuselage floor and the gear towers.

While I wait for the premade fuel lines, I moved on to a few other things.  The flexible lines from the brake pedals will route through fittings attached to the firewall to the 1/4" hard lines that will go down the center tunnel, underneath the fuel boost pump and then out to the gear legs.

I have been waffling on whether or not to do the Antisplat Aero "Almost a 14" seat brace mod.  This mod replaces the standard seat back brace with a much more robust, but narrower one that moves the seat back location back about 4".  I don't really need the extra room that tall people need, but the ability for one seat back to be at the "normal" location and the other to be 4" back adds a feeling of extra width simply because pilot and passenger aren't shoulder to shoulder.  Virtually 100% of the comments I've read have said it's the best mod they ever did for the plane because of that.  The one major downside is that the mod is designed for the sliding canopy.  The tipup canopy will add some complexity to fitting it because of how the canopy latch mechanism works.  There are a couple of different ways to deal with the canopy latch.  I'll deal with that down the road when I fit the canopy.

You can see the difference between the braces in the picture.  The standard brace that I pulled out is on the bottom.  The new brace is the narrower one on top (I think it's steel vs aluminum - it's much thicker and heavier).

Brakes & Fuel Selector

First up tonight was installing the brake fluid reservoir to the firewall.  Because of the variability in firewall forward design, pretty much everything that goes onto the firewall has to be laid out and drilled.  Some pass throughs I will probably wait on until I have the engine to be sure I get them in the right location, like the holes for the throttle cable, mixture, etc.  The brake cylinder doesn't depend on the engine type, so I went ahead and put it where Van's calls out.  It was a little fiddly, since there are two bolt holes to drill, but then a larger 1/2" hole centered below them for the brake line fitting.  After a lot of measuring of the part and double and triple checking, I drilled.  Thankfully the hole ended up where it needed to be.  I still haven't decided if I'll put fiberfrax on the front side of the firewall or not (fiberfrax with stainless foil over it - for greater fire resistance and maybe an extra 60 seconds when I need it most.  There are a lot of arguments about whether or not it really matters.).  If I do, at some point I'll have to pull this cylinder and all other items mounted to the firewall off so I can make a template to cut out mounting slots in the fiberfrax.

I torqued down the bolts, so it's all ready for brake line fitting.

To get started on the fuel system, I took apart the Andair fuel selector valve to change the fittings to the orientation I need.  Based on the directions, I cut a 1 1/8" hole in the aluminum mounting plate that connects it to the wing spar carry through bulkhead.  I shouldn't have trusted the instructions.  Apparently they've changed their design and didn't update the instructions.  The part of the valve that sticks up through the mounting plate is now just 1", not 1 1/8".  It doesn't really matter since mounting screws hold everything on, but with the selector flopping around in the mounting plate, it was really hard to get it lined up for drilling the mounting holes.  3D printing to the rescue!  It took all of 15 minutes to draw and print a collar (the black ring you see around the top of the selector) so that I could more easily center the part in the 1 1/8" hole.  With that done, I drilled the 3 mounting screw holes (not shown in the picture below - the two holes in the plate by the big center hole were pre-drilled by Van's for their own fuel valve.  These holes will get covered up.).

I put nutplates on the valve to make it easier to attach vs using bolts and nuts.

Here it is temporarily installed so I can use it to lay out the fuel lines.  I countersunk the top cover to accept flat head screws vs pan head.  I had to place an order from Aircraft Spruce tonight, so I ordered a few stainless screws.  I think they'll look a lot nicer than the gold cad plated ones.

I started measuring and thinking through how the fuel lines would go.  The fuel line is still soft aluminum 3003, but  it's 3/8" and has a thicker wall thickness than the 1/4" vent tubing.  It's much more difficult to bend by hand.  I practiced a few flares to ensure I knew what changes had to be made for the bigger material (turns out it's the same 4 1/4 turns by the flaring tool as the smaller 1/4" tubing is), then cut a piece to length and made my first bend....and subsequently put a kink in the pipe because I hit it on the edge of the tubing bender.  So scrap that 2' of tubing!  That'll be my practice piece I guess.  Van's gives you juuuust enough tubing to get by with maybe one oops.  I don't like that pressure to potentially put a piece of fuel line in that I'm not 100% happy with, so I decided to order a couple of 12' rolls of extra 3/8 and 1/4 tube.  Of course it's backordered until February like everything these days, but it's super cheap, so worth having on the way so I feel confident in the end result.

Fuel Vent - Right

The right side vent line went much faster than the left.  Next up are the fuel lines themselves.

Fuel Vent Line - Left & Misc

Work has been pretty all consuming the last few weeks, so I haven't had much time in the garage.  I finally had some time to decompress tonight, so got a few things done though.

Just a random tool - I had no idea this existed until I heard someone mention it online.  It's a chuck for my right angle pneumatic drill.  The drill only takes threaded drill bits, which can make life difficult when you need a very specific size bit.  Threaded bits aren't the easiest things to track down (when you just need one and not 50 of one size), so usually have to be special ordered and the shipping costs 10x what the bit does.  This chuck is quite small and threads into the drill, but then can accept regular drill bits.  Having this earlier in the build would have been a huge help.

The vent line fittings that protrude through the forward bottom fuselage skin need some protection from insects, so I prosealed a piece of screen over the external end.  Once the proseal dries I'll trim the excess off.

Since I was mixing up a batch of proseal, I decided to also seal up the gap where the gear leg tower exits the fuselage.  This area will be covered up with a fairing, so it's not visible, but it would allow an awful lot of cold air to sneak into the cabin if it were left open.  The picture is deceptive - it's really a fairly thin line of proseal that will remain once the tape is pulled.

The instructions didn't mention this yet, but I decided to put the rudder cables in place.  The reason being that the fuel vent line has to bend around the cable in one location, so I wanted the cable in place to make sure I gave enough room.

My first try at bending and flaring the soft aluminum vent lines was laughable. The tubing Van's uses is very soft, making it easy to shape, but because of that, it's also really tough to create straight runs.  It doesn't help that it ships coiled up to begin with.  After a few failures, I relearned how to make acceptable flares (note to self - for 1/4" soft aluminum tubing, it's 4.25 turns of the flaring die after first contact - that makes a flare that is in the middle of the .34-.36" flare diameter range).  The first vent line run comes in through the side skin from the wing root and turns forward.  It passes through the vertical bulkhead using an elbow fitting.

This elbow fitting was a nightmare to get in place.  A 30 second job of screwing on the nut on the back side was really a 2 hour bout of frustration and red neck tool making.  The vertical bulkhead has a lip that curls around the back, and no wrench or socket can get at the nut.  I finally had to chop down an old wrench so it was only about 2 inches long and grind the sides away until it would fit in place.  I couldn't get any leverage to really torque the nut down much, but it's as good as it can be.  I'll put some proseal or loctite on the nut just to keep it from backing off due to vibration.

The big bear for the vent line was the forward portion that runs from the elbow fitting, up and around the rudder cable, up to the longeron (so it's above the level of the fuel tank) and back down to exit at the floor.  The bends were bad enough to just get in the right place, but then they are also all in different planes from each other.  For example, in the picture it looks like the top portion starts with a 45 degree angle off of the vertical and just runs forward then back down.  In reality, it comes off the 45, then straight forward, then dives inward a couple of inches under the top firewall bracket, the it takes a sharp curve down and back to the outside, then straight down before it finally goes back towards the centerline and out the bottom.  I'm not embarrassed to say this was attempt number 2!  I got the first one nearly completely done, then on the last 90 degree bend to the floor fitting, I crimped the tubing.  I have a tubing bender that makes very nice bends, but I couldn't use it (or even the spring benders) on that last bend because there is only about 1" of length.  The nut and sleeve have to go on before flaring of course, and when they're on, the length is so short that none of the bending tools can be used without hitting the nut.  Fingers don't make very easy 90 degree bends.  My second attempt worked out well enough to call it done though.  Tomorrow I'll tackle the right side, which I'm guessing will go much quicker.

Fuel Vents

Next up in the instructions is the section on fitting the wings temporarily to set the incidence and a number of other things. I'm going to wait on doing all of that, since it would mean reconfiguring the garage to give me enough space to put the wings on.  I'll come back to it later when I can more easily move benches and/or cars outside with better weather.

That means it's time to start with the fuel system.  After spending most of the day blowing out the sprinkler system, I didn't have much time left, so I just worked on the fuel vent fittings.  These are standard fittings that are modified to act as fuel vents.  I put each fitting in the drill press and took a file to the threads on the bottom half to smooth it out.  This wasn't all that necessary, but I think it'll look better than leaving the threads.  After it was smoothed out, I cut each fitting at a 45.  I'll have to find some screen to proseal over the opening to keep the bugs out.

Misc Parts

 I haven't had a chance to do much work on the plane (even though it's getting really close to being ready to flip the fuselage over so I can move a lot faster), but why should that stop me from buying goodies for it?

The high pressure fuel pump and filter are needed to back up the mechanical fuel pump since I'm going with the fuel injected engine.  Van's sells a kit that includes the pump and filter, as well as the housing for it.  It'll be installed on the floor in front of the seats.

This is a picture from another builder's site.  The housing has a place for the fuel selector valve and covers the pump.

The standard Van's fuel selector valve leaves a lot to be desired.  It looks like a valve I would build with parts from Home Depot.  I'm sure it works and is a cheap solution, but it seems like a shame to spend a lot of time making a nice interior and then have an eyesore for a fuel selector.  I decided to spend a few extra bucks and get the Andair valve, which is a beautiful piece of machining.

Van's used to include super cheap plastic air vents with the kit, but virtually everyone threw them away because they leaked so bad.  So now the kits don't include vents as standard. I ordered aluminum vents instead of going with the cheaper plastic version.  I can't remember the last car I had that didn't end up having a broken plastic air vent.  I think aluminum will last a lot longer, and they look much nicer.

The electric flaps don't include a way to set any position detents.  I suppose I could go the counting method and always count to 3 for X degrees of flaps, another 3 seconds for Y degrees, but I'd much rather have a method that is just automatic.  The Show Planes system has a collar that goes over the flap actuator and can provide a reference point for varying degrees of flaps.  The control box hooks up to the switch on the panel so that the flaps can be set with just a flip of the switch, and you can bring the flaps back to full up without having to hold the switch.

I'm going to install the ADAHRS box for the EFIS behind the baggage compartment in the tailcone.  In order to be calibrated, it has to be level and not necessarily with the angle of the airplane structure.  The tailcone doesn't sit level, but Van's has already done the geometry and has a cheap, slightly angled bracket that can be riveted to the J-stringers of the top tailcone skin and it automatically sets the bracket at level.

Lastly, as much as I hate the stuff, I ordered more ProSeal (well, not actually that brand, but it's kind of like Kleenex vs tissue).  I am all out of the batch I used to seal the fuel tanks.  I definitely didn't need this much, but it's the smallest container.  I will just need some for varying things as I build.  It's not technically a glue, but that's what everyone uses it for.  I'll use it to glue in the naca vents for the air vents, sealing leak paths in the tip up canopy at the hinge, attaching wire zip tie brackets, etc.

Right Fuel Tank - Fixing a Leak

 A couple of days ago I leak tested the right fuel tank.  Everything looked good except for one small area at the outboard top corner where the baffle and outboard rib meet.  These corners are notorious for having leaks because of how they have to be put together (put a huge blob of proseal sticking up in the corner and hope it smooshes down just right in all of the right places when the baffle is pressed down - there are actual gaps it has to fill, whereas in all other areas it's sealing two tight surfaces together).

The leak can be seen where the bubbles are coming out between the baffle and the skin between the last two rivets.  The other bubbles are just from spraying the solution.

Luckily, this area is right inside where the fuel cap filler flange is, so access was easy.  I pulled out my borescope and stuck it in so I could see what the proseal looked like in the corner.  As expected, it was kind of a mess.  It's super thick because I put a big blob there, but apparently there were still gaps somewhere.  To fix it, I just used a gloved finger and spread a bunch more proseal over the corner and along the edges.  It's a lot of sealant, but after leak testing again (a few days later - I'm late updating) it seems to have done the trick.  No more leaks.  If I remember to, I may do one more leak test on each tank just before I install them on the wings for good.

Right Fuel Tank - Finished!

Calling the fuel tank "finished" before it's leak tested might be jumping the gun a bit, buy I'm optimistic.  Today was a long day, but once you start closing things up, there aren't a ton of great stopping points.  All in all, it went pretty well.  I modified a few processes from the first tank, did better at some things, and created new mistakes with some things.

One lesson from today is that when there is something that needs to be done, I need to mark it in a very obvious way, otherwise I just forget all about it.  Case in point, in my final inspection of the internals of the tank, I decided there were two small areas at the front of two ribs that I wanted a little more proseal on.  Because I hadn't mixed up the proseal yet, I didn't have any handy to just dab on at the moment.  Fast forward a while and as I started riveting on the baffle, I remembered.  Too late.  I think it's probably okay because I was just going to add more out of an abundance of caution, but I won't know for sure until I leak test everything.

One thing that got me on the first tank as well as the second tank was the fit of the baffle.  I don't know what the deal was, but on both tanks, the lower side skin was skewed by maybe 1/64", so the holes for the baffle/skin joint were slightly off.  The baffle went together with clecos just fine, so I didn't notice the issue until I started putting rivets in (they wouldn't go in).  I'm still not sure what happened, especially since the exact same thing happened on both tanks. I had to hit each hole with a reamer to just knock a little bit off of the hole.  Even with that, the rivets wouldn't sit perfectly flat (because the skin in that area is countersunk, not dimpled - the dimples would have had a lot more forgiveness).  They are just slightly at an angle - just enough to be able to catch a fingernail on one edge of the manufactured head.  The top skin is perfect, so I'm not losing much sleep over it.  It won't be noticeable for anyone who isn't out to find errors and crawling around under the wing!  It was just a bit strange to have this happen on both tanks.

After finishing the baffle/skin joint, I got the Z-brackets installed, then sealed up the access plate.  I flipped the tank over to let gravity do its work and pull the proseal down onto the baffle joint while it sets up.  Before I put the access plate on, I took a quick look, and at least as far as I could see, there is a nice bead of proseal along the baffle.  It's pretty cool out right now, so I'll probably give it 3 or 4 days before I leak test it all.

Right Fuel Tank - Plumbing

I worked on the plumbing and access plates today.  Everything is done except for sealing the access cover.

Right Fuel Tank - Leading Edge Rivets

I still had maybe 9 or 10 remaining rivets to do in the very leading edge of the tank.  The awkward angle of bucking and using the gun when the tank was in the vertical position meant that I bent over the shop heads more often than not, which is why I got help on the previous tank.  I'm impatient though, so instead of waiting for help, I figured I'd give it another shot myself.  This time I took the tank out of the jig and tried riveting with it just laying flat on the table.  This allowed me to hold the rivet gun much more normally.  Reaching around and into the nose with my bucking hand was just on the edge of physical limits, but in the end it actually worked out great.  I was able to finish up all of the rivets just fine.  I wish I had tried this approach on the last tank!  Oh well, next plane I guess.  Tomorrow I will seal all of the rivet heads and should be able to get all of the plumbing finished up.

Right Fuel Tank - Sealing (4)

I riveted the two ribs I had prosealed yesterday then did the inboard and outboard ribs.

I had a senior moment and put the rivets in backwards for the nose doubler and the patch that seals up the tooling hole.  Well, there really is no backwards, except that I would generally put the shop head on the inside where it is hidden.  I wasn't thinking and put the shop heads on the outside of the rib.  They'll never be seen unless the tank has to be removed from the wing of course.  Next up is the plumbing and baffle, and then the tanks will both be done!  

Right Fuel Tank - Sealing (3)

Nothing too exciting to show, but I got two more ribs gooped up and clecoed in.  For a split second I thought about going ahead and riveting them with the proseal wet, then I came to my senses.  I'll wait until tomorrow!

Right Fuel Tank - Sealing (2)

This afternoon I riveted the three ribs that I prosealed last night.  All in all it went pretty well.  I'm done with these ribs except for the couple of rivets along the very nose of the tank.  I attempted to do those by myself, but just like on the other tank, the rivets came out pretty bad because of the awkward angle required.  I'll get some help doing these.

Fuel tanks - Leak Testing & More Sealing

Time to see if all of the work has paid off.  After a few false starts due to caps that weren't quite tight enough and were leaking, I got things sorted out and started the leak test on the left tank.  All this involves is putting a schrader valve in the drain opening, capping the fuel pickup fitting, and putting a balloon on the vent line.  It only takes 1-2 psi to do the check, so just enough to blow up the balloon a little bit is all that is needed.

One thing that Van's calls out is the need to cover the filler cap with tape, since it's not perfectly air tight.  Laughably, this turned out to be the hardest part of the whole process.  I tried packing tape, but no matter what I did, I couldn't keep it from leaking (sprayed it with soapy water to test).

I finally switched over to heavy duty Gorilla tape.  That seems to be working, but we'll see what things look like in the morning.  The only problem with the balloon test is that it'll inflate and deflate depending on temperature.  I did spray the entire tank down with soapy water and didn't see any leaks beyond the filler cap, but if tomorrow the balloon is deflated and I can't tell if it's because of temperature or a leak, I may switch to using a water manometer instead.  At least with that you can mark the water level at a specific temperature and then wait as long as you need to for that temperature to be hit again to recheck the level.  Given what I've seen so far, I'm cautiously optimistic.  I think may actually have a leak free tank.

I went ahead and got started on the ribs of the right tank.  It's amazing how much faster things go the second time around.  I prosealed and clecoed 3 ribs.  I'll shoot the rivets tomorrow night.