Welp, looks like I’m done bending and flaring tubing, at least for a while. Actually, I don’t think there will be any more hard lines to bend until I get around to attaching the wings and hooking up the fuel system. Today I took care of the hard brake lines, which run from a junction point under the forward baggage bulkhead out and down through the gear towers. When I did these before I discovered that I couldn’t use the bulkhead fittings like I’d wanted, and would have to reverse them. Things got even more complicated this time out. For each side of the aircraft, there’s a 90° bulkhead fitting at the junction point, and another 90° bulkhead fitting at the base of the gear tower. Except there are only two 90° fittings in this kit. Without the fittings at the base of the towers, these brake lines have to be left half done, which kind of kills my goal of finishing them while the forward side skins aren’t in the way.

Fortunately, I have to extra 90° bulkhead fittings, which I ordered to use where the lines pass through the gear towers. I also have two extra 45° fittings which would have been used for the vent lines, had I gone with the factory method. So I decided to use the 45° fittings for the gear towers passthrough, and repurpose my extra 90° fittings for the floor passthrough. With that settled, there was just a lot of bending to do. The lines inside the gear towers are pretty straightforward, but the lines from the towers to the junction are a little more complex, mainly because of how far out they have to stick due to me reversing the fittings. For both of these spots, I ended up making a first pass at a line, which ended up messed up, but worked as a prototype for the actual line. This has been a kind of common theme actually…

Anyway, here are the lines from the junction to the towers:

A close look at the gear tower passthrough end:

And one of the lines inside the towers:

Finally, here’s the large pile of scrap leftover after all this tubing work. Not pictured is the 3’ long remains of my first attempt at the long fuel line across the fuselage:

So tomorrow it’s back to the rudder pedal assemblies. I suspect those will be an all-day job (maybe more), but after that I think I’ll be done mucking with systems for now, and I can get back to putting the tailcone together.

Today I got my shipment from Spruce, which included a new stock of 3/8” tubing for that last remaining fuel line. I decided to work on that and continue punting on the whole brake line issue. I hacked up my previous failed attempt at this line and used it to prototype the shape of the finished product. Amusingly enough, there was actually still enough tubing to have made this line without the new stuff – but that’s OK, because this prototype was still not quite up to my standards. But it made a great template for the final product.

Here’s where the line will exit the right side of the fuselage. Note that there’s a 90° forward bend here, unlike the straight-out exit of the left line. This is to accommodate the flop tube in the right tank. The regular fuel pickup exits the tank near the back, but the flop tube exits up at the nose of the tank. So this line must run forward, parallel to the fuselage, and through the inboard tank mount to connect to the flop tube fitting. There will be a union fitting here to connect the short line up to the pickup fitting. This is presumably to ensure that this line can be removed after the fuselage is complete if necessary. (The B-nut isn’t visible here because it wouldn’t fit through the hole in my template. Don’t worry, I didn’t forget it.)

Same location, from inboard. This shows how the line is attached to the center section web to cross the fuselage, and then there’s a jog to get it to the proper location to exit the fuselage:

And finally, all the lines in place under the fuel selector valve:

Hopefully tomorrow I should get in my parts order from Van’s, which will contain the fittings I need to do the brake lines. I needed two more 90° bulkhead fittings for these lines; when I worked on them last night, it was with the knowledge that I’d only be able to have one line in place at a time. Once I have all the fittings, I can put everything in place at once. If I don’t get the order from Van’s, I can always go back to the rudder pedal assembly, since I got my #12 drill bit restock in today as well.

Well, I didn’t get a lot of useful work done tonight. I’d vaguely intended to muck around with the brake lines and/or fuel vent lines. I didn’t have the fittings I ordered for the brake lines, so I decided to look at the vent lines instead. I’ve kind of been on the fence about how to handle the vent line anyway. The “factory” method has the vent lines enter the gear towers, loop up as high as possible, and then exit out the bottom of the towers, just in front of the landing gear. However, some builders have been taking a different approach, as used by many F1 Rocket builders. That method is to simply bend a series of loops in the wing root and then have the vent exit out of the fairing between the wing and fuselage. This method is much simpler, though there’s speculation that it’s more likely to spit fuel overboard on the ground on a hot day.

Anyway, I’ve been going back and forth quite a bit as to which method to use. Tonight, I got to looking at the vent line routing, and noticed that the exit holes are prepunched in the gear covers. This tiny bit of information was enough to make me decide to do the factory vent line routing. So I measured, planned, cut, bent, and flared, and made my first vent line. I wanted to go ahead and cut the exit portion of the vent line to fit the nice JD Air vent pieces I bought a while back, so I was going to fit those to the gear covers – except they’d be covering one of the screw holes that attaches the gear cover. And the vent has to be installed before the cover. This seemed like a clear no-go, and a quick search of VAF confirmed the problem.

That left me with a pretty simple choice: use the factory routing without the nice vents, or use the Rocket-style routing with the vents. I decided to go with the latter. Tat meant no more vent line work – time to move on to the brake lines.

The brake lines are another interesting item. By the plans, the lines enter the gear towers through the middle lightening hole, but that hole is part of my removable covers. After doing some reading, I decided to add a bulkhead fitting to the gear towers, and split each brake line into two parts – one section from the cabin center to the exterior of the gear tower, and another running inside the gear tower. I’d been unsure of where to locate the bulkhead fitting, but my vent line decision gave me a nice spot – at the top of each tower was a prepunched hole, which would normally mount an Adel clamp to hold the vent line in place inside the tower. It was in a good location for the bulkhead fitting, so I got the unibit and opened each hole up for an AN bulkhead fitting.

Then I went to work bending the first line. I was quite proud of the results:

But then I realized there might be a problem. The tops of the towers are pretty narrow, and in addition to the length of the bulkhead fitting, I can only put a bend so close to the flared end of a line. I bent a piece of scrap line and flared it to use as a test, and the results were…displeasing:

Yup, that’s not going to work, unless I add some some chipmunk bulges to the forward side skins or something. So I basically have three alternatives here:

1. Reverse the bulkhead fitting. This would put the elbow portion inside the gear tower, so clearance in there wouldn’t be an issue any more. The downside here is that the bulky part of the run – the big 180° bend to the fitting – would be inside the tower. This wouldn’t be visible – this area sits behind the panel – but then that’s more stuff in what will probably be a crowded area. The good news is that after taking a look at the panel piers, I don’t think this will interfere with any major components.

2. Remove the bulkhead fitting entirely, insert a snap bushing, and run a single brake line instead of two. This wouldn’t take up a lot of space, but it would basically make it impossible to replace the line down the road. There’d be no way to extract it without cutting it. Though, if that happened, I could revisit the bulkhead fitting idea then. But if I’m going to eventually probably have to do a bulkhead fitting, why not just do it from the start?

3. Figure out a way to run a one-piece line through the upper lightening hole. I think this would be cumbersome and still difficult to replace down the road if necessary.

So that’s where I stand right now. #1 sounds like the best option to me, but I’ve already made enough ill-informed decisions tonight. I’m going to sleep on this one before committing to anything.

So, it turns out that bending hard lines is…somewhat challenging. I kind of knew that would be the case, but I was maybe a bit too buoyed by the first line I made a couple days ago. Suffice it to say that I made a lot of scrap material today. Still, I almost got all the lines done with the material I had on hand, but for one final annoying foul-up…more on that in a bit.

I started out trying to make the line between the fuel selector and the filter, which wasn’t exactly sensible, since the line between the filter and pump was going to be the annoying one, but I was kind of punting on that particular problem. Except I managed to foul up two attempts at the select-filter line in a row, for various and sundry reasons. Then, I oddly decided that maybe the filter-pump line was a better idea. And surprisingly enough, it went pretty well. I knew going in that I would have to flare at least one end of the line in place – the flares won’t pass through the snap bushings where the line goes through the gear towers. Fortunately, I didn’t have to do the actual bending in place; that would have been no fun at all. I actually got this one done on the first try; despite the annoyance of going through the tower, it’s a much simpler line than the other ones, with just two very slight bends.

Out of the filter…:

…through the tower…:

…and into the pump:

Next up was that pesky selector-filter line. This time I took a few moments to figure out the dimensions of the bends from my tubing bender – approximate radius and circumference. This allowed me to plan the line a bit better. A fun thing to consider while working on this is that the line from the right tank will be attached to the center section web in close proximity. To simulate the presence of that line, I put a length of tubing into a coupe of the adel clamps that will hold the actual line – this way I could be sure the two lines wouldn’t be rubbing or anything undesirable like that.

The finished selector-filter line:

Then there was the line to the left tank. Here, I took a few minutes and made a template from one of the forward side skins so I could approximate the passthrough hole for the fuel line:

The line here was pretty simple too; just down from the selector, a 180° bend back up to the passthrough, and a 90° bend to go through the hole. My previous note of the bend radius made this actually match up on the first try:

That only left one more line – the long one over to the right tank. Amazingly enough, despite my early mistakes, I still had enough tubing left to make this line. So I measured everything carefully, plotting out my first couple bends to get from the selector back to the center section web, did my bends, and…I forgot to subtract the bend radii. With the line against the center section, the end by the selector was at least 1.5” too far forward. I tried to salvage the line by adding some extra bends to account for the extra length, but it was too much – eventually I started to collapse a couple of the bends, and so I admitted defeat. This is the modern art masterpiece that resulted from trying to salvage that line:

So I’ll have to order some more tubing from Spruce this week. The good news is that this stuff is super cheap, like 75 cents a foot.

I wasn’t quite ready to quit for the day, so now what? I could either keep with the tubing-bending fun and work on some brake lines, or I could start paying with the rudder pedal assembly. The latter seemed like a lot more fun, so I started a full-fledged hunt for all the required parts. Rather than just jumping into the assembly instructions, I started roughly assembling the parts just to get an idea of how everything went together. But I could only go so far without having to final-drill some holes. I’d hoped to at least get the brake pedals in place so it looked like something…but they needed final drilling, So I just ended up with this:

The first actual assembly step was to final-drill the mounting bole holes in the slide bar to #12, so the assembly could be temporarily bolted into the fuselage. Well, I got exactly two holes drilled on the drill press; on the second one, the piece slipped, and the drill bit caught and promptly detonated. The part turned out OK, but obviously I needed a new drill bit. Oh, look – it turns out that was the only #12 drill bit I have. I had extras of literally every other size except for #12. Well, that pretty much put a stop to work on the rudder assembly – it seems that every hole in this thing is #12.

I tinkered a bit with the brake system, looking over the line layouts and gathering parts, but ultimately I didn’t really get anything done. I’m going to have to modify the line routing here a bit, so I’ve got to figure that out. The plans route the brake lines through the second lightening hole from the top in the gear towers – but that hole is in the middle of the removable plates I made. Having a brake line go through the would kind of put a kink in the whole “removable” thing. So I guess I’ll have to route the lines a bit higher and go down through the top hole.

Anyway, I’m going to sleep on that and give it a whirl tomorrow, I suppose. I’ve done enough damage for one day.

So yeah, it’s been a while again. I went for a track day at MSR Houston a few weeks ago, and during my second Sunday run session, I had a clutch failure in the car. After looking at part prices, I decided to replace the clutch myself instead of going to a shop – which kind of occupied a lot of my time. But the car’s back up and running now, so it’s finally back to work.

After reviewing the fuel system layout and considering the various lines that needed to be made, I eventually took the cop-out route and just made the easiest one first, the line between the fuel pump and the firewall fitting. Nothing too complex, just two 180°-ish bends, but the bend planes had to be about 90° apart to get things to align properly. And of course, the first flare I made, I’d forgotten to slide the B-nut and sleeve on the line first, so I had to cut it off. Good thing I still had extra tubing on the other end to work with…

Here’s the finished product:

I can already see that this is going to be a somewhat tedious process. The line between the filter and pump will probably be the worst; it has to pass through the gear tower, and from the looks of things, I’ll have to flare at least one end of it in place, which should be lots of fun…I may go ahead and deal with this line next, just to get the annoying task out of the way. I also need to fab up a template to help position the lines out to the wings. The forward side skins have a passthrough hole cut in them, so I’ll reproduce that in a piece of sheet I can cleco in place.

OK, not a lot done tonight. Tasks like this make me understand old sayings like “90% done, 90% to go.” Things move along pretty quickly when you follow the plans, but when you get to something where you have to figure things out yourself, it’s amazing how much slower you have to go.

Anyway, tonight I countersunk both mount brackets and riveted them in place. Next, I mounted the filter and pump in place, along with the fuel selector, then spent a whole lot of time staring at everything and trying to envision how the lines would be routed. One of the obstacles I ran into tonight is that I can’t find the adel clamps I need to use to route the line from the left wing across the cockpit to the fuel selector. There’s a bag with an assortment of clamps, but none of them are the right size. And reviewing the contents of the hardware bags, none of them list the proper clamp part number. I hate to make an order to Spruce just for four stupid clamps, but it may come to that. If I can’t find the things, I guess I’ll move on to tinkering with the rudder pedal assembly or brake lines or something like that.

Anyway, here are a couple photos; Here’s the fuel selector clecoed in place with the fuel filter clamped to the floor beneath it:

And the fuel pump clamped in place just behind the firewall:

I’m a bit torn about how to orient the fuel pump. Currently it’s mounted with the inlet forward and the outlet aft, so both lines would have to make 180° bends and sort of go the “long way around.” Doing it this way eliminates the concern of trying to carefully align the aft part of the pump with the prepunched hole in the tower that the line will pass through. It seems to me it would be challenging to get the line bent just right in that area. On the other hand, it means using an extra 2’ or so of tubing, and I don’t know how much excess is provided – and I’m sure I’ll ruin some lines along the way here. On the other other hand, it’s not as if it’s impossible to buy more tubing if needed…I dunno. I’ll have to keep thinking about it, I guess.

So today my package from Van’s arrived, containing my fuel pump and filter. In keeping with my previous decision, I’m going to focus on work with the fuel and brake lines (and anything else related to the forward fuse that I can think of) before closing things up. Before starting on the pump, I installed nutplates on the access cover holes at the tail of each aft side skin. I was supposed to do this before installing the skins, but I thought it would be easier to do with the skins on the airframe. I was kind of right and kind of wrong about that – while it was easier than dealing with a 10’ long skin draped on the bench, the entire tail wanted to move around while I was squeezing rivets, which isn’t conducive to great results. I ended up having to drill out and replace two rivets along the way, and this seemingly simple task took almost an hour.

Next, I got out the plans page for the fuel system and went looking for the required parts – a couple of mount brackets and hose clamps. It took me a while to track these down as well – it’s a whole lot easier to find large parts than small ones… The brackets are thick alclad and needed quite a bit of prep work; polishing outside edges on the bench grinder, filing down inside edges, and doing some ext a bending work so the bottoms of the brackets were flat. While working on the bench grinder, I had an unfortunate incident. I’d left my container of NAS1097 rivets on the band saw table, since it was convenient while I was riveting the nutplates. Well, I forgot about them, and with the vibrations from the bench grinder, the container walked right off the band saw:

I can’t decide whether I should just order a new assortment of NAS rivets or actually sort through this mess. On the upside, there are only six sizes to deal with…on the other hand, it would still be pretty unpleasant. So I dunno, maybe I’ll try sorting and see how long it takes for me to decide that I have better things to do with my time, like claw my eyes out.

Anyway, with the rivets in a cup for possible later sorting, I fitted the mount brackets to the forward floor and final-drilled all the mount holes. I’ll need to countersink these holes for flush rivets, which will probably be challenging due to the concave shape of the bracket…but it was late, so I quit before getting to that task.

Here’s the aft bracket, where the fuel filter will sit. This will be directly under the fuel selector, which is in turn just behind the left gear tower:

I need to do some test bends with my tubing to figure out what the circumference of the bends will be – that’s going to be necessary information when I start laying out the actual lines and figuring out all that fun stuff. I suspect I’ll be throwing away a fair amount of tubing along the way. Next time I should be able to rivet these brackets down and start doing some actual layout work.

So yesterday was pretty busy, and no work got done, but I made up for it with a productive day today. I started out by finishing up some miscellaneous tasks. First up were the rear rudder idler brackets. I bought a set of hole duplicators to help me drill these in assembly with the gear towers. The duplicators have two little arms; the first has a little nub that fits in the hole to be duplicated, and the second has a drill guide that sits on the other side of the part where the hole is to be duplicated. Since the arms are attached, both parts are kept in alignment, and you just slide the nub in between the two parts, then drill using the guide. Here’s the left bracket all set up for drilling:

And after final assembly:

While I was doing the idler brackets, I also final-torqued all the bolts in the gear towers and added torque seal. Next, I riveted the baggage ribs in place and added the autopilot servo mount brackets (after priming them):

Then it was on to the bulk of the day’s work, preparing the aft side skins. I skipped dimpling these previously, because they were stored in a kind of obnoxious location. I figured it’d be better to pull them out, get all the prep work done, and then just install them on the fuse when done. There’s an assortment of dimpling to be done here; there are of course tons of skin rivet holes, but there are also flush screw holes for the access plates (for the elevator control horns) and the rudder cable exit fairing. At this point, I also scuffed and primed a small area on the skins, where they’ll be visible inside the baggage compartment.

With the dimpling done and the primer drying, the aft mid longerons could be prepared. These were already countersunk, so all I needed to do was rivet a few nutplates for the baggage compartment access panel (which will, when removed, allow access to work inside the tail, a prospect I don’t look forward to). Once this was done, the longerons were back riveted to the aft side skins. Then I went and shot the final coat of paint in the previously-primed areas.

After a break to allow the paint to dry a bit, it was time to install the skins on the airframe. This is definitely a two-person job, since the skins are about 10’ long or so! Then there was just a lot of clecoing to do…

Here are the skins installed:

And a quick look at the painted areas inside where the baggage compartment will be:

I’ve been making a real effort to paint any visible parts prior to assembly, and I’ve done fairly, well, except tonight I realize the bulkhead where the mid and aft side skins join (visible at the left of the photo above) will need to be painted as well. I guess I should try and shoot that soon, before access gets any more limited – by which I mean before I install the aft bottom skin. The fun part will be trying to clean the bulkhead in place without wiping off any other paint…

Next, I get to continue with the tailcone. I may hold off on installing the large aft bottom skin until I finish all the work up front, just to help keep the fuselage from getting tipsy on the sawhorses (which might happen with the tailcone fully assembled). Hopefully my fuel pump and filter will come in this week, so I can get to work on fuel lines. I suppose I could go ahead and start working on brake lines, come to think of it.

Today I had lots of goodies come in from Aircraft Spruce. There was a set of hole duplicators, which I’ll use to drill those rudder pedal idler brackets up front, a tubing bender for when I get to making fuel and brake lines soon, and a pitch servo mount kit for the Dynon autopilot. I only bought the mount for the moment, for the sole reason that the servo is pretty expensive. The money I might have spent on the servo itself, I instead spent ordering a fuel pump and filter from Van’s, which I imagine should be here in the next day or so.

Tonight, I wanted to get the pitch servo brackets mounted. These are pretty simple, just a couple of extended angle bits that mount alongside the elevator bellcrank, which is in turn just aft of the rear baggage area. The servo will mount here and drive that bellcrank once everything is together. The first issue is that the angle pieces interfere with the bulkhead that’s located just aft of the bellcrank:

No big deal there, I just removed some material from the bulkhead to clear the angles:

Then I laid out a rivet centerline using the baggage rib angles as a guide, and marked my rivet locations:

And then finally clamped everything nice and tight and drilled the rivet holes:

I’ll want to prime these angle pieces before permanently installing them, so that’ll have to wait until this weekend. I’m also a bit curious about the attachment of the servo itself; if I’m reading the diagrams properly, it’s only attached to the angle bracket by a single bolt, which seems a bit sketchy. I’ll have to ask in the VAF forums and see if I’m missing something, or maybe this isn’t as big a deal as I’m thinking it is.

Anyway, that’s it for tonight…

I’d wanted to continue working on the rear rudder pedal brackets today, but that didn’t really work out. The idler brackets, which attach to the base of the gear towers, only have one prepunched hole; the other has to be drilled in assembly. This is kind of a problem, since the hole has to be drilled in a super tight spot. There’s no way to get an angle drill in there to drill in assembly, and I couldn’t even figure out a way to try and mark the hole – an option that I didn’t really like anyway, since it not only depends on the mark being accurate, but me accurately punching the center of the marked hole for drilling. I briefly tried to fabricate a small transfer punch for this, but pretty rapidly decided that I might as well just buy a hole duplicator set instead.

So I set the rudder pedals aside and moved on to installing the mid side skin assemblies instead. I don’t really need to worry about access for the rudder bracket any more, since the guide brackets are fitted, and they’re the only thing that would have been blocked by the mid side skins. Adding the skins was just a matter of doing a bunch of clecoing. I also had to move my sawhorses around a bit – initially, I had one just behind the firewall, and the other under the center section. But once I added the mid side skins and started clecoing, the fuselage became pretty well-balanced on the center section, moving around like a teeter totter while I worked. So I moved the rear sawhorse back to the rear spar area, and now everything is a lot more smooth.

Next, I riveted the upper longerons to the tops of the gear towers and the firewall angles. The gear towers were straightforward, as were most of the firewall angles, but it was a bit tricky when I got close to the firewall, due to limited access. I did mangle a rivet and have to drill it out, but that’s it. Here’s one of the firewall angle rivet jobs:

The next steps in the instructions were for assembling and installing the forward side skins, but I’m delaying those until after I’ve installed the fuel pump and filter, and fabricated the required fuel lines, and maybe done the hard brake lines as well. Bottom line, it’ll be a bit before I’m ready to close this area up. So I skipped forward to the addition of the tail cone. First step was to cleco the bulkhead at the aft end of the seat ribs into place, and then rivet to the outboard seat ribs. Then I riveted the baggage ribs and angles together, and clecoed them in place. Riveting these looks mildly cumbersome, though, and I was getting a bit tired, so I decided to call it a night at this point.

Once the baggage ribs are riveted, I’ll move on to dimpling, assembling, and installing the aft side skins, along with the rest of the tailcone. Then I guess I get to flip this beast over and get going on a whole lot of skin riveting. And of course, there’s still the matter of fuel and brake system stuff. But first, it’s time to place another Spruce order…

Fun aside: I was working with the garage door open today, and it was amusing watching people on the sidewalk staring in the garage as they went by. I’ve reached a point where it’s obvious that something unusual is going together in here:

And here are a couple more token photos of the current state of assembly: