Control System - FCP Pod - Magnetometer Mount

Busy weekend mixed with both "real" work and "plane" work. While I had some time to slip out into the garage, I was able to finish the control system by installing all the pushrods and control sticks for a clearance check with the fuel filter and fuel lines. With the straight fittings coming out of the fuel filters, it will be "close" in certain stick positions, so I'm going to play it safe and change them out for 45-degree fittings, which should make a pretty big difference. For photo purposes, I also grabbed my Tosten stick grips and stuck them on each side to get a first rough look at what the controls will look like:

Control Sticks installed with Tosten stick grips

Closer view of sticks and stick grips-- note clearance with R fuel filter

Of course, the sticks will have to be cut down quite a ways to be the proper length with these grips, but it was still pretty cool to sit in there and move them around a bit. The "trigger" button on the grip is normally wired as the push-to-talk button, but until that actually happens, we will refer to it as the "pew-pew-pew!" button. :-)

That was pretty much it for yesterday. Today, I started making a "pod" for the GMC-307 flight control panel. The master plan is to make a panel which measures approximately 9" x 2.5" and stand it off about 1.5" from the main panel, and contour it up to the top skin of the upper forward fuselage. The panel will fit (tightly) the GMC-307 control panel, as well as a custom annunciator panel with 4-5 warning lights on either side of the FCP. You may have seen pics previously of the mockup, where the GMC-307 is hanging down from the top... this is the general idea, but now I need to build a pod that actually mounts the thing in that location.

Unfortunately I didn't take any pics of the construction process (I was "in the zone") but here's a few photos of the finished product:

GMC-307 mockup and annunciator pod clecoed together

Back side of pod that will permanently rivet to the panel (and screw into the top skin)

Pod with front panel removed

Pod partially clecoed to the main panel

That's basically the idea of it! It all seemed to go together fairly well (although it took quite a long time to build), and with some upholstery over it I think it should look pretty sharp. We'll see. A lot of this is only visible in my head for now and hasn't yet been proven to work in the real world, so lots more to come on this.

In other news, I got started on making a mount for the magnetometer. It seems the consensus for mounting location for the GMU-22 is in the tailcone, along the top stringers and near the static ports. I again found myself on Justin Twilbeck's site and read up on the method he used to fabricate his ADAHRS tray, which he later changed to a place to mount the GMU-22 instead. Taking both of his posts (original design here and GMU-22 mod here) I made a tray similar to his first design but taller and with a few other modifications. Again, I failed to take pics of the construction process but here is the final piece:

GMU-22 tailcone mount

Basically, the tray is about ~3" down from the tailcone top skin, and the tray is approximately 10.5" wide. I cut a 2-9/16" hole in one side using a fly cutter (remember there is a center stringer in the tailcone) to eventually mount the magnetometer itself. The stiffeners are installed on the top side of the tray instead of the bottom also, for better clearance with the side plates. I made it so that the side plates each have an angle piece and two #12 holes, such that the mounting plate can be slid in on top and over the angle pieces, and then bolt into place with brass hardware. This way, the relatively weak non-ferrous hardware will only be loaded in shear, and should have no trouble holding the magnetometer in place. Cool! Now just for some primer and rivet the three individual pieces together.

That's pretty much it for the weekend. More panel planning, fuel system layout, and miscellaneous "stuff" to come!

Section 39 & 40 - Control & Flap Systems

So the brake and fuel lines are again on hold while I wait for more "stuff" to arrive, including the Loctite 567 thread sealer and a handful of fittings and miscellaneous hardware from Aircraft Spruce. While I was ordering stuff, I went ahead and ordered our ELT also (not to be confused with a BLT, which is a sandwich). We chose the ACK 406MHz model E-04. I'm still not sure if saying the brand name "ACK" out loud is supposed to be spelled out A-C-K or just saying the word "ack" in an angry, loud tone. Since an ELT's purpose is to transmit an attention-getting, loud signal in case of an emergency, I'm going to assume it's the latter. Either way, I am now a proud customer of one of their products. Anyway, it seems to be a popular model, and the price was right. We don't necessarily "need" the ELT yet, but I'm trying to spread out purchasing some of the bigger-ticket items month-to-month so that I don't end up having to buy a bunch of $500+ items at the same time. In my mind, it helps relieve a bit of the sticker shock that happens when you are... well... building an airplane. At $529, this item falls near the very bottom of that long list of bigger-ticket items on the "to-buy" list. Ugh.

Anyhow, today was a pretty straightforward day of making some good progress. I started out by finishing up my cleaning efforts organizing everything in the garage, in preparation for tomorrow's finish kit delivery (woo!). Then, while I still had a bit of time left I decided to prime, rivet and install the F-1063 idler arm that had previously been final-drilled and deburred in Section 39 page 6. It went together pretty easily and was a straightforward deal. Basically, Section 39 is now done as far as prep work is concerned; we just have to wait until the appropriate time to actually install and rig all of the controls.

Since there was still a bit of time left, I decided to flip the page over to Section 40 - Flap System. This section is pretty straightforward too, where you lay out the 5 torque tube and control arm pieces and drill them together. The first step was to attach the R and L torque tubes to the WD-1013A Flap Crank:

The WD-1013A Flap Crank drilled and bolted to the WD-1013C torque tubes

After that step, the next thing to do was retrieve the W-730 Bellcrank Jig for use in this section. The jig was shipped with the wing kit, and was used for rigging the ailerons. In a surprise twist of events, this jig is also now needed to "clock" the flap horns on each end of the torque tubes. It took me a bit to remember where I had stashed it, but eventually I found it in one of my parts bins. The plans call out to drill a hole in a certain spot to use for this next step:

The W-730 Bellcrank Jig with hole drilled as called out

This step was a breeze, because as it turns out, this hole had already been made at the factory. Thanks Van! The next thing to do was to bolt the jig to the flap horn and rig it all up so the horn sits flat on the table in the proper orientations:

The W-730 jig being used to clock the WD-1013B Flap Horn

The horn clocked to the proper rotation and slid to the proper distance (24-7/16") from the center crank

After drilling and bolting everything together on the one side, it was just a matter of repeating everything (mirrored) on the other side. Before long, we had a completed WD-1013 flap torque tube assembly... yay!

The next step was to make the four plastic bushings used to attach the torque tube to the fuselage itself. They are provided as four rectangular blocks with holes punched in them and must be trimmed to spec. The cutout along the top is mandatory, while the two cuts along the bottom are optional for a ~2oz weight savings. Hey, why not?

F-1030 UHMW Bushings, trimmed

That's pretty much it for tonight. Hopefully by this time tomorrow we'll have an undamaged and delivered finish kit here in the shop, ready to be worked on!

Interior Paint #2 - Section 39 Begin

Started off Saturday by stripping all the paint off the firewall, using a bit of Rustoleum "Aircraft Stripper" and loads of acetone on a paper towel. This was one of those lessons learned the hard way: Spend the time up front masking off the areas you don't want to paint so that you don't have to spend hours later on stripping it all off. Ugh. Oh well, in the end it all worked out.

All this paint stripping got me thinking: how much smoke really comes off the paint in the event of a fire? I've heard rumors that it creates thick, acrid, toxic smoke and can really make a life-or-death difference in the outcome from an in-flight fire. That was enough for me to take it seriously and strip it off. But, the engineer in me wanted to see exactly how much smoke comes off of this in a fire. So, I grabbed a scrap piece of aluminum that had been scratched beyond usability while installing the rear floor pans (remember my method for inserting them?). I had a love-hate (mostly hate) relationship with this particular piece of aluminum, so I was happy to spray it with some Rustoleum Hammered Black and take the torch to it. Here's what I saw:


It actually didn't smoke nearly as much as I thought it would! And the smoke didn't really have too much of an acrid or toxic smell. Not that I'd intentionally breathe the stuff, but it was a bit of a relief that it didn't blow up into a thick plume of nasty smoke or anything. Good data point, I guess. I still went through with stripping the paint off the firewall though, because it can't possibly hurt.

Once the firewall was stripped, I was able to mask everything again properly and spray another coat of paint in the areas that needed it. I went through the predicted two cans and left it to dry. Now... on to Section 39!

Whoa whoa whoa, Section 39, you say? What happened to 36-38? Well, I wanted to get started on the brake lines (36) but before I could do that, I wanted to make sure there would be clearance for the parking brake valve to go under (or at least near) the elevator control linkages, which are assembled in section 39. Additionally, section 39 is the first part I can actually work on and not need to be inside the fuselage, where the paint is still drying. So, off to make some aluminum control rods and brackets:

The F-1089 Elevator Pushrod

In total, I made three pushrods today: the F-1089 pictured above, the F-1090 mid-fuse pushrod, and the F-1091 pushrod that goes in the tailcone (plans in section 11 from the emp kit)... over 13 feet of pushrod in total! The next step was to final-drill and assemble the F-1063 Elevator Idler Arm, which unfortunately I didn't take any pictures of. It was a fairly straightforward piece to assemble. After that, I drilled the control sticks, which went fairly well too:

Drilling the control stick and pivot base

Not bad! Cruising right along in Section 39. Also, I was able to temporary-install the WD-1010 control column and figure out how much room there will be for the parking brake valve... looks like we'll be good to go for that! Will have to custom-make a mount for it and get it situated, will post pics of that later. Until then, more watching paint dry!

Aileron Actuation - Fuse Bottom Skins

Got another "to-do" checked off on the wing section today... yay! Finished the Aileron Actuation section today, which was a pretty cool section to work on. Previously, we had already created a few pushrods and bellcranks but not the torque tube assemblies, so it was time to get started on that:

Clocking/assembling the aileron torque tube assemblies - 5/16" offset and 17-3/4" total length (+1/32" acceptable)

One of the brackets needs to have a 5/16" clocking with respect to the other, as written in the plans. I decided to use a 5/16" drill bit (shown above) as my reference for clocking since it has a very precise "known" size. It went pretty smoothly and before I knew it I had two mirror-image torque tube assemblies. Now to prime and install on the wings. Installing them between the two torque tube bearings was actually was trickier than I thought it would be; there really isn't much room to work the pieces around, and the fact that the pieces have now been primed means they are even more reluctant to slip into one another. Eventually though, I prevailed and ended up with these torque tube assemblies installed:

R Aileron Torque Tube assembly

L Aileron Torque Tube assembly

With these installed, it was time to put the rest of the works together! This was exciting, because when complete you can push/pull on the levers here on the torque tube, and see the ailerons go up and down, way over on the other side of the wing... like magic! So, a few bolts/nuts/washers later, I had the following assembly together:

Torque tube -to- pushrod joint

Aileron bellcrank assembly with two pushrods

By golly it works! Awesome. Played with the ailerons, moving them back and forth for a longer period of time than someone my age ought to have. Oh well, no one was watching. We'll still need to final-rig these bearings at a later time for all the correct tolerances once everything is together, but they certainly appear close to the recommended clockings and everything moves smoothly and precisely! Very cool, couldn't be happier.

After Sarah got back from her afternoon plans (which included tearing up the skies over Marion in a C150, I might add), we got back to back-riveting the fuselage bottom skins. It's a fun process but gets pretty tedious after a few hundred rivets. We persevered through it all though, and I'm pleased to say that all back-rivetable rivets are now back-riveted! There's still a few dozen here and there that we skipped over to get later via the traditional flush-riveting method. Maybe tomorrow we'll get to that. No pics of the fuse in its current state yet, we're saving the "reveal" for when we get those last rivets done... hopefully tomorrow!

Aileron Actuation

Since we're simultaneously working on a few sections, why not start on yet another? Can't think of one good reason! :-)

While we're waiting for proseal to cure, we skipped ahead to section 23 to start on the aileron actuation section. This part of the plans involves constructing a series of pushrods, bellcranks, bearings and torque tubes that will translate pilot input to movement of the ailerons.

No pictures today either (I think we're getting lazy with the camera... need to change that) but basically we got through page 23-4 step 2, which means the four pushrods have been fabricated, as well as the outboard bellcrank installed. Still need to build the forward and aft torque tube assemblies, and clock everything together. We'll work this in as time permits, no huge rush on completing this section either.

That's about it for today, it was a relatively short day in the shop! Tomorrow if we're feeling crazy we might try and knock out the flap trailing edges and bottom skins, and see about patching the one small leak in the L tank.