The Barn Find Build

[Eric Page]

Today I got the top of the vertical stab dialed in the way I want it...

IMG_1206.jpg IMG_1207.jpg

...then got to work shaping the first coating of filler on the elevator. I had to take off most of the SuperFil and a good part of the foam to get the profile somewhat close to the horizontal stab. They're not a perfect match, and they probably never will be, but once they're covered and color-matched I think they'll look just fine. This was the first time I had mated the two since installing the elevator's ribs, and I was pleased to see that the largest rib misalignment is only ~1/8".

Right side:
IMG_1208.jpg IMG_1209.jpg

Left side:
IMG_1210.jpg IMG_1211.jpg

That two hours of sanding was followed by mixing 40 grams of expired-but-free Hysol and slathering it all over the elevator tips. I guess that means more sanding tomorrow. Oh, joy.

IMG_1212.jpg

I finished up today by finishing the SuperFil on the door and window frame angles. I'm finally happy that I have smooth surfaces over the rivet locations, so they'll only show through a little bit, instead of enough to wear a hole in the fabric.

IMG_1213.jpg IMG_1214.jpg
IMG_1215.jpg IMG_1217.jpg

In other news today, I got a document from a local citizens' group that's opposing a major commercial expansion of the sleepy, rural county airport to which my home is immediately adjacent. This image shows the state DOT's rendering of the project; the red dot is approximately where my house is located. So, I've got that going for me...

AirportExpansion.jpg

[alexM]

LMAO! There must be at least 5 or 6 single engine aircraft operations per day at KTDO so of course it is ripe for a multi runway expansion and a terminal. Oh and a county with a population of at least a couple thousand. I mean, aviation is BOOMING right now so they need to get ahead of this. Maybe they can name it DB Cooper International since it's just north of where he jumped.

At my airport the port commissioner emailed us a survey with their vision of the future. It includes tearing down the rows of fully occupied T hangars and replacing them with 60' box hangars. The plan shows there isn't enough room to taxi a 59' plane between the hangars but that's just a detail. Oh and almost zero parking for cars.

They're pandering to the jet crowd because there are 5-6 business jet operations per week, so of course the hundred or so rent paying/fuel buying piston singles can GTFO. On the upside, they claim one phase is to develop the far side of the airport to put in 40' T hangars, a campground, a grass runway and fuel farm for planes on that side.

That will never happen. It is many millions of dollars they don't have and can't justify spending, and any previous attempts to develop that side of the runway meet with a lot of push back.

Included in their plan is the delusional expectation of self driving quad rotor air taxi service are right around the corner.

[Eric Page]

I've got news for you, my friend. TDO is only one of six airports on the state's short list, along with Arlington, Bremerton, Shelton, Paine and, yep, Tacoma Narrows!

[Eric Page]

Yesterday I got started on the rudder tip first thing, so the Hysol gluing on the foam block was able to cure by evening.

IMG_1219.jpg

When I got back to it later, I attacked it with the wood rasp, then 120-grit. Once it matched the shape of the vertical stab tip and was a tad smaller (to allow for build-up), I gave it a coat of Hysol and set it aside.

IMG_1220.jpg IMG_1221.jpg

In the meantime, I rasped and sanded the elevator tips to take down Hysol high spots, then gave them a skim of SuperFil to smooth out the divots. I'll sand those today and should have them finished.

IMG_1222.jpg

Since Oratex shrinks less than other fabrics, I'm dreading the sharp curve at the forward root of the vertical stab. So, I've been mulling my options for installing a razor back of some kind. I grabbed a 10' length of 1/2" Sch40 PVC conduit from the Kitfox aisle at Home Depot and hacked at it to see what I could mock up. I started with a long piece that went from the vertical stab all the way to the back of the turtledeck, but the forward half of it was basically laying flat on the spine of the fuselage, which looked silly. Then I shortened it and cut a notch in the end, placing it between the second rib in the vertical stab and the lateral tube at the aft end of the antenna plate.

IMG_1223.jpg
IMG_1224.jpg IMG_1225.jpg

I think that looks a lot better. Much to my surprise, with that much compression on the conduit it's really robust. I think with a couple of vertical supports from the steel structure below, the conduit could be a permanent solution.

Thoughts? Other than welding in 4130 tube, what have others used to form this feature?

[jiott]

For the razorback I've seen an aluminum tube with wood plywood supports.

[efwd]

Oratex is going to require some heat to activate the glue that you will use on that PVC. I don't believe that it will be suitable. Be careful heating up your tips while applying the fabric. Hysol gets soft and Foam is no match for the iron or high heat applied with the heat gun. Unfortunately, pressure is what is required, along with heat to get the glue to work as designed. Don't apply too much pressure or everything will collapse underneath.

[jrevens]

I agree with Eddie. My kit came with a curved piece of 1/2" aluminum tube and the plywood supports like Jim said. This was before the factory began to weld the curved razorback tube as a standard part of the fuselage. I did mine a little differently and my "razorback" curved tube is shorter than the normal one... that's because I located my antenna mounting plate further back. The longer it is, the easier it is to make the fabric conform to the curve, so it was harder to do mine than most of them.

[Eric Page]

Oratex is going to require some heat to activate the glue that you will use on that PVC. I don't believe that it will be suitable.

Hadn't thought of that. I think you're right; the heat would make the PVC soften and deform. Not a good idea.

Be careful heating up your tips while applying the fabric. Hysol gets soft and Foam is no match for the iron or high heat applied with the heat gun. Unfortunately, pressure is what is required, along with heat to get the glue to work as designed. Don't apply too much pressure or everything will collapse underneath.

Very good advice. Thank you.

[Eric Page]

I started out this morning working on the door frames again. I picked them up from the welder a couple of weeks ago but never got back to them again. I just had the welder plug up the holes along the center bar, and where the latch mechanism was mounted on the lower bar. I left the rest of the holes alone, as they'll be covered by the double-sided tape that mounts the bubble door plastic. Anyway, I ground down the welds so they're flat and smooth (sorry, forgot to take an after photo).

IMG_1226.jpg

With that done, I took them to a local sandblasting and powder coating shop to be stripped and re-coated. Would you believe $50 for both? Gotta love a little mom-and-pop business in a shed behind the owner's house. In the end, my investment in refurbishing the old frames will be $175 and about four hours' work. That beats the heck out of buying new.

Next I sanded the SuperFil on the elevator tips. They came out perfect, so I'm calling them done. Horizontal stab and elevator are ready to cover.

IMG_1227.jpg

I grabbed the wood rasp next and took down the high spots in the Hysol on the rudder tip, then put on a layer of SuperFil.

IMG_1228.jpg

Final item of progress today was a little work on the floor boards. As you can see in this photo, they got some reddish splotches on them somewhere along their journey, and I was only partially successful removing them with sanding. So, I decided to stain the plywood to cover them. I picked a Red Chestnut stain, which looked about as close as I was going to get to the existing splotches. Apart from one strange blob that appeared in the forward floor board, I think they look pretty good. Here's before...

IMG_1230.jpg

...and here's after two coats.

IMG_1238.jpg

With two hours between coats, I should be able to get two on the other side before bedtime tonight. Then I can make them smooth with 320-grit and get on with applying varnish.

The remainder of the afternoon was spent screwing with wingtips, but I've posted some questions about that mess here.

[Eric Page]

Nice progress today, but not many photos. I started out with the rudder while I waited for the heater to take the chill off in the garage. It needed two operations today. First was sanding down the SuperFil on the tip...

IMG_1250.jpg

…followed by bonding in reinforcements at the base of the fiberglass fairing. I don't know why, but on both sides the first builder cut almost all the way through the fairing edge, just above where it's relieved (much too far) for the control horn. I had actually broken the thin section of fiberglass that remained on the left side, so I cut and sanded two thin strips of wood (from a large tongue depressor) and stuck them in place with Hysol. They'll get varnished tomorrow.

IMG_1251.jpg IMG_1252.jpg

Once the garage warmed up a bit, I spent the rest of the day trapped behind a respirator, working on varnish. I'm going to pause here for a small rant:

It takes a very special kind of idiot to package poisonous, volatile and highly flammable chemicals in metal cans with spouts from which it is physically impossible to pour the contents without spilling them all over your work surface. Can someone please explain to me why we use this ruinously expensive, horrible s*** instead of buying $30/gal spar varnish at Home Depot?

Anyway... the markings on my mixing cups led me to prepare way too much varnish. I ended up with 16 oz, and tossed 10 oz of that at the end of the day. Once I had the varnish catalyzed and reduced, I put the first coat on one side of the floor boards, the bottom rib in the aft fuselage, the unpainted wood pieces that I used to mount the comm antenna, the new false ribs, all of the rib cap strips in both wings and the ribs in the new elevator.

I didn't take any photos of the varnishing since it doesn't look any different than the parts would otherwise. Lesson learned: use the ounce markings on the mixing cup and ignore the ratio markings to avoid a big waste of $180/gal material.