Matt's RV-7 Project » Vertical Stabilizer

Misc stuff

Matt — Mon, 26 Mar 2007 01:33:54 +0000

I spent the whole day in the garage but didn't take many pictures. I guess I didn't actually get all that much accomplished – mostly I puttered and cleaned up the garage. It was great to be outside in the nice weather though.

One of the pre-tail-mounting chores I've been meaning to do is drilling the holes for the strobe and nav light wires that will go through the vertical stabilizer spar into the rudder. I picked the same location as Dan for much the same reasons – with the taildragger there aren't many other good choices for where to run these wires. I drilled a 5/16" hole for the strobe cable and a 3/16" hole for the nav light wires. Both holes are a little oversized so I can use a few layers of shrink tubing and some RTV to protect the wires from chafing.

Another day, another round of filling and sanding empennage fairings. I'm just doing a little bit every work session, fitting the glass work in between other tasks that are more fun.

I rearranged the garage a bit, and made a little table out of a sheet of plywood and a couple sawhorses. This is where the canopy is going to sit while I work on it. Yes, I've decided to work on the canopy some more before I put the airplane on the gear and mount the engine. Matthew convinced me that it'll be easier to get to it while it's down low and not high up on the wheels. Plus it seems to be warm enough these days to start thinking about working with plexiglass again.

I got out the canopy frame to make sure it still fits – yep:

Belt and suspenders

Matt — Fri, 11 Aug 2006 02:29:30 +0000

Back from a short vacation. We did a bit of rafting and a bit of hiking. Here's us on top of a mountain. It was very windy.

Just for grins, I called Van's and asked if there were any issues with the edge distance on the top two bolts versus the tailwheel weldment. Ken Scott said, roughly, "As long as you have any edge distance whatsoever it's no problem at all, but if you're a real belt and suspenders type of guy you could put another AN3 bolt in the middle." Belt and suspenders? Sign me up!

So here I've put an extra 3/16" bolt in there to help me sleep better at night:

Man, there's all kinds of stuff in there. Actually the whole tailcone is filled with dropped washers, nuts, clecoes, and metal shavings galore. After I get the empennage attach chores done I'll have to clean all this out.

Working on empennage attach some more

Matt — Sat, 05 Aug 2006 20:47:59 +0000

On an impulse, I bought this cool angle drill that was on sale at Brown Tool. I didn't get a chance to use it today though, since I need to replace the air fitting and it's really stuck on there tight. It'll have to wait until I reattach the vice to the bench.

I carefully positioned the F-781 forward spar attach plate so it was lined up vertically and on the centerline of the aircraft, then drilled it to the horizontal stabilizer spar. The vertical stabilizer spar is just floating there in this photo, it's not clamped or attached at the moment. You can also just barely make out the 0.032" shim I made to go between the plate and the spar, since there was a gap there. It's held in place with scotch tape in this picture.

I used a metal straightedge to make sure the aft end of all three rudder hinge points were in line, then I dropped a string down through the bolt holes just to double check. Small movements at the front end of the stabilizer have big effects back here in terms of getting the hinges to line up.

Once everything was good and lined up, I match drilled the holes in the attach plate through the VS spar, or at least as many as I could reach with the angle drill. I also drilled and reamed the pilot holes through the attach plate and HS spar up to 3/16".

I removed the stabilizer from the airplane to finish drilling the remaining rivet holes.

There is a tooling hole in the aft bulkhead exactly where the plans call for you to put the lowest of the three 1/4" bolts that attach the bottom part of the VS rear spar to the aft bulkhead and tailwheel mount. I center punched and drilled a #30 pilot hole right in the middle of that tooling hole, through the tailwheel mount.

Then I put the vertical stabilizer back on, bolted everything down, and back-drilled through the pilot hole into the stabilizer spar. Then I drilled the resulting hole up to 3/16" for temporary fitting.

I unbolted everything and took the stabilizer back off, then marked and drilled the other two bolt holes through the lower hinge bracket, using the dimensions on the plans.

Then I bolted the stabilizer back in place yet again, drilled and reamed all three bolt holes up to 1/4", and put some temporary bolts in.

Here's an inside view. There is acceptable edge distance on both of the upper bolts – I was worried about this – but they're a little closer to where the radius of the bent-up edges start than they probably should be. On the left side, I may have to grind down the washer a tiny bit to get it to lay flat. If I'd moved the holes inboard about 1/8" each from where the plans have you put them, it would have been perfect. This is okay though. This entire area has you measuring and drilling blind, so if it comes out halfway decent you've done about as good as you can.

This looks a lot like it did a few days ago, but now all the holes are drilled and the vertical stabilizer is actually bolted in place. This thing is completely solid – you can grab ahold of the end and give it a shake, and it won't budge. I suppose that's a good thing for a 200 mph aircraft.

I just have to deburr, prime, and rivet some stuff, then it can be bolted in place for good. Actually though, I will probably take it off again and just put some smaller bolts through the tailwheel mount instead. That way I can roll the fuselage around without the tail, to save space in the workshop.

But first, off to Colorado for a mini vacation.

Still working on vertical stabilizer attach

Matt — Tue, 01 Aug 2006 03:05:00 +0000

I measured about fifty times to make sure the vertical and horizontal stabilizers were absolutely perpindicular, then I drilled and bolted the up elevator stop to the fuselage and the VS spar.

I still have to fit and attach it in two other places, but this is a start. It's also all I have time for tonight!

Working on vertical stabilizer attach

Matt — Mon, 31 Jul 2006 02:49:18 +0000

Well, I got back from Oshkosh. Was busy working most of the time, but I did have a little time to sneak off and check out the latest gadgets. I also did some engine shopping. Anyway, tonight after the incredible heat subsided a bit, I spent a little time on the project. Here is the up-elevator stop prior to cutting:

Here it is all cut and with pilot holes drilled.

Here's the up-elevator stop being fitted to the aft fuselage. This piece is also one of the three places where the vertical stabilizer attaches to the rest of the airplane. I wasn't quite ready to commit to one particular stabilizer alignment yet, so I didn't drill the other set of pilot holes (from the elevator stop through the VS spar) tonight.

This whole process of fitting the empennage is very fiddly. Must go slowly to avoid building a crooked airplane.

Working on empennage attach

Matt — Mon, 24 Jul 2006 03:00:42 +0000

More work on the empennage attach chores today. I hauled the elevators down from the airplane storeroom, and spent a bit of time filing metal away from the left elevator where I noticed it was a little close to the outboard edge of the trim tab. Good clearance all around now.

Then I temporarily mounted them to the stabilizer. Hey cool, the tail has moving parts now!

The next step in the plans is to make the elevator pushrods. I cut them to length using my handy dandy miniature chop saw:

I had previously picked up a quart of this SEM self-etching primer, which is pretty similar to the GBP 988 I've been using elsewhere, just in liquid form instead of a spray can.

To prime the insides of the pushrods, I taped over one end, poured liquid primer down the other end and taped it up, and then sloshed it all around inside. Since these pushrods are so long, especially the aft one, using the liquid primer here was easier than spraying a ton of primer down the inside like I did with the previous ones.

After the insides were all coated with primer, I uncorked the ends to let everything dry out.

While the pushrods were drying, I got out the vertical stabilizer attach plate and clamped it in place to test the fit.

One of the first things the plans have you do when you begin the process of attaching the vertical stabilizer is to cut 5/8" off the VS front spar. Uh, gee guys, it sure would have been nice to have known about this when I was building the thing in the first place. It would have been a lot easier to trim the spar before it was, you know, all riveted in place and stuff. Further evidence that the RV-7 is a Frankenplane: Wings and vertical fin from an RV-8, fuselage and rudder from an RV-9, and instructions from who the heck knows where. Oh well, they fly nice and look real purty.

I got as far as clamping the vertical stabilizer in place before I had to knock off for the night. I'll be away at Oshkosh for the rest of the week, but it's nice to know that I have this thing-that-looks-a-lot-more-like-an-airplane-now waiting in the garage for when I get back…

Finished Vertical Stabilizer

Matt — Sun, 26 Jun 2005 00:56:51 +0000

Mary was awesome again and came out to pound in the skin-to-forward-spar and skin-to-middle-rib rivets:

Then the rear spar gets clecoed on…

…aaaaaaand, done. The vertical and horizontal stabilizers are finished, hooray!

Got the VS ready to rivet

Matt — Fri, 24 Jun 2005 02:17:31 +0000

I didn't get to fly as much tonight after work as I'd planned, so I got to work on the RV just a little bit. I swapped air connectors so I could run the rivet gun – as an aside, boy do I not like using the air tools without my handy swivel connector and my lightweight couplers – and smashed in the rivets that attach the ribs to the lower part of the forward vertical stab spar. Then, everything gets clecoed together:

I'll have to make sure to be extra nice to Mary so she'll be willing to come out to the sweltering garage to pound in these rivets this weekend…

VS spar riveting

Matt — Thu, 23 Jun 2005 02:02:26 +0000

I managed to find enough normal-sized air couplers laying around the garage to get the squeezer hooked up, so I was able to get the rear vertical stabilizer spar riveted together:

(Note that I keep an ample supply of lubricant available to make the work process go smoother)

The next step has you rivet the VS ribs to the front spar. I managed to get the upper and center ribs attached, but the geometry of the lower rib/spar interface has me stumped. I guess I'll either figure out a way to get the squeezer on those rivets, or I'll just smash them with the rivet gun. In that case, I have to wait for the new air fittings to arrive on Friday so I can get my regular air lines hooked up again and run the rivet gun.

Primed VS parts (again!)

Matt — Wed, 22 Jun 2005 02:00:55 +0000

Tonight I primed the replacement vertical stabilizer spar parts…

…and I also decided to lightly scuff and prime along the rivet lines inside the skin:

So I was all set to start riveting this baby together, when my Avery lightweight air coupler somehow came apart.

Of course one of the five little steel balls rolled off into a dark corner somewhere, so even if I could get the stupid thing back together, it probably wouldn't work right. Oh well, a new one is only six bucks, and I was going to pick up a few other things anyway, so back to the Avery website we go.