Matt's RV-7 Project » Elevators

Extended elevator stop

Matt — Sat, 14 Apr 2007 22:00:01 +0000

I wrote to Van's to ask their opinion of my elevator travel situation, and their reply was:

Matt,

You can either make a new elevator up stop or add a piece to the existing stop. The horns hitting the aft bulkhead is not a bad thing, but that will not happen when you fix the up stop.

Bruce Reynolds

Okay, I can do that. Since the existing elevator stop is already drilled for the bolts that attach the vertical stabilizer, I decided to leave it alone to avoid causing further problems. Instead, I created this little elevator stop extension out of some 1/8" angle:

It's riveted to the underside of the existing stop, using the existing three rivet holes through the stop and aft deck. It effectively moves the face of the stop forward about 3/32".

I also added three flush rivets to attach the other leg of the stop extension to the aft bulkhead. Probably overkill, but it makes me feel good.

Now to test the new elevator travel. Here's neutral:

Here's the new up position:

I now have 29.4 degrees of up elevator travel, which puts me in the allowable range of 25-30 degrees. I probably could have made my stop extension even a little bit longer, but as long as the elevator travel is within the okay zone I'm happy.

Empennage fairings part VI

Matt — Mon, 05 Mar 2007 02:00:19 +0000

I was either in class or studying for half the weekend, but I got a little bit done on the empennage fairings. I ground down the elevator tip fairings until I got the shape pretty much how I wanted it – they turned out not bad at all. I sanded them down to 320 grit once I got the shape right.

This is why I hate working with fiberglass – dust everywhere.

I removed the horizontal stabilizer from the airplane and laid it out on the bench to receive its fairings.

Trimmed the stabilizer tip fairings to fit and drilled and clecoed them in place:

The plans call for a minimum gap of 1/8" between the elevator counterweight and the fairing – mine is more like 3/16" in the neutral position, or slightly less when the elevator moves through its range of travel. Good enough. I did open up the other side a bit so the gap would be even on both sides of the stabilizer.

You can also see where I'll need to build up the outboard part of the stabilizer fairing to match the contour of the elevator.

I made some ribs for the stabilizer tips out of 3/16" balsa sheet. This reminded me a lot of how I used to build model airplanes as a kid. Actually balsa is really nice to work with. Maybe I'll take up model building again someday… nah.

I epoxied the ribs into the fairings and left them to dry overnight.

Since it was fairly nice outside, I decided to mask off the elevator tips and shoot a coat of primer. This will help me find the low spots and imperfections.

Not too bad. I got the look I was going for, and they turned out pretty nice. I will probably come back and do some more filling and sanding in order to work out a few minor imperfections, but overall I'm pleased.

Before I turned in, I managed to get the tail fairing nutplates riveted to the stabilizer.

All this work on fiberglass fairings, and this guy made his out of aluminum. I can't even comprehend the amount of skill that takes.

Empennage fairings part V

Matt — Sun, 25 Feb 2007 02:00:34 +0000

I decided on a new plan of attack for the elevator caps – I'll attach them permanently, but I'll make them look like they can come off. Then at least all the fairings on the tail of the airplane will have a consistent look, which is important if you're obsessive like me. First I rounded off the forward edges of the lead counterweight with a file, then I match drilled the untouched elevator cap and installed nutplates and reinforcement strips:

The two nutplates at the aft end are very close together. If I hadn't been forced to use the prepunched holes I would have staggered these a bit to avoid interference, as I did with the aftmost rivets holding the aluminum strips to the fairing. As it is I had to cut down some screws to keep one screw from trying to push the other one out.

Here's another thing that I'll do differently on my next airplane – when you dimple the attachment holes for the elevator caps, the rib flange gets between the dimple die and the skin and all your dimples end up with this little crease on the inboard side. You won't be able to see this once it's all painted, but if I'd known this I would have at least match drilled the fairings and dimpled these holes before riveting the elevators together.

Here's a test fit to make sure all the nutplates and holes are lined up:

I riveted a #10 nutplate to the outboard side of the counterbalance arm, using the 3/16" tooling hole that was already there. The reason for putting a nutplate here is that I can use it to bolt on a wide-area washer or two if it turns out that my elevator needs a little bit more weight up front… call it balancing insurance. Also, this photo is proof that I checked the torque on the outboard counterweight bolt on the right elevator – it will be inaccessable once the fairing is on for good.

Okay, I wasn't able to take pictures of how I performed the next series of steps, but I'll describe it and show the result. I mixed up a slurry of epoxy and flox, and applied a thick layer between the lead counterweight and the inside face of the tip fairing. This should glue the fairing to the lead and also fill in the gaps between them. Then I put in all the screws, and covered the edge of the skin with a layer of electrical tape. Next I mixed up a big batch of epoxy and micro, and used it to fill the gap between the skin and fairing on both sides of the elevator. I also applied a generous helping of filler to cover over the forward face of the counterweight, and the corners with the fairing and the counterweight come together. Most of it will get sanded off later, but this should hopefully provide the basis for a nice looking fairing closeout.

After all of the above was finished, I figured the right elevator would be out of commission for the rest of the day before the goo was cured, so I started thinking about the left elevator. It turns out that a replacement elevator cap is thirty bucks from Van's, so instead of throwing away the one I'd previously tried to put glass on, I spend some time sanding off my mistakes and restoring it to nearly-new condition.

Then I performed the same series of steps – match drilling, installing nutplates, and so forth. This photo is proof that I installed the spare nutplate and checked the torque on the inaccessable bolt on the left elevator

After all that (a couple hours of work) the left elevator cap got the same filler treatment:

Once both elevators are dry I'll start sanding them down. For now, though, I'm sick of composites.

Empennage fairings part IV

Matt — Thu, 22 Feb 2007 03:19:14 +0000

One more application of filler to the rudder cap – hopefully the last one, save for the inevitable pinhole filling. I'm really happy with the way the rudder cap has turned out.

I'm much less happy with the elevator tip I did the other day. I will probably throw this away and start over with a new one from Van's. The stupid counterweight is totally in the way, and it's looking less likely with every try that I'll be able to have removable tips on the elevators. Darn.

Here's the other, mostly untouched tip fairing, just to illustrate the situation.

Once again, I'm really glad the whole airplane isn't made of this crap.

Empennage fairings part III

Matt — Tue, 20 Feb 2007 03:07:00 +0000

Okay, so the first try at closing up the elevator tip fairing didn't turn out so well. I forgot to take a picture, but basically the fiberglass had nothing to adhere to (the lead was coated with tape to prevent sticking) so it was very wavy and uneven. Also, since I only used three plies of 1 oz cloth it was very flimsy.

One of the nice things about fiberglass is that if you screw up you can usually grind off your mistake and try again. This time I'm going to try using a piece of aluminum to provide the structural strength, and the fiberglass will just be there to hold it all together. I made a forward bulkhead out of some scrap alclad (0.040" I think), scuffed it up so the epoxy would stick, and temporarily attached it to the counterweight with double-sided tape.

Then I laid up three layers of 5 oz cloth, with a single layer of 1 oz cloth over the top to help fill in the weave. We'll see how this turns out.

I must say, the new style of elevator counterweight is a real pain. The old arrangement seems like it would allow you to spend a lot less time messing around with fiberglass to get the tip fairing to come out just right. But what do I know…

Back to the rudder, I mixed up another batch of micro and applied it here and there. This photo is kind of hard to interpret, but what you're looking at is a glob of micro applied to the front face of the rudder cap, with a piece of scrap alclad (covered with duct tape to make it non-stick) taped in place to make it cure with a nice smooth, even surface.

My cat wanted to help write this entry:

More empennage fairings

Matt — Mon, 19 Feb 2007 01:30:41 +0000

Today was an all-fiberglass day. Sorry, no action shots – hard to hold a camera with sticky fingers.

I sanded most of last night's primer off of the top rudder fairing, then put another glob of filler on the front where it still needs to be built up. My favorite tool for this kind of sanding is a 3" red scotchbrite disc in a die grinder turned down to low pressure. I also use a 60 grit sanding block where necessary, but power tools make the job go faster.

While the rudder fairing was curing, I got out one of the elevator tip fairings and started playing with it. The lead counterweight at the front is going to throw some sand in the gears of my plan to make removable empennage tips. It is tempting to permanently attach the elevator tips and just glass over the counterweights, but I'm still going to try to make them removable because I love a challenge. (Mary would probably say that I'm just plain stubborn)

I laid up three layers of lightweight cloth, sufficient to cover over the open end of the fairing where the counterweight lives. It's not much to look at right now because the peel ply is blocking the view. Underneath is a layer of electrical tape to prevent the fiberglass from sticking to the lead. With any luck this will form the starting point for a closed-end fairing that will cover the counterweight but will still be removable – we'll see tomorrow.

Hours later, the second coat of filler on the rudder was dry, so I proceeded to sand away at it. The shape is almost there now – just needs one or two more layers.

After shooting a coat of primer to help me check the finish, I put more filler on a few spots to fix some of the more egregious pinholes. My goal is just to get the basic contour correct – I'll leave the detailed surface finish work to the painter.

In the middle of all this, I bought and put together this particle board file cabinet for Mary. I found myself thinking how awesome it would be if airplanes were put together with quarter-turn fasteners. I'd already be flying!

Worked on pitch controls

Matt — Mon, 04 Sep 2006 23:22:56 +0000

Not much got done on the airplane today because I was tired. However, I did figure out what was wrong with the F-789 forward elevator pushrod… it's not that it was too short to allow sufficient down elevator travel, it's that the control column was hitting on the seat ribs. I dremeled out some small bites from the F-716 seat ribs, just enough to allow full forward stick plus about 1/16" extra for clearance.

Another photo of the other side. The duct tape is to protect the finish on the control column.

I likewise had to trim the removable parts of the two center seat ribs:

Once I had full stick travel, I put in the pilot's stick and seat in order to adjust the neutral stick position. Man, these seats are comfortable as heck.

Here's me doing ergonomics testing. I was in and out of the fuselage a half dozen times before I got it the neutral point adjusted where it fell easily to hand. The pushrod has a little more than the minimum required thread engagement, which is good. If you're reading this and you haven't fabricated your F-789 yet, do yourself a favor and make it about 1/4" longer than what the plans call for.

Yes, I made airplane noises:

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…

Mounted the horizontal stabilizer

Matt — Sun, 23 Jul 2006 03:24:37 +0000

I was going to work on the brake lines some more today, but I didn't receive all the parts I ordered earlier this week – one box of AN fittings from Wicks got shipped to the wrong address and subsequently lost. Kudos to the Wicks people, though – they were able to help me figure out what happened and get a replacement order on its way, at no charge – on a Saturday. Everybody go give Wicks some business, they deserve it. Even if you don't need any airplane parts, they're having a sale on toy gliders, and who doesn't like toy gliders? Nobody, that's who. If there are any such people I refuse to accept it.

Anyway, so not enough parts to work on the brakes. The only things left in the fuselage plans are mounting the wings, which I already decided not to do yet, and mounting the tail. Okay, let's mount the horizontal stabilizer today. I dug out the HS and elevators from the storeroom and rigged them on the bench to make sure everything still fits:

Somehow, the bottom of my left elevator has developed this mysterious dent. I'm not sure what caused it. At least it's on the bottom surface – it will probably eventually be joined by more little dents as rocks and stuff hit the bottom of the tail when the tailwheel is on the ground.

I clamped both elevators exactly in trail, to align everything for the drilling of the elevator control horns.

Some people have trouble with their elevator horns not lining up very well. They're welded individually, so it's likely that there will be some misalignment when you bring the two elevators together. Mine were almost exactly identical, though, which is good.

The left horn was just a fraction of an inch forward of the right one, so the left elevator was the one to get the first hole drilled in it. I took the elevator back off the stabilizer to make sure the pilot hole for the pushrod bolt was in the right spot.

With everything back together again, I measured the distance between the two faces of the control horns at the approximate location of the bolt hole…

Then I made a simple drill jig out of a sandwich of 3/16" birch plywood squares glued together, with a hole drilled perpindicular to the face with a drill press. This got clamped between the elevator horns, and then I transferred the pilot hole across to the right elevator horn. You have to do it this way because you don't want the bolt that joins the two elevator horns to the pushrod to be crooked.

I drilled and then reamed the pilot holes up to 3/16", then trial fitted a bolt. Yep, I'd say that's straight all right.

Next I made the F-798 shims, which go between the HS mounting flange and the aft fuselage deck. This photo makes them look like they're not the right shape, but they are – must be the camera angle.

I had to rearrange the garage to let me fit the horizontal stabilizer onto the fuselage – then, I clamped it to the aft fuselage and measured, measured, measured until I got everything lined up and straight. To help make sure the stabilizer was exactly perpindicular to the long axis of the fuselage, I drilled a hole in a tape measure; by clecoing it to one particular rivet hole on either side of the firewall and pulling it tight, I was able to measure the distance from the firewall to the stabilizer tips without anyone around to hold the other end for me (important tip for those of us building mostly solo!).

I tweaked and tweaked until both sides measured exactly the same – 156 3/16" in this case. The hole in the tape measure was right at the 1" mark, by the way.

There are four bolts that hold the forward HS spar to the fuselage. The two outboard ones are a real pain – each of those bolts has to go through five or six layers of stuff, which means you have to do a ton of very careful measuring to make sure that that one hole has adequate edge distance on every part it goes through. Here's a view of the underside of one of these areas, where the bolt has to go through the longeron, a spacer, and an angle (and then the aft deck, the F-798 spacer, and the forward HS mounting flange). Of course, the quickbuilders also seem to have cut the F-710B angle a little bit short on my airplane, reducing the margin for error even further. By the way, you can't actually see any of this stuff inside the fuselage – I had to use an inspection mirror and take lots of photos like this in order to get an idea of how things were going to work out. Thank goodness I have a small camera…

After lots and lots of measuring, I got out the drill and made some pilot holes for the outer forward holes. Hooray, they both came through right where I wanted them. Here's a view of the right side – the left is similar:

I drilled and reamed the holes up to 3/16", then put some nuts and bolts in. You can see the shims in place there – I decided to ignore the part where the plans tell you to drill the stabilizer to the fuselage without the shims in place, and then put the shims in and match drill the holes. It seemed like it would be easier just to clamp the heck out of everything and drill all the parts all at once, which is what I did. Everything looks good here.

Much measuring later, the other pair of bolts are in. To properly locate these, I had to take the stabilizer off and measure, but I'll spare you the boring details.

Here's a view of the nuts on the left side:

After lots more measuring, here are the other four bolts that hold on the rear stabilizer spar. I used a 3/16" drill bit as a spacer between the rear spar and the aft deck, as suggested by the plans. This puts the stabilizer at a 0° angle of incidence with the aft deck and longerons, which I verified through careful measuring. None of the hole locations on this end of the stabilizer are marked for you either, but at least you can see what you're doing a little better.

Careful measuring pays off – the bolts are centered vertically on the stabilizer reinforcement bars, and almost exactly on the centerlines of the stabilizer mounting bars. Acres of edge distance everywhere.

It's kind of starting to look like an airplane!

Not shown in the above photos are the hours I spent getting things lined up, taking the stabilizer off to mark something, measuring another dozen times to line things up again, etc. You only get one chance at this so I wanted to make sure that everything was as precise as I could make it. Fortunately, It all seems to have turned out pretty well.

Elevator center bearing

Matt — Sat, 15 Oct 2005 02:36:23 +0000

Here's what 12 bucks plus shipping gets you from McMaster-Carr. Actually, their site was a breeze to navigate and their shipping was both prompt and reasonable, so I can't really complain.

Unfortunately, this drill bushing was just a few thousands too big to fit through the elevator bearing. I was going to schmooze some time on my friend's metal lathe, but then I figured out that hand drill + belt sander = poor man's lathe. I just chucked the bushing in the drill and held it up to the belt sander, and turned it down into a sort of bullet shape that fit snugly and centered-ly in the elevator bearing. Then I chucked it in the drill press and turned it against some emery cloth to smooth out the surface again so it wouldn't get stuck.

The first elevator gets put on the stabilizer with Avery's temporary pins, and it's held in trail by clamps on the counterweight arm. Then the drill bushing gets inserted in the center bearing, and the pilot hole is drilled right through.

Then the pilot hole is enlarged in steps up to a C size drill, and then reamed to exactly 0.250 inches.

Hooray, a bolt through the bearing fits right through the new hole and the elevator pivots perfectly.

The above process is repeated for the other elevator, and now the center pivot is complete.

Now all I have left to do on the tail (other than fiberglass, which I've decided to save until later so I can do all the obnoxious itchy stuff at once) is tighten up the rod end bearings on the elevators, install and tighten the corresponding ones on the rudder, and play with the trim tab linkage a bit.

Installed elevator trim servo

Matt — Thu, 13 Oct 2005 01:50:45 +0000

Tonight I finished installing the elevator trim servo motor. I had to cut the pushrod to length and install the clevises, and then with the help of a drill battery… it's alive!

This is the first part of the airplane able to move under its own power. I'm stoked. (do the kids still say "stoked"?)

I had to enlarge the aft end of the notch to clear the pushrod when the trim tab is in its full up position (full nose down trim). I may need to file it out a little more later, but this is okay for right now.

Here's a shot of the attach hardware, just to remind myself that I did install the cotter pins.

Elevator hinges

Matt — Mon, 10 Oct 2005 00:57:26 +0000

The in-laws were in town so I didn't do any work on Friday or Saturday, but today I was able to spend the afternoon out in the garage, building airplanes and enjoying the nice weather. I rolled the leading edge of the right elevator as best I could, and since I figured I'd have a similar puckering problem on this elevator I went ahead and doubled up on the rivets for the middle and outboard sections while I still had it clecoed together:

That made it turn out pretty nice. I think the problem with the elevators is that the skin is too stiff and the spar is too narrow at the tip to get a nice bend out there; I probably also could have used a smaller-diameter broomstick and gotten better results. It turned out acceptably though:

Then I hauled the horizontal stabilizer out of storage, and went to work getting the elevator hinges set up:

I used Avery's temporary alignment pins to hold the elevators in place while I worked – way easier than putting bolts in and out. I must have had the elevators on and off a half dozen times today, and these pins made the job a lot simpler. I also used Avery's rod end bearing installation tool to (surprise) install the rod end bearings, although if I'd been feeling industrious I could have made my own out of PVC. I don't actually remember ordering the Avery one, but I found it in my toolbox so I must have been planning ahead during some previous tool-buying spree. Or maybe it was the tool fairy…?

Behold the newest addition to our country's military arsenal – the F/A-RV-7 Stealth Attack Geo!

Here is another shot, this time with the wings folded for supersonic cruising flight!

The elevator counterbalance arms were way too long to fit the cutout in the stabilizer skin – I think Van's must have changed the elevator design at some point without changing the HS to match, because I've read about this problem happening to a lot of builders.

I trimmed about ³/₄" and now everything fits together. This will be cleaned up and deburred after I take the elevators off again.

I also had to notch the lower flange of the HS spar, per the plans, to clear the elevator horns and allow enough down-elevator travel.

Here's the HS with both elevators temporarily attached. This thing is huge – over eight feet wide. Sweet.

Finished left elevator leading edge

Matt — Fri, 07 Oct 2005 02:06:29 +0000

I had a little time after work tonight, so I finished the leading edge of the left elevator. Here it is, completed, sitting on the floor in the unused bedroom we call the "airplane room":

I didn't like the way the skins were puckered up between the rivets in some places, so I doubled the number of rivets in the leading edge along the middle and outboard sections. That made the skins lie down and look nice.

Built new left elevator

Matt — Mon, 12 Sep 2005 02:12:49 +0000

This weekend I went nuts on the left elevator and got it 95% completed.

One of the first things I did with the new elevator skin was to cut off the little flaps that Van's wants you to fold down to close out the trim tab area. Instead, I made this little stub rib out of scrap 0.020" to close out that area. I elected to orient it with flanges facing inboard so I could squeeze some of the rivets. If I had it to do over again, I would stagger the rivets on the upper and lower surfaces so they wouldn't line up quite so exactly – that might have let me get the squeezer in there to squeeze one more of them. As it was, I ended up using three AD3's and three MK-319-BS pop rivets to hold this guy in place. It worked out very well and looks great in the finished version.

Here the left elevator parts are resting after being primed (trim servo brackets, interior rivet lines within the skin) or getting some primer touch-up (ribs, spars, etc). The old stiffeners got riveted to the new skin with nary an oops rivet to be found.

Here the left elevator skeleton is complete and ready to be installed in its permanent home. Right after I took this picture I put the required blobs of blue RTV at the trailing edge of the four full-length stiffeners.

Here's a dorky shot of me looking tired, standing next to an almost completed left elevator. Gotta prove to the feds that I built this thing myself.

The only things left to do to the left elevator are to rivet on the trim tab hinge and affix the counterweight permanently in place… oh, and roll the leading edge… and, install the fiberglass tip… and…

In other news, two guys from work have each ordered an RV Training Kit for themselves, and are going to eventually bring them to my little aircraft factory for a hands-on tour of basic sheet metal construction. It should be a fun time. Too bad it will cost them each about $70k before they're finished. Muahahaha!

New elevator skin arrived

Matt — Thu, 08 Sep 2005 14:11:35 +0000

The new elevator skin and some other misc. parts (extra rivets, etc.) arrived today. I got as far as doing the soldering iron and ruler trick to remove the blue plastic along the rivet lines before I had to call it a night.

Trim servo bracketry

Matt — Wed, 31 Aug 2005 01:45:30 +0000

Back on the horse… tonight I did the fabrication and so forth on the elevator trim servo cover plate and the brackets that attach the trim servo, and got them ready for priming.

Total parts ruined this evening: Zero (woohoo!)

Elevator tab bending

Matt — Sun, 28 Aug 2005 18:05:14 +0000

So here's the message I posted to the VAF forum earlier today:

Okay, mostly I just want to vent right now. @#$% tabs on the left elevator skin!

I did the wood block thing and I thought it turned out "okay" – not cosmetically great, but acceptable. Then I looked at it closely and saw the big (5/8") crack in the top side, right at the trailing edge. It seems the length of the little flaps you bend to close out the skin in the trim tab area was too long – I trimmed them up some, but apparently not enough – and the bottom tab dug into the top skin, the pressure of which caused it to crack as I was going over it with the rivet set to flatten out the bend.

The crack is too big to live with, and I don't want to have cracks in my airplane anyway. It's also too deep into the skin to just cut it off and replace, so now I am drilling out the rivets that hold the elevator stiffeners and other stuff to the skin, and I'll order a new skin from Van's tomorrow. Sixty bucks plus shipping, ouch.

This next time around, I'm going to be smart and ignore the instructions – my new plan is to use the hand seamer to make the elevator tab bends first thing, before I complete the trailing edge bend. Or, maybe I'll fabricate a little rib to put in there instead. At least I'll have plenty of scrap aluminum available to use!

I think I'll also do the trim tab the same way, because this wood block and folded tab stuff is completely lame. I wonder why Van's doesn't just offer a little rib to put in there… I know from searching various list archives that I'm not the only one to have trouble in this area. Yet another aspect of this airplane project that makes no sense, I guess. It seems like the times when I've gotten into the most trouble with the empennage so far is when I've done exactly what the plans say and in the prescribed order, instead of throwing them out and using my head instead. I wonder how many fuselages I'll have to build before I get it right? Grr.

Okay, rant over – thanks for listening…

mcb
RV-7 emp
QB wings & fuse scheduled for October

http://www.rv7blog.com

So, here's the carnage that resulted after I drilled out every single rivet that was holding on the left elevator stiffeners and trim mounting plate. It went surprisingly fast, and I didn't really wallow out any of the holes, so I won't have to use very many oops rivets, if any. I don't recommend this as a way to practice drilling out rivets, however.

Left elevator progress

Matt — Sun, 21 Aug 2005 22:45:10 +0000

Today I deburred, dimpled, countersunk, and mostly primed the left elevator parts. However, I ran out of primer when I was almost done, so I'll have to wait until the case I ordered last week shows up. Nothing worth photographing – just look at the photos of the right elevator parts after priming and imagine them flipped 180 degrees.

Oh, one other thing I learned today: A side grip cleco will make a nice blood blister if it pops off the pieces it's clamped to and bites your finger instead.

Left elevator work

Matt — Tue, 16 Aug 2005 02:31:50 +0000

Tonight I got the left elevator clecoed together and mostly match drilled before I had to call it quits:

Riveted right elevator

Matt — Mon, 15 Aug 2005 02:00:53 +0000

Today was a productive day. Let's walk through it. First I riveted together the right elevator tip ribs:

Then I got the elevator skeleton (tip ribs, spar, hinge points, root rib, horn weldment) riveted together:

Then the counterweight skin gets riveted to the elevator skin with two rivets on top and two on the bottom. This makes sense if you look at the plans – these rivets would be impossible to squeeze once the spar and ribs are in place, so by putting them in now you get to avoid the use of blind rivets here.

The skeleton is stuffed into the skin, and it starts to look like a control surface:

Blobs of RTV (the non-corrosive kind) are put at the trailing edge where each pair of stiffeners comes together. This supposedly helps reduce problems with cracked trailing edges from the skin flexing around the stiffener ends.

Then all the remaining rivets are put in, and the right elevator riveting is complete!

I ended up using two blind rivets at the trailing edge (one on the top side at the tip, and one on the bottom at the root) where the ribs are so narrow that it's impossible to get any kind of squeezer or bucking bar in there. Matthew had previously loaned me a special back rivet set that looked it like it might have helped with those rivets, but I couldn't get it into my rivet gun – the shank was too big. I've seen on various websites where people have made special bucking bars by grinding up axe heads or chisels or whatever else, in a quest to avoid using blind rivets here, but even I'm not that obsessive – put in the poppers and move on, I say.

The last step of the night was to torque the nuts that hold on the counterweight. A dab of torque seal compound marks each nut as being properly torqued, and lets me inspect it later on to see if it's come loose.

I probably used too much on this nut, but it was an old tube of the stuff and it kind of blew its top when I opened it. Oh well.