skeleton | Andrew's RV-7 Build Log

Drilled Right Wing Ribs to Main and Rear Spars

September 29, 2010

Tonight, I drilled all of the right wing main ribs to both spars. Not a lot of commentary, so I’ll just get to the pictures.

After drilling the middle two rear spar holes for each rib, I moved the clecos into those holes and matchdrilled the upper and lower holes.

Rear spar, looking forward.

Same with the front (although the clecos are in front of the main spar here).

You can just barely see the clecos in the 2nd and 3rd holes of each rib.

Also, I have a question about some of the flange-to-flange holes. Here’s what I wrote on the forums:

Hello everyone.

I was working on drilling my main ribs to the main and rear spar last night, and the instructions say “drill all of the rib to spar attach holes.”

Then, they have you take everything apart, deburr, prime, and then rivet the ribs to the spars.

What should I do for the flange to flange holes? (Circled in green below, but there is one more on the ribs for the lower rear spar flange).

If I leave them as is now, I’ll be match-drilling them with the skins later, but then I won’t be able to deburr the holes (because the ribs are now riveted to the spars).

I could run a #40 bit through all of these holes and deburr before assembly. (I could also dimple the rear spar ones, since they will eventually be dimpled to accept the skin dimples.

Any thoughts?

Thanks in advance.

Here's the same picture, but smaller, with green circles.

We’ll see what they say.

Here's a better angle.

Then, I pulled off the rear spar.

(What a sad moment. I have had this clecoed together for a week or so, and every time I go in the garage, there’s a wing! How cool is that? Now, I’m back to rib deburring (or catching up on the left wing). Not as exciting as a wing skeleton.)

After taking the rear spar off.

Everything taken apart for the night.

I can’t believe that took me an hour.

Prev | Next

Leave a Comment » | Wings | Tagged: Clecos, Drilled, main ribs, matchdrilled, skeleton, spars, Wing | Permalink
Posted by Andrew

Preparation for Left Elevator Skin Riveting

July 21, 2010

Prev | Next

Now that my #10 dies are here, I can proceed with the counterbalance skin and preparation for riveting.

This is how #10 dimples are supposed to look.

No cracks!

After beveling the exterior of the counterbalance skin, drilling the two fairing attach holes (that will be doubled up with the elevator skin) to #28 and dimpling to #6, I threw the counterbalance skin and the little trim riblet up on the priming table, opened the garage door, got the respirator out, and shot these two with primer.

Primed.

After that was done, I clecoed the counterbalance skin in place and riveted the two rivets on each side that can’t be reached after the skeleton is inserted.

There's a nice lap joint there that could have used some edge-rolling, except I FORGOT TO EDGE-ROLL, EVEN THOUGH I JUST BOUGHT AN EDGE-ROLLING TOOL!

The two rivets in question on the top.

Nice shop heads.

And two more on the bottom.

Then, before inserting the skeleton, you loosely place the counterweight in position and partly insert the two screws.

Okay...

Then, I riveted the little riblet I made to the trim spar.

Skeleton, ready to be inserted into the skin.

Closer look.

Of course, I then realized that I needed that area open so I could attempt to buck the four rivets outboard of that point. Drilled out that rivet.

At least I remembered to put some RTV along the back edge of the stiffeners.

After that, I got the skin clecoed on.

It's looking like something that slight resembles an airplane!

Another angle.

I’m kicking myself for not edge-rolling that one lap joint. I only remembered that I didn’t when I woke up in the middle of the night. My two options are to leave it, or drill out 4 rivets and edge roll. Maybe I’ll rivet the rest of the joint (two more rivets), then decide whether it is bad enough if the edge picks up at all. I don’t think it will, but I’ll start there so if I have to take it apart, it will only be a few rivets.

1 hour. 4 rivets, one drilled out.

Prev | Next

Leave a Comment » | Empennage | Tagged: #10 dies, #6, clecoed, counterbalance skin, edge-rolling, riblet, Riveting, RTV, skeleton | Permalink
Posted by Andrew

More work on the Counterbalance Skin

July 20, 2010

Prev | Next

Things have been slow with the airplane recently, right? Well, after a few weeks of letting the garage slowly spiral into a mess of hall closet items (while I’m redoing the floors), saw dust (while I’m redoing the floors), and aluminum dust/shavings (I am working on the plane a little), I decided it was time to get things cleaned up. After an hour of cleaning and organization, I snapped this picture of a nice clean workbench and floor area. Doesn’t really do it justice, but something about a clean workbench makes me happy (notice how I am not showing you a picture of my second workbench!)

(Don't tell the girlfriend I had the vacuum cleaner up on the table going back and forth. It works pretty well, but I accept no blame if you try this at home.)

Okay, finally on to the project. My replacement E-713 came the other day. instead of trying to cleco it on to the already-dimpled skeleton and matchdrill, I am going to trust Vans’ pre-punches and just run a #40 bit through the appropriate holes before deburring and dimpling.

After that was complete, I taped the outside of the skin that I want to protect from primer and scuffed everything up.

Ready to prime...almost. I'm still waiting on a #10 dimple die from Avery. Should be here any day.

Because this part of the exterior side is under the main left elevator skin, I'm going to prime it. Those two smaller holes need to be drilled to #28 before dimpled for #6 screws.

After that, I grabbed my two trim tab horns, and deburred, scuffed, and dimpled the flange holes.

I still need to trim these down per the plans for the electric elevator trim, but I also haven't ordered my electric elevator trim kit yet.

Finally, I disassembled the trim tab to get a little start on that. Here’s the spar, deburred, scuffed, and dimpled on the bottom flange.

The top flange (on the left side of the picture) needs to be countersunk for the upper trim tab skin, because the hinge sits just below the flange, and can't accept a dimpled flange.

2 hours in the shop today, but only 1 hour counts as build time. Hooray clean shop!

Prev | Next

Leave a Comment » | Empennage | Tagged: #10 dimple die, #40 bit, aluminum dust/shavings, Avery, cleco, countersunk, dimpled, E-713, electric elevator trim, flange, left elevator skin, primer, scuffed, skeleton, trim tab horns, vacuum cleaner, Workbench | Permalink
Posted by Andrew

Left Elevator Counterbalance Skin

July 13, 2010

Prev | Next

A short half hour tonight. First thing was to grab the primed end ribs and get them clecoed to the left elevator spar. No problems there.

Looks good. Ready to rivet (but not tonight).

Next, I need to get the counterbalance skin taken care of (must be riveted to the skin before the skin can be riveted to the skeleton).

You can see I clecoed it in place and drew a line where the two overlap; I'll use this as my primer line.

Then, I realized I’m going to have a hard time deburring, dimpling, and scuffing with the blue vinyl on. [sigh] Off with the vinyl, re-cleco, redraw my line, then back off to deburr, dimple, and scuff.

After dimpling with tank dies where the skin sits under another dimple, and regular #40 dies where it doesn't.

While I had the #6 dimple die out (I’m attaching all fairings with screws for now), I moved over to the elevator skin and dimpled there, too.

Make sure you drill all holes that need to be dimpled with the #6 dies to #28 drill. This is slightly larger than the #30 you are used to.

Again (for the search engines), the correct drill bit size for a #6 screw and #6 dimple die is #28. Ask me what happens when you dimple a hole that isn’t drilled to the right size. (Hint: the same thing that happens when you overdimple using something other than a dimple die because you are too cheap to buy a #10 die…see below…)

Okay, back to the counterbalance skin.

These are dimpled to #8 (I don't have a #10 dimple die). last time, I used a punch set (with a little rounded lip on it) to enlarge the dimples to the equivalent of #10 dimple die.

Let’s countersink the counterweight as a female dimple die.

Looks good.

Uh oh. I went a little far with my makeshift die. I stared at this for approximately 0.0000001 seconds before realizing I had to scrap the part.

See the ginormous cracks? Yeah. Not good.

A closeup of the other one. Oops.

So, the reordered part count is up to 2.

I’m not worried, I have some other stuff I can be doing while I wait for a replacement counterbalance skin (E-713, $8.85) from Van’s. Also, I immediately put in my order with Avery for a #10 dimple die (along with some clecos, an edge roller tool, and some more drill bits).

USE THE RIGHT TOOL FOR THE JOB, ANDREW!

Prev | Next

Leave a Comment » | Empennage | Tagged: #28, #6 dimple die, blue vinyl, clecoed, counterbalance skin, Deburring, Dimpling, end ribs, left elevator spar, primed, scuffing, skeleton | Permalink
Posted by Andrew

Prepped and Primed Left Elevator Skin

July 11, 2010

Prev | Next

Well, after an exiting morning with the South Carolina Breakfast Club, I was fraught with motivation. (I don’t know if I am using “fraught” correctly…)

Next thing on my long laundry list of things to do on the left elevator is to prep the skin for riveting to the skeleton. First thing, I got out the soldering iron and pulled off some more of the blue vinyl. While I was at it, I pulled off the blue painter’s tape I had been using to protect the back-riveted stiffener rivet lines.

All that shiny aluminum really makes me happy.

Then, on to deburring. I deburred both exterior sides of the skins, and then moved on to deburring the interior of the skins. I follow very closely with my maroon scotchbrite pad to help me remember where I have deburred (you can easily tell the difference between a deburred hole and one that has yet to be deburred…I am more using the scotchbrite pad as an excuse to give my fingers a rest…it is hard spinning that drill bit over and over and over).

The background holes are #40 (3/32") and the foreground holes are #30 (1/8"). I drilled these holes to #30 now because I don't want to wait until after the skin bending (at which point I won't be able to deburr them). Also, having the holes to final size will help with the annoying pop rivets that go in them.

Next up, dimpling the skin-to-skeleton holes. I scuff the interior of the skins before dimpling, because it is easier to scuff without dimples getting in the way.

I use my masking tape trick on the male dimple die, and I get ZERO circles around the dimples. So nice.

All holes dimpled.

Time to move on to edge-finishing. This little 90° corner is a tough one, but I think this ended up nice.

Edge-finishing.

After edge-finishing, I cleaned up, wiped everything down with MEK, and primed. Fast forward 30 minutes later, and now I get to pull the vinyl out of the skins (I’m trying to remind myself constantly to not forget the RTV in the trailing edge of the elevator bend before riveting.)

I probably add some time to the project by masking all of this stuff off and priming just the contacting surfaces, but I think it looks great (no one will ever see it) and I think I'm saving weight. Maybe not, but I sleep better because I do this.

It looks so good. I love this part of a subassembly, I'm getting close to riveting!

Last, but not least for the day was to prep and prime the two outboard ribs. These fit back to back and support the counterbalance and counterbalance skin.

On the priming table after getting a light coat of self-etching primer.

3.5 hours today on the project, but I’m only logging 3.0 here. See here for the other 30 minutes.

Prev | Next

Leave a Comment » | Empennage | Tagged: dimples, left elevator, MEK, Riveting, RTV, scuff, self-etching primer, skeleton, skin, soldering iron, stiffener rivet lines | Permalink
Posted by Andrew

Started Riveting Left Elevator Skeleton

July 5, 2010

Prev | Next

After the last couple work sessions priming various parts, I was getting all hot and bothered to rivet something. I thought I would tackle the spar reinforcements. I also forgot to charge the camera battery, so I’m using the new phone. Hopefully they turn out okay.

Here's the left elevator spar and reinforcement plates.

I got out a few rivets. AN470AD4-5 and -6.

Let's get riveting.

I clecoed the reinforcement plates and nutplates onto the spar, and riveted the four corners and one ear of the nutplate, then took out the clecos and riveted the rest.

The tape is a trick I have been using out of vanity. The rivets look better when they haven't been marred up by the rivet set.

After doing both plates, I put the spar back on the table.

Pretty.

And just to show you AGAIN how much I love my new tungsten bucking bar, here are the perfect shop heads.

The inboard shop heads.

The outboard shop heads.

Next up is to continue riveting on the skeleton, so I pulled E-705 out of the “recently match-drilled” pile and got it deburred, dimpled, edge-finished, and prepped for priming.

Ready to prime.

This is the other side after being shot with primer.

16 rivets set in 30 minutes of building after 30 minutes of shop cleanup (cleaned out the shopvac, etc).

Prev | Next

Leave a Comment » | Empennage | Tagged: clecoed, deburred, dimpled, edge finished, left elevator, Nutplates, Priming, Rivet, shop heads, skeleton, spar reinforcement plates, spar reinforcements, Tungsten | Permalink
Posted by Andrew

Started working on the Elevator Tab

June 20, 2010

Prev | Next

After some more days of not doing anything, I managed to make it out to the Pilots N Paws fly-in today. It was good motivation for working on the airplane.

Anyway, I’ve drilled the left elevator skin to the skeleton, and the next step is really to take everything apart, deburr, dimple, countersink, prep, prime and assemble…

BUT…

I have some things that need to be done first. Mostly, the directions want you to bend the elevator tab “ears.” Well, I don’t think I want to go the bent route. Here’s what I am worried about. I don’t think anyone would really notice, but I don’t love the way this looks.

Bent trim tab ears. I think I'm going to cut mine off and make little ribs.

I think with some work, I could make them look like this, but given how finished these surfaces are, I don’t know if they started as bent ears or riblets.

WHOA! This is awesome. This guy really finished this joint up nicely. Everybody be jealous.

Finally, I found a really nice riblets version. I like this, and this is what I am going to be aiming for (although I am going to try to use solid rivets.

Great finish on the cut-instead-of-bend tab ears. I'm going to strive to make mine like this.

Anyway, I also think cutting the ears off (not bent down in the way) will allow me to use solid rivets in the blind-rivet locations on the top and bottom of the elevator (outboard trim spar rivets). We’ll see.

First step is to get the skeleton re-clecoed in the skin.

The trim spar and the inboard rib.

Van’s wants you to countersink either piece for flush rivets (not for any real flush reason…I think they need to be #40 size holes, and they don’t give you any universal head AN470AD3 rivets). Anyway, per standard practice, I dimpled both.

Dimpled instead of countersunk.

After clecoing together the skin, I am ready to start the headscratching with the tab. Let’s find the tab spar.

There it is.

Let’s go ahead and cut off these tabs. After careful measuring and marking, I’m ready to put blade to metal.

Inboard side. I'm nervous about chopping these off.

Outboard. (see how I lined up the line parallel to the flat portion near the top and to the left of the relief hole near the bottom? This doesn't work. Read on to find out why.

After a quick snip (not too close to my final line) I removed the vinyl from the interior of the skin in preparation for using a file and scotchbrite pad to clean everything up.

Devinling before finishing those cuts.

After working carefully with a file and edge finisher…

Looks good.

Before I really finalize things, I’d like to get my tab placement set up. First, I tried using this extra piece of rudder stiffener.

It worked okay, but I later switched to something a little longer.

After some moving around and fiddling, I re-read the directions, which tell you to bend the elevator ears down along a bend line that is perpendicular to the hinge line. Well, that means that the cut lines should be perpendicular, too. Of course, like I mentioned before, my original outboard line wasn’t perpendicular. All that file work for nothing.

I drew new lines (one on top of the other, ignoring the needed clearance).

Drawing new, perpendicular lines.

Then, I made a “pretty close” cut with the snips. I’ll need to really clean this up, as well as move the line to the left for clearance purposes (I’ll wait until the hinges are drilled to really see what I need. (The instructions call for 3/32″, but that is for the blind rivet head clearance that I won’t have to worry about.)

Pretty close, but still needs trimming and finishing.

Next, I moved back to the tab. Here’s my new line.

I'm bummed because the upper part of the tab, factory provided, is not perpendicular to the hinge line. That means there will be a slight angle there. Bummer.

After getting those refinished, I got the tab mocked up. I kind of worked backward. I want to use the inboard edge and the trailing edge to get placement, then verify I have adequate clearance on the outboard edge and between the tab and elevator for the hinge (there are some hinge dimensions on the plans). I think I’ll have plenty of room.

This looks good, but I'll have to keep trimming that outboard edge.

Here's a closeup. You can see the edge near the top of the tab is angled a little left. This is how it comes from the factory. The marker line and aft portion of the tab are both perfectly perpendicular to the hinge line (line through the center of the rivet holes).

Later this week, I’ll work on getting this perfect, then tackling the riblets that need to be constructed before doing any more work with finishing the skin.

Prev | Next

Leave a Comment » | Empennage | Tagged: assemble, bend elevator tab "ears", countersink, Deburr, Devinling, dimple, Drilled, fly-in, left elevator, Pilots N Paws, prep, prime, Ribs, skeleton, skin, solid rivets | Permalink
Posted by Andrew

Drilled E-701 (Left Elevator Skin) to Skeleton

June 17, 2010

Prev | Next

Wow, it’s been a week since I’ve worked on the airplane.

I have an excuse, though. I’ve been installing wood floors. Here’s the living room, almost done.

Anyway, if you remember from the last post, I had the left elevator skin clecoed to the skeleton. I went ahead and match-drilled the skin to the skeleton. Instead of using my cordless drill (because it’s quieter), I broke out the air drill and went to town. I love the way that thing sounds.

Forgot to charge the camera battery, so it charged while I drilled.

After matchdrilling both sides, this picture is me in the middle of removing all of the clecos.

Then, because I felt like I would be short-changing you if I didn’t have two pictures for you, here’s another one.

After disassembly.

Here’s the catch, though. I have a lot of thinking and pondering to do about some things.

First of all, I am planning on cutting off the elevator tab (and elevator) bent ears and just making a rib out of them. Jason Beaver did it pretty successfully here and here, so I’m basically going to copy him.

The question is whether to prep and rivet the left elevator now, the cut off the “ears” after riveting, then try to fabricate a rib, matchdrill, dimple, prep again, etc., or should I re-cleco everything together and do all of that fabrication now.

Many people use blind rivets for the extra tab fabrication, but I think I am going to try to use solid rivets. I have had some success in the past with solid rivets in tight spaces using a special bucking bar (namely, the end of a BFS (“big-freakin-screwdriver”). The question will be about dimpling.

Also, I can probably cut the ears off, but leave a little extra material. I need to make sure I line up the cuts on the elevator and tab to minimize the gab between the two, and I don’t want to cut to much off of either side. Maybe I’ll mock them up, cut one side to where I think it should be, and make sure the other side can be cut more precisely to match the first cut.

Also, many people use blind rivets for the four trim spar rivets on both sides (per the plans), but I think I can assemble in an order that allows me to use solid rivets, especially since I’m going to cut the elevator bent tab ears off; I should be able to reach in there with a bucking bar.

See how much thinking I have to do?

Prev | Next

Leave a Comment » | Empennage | Tagged: BFS ("big-freakin-screwdriver"), clecoed, Clecos, cordless, dimple, drill, fabrication, floors, left elevator, match-drilled, matchdrilling, Rib, skeleton, skin, wood | Permalink
Posted by Andrew

Backriveted Left Elevator Stiffeners

June 1, 2010

Prev | Next

I wasn’t feeling well today (sore throat, could harldy swallow), but after a nice long sleep-in and a nap in the afternoon, I went out to the garage partly because I wanted to sweat out some of the demons. I didn’t take a ton of pictures, but I managed a few.

I broke out the c-frame and dimpled the skins.

First up, skin dimpling.

I did much better on the trailing edge dimples than last time (see this post).

This is the worst one, but it still looks great, and is hardly noticeable unless you are really looking for it.

After dimpling, I wiped down all of the scuffed areas with MEK to rid them of fingerprints (oils) aluminum dust, moisture, etc., and then primed.

Primed interior. Notice how I leave a lot of the blue vinyl on the skins? This helps keep weight down (although undoubtedly adds to build time while I painstakingly trace around the stiffeners with a marker and use those lines to devinyl.

Moving back to the skeleton, I mounted a one-leg 1/4″ nutplate in the forward tooling hole of the counterbalance and tip ribs. This will hold any future weight I need to balance the elevator with paint.

I used an undersized countersunk screw in the tooling hole to help locate the nutplate, then drilled one hole and clecoed from the back.

Both holes drilled, and the main hole enlarged to something a little larger than 1/4"...I can't remember...maybe 5/32"?

Next, I moved back to the spar. I have read where a few people have added a hole in the lightening hole area of the elevator control horn/spar area. The right hole is for manual trim or for the (what I’ll call “retracted”) jack screw and wiring runs for the electric trim motor. I, like others, don’t like the idea of the wires and jack screw sharing the same hole, so I drilled another hole, in which I will add a 3/8″ snap bushing.

Pilot hole eye-balled.

Crap, I didn't even get a picture of the final size hole. (I drilled it to 3/8".)

After completed the extra hole, I noticed the skin was dry. Nothing to stop me from backriveting, now.

Rivets place in, and taped to, the first stiffener row.

Same thing with the trim reinforcement area.

After backriveting the trim reinforcement. Man, this makes me happy.

The next couple rows, done.

The bottom half went smoothly. The top half now has rivets taped in place.

Where are those stiffeners?

This isn't a very exciting picture, but they are all riveted.

Here's the inside.

I love this picture. This is the trim reinforcement plate area.

So nice. (That scratch at the top is very superficial. It'll buff right out, I promise.)

Biggest lesson today was about the aft-most rivet in the stiffeners. When bending the skin out of the way to reach that rivet, everything twists out of alignment. If you start with that rivet, it is easier to make sure everything is flush than if you rivet the forward ones first. Start from the back and move forward. You will get better results.

Prev | Next

Leave a Comment » | Empennage | Tagged: C-frame, clecoed, counterbalance, dimpled, interior, MEK, Nutplate, skeleton, skins, Stiffeners | Permalink
Posted by Andrew

Started Left Elevator

May 24, 2010

Prev | Next

Well, it’s monday. And even though I have a couple things remaining on the right elevator, I am going to follow the flow of the directions and move on to the left elevator before coming back to finish both of them.

In addition to the items they want you to do to both at the same time (roll leading edges, install rod-end bearings, etc.), I’ll have to come back to do three things on the right elevator:

Fix a few over-driven rivets (and a couple that bent over that I didn’t catch at the time.)
Figure out how to add RTV to the trailing edges after the fact (anyone have any ideas?)
Trim down the counterbalance. I elected not to do this on purpose.

Anyway, on to the left elevator. Here’s the obligatory changing-of-the-plans shot.