Started Preparing the Right Wing Lower Skins

August 5, 2012

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Well, after a busy morning at the SCBC, I did get an hour in on the lower right inboard skin. I’ve decided to go ahead and close up the right wing before proceeding. A lot of people wait until much later in the project (which the instructions say you CAN do if you want), but everyone who waits says there is no real benefit to waiting, so I’m going to go ahead and get them closed up now.

First, I pulled the skin off the wing, and then got to work. I spent about 30 minutes edge finishing, then another 30 dimpling about half the skin with the c-frame. (No, I didn’t forget to drill or deburr, I had done those previously.

This picture is from after edge finishing, but before dimpling.

After I finish dimpling, I’ll prime the inside surface. Then, I’ll deburr and dimple the wing ribs, and rear spar, but I’ll need to remember to countersink the flap brace.

1.0 hour.

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Dimpled Right Upper Wing Skins

July 31, 2011

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Holy crap I got a lot done today. If you remember from yesterday, I forgot to attach a wire for the float fuel sender. Instead of ordering an appropriate sized wire, I used some of the only aircraft grade wire I had laying around, which was some 16 AWG. I know that is way too big (we’re just measuring a resistance), but it’ll work so I can install these tanks for the last time today.

Some people run two wires, but I checked the resistance through the tank, and I’m getting a nice solid reading from the tank itself, so here’s my one wire to the center conductor.

First official aircraft wiring. Done.

After reinstalling the tank, I held the wire to the negative lead and held the positive lead against a few different points on the tank.

All read between 38Ω and 240Ω or so, so I’m good.

Sweet. I don't have to unseal the tank to attach another wire to the sender body.

I’m flying through these skins right now. Pretty soon, I’ll have nothing left to do other than install the upper wing skins.

On tap for today is some dimpling and priming.

Here’s the inboard skin, ready for dimpling.

...on the nice vacuumed workbench.

Oh yeah, don’t forget your scarf joint. (A nice transition from the inboard skin to the outboard skin by the tank so there isn’t a big step.)

Looks good from this angle.

I also filed down the inboard side of the outer skin (the one I’m holding below).

Okay, this looks like it will work.

For some reason, you can see a little of the edge on the left side of the picture, but I didn’t notice this with my naked eye.

I’m very happy with it. It is a great transition from tank to skin.

I'm very happy with this.

After the scarf joint, I spent about 2.5 hours dimpling.

I've been using the male die on top with great success.

More dimpling.

After a little prep, I shot these with self-etching primer.

I sprayed them outside, then moved it back inside to dry.

For the outboard skin, I actually hung it inside-out on the wing.

More priming glory.

The wingwalk reinforcement skin.

And finally, the exterior side of the inboard skin where it will underlap the outboard skin.

3.0 hours of dimpling fun. All I have to do now is deburr and dimple the skeleton. Then, skin riveting!

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Dimpled Right Tank Skin

June 4, 2011

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Well, Andrew went shopping today!

It’s been brutal in the shop, so I put up the electric heater I had on the bench and put in its place this new VORNADO. For such a small package, it does a pretty good job of moving air. You have to have it pointed right at yourself though.

The VORNADO. (insert ominous music here)

Also, I bought the craftsman circle cutter for the large 6″ holes I need in the fuel tank inboard ribs.

Time to cheat death.

i also picked up some 1/4″ and 3/8″ drive drill adapters. I hate having to use a ratchet all the time for bolts. Now I can use the drill.

Oh, and a 7/16″ drill bit for the inboard rib vent fitting holes. The -4 sized AN hardware requires a 7/16″ hole.

This stupid drill bit was $14. Jeesh.

Also, I bought a nice little kitchen scale. I thought about saving some bucks and going with the analog one, but I didn’t know if I would be happy not having the digital readout.

This one was about $30.

These pliers weigh 155 grams.

Okay, back to work, Andrew!

I broke out the c-frame again and loaded in my tank dimple dies. On all of the other skins, I’d been putting the male die on the bottom, putting the hole in the skin over the die, lowering the female die, and then holding it in place while I struck it with the hammer.

On these skins, I’m flipping the skin over (so the other half of the skin hangs off the front of the workbench toward the ground).

This means I have to have the female die on the bottom, and the male die on top. To avoid my figure-8 dimple from the leading edge, I removed the return spring from the c-frame so any fidgety hands won’t cause anything to move.

Here I am about halfway through with the bottom half of the right tank skin.

(Whiny voice:) My hand got really tired (the hammer is sooo heavy, sissy boy!), so I took a break.

Not sure why I weighed a cleco, but I was curious.

13 g. Hmm.

Back to work again. Here’s the bottom half of the right tank skin.

Since there are more holes on the bottom than on the top, I am more than halfway done!

A closeup of the top skin dimpled.

The hole (get it?) thing dimpled.

At this point, I had been working for 1 hour and 20 minutes, so I felt like I should find something to do for 10 minutes just so I can log 1.5 in the build log. I broke out the #8 dimple dies and dimpled the #19 holes in the outboard edge of the tank skin.

You can see the size difference between the #40 and #8 dimples (The numbered comparison is not right here. #8 screws require #19 holes, so you are comparing #40 to #19).

With a few minutes left, and a new tool just itching to be used, I broke out the 7/16″ drill bit and drilled the vent fitting hole in the inboard rib.

I’ve been following a few threads on VAF recently, and some people are really freaking about about an exact location for this. I followed Van’s directions explicitly, which say “approximate location.”

Ha. I didn’t even give myself a starting mark!

Looks good.

Then, I pulled out the -4 fittings and screwed them in, just to see what they would look like.

The plans show this pointed foward. Okay.

The VORNADO!!!!!!!!!!!!!

1.5 hours. Proseal arrives on Monday. Next week is the black death!

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Bent Left Elevator Trailing Edge

June 2, 2010

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Sick again today, but I did get a little work done.

First, I spent a considerable amount of time looking at the 4 horizonal holes below. The plans show them as blind rivets, but there has to be a way to get solid rivets in there.

After much deliberation, I think if I drill them to #40 now (gasp, without matchrilling!?) Then I can deburr, scuff, and dimple the area now. I’ll do the same to the equivalent holes in the trim spar, and then attach (at a minimum) the top skin to trim spar holes with solid rivets. I think I will be able to get both sides, as I am planning on cutting off the “bent tabs” from both the elevator and trim tab.

First, drill to #40.

Then, deburr interior and exterior, and scuff the interior only.

I got the c-frame out again and dimpled the holes.

I should be able to make that work out for me, but more on the bent tab cutting later on.

Next up is bending the trailing edge. After inserting and taping a 1/8" dowel in the trailing edge, I bent it in my bending brake. This picture is about halfway bent.

Then, I removed the dowel, bent it the rest of the way, and did the same with the trim tab since I was in the bending mood. (Side note, the trailing edge on the elevator looked great, but was not constant radius…it was larger radius toward the tip. I grabbed the hand seamers and gently squeezed the areas so they were all the nice crisp radius that the inboard trailing edge was.)

Trim tab bent.

Also, I way overbent the trim tab. There are no stiffeners in there to stop you, so you can basically flatten the thing, even with the dowel rod in there. I opened it back up a little by hand, but it’s not perfect. If I can’t get it back to perfect, I’m going to order another one. I think I can work with this one, though.

This is a radius shot of both the elevator only.

Here's one with the tab held in place. Looks good to me.

Another sickly hour today. Can’t complain.

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Backriveted Left Elevator Stiffeners

June 1, 2010

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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.

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Primed the rest of the Left Elevator Stiffeners

May 31, 2010

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Tonight, I moved on with the left elevator by matchdrilling the upper stiffeners.

Here are the upper left elevator stiffeners, after trimming, being matchdrilled to the skin. First, I drilled and clecoed the forwardmost hole.

The three forwardmost holes clecoed.

After finishing, I traced the stiffener outlines on the inside and outside of the skin.

These will help me devinyl later.

You can see I have already done the lower surface of the elevator (it's upside-down on the table).

And, of course, since I forgot to add RTV to the right elevator (still trying to figure out a way to get some RTV in there), I wrote a little reminder on the inside of the left elevator.

Hopefully I'll see this as I pull out the last of the blue vinyl just before assembly.

Next, devinyl along the traced lines and then deburr and scuff.

Left elevator skin interior after devinyling, deburring, and scuffing.

Next up, I deburred and scuffed the remaining stiffeners. (I don’t have any pictures, but after this, they got dimpled and then primed.)

Because the upper surface doesn't have the trim reinforcement plate, there are 4 (instead of 3) of the short stiffeners.

Next up, devinyl and deburr the outside of the skin.

Skin devinyling.

A small tip here. I decided that at the aft end of the elevator, i would leave a little blue vinyl instead of connecting the upper and lower surface bare spots. This way, If I need to rest the elevator on its trailing edge, I won't be damaging the finish on the trailing edge.

Because it was late, I couldn’t use the c-frame.

Instead, I grabbed the hand squeezers and dimpled anything I could reach.

Just for kicks, I held up the trim reinforcement plate (and cover, still covered in blue vinyl) which will be riveted underneath the skin to the right.

Here are the other sides of the upper stiffeners getting primed.

I toook these inside for a good washing with Dawn before drying them, wiping with MEK, drying some more, and then shooting with primer.

I had a few more minutes, so I started match-drilling the skeleton. Here is one of the spar reinforcement plates being drilled to the spar.

I used my 12" #30 bit due to cleco-clearance issues.

Finally, before heading in, I shot a coat of primer on the other side of the upper left elevator stiffeners.


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Fixed Right Elevator Trailing Edge

April 24, 2010

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I’ve been lacking in motivation recently due to some badly dimpled holes along the trailing edge of the right elevator. All last week, my error had been hanging over my head, and I was having trouble even motivating myself to fix them.

Saturday afternoon (writing this later) I mustered up some courage and drilled out 13 of the 14 trailing edge rivets on the right elevator. They are really not trailing edge rivets, but the aft-most rivets of each of the 14 stiffeners (7 on the upper skin, and 7 on the lower skin).

You can't even really see the damage in this picture...

Here’s a couple pictures of the damage.

You can see how the dimple kind of tweaked the skin. Boo damaged skin.

The above pictures was the worst one. This one was more typical.

A small ridge below the hole (in the picture) and a small dent above the hole (in the picture).

After getting them all drilled out (13 of them, one of them was good enough to leave alone), I set up the skin with a long backriveting plate underneath the offending holes and used a 2×4 laid spanwise on the stiffeners with some clamps to keep the skin surface flat. Then, I used 4 or 5 long pieces of tape to pull the upper skin back to allow plenty of room to work.

You can still see where the very trailing edge is starting to bend down. This is why I had the problem in the first place.

With no rivets in the holes, I used a small flush set (about 3/8″ diameter) and my rivet gun turned way down to flatten the dents (I’ll call them dents for dramatic purposes, but they were really just small impressions) and ridges (again, really just small high spots) flat. I put the flush set on either side of the existing dimple (which was okay, it was the area just outside of the dimple, where the edges of the dimple die set had tweaked the skin a little, where I was having my problem) and gave it a few taps.

After finishing one side, I took off the protective tape I was using and inspected. It ended up okay. I think if I were going to polish the empennage, it would bug me, but my latest paint scheme idea has me painting the elevators.

I did the other side, and then cleaned everything up, put some rivets back in the holes, and set up each side again with my fancy setup to actually backrivet the last hole of the stiffeners in place. It went perfectly, and I was really careful to hold everything very flat against the backriveting plate.

(By “perfectly,” I really mean “I messed up one of the holes, had to drill it out to #30 and use an oops rivet.” ) I’ll point it out.

Here are some examples of the replaced finished rivets.

This one looks great!

Pretty good. You can still kind of see where the damage was.

Holy crap, how did I do that to the rivet? This is the one that got drilled out again and replaced.

Here's the shop head for the oops rivet. This was my first real oops rivet. Not bad.

This one is okay.

Another very nice one.

It's not blurry in real life, I promise.

Whoa, who scratched my skin? It was probably the male part of the dimple die. That will hopefully polish out, (or it will get cleaned up and painted).

Another good one. In all of these, you can kind of see the larger diameter area that was dimpled.

This one is on the very end, as you can see the devinyling lines.

It looks the same as all the rest, of course, so you’ll never know, and I’ve already forgotten which side (top or bottom) it’s on.

Anyway, I drilled out 13 of the 14 original rivets, then had to redo one of those, so 14 rivets drilled out and reset successfully in an hour today. Not bad. I’ll add pictures when I can get them uploaded. Sorry for the lack of work recently.

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Skin Dimpling and Priming

February 22, 2010

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I snuck home over lunch today to get a couple things done, one of which was work on the airplane loudly. First, I set up my c-frame and spent some time verifying, re-verifying, and trip verifying that I was going to dimple in the correct direction. These rudder skins are thin, and I didn’t want to make any mistakes here. I set the skins on the table with the exterior side up, and the c-frame with the male die above, pointing down, and then dimpled all the holes in the skin. Jack and Ginger (who were inside), clearly don’t like me dimpling with the c-frame and told me so with a pair of barks, each. We did get into a nice rhythm, though. [whack]  Bark, bark…bark, bark.  [whack] Bark, bark…bark, bark. It helped pass the time, but I hope I didn’t cause them too much stress.

My dimpling setup for the rudder skins.

After that, I flipped them over and cleaned the scuffed lines.

Skins cleaned and drying.

After drying, I shot them with some self-etching primer. I was at the end of one of the cans, and some of the stuff came out kind of splotchy, but I think it will look good after it dries. I can always lay down another coat.

The left skin after priming.

Another thing. I’ve been putting blue tape on the exterior side, then laying the skins down flat and shooting them with primer. When I do this, some primer gets into the dimple (from the underside I am priming), and kind of bounces off the sticky side of the blue tape and settles in the dimple on the finish side. Today, I made sure none of the holes were obscured; hopefully that will prevent any primer from getting on the exterior surface. I thought about taping the final rivets in the dimples, since that is the next step with the skins anyway, but I am not sure about using self-etching primer on unset rivets, then setting them. I have never seen that done before, and I don’t want to be the first guy to try. I’m sure I would have been okay, but the other way seemed to work fine.

And the right skin after priming.

After work, I put rivets in all of the dimples, taped them up, and flipped the skins over to lay the stiffeners in. One note, since I am using the tank dies, the rivet sizes must be lengthened in some places. All of the stiffener rivets were too short before setting, so I am going to substitute AN426AD3-3.5 rivets for the AN426AD3-3s called out in the plans. Except for the aft-most rivet in each row. The construction manual tells you to make sure you set this rivet fully, so I’m going to leave the shorter one in there.

See these rivets? They look okay, until you put the stiffener in

Once you get the stiffener in, you can see they aren’t the recommended 1.5 times diameter. I’m also a little concerned that the dimpled holes are a little big for the rivets. I didn’t notice this on the other components using the tank dies. Hmm. I’m going to look around and see if anyone else has encountered this.

Not long enough. (TWSS)

I was moving along merrily until I got to this hole. Doh!

Forgot to dimple this hole. I had to break out the c-frame just for this one lonely hole.

After I got all the rivets in and taped, I flipped the skin over.

These rivets will be long enough.

Then, one by one, I final trimmed the stiffeners (snipped the 90° corners off with the snips) and laid them in to see what it would look like.


A solid hour and a half. After edge prepping and priming the stiffeners, I should be ready to install the stiffeners permanently.

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Skin Dimpling, Edge Finishing, Priming, Riveting

January 30, 2010

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I worked in sections today.

There was a big storm here last night, (and all of today), but I’ve learned that cleaning off the driveway is a lot easier if you do it when it is 3″ two times instead of once after 6″ has accumulated. Here’s what I woke up to this morning.


Here’s after about an hour of shoveling. Good workout.

Coming down fast, but at least I cleared off the first 6".

Then, I got the c-frame out and finished the VS skin dimpling. I replaced the blue tape on the male die, and got almost no circles.

Simple but effective dimpling setup.

Then I countersunk all of the lower forward spar reinforcement holes from the plans. I haven’t used the countersink since I had to countersink HS-710 and HS-714 to accept a #30 dimple, so the countersink cage was already set up. All I had to do was verify in a piece of scrap. Yup. It’s perfect.

Beautiful countersinking.

Then, I cleaned and primed one interior side of the vertical skin, then the other. Here’s the first side drying.

Hurry up and wait to dry.

After finishing the second side and letting it dry, I pulled the forward section of vinyl off of the interior side of the skin. During assembly, no bucking bars will be needed in there, so there is no risk of scratching. Then I finished edge finishing the ribs, spars, and rear spar reinforcement, and primed each one. I didn’t prime them sitting perfectly horizontal, so I got some runs and some nastiness; some of them ended up getting touched up, and some got a second coat.  After they were all dry, I cleco those bad boys together in preparation for riveting.

Skeleton and rear spar taking shape.

I started with the skeleton, middle rib. Here’s my first VS rivet.

First VS rivet.

Then, I moved to the tip. See the upper rivet? The skins are sitting flush, this will have to be drilled out.

Ahhh! I suck at riveting.

And the lower rivet there started to bend over. I’ll have to drill out both rivets.

Two rivets to be drilled out.

Back to the middle rib, two more perfect rivets.

There are pretty good. I need to make sure that bottom one is driven enough.

See the fourth rivet from the right? Started to bend over, so I’m going to drill it out. Also, I’m going to put the shop heads on the thicker material here, also, they’ll be easier to inspect.

Uh oh. See the third rivet from the right? I was supposed to wait and rivet this with the skeleton. Slow down and follow the directions!

Two more rivets to be drilled out.

But I was feeling good about squeezing, so I kept going. Until these 4 rivets. Terrible…they all started to bend over. I think my rivet squeezer sucks. I have to squeeze really hard and it it tough to keep everything aligned. I think after I drill these out I am going to shoot and buck these.

4 bad rivets to be drilled out.

At this point, I had to walk away, I was tired, frustrated, and not making any progress. Ugh.

So far, 3.5 hours. I set some rivets today, but I’m not going to count any of them until I drill them out. I’ll update the rivet count later.

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VS skin Deburring and Dimpling

January 29, 2010

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Today, I didn’t make it outside until late, so I didn’t get a lot of work done. Here’s me starting on deburring the skin. Yes, I am using the Van’s recommended “spin a drill bit in your fingers” method. It works for me.

Action shot of me deburring.

An example of a deburred hole. The hole on the right is deburred. There is a very small chamfer on it from the oversized drill bit. It’s easier to see because it’s catching the light from above.

Deburred hole there on the right.

After deburring, I scuffed up the interior of the skin with a maroon scotchbrite pad.

Scuffed, ready to dimple.

Because it was so late, I didn’t want to break out the c-frame. I grabbed the hand squeezer and finished what I could reach.

These are regular (not "tank") dimples. No circles when you use the blue tape trick.

And here’s the vertical stabilizer skin, deburred and dimpled around the perimeter. When sound level permits, I’ll get the c-frame out and dimple the remaining holes.

Almost done with the skin.

I counted 104 holes per side for deburring. That’s 208 holes, 416 deburring operations needed. I usually spin the bit 4 times, which makes 1664 spins of the drill bit. Oww…

1.0 hour closer to being done.

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