Started riveting right HS

January 15, 2010

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I managed a couple hours in the shop today, even though I was as sick as a dog. In between frantically running to the bathroom to pray to the porcelain god, I did get a couple things done. I planned to get some of the right HS done today, which needed more prep on the skin, and then some riveting.

First, I cleaned and primed right HS skin interior.

Right HS skin all primed and such. Well, on one side, at least.

After flipping, priming the other side, and letting it dry, I decided to fix some of the bad rivets from the other day. They look better now.

HS-710/HS-712 to HS-702 rivets fixed.

Then, I grabbed the right HS ribs and front spar and clecoed some of them to the left HS. I

Right spar clecoed to the left HS assembly. This thing is getting big.

I started by riveting the front spar to HS-710 and HS-714. This time, I was following the directions a little more closely. All of the rivets today turned out great. I had switched from my offset cupped set to a straight set, and they were all perfect. (Don’t mind the two empty holes on the far left, I remembered them later and shot those rivets, too.)

Great rivets if I do say so myself.

Then I riveted HS-405 and HS-404 to front spar. Again, no mistakes. Then, I turned back to the skin once it was dry. On the left side, I waiting until riveting HS-707 and HS-706 to the skin before I devinyled this area. On this skin, I figured that I wouldn’t be holding a bucking bar (that I could drop and scratch the skin) in this area, so why not take the blue off before making it hard on myself. Much easier this way, but I could only do it here. (I have to admit, those nice straight primer lines make me happy.)

Back to the skin. Devinyling the easy way.

The directions have you cleco in HS-707, rivet to the bottom skin, then cleco in HS-706 and HS-708 (to help the skin take shape and sit tight against the aft holes of HS-707), and then rivet HS-707 to the top skin. Just like the left side, I needed AN426AD3-4 rivets where they sometimes call out an AN426AD3-3.5.

The, I let this happen.

Uh oh...

What? Don’t see anything? Try this angle.

AAAAAAAHHHHHHHHHHHHHH!

NO!!!!!!!!!!!!!!!!!

:-(

It was completely my fault. I was getting confident, and was holding the rivet gun with my left hand. I had the pressure set near 50psi (I usually use 40psi for the AD3- rivets) and the gun got away from me.

I stared at it for about 5 minutes, realizing that it was probably okay, but would essentially force me to bondo and paint the tail, which would not have been the end of the world, except I still might want to polish the airplane.

I decided to drill out the 4 rivets I had set in the bottom skin to see if I could help it any with a flush set from the back side. I managed to get my backrivet set in there a little, and it helped, but I came inside as I was getting chilled and frustrated.

Later, I realized that I have a c-frame, and with two flush sets in there, I may be able to very gently hammer it back into shape (or at least get it close). I’ll have to re-dimple, too, because I flattened out the dimple while trying to fix the dents.)

…so…mad…

Maybe this weekend I can fix it up a little and keep going.

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Posted by Andrew

Squeezed more left HS Rivets

January 11, 2010

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I got some rivets squeezed tonight, which means it was a good day. All of the rivets tonight were either HS-601PP (skin) to HS-706 (tip rib) or HS-601PP (skin) to HS-404/405 (inboard ribs). All squeezable.

The plans have you skip 5 rivets on the top only, but the clecos were doing such a good job of holding the skin off of the table, I decided to skip those rivets on the bottom, too. Also, I only squeezed every other rivet on the tip until I can get the rear spar riveted in. Then, I’ll finish the whole thing off.

On the top of the skin, Van's has you leave the rearmost HS-405 hole open, then every fourth rivet forward of that. Here are my first three squeezed AN426AD3- rivets on the project.

Then I got up to the HS-601PP (skin) to HS-702 (front spar) to HS-405 (aft inboard rib) hole. You can see that the longer rivet they call out (AN426AD3-4, instead of -3.5) isn’t long enough.

Bad picture, but the rivet at the top of the picture is not going to be long enough to form a good shop head.

So, I replaced it with an AN426AD3-4.5.

An unsqueezed AN426AD3-4.5. That looks like it will be long enough. It was.

Then, I spent a few minutes looking over my work from yesterday. It generally looks pretty good, but I must have been distracted during these three or four rivets (at least they are on the bottom of the skin). Not a big deal, but when you look at it in the right light, you can see some small dings.

A couple small smilies and dings. These make me want a swivel flush set. Hmm. It looks like I didn't keep the rivet gun straight. Bummer.

From today, two of the rivets I squeezed didn’t sit correctly in the dimple. They are probably just fine, but I’m going to replace them. (I know, I know, they will be under the empennage fairing, but still, I want them better than they are.)

Only two rivets to replace tomorrow. Better than yesterday's average.

30 quiet minutes today, after the girlfriend and puppies went to bed. I’m so sneaky.

38 rivets tonight, 2 I’ll have to drill out tomorrow, but don’t count against my batting average tonight.

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Left HS Riveting

January 10, 2010

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Today I started left HS skin riveting.

The big takeaway is that I hate squeezing AN470AD4- rivets. For some reason (it’s gotta be user error), I keep bending them over. Finally, I broke out the gun and got some rivets set. I think I may need a better bucking bar. The fact I set some really nice rivets with the crappy bar means that a tungsten bucking bar will probably be my favorite tool.  Anyway, first picture is me riveting HS-710 and HS-714 to the left HS-702 front spar. You can see the two rivets in the upper right side of the picture needed to be drilled out. Oh wait. They all needed to be drilled out. See how I put the manufactured side on the thicker material here? Wrong, drill them out. That’s one of the reasons I drilled out 11 rivets today. I didn’t get all of these reset, but I did get the ones that would be inaccessible once I started riveting on the skin. In the picture below, I set the six behind the HS-404 rib, and six of the ten in front (lower right) of the HS-404 rib. A few of those bent over again, so I called it quits on this part and moved on. I’ll have to drill out more rivets tomorrow. Ugh.

Squeezed, and then drilled out HS-710 and HS-714.

Next, I started some skin riveting, with the HS-707. You can see my first two skin riveting shop heads.

My first two flush rivets (well, first two on the skin).

Then I shot two more and took this picture. Sorry about the fingerprint smudges. Rest assured, the skin is nice and smooth.

First 4 flush rivets on the left HS. They look so good.

Finished up the top, and then riveted the bottom (except for the last bottom skin rivet, the bottom 1/8″ cleco prevented the bucking bar from getting in there, so I’ll set this after I remove HS-708). The second and third rivets on the bottom need to be replaced. They are probably okay for such a non-structural area, but I am a perfectionist.

After riveting the top and bottom skins (to HS-707). Except the most aft skin rivet on HS-707. (See the lower 2nd and 3rd rivet from the right? Those shop heads are too small. I'll need to replace those.)

Drilled them out, and replaced them. They look much better now.

Replaced with AD3-4 instead of AD3-3.5. I don't know why these needed longer rivets when every other rivet looked okay.

Next, I finished riveting HS-710 and HS-714 (front spar reinforcement angles) to HS-702 (front spar). Shop heads on the thicker material.

HS-710 and HS-714 successfully riveted to the front spar.

Here’s a closeup of the two replaced rivets.

Another closeup of the HS-707 rivets.

Next, they have you cleco in the front spar and cleco HS-708 (what I am calling the middle aft rib) into place. (Ha, the Yard gave me a long reach 3/32″ cleco in my bag of used clecos. You can see it on the upper left.)

Clecoed the front spar and HS-708 in place, ready to blind rivet.

One of the LP4-3 blind rivets set. I had to grind down my cheapo National Tool and Equipment blind rivet puller. Not hard, took about 5 minutes, and ended up working really nicely in here.

First blind rivet on the project. (I think it's an LP4-3.)

And all three complete.

All three blind riveted. Time to move on.

Here, I got a shot of my painter’s tape covered bucking bar just after bucking the lower tip rib rivet.

Riveting HS-706 (tip rib) to HS-702 (front spar). I think I could have squeezed these if I had unclecoed the skin a little, but I was feeling good about shooting them, and I'm not a fan of squeezing AD4- rivets since the "let's have fun squeezing and drilling out 9 rivets" fiasco this morning.

I like these rivets. They gave me no problems.

Done!

Next, I started setting the skin to front spar rivets. I shoudl elaborate on my technique a little here. I would remove a cleco, put in the AN426AD3-3.5 rivet, put some blue painters tape over the rivet, then shoot and buck it. The tape did wonders to protect the skin from any blemishes caused by the flush rivet set. I taught myself this trick after scratching the hell out of the practice kit. (note: I wish the practice kit had more AD4- rivets in it.) Anyway, these all look sufficient…

The first skin to spar rivets on the top.

I managed the rest of the HS702 (front spar) and HS-708 (aft middle rib) to skin rivets. There were 42 of them. On each side. I wrapped my bucking bar in blue painters tape to protect the skeleton from dings and scratches. Worked like a charm. I’ll replace all of the tape then next time I have a big rivet day.

I wrapped my bucking bar in tape. Here is the result after 113 rivets today. (Well, 124, I had to drill out 11 rivets.)

Here are some after shots. The HS is upside down, so even though this is the left HS, we are looking at the tip rib here.

All done. I may go back and see if there are any underdriven rivets in here. I was being rushed back into the house for dinner after I finished riveting.

Looking at HS-708 and the blind rivets holding it to HS-702 (front spar) and HS-707 (middle tip rib). It looks like the spar is scratched here, but it is really just a couple scuffs from my knuckles and the handle from the blind rivet puller.

More after pictures.

This is looking toward the center of the airplane (toward HS-405, aft inboard rib)

And again.

No closeups, because I didn’t clean off the skin yet, but still, it looks so nice. Also, I need to remember to stop dripping air tool oil all over my workbench.

Hooray for a riveted skin. It looks like it might fly one day.

After I got all the riveting done, I started peeling off the blue vinyl from the interior. The primer on the vinyl flaked off as I peeled, and it got everywhere. I don’t know how to prevent this, though, and after a quick sweep with the vacuum, it looked wonderful again. Before I close up, I’ll probably wipe off the unprimed aluminum with acetone or similar to make sure I have all the fingerprints (oils) off.

Removed the blue vinyl on the interior. Me likey.

I also got a half hour of right HS skin deburring tonight. We’ll see.

Noon to 1pm, 1:30pm to 4:30pm, then 9-9:3pm while watching the UNC/VT game. Go heels. 4.5 very productive hours.

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Posted by Andrew

Rear Spar, Front Spar

December 30, 2009

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Well, I finally started today. First thing I did was break the corners of the HS-609PP. I used my grinder, which did a good job, but got clogged with aluminum pretty quickly. I think my next big investment will be a bandsaw.

The requisite shot of before and after rounding edges.

Then I removed the blue vinyl from the rear spars (HS-603PP) and clecoed the 609s to the 603s. To do this, I needed to increase the radius of the 609s that rests against the web/flange intersection of the 603s. No big deal. Once I did this, they fit great. I didn’t finish the edge prep on the 609s, I’ll do this prior to priming everything. Then, I match-drilled all the holes, including enlarging the HS-708/HS-603PP (inboard rib attachment) holes to #21.

Rear spar reinforcements clecoed to Rear spar channels. It's starting to look like an airplane? Ha.

Next, the directions have you attach the elevator hinge brackets. After match-drilling all of the outboard brackets, they have you sandwich the VA-146 bearing in between HS-411APP to HS-411BPP.

Clecoing the center bearing supports in.

One one side is pre-punced, so you clamp, drill 4 holes, cleco, remove from the spar, and drill the rest of the holes.

Getting ready to drill.

Then I masked off special parts of the VA-146 to prep for priming.

Taped off the important stuff.

And then shoot some primer. (I’m using the rattle can self-etching primer.)

Scotchbrited, cleaned, and primed the center bearing.

Then reassemble and rivet. I found (contrary to some other builders) that the rivets called out in the plans made a great shop head. I think other builders went up a size.  I’m definitely happy with my first six rivets.

The first six rivets.

Here’s everything on the rear spar clecoed back together.

All the hinge brackets clecoed in place.

Then, per the plans, I marked the taper and radius locations for the HS-710 and HS-714 reinforcement angles.

Marked the tapers on HS-710 and HS-714 per the plans.

It was a little late to be running the power tools, so instead, I marked the bend lines on the HS-702 front spar channels. This takes some careful measurement and marking, so take your time.

I also marked the bend lines on the front spar channels. (HS-702)

Then, I strayed from the plans a little. They have you use a 1/8″ bit to create a notch relief hole, then enlarge to 1/4″ using a unibit. I used snips and then a file. The second one turned out better than the first (which I hear is pretty common on everything in the project), and I had some trouble making them look perfect. (I know, things don’t have to be perfect, but it bugs me, anyway.) Biggest lesson learned: cut the flange in the correct place first, then unbend the flange to give you more material to work with. You can see in the top one in the picture below that I didn’t do this, and had to taper into the bend relief notch. (The bottom one below is better, nice straight line back to the relief notch.)

Finished HS-702 shaping with bend relief notches.

Then I bent HS-710, HS-714, and both HS-702s. I created a cardboard template using trigonometry. I took the tangent of 6 degrees. Which is a little over 0.1. (This means fromthe bend line, for every inch you go laterally, the angle will be just over 0.1 inches up.) That’s a little hard to measure, so I took the inverse (to figure out how many inches laterally I need to go for 1 inch up), and got just over 9.5 inches. I have a calibrated 6 inch ruler, so I divided by two, and ended up with mike’s numbers; 4.75″ over, and 0.5″ up.

Now that I have my template for six degrees, let’s get bending.

After trying a few methods in the vise, I ended up just lining up my bend line with the edge if the table, holding a wooden block over the piece, and putting a little pressure on it. If you go slowly, you can get 6 degrees pretty dead nuts on. I laid everything on top of eachother, and it all lined up very nicely.

Lastly, I finished the front spar section by dimpling the HS-702s, and countersinking (first ever countersink!) the HS-710 and HS-714 for the center two holes only. Remember, flush rivets go on the aft side here, so the countersink and the male dimple die go from back to front.

Countersunk HS-710 and HS-714, dimpled HS-702.

A solid 5.5 hours today.

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Practice Kit – Finished

October 4, 2009

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Sunday morning, I managed to finish off the practice kit. Here are the pictures.

Here are the skins riveted to the spar. Notice how I didn't make the jig to hold it to the table.

Here are the skins riveted to the spar. Notice how I didn't make the jig to hold it to the table.

Another shot of the skins riveted to the spar.

Another shot of the skins riveted to the spar.

After the skins were riveted to the ribs and the trailing edge wedge, I rolled the leading edge and clecloed it together. I haven't edge formed the top skin yet, hence the ripples.

After the skins were riveted to the ribs and the trailing edge wedge, I rolled the leading edge and clecloed it together. I haven't edge formed the top skin yet, hence the ripples.

The finished product.

The finished product.

Overall, I am happy with the results. I don’t think they are airplane worthy (I don’t know if I will ever be happy with the final product), but I feel like I am ready to start on the real kit. All of the riveting came out nice, but some of the other aspects (dimpling, countersinking, edge rolling) are still not up to par.

Biggest lesson so far:

1) Go slow, take your time, read the plans, and be careful.
2) The skins don’t look too bad, but I have a feeling there will be too many scratches to polish the final airplane. I’m planning on paint anyway, so I should be okay.
3) Other things, I want to acquire some of the tank dimple dies for the understructure. Some of the skin to rib seams didn’t sit as nicely as I wanted, and I think the slightly deeper dimples in the ribs will accept the dimple in the skin better.
4) Buy a bigger backriveting plate. I just have a 1 x1/2 x 36 inch steel stock. I had to be really careful to keep the rivets lined up. With a wider plate, I wouldn’t’ have had to move the skin around, which caused…
5) …scratches in the skin. Next time I removed the vinyl from the skin, I am going to immediately replace it with painters tape. All of the scratches on the skin are where I removed the vinyl. This can be prevented.
6) Priming. Using the self-etching primer is so easy, I think I may do all of the interior skin next time ( I only primed the rivet lines, where two pieces of metal would meet this time).
7) I need a no-hole yoke for the rivets near the rear of the trailing edge. I managed with a thin bucking bar, but I didn’t like the results. A no-hole would make this a non-issue.

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Posted by Andrew

Practice Kit – Riveting

October 2, 2009

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I started riveting today. I got the skeleton riveted together and back-riveted then stiffeners to the skins.

Skeleton riveted together.
Skeleton riveted together.
Skins back-riveted. Nice, huh?
Skins back-riveted. Nice, huh?

I’ll try to finish up tonight, but I need to figure out a way to dimple the ribs near the trailing edges. I should probably follow the directions and fabricate the special dimpling tool described in the plans. Off to the hardware store for some steel…

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Posted by Andrew

Finished the first assembly in the Practice Kit

September 29, 2009

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Tonight, I finished the first assembly in the practice kit. Only a few notes, and some lessons learned.

Big lessons learned:

  1. The soldering iron leaves a mark if you aren’t careful, be gentle, and go slow enough that it melts the vinyl.
  2. Deburring holes was very easy, even with just an oversize drill bit.
  3. Buy a nice countersink. I faked it with a drill bit, and the results will not be acceptable on the real project.
  4. Less scratches tonight, but still a lot. I need to get some scotchbrite pads and self-etching primer to rehearse the prep and priming phases.
  5. I want to experiment with priming before dimpling. I’ve heard people have had good results (said another way, no bad results due to priming a weirdly angled surface in the dimple.)
I got out the soldering gun and tried my hand at removing the vinyl covering in a straight line.

I got out the soldering gun and tried my hand at removing the vinyl covering in a straight line.

MY FIRST RIVET. It is so beautiful.

MY FIRST RIVET. AN426AD3-3. It is so beautiful.

Three more rivets. I squeezed and bucked with flush and cupped sets. I am using a 4X gun, which means I had the pressure all the way down to 20 psig. It worked really well for the AD3s, but I might need more pressure for the AD4-4s.

Three more rivets. I squeezed and bucked with flush and cupped sets. I am using a 4X gun, which means I had the pressure all the way down to 20 psig. It worked really well for the AD3s, but I might need more pressure for the AD4-4s.

The final (and blurry) product. It's probably for the best that you can't see the fingerprints and scratches on it.

The final (and blurry) product. It's probably for the best that you can't see the fingerprints and scratches on it.

I am very happy that I did this part of the practice kit first. Now I know how to proceed on the real kit, and nothing with drilling, deburring, dimpling, countersinking, or riveting will be new to me, even on the practice kit. (I plan on displaying the practice kit prominently, so it better look good.)

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