scuffing | Andrew's RV-7 Build Log

I Hate Making Stiffeners

August 14, 2011

After last night’s bummer of a screw up (mis-drilling the aileron spar reinforcement plates), I woke up in a cold sweat.

I thought I was going to have to order four more little plates, just to pay some ungodly amount of shipping from Van’s to here.

Then I rememberered the “Trim Bundle” than Van’s sends you. I think there may be some 0.040″ in there.

Sure enough (after measuring, finding some 0.045″, then taking the blue plastic off, and seeing that it was really 0.040″), I had something to continue working on the ailerons.

I went ahead and marked some 0.032" that I found, as well.

After some measuring, marking, and trimming, I have 4 new pieces.

Old and new.

Instead of clamping these to the spar, I decided to just use the old pieces to matchdrill the new ones.

I've clamped the new pieces under the old ones, but in the OTHER orientation.

After some drilling, scuffing, edge-finishing, and marking, I had four new reinforcement plates.

Like new.

I clamped them to the spar, and marked the appropriate holes for countersinking.

There are two holes on the outboard end of each spar, too.

After that, I looked around, and figured there was nothing else to do except start some stiffener fabrication.

I hate making stiffeners (see title of post for emphasis). It takes forever, there are pieces of aluminum flying everywhere, your hands get cut up, but, it’s necessary.

After about an hour of cutting, filing, snipping, edge finishing, and scuffing, I have 32 beatiful stiffeners to go into the aileron skins.

8 on each of the upper and lower surfaces of each aileron.

That sucked, but as long as I can salvage the rudder stiffeners, I think those were my last stiffeners!

2.0 hours.

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Leave a Comment » | Wings | Tagged: Drilling, edge finishing, scuffing, Stiffener, Stiffeners | Permalink
Posted by Andrew

Prepared Right Leading Edge Rib Number 4

April 28, 2011

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(sarcasm)Whoa, what an exciting night!(/sarcasm)

I managed about 26 minutes in the garage tonight.

The picture below tells the short story. I grabbed leading edge rib #4, and deburred it, then redid some of my fluting, made sure the flanges were 90°, then went ahead and scuffed it with a maroon scotchbrite pad.

Maybe this weekend I’ll get the 5th and 6th ribs done, then get them primed and riveted to the leading edge rib.

From left to right: Deburring, Fluting, Straightening, and Scuffing.

Rounded up to 0.5 hours.

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Leave a Comment » | Wings | Tagged: Deburring, fluting, scuffing, straightening | Permalink
Posted by Andrew

Left Elevator Counterbalance Skin

July 13, 2010

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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!

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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

Primed Right Elevator Skin

May 19, 2010

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Well, it was a short night in the shop tonight, but after almost a week without building, it was a productive hour.

All that’s remaining before riveting the right elevator together is to finish up deburring, dimpling, and priming the right elevator skin, and doing the same (as well as getting a big enough dimple for the counterbalance attach screws) in the counterbalance skin.

First thing, I grabbed an oversize drill bit and started deburring.

I still can't bring myself to buy a deburring tool. Maybe I'm being stupid. (Who got sawdust all over my right elevator skin?!)

Then, I realized that the holes on the very front edge of the skin (for the pop rivets after you bend the leading edges together) will be very difficult to deburr if I wait until after bending to matchdrill them. I decided, like on the rudder, to drill and deburr them now.

Just making sure the #30 bit is the right bit.

After drilling, this looks like it will fit the bill when I am ready to start riveting the leading edges together.

After getting all of the holes deburred, I grabbed my scotchbrite pad and got to work scuffing. I grabbed an intermediate shot so you can see what I am doing.

Scuffity-scuff scuff.

After scuffing, I cleaned everything up with MEK (because it’s harder to clean well with the dimples) and started dimpling. Here is the inboard edge of the right elevator (which is upside-down on the table) after dimpling with #40 dimple dies.

I love dimpling. Don't know why... (Whose palm prints are all over my elevator skin!?)

A before and after shot of dimpling.

Please no comments on the lack of edge finishing here. I did all the edge finishing after this step.

Like I said, after edge finishing and another wipe-down with MEK (and the requisite drying time), I put the skin up on my garbage bins and shot some primer on the interior surfaces. If you look closely, you can see where I have left the blue vinyl on the inside of the skins. That is where I don’t want any primer (weight savings) after I am done. When the skin is dry and ready for riveting, I’ll pull the vinyl out and be left with nice shiny, untouched aluminum.

I cant wait to rivet this stuff together. I am proud of this elevator.

One little hour, but good prep work for riveting soon!

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Leave a Comment » | Empennage | Tagged: counterbalance, Deburring, Dimpling, Elevator, matchdrill, MEK, Priming, rivet elevator, scotchbrite pad, scuffing, skin | Permalink
Posted by Andrew

More Drilling, Deburring, Scuffing and Dimpling

May 9, 2010

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After we got back from my first Pilots N Paws rescue, I was excited to keep working on the airplane.

I needed to start on the tip rib and counterbalance rib, so I needed to get the holes in the counterbalance to final size (#12, for a An509 screw).

I had some trouble awhile back with drilling the counterbalance holes to final size, and I don’t have any boelube, but i figured any lubrication would work better than none, so I poured some air tool oil into the holes and tried again.

This time, it worked much better. (I still got stuck a few times, but I didn’t come to a grinding halt like I did last time.)

Here's the counterbalance after drilling to #12.

I clecoed the counterbalance skin back onto these two ribs, inserted the counterbalance, and matchdrilled through those to make these holes in the ribs.

Nice job with the blurry picture, right?

Next up, deburring.

There's my trusty deburring bit.

Then scuffing.

Bottom rib (counterbalance rib) is scuffed.

After deburring and scuffing the tip rib, I dimpled all but the last 2 holes on the top and bottom of the rib.

The two non-dimpled holes are not shown here. I'll have to get the countersunk steel plate out to get those.

Next, I clecoed the counterbalance skin on the right elevator skin and marked with a permanent marker where I wanted to scuff and prime. Some of the edges here have to be broken to make the skins seam from spar to coutnerbalance skin a little smoother. More in a later post.

Above this line, the right elevator skin overlaps, and will need a coat of primer.

Then, out with the trusty blue tape.

Taped and ready for scuffing.

Then, I pulled out my #8 dimple dies (don’t have #10 dies, which are the correct dies for a #12 hole and AN509 screw) and dimpled the counterbalance skin. The countersinks on the right are the correct size. I need to figure out how to dimple the skin on the left a little more.

After this shot was taken, I screwed the correct screws into the assembly and tried to tighten them down to dimple more, but I didn't want to strip anything, and it wasn't really going to work.

I’m going to research how people did this without #10 dies later.

No rivets set, but a good hour on the plane.

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Leave a Comment » | Empennage | Tagged: Boelube, clecoed, counterbalance, Deburring, Drilling, matchdrilled, prime, Rib, right elevator, scuffing, skin, skin ribs | Permalink
Posted by Andrew

I Love Tungsten (Started Riveting Right Elevator)

May 8, 2010

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Well, this morning, the girlfriend ran some errands, and I got my house chores done early, so I headed out to the garage to make some loud noises. Recently, I’ve been taking one component at a time from drilled through primed. It make my work sessions less boring (not a full day of deburring lots of parts, but rather one day of drilling, deburring, scuffing, dimpling, cleaning, and priming one part).

Anyway, today, it was the right elevator spar’s turn.

First, deburring. There's my oversize drill bit spun in my fingers.

Then I put a nice scuff on all sides and edges.

Scuffed and edge finished.

Then, I broke out the tank dies to do some dimpling.

I love these dies. Such high quality.

I know you guys have seen tons of dimples from me, but I still take pictures.

The male side.

And the female side. Apparently I have not edge-finished yet.

After finished dimpling, I grabbed this shot down the length of the spar.

Right elevator spar, dimpled.

I forgot to take a picture of the countersinking I had to do on the front (flanged) side of the spar. The spar needs to be countersunk to hold the flush rivets attaching the E-709 Root Rib Right. The elevator control horn fits over them.

Then, inside for cleaning and back outside to the paint booth.

One side primed.

While I was waiting for the back side of the spar to dry, I went ahead and pulled the vinyl off both sides of the E-713 counterbalance skin.

The vinyl comes off a lot more easily when it is warm out.

Then, I got the other side of the spar primed, and prepped for some riveting. I had already prepped and primed the two reinforcement plates that get riveted to the back of the spar.

There's my new tungsten bucking bar.

Here’s my setup for spar riveting.

You can't see the reinforcement plate, but those clecos are holding it on.

After 8 rivets, all I can say is…WOW. I love this tungsten bucking bar. 8 perfect rivets. With the older, and smaller, bar I was using before, things were always bouncing around, and my hand was vibrating, etc. With this bar, it is so easy to rivet. I should have bought this at the beginning of the project.

Wow, these are amazing shop heads.

Here's the other side.

I spent about 2 minutes just staring at the bar. Amazing.

I thought I would show you my grip.

8 more, also perfect.

Wuhoo, this bucking bar is great!

And, the other side of those.

I wanted to buck these, but I thought it would be better to squeeze them.

The spar to E-709 rivets.

These are the flush rivets I was talking about earlier. Of course, when the primer is only 30 minutes old, and you try to clean up some smudges with MEK, the primer will rub off. Duh.