Started on the Ailerons

August 13, 2011

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Well, Joe and I haven’t been able to find a good time to come over and get the last of the wing rivets done, so for tonight, I’m going to move on to something else. Even though I could go back and continue working on the left wing, I think instead I’m going to start on the ailerons and flaps. Instead of just the right aileron and right flap, though, I’ll just go ahead and build both sets.

First, the ailerons. Here’s a plans change picture, for your amusement.

The ailerons!

First up, let’s start collecting some parts. Here are the aileron spars.

One withe blue plastic, and one after I'd removed it.

Then, I gathered up some nose ribs, the hinge brackets, and the spar reinforcement plates.

Aileron parts.

Following the directions (although I’ve skipped the stiffener-fabricating part), I lined the edges of the reinforcement plates up with the ends of the spars, and centered them vertically. They seemed to go only one way (they’re a little rectangular).

(Does that sound a little ominous? Keep reading.)

After some matchdrilling, I stepped back for another picture.

All four reinforcement plates drilled.

Then you stick the hinge brackets on, and drill up to a #12 for some AN3- bolts.

Looking good. Everything's aligned.

Then, I took everything apart, and noticed that my edge distance was not so great. After rechecking the orientation of the plates, I realized that I had initially lined them up correctly, just to assume that they were the wrong way (it didn’t look like they would fit). I flipped them 90° and drilled.

I found an awesome online tool to do this for me. Hilarious, right?

I held them up the correct way, and sure enough, there’s room. Bummer.

Just so I could end on a high note, I found the aileron ribs, and pulled the blue plastic off.

Some aileron ribs.

I clecoed them to the spar, along with the nose ribs, so that I could see something that kind of resembled ailerons.

Yup, these look like ailerons.

1.0 hour.

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Right Rear Spar Doubler and Reinforcement Fork

September 8, 2010

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The next step on the rear spars is to trip the W-707D and W-707G Rear Spar Doubler and Reinforcement Fork to size.

These parts are shared between the RV-7 and RV-8 (and maybe more, I’m not sure), and must be trimmed if you are building the -7.

This is a tricky trim job, though, because many people have future troubles with drilling the rear spar to the fuselage and maintaining the required edge distance for the hole in THESE PIECES.

It would be best not to overtrim, and leave even less margin than what is already there.

The plans and construction manual both point to Dwg 38, which is of course not included as a full-scale sheet in the wing kit, so I got out my preview plans and started staring.

Even though I’m only working on the right side for now (will bring the left wing up to the right side’s progress when I get the replacement spar from vans), I’m going to do both sides of this now while I’m all mind-prepped to do it.

A snapshot of the applicable portion of Dwg 38. Looks like I should start measuring and marking. (No cutting yet, though!)

Keep in mind here that you measure from the edge you are about to start cutting away, so once you start cutting there is no double-checking your measurements.

Of course, I'm being dumb by doing the right side first (left is shown in the drawing above.)

Here are both lines drawn, measured, double-checked etc. It's still all making sense, so that is a good thing.

The bottom cut off. (For you OCD types, I realize I should have made the other cut first, which would have been a little less cutting overall, but oh well).

I decided to cleco the two smaller pieces together first, then transfer the lines to the bigger forks, and do those separately.

Ready to transfer the lines.

Of course, I didn’t get any in-progress shots of the fork cutting, but it went well. I then clecoed the left and right assemblies together and grabbed this shot after a few passes on the scotchbrite wheel.

At the end of this project, I am going to go back and count how many toes ended up in all the pictures. Here's...{counting}...6 more.

After some time on the scotchbrite wheel, I have two ready-to-cleco parts.

Nice and scuffed.

Then, I clecoed the doubler plate and reinforcement fork to the right rear spar and started matchdrilling.

Matchdrilling.

I had a hard time deciding if I should enlarge some of the rib attachment holes in the fork and doubler plate to final size, and I decided I would. I couldn’t find anyone who said it would be a bad idea, and now I’ll get to deburr and prime all of the rear spar components.

I did leave the majority of the rear spar “future” holes alone, though. I guess per the directions (indirectly, just in step order), I’ll drill those after priming the rear spar.

Here's a picture from the backside (actually, front side) of the spar.

Of course, I was careful to mark and enlarge to #40 the flange holes that need to be dimpled now (the reinforcement fork prevents the female side of the dimple die from getting behind these holes).

I didn't actually dimple, though. I need to leave something for tomorrow.

After taking everything apart and deburring holes, I have a few pieces ready for priming, and a rear spar with some remaining deburring before priming.

I scuffed the rear spar where I had already drilled and deburred to help remind myself what I have left to deburr.

Today’s hour was a good one; a few things ready to prime, and just one deburring and priming session away from being able to rivet the rear spar assembly together.

I need to go buy some more Napa 7220 Self-Etching Primer.

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More Trim Tab Hinge Drilling

June 27, 2010

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After a motivating afternoon actually getting to sit in an RV-7, I got back to work on the trim tab. Here, you can see my new 3-foot-long MS20257-3 next to the old (and not perfectly aligned) 18-inch MS20257-2 from Van’s. It’s a little wider to give me some more edge distance.

New on top, old on bottom.

First thing, I got the new piece cut to length. It ended up being a little shorter than 18 inches… I made sure the elevator side had a hinge “ear” on each end.

I eye-balled the hinge pin length a little long. Van's tells you the hinge pin they ship with this kit is not long enough to bend and safety to the elevator, and that they'll ship the real one in the fuse kit (or finish kit, can't remember). I guessed it was about 2 extra inches I needed for the bends and then cut the hinge pin.

Then, I spent a good amount of time Just getting everything lined up. I am a little frustrated at this point, because the supposedly straight line of holes on the elevator is not parallel to the supposedly straight line of holes on the tab. This means that with the trailing and inboard edges of the tab aligned with the elevator, the gap between the leading edge of the tab and the elevator cutout is smaller near the root than the tip of the tab.

Inboard and trailing edges aligned perfectly.

Here's my inboard edge.

So, again, I strayed from the directions. I held the hinge in position, making sure the actual pin was directly in the middle of the gap as shown in the picture above at the root (smaller gap) edge and at the outboard (larger gap) edge. I figured as long as the pin was directly centered, I’d be okay. Then, I clamped it in place, and marked a single hole (see below) for drilling. I couldn’t pick the edge hole, because it was covered by my square.

On the drill press, ready to drill a single hole.

I repeated this for another single hole on the tab side, again, making sure the hinge pin was perfectly centered between the two surfaces.

Two holes drilled and clecoed.

At this point, it was close to being locked in place. I did notice that these hinges are somewhat flexible, so while I marked every hole for drilling, I really only drilled a few more before clecoing it in place and match-drilling the rest of the holes.

(A more technical side note…because I upped the hinge size to a MS20257-3, the hinge was too wide to fit inside the radius of the elevator and trim tab spars. When matchrilling, I had to change the order of the skin, hinge, spar to accommodate the extra length, then I went back and ripped a small (1/16″) strip off of the hinges so they would fit nicely in the radii of the spars.)

Here are my feet, ready to keep going on the hinge.

Fast forward after some drilling noises, and here are the two halves, each clecoed to their surfaces.

Ooh, looks good.

I still have a little bit to trim on the elevator skin, but I trimmed enough to allow some motion today.

You can just see the rounded (so it slides in easier) tip of the pin in this picture.

Here’s a closeup of how much extra pin I think I need to make the bend forward (along the spar flange) and then down (along the spar web) to a small safety-wire hole I have yet to drill to safety the pin in place.

Man, that thing is long. (TWSS)

After getting the pin in, I took out every other cleco on each surface so I could move it back and forth.

Neutral.

Tab up (or elevator down trim).

asdf

Tab down (or elevator up trim).

After dancing around for a little due to how great the tab looks on the elevator (and how well-aligned it is), I took the thing apart, ripped the 1/16″ off of each hinge half, and fired up the scotchbrite wheel to clean up all of the edges.

Look on the lower right part of the tab. That little angled cutout is so the hinge hides nicely under the tab skin.

I figured now would be a good time to finish match-drilling the tab. Let’s go find E-718 and E-717.

There they are!

Apparently I thought it would be a good idea to show you my scotchbrite wheel. That little groove is just getting to the right size so I can run the edge of a piece of aluminum down it and it perfectly rounds both sides.

I love this thing.

Back to the tab horn. The directions would have you use the clevis pin (don’t have this yet because I haven’t ordered the tab motor) to line up the two horns. How about two perfectly-fitting #30 clecos?

For balance purposes, I put one on each side.

Three of the holes are pre-punched, and two are not.

Just before match-drilling everything.

All done.

All done. (From another angle.)

I was planning on at least polishing the tab for now, so I marked off where the horn sits. I’ll prep and prime this little area under the horns, but I’ll leave the rest polished. (The bottom of the tab is going to be a good place to teach myself how to polish aluminum.)

The horn location, marked for future priming.

Whew. That was a good two hour work session today. It was like a sauna (more like a steam bath…this is the south!) in the garage today. I kept sweating on the airplane. (People say they put blood, sweat, and tears into their projects. I’ve got one covered, and will undoubtedly bleed and cry because of the project sometime in the future. Have to have something to look forward to, right?)

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$6.48

June 22, 2010

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After getting stung by a wasp two times in the last two days trying to mow the lawn in the backyard, I gave up (shows determination and perseverance, huh?) and retreated to the comfort of my garage for some airplane work (the floors can wait until tomorrow).

Back to the tab. Before I do any more cutting on the elevator, I want to get the tab hinge drilled so I know exactly where the outboard edge of the tab will swing. I am doing this before they really tell you to in the directions (the directions have you actually finish the elevator, then start working on the tab.

Anyway, you are supposed to draw a line 1/4″ from the loop edge of the tab, and first matchdrill that to the tab. (I started with the elevator side, which eventually bit me in the ass. Read on.)

I decided to mark both sides with the 1/4" line. Hmm. Doesn't look like there is going to be a lot of edge distance.

Then, I took the hinge apart (you can see the hinge pin in the next photo) and clamped the elevator side to the elevator, lining up my 1/4″ line in the first prepunched hole, and aligning the first hinge loop where I thought it looked good (making sure this fit with the plans).

Hint: If you take apart the hinge, you can easily clamp the hinge half to the elevator (and tab, with the other half).

Next, I lined up the outboard side. This tab hinge is nice and square with the edge, and with the holes.

Let’s drill!

Here are 6 holes drilled (I'm working inboard to outboard).

All done with the elevator side.

Next, I reassembled the hinge and spent a few minutes just kind of getting everything lined up.

I wish this were the final product, but this is just me mocking things up before drilling.

With the greatest of coordination, I managed to hold a straight-edge against the inboard edge, line up the inboard pre-punched hole with the 1/4″ line, and line up the trailing edge of the tab with the trailing edge of the elevator, AND take this picture. Boo-ya.

Looks good so far.

Then, I drilled the inboard hole. The inboard side is perfect. (Can you tell that some other part may not be by the way I phrased that?)

If you look closely (lower left corner), you can see that the tab trailing edge is further aft than the elevator trailing edge.

I was pissed. I lined up the hinge with the elevator edges and holes, and with the tab edges and holes. This means that either the elevator or the tab isn’t perfectly square.

I thought about just moving the tab forward, but then there would be slightly different distances between the skins from inboard to outboard. I measured it…it would have been about 1/32 difference. No one would have noticed except for me.

But…I can’t leave it alone. I’m going to reorder the hinge and try again. This time, I’m still not going to follow the directions. If you make the hinge perfectly square to the tab, it’s going to be off on the elevator side. I’m going to have to split the difference between both by first clamping the tab in perfect position, then clamping the hinge in place and matchdrilling a few holes.

Admittedly, I should have followed the directions by starting with the tab edge, but it wouldn’t have mattered, it still wouldn’t have been a perfectly square hinge line after I was done.

The tab hinge is AN257-P2 according to the materials list in Section 4, but the part shows MS20257-2.

I also think, given my edge distance worries (must be okay because it is per the plans? I don’t know), I am going to order the MS20257-3 (or AN257-P3, which is 1 + 1/4″ wide instead of 1 + 1/16″). I checked with Van’s, and they want $9.70 (plus $4 handling, plus $12 shipping or something) for an 24″ piece of AN257-P3.

I checked aircraft spruce, and they wanted $4.75 for a 3′ piece and $1.73 shipping via USPS.

Which one do I choose?

Duh. $6.48 for my first re-ordered part. Bummer. (It’s better than a $60 elevator skin, though!)

Here are my edge distances.

I love this kind of building. Thinking, playing, mocking up, etc. The normal matdrilling dance gets old…this is the stuff I really like.

1.0 hour tonight. Frustrating, but fun.

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