blue vinyl | Andrew's RV-7 Build Log

Left Elevator Counterbalance Skin

July 13, 2010

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

Left Elevator Stiffeners, Part Uno

May 26, 2010

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Another quick night in the shop. First thing, I fired up my 6″ grinder (with a scotchbrite wheel attached) and edge-finished half of the stiffeners. After that (about 45 minutes of the total 1 hour in the shop), I started the stiffener to skin drilling dance.) In this first picture, I’ve just placed the elevator trim backing plate in plate for the effect. On the right, my first two holes drilled (into a sacrificial piece of MDF) on the bottom of the left elevator.

Bottom of the left elevator, working from inboard to outboard.

Here are three of the shorter stiffeners drilled, and the forward most hole on the last four drilled.

3 done, 4 to go.

All of them drilled.

Next, I uncleco the assembly from the table, and recleco just the front and back holes of the stiffener so I can flip the skin over to match-drill the last hole (it’s prepunched in the skin, but not the stiffener on a couple of the stiffeners). Then, I traced around the stiffeners with a sharpie, then pulled them off and clecoed them to the outside of the skin, again, to trace them with a sharpie. This will help me figure out where to remove the blue vinyl later instead of just guessing (like I did with the right elevator.

Of course, the stiffeners don't go on the outside of the skins, I am using them to mark the outside of the skin for devinyling.

See? All traced.

The inside, too.

lastly, I removed the stiffeners and marked them before prep for priming.

B2 is upside labelled upside-down. Maybe I should remake the stiffener. /sarcasm off.

One boring hour today.

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Leave a Comment » | Empennage | Tagged: blue vinyl, edge finished, Elevator, Grinder, match-drill, MDF, Priming, right elevator, Scotchbrite, stiffeners. Drilling | Permalink
Posted by Andrew

Riveted E-615PP Trim Reinforcement Plate

April 6, 2010

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WUHOO, tool order arrived!

3 things in the order, $154.90. Ouch.

Also included was this AWESOME sticker.

Where should I put this?

Here?

On the airplane? no.

Finally, the air compressor won.

Decorated air compressor.

Look at that beautiful tungsten bucking bar.

Old and new.

Also, I got two more dimple die sets. #6 and #8, on the right.

Just for comparison. #40, #30, #6, #8. Still need a #10.

Alright, back to work. First up, using the #6 dimple dies on the E-616PP Trim Cover Plate.

Nicely dimpled. I don't think it matters that you take off the blue vinyl. Maybe that was a bad idea.

Here’s the bottom side (top side when mounted on the bottom of the elevator on the airplane).

Peeling off the blue vinyl.

Then, edge finished and scuffed for priming. I’m going to wait to prime this until I can actually by the electric trim motor since you have to drill more holes. Just thinking ahead: can I countersink and use NAS rivets for the trim motor mounting brackets? Nope. These are pretty structural (hold the motor, and therefore the trim tab, in place.) I’m sure those directions will confirm the need to dimple. I’ll need to dimple E-616PP and the brackets that are used to attach the trim motor.

Ready for priming, except for all of the extra holes I have to drill, deburr, dimple, and rivet.

Same deal on E-615PP.

Ready for priming.

On the fancy priming stand.

After shooting primer to one side of E-615PP, I decided to add 4 holes for each of my new dimple die halves.

4 holes drilled.

Tada.

7/32″ seems to work well for holes in a home-made dimple die holder stand.

7/32" is a good size hole for these.

Then, I shot primer on the other side of E-615PP. While I waited for that side to dry, I edge finished E-616PP.

Look at that nice edge. I love the scotchbrite wheel.

Now that E-615PP is dry, let’s do some riveting! I grabbed the K1100-06 nutplates (or platenuts as Van calls them) and the 14 required rivets. Remember from March 28th, I am using NAS1097 rivets here.

I am going to be using NAS1097 rivets here (smaller head than AN426 rivets) so I can countersink (instead of dimple) the holes here. That saves me from having to dimple the nutplate ears, which will save me a lot of hassle.

I finally found the rivet callouts.

I thought that because I countersank (verb tense?) the reinforcement plate that the 3.5 would be way too long, but the -3 was definitely too short. I grabbed 14 NAS1097AD3-3.5 rivets.

-3.5 (length) should work here.

I put all of the nutplates in with a single cleco and a single rivet, taped into place before starting to squeeze them. I hindsight, I should have backriveted these. So dumb.

Half of them done.

Then I did the other half.

Nice and flush. There is one that is almost proud, but doesn't affect the cover plate, so I may not try to muck it up further by drilling it out. We'll see if I can sleep tonight.

Once I got those 14 set, I grabbed the An507-6R6 screws and got the cover plate screwed on.

Ready to screw down. see in the lower left where the shadow under E-616PP is a little bigger? The dimpling kind of warped the plate. I'll have to try to coax this flat again.