Drilled Right Flap to Wing

January 17, 2012

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Warning: My blog is not a drinking game.

But, if it were, and you had to take a drink every time I logged some build time…

You would not be very drunk.

Hello, everyone. In case you forgot (has it been two weeks?), I’m Andrew, and I’m building an RV-7. Today, I actually got a lot done on the airplane.

It was really only a few drilled holes, but they were important for two reasons.

1) Everyone freaks out about drilling the flap to the wing, and

2) I drilled the flap to the wing prior to the flap actually being riveted together. I know it’s out of order, but I made the decision that the flap was super-sturdy and aligned when it was clecoed together.

(Also, it’s late, and I’m at the step where I need to make a lot of noise with the c-frame, so drilling was quiet by comparison.)

Let’s get to the pictures (and video!!!!).

First up, I wanted to knock out some of the smaller tasks that need to be completed before moving on to priming and assembling. First up is to cut down one of the spar brackets to final size.

I wish I had take a picture of the original piece, but here’s after the cut.

I'm still using my jigsaw for these.

After some scotchbriting.

Then, I moved on to dimpling the spar (I had deburred the holes a few centuries…I mean weeks ago.

Dimple holes. No biggie.

Also, I countersunk the appropriate holes for the nutplate around the flap rod-end attachment hole.

Standard flush rivet in the background, an oops rivet up front.

Here’s where I made a big decision. I was looking for something quiet to do, so I decided to cleco up the flap and just set it on the wing.

First, I needed to get the lower outboard skin clecoed in place.


Then, I just clamped the flap in place.

Whoa. Looks cool. Like a real wing!

At this point, given the sturdiness of the flap, I decided I could drill the flap hinge to the wing. Even if I totally hose it up, all I’d have to do is order a new flap hinge. (I can order that along with my new RUDDER, which I still haven’t accepted as needing replacement yet. What was that….a year ago?)

Anyway, let’s just clamp everything in place and see if it still makes sense.

Looks like I need 1/4."

Two 1/4″ drill bits, two¬†Popsicle¬†sticks, and two clamps later, I had a flap ready to be drilled.

For the record, this was not the first, nor the last, of the many attempts at a) a good picture, and b) aligning the trailing edges.

Looks pretty good though. Not perfect, I need better alignment along the trailing edge.

For most of my alignment, I used my 4′ level on the trailing edge, then used my iPhone level app to get down to the degree.

Here I'm making sure the transition lines up, then I'd move the level to the flap, measure the absolute angle, then move it to the aileron, and compare the absolute angle.

After about 10 iterations, I drilled the first hole.

Sorry about the blur. The good news is that it's still making sense and aligned.

After working a little down the line (Drill, cleco, measure, measure, measure. Drill, cleco, measure, measure, measure), I stood back to take this picture.

Looks straight to me.

Almost forgot, another one of the measuring tasks was to measure the gap between the flap skin and the lower wing skin.

0.2965" the whole way. Can't get any better than that.

A little interesting note…the flap brace didn’t perfectly line up with the lower wing skin, so I had to improvise a little.

I didn’t want to be matchdrilling the hinge through two other holes that didn’t line up, so I wanted the whole flap brace perfectly in position prior to drilling. I grabbed the smallest -AD3- rivets I had and stuck them in every other hole to act like clecos (I could have use clecos, but that pushes the hinge away from the backside of the flap brace.)

This kept my skin and flap brace holes aligned all the way down the row. As I’d get close to the next rivet, I’d just pull out the rivet.

This worked great for me, but your mileage may vary.

Of course I forgot to take a picture when I was done. I did “lower” the flap all the way to measure, and then mark, the three hinge eyelets I will be using for future hinge pin access.

I've marked them for future modification for the hinge pin insertion, but you'll have to wait another day for that.

Here are some of my “after” pictures.

Looks straight to me.

Looks so good.

Like a real wing.

I was so excited about it, I had to get a video.

So, 2 very productive hours. I’m sure some of the builders out there will insist that all will go to hell after I rivet the flap together, but I don’t think that’s going to happen. So far, all the match-hole kit parts are lining up perfectly, and the clecoed flap is very sturdy and true.

Now, I need to get back to prepping the flap for final assembly. But first, I need sleep. Goodnight.

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