RV-3B Dave's in Colorado

[David Paule]

I've been making ailerons. And here's a couple of tips:

1. Drill and rivet the counterbalance to the nose ribs BEFORE riveting the nose ribs to the spar.

2. Drill and dimple and rivet the stiffeners to the skin BEFORE tightening up the trailing edge bend.

Here are the frames - the spar and ribs riveted, with the counterbalances trimmed but not drilled, not riveted or for that matter, not even primed.



The observant reader will notice that I haven't drilled the holes on the bottom of the spar yet.

The lightening holes in the spar were drilled using a hole saw from which I'd removed the pilot drill, replacing it with a round bar. This went into pilot holes previously drilled in the spar web and into a backup wood block that had a lubricated pilot hole and was clamped to the table. That gave me nice clean holes.

Dave

[David Paule]

I've ordered shorter screws than the AN509-8R8 that Van's supplied for the tanks. The AN509-8R8 are too long and that

a) Wears out the nutplates faster than necessary,

b) Sticks into the wing too far, snagging cables and things,

c) Weighs more than necessary.

I ordered MS24694S3.

The aileron counterbalance pipes are primed. I sprayed a bunch of zinc chromate into them and verified that I got full coverage. I riveted them to the nose ribs using AN470AD4-6 solid rivets. The photo will show how I obtained clearance. There simply wasn't room to get a blind rivet tool in there. Refer to point #1 in the post above. I was able to use my squeezer with a 3/8" diameter set. This set is too small diameter for routine work but was perfect for this.



As you can see, I've got to touch up the ends of the pipe a bit with a drop more zinc chromate.

I primed the stiffeners and have cleaned the aileron skin but not primed them yet.

Dave

[David Paule]

This wasn't hard. First I countersunk and primed the holes in the leading edge pipes.



Then I put a male dimple die on one of my yokes and got my trusty 2 lb. ball peen hammer out. Sure looks like I'm prepared to bash the heck out of it doesn't it? But actually using a heavy hammer makes the job easy, since the speed of the impact can be low and still generate sufficient kinetic energy to develop the required strain energy to form the dimple.



And here's a sample of the final dimples. All done with that now.



The ailerons are all dimpled but I still need to trim the leading edges at the inboard and outboard ends.

Dave

[rockwoodrv9]

Looking good Dave. The pipe you are using looks much different than the one in my wings. Is it galvanized?

[David Paule]

Yes, it is. It was furnished with the kit - genuine Van's Aircraft pipe.

Dave

[ppilotmike]

Originally Posted by David Paule

Yes, it is. It was furnished with the kit - genuine Van's Aircraft pipe.

Dave

Hmmm. My kit had stainless steel pipe for the counterweights. Course, I probably paid dearly for them.

[David Paule]

I made a pair of stands to support the aileron. The bottom block prevents the aileron from flopping over, since it's top-heavy. I tried to use the bending brake as a stand as Larry had described in Kitplanes but was unsuccessful with mine, hence these stands.



I added the horizontal wooden batten for a rivet set rest and that helped a lot.



An "L" shaped bucking bar proved the most practical, but in a few places near the flanges the tungsten bar could be made to work.

These rivets on the top flange of the spars, are now complete.



I'm using an under-cabinet light as a shop light. It fit into the aileron and made it easy to see the rivets with an inspection mirror. I checked nearly every one.

Dave

[David Paule]

I had to add some shims to the forward ribs on the top flanges, which was annoying, but still finished riveting the ailerons.

The flap stiffeners are trimmed but not finished.

I've started the airfoil jig to locate the aileron hinge parts to the wing. Since this airplane is not pre-punched, everything needs to be located in space. The jig fits over the wing and has location features associated with it. Hinge location dimensions are with the aileron drawing, the jig is shown in SK-30.

If you're building one of the more advanced kits, the SK drawings are more sketch-like, more informal, than the bigger ones. They're in the manual, not the plans set. They usually describe things like skin dimensions or jig arrangements and given the paucity of information in the plans, are essential parts of the process.

Sorry, no photos at this time.

Dave

[David Paule]

Figured that this would be a good time to see how well the ailerons fit the wing. It's a good time because I haven't started the flaps yet, except for roughing out the stiffeners, and some builders have reported that the flap trailing edge extends aft of where the aileron trailing edge would like to be, without some massaging to make them line up.

I plotted out the dimensions from Dwg 4 on a slab of nice plywood to make the wing template cut-out. The manual says that a paper template is provided, and if it's not, then the outline is drawn on the lid of the wing kit. Of course, neither were supplied with the kit. I got to use a spline and ducks, or I would have if I'd had any ducks. But I didn't. Ducks, in case you didn't know, are real tools. Well, yeah, they're also birds. Here's an article about making your own. Me, I just spotted some weights around and they did the trick. I drew the actual airfoil curve and an outline 1/4 inch fatter than that all around, to allow for carpet.

Since this is an RV-3B and the builder MUST be suspicious, I went and bought a piece of posterboard and made an outline of the actual wing. I used the left tip and cross-checked it to the right tip. Here are the nose and main sections of the posterboard template. If you look closely you can see that they don't match the drawn lines at all.



Also they don't have centerlines.

I used the tooling holes in the wing ribs to determine the centerline positions. Should have done this before I assembled the wing!

Once I got things lined up and checked it didn't look all that bad.

Here's a picture from the plans showing how the fit is supposed to be. The aileron spar should be 3.75 inches aft of the wing's rear spar, and the aileron, trailing edge to spar, should be 9.25 inches - and that's okay.



I drew out a template on the posterboard for the aileron and it matches the actual ailerons nicely. Unfortunately there's an issue: The wing skins are too far apart for the aileron to fair properly. Look closely at this picture:



The aileron spar is located the proper distance aft of the wing's rear spar. The aileron and wing centerlines are lined up. The aileron trailing edge is .40 inches aft of where it should be, but that's not a serious issue. Look at the top skin (The wing section is shown upside down so it's on the bottom) and the bottom skin (shown on top). They sure don't line up with the aileron, do they?

There's the problem.

Dave

[pekuba1610]

Dave,
I'm not sure if this might help you, recently I read something in the "27 vears of the rv-ator" regarding a similar problem with ailerons which do not line up perfectly with the trailing edge of the main wing skin; see page 122 of the PDF version in the wing section.

WING SKINNING
Check Those Flange Angles [2/93]
by Van
Several reports of .....

Peter