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Aileron Hinges

January 23, 2012

So this weekend I spent quite a bit of time working on the aileron hinges.  As the name implies these are the load bearing parts that connect the ailerons to the wing.  Of course the aileron is responsible for letting the plane rotate longitudinally (from tip to tail) so that it can turn either left or right.

This project is a kit of parts that comes in a separate bag.  Here are the parts necessary to build the hinges for the right wing.

Lots of pieces and parts

It doesn’t look like much, but these parts are pretty important.  If made incorrectly the plane may fly with a bias one direction or another, or worse yet could fail in flight.  We don’t want that.

Every task you perform while building an RV starts with assembling the parts to make sure that you have all the parts, they fit correctly and that all the holes match up.  Its also allows the builder to study every detail.

Notice that I have all the parts marked with the part number in blue sharpie.  Eventually I’ll know each of these parts just by looking at them, but for now the markings are important.

Now that they are all assembled I have to get them on the wing and make sure they fit the way the plans say they should.  So I grab a couple of clecos and get to fitting.  This is made a bit more challenging because the wing is upside down, but the plans are right side up.  Every time I refer to the plans for something I have to conciously think about how being upside down might effect what I’m doing.

Here's one of the hinges bristling with clecos and attached about mid way on the span of the rear wing spar

On this next hinge bracket I have made a horrible horrible mistake.  Had I just blindly assembled it and attached it to the wing I would have been removing it later and disassembling it because the ailerons wouldn’t have fit.  Because this is just  a mock up and test fitting it is no biggy.

Here is the bracket at the end of the wing.

I've made a big time boo boo with this hinge.

If you notice, there is a line of holes that has neither clecos or anything attached to it.  Thats because in the 1st picture of the set the angle bracket that connects everything to the spar should be even with that set of holes….its hard to explain, you’ll see another picture later that is correct.

Ball joint for the hinge.

The next steps I didn’t take picture of, it was just me match drilling all the holes.  After de-burring I prepped everything for primer.  I washed the parts and got the primer applied and hung everything to dry for 24-hours.  In the ensuing time I read ahead in the instructions.  The next thing I’ll be doing is attaching the aileron gap seal and the flap brace, so I might as well prep them.

One of the things that haunt you throughout the wings process is the fact that whatever you’re doing on the right wing, you’ll have to do on the left wing too.  Whenever possible, I try to do both left and right prepping at the same time.  In that vein I went to my attic and retrieved my flap brace and aileron gap seal for both left and right.

Parts scuffed and ready for cleaning and priming

I spent about an hour deburring and edge prepping.  Those holes in the flap braces were very sharp.  Once they were ready I mounted them on the trailing edge of the wings and got everything match drilled.  Because these parts don’t hang in the wind, they don’t need flush rivets.  No flush rivets, no dimpling.  Yea! So once the match drilling is done, I just did a quick deburr on the parts and headed for the sink for washing.  Once they were washed and dried I primed them and hung them to dry.  That was enough for one day.

When the rooster crowed I was up and getting coffee then out to the shop.  I got the hinge bracket parts down from the clothes line in the shop where I hung them to dry.  Nice and dry ready to go.

Step one, make sure that little bearing is pressed between the parts and then countersink a couple of holes.

Pretty countersinks for the flush rivets

Since these are flush heads I can back rivet them.  I get out my gear and start back riveting, but they only go so far before I just cant squeeze them anymore.  I’ve had this issue before with the 1/8″ rivets.  My work bench flexes too much and I just can’t maximize the power in the gun.  So to remedy things, I put my back riveting plate on the concrete floor of the garage and the results are much better.

See if those rivets gives me a hard time with planet earth backing me up!

Text book shop heads

Factory heads are just where they are supposed to be.

I’m not sure why those heads have to be flush.  I guess it will become clear later.  I’m guess that a round head would interfere with the aileron travel somehow.

Now I have to get the bracket installed.  This is the piece that will mate the hinge to the spar.  These rivets are not flush, so no back riveting this time.  I have to use the round heads. I first need an extra set of hands.  My bench vice will do nicely.

The bench vice is pressed into action as another set of hands

Notice the wood shims.  I used those to keep the vice jaws from marring the metal.

Bracket is installed nicely

Next task, getting everything attached to the wing.

Between football and lunch and a trip out with the family, this has taken most of the day for the two brackets.  After dinner I get to work attaching the brackets to the rear spar of the wing.

Yuck that thing is dirty. Not only that the rivets arent right. 😦

Nicely set rivets on the outside hinge

Ok…ready to see what I messed up.  The top picture is my original mock up.  The bottom picture is after I noticed it and did it right.

I've made a big time boo boo with this hinge.

This one was right

Here is detail of the area I messed up.

Notice how the outer plate covers the end of the spar.

I was destine to find this mistake anyway.  Fortunately it happened now, not when I was trying to fit the aileron.  That would have sucked.  🙂

That’s it for my weekend.  I’ll spend some time this week assembling these same parts for the left wing, so its done when the time comes.

Oh…one last picture.  This is fatigue.  I was tired when I did this and now I have to fix it.

These are smeared rivets. They are the devil to drill out.



From → Ailerons, Build Log, Wings

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