Lacking Balance

Went to the AOPA fly in at Anoka County Airport today. Was pretty cool and bigger than I thought it would be. Few airplanes flew in because of weather and winds. But still some neat things to see and many familiar faces.

When we got back we spent some time in the shop. We jigged the new 1/2″ steel rod on the ailerons to verify that they balance, and they do now. It would be nice if they balanced a bit more since any coating (primer/Paint/filler) adds weight that must be balanced. I will have to sand quite a bit before painting and be careful not to add too much paint. We probably will sand more after we get the weight glassed in place, so that eventually we can paint the ailerons.

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Here you can see the aileron balanced. It has to be between bottom skin level and top skin level.

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And you can see we added foam back to fill the gap between the balance rod and the aileron. Next will be to add one ply of bid over that to lock it in place.

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Then we took off the elevators to balance them. At first we thought they were miserably out of balance as well. But then we rigged up a more accurate balance jig. Simply two plates of steel clamped vertically ensuring they were both level left to right, and more and aft. Then by resting the hinge pin on this jig we could get an accurate balance. I am glad we took time to set up this jig as the results were more repeatable and best of all, one of the elevators is well within balance. The other one needs a bit of work, but is close. Good news is, I am under the max allowed weights for both and if need be we can simply add a few ounces on the right elevator outboard balance weight. But we will try to get it in balance by sanding first. I do know that there is almost zero micro and primer on the elevators, so I am not sure how much we will be able to change the balance by sanding, but it is worth a try before adding weight.

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Well Balanced elevator.

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Needs a bit of work. Of course, the plans have you balance the elevator before any finishing, but the plans also say that the elevator must balance trailing edge up. We checked for curiosity, and It took 2 ounces to balance it, which is well under the allowed 5 ounces allowed.

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Nate also finished painting the roll over structure.

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More tomorrow. Hopefully we get the aileron repair done so that we can do the finishing on it. We will also do some elevator sanding to see if we need to add lead to the balance weight. Maybe we will get past this balancing act and move forward.

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One thought on “Lacking Balance”

  1. Two points:

    – Use 2-ply BID over the rod – more concentrated weight, more structure needed (and it will be helpful weight), feather/stagger on the bottom. – Be sure you (at some point) add the pitch trim collar/bellcrank over the inboard left elevator hinge insert. Even if you are not using the plans pitch trim spring setup, you MUST install the collar with the proper number of rivets as it is what transfers the torsional loads from the stick to the elevator and vice-versa. Otherwise, only the thin partial wall of the tube is carrying the load and will crack/fail over time. Just be mindful that the rivets don’t interfere with the hinge pin after being squeezed.

    -James

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