Piano hinges play

[Murray Parr]

Not sure if the videos show it well but I have a reasonable amount of play in the right aileron and also the right ruddervator. All other hinges have next to no play. Plane hasn't flown yet so wear wouldn't be a factor.

Does this seem normal?

aileron.zip

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ruddervator.zip

(1.28 MiB) Downloaded 104 times

[GraemeSmith]

I've had to rectify similar at 400 hours when the aileron bellcrank bearing in the wing started to wear and develop slop in the bearing - which also transmitted to the hinges.

If those are the "stock" roll formed hinges - then it looks like the "roll" has opened up some. A reason some folks use the forged hinges.

Couple of things I would look at. Is it a "uniform" opening and they could ALL be gently squeezed tight again. Or is it just some - and you might have a bit of an alignment issue?

If the slop is by the actuating arm where the bellcrank/pushrod are pushing on the end of the aileron - that needs resolving. You have introduced some flex on the axial line of the hinge pin. That will allow wear to accelerate.

In any event - that is "slop" in the control system before you even get in the air. As presented in the videos - at a Condition Inspection my AP would "fail" those hinges for being worn out......

[Murray Parr]

I've had to rectify similar at 400 hours when the aileron bellcrank bearing in the wing started to wear and develop slop in the bearing - which also transmitted to the hinges.

If those are the "stock" roll formed hinges - then it looks like the "roll" has opened up some. A reason some folks use the forged hinges.

Couple of things I would look at. Is it a "uniform" opening and they could ALL be gently squeezed tight again. Or is it just some - and you might have a bit of an alignment issue?

If the slop is by the actuating arm where the bellcrank/pushrod are pushing on the end of the aileron - that needs resolving. You have introduced some flex on the axial line of the hinge pin. That will allow wear to accelerate.

In any event - that is "slop" in the control system before you even get in the air. As presented in the videos - at a Condition Inspection my AP would "fail" those hinges for being worn out......

I should be able to squeeze them a bit tighter, I am really surprised they have this much play in them as I drilled and riveted them with the hinge halves together and upon assembly, the pins installed without much effort.

Can anyone comment on the forged ones as to how much better they are and where to source them?

[daleandee]

I should be able to squeeze them a bit tighter, I am really surprised they have this much play in them as I drilled and riveted them with the hinge halves together and upon assembly, the pins installed without much effort.

Can anyone comment on the forged ones as to how much better they are and where to source them?

Can you order a larger wire size for the piano hinge?

Dale
Corvair 3.0 / Tailwheel

[Bryan Cotton]

Can anyone comment on the forged ones as to how much better they are and where to source them?

From ACS:

MS20001P aluminum hinge is extruded. The closed hinge loops cannot be pulled apart. Furnished with hinge pin. Anodized finish.

I get 7 pages of various piano hinges when I search for that on my phone. Might be easier on a PC.

Seems like you should not need an extruded hinge. Maybe bad quality control?

I've not seen the video yet.

[13brv3]

I have seen slightly different sized pins, but I wouldn't expect that to be a problem if all the hinges were using the pins they came with. If the pins aren't difficult to remove, you might try swapping left to right to see if the problem moves with the pin. At the very least maybe measure the pin diameter.

[GraemeSmith]

Can you order a larger wire size for the piano hinge?
Dale
Corvair 3.0 / Tailwheel

Tried that. The next increment is quantitively a step up and is too big.

[Murray Parr]

Looks like it might be a quality control issue. I checked the remaining unused hinges I have and they have very similar amounts of play in them. I will experiment with those to see if I can improve them by squeezing the loops, if that helps I will do the same to the ones on the plane.

[Panther16]

You might want check a well stocked radio control aircraft hobby shop. They normally carry a supply of various diameters of uncut hinge pins.