Heavy wing? But not really…

[Bcone1381]

My goal with this post is to say that if the hinge alignment needs to be adjusted, I've got experience. My method might be useful if the hinge alignment change is more than what the washer procedure can fix. Drrilling new hinges is not a huge job.

Don't mis-interpret this post for a recommendation of how to proceed, or as troubleshooting advice. I echo the excellent advice to call Bob, and other professional advice. I'm not that....I'm just a builder who made an error and got it fixed.

I've done just about everything twice on my project. I mis-drilled my left flap hinges and I was not happy with surface alignment between it and the wing. It sat up too high. top surface proud to the top wing surface.

Filling old holes with weld and re-drilling the old hinges was a waste of time. I lost material thickness when I tried this.

I think I got new un-drilled hinges from Mark and drilled them to fit the existing holes in the spar. (I may have fabricated new ones on my own....not sure.)

Drilling those holes into the new hinges so they exactly matched the Spar Holes that were in the airleron/flap spar took some thinking for a non-fabricator like me. I ended up making a V-shaped scissor jig out of flat steel stock.....each of the two blade were 3" long with a bolt hole drilled in each end of both blades. A single bolt attaches the two blades to fashion a hinge so it looks like scissors. I adjusted the holes spacing of the blade ends to fit the old hinge holes, tighted up the hinge bolt so its solid, then moved the jig over to the new hinge and match drilled the new hinge holes to the jig with my adjustment needed to give a very precise and exact fit.

[AKKen07]

Update after the last set of adjustments: I have a better feel for the issue after all the discussion and some improvement has been made!
- At 140mph the plane wants to bank left but I hold the stick about1 1/2 inches right of center. The ailerons are deflected to a position that matches the stick.
- Releasing the stick, it moves to an equivalent position left of center. The ailerons match the stick again. The plane banks left, the nose yaws right.
- Slowing to 100 mph the required stick position is around 1/2-3/4" right of center, the stick moves to a matching position left of center when released.
- Slowing to 80 mph the required stick position is around 1/4"
- Below 70 mph the plane flies level hands off.
- I have to hold right rudder at all speeds, though not much at higher speeds. Left turns are coordinated with my feet on the floor.

Next adjustments to test:
- Swapping left and right skis/rigging to see if they might be imbalanced.
- Lowering the left flap a turn to test effect.
- Adding a trim tab to the ailerons

[Battson]

That sounds like a very common and easily-solved problem! Nice to hear some good news on this front.

[AZBearhawk272]

Good report.

I was not aware that skis were involved, That is good to wring that out. ( My guess is that is not the forcing function...... )

I am postulating that my move would be to.................. push down on the " Light Wing " Right.
Raising the right aileron a bit will present the high drag front of the aileron into the airstream, creating drag and reducing lift that will yaw the airplane right........... reducing need for rudder.
Your other data point is that freely turning left is coordinated........ This means the left aileron, on the downward going wing, is creating adequate drag from the protruding leading edge to create a left yaw. The right aileron as it moves down is not yet creating drag, it just looks like a little bit of camber change.

Adverse Yaw is yaw that comes from greater drag on the downward going aileron which makes more lift, which causes drag, causing the nose to yaw right while turning left.
You need less lift on the right and more drag at cruise.
Properly rigged you will have adverse yaw and it will be equal right or left turn.

Raising the right aileron will also lighten the aileron feel as the " reflex " will unload the ailerons.

Ok, one more data point.

What is the wings level condition at flaps notch 1 and or notch 2?
The flaps " float " on the cable when deflected and will equalize when the ball is centered.
If plane is still left wing low that confirms that most likely the starting point is raising the right aileron.

Hope that helps.

Kevin D.
#272 KCHD

[AKKen07]

Thanks Kevin, currently I haven't added flaps until pretty slow where the ailerons stay pretty well centered on their own. I will look closer at this on the next flight.
So for the next flight - one set of washers under the lower mounts for the right wing and swap skis/rigging. Maybe I'll leave the flaps alone for now.
I'll report back in a few days...Cheers!

[AZBearhawk272]

Might be inclined to just adjust the Right aileron push rod to be two turns longer initially. Keep it simple and easy to undo, If it improves then think about washer placement. Washers are very powerful and needed if pushrod runs out of adjustment.
Sounds like you are getting close.

Kevin

[SXCARO]

AKKen07, it sounds like you have different aileron hinge moments left and right, caused by build tolerances. This is easily fixed by adding a trim tab or wedge to the left aileron that is bent upwards or if it is a wedge it needs to be on the upper surface trailing edge. You will need to experiment with the length of it, or angle if it is a trim tab that can be bent. I would start with 12” length.
You can also add it to the right aileron, but bent down.
You may also need one for the rudder, but ski-rigging would have an effect on that.

[AKKen07]

Thanks for all the input! I did wind up adding washers and a trim tab to the right aileron and it now flies straight with right rudder. A tab has been installed in the rudder but not flight tested yet.