Correcting Rolling Tendency

[Scott99]

I'm a new OneX flyer, started flying a purchased aircraft last week.

The plane his a slight left rolling tendency I'd like to try to correct...anyone have suggestions / information on how they've overcome such a situation?

[XenosN42]

Hi Scott,

You can attach a trim tab similar to ONX-B04-07 to the underside of the right aileron to correct a left turn tendency. Have fun with your OneX!

[GraemeSmith]

For ANY plane - I'd check it is in rig before adding tabs.

I was pretty sure the Sonex I purchased was rolling left - but it was just my sad sack sitting left side. Put in a passenger and she was level.

Now I realize you are talking Onex - but I'd check the rig before adding a tab.

[Rynoth]

For Sonex/Waiex, you can trim the roll by adjusting the flap pushrod-ends. You just extend the flaps for access to the rod-end, disconnect it/loosen the stop nut and make some turns (while ensuring you still have adequate thread engagement via the witness hole.) I have done a fair bit of this over my first several flights due to being left-wing heavy, eventually going 4 full turns down on the left and 3 turns up on the right. Apparently my plane is a bit crooked. I did re-measure the angle of incidence and found that the left wing was about 1/16" higher at the aft spar than the left. Tweaking the flaps appear to have compensated well, as resetting the angle of incidence would be a pretty big project.

Can the same adjustment (flap pushrod ends) be done in a Onex?

[Scott99]

Hi Scott,

You can attach a trim tab similar to ONX-B04-07 to the underside of the right aileron to correct a left turn tendency. Have fun with your OneX!

Thanks Michael...I will look in to that. I was hoping to be able to make an adjustment to either the left aileron or left flap to work it out rather than having to attach anything, but will keep that in mind...

Really appreciate the input.

[Scott99]

For Sonex/Waiex, you can trim the roll by adjusting the flap pushrod-ends. You just extend the flaps for access to the rod-end, disconnect it/loosen the stop nut and make some turns (while ensuring you still have adequate thread engagement via the witness hole.) I have done a fair bit of this over my first several flights due to being left-wing heavy, eventually going 4 full turns down on the left and 3 turns up on the right. Apparently my plane is a bit crooked. I did re-measure the angle of incidence and found that the left wing was about 1/16" higher at the aft spar than the left. Tweaking the flaps appear to have compensated well, as resetting the angle of incidence would be a pretty big project.

Can the same adjustment (flap pushrod ends) be done in a Onex?

Hey Ryan...

Thanks! This is kinda what I was looking for...just wasn't sure it was the "right" thing to do or not. The flap systems seem to be similar on all the Sonex aircraft, so my assumption is I should be able to make this type of adjustment. I'll take a look when I head to the airport Friday and see.

Thanks for the suggestion...much appreciated!

Scott

[Onex107]

Check to see if the ailerons line up with both wing tips with the stick centered. I found one drooping a little. The Onex should be square as assembled.

[Rynoth]

Check to see if the ailerons line up with both wing tips with the stick centered. I found one drooping a little. The Onex should be square as assembled.

While this is ideal, it wouldn't affect roll tendency as the stick will still self-center from the aerodynamic forces. Roll tendency could be a result of many factors (CG, wing incidence, prop rotation, flaps, yaw, trim tabs, difference in built shapes of wings/control surfaces, etc) but the aileron rigging is unlikely to cause a hands-off roll tendency.

Just to add an unrelated anecdote, we have a Pilatus PC-12 that started to have a wicked left-roll tendency any time the flaps were extended. Our certified shop spent hours trying to find the reason, right down to laser-measuring the airframe to see if it had been twisted somehow. It ended up being anti-chafe tape on the top of the flaps that had lost some of it's adhesion, such that it would lift up on the forward seam in airflow along the entire length of the flap. It was basically stalling out the left flap when they were extended.

[Rynoth]

Thanks! This is kinda what I was looking for...just wasn't sure it was the "right" thing to do or not. The flap systems seem to be similar on all the Sonex aircraft, so my assumption is I should be able to make this type of adjustment. I'll take a look when I head to the airport Friday and see.

I'm not sure where it is called for in the plans/manual, but for Sonex/Waiex there are fairings to be added to the flaps AFTER the flaps have been tweaked to the desired deflection when fully retracted. I (and I'm sure others) can attest to the fact that tweaking the flap push-rods works great to trim out roll tendencies.

[Onex107]

Check to see if the ailerons line up with both wing tips with the stick centered. I found one drooping a little. The Onex should be square as assembled.

That's true but start with the simple things first. Remember, the ailerons on a Onex are twice as long as on a Sonex. And the flaps are half the size.

While this is ideal, it wouldn't affect roll tendency as the stick will still self-center from the aerodynamic forces. Roll tendency could be a result of many factors (CG, wing incidence, prop rotation, flaps, yaw, trim tabs, difference in built shapes of wings/control surfaces, etc) but the aileron rigging is unlikely to cause a hands-off roll tendency.

Just to add an unrelated anecdote, we have a Pilatus PC-12 that started to have a wicked left-roll tendency any time the flaps were extended. Our certified shop spent hours trying to find the reason, right down to laser-measuring the airframe to see if it had been twisted somehow. It ended up being anti-chafe tape on the top of the flaps that had lost some of it's adhesion, such that it would lift up on the forward seam in airflow along the entire length of the flap. It was basically stalling out the left flap when they were extended.