Listen to the sounds your airplane makes....it may save your butt.

[joeboisselle]

Come to think of it, mine squeaks under the rear passenger floor too.

[msnook100]

...specifically what was the "something" that the torque tube was binding against? (A pic would be cool!) And on another level: Why was it binding on THIS particular RV-4 and not on any of the others? How are you going to prevent the NEW torque tube from binding on the same thing? --Mike

[Walt]

Originally Posted by msnook100

...specifically what was the "something" that the torque tube was binding against? (A pic would be cool!) And on another level: Why was it binding on THIS particular RV-4 and not on any of the others? How are you going to prevent the NEW torque tube from binding on the same thing? --Mike

It was one of the thin (.020) horizontal floor stiffeners, a small relief contour ground out of the stiffener cured the interference. I've had to do this before on both elevator and ailerons when the torque tubes chafe structure, but this particular one even surprised me on how deep it had gone from what seemed like a "minor" scraping sound. The situation was likely worse when someone was sitting in the back seat due to downward deflection of the floor.

[GLPalinkas]

I'll be checking those tubes, even though I just finished a condition inspection. Nice catch Walt.

[Grumpy-Hodge]

When I was a student pilot flying a C-150 at the time, I was performing final control check before entering the runway and elected to return to the ramp. I felt a slight resistive force when turning the yoke full right. It felt like a slight detent kind of action if you can imagine. I returned the keys to the keybox and put a "Grounded" tag on the same key. I called the maintenance head and told him I had grounded the airplane and for what cause. He wasn't too please with me because the weekend was coming up and weather was perfect for flying - read the airplane was fully booked. Well, I spoiled plans for a bunch of students.

Jump to the conclusion...The aileron piano hinge wire had somehow failed - I never saw it and don't know the details. Maintenance man called me back later in the day and said that I had made the right decision. He was very concerned that had flight(s) continued, an aileron jam near a full throw position could have occurred. You don't survive those unless all of the ration of altitude for the day is above you while you are still safely on the ground.

Be sensitive to something unusual in the flight controls.

[eisnerrv4]

Thanks Walt for posting this.

I'll definitely keep this one in mind if I hear sounds that I'm not sure of.

This is what I love about VansAirforce.net

Thanks Doug.

[jdeas]

Originally Posted by Walt

It was one of the thin (.020) horizontal floor stiffeners, a small relief contour ground out of the stiffener cured the interference. I've had to do this before on both elevator and ailerons when the torque tubes chafe structure

Not specific to RV4. My 7 had the same problem. Minor scraping noise with elevator movement in one spot was noticed by my designated co-inspector
during the condition inspection. Nothing needed to be replaced but a relief had to be cut in structure and the tube/struc cleaned up from where it was rubbing.

[JanRV6UK]

Originally Posted by jdeas

Not specific to RV4. My 7 had the same problem. Minor scraping noise with elevator movement in one spot was noticed by my designated co-inspector
during the condition inspection. Nothing needed to be replaced but a relief had to be cut in structure and the tube/struc cleaned up from where it was rubbing.

Hmm I wonder how many RV6 have the same pushrod scraping the top of the cut out in F-605 and hitting the underside of the flap cover .....

[RV7A Flyer]

Same here on my -7A...elevator pushrod rubbing on the cutout in the rear baggage bulkhead (whatever part number that is). Found during construction, relieved the hole with sandpaper, cleaned it up, and then even put some UHMW tape on the pushrod in that location just in case it ever rubbed again (under G forces?), checked each annual.

I'd guess a *lot* of planes have a similar issue...hopefully, they're caught during construction or A/W inspection.

[airguy]

Prepping right now for my first condition inspection just before Mel shows up for my AI, and yesterday I heard that same type of minor rub coming from my right aileron. Haven't had time to investigate it yet but I'm sure I'll be pulling that apart to get to whatever it is...