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Uncommanded yaw issues

M

MConner

Well Known Member
I just bought an RV-10 and on the ferry home I notice that occasionally there is a noticeable uncommanded yaw. I have looked everything over and see nothing out of the ordinary. The only thing I can guess is that one or both of the landing gear fairings are deforming causing the yaw. Has anyone experienced this and what did you do ?

Mark
AA-5B for sale
RV-10
 
Ok the plane fly’s with a small amount of left ball on climb out. Once in cruise, if I step on the left ball, it seemed to shift to a lot of right ball. Moreover the fast speeds seemed to bring this on more. In a high speed descent, I suddenly yawed 15 degrees and since the AP was on, the plane banked 10 degrees right to hold heading. I was in a big slip. This always seems to go away when I slow for landing and the nosewheel is not cocked at touchdown and no shimmey. I wonder if the nosewheel is cocked in the pictures because the plane is flying in a slip or if the nosewheel is causing the problem.
 
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No expert but ---

Your last post scares me. Don't want to alarm you but if that happened to me, I'd ground the airplane and check everything in the controls systems and in particular, the mounting of the VS, HS, and rudder. Use the construction manual for reference. Don't overlook what may be happening to the control system mounts inside of the fuselage. Also, look and and correct any misalignment of the ailerons.

In short, something is causing this yaw problem. Possible that something is coming loose or rubbing or binding something. Don't fly again until you are pretty certain that you have found the problem.

It's a long shot but have you checked the engine mounts and associated mounting assemblies? I think that I'd give the airplane the equivalent of a yearly Condition Inspection with someone who has RV experience to help you.

Please don't take my alarm and suggestions as criticism - I'm scared for you and think that the cause can be found before further flight. Best to you.
 
The most likely cause has been explained.
The simplest way to find out if it is the cause in your case would be to check and see if the nose wheel breakout force is adjusted to the specified value.

If it is, then you will have to keep investigating.

If it is not, you can readjust it and then post whether those that responded where correct.
 
Just to add to the general consensus...

In my 14, at about 100 hours, I started to notice that I needed to hold right rudder just a tad to keep the ball centered in cruise. At the same time, when landing, I got a bit of nose wheel shimmy when the nose wheel touched down.

Tim Olson had posted about this happening on his aircraft, and it being caused by the initial breakout force lessening. I checked and found the breakout force had dropped to around 13 pounds. I tightened it back up and all was fine again. I've put another 50 hours on since and all remains well.
 
Mark,

I had the same breakout force issue like Brian on that video. The nosewheel doesn't return to center and it's causing this yaw. It usually stays like that throughout the whole flight. Mine did anyway.

Here's how you can check Pull off the front wheel fairing, jack up the nose gear with a scissors jack, make a safety wire loop around the axle nut washer and attach a fish scale to the loop. The breakout force should be 26lbs. If it's loose tighten the nut under the belleville washers and then you may need to drill a new hole for the cotter pin.
Btw, to save you some time, once you split off the front of the wheel fairing, remove the towbar attach bolts and then the aft part of the fairing will slide off towards the back.

If the breakout force is not your problem, you might want to call up someone who is knowledgeable about RV-10s. Looks like Jesse Saint is pretty close to you.

Lenny
 
Change washers

Lenny Iszak said:
Mark,

I had the same breakout force issue like Brian on that video. The nosewheel doesn't return to center and it's causing this yaw. It usually stays like that throughout the whole flight. Mine did anyway.

Here's how you can check Pull off the front wheel fairing, jack up the nose gear with a scissors jack, make a safety wire loop around the axle nut washer and attach a fish scale to the loop. The breakout force should be 26lbs. If it's loose tighten the nut under the belleville washers and then you may need to drill a new hole for the cotter pin.
Btw, to save you some time, once you split off the front of the wheel fairing, remove the towbar attach bolts and then the aft part of the fairing will slide off towards the back.

If the breakout force is not your problem, you might want to call up someone who is knowledgeable about RV-10s. Looks like Jesse Saint is pretty close to you.

Lenny
Click to expand...

Rather than drilling a new hole, select a different thickness plain washer (the AN960-2010) under the big nut or sand one down a bit.

A 0.005 inch difference in washer thickness will move the nut and cotter pin hole 1/12 of a turn.
 
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Mark, feel free to fly up to X35 and I can help check and set the right breakout force. That is most likely the problem. If it is really loose you will end up breaking your nose wheelpant before long. It?s an easy thing to check (free) and fairly easy to fix (very cheap). Finding out what is causing your problem (priceless).
 
Jesse,
I appreciate your offer to help. I would love to visit you sometime soon but I have owned Grumman?s for over 15 years and understand breakout pressure and belville washers. I will take you guys word for the probable solution but it must be part of the pressure recovery wheel pants that causes this as it has never been reported in the Grumman owners group. I will jack it tomorrow and put the fish scale on it and report back.

Mark
 
A ratchet strap between the tail tie down and a tie down point on the ramp works. Some people use a heavy weight...

-Dave-
N102FM
 
Ok the break away was at 7 pounds, very low. I am surprised it didn?t shimmy. 3/4 of a turn on the castle nut while working the fork back and forth finally got me to mid 20?s.

I found some slop in the strut in the shock absorbing direction. Will troubleshoot it tomorrow.
 
MConner said:
I found some slop in the strut in the shock absorbing direction. Will troubleshoot it tomorrow.
Click to expand...

This is covered in the plans. As the shock absorbing ?donut? takes a set, you need to add a large washer(s) to take up the slack. While you?re there, check that the SB has been done.
 
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