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Check those screws on c/b rudders

wrongway john

Well Known Member
My 6 has a RV-8 tail, and during the condition inspection today, we came across this:

2n1i6wz.jpg


The two screws are loose, won?t tighten nor will they come out. My A&P wrote Van?s which will send him rudder drawings. The front screw has another little hole beside it; not sure if it has a purpose or somebody did a screw up. Had any of these screws come down another few thousands on an inch, it could have easily caught on the vertical stabilizer. This has got bad news written all over it. Looks like I?ll have to drill out some rivets to get to it.

I?ll be making this a part of my pre-flight inspections from here on out.

Anyone else experience this?
 
One idea to get to the bolts on the other side of the weight is to cut a hole through the end of the fiberglass rudder tip. If you use one of those vibrating cutters, it goes real fast. I know. The tip is easy to repair. You would have to decide if it is easier drill out the rivets or go through the end of the rudder tip.
 
Those bolts are held with locknuts and since there is no relative movement in parts, I would imagine a mistake during building. One possibility is that the weight was not fully set in its place and was held up by the rivets on the side which you would typically need to shave a bit off the weight to get it to fit nicely. This is specially that both bolts are lose.

You could drill a hole on top of the wing tip for the size of a 3/8 socket and just tighten it. Then glass over the tip and repaint, shouldn?t be that difficult but a very good catch.

Good luck.
 
I like these suggestions, beats drilling out a bunch of rivets. Normally, when I do a pre-flight the rudder is straight with the VS, so this is hidden fairly good. Just caught this, because the rudder was turned, so got a good look at the screws. Kind of scary to think what one of those screws could have done to ruin my day.
 
Yup... drill a hole from the top, use a nut driver so you don't loose a socket. Phillips on the bottom side and lock her down. You can re-glass, cap or plug the holes it the top. :)
 
everyone....add to pre-flight checklist!

........Normally, when I do a pre-flight the rudder is straight with the VS, so this is hidden fairly good. ..........

not a criticism of your preflight ... I am lucky that my builder had already put this on his pre-flight, or I'd likely overlook this also.

Part of most walk-arounds is to; remove all control locks, move the control surfaces to their full travel, look at all gaps and hinges, listen for chafing, and of course, verify all weights, cables, pushrods, hinges, fasteners are secure and clear.
THe downside of an -A model is that it's not easy to grab the rudder tip and check for security, but if you want to be thorough, go grab the ladder from the Cessna beside you, and get up and look things over. Don't be surprised if the top of the VS is full of bird ****!
 
When I install weights, I use plenty of proseal to lock everything in place.

The lead is soft and as someone eluded to above will take a set over time, if the bolts rotate but don't appear "loose" it may be ok, if unsure, then get to the nut and snug em down.
 
Good catch - I'll check mine on the next walk around. Thankfully tip is screwed on.
Jim Sharkey
RV-6 (-8 Rudder)

My 6 has a RV-8 tail, and during the condition inspection today, we came across this:

2n1i6wz.jpg


The two screws are loose, won?t tighten nor will they come out. My A&P wrote Van?s which will send him rudder drawings. The front screw has another little hole beside it; not sure if it has a purpose or somebody did a screw up. Had any of these screws come down another few thousands on an inch, it could have easily caught on the vertical stabilizer. This has got bad news written all over it. Looks like I?ll have to drill out some rivets to get to it.

I?ll be making this a part of my pre-flight inspections from here on out.

Anyone else experience this?
 
Definitely, think I?m going to cut a circular hole in the fiberglass in the flat end portion that will generally be hidden. And now that I know they have nuts on the other end, I?ll quit calling it screws. Just looked like that to me at first.

Walt, that proseal sounds like a good idea. I unlocked my tailwheel to where I could easily move the rudder back and forth swiftly, and don't hear anything rattling inside. Once I get a good look inside, if I can get around the small opening, once I have tightened the bolts, I might use some of that or possibly JB Weld to help lock things down a bit.
 
Wrongway to cut the hole

You need to cut a circular hole, big enought for a socket or nut driver, directly and vertically above the machine screw. I think a unibit might work (it will dull the bit) but should give you the cleanest hole.
Good luck.
Terry, CFI
RV9A N323TP
 
I was hoping to get to it through the flat end on the front of the rudder to get to it. It’s got room for about a 1½” hole which I hope I could get a wrench in there for both nuts. I would hate to go from up top, which I guess means cutting two small holes big enough for the nut driver. I’m not going to do anything until I get the drawings, then I’ll have a little better idea of how I want to go about this. Thanks.
 
You might find the nuts counter-sunk deep enough into the lead weight that you cannot get an end-wrench on them coming in from a hole in the front portion of the fiberglass.

However you cut the fiberglass to get to them, I'd put some LocTite on the threads before tightening it down. Since they came loose, I'm wondering if maybe the nuts used were not locknuts, but plain nuts. Even with locknuts, I'd add LocTite to them anyway.... and probably use the red formula to ensure it ain't gonna come loose again.
 
You might find the nuts counter-sunk deep enough into the lead weight that you cannot get an end-wrench on them coming in from a hole in the front portion of the fiberglass.

Van?s immediately sent me a drawing, and you?re right about them being countersunk, so I?ll come in from the top with a nut driver as others suggested.

However you cut the fiberglass to get to them, I'd put some LocTite on the threads before tightening it down. Since they came loose, I'm wondering if maybe the nuts used were not locknuts, but plain nuts. Even with locknuts, I'd add LocTite to them anyway.... and probably use the red formula to ensure it ain't gonna come loose again.

Makes sense to me, and am going to do just that. I?m curious now as to what kind of nuts they used myself, will find out soon.
 
Makes sense to me, and am going to do just that. I?m curious now as to what kind of nuts they used myself, will find out soon.

Try to view the counter weight on the sides and make sure it is not being held up by the rivets end. One other possibility is that the nut was bottomed out. As I recall, I had to put two washers to make sure my nut is not bottoming out.
 
this is fun

After studying the drawings Van?s sent me, I decided to go ahead on the end after all. I used a 1 3/8th hole saw. It gave me plenty of room to see everything, and get either a small socket or box end in there with no problem. Both work quite well, only really need one or the other.
25un0j6.jpg


I didn?t see any problems on what could have caused these two nuts to back out. They were the locknuts that were supposed to be on them. Both had the washers. I tightened them all back down at first, to see if they would, and they did. Then took the bolts, washers and nuts all out to look at it some more. I used strong hand pressure to see if the locknut could go on that way, but it was still tight, and wouldn?t go any further after a few turns indicating to me the locknuts are still just fine. This 8 rudder is only 4 years old, and probably doesn?t have 200 hours on it. As another suggested, I did check to see if the lead weight was resting on any rivet. It wasn?t, it was nice and flat. The nuts still had threads to spare on the bolts, so they weren't bottomed out.

Neal, what red stuff are you referring too? The red silicone I have in the pic? Should I cover the top of the threads and nut with it after I use some Loctite or equivalent on threads too?

Here are the tools I used along with a few other things.
21o1tp3.jpg


If you?re wondering what the magnets are for, well, here goes. :D The nut to the back bolt fell off, and there was a very small opening at the rear where it fell down further into the rudder. It went completely out of sight. I located it about 6? further down into the rudder before it caught on the stiffener. I knew it was there, because I would take my magnet, and it would rattle around. Since the plane is aluminum and non-magnetic, and the nut was magnetic, I was only picking up on it.

I took the long claw pick that has magnets on it (Harbor Freight, best $2.00 I ever spent) and placed it horizontally as far as it would go in the opening I cut and let it rest there. I then took the machinists magnetic base and put it between my plane and a piece of paper to keep from scratching my paint. I slowly wriggled it back up to the top, hoping I could get it to stick to the other magnet pick up. The magnetic base has a on and off switch which I turned off when at top hoping it would catch on the other magnet. I didn?t hear anything drop back down. Went to gently pull the magnetic claw pick out, and sure enough the nut was on there! I got it out the first try! Man that was fun! I rarely get that lucky.

Even if I wasn?t able to retrieve it with the magnet, it was still loose in there, and I could have took off the three nuts to the rudder, then undo the tail wheel clips, pulled the whole thing out, turned it upside down, and shake it out that way.

I?m showing the other 150 lb magnet from Harbor Freight in the pic to show you that one that didn?t work. The force was too spread out to lift the nut, but the other one shown you can also get at HF works great, and has plenty of lifting power along with a on and off switch which I think helps keep your object from being lost again, by gently releasing the magnetic force.

Now just wondering if I should re-use the same nuts, or go with two new locknuts? For extra insurance I?m going to use something like threadlock no 71 which I already have, unless others advise against it and instead think I should go with Loctite. I?d use it if I could find it locally. I?ll just have to order through mail and wait a week or so to get it.

I hope this helps others, and do your Vanhead friends a favor, and remind them to check those two bolts each time on every preflight. Nobody will ever have to remind me.
 
My 6 has a RV-8 tail, and during the condition inspection today, we came across this:

2n1i6wz.jpg


The two screws are loose, won?t tighten nor will they come out. My A&P wrote Van?s which will send him rudder drawings. The front screw has another little hole beside it; not sure if it has a purpose or somebody did a screw up. Had any of these screws come down another few thousands on an inch, it could have easily caught on the vertical stabilizer. This has got bad news written all over it. Looks like I?ll have to drill out some rivets to get to it.

I?ll be making this a part of my pre-flight inspections from here on out.

Anyone else experience this?

Yeah, I had a mechanic point to one of these screws backing out on my 1st RV 8. ( I wasn't a builder) SHAZBUTT!!:eek: I now regularly pre-flight these screws
 
Part of most walk-arounds is to; remove all control locks, move the control surfaces to their full travel, look at all gaps and hinges, listen for chafing, and of course, verify all weights, cables, pushrods, hinges, fasteners are secure and clear.
THe downside of an -A model is that it's not easy to grab the rudder tip and check for security, but if you want to be thorough, go grab the ladder from the Cessna beside you, and get up and look things over. Don't be surprised if the top of the VS is full of bird ****!

Another good thing is to grab both sides of the elevator and check for differential movement. If any is detected, it most likely means your control horns-to-pushrod bolt is loose!
 
This thread had me heading out to the shop to stare at my rudder a bit; metal work done for a while but tips not on yet. Want to head this problem off before closing it up, but don't want to add the weight of a top plate on the lead. Was wondering... what about a single ply of fiberglass along the bottom of the counterweight to keep the screws in place... and some epoxy around the nuts and possibly the base of the weight to hopefully keep it from shifting and loosening... or will the malleability of the lead defeat all this? I'm thinking that if this is going to be a sealed area, it should be treated as non-serviceable, therefore sealing the screws won't be an issue. Just pondering here...
 
This is something that always concerned me about my RV-7 build. The RV-7 rudder has a metal skin covering the "box" that the counterweight sits in, and theres no easy way to get to those bolts to check their tightness during an inspection.

Here's what I am talking about:

PmsY965h.jpg


If I had to ever tighten those nuts, would it be OK to take the fiberglass fairing off, and then enlarge the holes (pink arrow) in the R-903 tip rib to fit a nut driver in there?

Or would you drill a hole in the forward side of the R-913 counterbalance skin to get a wrench in there and hope you could get it in the countersunk holes for the nuts?

Additionally, I am kind of in agreement with Martin. Might it be a good idea to do a "wrap" of thin fiberglass cloth around the screw heads and around the fiberglass tip? That would certainly help keep the screws from falling down and jamming the rudder. Even if the counterweight (on an RV-7 rudder like above) got completely loose, it would be trapped in its little metal box made by the skin and 912 and 903 ribs.
 
Last edited:
This is something that always concerned me about my RV-7 build. The RV-7 rudder has a metal skin covering the "box" that the counterweight sits in, and theres no easy way to get to those bolts to check their tightness during an inspection.

Here's what I am talking about:

If I had to ever tighten those nuts, would it be OK to take the fiberglass fairing off, and then enlarge the holes (pink arrow) in the R-903 tip rib to fit a nut driver in there?

Or would you drill a hole in the forward side of the R-913 counterbalance skin to get a wrench in there and hope you could get it in the countersunk holes for the nuts?

Additionally, I am kind of in agreement with Martin. Might it be a good idea to do a "wrap" of thin fiberglass cloth around the screw heads and around the fiberglass tip? That would certainly help keep the screws from falling down and jamming the rudder. Even if the counterweight (on an RV-7 rudder like above) got completely loose, it would be trapped in its little metal box made by the skin and 912 and 903 ribs.
This is a little more complicated than it might need to be. Two issues, coming loose, and checking it after the part is constructed.

1. Coming loose. The lead is not real solid due to they way it has been cast. It also is softer than, say, a lead balance weight. I bought some extra weights for another purpose and tested it's ability to accept standard torque. It wouldn't , the lead would embed even a standard washer. If your weight is like this there is no way it will stay tight in service. I machined an aluminum washer/spacer with a diameter of the counter bore and retested the torque acceptance to 30 in lb. It was nice and hard.
2. Retorqing. A couple of nut plates attached to a strip of aluminum in place of the nuts will allow a one sided check/retorque of the nuts. This is a standard design now for the RV14. But they still have not addressed the spacer issue, so take note.

Just because I was going belt and suspenders, I bedded my weight in proseal per recommendation from Walt. Likely overkill with good torque retention.
 
Reading this thread as the screws in my RV-8 rudder free spin. They don't appear to be getting any looser, but I check them on every preflight now.

Question I had; why is everyone going in through the front of the fairing, vice drilling out the rivets?

If it's a matter of having bare metal replacement rivets on a painted airplane, I don't mind that, as it would match the skybolt fasteners and elevator tips.

Is it more difficult to drill rivets out than to cut a big hole in the rudder tip?

What am I missing?
 
I had been watching those counterweight screws continue to loosen on my 2004 -7 with 1400 hrs. Tried multiple ways to affix the screws but worried they might loosen enough to scrape the top of the vertical stab. Ended up drilling out the painted rivets on the rudder tip and found the lead had distorted under the washers of the nylock nuts. Lead creeps over the years. Vibration, temp changes etc. so, I made an aluminum plate with two nut plates, flipped over the lead block and tighterd it up. No movement at all in the last year. Suppose I could have shaved off a bit of lead to compensate for the weight of the aluminum plate and nut plates. But I didn’t. Used flush pop rivets for the rudder tip and touched up the rivet heads with a modeling paintbrush. I am happy with it and it only took part so a rainy afternoon to fix what had been a concern for a whole year.
 
Proseal was not mentioned in the manual but I like the idea! My rudder is complete but there are other weights left to install. Thank you for the tip.

When I install weights, I use plenty of proseal to lock everything in place.

The lead is soft and as someone eluded to above will take a set over time, if the bolts rotate but don't appear "loose" it may be ok, if unsure, then get to the nut and snug em down.
 
Just found this same issue

I have a -6 with an 8 tail on it, and just found these same screws (bolts) loose on my rudder as well. Haven't worked on it yet, but still planning on going in through the front flat part of the rudder as it seems that it will be an easier repair than going in through the top.

Have people had success getting to the lock nuts going in this way?

Thanks in advance for the help, I didn't build my plane so I'm trying to make sure we have all the information before we start putting holes in the plane...
 
Fixed it

After looking at some drawings and consulting some of the builders, I went for it and drilled a hole in the fiberglass on the front flat part of the rudder. About 1 1/2 inch up from the bottom and in the center. Was able to get a box wrench in there (after a little grinding on the wrench) and get around both of the lock nuts! Thankfully an uneventful drilling into the plane, which was more than a little nerve wracking...

Placed a flush plastic plug in the hole so it can be accessed again in the future if needed.

Picture included in the hope that it will help someone that finds this issue in the future.
 

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