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Rudder cable bulkhead hole

B

beberle

Active Member
I'm having a problem with rudder travel. Right rudder is fine, the clevis just hits the snap bushing in the left bulkhead. After much research, I'll be adding the split tubing to smooth that out.

However, Left rudder travel seems to be limited either by rudder cable length or because the right bulkhead hole is too low. The clevis body doesn't move far enough aft to hit the snap bushing because of cable tension.

Any thoughts?
8263351807_a62eb8375f_m.jpg
 
Have you set your rudder stops yet? With the rudder stops set to recommended travel, this might be a non-issue. I know this is very close and I wondered about it when I built my 7A. Never had a problem once completed, though.

Roberta
 
I just purchased my 6-A two months ago. The rudder will come close or hit the right stop, but the left won't because of the cable bend at the 1st bulkhead. I'll have to measure the rudder deflection left and right to see where I'm at.
 
If your kit was purchased around mid April 1998, Van's shipped the wrong cables to a few customers. The correct cable number is F-6121.

Drawing #40 shows them to be 161" eye to eye.
 
Same problem

I recently connected the rudder cables on my 9A for the first time and found the same issue...good throw to the right but less than 1/2 deflection required on left pedal due to cable angle between pedal and co-pilot 1st bulkhead, exactly like your picture.

Appears my problem is that I positioned the pedals for comfort (tops leaning slightly forward) instead of vertical. My plan is to lengthen the rudder cable links (F-6119) about 1" to get the bottom edge of the pedals further forward from the 1st bulkhead. Haven't tried it yet. Downside is potential to ride the brakes on the ground or having to add an aftermarket extension on pedal bottoms.

Good luck!
 
AF_Alan said:
My plan is to lengthen the rudder cable links (F-6119) about 1" to get the bottom edge of the pedals further forward from the 1st bulkhead. Haven't tried it yet. Downside is potential to ride the brakes on the ground or having to add an aftermarket extension on pedal bottoms.
Click to expand...
Alan,
Unfortunately, changing the length of the links will probably not address your issue, at least not fully. It's largely a function of how long the cables are. One thing that I found helped was to insert the bushing from aft side of the bulkhead. Though counterintuitive, it better guides the clevis toward the hole in the bulkhead. This topic has been addressed a number of times in the past, so if you search a bit in the archives you should find some more to mull over. Good luck.
 
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My rudder cable clevises were knocking the snap bushings out too...then I inserted them from the front and all was well.

Jim Bower
St. Louis, MO
RV-6A N143DJ
Flying
 
This is a -6x correct?

There was a change in hole location on the vertical web (F-602) nearest the rudder pedals when Van changed from the floor mounted pedals to the overhead hanging ones.

The hole was changed to be 7 inches above top surface of the lower longeron.

Rev R6 on sheet 25

Do you have the lower old hole locations?
 
Your pedals may be sitting aft a little far

What makes me think so is the higher angle from the Clevis to the snap bushing and the shortness of the link. Az_gila has a point to check out first. Setting pedals is such a personal thing. The previous owner may have had short legs, or wanted the pedal bottoms canted rearwards more for the neutral position. The further forward the rudder pedal bars are located and drilled through the longerons and the further towards vertical the pedals hang, the lower that angle is. For peace of mind, why don't you clamp the rudder in neutral and disconnect the two links and see what it looks like with the rudder pedals in a nearly vertical resting position (maybe canted aft just a little). You may end up making new links, each side being a different length.
See this link for just one example.....
http://www.rivetbangers.com/forums/viewtopic.php?t=3933&start=0&postdays=0&postorder=asc&highlight=
 
beberle said:
I'm having a problem with rudder travel. Right rudder is fine, the clevis just hits the snap bushing in the left bulkhead. After much research, I'll be adding the split tubing to smooth that out.

However, Left rudder travel seems to be limited either by rudder cable length or because the right bulkhead hole is too low. The clevis body doesn't move far enough aft to hit the snap bushing because of cable tension.

Any thoughts?
8263351807_a62eb8375f_m.jpg
Click to expand...

I had exactly the same problem with my 93' RV6. The rudder cables clevis would hit the snap bushing before reaching full travel. It was the same on both sides. The cable also did not have a straight pull just like your pic but probably not as bad.
To fix this I elongated the hole in the bulkhead so I got a straight pull for the cable and then made a "U" shaped stand off from .032 and riveted this to the rear side of the bulkhead. It had the hole in it for the snap bushing. Doing this placed the snap bushing further rearward and so I got both a straight pull for the cables and no fouling of the clevis end to the snap bushing.
I originally thought about adding the split tubing as you suggest but that did not solve the cable being deflected as shown in your pic. I am sure if left like that it will wear through the snap bushing and you will have cable wearing on bulkhead in no time.
A written description is always harder to understand than a picture so I will take some for you and post here tomorrow. It was an easy fix. :)
 
Thanks to all of the input, I have a baseline to start from. 1st, the top of the hole measures 7" from the lower longeron. Also, rudder deflection to the left is 31/8" from the elevator. Nowhere near 11/8"! The top of the pedals appear to be mounted in the forward-most set of holes. The pedals have what looks like a 10degree cant when centered.
Seems like I have two options. I can lengthen both attach links and set the pedals to vertical and see how that helps or lengthen the former hole like you suggested airtractor. I'll wait for your picks before I make a choice.

Thanks for the help gents!
 
Thr right rudder pedals are mounted on the fwd cross bar. When the right pedal is allowed to move this far rearward, the tab that the top of the master cylinder bolts to, will hit the left rudder cross bar and stop at that point.

Making longer links will resolve this issue.
 
Here is a couple of pretty poor quality pics I took for you today on my phone to illustrate what I mean. I have seen those pass through holes slotted over an inch on more than one RV6. It is also a good idea to install the two screws that hold the cable to the pedal with the thread facing the fuselage skin. This stops your feet and shoe laces getting tangled in the cotter keys and breaking the tails of the cotter keys off. If I recall correctly this actually happened to an RV4 some time ago.:eek:


29zasrp.jpg
eirwom.jpg
 
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Some good suggestions by Airtractor8

Notice Airtractor8 link length. Probably at least double or triple the OP's picture. Might be due to where pedals were mounted. Suggest the OP clamp neutral rudder, disconnect links, zip tie cable to pedal hole. Start by loosely cinching the pilot zip tie until cable is snug and pedal is more vertical. Clamp the bottom of the pilots left and right pedal together, then put a zip tie through co pilot pedal and cable and cinch it lightly snug. Unclamp the rudder and pedals, excercise the pedals and see what that gives you. You can slowly cinch up each zip tie to try canting the pedals further aft. Stop when you've got it feeling right and no hang up and hopefully hitting rudder stops on each side. Measure the distance between cables and pedal mounting holes and make new links using that length. I'm just guessing your links will at least double in length. If that doesn't fix it, I'd do just what Airtractor8 did to get rid of the binding problem. Neat idea about reversing the cotter pin locations.
 
The fix point is on the back and not on the front!

Hello,

I have exactly the same problem and my buddy also. I studied it for a while. First I also thought that it has to do with the link's lenght. But I found out that this is wrong due to the following reason:

- The FIX point is in the rear, at the attachpoint at the rudder.

From there it is always the same lenght to the bulkhead with the bushing, regardless where the pedal's are.

The only fix would be: VANS make the cable 1/2" longer!

Or you order them by ACS.

Regards, Dominik
 
swisseagle said:
Hello,

I have exactly the same problem and my buddy also. I studied it for a while. First I also thought that it has to do with the link's lenght. But I found out that this is wrong due to the following reason:

- The FIX point is in the rear, at the attachpoint at the rudder.

From there it is always the same lenght to the bulkhead with the bushing, regardless where the pedal's are.

The only fix would be: VANS make the cable 1/2" longer!

Or you order them by ACS.

Regards, Dominik
Click to expand...

Thats true and I thought that as well at the time but they haven't done it yet!:rolleyes: Sometimes you have to work with what you have:D
 
beberle said:
I'm having a problem with rudder travel. Right rudder is fine, the clevis just hits the snap bushing in the left bulkhead. After much research, I'll be adding the split tubing to smooth that out.

However, Left rudder travel seems to be limited either by rudder cable length or because the right bulkhead hole is too low. The clevis body doesn't move far enough aft to hit the snap bushing because of cable tension.

Any thoughts?
8263351807_a62eb8375f_m.jpg
Click to expand...

Remember what the OP was saying........ left rudder travel is restricted. It's not a case of shorter or longer cables.
 
beberle said:
Thanks to all of the input, I have a baseline to start from. 1st, the top of the hole measures 7" from the lower longeron. Also, rudder deflection to the left is 31/8" from the elevator. Nowhere near 11/8"! The top of the pedals appear to be mounted in the forward-most set of holes. The pedals have what looks like a 10degree cant when centered.
Seems like I have two options. I can lengthen both attach links and set the pedals to vertical and see how that helps or lengthen the former hole like you suggested airtractor. I'll wait for your picks before I make a choice.

Thanks for the help gents!
Click to expand...

Brian, Did you check this.........
"The right rudder pedals are mounted on the fwd cross bar. When the right pedal is allowed to move this far rearward, the tab that the top of the master cylinder bolts to, will hit the left rudder cross bar and stop at that point. Making longer links will resolve this issue."
 
gasman said:
Remember what the OP was saying........ left rudder travel is restricted. It's not a case of shorter or longer cables.
Click to expand...

beberle said:
I'm having a problem with rudder travel. Right rudder is fine, the clevis just hits the snap bushing in the left bulkhead. After much research, I'll be adding the split tubing to smooth that out.

However, Left rudder travel seems to be limited either by rudder cable length or because the right bulkhead hole is too low. The clevis body doesn't move far enough aft to hit the snap bushing because of cable tension.

Any thoughts?
8263351807_a62eb8375f_m.jpg
Click to expand...

Seems to me the problem is two fold. Fixing the cable tension problem by moving the pedals forward as others have suggested will still leave you with the cable clevis hitting the bulkhead snap bushing at full right or left rudder. A longer cable would certainly fix that but is the more expensive option fore sure .
 
Reversing the bushing and inserting it from the front side will give another 1/2 inch or so clearance.
 
az_gila said:
Reversing the bushing and inserting it from the front side will give another 1/2 inch or so clearance.
Click to expand...

Maybe but when I tried that on mine it still hit the bushing(only just).
There is probably some variations with this. My kit was non pre-punched so was up to the builder to locate and drill that bulkhead. The later pre-punched kits may have it positioned slightly further aft?
 
I hope everyone had a Merry Christmas! I just had time to run out to the hangar today and do some more investigation. Thanks to those mentioning to check the brake mount to top crossbar clearance, the problem became quickly evident...
The right brake hose is being pinched between the upper brake mount and cross bar when the left pedal is deflected. Not good. It doesn't appear that the brake line is long enough to route over the cross bars, which would give the best clearance. I'll do a search to see if there are any topics on brake line routing.
8307434833_e634c2480b_m.jpg

thanks,
Brian
 
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Success! I re-ran the brake lines and extended the pedal-to-rudder cable links by 1/2". I also reversed the cable grommets for better clearance. I almost got stuck under the panel once, but all's well that ends well :D
8322211868_a04a75a869_m.jpg

8322210166_e297662943_m.jpg
 
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