Rudder Rigging

[kimble]

I have rudders and peddles that are not centering. Before I start rigging, I need to know the call distance between the peddles and the firewall. From past experience, it looks like someone has rigged the peddles too far aft, which creates a throw problem. Must have had a short pilot in the aircraft history.
Kimble

[N170BP]

Are the right rudder return springs hooked up / functioning?

I'd check that 1st.... (sorry for mentioning it if you
already did!).

[GAHorn]

I have rudders and peddles that are not centering. Before I start rigging, I need to know the call distance between the peddles and the firewall. From past experience, it looks like someone has rigged the peddles too far aft, which creates a throw problem. Must have had a short pilot in the aircraft history.
Kimble

The rudder pedals are only connected to each other thru the rudder bellcrank itself. In other words, the return springs are the only thing that pulls the pedal forward. Therefore you should first determine the springs are not broken or stretched, next confirm the cables and pulleys/brackets are not broken, damaged, or mis-routed, then confirm that full rudder deflection is available (check your owner's manual for degrees of rudder deflection). Adjust the rudder stops at the bellcrank for correct rudder deflection, then adjust turnbuckles (if any) to even out the rudder pedals. Lastly, make certain that even with full forward rudder pedal that the pedal's spring is still applying at least some tension upon the rudder.

[lowNslow]

Might check your tailwheel spring tensions are equal, these could cause uneven tension in the rudder system.

[kimble]

Problem cured. Inspected control system for integrity, blocked rudders together, jacked tail wheel up and rigged rudder to center. The rudder spring tension is adjusted by the firewall/pedal distance. At this point, if the tailwheel does not streamline, adjust the tail wheel spring tension.

Incidentally, the "T" portion of the control column was hitting the back of the DG and the elevator was exibiting too much back throw. Isn't it interesting what you find in these old aircraft.
Ralph

[spduffee]

I reinstalled the rudder cable guides today - actually not all too bad, even though everything is all buttoned up.
So, now I have two issues.
The cable ends that attach to the turnbuckle still graze the aft skin at the back of the guide hole. Can that be improved? Will this repeated grazing eventually crack the new skin at that point or wear it away? The old skin had an external doubler at the aft circular end of the guide hole...
Next, the rigging. In reading this older post from Kimble, I think I understand, which probably means I don't. Can anyone provide a step by step rudder rigging for dummies? Do the tailwheel sprigs have to be attached to properly rig the rudder? Mine are detached - I was focusing on the rudder and cables only. Do I have to reattach them, jack up the rump and rig it all completed?

Thank you,

Shawn

[Bruce Fenstermacher]

The tail wheel has nothing to do with the rudder rigging. It is easier to have the tail wheel control chains off while rigging if the tail wheel is on the ground. Doesn't matter if it's off.

[blueldr]

There seems to me to be a lot of questions about rigging from people that are not really supposed to be doing rigging on their airplanes.

[c170b53]

Yes and no but mostly yes but....
I'd like to think that owners will avail themselves of sufficient information to carry out their maintenance and know their limitations. Really doing most of the work themselves will likely make them better owners, better operators and make the endeavour affordable. The big but to all of this; regardless of the ability and qualifications, some procedures should always have a second look to reduce possible human errors.
I think sometimes we see new participants into aviation who have not established a "network" to facilitate their understanding of the processes involved in maintaining their planes. As an association we want to provide the positive first steps for those individuals and not turn them away.
Blueldr you likely have more worn out shoes than most and have been down some trails none of us have had a chance at

[Bruce Fenstermacher]

BL is right and Jim is right.

It is the delicate path we walk. Should we not share info because we fear those not qualified will try to perform the work themselves. Or do we share to help both qualified and unqualified to understand a process and hope the qualified has an easier time and shares the knowledge and those unqualified use the knowledge to understand what and or how qualified people should be helping them to maintaining their aircraft. I subscribe to the later.

[spduffee]

Well, I thought you all new me and my circumstances...I work closely with the A&P/IA, just footsteps away. I'm sure after 1-1/2 years of this stuff he's ready to see me go, but he is always available and inspects what I do in great detail. It's not like I'm "winging it". I am sure that even if I had a huge bankroll I would do everything the same way. I can't imagine owning an airplane without understanding it. This 170 has put me through the ringer, financially, emotionally, caused many a dispute between my wife and me, but what a learning experience! I'm also designing an airplane. I guess I have no business doing that either, since I don't have a degree from MIT in aeronautical engineering, but neither do/did several designers of successful homebuilt airplanes. If you don't know, you ask. You learn about it and you learn by doing it. I have seen a lot of questions on this forum that would make an FAA man cringe, but good for those who do ask. We're not owners of Cirrus' here...we're owners of low-tech, old planes that give the owners opportunities to learn many facets of airplane ownership, maintenance and design. So if anyone knows how to rig the rudder and can explain it, step by step, please do. When I am done, I will have it checked out, like everything else.....

Thanks,

Shawn

[Bruce Fenstermacher]

Shawn, many times it is hard to keep track of who you might be talking to day in and day out here, who is qualified and or who is working with someone qualified.

It is good to have BL cut through the cloud with a reality check comment every now and them. Read and head if it applies. Don't take offense if it doesn't.

[Bruce Fenstermacher]

Here is how I'd go about rigging the rudder.

Lift the tail wheel off the ground.

To simplify things while rigging the rudder and feeling for proper unrestricted movement I'd disconnect the tail wheel.

Make sure the rudder stops are adjusted to allow the rudder to move left and right to the max allowed and when done the rudder does not interfere with the elevator through full elevator travel with the rudder at both extremes.

With the cables disconnected each peddle should be pulled towards the fire wall by the springs. If they flop freely to the rear the return springs aren't working and need to be looked at. Move each pedal against the spring pressure checking for consistent pressure between each pedal. If one is stronger than the other look at the springs. Many have been replaced with home made units it might seem or maybe one is broke or stretched. (edited from original).

With the rudder centered adjust either control cable at the turn buckle so that the corresponding peddle was 6" from the firewall at the hinge of the peddle and T. Adjust the other turn buckle so the other peddle matches the first. Move the peddles full travel observing that there is no binding of the peddles and brake linkage, and in my case I look to be sure the brakes are not being energized at the extreme right pedal because I have had problems with this.

Reconnect the tail wheel.

Run the rudder through full travel to insure all is working unrestricted.

With the rudder at full deflection the tail wheel should brake out in free rotation (unlock) with a bit of pressure and a snap when moved in the same direction. If it doesn't your next maintenance should be on the tail wheel.

[c170b53]

Shawn, I don't think Blueldr comments were solely directed at you but his question was one that I know I've had to think about more than a few times. Likely the subject has been food for thought for not only those asking but those answering in our forums.
IMHO the rudder has to be one of the easier surfaces to rig as the cable tension is determined by the return springs, so I 'm thinking the plane you're designing may need at least red paint.

[spduffee]

Bruce, Jim, Blueleader,

Sorry if I came off a bit slanted. I guess I was in one of those moods when I read it.
Thank you Bruce for the instructions. If I understand correctly, you have outlined two things: One is a test of the return springs, with the cables detached. Part two is, with cables attached and the rudder at zero deflection I am tightening the turnbuckles until the pedals match, side by side. When I rigged the aileron, I held the yokes together and tightened the turnbuckles until the ailerons came to zero deflection. Based on that, I would have held the rudder pedals in place until the rudder came to a zero position.
I remember seeing it somewhere on this forum, but now I can't find it: The eye turnbuckles - one is Short, one is Long. They are called out in the drawing as 10 (passenger side) and 11 (pilot side). In the following parts description they are numbered 9 & 10, not 10 & 11: 9- AN165-22S and 10- AN165-22L. I have the long one on the pilot side, the short one on the passenger side. Is that correct?

--Coincidentally, the design I am working on is actually red and white.