Tailwheel steering cable issue

[BrianW]

Noticed that the tailwheel steering cables are not coming out of the fuselage at quite the correct position (see photos). This is on a 55 170B. Is this a known issue that should be addressed/repaired?

[GAHorn]

Well… it’s clear that the cable has been cutting into the tailcone skin and that’s not normal. You should inspect the rear bulkhead to determine that the tailwheel steering system pulleys are properly installed and aligned in accordance with the IPC.

Does your tailwheel steering springs consist of tension springs..?? or have they been replaced with Maule compression-springs (which can overstress the pulleys and rip them from their bulkheads and cause mis-alignment.)

934B2D1C-A965-4648-965F-BD92F4BDDA48.png

[BrianW]

Tailwheel has the standard springs. Tailwheel chains/cables are tight when on the ground, I just read in another post this isn't correct because they will tighten even more when unloaded. Sounds like a good place to start would be re-rigging this tailwheel, and inspecting the pulleys.

[GAHorn]

The steering does not “tighten” when loaded. It’s a common mis-belief that when the tailwheel is on the ground VS in the air that the tension changes. It does not. The tailwheel moves in an “arc”, the radius does not change (in the OEM configuration.)

This subject came up at the Branson Convention so we demonstrated on the ramp (using Steve Grimsley’s airplane which was/is configured as originally with a Scott 3200) that raising the tail off the ground makes no change in steering chain tensions.

The chains should be “taut” … not loose.

[BrianW]

The chains should be “taut” … not loose.

Thanks for clarifying that GAHorn.. I'll put my inspection camera in there today and see what the pulleys look like. Sounds like the cable tension is probably ok.

[daedaluscan]

I had an issue when I first bought my plane about ten years ago with one tailwheel cable slipping on the rudder cable. Its attached with what I call a ground cable clamp (its used here in Canada to attach or splice ground cables in house construction). If it slips on the rudder cable the tailwheel cables get loose, and as it moves further back its alignment changes out of the hole. Its an easy fix, but you have to remove the empannage to access it. While you are in there you can clean out crud, and check that the pulley mount has not started to tear the bulkhead.

[falco]

Anyone have any insight into why Cessna changed to this setup in 55?

The previous design is lighter, simpler, cheaper, more accessible, etc.

[daedaluscan]

I think it was meant to improve steering on the ground. I agree a solution to a problem that did not exist. I have contemplated taking it out, but since my initial problems it has not needed anything.

[bccubguy]

Hello
Also a good time to inspect your rudder cables with the tail off. On my 2100 hr. TT 1955 both rudder cables and tailwheel steering cables had broken strands.
does anyone know if there Is a torque specification on the tailwheel cables to rudder cables connection clamps.
Thinking if clamps are over tightened it could damage the rudder cables and if to loose tail wheel cables could slip.
Thanks in advance, Aurele

[n2582d]

Its attached with what I call a ground cable clamp (its used here in Canada to attach or splice ground cables in house construction).

Charlie,
I learned something new today. Thanks. Having a '52 C-170B which has the earlier style tailwheel steering, I had incorrectly assumed this connector was a u-bolt cable clamp like this:

Cable Clamp.jpg

The IPC, in fig. 65A-5, gives it the unusual part number of "8-H". Blackburn makes a split bolt connector with the part number of 8H.

Blackburn 8H.jpg

Is this what the clamp on your C-170 looks like? This website has a table which specifies the torque to be 80 in/lbs. That seems rather low to me. Maybe someone who knows more about these connectors can chime in.

[daedaluscan]

Yes the second picture is what I have.

One was finger tight when I got in there and slipping. I did not torque them, but they have not slipped since.

[mschlender]

If I remember right there is guides for the cables just inside but have to pull tail to get at them

[Vertical]

Anyone have any insight into why Cessna changed to this setup in 55?

The previous design is lighter, simpler, cheaper, more accessible, etc.

Has anyone ever converted back to the pre-55 cable setup? I wonder what the weight savings would be if you removed the extra cable and pulls etc.

[bccubguy]

Thank you for the torque specification. Aurele

[JohnNielsen]

When I rebuilt my '55 170B s/n 26712, we contacted a tech engineer at Cessna who was kind enough to do research and advise us. He said they tried that complex cable pulley system to attempt to get better tailwheel movement with rudder pedals. After a few they decided it was not worth the trouble and weight and went back to simple attachment of tailwheel to the rudder arm. He suggested we leave those parts and cables out of this plane and do what the factory dd a few s/n down the line. That is what we did and I am happy for that!!

John