Annual surprise!

[ak2711c]

I don't think 4stripes is advocating floppy loose chains. If you adjust the chains tight with no weight on it then when you set it down the slack is barely perceptible. If you adjust the chain tight with it on the ground in just a matter of hours it will bend the steering ears on the tail wheel up slightly until the chains are the same tension as if it where adjusted tight in the air. I am surprised you are not aware of this George as long as you have been around 170's. The 170 is the only aircraft I am aware of though that needs to be adjusted that way. The geometry of the tail wheel steering on most all other planes is such that weight on the tail has almost no effect on the tension of the chains. Although the 56' model 170B steering has much better geometry than the earlier ones and I would bet you could adjust it ether way with no problem.
Shawn

[GAHorn]

I don't think 4stripes is advocating floppy loose chains. If you adjust the chains tight with no weight on it then when you set it down the slack is barely perceptible. If you adjust the chain tight with it on the ground in just a matter of hours it will bend the steering ears on the tail wheel up slightly until the chains are the same tension as if it where adjusted tight in the air. I am surprised you are not aware of this George as long as you have been around 170's. The 170 is the only aircraft I am aware of though that needs to be adjusted that way. The geometry of the tail wheel steering on most all other planes is such that weight on the tail has almost no effect on the tension of the chains. Although the 56' model 170B steering has much better geometry than the earlier ones and I would bet you could adjust it ether way with no problem.
Shawn

What he said was:

...If they have no slack when the plane sits, they are too tight. ...

That implies the chains should be slack. (slack sounds like floppy, loose to me.)

There is no lack of awareness on this subject on my part. I own a 170B and my chains are taut with my tailwheel on the ground, just like Cessna and Scott both intended and intruct. My tailwheel does not bend it's steering arms (ears) up at all. It has no shimmy. It works just like it's supposed to work. When I push on my rudder pedals, my rudder moves and it, in-turn, moves my tailwheel. When it is in the air, the tension springs stretch and allow the tailwheel to descend...just like the springs were intended to do.

There was a set of steering arms which got out into the marketplace which did not meet specifications, as they were too soft and/or made of improper materials and were subject to bending. The best cure for that situation was to replace the defective part.... not add another error on top if the one already existing. That situation should not be addressed by yet-another improper maintenance habit (of slack chains) but should be repaired by replacement with correctly annealed/tempered arms. (Although some folks got fed up and simply swapped them out with the 3200A "upturned" arms... not a disqualifying mod.... but not necessary either.)
The anecdotes, ad-hoc repairs/mods/alterations that some folks do to these tailwheels are numerous. None of those actions will properly address incorrectly maintained/adjusted/modified tailwheel set-ups, and it is incorrect to try to get others to adopt improper techniques/mods that some folks have mistakenly pursued. There's nothing better than good maintenance performed according to mfr's specs. There's no reason to try to invent the (tail) wheel. Just do it right and quit trying to convince others to do it wrong.

[4stripes]

With all due respect, I've had the tail chains with no slack, and now (for some years) with some slack. Tailwheel control was always somewhat sloppy (response, not my control). The rudder, and brakes provide the lion's share of control (accompanied by proper use of ailerons and elevator). My tailwheel was brand new when I had it installed with no wear, or improper replacement parts. Thinking that the 170 can be controlled simply by the chains pulling left or right is laughable.
When my rudder bellcrank was removed I could not believe the wear caused by the downward force of those "properly installed" chains (and springs). I wish to keep my rudder in good shape for as long as possible (along with every other part). I have noticed no loss of control with the change. There are numerous tailwheel aircraft that have no direct control of the tailwheel as the rudder provides control (on the ground as well as in the air). There are also many trike and amphibious types that also omit steering linkage (some with scott tailwheels I might add).
I'm hoping there are no hard feelings George but in this case I will agree to disagree on this subject.
Cheers Eric

[GAHorn]

No hard feelings at all, and none were intended by me. I understand what you mean by the "laughable" steering capabilities of the tailwheel installation on this airplane.... True... brakes do a lot of the work and rudder input is merely "encouragement" for the tailwheel steering.

[jrenwick]

I'm just sitting back here, reading all this discussion of cables, springs and chains, and thinking it probably doesn't apply to the later B-model with the TW steering cables that attach to the rudder cables inside the fuselage. Am I right?

John

[blueldr]

George,
We're further west out here and the air coming in off the Pacific Ocean is considerably thicker than the air off the gulf. I've discovered that if the tailwheel doesn't properly turn with the rudder in flight, the adverse yaw becomes a problem in properly coordinating turns in the C-170. This can progress into a violation being filed against you by air traffic control for performing turns that are either greater than or less than standard rate. Out here they'll file on you even if you're VFR and taxiing on an uncontrolled airport.

[N171TD]

If the mfg recomemdations were always correct then there would never be corrections ( right ?)

[Bruce Fenstermacher]

John you are right the later cable run is different.

I've been down this road before. My feeling is like Eric that the chains shouldn't be tight but with no slack when the tail wheel is off the ground, which is when they tighten, to avoid excessive wear. But then the chains are very slack when needed on the ground and what ever steering assistance they may provide is even less effective.

I also can't find any documentation to refute George's points that Scott (and Cessna) intended there to be no slack with the wheel on the ground and that the point of the springs is to allow then to stretch and make up the difference with the wheel in the air.

In the end I think George is probably correct and that Scott and Cessna didn't care about the wear because that is why they made replacement parts.

I personally compromise a bit. My chains are adjusted to give a very slight amount of slack on the ground and therefor less tension while the wheel is in the air. I've found no detectable loss of control authority on my aircraft this way over having them with no slack and I have more piece of mind I'm doing what I can to minimize wear.

[Bruce Fenstermacher]

N171TD you make a VERY good point. And to say that the lack of a correction validates the instructions doesn't completely hold water with me either. Scott and Cessna have long ago forgotten these instructions and aren't about to open any wounds by issuing corrections. Opening them up for more liability.

[GAHorn]

Both Hawkeye and Eric have '52 B-models. (They have the early, direct-steering mechanism.) Perhaps if the tailwheel chains were taut, they might help off-set the constant pull from the rudder return springs on the bellcrank and less wear might occur on it.

Which would be the greater liability? Knowing a service instruction to be incorrect and correcting it? Or knowing a service instruction to be incorrect and deliberately allowing the error to exist and continue to be incorrectly serviced?