Tailwheel Steering Springs and Chain Kit x

[GAHorn]

There is a misunderstanding by many as to which set of steering springs should be used on our tailwheels.

The ORIGINAL tailwheel was the little Scott solid-rubber 2400 which used the lightweight steering springs, Scott PN 2151 . This is sold in a kit by Aircraft Spruce, for about $51. It is NOT what most of us use.
http://www.aircraftspruce.com/catalog/l ... prings.php


The steering springs most of us use are Scott PN 3239, Aircraft Spruce PN 06-000008 which is also sold in a kit for about $52.
It is a much heavier-duty spring, about 4-1/2 inches long from hooked end-to-end, and has about 2-3/4 inches of coils made of 1/16-inch wire.

EDIT: http://www.aircraftspruce.com/ and in the search-box, ENTER 06-00008 to find the correct heavy duty springs Scott PN 3239.

Hope this helps.

[jrenwick]

....Here's a convenient link to use to order:
http://www.aircraftspruce.com/neworderf ... -00008&q=1

Hope this helps.

Be careful if you use this link, folks! It will put the springs in your shopping cart, and if you don't remove them, you may be getting a pair with your next Spruce order!

[GAHorn]

....Here's a convenient link to use to order:
http://www.aircraftspruce.com/neworderf ... -00008&q=1

Hope this helps.

Be careful if you use this link, folks! It will put the springs in your shopping cart, and if you don't remove them, you may be getting a pair with your next Spruce order!

Well...actually, no it doesn't. One would have to click on "Check out" to place it into your actual order. But it DOES do a crazy thing when you visit the link, leave, and then return to it.....it keeps adding to the numbers of kits you might order!

I went back and edited my previous post to give what is hopefully a safer link. Unfortunately Spruce made it complicated to get the correct part....and easy to get the wrong part.

[LBPilot82]

Well, about a year ago, I replaced my compression steering springs with the original scott 2151 springs from spruce. Like most, I've got a Scott 3200 T/W. My steering on the ground leaves much to be desired as most all of us do. I ordered these heavier duty springs and got them today. They are MUCH heavier duty than the originals. My concern is that these heavy duty springs could have the same effect as compression springs on the rudder cable system. Yes they have "give" unlike the compression springs but boy does it take a lot of force to pull them. Are many of you using these springs and not having problems? Cessna designed the rudder cable system to withstand a certain amount of load and these springs will certainly increase this load if used. Maybe I'm missing something.

[GAHorn]

Well, about a year ago, I replaced my compression steering springs with the original scott 2151 springs from spruce. Like most, I've got a Scott 3200 T/W. My steering on the ground leaves much to be desired as most all of us do. I ordered these heavier duty springs and got them today. They are MUCH heavier duty than the originals. My concern is that these heavy duty springs could have the same effect as compression springs on the rudder cable system. Yes they have "give" unlike the compression springs but boy does it take a lot of force to pull them. Are many of you using these springs and not having problems? Cessna designed the rudder cable system to withstand a certain amount of load and these springs will certainly increase this load if used. Maybe I'm missing something.

Like I said, the heavy-duty 3239 springs are the correct ones for the Scott 3200.

[cessna170bdriver]

George,

You might want to consider editing the typo in the title in case someone ever does a "titles only" search with the keyword "tailwheel". I've been following this thread since it started and just now noticed.

Miles

[N2255D]

Are many of you using these springs and not having problems? Cessna designed the rudder cable system to withstand a certain amount of load and these springs will certainly increase this load if used. Maybe I'm missing something.

They came on the plane and have been there since 1996. Never had a problem with them.

[Bruce Fenstermacher]

Are many of you using these springs and not having problems? Cessna designed the rudder cable system to withstand a certain amount of load and these springs will certainly increase this load if used. Maybe I'm missing something.

LB I've looked at a lot of 170s over the years. The majority have the correct larger steering springs. The next most found steering spring at probably 1 in 7 aircraft is the Maule compression spring. I can't recall but I probably have seen a few 170s with the smaller tension spring.

So by far there are much more installations of the larger tension spring and no reported difficulties that I'm aware of.

I believe the Maule compression spring has been chosen because of marketing. Owners looking to fix a shimmy problem with the wrong part not knowing better. And over the years there has been reported damage because of the limiting factor of the compression spring design not from the tension on the system from either style spring.

I would not be surprised to start seeing the incorrect smaller springs being installed more often, again because of marketing or lack there off. As we have noted you won't find the correct spring in the Spruce catalog. So if you don't know what your looking for and don't know to ask you will get and install the wrong spring whether it be the small version or the Maule spring.

[blueldr]

The hand wringing about tail wheel steering on the Cessna 170 over the years has been truly excessive. Basically, a great many of them don't steer worth a damn using the rudder pedals. They steer just fine with a small amount of differential braking, and that's the way I've always operated. Any short turn at all will require the use of the brakes anyway. I just figure the springs as being used to take up cable slack and they need'nt be stronger than necessary for that job.

[GAHorn]

George,

You might want to consider editing the typo in the title in case someone ever does a "titles only" search with the keyword "tailwheel". I've been following this thread since it started and just now noticed.

Miles

Noticed what??? (Thanks)

[robert.p.bowen]

The best price on the correct spring for a Scott 3200, together with the connectors and chains, is from Air Repair, Inc. I just bought one and it was about $35.00. Probably for an L-19, but it's the same spring kit. Even comes with install instructions that finally put to rest how to tension the chains ("just slack" per Scott, with the weight off the tailwheel).

By the way, Blueldr has it right (in my opinion) -- if you count on tailwheel steering to turn the airplane, you can and will ultimately bend the steering arms. I've gone to using brakes for turning, and tailwheel steering for landing and take-off swerve control.

[GAHorn]

It's a shame that the marketing dept's of mfr's allow their secretaries to write installation instructions. That tailwheel fits many, many airplanes. The airframe mfr'r is the one most qualified to provide installation/rigging instructions.
The tailwheel steering chains should have NO SLACK...they should be "just taut". (If they ain't tight...then how the hell they gonna influence steering?)

If steering arms bend it's because Scott made them out of soft materials (because when they were acquired by TYCO, (you remember them,...the guys run by hedge-fund executives that got into trouble...doubtless somebody who knows all about tailwheels...)....they retired all the knowlegeable old-timers and had newbies on the mfr'g lines)....until somebody pointed out the problem. They corrected it with proper mat'ls and no bending problems anymore, unless you used the incorrect compression springs.

[lowNslow]

Seems it is a pretty fine line between "just slack" and "just taut". I'm sure there is a big difference in steering.

[robert.p.bowen]

Wish I could agree with you on this one, George, but I can't. I converted my Scott 3200 to a 3200A--the one with the much stronger and broader steering arm. It still bent, and this steering arm was manufactured by Scott in the late 1960's. Don't know when Tyco took over, but I bet it was after that.

One reason why our steering arms are at more risk of bending is the sharp angle the chains make pulling up on the steering arms. The geometry is anything but a straight pull.

It's a free country and it's your money, so shower down on the rudder to steer on the ground if you wish. When the steering arms bend, blame George, not me. I stand by Blueldr; he has it right.

And by the way, with the chains just slack, it steers perfectly fine. All you do is move the rudder maybe another 1/4" as contrasted with chains that are taut. It's not a big deal, and rigging as Scott suggests (and that instruction is specifically for the Cessna 120,140 and 170 per the sheet) is gentler on parts in the tailwheel assembly.

George, what's your source for saying the installation instructions were written by a secretary in the marketing department?

[GAHorn]

...George, what's your source for saying the installation instructions were written by a secretary in the marketing department?

What is anyone's source proving any different? You got an engineer's signature on your instructions? (I do. On a blueprint that shows the chains TAUT.)
I know that 10 years ago, when I called Scott and talked to "Don", who claimed to be the last of the original employees and who was about to retire, he told me that there is virtually no agreement within the company on much of this. When I asked if he had a copy of the Army TM-44 for overhaul/rigging of that tailwheel, he told me "no" that I'd have to get a copy from the Army. I've never been able to find a copy, the GPO doesn't have a copy either. (But he is the one who pointed out the U.S. Army had their own manual because they did not consider the Scott documents reliable.)

The Scott instructions in the I-168 document (the one which describes the approved installation) specifically indicates NO SLACK when they state: " Use sufficient chain links to remove slack in each connector assembly on installation."

The instructions accompanying the Dept of Commerce's letter of approval to Scott to install the tailwheel on C120/C140/C170 aircraft specifically states: "When connecting the springs, the stretch should be no more than 1/8" to 1/4"." That is certainly indicative of NO SLACK if there is specified "stretch".

I challenge you to find a genuine Cessna photograph of the tailwheel installation that has ANY slack in the steering chains. There are two such illustrations in the Owners Manual for the '53 B-model and in both pics the chains are taut. Even the Scott drawing which depicts the steering chains show them TAUT.

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