RUDDER STEERING SPRINGS

[Showboatsix]

Who makes a good set of steering springs? Compression or tension, which is better, which gives better feel?

I bought a set of compression from Aircraft Spruce, but the assembled length between the two springs, one is .125 shorter than the other one. This makes it hard to center the rudder and the tailwheel at the same time. I have not found a good generic spring of proper tension to replace what Spruce sold me.

Any suggestions?

[GAHorn]

I don't believe there's any approval for compression springs use on a 170. They may cause damage in certain cases. (Once they've compressed to their limit they do not allow further stretch and something's gotta give... probably your rudder-cable pulley-mount brackets. They may pull loose tearing sheet metal.)

[Showboatsix]

This is not on a C-170 but is on my 56' C-172 with STC conventional gear conversion, however the STC does not even address the rudder steering springs or chains, this STC was approved in 1988, and I think maybe the FAA was a little friendlier then as opposed to today. There are several things they failed to address in the STC, such as , the tailwheel steering, the C-170 vs C-172 oil dipstick, the top skin for the gear box carry through, .030 vs .050, are just a few of the areas left unatended in the STC.

This is why I am asking these questions.

[GAHorn]

I saw that rudder and don't know why I didn't take notice.

I'd still avoid the compression springs for the same reason as previously stated, and an added reason is that when the compression springs bottom-out they will contribute to bending your steering arm and rudder bellcrank.

Here's a tension spring set sold by Spruce (although I don't believe them to be genuine Scott):

http://www.aircraftspruce.com/catalog/l ... prings.php

[JHKeeton171]

I also have a 1956 C-172 converted to taildragger. It had compression springs on it when the previous owner acquired it. When we were looking at it for purchase the steering arms were severely bent upwards and his comment was that he had already replaced the steerings arms six times in the previous couple of years at $200 a pop and was reluctant to change it again. As part of the pre-purchase inspection we had him put on the tension style springs recommended by Scott and replace the steering arm assembly. Several hundred hours and many landings later, not a single bent arm. Got the springs from Aircraft Spruce. The latest catalog only shows a "Lighweight Spring Kit Scott" P/N 2151 $50.75. If my memory serves me correctly, they use to also have a heavy duty spring kit, but I don't see it listed. Ground handling and steering, takeoff and landing are still excellent.

[Bruce Fenstermacher]

The Scott or Spruce light duty springs are for Cubs and Champs and would be inadequate in my view for a 170.

[Bruce Fenstermacher]

I just called Spruce. You are looking for the 3239 Heavy Spring Connector Kit. It is Spruce part number 06-0008 and current list sell for $48.75. They have 7 kits in stock in Georgia.

Univair also lists this kit but sells it for a Piper and probably also the Stinson. I believe the part number in U3239-101 SPRING CONNECTOR KIT-PIPER but check with them to confirm it is just the Scott kit. Price from Univair on-line is $41.93 but don't know if this is accurate. If you only need the springs it appears Univair might be listing them separate under part number 3239-1 @ $6.90 but check with them to confirm this is the same spring as their kit.

Pictured is the correct spring next to a quarter

Correct spring with a quarter

[Showboatsix]

Thanks for all your help, I will order a set of the HD springs from Spruce tomorrow.

[blueldr]

Actually, it's a helluva lot less expensive to go to your local hardware store and look over their miscelenous spring collection. My steering springs cost about $3.50 and work just fine.

[GAHorn]

Actually, it's a helluva lot less expensive to go to your local hardware store and look over their miscelenous spring collection. My steering springs cost about $3.50 and work just fine.

Yeah, but you don't fly at NIGHT!!

[blueldr]

If I have to fly at night, I can always change the springs.

[GAHorn]

I don't believe there's any approval for compression springs use on a 170. They may cause damage in certain cases. (Once they've compressed to their limit they do not allow further stretch and something's gotta give... probably your rudder-cable pulley-mount brackets. They may pull loose tearing sheet metal.)

Here's pics of what can happen when compression type tailwheel steering springs are used on a Cessna 170..... they compress...become SOLID... and overstress the rudder steering cables until it causes them to rip the pulley's out of the bulkheads!

[DaveF]

Univair also lists this kit but sells it for a Piper and probably also the Stinson. I believe the part number in U3239-101 SPRING CONNECTOR KIT-PIPER but check with them to confirm it is just the Scott kit. Price from Univair on-line is $41.93 but don't know if this is accurate. If you only need the springs it appears Univair might be listing them separate under part number 3239-1 @ $6.90 but check with them to confirm this is the same spring as their kit.

I called Univair today and they confirmed that the 3239-1 spring is the spring in the kit.

[1SeventyZ]

Just to expound on the cons of using compression springs...

I am an avid Telemark snow skier, which is characterized by a special free-heel binding that anchors only the front of the boot. A special skiing technique is used that requires that the heel of the uphill foot is lifted off the ski in turns as the uphill knee is bent. The binding uses compression spring cartridges inline on a cable to retain the boot in the binding, and also provide a little resistance in lifting the heel.

It's common for the binding to be improperly adjusted, or the wrong spring cartridge to be used. In this case, when the heel is lifted dynamically during aggressive skiing, the spring cartridge can "bottom out", transferring all forces directly to the screws that hold the binding to the wood ski core. I've seen numerous bindings ripped totally out the ski because of this.

Some principle as the bulkhead pulley attach failure above.