Tail wheel spring

[akmacon]

Hi All
I am a new member , I have a 1953 170b and the tail wheel spring looks very rough and old and over 500 hours. I plan to replace it or new main leaf and overhaul, what are the best options and where to get the best prices.
Thanks Alan

[bagarre]

Welcome to the 170 Association.
Did you join the Association or just the forums?

I bought my tailwheel spring from aircraftspruce.

http://www.aircraftspruce.com/catalog/a ... 0twspr.php
The price seemed fair enough.

Also, make sure you have a steel lock nut for your tailwheel bolt. There have been reports of the nylon locknuts working lose.

There are quite a few threads on the forum about the tailwheel springs as well. Be sure to search the forums for more information.

[Bruce Fenstermacher]

Spruce or Univair pricing is within a few dollars as I recall and the spring will be made by Univair either way.

And yes as indicated by his avatar Alan is a TIC170A member.

[bagarre]

I never knew that's what the avatar meant.
Learn something new every day.

[blueldr]

David,
Best you use caution learning something every day. A brain can only hold so much, and then it will be full. I had the unfortunate habit of learning too much at too early in life. I will be ninety next month and I haven't been able to learn anything new for twenty years.

[bagarre]

(This thread probably should be split as we're no longer talking about tailwheels)

90 years next month! Congratulations! Where's the party going to be?

I don't think I'm in danger of filling up my brain any time soon. For the first 25 years of my life I don't think I learned a single thing. I had a lot of fun but didn't learn much

Regarding tailwheels:
This was the thread I was thinking about:
http://www.cessna170.org/forums/viewtop ... ile#p69144

[swixtt]

I've read a few of the threads on replacing the spring but not sure why some did the whole pack and others just the main? If I'm after correcting my angle will the main suffice? I have not removed anything yet so can't verify the condition of the pack.... No idea when these were ever changed either.
Thanks

[Bruce Fenstermacher]

I could never understand why someone would change out the whole pack unless they felt the pack was a mismatch of incorrect springs. Likely they don't understand the failure point which is the main spring bending back against the next shorter spring. There are people who figure if replacing the main spring is good, replacing all of them is better. I don't describe to that.

For the most part the tailwheel angle is set by the down bend in the main spring. Of course again if the others are a incorrect mismatch and their angle not close the new main will likely not hold a good angle along it's main part and the bend at the end will not place the tail wheel angle correctly.

So I would replace the main and inspect, clean and paint the rest of the old pack.

[swixtt]

Bruce, that answers it. Thanks for the explanation.

[bagarre]

I would round off the cut edge of the spring that contacts the main spring so it doesn't tend to wear a groove in the mainspring.
The worn groove can cause a stress riser, increasing the chances of man spring failure.
2 seconds with a grinder or file will do the trick.

[canav8]

Corrosion is the biggest reason for replacing the stack. The main spring like Bruce said is the one that has the life limit.

[swixtt]

Great, thanks for the reminder on prepping the other spring. Bruce mentions paint... can they be powder coated?

[canav8]

Great, thanks for the reminder on prepping the other spring. Bruce mentions paint... can they be powder coated?

Not recommended for spring steel. Others may have a different opinion but anytime you put heat to spring steel the possibility exists to change the molecular structure of the metal. I guess it depends on how much heat is used to cure the powder coat. I think 400 degrees is not safe. A good epoxy paint is the safest bet. IMO

[rydfly]

Corrosion is the biggest reason for replacing the stack. The main spring like Bruce said is the one that has the life limit.

Wear is another reason to do it. I replaced just the main spring when I purchased our 170 about 6 years ago as there wasn't any logbook notation of it ever having been done. It definitely needed it and did a lot to correct the angle (and related TW shimmy). Once I had the stack out, I could see how every spring was worn from 60+ years of sliding over the top of each other, with the main spring being the worst. Next time I replace the main, I'll replace all of them. I expect the new shorter springs will be good for another 60 years after that!

[canav8]

Corrosion is the biggest reason for replacing the stack. The main spring like Bruce said is the one that has the life limit.

Wear is another reason to do it. I replaced just the main spring when I purchased our 170 about 6 years ago as there wasn't any logbook notation of it ever having been done. It definitely needed it and did a lot to correct the angle (and related TW shimmy). Once I had the stack out, I could see how every spring was worn from 60+ years of sliding over the top of each other, with the main spring being the worst. Next time I replace the main, I'll replace all of them. I expect the new shorter springs will be good for another 60 years after that!

Rydfly, sorry that the literal sense on the statement came across. Most guys have replaced their stack because they dont know the life limit of the main spring and they replace the whole thing. The life of the stack is not in question in 500 hours but the main spring is. Generally corrosion is a big concern because if the stack was not treated correctly like a previous poster mentioned about deburring the manufacturing burr on the end of the spring from shearing, it will cause stress cracks. That point is also where corrosion is common especially for outside birds. Sorry I didnt explain further. D