Tailwheel Leaf springs replacement

[aaronhunley]

I've been debating if I need to replace the leaf springs. I don’t know how to determine if they need to. I’ve read on here that the main spring should be replaced every 500 hours, I haven’t found any logbook entry of it being done. So I was going to replace all of them. It also seems that the alignment of tailwheel is not right. Would replacing the springs bring the alignment more true? (I've read the posts with the Scott 3200 diagram)
I took a picture of springs and tailwheel, its not a good picture but I was hoping you guys could persuade me one way or the other.
Thanks

[GAHorn]

I don't know what you mean by "alignment"... (do you have the PN 0442011-3 spacer that adapts the tailwheel assy to the mainspring, installed?)..but if you have no record of the mainspring (that's the bottom one) ever being replaced... do so. Available from Aircraft Spruce or Univair. You do not need to replace them all...only the mainspring.

Replace the attaching AN7-20A bolt also. Or get the PN 0642105 eyebolt to accomodate a tie down rope.

[aaronhunley]

I don't know what you mean by "alignment"... (do you have the PN 0442011-3 spacer that adapts the tailwheel assy to the mainspring, installed?)..

Sorry bad use of words. (I probably do, never checked but will.)
What I was referring to was in the following picture, my tailwheel looks like the example of the top one. I’m hoping that if I replace the leafspring it would fix that…or do I have a bigger problem.
The reason why I was just going to replace them all was I thought the cost factor was close and I have to take it all apart anyways. I figured it’s probably original with lots of wear.

tws.jpg

[voorheesh]

I replaced all springs on 170A last annual and have been pleased with results. My old springs were a little shorter than the replacements I got from Univair (verified part #s and fuselage bolt holes all lined up) and the old ones were slightly bent. I am also thinking about sending my scott to alaska bushwheel in Joseph, OR. They will dissassemble and replace any defective parts. They are pretty reasonable and I believe they have an a&p who does the work and gives you a logbook entry for your mx records. If you search this site you will find good info on tailwheels and springs.

[DaveF]

and I have to take it all apart anyways.

Yeah, you do. You can't pull just the main leaf out of the stack. Put a C-clamp on the stack before removing the U-bolt and the main bolt. Then loosen the AN3 bolts that hold the "channel" and the spring stack should slide out. Without the C-clamp the stack expands and wedges in the bracket.

clamp on spring stack.jpg

Here's the old and new leaf laid on top of each other. They look the same, but I don't know if the spring constants are equal. The old spring had a notch worn in its top surface by the trailing edge of the next higher spring. George has written about that problem (many times, I'm sure).

old and new main leaf.jpg

[GAHorn]

Yes, the "notch" ... or "stress riser" is caused by the spring's sharp trailing edge which is just above the mainspring. Use a file to polish off that sharp edge to prevent damage to your new mainspring. (The stress-riser will eventually cause failure at that point.)

I have installed teflon tape on that mainspring between it and the spring just-above, to keep the mainspring from being so damaged. I'll see how it looks in 500 hours.

Here's a pic of the stress-riser ground into my previous mainspring in 500 hours.

MVC-001S.JPG

[cessna170bdriver]

deleted by the author

[GAHorn]

The Aircraft Spruce part is actually made by Univair and is a PMA'd part (but Spruce sells it for less money than Univair does. Just like the 170 Service and Parts books. Go figure.)

Yes, they all use the same mainspring. The Cessna PN 0542106 is the Univair U-0542106 is the Spruce 06-15100 and sells for $80.
http://www.aircraftspruce.com/catalog/a ... 0twspr.php

[KG]

Hi George,

On the Spruce web page referenced above, what is that other spring that is listed? Spruce part number 06-15000. Is that the whole stack?

I'm planning to replace my main leaf spring also as I can't find any record of it being replaced.

As a side note, the hanger that I've rented for the next couple of months is about 300 yards from Aircraft Spruce, which is turning out to be devastating to my wallet.

Keith

[GAHorn]

Hi George,

On the Spruce web page referenced above, what is that other spring that is listed? Spruce part number 06-15000. Is that the whole stack?

I'm planning to replace my main leaf spring also as I can't find any record of it being replaced.

As a side note, the hanger that I've rented for the next couple of months is about 300 yards from Aircraft Spruce, which is turning out to be devastating to my wallet.

Keith

If you "click" on the PN 06-15000 , you'll be taken to the following page, which describes it as a set of FIVE springs. It's very doubtfull anyone ever needs to replace all five springs.
http://www.aircraftspruce.com/catalog/l ... prings.php

[Bill Hart]

Keith,

Are you keeping it over at FFC not CCO?

[KG]

Hi Bill,
Yes, I was told there is a mulit-year waiting list for a t-hangar at Coweta County. Sent you a pm.

[aaronhunley]

Or get the PN 0642105 eyebolt to accomodate a tie down rope.

Does Aircraft Spruce have that, or do I have to get it from Air Repair Inc. A/C Spruce wants to know the AN # for their eyebots. I just want to be lazy and make one order.
Thanks

[GAHorn]

Aircraft Spruce does not sell the tailwheel eyebolt. PN0642105 is obtained from Air Repair.

[aaronhunley]

Well I ordered all 5 springs, and I'm here at the airport trying to put them in but...
When i pulled mine out i only have 4 single springs and the 5th one is bolted to the tail of the plane. The 5 springs that i got are all single. I called Univar they said to contacted the 170 org (haha).
There is also a spacer that slides into the springs where they bolt onto the plane, If i use all 5 springs that spacer is too small.
I dont have a digram here to look at right now.
So my questions are:
1. Do i use all 5 springs that i got or just the four that i pulled out?
2. Where would i get the spacer if i need all 5 springs?