C-170B Tailwheel spring Length

[N2782C]

A friend with a '50 C-170 was over the other day and i wanted to measure the length of the tailwheel spring from bolt to bolt. My (C-170-'54) was 16" and his was 14" in length. They are supposed to be the same part number as shown in the Cessna 170 Parts Manual. What gives?

Thanks...

[jrenwick]

Could you be comparing a 170A with a 170B? Those are different parts catalogs....

[N2782C]

The parts book I used was for the 170B. Tailwheel spring # is the same for early and late models. Does anyone know what the "A" model spring length from bolt hole to bolt hole is?

Thanks,

[voorheesh]

I just installed a new leafspring on a 170A (S/N 19225) and it was about 2" longer than the one I took off. I got the part numbers out of Cessna 170A parts manual from Univair and I got them from Univair. Part #s 542105, 542106, 0442108-2, 0442109-2. Had to get longer chain. I will measure it next friday and post.

[N2782C]

Hey guys...I hate to admit this but after careful consideration, picture taking and talking to a ton of 170 pilots I came to the conclusion that I had installed my main tailwheel spring improperly. I put the front bolt thru before the spring hole came in view (don't ask how) leaving me with a 16" difference between the front bolt and tailwheel bolt instead of the proper 14" or so. I just redid it and it is done properly now. And who says flying doesn't have some luck involved in it. I am one lucky pilot. I figure the only thing holding that spring in was the top spring retainer (brand new) and the "U' bolt + a little help from the steering springs. Whew!

[N2865C]

I tried to figure out how to reply tho this post anonymously , but no luck.... I did the same thing.... It's easy to do... I did the work and had it inspected and signed off by the best IA on the field... Flew it for 4 years until we discovered it during an annual. Fortunately it did not cause any damage.

[n2582d]

Here's a similar incident that had a lot more serious consequences. http://www.tc.gc.ca/CivilAviation/certi ... 000-05.htm

Aileron U-joint.jpg

[N2782C]

As I said...luck was on my side. If nothing else, this forum hopefully prevents similiar incidents from happening to those who take the time to read and learn.

[voorheesh]

Thanks for the tip. I'm the one who mentioned (a few posts up) that I just changed leaf springs and found I am about 2" longer. Could you provide a few more details on this? I haven't finished other work so I haven't flown it yet. I sure would like to get it right.

[GAHorn]

If the new leafspring is not inserted completely, it's possible to insert the bolt up thru the stack and totally miss the hole in the main leafspring. The bolt still clamps the stack, but the mainspring is not actually "captured" by the bolt.

[N2782C]

George has it exactly right. I did what he said. Didn't get the spring far enough into the receiver channel, put the bolt in and tightened it down, put the U bolt clamp on and thought I had it done correctly. With the new top spring receiver piece (don't have the name handy)that I installed it was very difficult to even get the spring up to the hole. It is indeed only 14" from hole to hole on the main spring and I should have checked more thoroughly when it came out to be 16" from bolt to bolt.

[voorheesh]

It sounds like that is what we have done. Did you have any trouble getting the new leaf springs in and lined up? The ones I got were from Univair and I think my mechanic had trouble getting them in the bracket. Is it possible you have to grind them to get them to fit? Thanks for any advice. BTW George, you get through Ike ok??

[GAHorn]

Dirt, mud, and tight fit all contribute to difficulty installing the replacement springs. I would not advise grinding on those springs. They are FAA-PMA and supposedly exact replacements. Look for the bracket and channels to have a "set" which may need relief.

Thanks for asking...My hurricane report: http://www.cessna170.org/forums/viewtop ... 426#p51426

[N2865C]

It sounds like that is what we have done. Did you have any trouble getting the new leaf springs in and lined up? The ones I got were from Univair and I think my mechanic had trouble getting them in the bracket. Is it possible you have to grind them to get them to fit? Thanks for any advice. BTW George, you get through Ike ok??

It was a B@&^!.... We finally had to just ever so slightly enlarge the holes it the tailwheel bracket to get the bolts in.... PMA'd or not, it was a tight fit.

[GAHorn]

That spring has two bends in it, and if attempting to install it with the rest of the stack already in place, it may be difficult to manuever it in the available room. It might help to remove the entire stack, pre-assemble, then install as an assembly.