Tailwheel Assy ATTACH bolts/nuts

How to keep the Cessna 170 flying and airworthy.

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Joe Moilanen
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by Joe Moilanen »

I did exactly that, installed a "C" shim in mine to stop radial play. I've been replacing at least my main spring every 500 hours and it needed it on the first replacement which was a couple of decades ago so the replacement main leaf was slightly too narrow even back then.

Joe
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wingnut
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by wingnut »

Joe Moilanen wrote:I did exactly that, installed a "C" shim in mine to stop radial play. I've been replacing at least my main spring every 500 hours and it needed it on the first replacement which was a couple of decades ago so the replacement main leaf was slightly too narrow even back then.

Joe
Joe, do you recall where you purchase the first and subsequent springs?
Del Lehmann
Mena, Arkansas
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GAHorn
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by GAHorn »

Those videos are excellent info. Thanks, Del and Aryana!

I am in recp't of one of our Member's mainsprings which broke at exactly that point. (Ordinarily they break where the No.3 spring wears a stress-riser onto the upper surface of the mainspring, however this Member's spring ...an L-19 spring, in fact... broke where the shim clearly had been wearing on the mainspring.

The point is that the bolt MUST be tight! and the shim should prevent all wobble/wear on the mainspring. This should be an ANNUAL INSPECTION item and remember, replace that mainspring every 500 hours and/or landings.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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gfeher
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by gfeher »

I need to change the main spring on my '52 B model (with a Scott 3200). So Del, I'm particularly interested in how you correct the side-to-side movement shown in your videos, whether with shims or otherwise.

In the meantime, I have a related question. When I change the main spring, I'm going to change all of the nuts, bolts and washers (including the U-bolt). Is it worth it to also change some of the other bit parts (if economical)? The parts I'm talking about are the stiffener (p/n 0510000-33), shackle (p/n 0542108), guard (p/n 0442125), bushing (fuselage end) (p/n 0510000-36), shim (p/n 0510000-30) and bushing (tailwheel end) (p/n 0442011-4). I have not checked to see if they are readily available. But if they are, should they be changed periodically, or are they pretty durable so they only need to be changed when they show signs of failure or serious wear?

Thanks in advance.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
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GAHorn
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by GAHorn »

Gene, they are readily available but ... you should inspect yours and replace them based upon condition. There is little to be gained replacing most of those parts unless they show wear or deformation.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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wingnut
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by wingnut »

Caution!!!! Long post. Grab a cup of coffee......

Gene, I would always replace what I refer to as "generic" hardware items. Other items should be replaced on condition.
As for "my" remedy to the imperfect fitment allowing some radial motion, I have not even began to study the best solution. I'm not even sure a real problem exist other than worn parts. Because of this forum discussion, I looked at 3 planes in my hangar and found they all had the same issue to varying degrees ( the videos Aryana posted for me are all the same plane, an L19). I will study this further. It could be that new parts are the solution, however I also think a tolerance fit of the spring to Scott fitting would certainly be a good fix. I don't think that is a viable option from the OEM or aftermarket manufacturers. So, I may be premature in suggesting an addition shim.
Several folks have mentioned this recurrent loosening of the the bolt, and my opinion is that this could not happen unless there exist another problem with excessive spring to fitting fitment tolerance.
I have personally tried different hardware in this location. George's recent post proves this is not a solution (I believe we used a new L19 eyebolt, and a new steel lock MS21045 in lieu of the nylon lock nut, and I think we also added a split lock washer. After installation, I think we placed a dab of torque seal so it could be monitored. George Please correct me if I'm mistaken. I may have your aircraft mixed up with someone else). After the brief inspection of all 3 planes here, I'm thinking the best solution will be to fab a thicker shim to replace the existing one, or to fab a thinner one to add in combo with the existing shim. From what I have observed, no amount of torque, Loctite, torque seal, etc. will prevent the eventual loosening of this assy without an initial proper tolerance or interference fit to eliminate possibility of radial movement. The torque moment on that bolt during ground ops is far more than the torque spec for the bolt/nut, so it is not unreasonable to conclude that any movement could only result in reduced torque on that bolt, whether it be from the nut actually rotating, or from wear on the mating/bearing surfaces that same bolt compresses together.
Del Lehmann
Mena, Arkansas
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gfeher
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by gfeher »

OK. Thanks Del. All good information.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
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wingnut
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by wingnut »

If anyone has there aircraft down for maintenance or has opportunity to lift the tail and inspect, I would like feedback on your findings. Once you get the tail wheel off the ground, loosen the bolt and then tighten it just enough that surfaces contact. Then rotate the assy and observe how much radial movement there is. Don't forget to re torque when you're done :wink:
It will be interesting to get this info from a larger group, and also not a bad idea for everyone to take this request as an opportunity for inspection.
Del Lehmann
Mena, Arkansas
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Joe Moilanen
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by Joe Moilanen »

wingnut wrote:
Joe Moilanen wrote:I did exactly that, installed a "C" shim in mine to stop radial play. I've been replacing at least my main spring every 500 hours and it needed it on the first replacement which was a couple of decades ago so the replacement main leaf was slightly too narrow even back then.

Joe
Joe, do you recall where you purchase the first and subsequent springs?
Del,

I believe that the last couple of springs came from Spruce and Specialty, one of the first ones came from Univair, and can't recall some of the ones in-between. I noticed the radial play on the first one that I replaced, made a shim, and have had to use it on every replacement since though.

Joe
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GAHorn
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by GAHorn »

The mainsprings sold by Aircraft Spruce are PMA'd by Univair and supplied to Spruce.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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Joe Moilanen
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by Joe Moilanen »

gahorn wrote:The mainsprings sold by Aircraft Spruce are PMA'd by Univair and supplied to Spruce.
That makes sense then. I know that the spring that was on the plane when I bought it in '89 fit snug though, and noticed the width reduction on the first one that I purchased. It could have been an original but I seriously doubt it.

Joe
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gfeher
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by gfeher »

Anyone know whether the Scott 1 3/4" to 1 1/2" adapter (Spruce p/n 3241-1S) is the same as Spacer, item 4 (p/n 0442011-3) in Fig 94, pp. 154-155 of the B model IPC? It appears to be so, but I don't want to shell out $50 or so to Spruce without knowing for sure.

I'm changing my main leaf spring and I noticed when I jacked it up that there was slight rotational movement at the wheel end (both with the original and new main leaf spring - about 1/16" measured at the forward end of the Spacer). I noticed slight wear at the forward edged of the spacer, which may be allowing the movement. I'm hoping a new spacer will prevent such movement. (BTW, the new spring is the same width as the old spring, so I don't think the rotation problem many of us are having is due to spring width. I suspect it's caused by spacer wear.)

Thanks,
Gene
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
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gfeher
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by gfeher »

Well, I think I've answered my own question. I've run across some threads indicating that others have used 3241-1S (actually its a Scott p/n) for the spacer. (There are a lot of threads on the tailwheel springs - I just missed it in the first go around.) Also, it's Univair that sells it for about $50 ($59.50). Spruce sells it for $69.75.

Sorry for the distraction.

Gene
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
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DaveF
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by DaveF »

Let us know if this solves the problem. My tailwheel has the same play you described.
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gfeher
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by gfeher »

I will Dave. I ended up ordering the spacer from Air Repair. Just the spacer is Scott p/n 3241-3S. (3241-1S is a kit that also includes the bushing and a couple of clevis bolts.) Air Repair's price: just $6.32. Gotta love Air Repair.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
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