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 »

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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GAHorn
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by GAHorn »

Yes, that item 4 appears to be the spring width adapter.
'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 »

Dave,

I received the new spacer (Scott "Adapter" p/n 2341-3S) from Air Repair, and I compared it to my new main leaf spring. While it eliminates almost all of the side play, it allows a very slight amount of movement (this is "dry," i.e., without tightening the nut). I've compared my old main leaf spring to the new one (Univair p/n U0542106) and they are the same width. So the slight movement is not due to any change in the width of the leaf spring. When I slipped two pieces of standard copy paper between one side of the new spring and the inside corresponding side of the spacer, I was able to eliminate the last bit of play. Those two sheets measured out at a total of .007" thick --not much but enough to allow slight movement. (The movement is very slight -- just enough to be noticed.)

I suspect that the slight movement will seem to disappear when the nut is properly torqued. But I'm concerned that over time the movement may re-appear (particularly if the nut slightly loosens) and cause further wear widening the space and potentially allowing further movement. Whether 500 hours (until the next main leaf spring change) is enough time for this to happen and cause significant wear is the question. The leaf spring I just changed was put on over 1300 hours ago, but my logbook doesn't mention whether the spacer was changed at the same time. So I don't accurately know how long it took for my old spacer to wear to its present state. It may be, though, that 500 hours is not enough time for enough wear to occur in the spacer to worry about.

My original main leaf spring was painted over in some areas by one of the previous owners, and just for kicks, I slipped the new spacer over those painted areas, and low and behold, the spacer fit perfectly in those areas -- no movement. So adding a coat or two of paint to the area of a new leaf spring that fits within the spacer may the answer -- a simple fix to get a tight adapter.

Finally, my IA has a lot of time and experience repairing and servicing tail wheel aircraft, including an L-19 that he has maintained for years for the local glider club. He says that in his experience, both fiber and all-metal locknuts on the tail-wheel end leaf spring bolt will loosen over time. He now only uses a AN7-20 bolt with a castellated AN310-7 nut (with cotter pin) on the L-19 he maintains. (I know that the folks who like to use an L-19 tie-down ring bolt for that end will not like his advice. Just passing it along.)

Sorry for the long-winded post, but I thought others might be interested.

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 »

The previous owner got his money's worth. I'm guessing I dodged a bullet.

Thanks Arash. Good info, as I was leaning towards not worrying about the small remaining gap given the recommend 500 hour replacement interval.
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 »

Thanks, Gene. Here's my adapter. The wear marks visible in the picture aren't quite as deep as they look, but as you said, it doesn't take much gap to allow a lot of movement.
TailwheelAdapter.jpg
bagarre
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by bagarre »

I just had my tail wheel off yesterday and my spacer, which is aluminum, has a slight side to side play as well. Maybe 3 degrees each side at most. I forgot to take a photo but it was in good shape with minimal anodizing worn off.

The bolt and steel lock nut was as tight as the day I put it on with torque seal to prove it. But I rarely 3point so my tail takes less of a beating than others might.

While everyone is eyeballing your tail springs, be sure to pump those two zert fittings full of grease. My last tie down flooded and submerged the tail wheel. Water got in and wrecked the bearings due to lack of grease.
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GAHorn
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by GAHorn »

The bolt called for is an AN7-20A... which is not drilled for a castle nut. (nor is the L19 bolt).
I'm not saying one is wrong to select that type nut... only mentioning the bolt for mx support. :wink:

The need for the all metal lock nut is subjective, in my opinion. The 0642105 L-19 eyebolt has a longer shank than the AN7-20A (likely because it's intended for an L19 mainspring which is thicker than the 170 mainspring) and that means a standard nylock nut or other standard nut will BOTTOM OUT and not torque properly without additional flat washer or two. Unless one checks the grip length of the bolt used.... ANY nut will appear loose.
'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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Seafeye
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by Seafeye »

Just ordered from Air Repair. $10.36
Scott Part Number 2341-3s
1950 Cessna 170A
N5793C
Serial 19837
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n2582d
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by n2582d »

gahorn wrote:Remember, that bolt should be torqued to <W R O N G - TORQUE previously listed in error>
Correction: A 7/16ths fine-thread bolt such as AN-7 should be torqued to 450-500 in/lbs.
For what it's worth the L-19 Maintenance Manual, TM 55-1510-202-20 C-1, Chapter 4, Section VI, paragraph 4-353, pg. 4-60A specifies a torque of 600-650 inch-pounds for L-19s not modified to the 2800-pound gross weight and 650-700 inch-pounds for L-19's which have been modified to the 2800 pound gross weight configuration. This is using a fiber insert MS21044LN7. I'd use an AN363-720 all steel locknut nut torqued to 650 in/lbs. Do not use a stainless steel nut. The paragraph I referenced above also calls for special washers.
Gary
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GAHorn
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by GAHorn »

n2582d wrote:
gahorn wrote:Remember, that bolt should be torqued to <W R O N G - TORQUE previously listed in error>
Correction: A 7/16ths fine-thread bolt such as AN-7 should be torqued to 450-500 in/lbs.
For what it's worth the L-19 Maintenance Manual, TM 55-1510-202-20 C-1, Chapter 4, Section VI, paragraph 4-353, pg. 4-60A specifies a torque of 600-650 inch-pounds for L-19s not modified to the 2800-pound gross weight and 650-700 inch-pounds for L-19's which have been modified to the 2800 pound gross weight configuration. This is using a fiber insert MS21044LN7. I'd use an AN363-720 all steel locknut nut torqued to 650 in/lbs. Do not use a stainless steel nut. The paragraph I referenced above also calls for special washers.
Gary, thank you. I notice however, that instruction is not relative to the eye-bolt PN 0642105 which is the subject of this thread. It appears to be with regard to a different bolt (as well as different washers) not specified in the illustration, which is accompanied by a seperate tie-down fixture. It's unfortunate the 100 Series Service Manual does not specifically address this sort of assembly-detail. The torque I listed previously came from that 100 Series torque-value-chart specification. I'm sure the 650 in-lb wouldn't be harmful for a 170 tho'.
'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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sfarringer
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Re: Tailwheel Assy ATTACH bolts/nuts

Post by sfarringer »

It occurs to me that the special washers could imply that the bolt may be a special high strength bolt with a radius under the head (which requires special countersunk washer).
However, I don't have any L-19 data to confirm or deny that possibility. Don't think I would increase torque unless I knew for sure what the bolt is.
Ragwing S/N 18073
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