flipped rib

How to keep the Cessna 170 flying and airworthy.

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Buckeyejim
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flipped rib

Post by Buckeyejim »

I noticed something peculiar in my B model the other day. Some of the end ribs in the
flaps and ailerons seem to be flipped (I think 2 or 3 of the 8 were that way).

That is, instead of the vertical surface lining up with the end of the flap or aileron skin,
it was half an inch or so inside. This must have been caused by the factory installing the rib
180 degrees from normal ( hard to explain). Apparently Rosie the Riveter slipped up, and
if an inspector caught it he decided it wasn’t worth the bother to correct.

Does anyone else’s plane have this condition – has it been discussed in the forum?
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GAHorn
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Re: flipped rib

Post by GAHorn »

How can you be certain it's "factory"? Lots of repairs are simply not logged (unfortunately and illegally.)
'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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c170b53
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Re: flipped rib

Post by c170b53 »

C7AC3E84-B082-4547-91E0-648564B22102.jpeg
I reskinned my flaps, but it’s been awhile, but I don’t quite understand because the flap profile would be all wrong.
Oh ( after uploading the photo) and rereading you message, oh again :D
O.k. I think I understand now, those ribs do not go to the end of the flap there’s a gap as you can see in the photo. You start riveting at the front row across the flap and then work aft by row across the flap with your last skin. You need to fashion a small bucking bar on a stick, to get the last rivet row. I used the bulb method to reinforce the trailing edge.
Hope I understand correctly your concern
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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n2582d
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Re: flipped rib

Post by n2582d »

Jim,
The way I read the problem is that some end ribs have the flanges exposed rather than facing in on the ailerons and flaps. I can see how this would be possible on the ailerons but without shortening the flap spar I don’t see how this can be done on the flaps. If one swapped the position of p/n 0523912 and 0523912-1, the flap end ribs, you would either need longer skins or a shorter spar.
5D93212C-8363-48CD-A5E3-81ABDA9F4CED.jpeg
To have the end rib flanges exposed on the ailerons swap the respective ribs between the right and left aileron.
Gary
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c170b53
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Re: flipped rib

Post by c170b53 »

(You tube link was hacked-therefore, deleted by moderator)
Darn, what I really meant was ( :wink:) oh-oh-oh-oh (song)
:wink: Again
Last edited by c170b53 on Sat Oct 13, 2018 8:43 pm, edited 1 time in total.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
Buckeyejim
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Re: flipped rib

Post by Buckeyejim »

I looked again today and paid more attention. My plane has just two "flipped ribs" : outboard end of left aileron and
inboard end of the right one. I suppose it could have been a botched repair, but both ailerons look factory to me, and
my mechanic agrees. I'm not really worried about it - just wondered if other planes have this condition or is mine unique?
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n2582d
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Re: flipped rib

Post by n2582d »

Jim,
My ailerons ribs are oriented as your are. Mine have one lightening hole in each of the outboard ribs. I have a NOS right outboard rib (0523811-1) that doesn't have the hole.
P/n 0523811-1
P/n 0523811-1
I see that the early 172 IPC has the part numbers reversed from what the 170 IPC shows. C-172 IPC left outboard rib is p/n 0523811-1 which is the same p/n for C-170B right outboard rib. C-172 right outboard rib is p/n 0523811 which is the same p/n for the C-170B left outboard rib. I think that the 170 IPC is correct.

In order to gain back the 0.001 mph you are losing with those ribs facing the wrong way and having lightening holes you will want to install p/n 0721107-1 and 0721107-2 to the outboard wing rib inboard trailing edge. :wink: It’s found on the early 172’s, the C-150 and probably other models.
p/n 0721107-1
p/n 0721107-1
c-172 wingtip fairing
c-172 wingtip fairing
Fairing.jpg (14.96 KiB) Viewed 22605 times
Gary
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c170b53
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Re: flipped rib

Post by c170b53 »

Gary all I can say is I hope the FBI is unaware of your sleuthing talents.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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n2582d
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Re: flipped rib

Post by n2582d »

Jim,
I'm guessing the FBI isn't too concerned about the orientation of Cessna aileron ribs! J. Edgar Hoover's orientation is a lot more ... “riveting”! :twisted:

I think the FBI may need to focus on BuckeyeJim, not me! Until he brought it up I never noticed that the ailerons had some end flanges exposed and some turned in. In looking further into this, on mine at least, all the aileron rib flanges on both ailerons are on the left side of the rib except for the center rib on the right aileron. I'm very curious if there are others out there have ailerons with the outer rib flanges exposed. From a manufacturing standpoint it makes it a lot easier to build the aileron with the last rib flange exposed. No bucking needed -- just squeeze the exposed rivets.

While I know that the IPC is not a guide as to how Cessna put together their airplane, it is interesting to see the differences between the C-170A, C-170B, and all C-172 left aileron end ribs. Note the differences in exposed flange and lightening holes. The 170B and the 172 share the same part numbers. The 170A IPC doesn't breakdown the aileron assembly but the aileron itself has the same part number as the 170B. BuckeyeJim, could it be that our ailerons came off of C-170A's? What do the rest of you have for end ribs on your ailerons?
C-170A
C-170A
C-170A.png (15.18 KiB) Viewed 22502 times
C-170B
C-170B
170B.jpg (29.42 KiB) Viewed 22502 times
C-172
C-172
C-172.jpg (20.67 KiB) Viewed 22502 times
Last edited by n2582d on Mon Oct 15, 2018 9:52 pm, edited 1 time in total.
Gary
Buckeyejim
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Re: flipped rib

Post by Buckeyejim »

Interesting the things we can discuss in this forum! As for J Edgar, one thing's for sure - he really knew how to hang onto his job.

I doubt if my ailerons came from a 170A, as my serial number is 25174, not an early '52. I'm hoping other members will be checking
their aileron rib orientation to confirm. Gary's explanation that the ribs were installed that way for ease of manufacturing makes more
sense than my thought that Rosie the Riveter screwed up.
Buckeyejim
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Re: flipped rib

Post by Buckeyejim »

Over a thousand views and so far Gary is the only one who has responded about
the orientation of his aileron end ribs. It’s really no big deal, but I’d think somebody
else would have checked out his aileron ribs by now and responded as to whether or not
theirs are the same. That would confirm (or deny) that that orientation was standard
Cessna factory assembly procedure.
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lowNslow
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Re: flipped rib

Post by lowNslow »

It might help if you posted a photo and show us exactly what you are talking about and how it looks.
Karl
'53 170B N3158B SN:25400
ASW-20BL
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c170b53
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Re: flipped rib

Post by c170b53 »

I think Gary nailed it, so sorry Jim, I thought this topic had reached an end.... :oops: but if it helps any all my surfaces have their caps rivited flanges inboard to the surfaces, ends flush
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
Buckeyejim
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Re: flipped rib

Post by Buckeyejim »

Rt aileron outboard end.JPG
Karl's suggestion to post pictures was a good one. Unfortunately I'm not much of a photographer, as you can see.
But hopefully the two pics are good enough that you can see the difference.
Rt aileron inboard end.JPG
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Bruce Fenstermacher
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Re: flipped rib

Post by Bruce Fenstermacher »

OH, now I see what all the flap is about :lol:

OK, in the first post you stated you have a 170B. You actually have a '50 170A serial 19433. So the aileron with a smooth end is not correct according the the IPC illustration. I think because of your typo we were all thinking the other way around.

At first I thought maybe your "B" was a built on the cusp between A and B production and there was some mixing of ribs or finished assemblies from the A on the B. But your A is no where near the cusp.

I'd venture you may have a B aileron repair on your A. I don't know if the entire assembly of a B would be right for an A though so that would have to be answered.
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