Found an interesting thing on the rudder from a 54 170B I am replacing the bottom skins of, prior to painting. Wondering if this is a sanctioned beef up installed poorly or something else.
While giving the rudder the once over I noticed some rivets missing in a tab where it looked like there should be some. There is a 'C' channel that runs from the top of the rear spar (0333115) diagonally to near the top of the front spar (0333132) ending just below the tip rib (0333113) When I put pressure against this channel you could hear its tab chaff against the rear spar top. That is where it looks like there should be some rivets to attach the two together. I went to look at another rudder I have and it does not have that 'C' channel at all. Looking at the IPC, it also does not show that channel.
What I am wondering is if there was any Service Bulletin or like publication calling for a reinforcement channel to be installed in that location. It looks like a logical place. Anyone have any words of wisdom. Thanks for your input. Brian
I have both uppers and both lowers off of my rudder at the current time. The inside of the rudder looks exactly like Figure 15 - Rudder Assembly on page 24 of the 170A IPC. For the upper skins there in an interior Auxiliary Spar (15-10). Both uppers and lowers are rivited to the Rib - Rudder Lower ( 15-21). And, in the lower part of the rudder there is the Rib - #1 Rudder (15-24) that you would be able to both look up from the bottom and see and feel. This rib is attached to the Reinforcement - #1 Rudder Rib and makes the Rib Assembly - #1 Rudder which the Bellcrank is attached to. The Rib - #1 Rudder (15-24) is made with an upwards angle to it and might be what you are describing.
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