The International Cessna^® 170 Association

We bought a used rudder to install on our 1952 170B. There was some alignment problems with the hinge points. I had to shim the upper bearing block out approx .150" so that the rudder would clear the top of the vertical. This did however give me a mismatch of approx .150" back from the L/E of the Rudder to the L/E of the vertical. I don't think this is to big of a deal, or is it? The next problem though is that the elevator torque rubs the rubber at where the torque tube goes through the cutout in the rudder. I don't get full travel of the rudder. I was planning on just trimming the skin back. There is plenty of edge distance to the fasteners at the front spar to do this. I had heard though that it may have been possible that elevator torque tubes on later model 170B were a small diameter than older ones is that a true statement. My torque tube is approx 2.5" in diameter. The 170B parts manual leads me to believe that 170B rudder and or elevator is interchangeable with any year 170B. The rudder we got is in perfect condition. It may have been reskined can't tell though. It just may be that a little trim to fit is in order. Any suggestion please help

If your 170 is in good working order, rudder installation is a simple proposition for your A & P. A couple of bolts at the top and middle, bushing, bearing, and bolt at the bottom and you're done.

If your A & P Mechanic is having problems installing your newly purchased rudder, I would suspect you have a defective part. You may want to return it and get your money back. Let the rest of the membership know where you purchased the rudder so we can all avoid purchasing misrepresented parts from your source. Keep this thred going so we can follow your progress. Regards, Dennis

Or the rudder is right and the plane is the problem, is there record in the books of rebuild. Even if there isn't look at it close to see if if was reworked.

I agree with mit. Check the vertical fin for modifications. There’s not a lot of clearance at the top to begin with. Two possibilities come to mind:

1. Was the vertical ever damaged/rebuilt?

2. Did your 170 ever have a VOR antenna installed in the vertical fin? If so, the top skin would have been removed in order to perform the installation and probably reattached with screws. The top skin should be flush with the top of the skins on the side of the vertical.

Regarding the elevator, yes it’s the same for all “B” models. What exactly is rubbing on the torque tube? Is it the bolts that join the two halves of the tube together? Again, another spot with not much clearance. The stops for the rudder should be able to prevent the rudder from hitting the torque tube. Is this problem the result of shimming out the bearing block? Do you have this problem without the shims for the bearing block? If you adjust the stops to eliminate hitting the torque tube and can’t get full rudder travel then it makes me wonder if something else is a problem.

The fact that you are having these clearance problems and can’t solve them without creating another problem makes me wonder if there’s been some sort of damage/rebuild in the past.

You said this is a replacement rudder. Where’s the “old” one? Did that one fit ok? Any clearance problems? Can you compare the “new” one to the “old” one and find any differences? That might help determine where the real problem lies.

It's hard to offer solutions without seeing it first hand.

If pictures of a completely dissassembled rudder would help, let me know. I have both upper and lower skins off, and can take pics of the parts that have to be aligned to provide clearence. Have been worried about the very experience you are having, I used my old skins to duplicate the location of the rivit holes in the new skins. Where the #0333132 Front Spar joins the #0533000-10 Tip Assembly is a critical angle.

Before riviting begins, while it is all clecoed together I plan on mounting it to the airplane to check for fit.

If photos would help, I can email them to you, or, get help to post them here - have not done that before.

I disassembled a 140 fin not too long ago that appeared to be a non-cessna replacement. Univair or Spruce perhaps, and the short front vertical spar had all the holes in it drilled 1/4" high. The net effect was that the forward end of the fin skin had to be trimmed up 1/4" so the spar could reach down far enough so the mounting bolt hole would line up with the bolt hole in the bulkhead. Holding that spar up against a factory spar it was easy to see it was the right size and shape but the holes were off quite a bit. If you have the old parts, it'd be interesting to compare them against the replacement parts and see how close they match. Could be the replacement you have is not quite to spec, or perhaps the fin is not quite to spec. Or maybe it's something else altogether.

N1478D wrote:If pictures of a completely dissassembled rudder would help, let me know. I have both upper and lower skins off, and can take pics of the parts that have to be aligned to provide clearence. Have been worried about the very experience you are having, I used my old skins to duplicate the location of the rivit holes in the new skins. Where the #0333132 Front Spar joins the #0533000-10 Tip Assembly is a critical angle.

Before riviting begins, while it is all clecoed together I plan on mounting it to the airplane to check for fit.

If photos would help, I can email them to you, or, get help to post them here - have not done that before.

Hey Joe! Been missin' you here! Glad to see you're back online!