Rudder Balance

[boydkl]

We have replaced my rudder control horn with the univar replacement part.
What is the expected Cessna balance value for a 1951 C170 A (N23AD)?

Thanks

[Bruce Fenstermacher]

I may be having a brain fart but I'm pretty sure the rudder isn't balanced.

[GAHorn]

The rudder has a balance weight of 4.0 lbs. (+.12, -0) and a moment of +23 to +27 in.lbs. Same for both 170A and B aircraft.

(The ragwing is slightly different variance on the wt. ...4.0 lbs (+.25, -0). Same moment.

[boydkl]

Yep, it is a control surface and balance must be checked after repair.
Thank you George.
I used a 2 lb diving weight and measured 12 & 7/8 inch to balance. Just under 26 in lb.

[Kyle Wolfe]

Air Dog, I don't have my service manual at home, but how did you know how to balance that? Just curious as I had a rudder recently re-skinned and reinstalled. I've not yet talked to my IA, but am wondering what's involved....

[Bruce Fenstermacher]

Yep, it is a control surface and balance must be checked after repair.

More correctly it is a balanced control surface. Not all control surfaces are balanced.

Guess I was having a brain fart with my first post huh.

[GAHorn]

As the frequency of mine has increased lately, ...I'm just glad they don't smell.

[spduffee]

The rudder has a balance weight of 4.0 lbs. (+.12, -0) and a moment of +23 to +27 in.lbs. Same for both 170A and B aircraft.

(The ragwing is slightly different variance on the wt. ...4.0 lbs (+.25, -0). Same moment.

Hey George,
Can please you help me find the specs you mention in the (2008) thread above? I have heard both sides: The 1950 170-A only has balanced ailerons, or better said, there are no other balance values published for anything but the ailerons. If they are published for the rudder, elevator and aileron, I need them quickly so I can get this plane up and running.
Thank you!

[Bruce Fenstermacher]

All the the control surface balance procedures and specs for our 170s as well as others are in SLN 86-44 which can be found in our library and downloaded.

24 minutes question to answer. Is that quick enough?

[spduffee]

Almost as fast as Google's response time...awesome!
Thanks Bruce!

[N2613V]

I recently had to repair my rudder and after searching for Cessna Data on the balancing I located a the attached document prepared by Parts/MX coordinator, Tom Hall. I spoke with Tom and he advised that according to Cessna the balance on the rudder is not critical due to low speeds and the fact that it is vertical and gravity does not have any significant effect.

Hope this is of some help.
Mike

Moderator: Here is a link to the file Mike shared attached to the first post: http://www.cessna170.org/forums/viewtop ... =41&t=8196

Aircraft which do not exceed 160 mph do not ordinarily experience "flutter", but the position of the control surface has little bearing on the matter. Rudders "flutter" as effectively as do other surfaces.

Just this last week I sent the document mentioned to a former member in AK who found his rudder out of spec. He and I both agreed that just because it is out of spec is no reason not to put it within the specification.