It has recently come to my attention that the rudder horn drawing in the Aviat S-1S plans is not correct. I may have known this before now but for some reason it didn't trigger any memories for me. They reference the S-2 part number in the plans but there's also a detailed drawing of the part. That's great, sometimes they don't do that for the S-1 builders....well,,, it would be great of the drawing was correct. Since the factory just used the S-2 parts bin to build S-1 rudders it was not important or even known that the S-1 drawing was not updated to match the S-2 drawing.
I've been helping a forum member offline with his S-1 build/rebuild and in the course of building a new rudder he found the horn hit the tailpost well before he got full travel. I had modeled all this in SWx but I had yet to notice that the same problem was present there. I was able to confirm that if you build the horn based on the drawing you will find the horn hits the tailpost at around 23°. The rigging specs call for 30° +/-2° for the rudder travel. I looked at the horn on the S-2A and it is a very different geometry compared to the S-1 drawing. My deflections seem to be about 33° in both directions on the S-2A -- in fact the rudder will lightly touch the elevator at full deflection with a little gentle pressure to simulate a reverse airflow.
Below is a drawing that reflects the S-2 geometry and will result in the horn hitting the rudder stop before it touches the tailpost.......
I've been helping a forum member offline with his S-1 build/rebuild and in the course of building a new rudder he found the horn hit the tailpost well before he got full travel. I had modeled all this in SWx but I had yet to notice that the same problem was present there. I was able to confirm that if you build the horn based on the drawing you will find the horn hits the tailpost at around 23°. The rigging specs call for 30° +/-2° for the rudder travel. I looked at the horn on the S-2A and it is a very different geometry compared to the S-1 drawing. My deflections seem to be about 33° in both directions on the S-2A -- in fact the rudder will lightly touch the elevator at full deflection with a little gentle pressure to simulate a reverse airflow.
Below is a drawing that reflects the S-2 geometry and will result in the horn hitting the rudder stop before it touches the tailpost.......
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