RV-8 Tailwheel Steering Geometry

[RhinoDrvr]

I recently found quite a bit of wear in my Aviation Products tailwheel attach block with 1500 hours on it. This is allowing the fork a fair amount of fore and aft motion that I?d like to stop.

I called Karen and ordered the parts. My airplane currently has a 20 degree attach block installed (see photo attached) but this puts the top of the steering shaft forward of the fork...which I gather is less than ideal. I don?t get any tailwheel shimmy, but I can feel the wheel spinning around the instant I set the tail down until I get some weight on it.

API also offers a 10 degree unit, which would put the steering closer to the correct geometry, but I understand will make steering stiffer...I?m concerned about added wear to the steering system if that is the case.

What angle API blocks are you guys running with your chain setups?

https://photos.app.goo.gl/rzkZ1fGzNB62PX6e9

[smithflys23]

I?m interested to hear the responses you get.
My tail wheel sometimes spins when I set it down.

[scsmith]

How can it spin around? Isn't it locked with the pin to the steering arm?

[RV8JD]

May I suggest using the Bell TW fork with the Van's TW yoke, or the JDAir full bearing TW yoke and fork?

I (and many others) have used both and have been quite happy with them (with 6" solid tailwheels), especially the JDAir full bearing TW. Steers like buttah!

[scsmith]

I have an API fork that was made to fit into a standard Van's 'yoke'. (I think we need a better name for that part, like 'attach block').

Works just like a Bell fork.

[RhinoDrvr]

Maybe it?s not spinning all the way around, but there?s some definite feedback in the pedals that it?s not tracking straight at touchdown.

What is the geometry of your setup, Steve? Does the pivot shaft point forward or aft? Most RV?s I?ve seen have the top forward of the bottom, but from what I gather that is incorrect.

[RV8JD]

Originally Posted by scsmith

(I think we need a better name for that part, like 'attach block').

Just using the JDAir (and others) nomenclature.

[scsmith]

Originally Posted by RhinoDrvr

Maybe it?s not spinning all the way around, but there?s some definite feedback in the pedals that it?s not tracking straight at touchdown.

What is the geometry of your setup, Steve? Does the pivot shaft point forward or aft? Most RV?s I?ve seen have the top forward of the bottom, but from what I gather that is incorrect.

The top is slightly forward of the bottom. Standard Vans attachment block.

[RV8JD]

Below is a pic of the Bell TW fork in the Van's yoke. It gives an idea of the angle.

[skylor]

Originally Posted by scsmith

(I think we need a better name for that part, like 'attach block').

I have it on good authority that Van's internally refers to this part as the "po+ pipe" .

Skylor