Rudder horn slanted down

[Bobbyt]

Hello:
I noticed a few Piets have the rudder horns slanted down slightly inline with the cables (like the elevator horns slanted inward inline with the cables). I see no problem with the elevator horns because they cancel each other out aerodynamically, but the rudder horn slanted down may act like trimming the nose up. Has anyone slanted their rudder horn down slightly in this way? I did and now I think I shouldn’t have. Any benefit/problem?

Thanks!

[taildrags]

Not sure I've seen that done. My horn is flat and perpendicular to the rudder, no bends.

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

[Richard Roller]

I'm not sure what you are referring to. Any pictures?

[taildrags]

Richard, sitting in the cockpit, turn around and look straight back at the leading edge of the rudder and the horn back there. Get two large Crescent wrenches and slip each of them over the leading edge of each half of the horn and push down so as to bend the leading edges of the horn down into the airstream instead of straight into it. What you end up with is getting the horns a bit more into alignment with the direction of pull of the rudder cables but also something that will add just a bit of tail-down (nose-up) trim. In the case of my plane, which has a 16 gallon nose tank, after I fuel up and go flying, for about the first hour or two until some fuel burns off, I have to hold some back-stick or the plane wants to dive. Having a bit of nose-up trim would be useful to me, but many Piets are tail-heavy and adding more nose-up trim would only make things worse. So in general, I don't think bending the rudder horn is a good way to improve anything.

-Oscar

[Rob]

I twisted just my ends a little for better alignment. Not the whole horn.

[Bobbyt]

Yes, I see, and many thanks. This is a nice solution without bending the entire horn!

[Bobbyt]

And I also want to add (Oscar), I have purchased a second hand Pietenpol nose fuel tank with an 18 gal capacity (and will use an o-200 engine), so plenty of weight up there. Using your logic, maybe having the rudder horns tilted down inline with the rudder cables and thus adding nose up trim may not be all that bad of an idea. But I just want to hear the fellow’s input before making the horn position permanent. Gracias—all!

[danoliver]

If you look real close at drawing number seven then it appears to be slanted down. Of course drawing 2 shows the thing being put in straight. And in pictures of the last original it looks straight.
I went and did mine tilted down and aimed it right for the rudder bar. Then later I realized that the cables should probably run under the seat. Which meant I didn't quite tilt it down enough but it was already done. So what I wound up with was it being tilted somewhat down. Seems to be working and so far I haven't wanted for any nose down trim but I'm sure there's a zillion other factors that go into that.

[Bobbyt]

Yes, that’s what I’m talking about! I’ve seen this and wondered if there was any adverse trim. You answered my question perfectly!