Ball off center in straight and level cruise

[chrispratt]

If you find it is rigging, Cleaveland Tools (http://www.cleavelandtool.com/RUDDER.../#.WcBQKa3Mz64) has a plastic rudder tab you can try. Fly it and trim as necessary. Then paint and attach with 3M weather strip glue or similar. Mine has been on for 12 years now.

Chris

[Kyle Boatright]

Balsa wedge plus monokote plus proseal was my recipe. It has been fine for 16 years.

[PilotjohnS]

Could an airplane every be flying sideways( fuselage no aligned with airflow) and the wings level and the ball centered?

I was thinking of mis rigged flaps/ailerons such that a slight forward slip is required to maintain wings level. Would the ball be in the center then?

[lndwarrior]

Originally Posted by chrispratt

If you find it is rigging, Cleaveland Tools (http://www.cleavelandtool.com/RUDDER.../#.WcBQKa3Mz64) has a plastic rudder tab you can try. Fly it and trim as necessary. Then paint and attach with 3M weather strip glue or similar. Mine has been on for 12 years now.

Chris

Great suggestion! Thanks!

[BobTurner]

Originally Posted by PilotjohnS

Could an airplane every be flying sideways( fuselage no aligned with airflow) and the wings level and the ball centered?

Yes. Easy to demo in a twin with one engine feathered. The large rudder force violates the approximation that rudder torque is important, but rudder force is negligible.

I was thinking of mis rigged flaps/ailerons such that a slight forward slip is required to maintain wings level. Would the ball be in the center then?

I don't think so.

[Climb3zero]

Interesting video where Darryl Greenamyer sais his plane (Rare Bear) flies sideways too! Go to the 14 minute mark to hear the statement or watch the whole video as it is very interesting.

https://www.youtube.com/watch?v=Hu6degk7rh8

Ed Soderblom
RV8

[chrispratt]

Originally Posted by lndwarrior

Great suggestion! Thanks!

If you use this piece, you can temporarily attach to the rudder using some of the aluminum tape like you use inside the cowling. It will hold but comes off easily when you need to adjust it. Fly the plane. Then trim the tab length as needed. I think I eventually took about an inch off mine before I got the ball centered at cruise. Depends on where you mount the tab. Obviously always mount in the same place during flight trials.

I suggest buying two pieces, one for test and then one for final mount in case you find you've trimmed off too much and the ball goes the other way.

Focus on getting it right for cruise flight as rudder trim will change for other speed regimes.

Good luck.

Chris

[RV7Guy]

I used a 4" tall piece of aluminum with 1" hanging off the back of the rudder. The bottom of the tab was in approximately alignment equal to the top of the Horizontal stabilizer. The tab was riveted and pro sealed on.

I trimmed for cruise flight power settings since the plane was for long CC flights!! It took me two flight to get needed setting. On climbs and descents you have to fly the rudder but that becomes instinctive.

I should point out, that the plane exhibited the same characteristics without the wheel pants and fairings. After install the same trim was required so I must have got the them installed correctly.

The wedge works well too. Just a matter of aesthetics and personal preference.

[Raymo]

Originally Posted by brad walton

Mine is off a half ball to the right in cruise configuration. In climb more, and in descent it requires left rudder. So in cruise, I maintain a little right rudder pressure. No problem. And if I cruise with no pressure on the rudder peddles and the ball is out by a half, there is no discernable change in airspeed. My opinion, don't worry about it. You are going to be on the rudder peddles most of the time anyway.

Mine is exactly the same. I plan to re-check everything and install a wedge as needed. Can't stand the ball being off center even with no speed penalty

[hohocc]

Is the ball indicating correctly? There are plenty out there that don't, both glass and steam.
Glider pilots tape a short length of wool to the centre of the canopy which will follow the path of the air. Not sure how the propwash would affect that indication but I can't think of a cheaper or easier thing to try just to confirm the ball is correct.