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A number of pilots have commented on the Bearhawks yaw sensitivity. It is a frequent topic of discussion anytime another pilot flies with me. Yaw sensitivity may contribute to uncoordinated flight (ball not centered), which can in turn effect the way the fuel system feeds from each tank.
Rudder
It is common for taildragger aircraft to have large rudder surfaces to provide good rudder authority at slow speeds, to aid ground handling and increase the ability to easily sideslip. As a result of having powerful rudder authority at low speeds, some also exhibit a higher degree of yaw sensitivity at cruise speeds. The Bearhawk rudder tends to be remarkably powerful, and maintaining balanced flight may initially take some practice.
In addition, there may be some variation in the engine cowling size (profile) as a result of different propeller spacing from the CG datum being different from the original design. This may also affect yaw stability.
Center of Gravity
Yaw sensitivity is more pronounced at aft CG, and more stable at forward CG.
Design
The vertical fin is slightly offset to compensate for the asymmetric blade effect from a clockwise rotating propeller (when viewed from behind). Most aircraft have the rudder trimmed permanently with a small fixed tab to provide balanced flight at cruise speed.
If flying at a speed slower than normal cruise speed it requires slight right rudder input, and at a speed above trimmed cruise speed it requires slight left rudder input to keep the ball centered.
Effect of Yaw on the fuel system
The effect of yaw on the fuel system is discussed in detail under the article on Fuel System and Fuel Management HERE.