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Heavy Wing

When I was test flying my Bearhawk I noticed that in level flight the right aileron was reflexed slightly more than the left. Very long story short, it turned out to be the result of a heavy wing, probably the 2 lbs of magnetometer and landing light in the left wing. It also showed up as a 12 lb higher weight on the left wheel at the W&B (a head scratcher), the result of my misplaced effort to minimize conduit runs.

Steady heading side slip

To fly wings level required a very small right roll input. This generated extra drag on the left aileron with an accompanying left yaw and what is referred to as a steady heading side slip. With wings level and ball centered, the aircraft would continually turn by a barely perceptible amount. With wings level and a constant heading the ball would be slightly out of center (the steady heading side slip).

The other frustration was that during early Phase One fuel would continually transfer (or draw unevenly) when in the BOTH position, in the direction of the ball. Initially some of this could be explained by my own efforts to keep the ball centered.


The symptoms in my case were:

  1. at the initial weight and balance one wheel weight was 12 lbs heavier than the other (heavy wing).

  2. slight roll input required to maintain wings level (increased aileron drag).

  3. one aileron reflexed higher than the other in wings level flight.

  4. with wings level, ball centered, the heading would very slowly change.

  5. with wings level, fixed heading, the ball would be slightly off center indicating a steady heading side-slip​​.

  6. when refueling it often took more fuel to fill one tank than the other. Fuel seemed to be either transferring between tanks, or burning more from one tank.


In hindsight I realized that a contributing factor was probably that I installed the magnetometer and landing light both in the left wing, to make use of the same cable conduit. The combined weight is around 2 lbs on a long arm. This also indicated a 12 lb higher weight on the left wheel (short arm) when we weighed the aircraft. It appears that the slight roll input required to counter the heavier wing was also creating a small but continuous yaw due to the increased aileron drag, resulting in the side slip condition.​


I installed washers under the "light" wing. Bearhawk owner and engineer Kevin Deuscher mentions HERE that using washers raise the hinge line reduces the camber of the wing.

Next, we adjusted the flap push-rods (acting as ailerons in the retracted position) to counter the slight tendency to roll left and managed to balance it out.

It took a while to resolve the issue, and the aircraft was then capable of flying with the ball centered, wings level.

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