Staggerwing C.G.

[Don Cooper]

I am getting ready to start on an IPS-powered Beech Staggerwing from plans I downloaded. Unfortunately, the plans don't show a C.G. location and I am not sure how to factor in the stagger in locating the C.G. Any suggestions for a starting point? I plan to use an undecambered airfoil with (per Profili) a relatively high negative moment.

[Dave Robelen]

Hi Don,
That is a very common issue. It makes no difference whether the stagger is positive or negative. First, select a balance point you would use on one wing as if it were a monoplane (35%?). Then do this for the second wing. Draw a sloping line between the wings. Halfway between the wings on this line would be a good starting point.
Regards, Dave

[Don Cooper]

Dave,

Thanks for the info.

Don C.

[Rodney]

Another easy way on any bipe is to look down on it from directly overhead. Now place the CG 25% of the way back between the leading edge of the most forward wing to the trailing edge of the most aft wing. This applies to wings of equal area only of course. If one wing has suffidently more area than the other, you have adust accordingly.