As a general rule, must the cg of a tandem ultralight ( Re 500k-1,000k) be greater than 25% mean aerodynamic chord?
I understand the centre of pressure of a classic wing is at it's quarter point. It also produces a nose down moment, so that the cg and/or and horizontal tail moment need to offset this, or the plane will dive. To provide a nose up moment, the horizontal tail must produce a tail down force.
If you want a tandem airplane, you want the exact opposite.
So the to provide a nose up moment, I would imagine you want the cg always behind the Cp ( 25% MAC) of the wing, but in front of the plane neutral point, as you want to the tail to provide an offsetting tail up force,(nose down moment)
Is this correct?