Sorry, but the problem is still not resolved... because one still has a problem:
it never takes off

banktoturn has indeed some points here.
As far as a flyable aircraft is concerned the CG location does affect how the aircraft reacts to the pilot's controls even if the influence maybe more or less critical depending on the actual speed and wing loading.

A tail-heavy aircraft will be more unstable and susceptible to stall at low speed
e. g. during the landing approach.
Whereas a nose-heavy aircraft will be more difficult to takeoff from the ground and to
gain altitude and will tend to drop its nose when the throttle is reduced. It also
requires higher speed to land.

In order to achieve a good longitudinal stability, the CG should be ahead of the
Neutral Point (NP), which is the Aerodynamic Centre of the whole aircraft.
NP is the position through which all the net lift increments act for a change in
angle of attack.