✈️ CG (Center of Gravity)
A plane's balance point — getting CG right is one of the most critical setup steps for stable, safe flight; too far back is dangerously twitchy.
What it actually does
Centre of gravity is the balance point of an aircraft, and it is the most safety-critical number in flying. An aircraft balanced too far back is unstable and can be genuinely uncontrollable; too far forward and it is nose-heavy and will not climb well but is at least predictable.
In practice
Manufacturers publish a CG position, normally measured back from the wing's leading edge. Check it with the aircraft ready to fly, battery installed, using your fingers or a balancing stand. Move the battery to adjust before adding any ballast.
Worth knowing
Check CG before every maiden and after any change to battery size or position. If in doubt, err slightly nose-heavy — that direction flies safely, the other does not.