Sorry if this is a dumb question, but why do the instructions on the planes I have put together so far specify balencing for the center of gravity with an empty fuel tank? I know that the plane will be easier to handle in the air nose heavy (ie with fuel in the tanks) but lets say 99% of the time I land under power (fuel remaining) then wouldn't it be better to set the CG with a little fuel in the tanks for a good balence on landing (actually, why not slightly tail heavy on landing with a taildragger)?

Adam

You always balance with the CG at the WORST it could get durring flight. With a typical trainer, the worst is with an empty tank.

Definition of worst CG (for this discussion) is the CG where you have the least possiblility of maintaining control of the aircraft. If the CG is allowed to get too far back, then the aircraft can become virtually uncontrollable.

Because you can get carried away with having fun flying the model, and might not always land with fuel in the tank, you need to balance models that have the fuel tank ahead of the CG with the tank full. If the fuel tank was behind the CG (and it can be in some pusher type models) then you would balance with it full.

Precision aerobatic models will often have the fuel tank centered on the CG to make it so the airplane responds the same no matter how much fuel is left.

You don't balance a plane differently based on what type landing gear it has. The wheels only matter when they are touching the ground.

The only exception I will make is if the engine/tank is in the rear of the plane, you then want to balance it with a full tank because this is the worse case condition.

That way the C of G won't move to far back if you empty the tank in the air. This could cause unstable flight conditions.

Jetts