Understand the importance of correct cg location,the aircraft is balanced with empty fuel tank,but once fueled up,that position changes,bringing cg further forward,as in my aircraft. does this sound right,and how do you compensate with a forward cg,during the early stages of the flight,does it make things unstable,etc,its not untill fuel is used that cg starts to come back to the correct position,later in flight.
Any explanations very welcome

Mark

The reason it's done that way is because the forward CG early in the flight is if anything MORE stable. Because of this you may find it a tiny bit unresponsive to the elevator, but that's about all.

On most trainers it makes no noticeable difference.

Steve

Nose heavy may be a little less responsive during the early part of the flight when the tank is full. It is better than having a model that is tailheavy and over-responsive when you are trying to land with an empty tank! Always a compromise, but you are generally better to balance with the tank empty.

Ross

Rear CG = unstable, snappy, hard to fly
Forward CG = more docile, less respocive, better stall characteristics.

basicaly Fwd CG is MUCH MUCH EASIER x 20 than tail heavy

And BTW, the difference in most cases is negligible

Eindecker:

1.- Always balance your planes with an empty tank, no questions ask!

2.-You asked a very smart question, It matter where the tank is located BUT trainers fly better nose heavy and at that point aerobatics are not in the envelope!

3.-when flying aerobatic planes in which you have the space, because of their size, then the tank goes on the c.g.

...so it is mainly a space issue!

Of course, if you move the tank very far from the engine, or don't position it's height properly, then you'll require a pump on the engine to get proper fuel flow.
Dennis-