Originally Posted by egrave1
When the airplane CG says 31/2" to 41/2" what does it make the airplane do I still have to balance it at both 31/2 and 41/2 I would think that 41/2 would make the airplane noes heavy
The further back the CG is located, the more unstable the model will be. To far back toward the tail, and your model will not be controllable.
And, to far forward, and you might not be able to pull the nose up during a landing. So, the location between the suggestions by the mfg should be fairly safe. Adjust either forward or rearward to suit your flying preferences.
As for me, I just put the CG per the mfg recommendations, and go fly.
Some folks out there fly the model up high, then while reducing power, put the model in a dive while returning the elevator to neutral. If the model continues straight, the CG is pretty much neutral. If the model pulls out, this is a sign of being nose heavy. If it tucks under, look out!
This would be for an acrobatic model. It would be of less usefulness for a Piper Cub type of model.