JRFisher

Is the purpose of an elevator counterbalance just to assist the servo, or does it increase the elevator's efficiency, or both?

DMcQuinn

My Feedback: (13)

The area in front of the hinge line assists the servo. The affect of the surface is a function of total square inches, so compared to the same surface without the counterbalance, it should be more effective.

Rodney

Which counterbalance are you talking about, aerodynamic or static. Aerodynamic is when some of the surface area is in front of the hinge line while static balance is just weight added in front of the hinge line so that there is equal weight in front of and aft of the hinge line. If it is the former "aerodynamic" then this helps take some of the load off the servo during manuevers. Just be careful as to how much area is in front of the hinge line, more than 10% can lead to some big problems, usually the inability to find a neautral setting resulting the airplane constantly galloping or porpoising. You can combine both types by weighting the area forward of the hinge line for static balance as well and get the best of both worlds. The static balance help in negating any effects of acceleration normal to the hinge line.

JohnW

My Feedback: (6)

What rodney said, with a note on mass balancing. Models almost never have mass balancers, but will commonly have aerodynamic balancers (the part that sticks forward of the wing line.) I don't think they affect efficency much, other than you have more movable control surface area compared to an identical setup without the forward bits. The do however reduce servo loading and on some setups they help reduce control surface flexing. Mass balance is adding weight in front of the hing line to balance the control surface, which is common in many full scale applications. However, this is not needed in the model world as the mass inertia can actually casue flutter due to the less ridged materials used in models.