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It is this out-of-balance condition that can cause a damaging flutter or buffeting of an aircraft and therefore must he eliminated. This is best accomplished by adding weights either inside or on the leading edge of the tabs, ailerons, or in the proper location on the balance panels. When this is done properly, a balanced condition exists and can be compared to the seesaw with a child sitting on the short end of the plank.

It is this out-of-balance condition that can cause a damaging flutter or buffeting of an aircraft and therefore must be eliminated. This is best accomplished by adding weights either inside or on the leading edge of the tabs, ailerons, or in the proper location on the balance panels.

In the context of aircraft design and maintenance, the terms counterweight and ballast generally have separate and different meanings. I will address each separately.

In the context of aircraft design and maintenance, the terms counterweight and ballast generally have separate and different meanings.

Both concepts involve mass used to balance, dampen, or adjust forces about a rotational axis. While ballast could also be described as a type of counterweight, it is best understood as working within the frame of reference of the entire aircraft since it adjusts the aircraft Center of Gravity (CG). Conversely, counterweights can be understood to work within a frame of reference that is smaller than the aircraft as a whole, such as an engine or a control surface.

I will address each separately.

Crankshaft Balance
Excessive vibration in an engine not only results in fatigue failure of the metal structures, but also causes the moving parts to wear rapidly. In some instances, excessive vibration is caused by a crankshaft which is not balanced. Crankshafts are balanced for static balance and dynamic balance. A crankshaft is statically balanced when the weight of the entire assembly of crankpins, crank cheeks, and counterweights is balanced around the axis of rotation. 'When testing the crankshaft for static balance, it is placed on two knife edges. If the shaft tends to turn toward any one position during the test, it is out of static balance. A crankshaft is dynamically balanced when all the forces created by crankshaft rotation and power impulses are balanced within themselves so that little or no vibration is produced when the engine is operating. To reduce vibration to a minimum during engine operation, dynamic dampers are incorporated on the crankshaft. A dynamic damper is merely a pendulum which is so fastened to the crankshaft that it is free to move in a small arc. It is incorporated in the counterweight assembly. Some crankshafts incorporate two or more of these assemblies, each being attached to a different crank cheek. The distance th~ pendulum moves and its vibrating frequency correspond to the frequency of the power irnpulses pf the engine. When the vibration frequency of the crankshaft occurs, the pendulum oscillates out of time with the crankshaft vibration, thus reducing vibration to a minimum.

Dynamic Dampers
The construction of the dynamic damper used in one engine consists of a movable slotted-steel counterweight attached to the crank cheek. Two spoolshaped steel pins extend into the slot and pass through oversized holes in the counterweight and crank cheek. he' difference in the diameter between the pins and the holes provides a pendulum effect.

Ballast provides a temporary or permanent change to overall aircraft center of gravity. Ballast might be included as a permanent part of an initial or modified design. When I was in flight training we used old aircraft tires filled with concrete as ballast to place the W&B of a U206G near a max gross weight and aft CG configuration for portions of mountain flying training.

Crankshaft Balance
Excessive vibration in an engine not only results in fatigue failure of the metal structures, but also causes the moving parts to wear rapidly. In some instances, excessive vibration is caused by a crankshaft which is not balanced. Crankshafts are balanced for static balance and dynamic balance. A crankshaft is statically balanced when the weight of the entire assembly of crankpins, crank cheeks, and counterweights is balanced around the axis of rotation. When testing the crankshaft for static balance, it is placed on two knife edges. If the shaft tends to turn toward any one position during the test, it is out of static balance. A crankshaft is dynamically balanced when all the forces created by crankshaft rotation and power impulses are balanced within themselves so that little or no vibration is produced when the engine is operating. To reduce vibration to a minimum during engine operation, dynamic dampers are incorporated on the crankshaft. A dynamic damper is merely a pendulum which is so fastened to the crankshaft that it is free to move in a small arc. It is incorporated in the counterweight assembly. Some crankshafts incorporate two or more of these assemblies, each being attached to a different crank cheek. The distance the pendulum moves and its vibrating frequency correspond to the frequency of the power irnpulses pf the engine. When the vibration frequency of the crankshaft occurs, the pendulum oscillates out of time with the crankshaft vibration, thus reducing vibration to a minimum.

Dynamic Dampers
The construction of the dynamic damper used in one engine consists of a movable slotted-steel counterweight attached to the crank cheek. Two spoolshaped steel pins extend into the slot and pass through oversized holes in the counterweight and crank cheek. The difference in the diameter between the pins and the holes provides a pendulum effect.

Ballast provides a temporary or permanent change to overall aircraft center of gravity. Ballast might be included as a permanent part of an initial or modified design. When I was in flight training we used old aircraft tires filled with concrete as ballast to place the W&B of a U206G near a max gross weight and aft CG configuration for portions of mountain flying training. I know glider pilots use ballast for adjusting aircraft CG as well.