Why is the mass of a flywheel concentrated at its rims ?
When the mass is concentrated at the ends of the flywheel, it helps to increase the moment of inertia, due to this once it is opreated , it takes time to come to rest even when the force is not supplied.
Theoretically, the more mass you can put toward the rim the more energy you can store for a given RPM. However, most manual transmission flywheels are made from castings, often need a balance weight, and need to absorb heat from the clutch. For those reasons the center part of the flywheel is still fairly thick. Most manual transmission engineers would like to have more mass in the flywheel because that dampens the engine vibrations which reduces gear noises and absorbs more heat to help the clutch last longer. Of course, that adds weight to the car, takes up more space, and reduces the engine response so, like so many things in life, the thickness of the flywheel is always a compromise. A conventional automatic transmission “flywheel” isn’t really a flywheel in the usual sense of the word; it’s just something to attach the converter to the crankshaft and to hold the ring gear for the starter.
When the mass is concentrated at the ends of the flywheel, it helps to increase the moment of inertia, due to this once it is opreated , it takes time to come to rest even when the force is not supplied.
Theoretically, the more mass you can put toward the rim the more energy you can store for a given RPM. However, most manual transmission flywheels are made from castings, often need a balance weight, and need to absorb heat from the clutch. For those reasons the center part of the flywheel is still fairly thick. Most manual transmission engineers would like to have more mass in the flywheel because that dampens the engine vibrations which reduces gear noises and absorbs more heat to help the clutch last longer. Of course, that adds weight to the car, takes up more space, and reduces the engine response so, like so many things in life, the thickness of the flywheel is always a compromise. A conventional automatic transmission “flywheel” isn’t really a flywheel in the usual sense of the word; it’s just something to attach the converter to the crankshaft and to hold the ring gear for the starter.
