mass flywheel

The mass of the flywheel depends on the motor and the mass of the car.
The calculation of the mass is a part of the engine. A lot of people doing flywheel-tuning. They take weight off the flywheel, the mass declines and the car becomes a little faster?

If the mass declines too much, you will never be able to drive the car.

flywheel - bolts

The main function of the flywheel is keep the motor spinning. It has a weight of 12 kilo. The total weight of the clutch (housing inclusive) is about 19,5kg...

Such a mass will cause a lot of centrifugal force. First a calculation of myself followed by a comparison with the real information.

What's the radius of a bolf if you can use 8?

The centrifugal force is calculated in the mass center. If you count the whole flywheel the mass center is in de middle. If there are 8 bolts, you can devide the flywheel in 8 equal parts. The distance from the center to de mass center is about 200mm.

F(c) = 14 808N (for 1 bolt)

The torque causes a force perpendicular to the radius: F(t) = 1280N

F(tot) = 14 863N

The max shear of a 12.9 bolt is 1080Mpa. (www.werktuigbouw.nl)

the safety factor for dynamic loads: v= 3...6

for the calculation: v=5

result: r= 4,68

this results in 8 bolts: ISO 4017 - M10 - 12.9

If you use bolts with another classe, you will become a larger radius.

more info: tabellenboekje voor metaaltechniek