- The turning moment diagram for a petrol engine is drawn to the following scales of 1 mm = 80 N-m and 1 mm = 5.5°.The areas between the output torque curve and the mean resistance line of a turning moment diagram for a multicylinder engine, taken in order from one end are as follows: + 310,
– 650, + 100, – 335, + 885, – 310, mm2. The engine speed is 900 r.p.m. and the fluctuation in speed is not to exceed 2% of the mean speed. Find the mass and cross-section of the flywheel rim having 774 mm mean diameter. The density of the material of the flywheel may be taken as 7800 kg / m3. The rim is rectangular with the width 4 times the thickness. Neglect effect of arms, etc.