15. A four stroke oil engine developing 75 kW at 300r.p.m is to have the total fluctuation of speed limited
to 5%. Two identical flywheels are to be designed. The workdoneduring the power stroke is found to
be 1.3 times the average workdone during the whole cycle. Theturning moment diagram can be
approximated as a triangle during the power stroke. Assume that thehoop stress in the flywheel and
the bending stress in the arms should not exceed 25 MPa. The shearstress in the key and shaft
material should not exceed 40 MPa. Give a complete design of theflywheel. Assume four arms of
elliptical cross-section with the ratio of axes 1 : 2. Designshould necessarily include (i) moment of
inertia of the flywheel, (ii) flywheel rim dimensions, (iii) armdimensions, and (iv) flywheel boss and
key dimensions and sketch showing two views of the flywheel withall the dimensions
