Conduct the following analysis for 2 full revolutions of the crankshaft for the
3-cylinder radial engine shown with dimensions on the following pages:
1) The velocity and acceleration of each piston in the xy-plane with respect to the angle of crank #1.
2) Develop a lumped parameter model of a single slider/crank mechanism, accounting for the mass
of the crank, connecting rod, and piston. Generate the table of known parameters with respect to
crank angle #1.
3) The rotating out-of-balance forces due to the motion of the crank and connecting rod, and the
reciprocating out-of-balance forces due to the motion of the connecting rod and piston for a single
slider/crank mechanism from the shown engine.
HINT: Use the concept of dynamically equivalent masses.
4) The total rotating and reciprocating out-of-balance forces experienced by the engine, present ALL
of the following plots with respect to crank angle #1:
a. The total rotating out-of-balance force.
b. The total primary reciprocating out-of-balance force.
c. The total secondary reciprocating out-of-balance force.
d. The total combined out-of-balance force (summation of parts (a), (b) and (c)).
Note the following assumptions:
• The engine is operating under state-state conditions with a constant angular velocity of the crank
of 5300 rpm
• Neglect the influence of static weight
• Use the ‘fast’ approximation for the acceleration of the reciprocating masses.
• mpiston = 0.4 kg, mcrank = 2.0 kg, mrod = 1.2 kg
• lcrank = 60 mm, lrod = 180 mm
• the radius of gyration, kG, of the connecting rod is approximately 84.85 mm
• The crank and connecting rod can be treated as slender rods, and the piston as a point mass