Q1-1

An air compressor has a crank arrangement similar to that shown in Fig. 1-1. The stroke is 4 in., and the length of the rod is 7 in. The crank cheek is circular in cross section and is 1 in. in diameter. Distance AC is equal to 1 1/8 in. If the torsional shearing stress at the midlength of the cheek is equal to 10,000 psi for a cranking angle of 30 , find the value of the gas force on the piston.

Figure 1-1: Belt-driven air compressor.

Q1-2

A partial single-throw crankshaft drive is shown in Fig. 1-3. The shaft portion that appears has been isolated by passing a cutting plane at section O between the outboard and inboard bearings (the latter is not shown). Assume constant angular speeds; account for the weight of the gear; otherwise neglect gravitational and inertial forces. Draw the stress-resultant vector components at section O which are required for equilibrium of the system, and report the magnitude of each.

Figure 1-3