Apropeller is operating initially at j = 1.0. for the blade section at 70 percent of the maximum radius, find the value of the advance ratio where the angle of attack is reduced by 5 degrees.

An ammonia compressor has a 5% clearance volume and displacement rate of 80 l/s and pumps against a condensing temperature of 40°c. for two different temperatures of -10°c and 10°c, compute the mass flow rate of refrigerant assuming the clearance volumetric efficiency applies. discharge specific volume corresponding to-10°c and 10°c are 112.5 l/kg and 95 l/kg, respectively.