//consider the engine of example 9.1,datas are same as 9.1
Pa=1.034*10^4;//total power available(N/m^2)
n=0.83;//propeller efficiency
Nmech=0.75;//mechanical efficiency
rpm=3000;//for engine-propeller combination(revolution per minute)
b=9*10^-2;//bore(meter)
s=9.5*10^-2;//engine stroke
N=6;//number of cylinders
d=%pi*b^2*s*N/4 //displacement(meter)