Chapter 1, Problem 1.10P

Consider a Lear jet flying at a velocity of 250 m/s at an altitude of 10 km. where the density and temperature are $0.414{\text{kg/m}}^{\text{3}}$ and 223 K, respectively. Consider also a one-fifth scale model of the Lear jet being tested in a wind tunnel in the laboratory. The pressure in the test section of the wind tunnel is $1\text{atm}\text{=1}\text{.01}\times {\text{10}}^5{\text{N/m}}^{\text{2}}$. Calculate the necessary velocity, temperature. and density of the airflow in the wind-tunnel test section such that the lift and drag coefficients arc the same for the wind-tunnel model and the actual airplane in flight. Note: The relation among pressure, density, and temperature is given by the equation of state described in Problem 1.1.