How does the change in altitude affect Mach Number when flying at a constant speed?
• The thrust of a jet engine is also affected by changes in altitude. Calculate the thrust of a Pratt & Whitney JT8D-17 jet engine (17,000 pounds at sea level) at different altitudes using the temperature and pressure results from Question 9, and the following equation: F = thrust at altitude F sl = sea level static thrust at takeoff (17,000 pounds) P = static pressure at altitude P sl = sea level static pressure (14.7 psi) F = F sl x P/P sl x sqrt(T sl/T) T = absolute temp (temp + 460) at altitude T sl = sea level absolute temperature (520 R) ALTITUDE PRESSURE TEMPERATURE # THRUST 1000 ft. A. 10,000 ft. B. 20,000 ft. C. 30,000 ft. D. • Graph the change in thrust with altitude for the Pratt & Whitney JT8D-17 jet engine. • Give your conclusions on thrust and flying at different altitudes.
