Instruct: What is the average SFC in lb/(lbf·h) for engines with an Effective exhaust velocity (m/s) larger than 29,553, and a SFC in g/(kN·s) of 17.1?
Output: SELECT AVG SFC in lb/(lbf·h) FROM table WHERE Effective exhaust velocity (m/s) > 29,553 AND SFC in g/(kN·s) = 17.1