Question

Calculate the approximate value of length at which supersonic after burning engine could be design in such a way that thrust at takeoff will be 29800 unit and maximum Mach number will be 2.12.

(a) 219

(b) 100

(c) 301

(d) 183.129

The question was asked by my college director while I was bunking the class.

Question is from Propulsion in section Propulsion and Fuel System Integration of Aircraft Design

Answer 1

Right choice is (a) 219

The best explanation: Given, Thrust = 29800 unit, Mach number M = 2.12

Now, Length L is given by, L = 3.06*T^0.4*M^0.2 = 3.06*29800^0.4*2.12^0.2 = 3.06*61.615*1.162 = 219 unit.