An aircraft with wing aft tail configuration has tail efficiency of 0.95 and tail volume ratio of horizontal tail is 0.7. Determine pitching moment coefficient slope for the tail. Given lift curve slope of tail is 4.2 per rad. Consider downwash derivative as 0.6.

Given, tail efficiency e = 0.95, tail volume ratio of horizontal tail v = 0.7, lift curve slope of tail c = 4.2 per rad, downwash derivative d = 0.6 Pitching moment coefficient slope for the tail = -e*v*c*(1-d) = -0.95*0.7*4.2*(1-0.6) = -1.1172 per rad.