▁Model ▁ 3 4 0 s ▁flow n ▁with ▁Al ison ▁ 5 0 1 D - 1 3 ▁engines . ▁C - 1 3 1 D ▁Military ▁version ▁of ▁the ▁Model ▁ 3 4 0 ▁with ▁seats ▁for ▁ 4 4 ▁passengers , ▁ 3 3 ▁built . ▁V C - 1 3 1 D ▁C - 1 3 1 D ▁when ▁used ▁as ▁a ▁staff ▁transport . ▁C - 1 3 1 E ▁Electron ic ▁C ounter me asures ▁training ▁version ▁for ▁Str ateg ic ▁Air ▁Command ▁( S AC ), ▁later ▁designated ▁T C - 1 3 1 E , ▁ 1 5 ▁built ▁and ▁one ▁conversion ▁from ▁C - 1 3 1 D , ▁two ▁transferred ▁to ▁United ▁States ▁Navy ▁as ▁R 4 Y - 2 . ▁T C - 1 3 1 E ▁C - 1 3 1 E ▁red es ign ated . ▁C - 1 3 1 F ▁R 4 Y - 1 ▁red es ign ated . ▁RC - 1 3 1 F ▁Con versions ▁for ▁photo - mapping ▁and ▁survey , ▁six ▁convers ions . ▁V C - 1 3 1 F ▁R 4 Y - 1 Z ▁red es ign ated . ▁C - 1 3 1 G ▁R 4 Y - 2 ▁red es ign ated . ▁EC - 1 3 1 G ▁One ▁C - 1 3 1 G ▁modified ▁as ▁an ▁electron ics ▁tra iner . ▁RC - 1 3 1 G ▁One ▁C - 1 3 1 G ▁modified