▁co - ordin ating ▁role . ▁ ▁It ▁produced ▁specific ations ▁and ▁commission ed ▁pilot ▁models ▁for ▁each ▁tank ▁to ▁assess ▁different ▁companies . ▁ ▁One ▁compet ing ▁company ▁would ▁then ▁be ▁appointed ▁the ▁design ▁lead ▁for ▁further ▁development ▁of ▁that ▁tank . ▁ ▁This ▁followed ▁a ▁similar ▁pattern ▁to ▁the ▁R AF ' s ▁Air ▁Ministry ▁Spec ifications . ▁ ▁In ▁November ▁ 1 9 4 1 , ▁W ▁A ▁Rob oth am , ▁the ▁Chief ▁Engine er ▁of ▁Roll s - Ro y ce ' s ▁Ch ass is ▁Division ▁who ▁had ▁been ▁the ▁main ▁pro ponent ▁of ▁the ▁C rom well ▁and ▁Meteor ▁works ▁was ▁second ed ▁into ▁the ▁Ministry ▁of ▁Supp ly ▁to ▁become ▁the ▁Chief ▁Engine er ▁of ▁T ank ▁Design . ▁Rob oth am ▁started ▁a ▁fresh ▁look ▁at ▁tank ▁design , ▁starting ▁with ▁w eld ed ▁h ull s ▁and ▁final ▁delivery ▁of ▁the ▁ 6 - p ound er ▁gun ▁( des igned ▁in ▁ 1 9 3 8 ). ▁The ▁role ▁was ▁outside ▁of ▁the ▁usual ▁hierarchy , ▁allowing ▁Rob oth am ▁to ▁co - ordinate ▁efforts ▁between ▁D TD ▁and ▁industry ▁while ▁adding ▁some ▁much ▁needed ▁technical ▁advice ▁to ▁the ▁T ank ▁Board ▁and ▁General ▁Staff . ▁ ▁In ▁ 1 9 4 2 , ▁the ▁Chair man ▁of ▁the ▁AF V ▁Division ▁( Vis count ▁We ir ) ▁was ▁appointed ▁as ▁the ▁Chief ▁Executive ▁for ▁T ank ▁Design , ▁and ▁became ▁the ▁chairman ▁of ▁the ▁T ank ▁Board . ▁ ▁The ▁T