▁ 1 4 - cy l inder ▁two - row ▁radial ▁aircraft ▁engine , ▁produced ▁by ▁the ▁Br istol ▁Engine ▁Company ▁starting ▁in ▁ 1 9 3 6 . ▁The ▁T aur us ▁was ▁developed ▁by ▁adding ▁cyl ind ers ▁to ▁the ▁existing ▁single - row ▁Aqu ila ▁design ▁and ▁transform ing ▁it ▁into ▁a ▁tw in - row ▁radial ▁engine , ▁creating ▁a ▁power plant ▁that ▁produced ▁just ▁over ▁ 1 , 0 0 0 ▁horse power ▁( 7 5 0   k W ) ▁with ▁very ▁low ▁weight . ▁ ▁Design ▁and ▁development ▁Br istol ▁had ▁originally ▁intended ▁to ▁use ▁the ▁Aqu ila ▁and ▁Per se us ▁as ▁two ▁of ▁its ▁major ▁product ▁lines ▁in ▁the ▁ 1 9 3 0 s , ▁but ▁the ▁rapid ▁increase ▁in ▁size ▁and ▁speed ▁of ▁aircraft ▁in ▁the ▁ 1 9 3 0 s ▁demanded ▁much ▁larger ▁engines ▁than ▁either ▁of ▁these . ▁The ▁mechanical s ▁from ▁both ▁of ▁these ▁designs ▁were ▁then ▁put ▁into ▁two - row ▁configurations ▁to ▁develop ▁much ▁larger ▁engines , ▁the ▁Aqu ila ▁becoming ▁the ▁T aur us , ▁and ▁the ▁Per se us ▁becoming ▁the ▁Her cules . ▁ ▁The ▁T aur us ▁was ▁a ▁sle e ve ▁val ve ▁design , ▁resulting ▁in ▁an ▁extra ordin arily ▁un cl utter ed ▁exterior ▁and ▁very ▁low ▁mechanical ▁noise . ▁It ▁offered ▁high ▁power ▁with ▁a ▁relatively ▁low ▁weight , ▁starting ▁from ▁ 1 , 0 1 5   hp ▁( 7 6 0   k W ) ▁in