ing ▁model ▁; ▁racing ▁model ▁ ▁B lower : ▁tour ing ▁model ▁ ▁@ ▁ 3 , 5 0 0 r pm ; ▁racing ▁model ▁ ▁@ ▁ 2 , 4 0 0 ▁r pm ▁ ▁The ▁B lower ▁Bent ley ▁was ▁born , ▁more ▁powerful ▁than ▁the ▁ 6 ½ ▁Lit re ▁despite ▁lack ing ▁the ▁two ▁additional ▁cyl ind ers . ▁The ▁down side ▁was ▁that ▁B lower ▁Bent le ys ▁consum ed ▁ 4 ▁lit res ▁of ▁fuel ▁per ▁minute ▁at ▁full ▁speed . ▁ ▁Production ▁The ▁original ▁No . 1 ▁had ▁a ▁t aut ▁canvas ▁top ▁stretch ed ▁over ▁a ▁light weight ▁We ym ann ▁al umin ium ▁frame , ▁housing ▁a ▁two - se at ▁body . ▁This ▁presented ▁a ▁very ▁light ▁but ▁still ▁resist ant ▁to ▁wind ▁structure . ▁It ▁was ▁officially ▁presented ▁in ▁ 1 9 2 9 ▁at ▁the ▁British ▁International ▁Motor ▁Show ▁at ▁Olymp ia , ▁London . ▁ ▁No . 1 ▁first ▁appeared ▁at ▁the ▁Es sex ▁six ▁hour ▁race ▁at ▁Brook lands ▁on ▁ 2 9 ▁June ▁ 1 9 2 9 . ▁However , ▁the ▁car ▁initially ▁proved ▁to ▁be ▁very ▁un re li able . ▁W . O . ▁had ▁never ▁accepted ▁the ▁B lower ▁Bent ley , ▁but ▁with ▁effective ▁company ▁owner ▁and ▁financial ▁back er ▁Bar n ato ' s ▁support , ▁B irk in ▁persu aded ▁W . O . ▁to ▁produce ▁the ▁fifty ▁super charg ed ▁cars ▁necessary ▁for ▁the ▁model ▁to ▁be ▁accepted ▁for ▁Le