▁development ▁and ▁production . ▁The ▁Roll s - Ro y ce ▁Mer lin ▁was ▁also ▁starting ▁to ▁deliver ▁the ▁same ▁power ▁levels . ▁However , ▁the ▁V ulture ▁engine ▁installation ▁in ▁the ▁T orn ado ▁was ▁relatively ▁trouble ▁free ▁and ▁the ▁aircraft ▁itself ▁had ▁fewer ▁problems ▁in ▁flight ▁than ▁its ▁Sab re - eng ined ▁counter part . ▁The ▁third ▁prototype ▁( H G 6 4 1 ), ▁the ▁only ▁other ▁T orn ado ▁to ▁fly , ▁was ▁flow n ▁on ▁ 2 3 ▁October ▁ 1 9 4 1 , ▁power ed ▁by ▁a ▁Br istol ▁Cent aur us ▁CE . 4 S ▁sle e ve ▁val ve ▁radial ▁engine . ▁This ▁T orn ado ▁was ▁built ▁from ▁two ▁incomplete ▁production ▁air frames ▁( R 7 9 3 7 ▁and ▁R 7 9 3 8 ), ▁was ▁a ▁test bed ▁for ▁a ▁number ▁of ▁Cent aur us ▁engine / prop eller ▁combinations ▁and ▁was ▁the ▁pro gen itor ▁of ▁the ▁Haw ker ▁Temp est ▁II . ▁ ▁Oper ators ▁ ▁Royal ▁Air ▁Force ▁ ▁Spec ifications ▁ ▁See ▁also ▁ ▁References ▁ ▁Notes ▁ ▁Bibli ography ▁▁ ▁Dar ling , ▁Ke v . ▁Haw ker ▁Ty ph oon , ▁Temp est ▁and ▁Sea ▁F ury . ▁R ams gate , ▁Mar l borough , ▁W ilt shire , ▁UK : ▁The ▁Crow ood ▁Press ▁Ltd ., ▁ 2 0 0 3 . ▁. ▁ ▁Hann ah , ▁Donald . ▁Haw ker ▁Fly P ast ▁Reference ▁Library . ▁St am ford , ▁Lincoln