▁t anks , ▁ball ast ▁b ags ▁and ▁other ▁heavy ▁items , ▁as ▁well ▁as ▁to ▁allow ▁the ▁crew ▁to ▁travel ▁between ▁the ▁cars , ▁and ▁its ▁removal ▁effect ed ▁a ▁considerable ▁reduction ▁in ▁weight ▁together ▁with ▁improved ▁man oe uv rab ility . ▁Instead , ▁the ▁various ▁loads ▁were ▁concentr ated ▁at ▁the ▁bulk head s ▁and ▁susp ended ▁from ▁the ▁radial ▁w iring ▁that ▁maintained ▁the ▁shape ▁of ▁the ▁h ull . ▁The ▁gas - b ags ▁were ▁sh aped ▁to ▁accommod ate ▁a ▁new ▁internal ▁cor rid or , ▁created ▁by ▁the ▁provision ▁of ▁invert ed ▁" U " - sh aped ▁rib s ▁above ▁the ▁two ▁lowest ▁longitud inal ▁members , ▁which ▁also ▁allowed ▁access ▁to ▁the ▁fuel ▁t anks ▁and ▁ball ast . ▁An ▁improved ▁system ▁of ▁pip es ▁linking ▁the ▁fuel ▁t anks ▁enabled ▁faster ▁ref u elling , ▁and ▁could ▁be ▁used ▁to ▁j ett ison ▁fuel ▁in ▁an ▁emer gency . ▁However , ▁as ▁with ▁earlier ▁designs , ▁do ped ▁lin en ▁was ▁used ▁for ▁the ▁h ull ' s ▁outer ▁covering ; ▁and ▁being ▁abs orb ent , ▁just ▁a ▁few ▁hours ▁of ▁rain ▁could ▁add ▁around ▁a ▁ton ▁of ▁water ▁to ▁the ▁weight . ▁ ▁Prop ulsion ▁and ▁testing ▁The ▁R 2 3 X ▁class ▁were ▁power ed ▁by ▁four ▁ ▁Roll s - Ro y ce ▁E agle ▁VI ▁engines ▁– ▁later ▁and ▁more ▁powerful ▁versions ▁of ▁those ▁employed ▁by ▁the ▁ 2 3 ▁class , ▁but ▁arranged ▁in ▁a ▁similar ▁manner