45 and 47 as well as the other stiffeners shown in fig2 as noted above the longeron 52 has branching flanges 62 and 64 which extend over the adjacent surfaces of their respective tubes or lobes 42 44 and 46 which flanges are attached thereto to support and seal such lobes as shown or indicated in fig2 and 3 thus in fig2 one can see flange 64 mounted over an adjacent surface of lobe 44 and flange 62 mounted under a surface of lobe 46 also rounded longeron ribs 48 and 51 support the end domes of their respective lobes e g lobe 46 as shown in fig2 the cruciform shaped longeron 52 and 53 serves not only to act as a load carrying structure but can also be used at upper body 68 as an attach point to the fuselage or body of an aircraft or other vehicle not shown the respective tubes or lobes are capped with composite end domes e g domes 50 54 and 55 as shown in fig2 the tank tubes e g lobes 42 44 and 46 are fabricated in one of several ways skins can be filament wound on a rotating mandrel the winding.