Building an Experimental Airplane, The Vans RV-7A | EP2.7 Fuel Tank, Part II - Ryan Flys Watch in HD on YouTube! Share on Facebook! I build the majority of the right fuel tank for the Van's RV-7A. I start with interior ribs, and more tank taffy (ProSeal or Flame Master gas tank sealant) than I've worked with. Interior ribs are fairly straightforward, after which the end ribs are worked on. These include more fittings and hardware than any of the ribs up to this point.