RC Airship Thundership Mk I Daedalus design

This is the current design for my first radio controlled airship, the Thundership Mk. I "Daedalus"
It is planned to be an 8 foot long, helium filled, Mylar balloon with an estimated payload between 9-10 ounces.
I am just waiting on the roll of Mylar to arrive to get started.  I will also need around 30-35 cubic feet of helium so if you know where to get some on the cheap please let me know.
*The hardware may be changed if it needs to be lightened.