Our new Jellyfish balloon uses inflated struts. They don’t have an outer shell so there not true air beams. However, they are beams and full of air. Last night we tested the maximum pressure the unsupported tubes could take. The answer ended up being very complicated. The beam held fine at 1.1 psi then bubbled, stretched and burst as the pressure dropped down to 0.7 psi. We retested varying the pressure between 0.5 and 0.7 for 30 minutes, (est. first flight duration). It held just fine showing no stain. The beam need to hold 0.4 for the structural needs of the balloon. In flight the pressure will be monitored and controlled and now we know to keep the max pressure at or below 0.7 psi. Even a brief spike at higher pressure creates failures in the plastic matrix. Once that happens the beam is toast even at much lower pressures.
