Stuart & Kathryn Fields wrote:
Is there anyone out there using fuel tanks filled with open cell foam? I've
heard that explosions are tamed as well as fuel slosh. I've also heard that
the foam must be replaced periodically. How often is the replacement
necessary? I'm using 100LL Av gas.

Fuel cells (bladders with foam) are pretty common in the auto racing
industry. They real purpose of it is to avoid the fuel from spraying
out if the tank is ruptured. Other than that I'm not sure what
"explosion" resistance you're going to get. I suppose it might
mitigate some sloshing. I'd make sure that I was getting the
max flow rate for takeoff if I were to use one in an aircraft.

The big drawback is that they drastically decrease the fuel
carried per unit volume.