Right now the big thing we’ve got going at the shop is ballast tanks for 24-06. Brad didn’t put any ballast into 24-01, his Tetra-15. And for 24-03 we installed a set of valves and used ASW24 ballast bags–which work great. The other gliders in the series will get field-installed bags at builder option, and -07 and -08 are slated for self-launch, and will have batteries in the wings instead of water.
But for 24-06 we’ve gotten serious about massing up with DHMO, and builder Tom wants some substantial ballast capacity. So we’re basically partitioning off the entire leading edge to fill with water. Our calculations are that it will be about 200 lbs per side, or 400 lbs total. Tom did a bunch of experiments to arrive at a water-barrier epoxy formulation to seal off the inner surface of the wing, and also helped us by making tooling for the two end dams and the three slosh baffles (three being a particularly propitious number) between them.
Right now I’m developing the dump valves that install into the wing root to let the water go. They’re very similar to the valves we put into 24-03, but are adapted at the ends for the fixed tanks instead of the bags.