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@KrajciTom I should search this myself, but what do gliders use the ballast for? It seems like being lighter would almost always be better?

@inktomi @KrajciTom almost certainly for CG reasons.

@younata @inktomi

Let's say a given glider has a best glide ratio of 40:1.

When the glider is light, its best glide speed is slower.

Add ballast and the glider, surprisingly, can still achieve a best glide ratio of 40:1, but at a higher speed.

But there ain't no such thing as a free lunch.

With ballast, the glider's minimum sink rate is higher. It can't climb as fast in thermals.

But in straight runs it catches the lighter glider....IF it's a fairly strong lift day.

The wing ballast tanks shift the C/G forward, so there is a third, small, tank in the tail.

My tail tank should be able to hold 10 - 12 pounds. (If I need more mass in the tail, beet juice has a specific gravity of 1.35!)

How much will my wing tanks hold? A crude estimate says 25 gallons per wing. That can add a bit over 400 pounds.

After I get the valve controls working, I'll measure how much water the tanks actually hold.

A complete C/G analysis will happen after painting and installation of all equipment.