Lift does not scale with size the way people assume. It scales with volume, which is why the jump from 13 feet to 30 feet is so much bigger than it looks.
The basic sum
A balloon rises because the air it pushes out of the way weighs more than the helium inside it. Lift is that difference, minus the weight of the skin.
Roughly one ounce of lift per cubic foot of helium at sea level. A 13-foot blimp holds 170 cubic feet, so call it ten pounds gross, about three pounds net once the envelope and fittings are accounted for.
Volume grows faster than height
Double the height and you multiply the volume by about eight. That is why a 30-foot blimp needs 1,510 cubic feet where a 15-foot needs 255.
It is also why the price curve is steep: $1,258 at 15 feet, $6,772 at 30. You are not buying twice as much balloon; you are buying eight times as much of everything.
Altitude and heat cost you lift
Thinner air displaces less weight, so the same balloon lifts less in Denver than in Phoenix. Hot air is thinner too.
It is a real effect rather than a large one at advertising sizes, but if you are at elevation and flying near the limit, expect the balloon to sit slightly lower on its tether on a hot afternoon.
Why net lift is small on purpose
Three pounds sounds feeble until you remember what it has to do: hold a tether taut at 120 feet and nothing else.
More lift would mean more gas, more cost per fill and more load on the anchor in wind. The balloon is sized to fly, not to lift anything.
Ask for a quote. Call 1-800-791-1445 or email sales@arizonaballoon.com and tell us the size and whether you want it printed.
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