5’ ht => 1257*5 = 6283 cu ft *28.32 L/cuft = 177940 L
(It’s a cylinder, essentially.)
2.205 lb/kg If 1 L lifts 1 gram, then
(177940 L * 1g * 1kg * 2.205 lb)/(1 L * 1000g * 1kg) = 392.36 lbs
I repeat my #1632
6m diameter, plan area c28m2 mean thickness maybe 1¼m = total volume 35 m3.Amazing how much our results differ.
Helium lift 1Kg/m3 35Kg =c.80lb at sea level. Reduce by 25% to allow for altitude Gross lift balloon and payload=60lb (best mental estimate, but would be surprised if out by more than 10lb either way)
On One hand, you used a calculator and worked to 5 significant figures.
On The Other Hand, I did it in my head to 2.
The Gripping Hand is you made a mistake in the first line : Diameter does not equal radius
(When Admiral Tryon confused the two in 1893, he lost his flagship) oops!
