How many liters of helium is needed to lift 1kg of goods at 20 Celcius?

You need 914 litres of helium to lift 1kg. This is only slightly less than 1 cubic metre which give you an idea of the blimp size you need. How did I get there?

You need 163.3 g of helium to lift 1kg, helium density is 0.1786 g/L, that gives 914 litres neglecting the weight of the blimp so you want to make it a a little bigger. The sanity check is this agrees with How Stuff Works approximation of 1 gram of lifting force for each litre of helium Interesting blimp fact: The GZ-20A size blimps (Spirit of Goodyear; Spirit of Innovation; Spirit of America) are 192 feet long, 55 feet in diameter, and 59.5 feet high, with 202,700 cubic feet (5739 cubic metres) of helium and a gross weight of 12,840 lbs (5905 kg).

You need about 700g of helium to generate 1kg lift (assuming the helium is at the same temperature and pressure as the surrounding air) See here: newton.dep.anl.gov/askasci/phy99/phy9947....

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.