posted on Nov, 8 2011 @ 06:02 AM
Originally posted by ignorant_ape
reply to post by Flyinghaggis
i dont care wether you agree or not - but please tell us how this tech would get a 10000kg payload to 42 km ?
I did some quick calculations using the data
here for air at 40,000m
(131,000 ft). I assumed that the pressure inside the balloon was equal to that of the air outside the balloon, and assumed that the helium mass could
be approximated using the ideal gas law (using R values from the textbook "Fundamentals of Thermal-Fluid Sciences"). I ignored the mass of the
balloon itself, and the mass of the structure, so these values I get are rather conservative. I tried to estimate the size of the balloons required
for a tandem balloon airship to support 100,000 kg at 40,000m.
I assumed the shape of the balloons to be spherical, which has the least surface area compared to it's overall dimension for any shape. Any other
shape would increase the amount of balloon required, hence increase over all mass.
I calculated that each of the 2 balloons would need to have a diameter of approximately 302.5 metres. Bearing in mind that this did not take into
account the mass of the balloons or the support structure which would have to be at least as long as 302.5 metres to support the balloons. This added
mass would make the balloons even larger.
Given that these are conservative estimates, these would have to be some serious balloons to handle winds and severe weather whilst reaching those
heights. These calculations are pretty rough, and I can show working if anyone wants it. I might even write some simple MATLAB code to calculate the
required volume of balloon, and try to take into account things like mass of balloon and structure. But it's past my bedtime and I shall go to bed
now.
Edit to add: silly me, I used a payload of 100,000 kg instead of 10,000kg as you had stated.
I think that's a sign I need to go to bed
now.
edit on 8/11/11 by Curious and Concerned because: see above