Could you explain that last part (" 50% margin for the harder to model variation of forces over the sphere") - do you mean with respect to the ability of the internal pressure of the sphere to keep the sphere rigid and spherical?

-------- Original Message --------
 On January 30, 2018 4:57 PM, Tim <xxxxxx@little-possums.net> wrote:

>
> I used coefficient on the order of 1, area 1.5 m^2, and drag 20 kN to
> get 13 kPa, then allowed about 50% margin for the harder to model
> variation of forces over the sphere.