Norm:
A logarithm is an exponential function.
Bill
On Sunday, September 4, 2016, Norman Yarvin <yarvin@xxxxxxxxxxxx> wrote:
On Fri, Sep 02, 2016 at 03:04:56PM -0400, William Claybaugh wrote:
You can do as little as 50 psia against vacuum and 150 psia to sea levellost
air; look into Bob Truax's Sea Dragon work for reference.
That said, note that he was planning on using Lox / LH2 to recover the
Isp. But as a general rule mass fraction improves as the operating
pressure of a pressure fed liquid drops...and mass fraction has an
exponential effect on performance, whilst Isp is merely linear.
Uh, the rocket equation is the other way around: Isp in the exponent,
with mass fraction being linear. (Or, equivalently, Isp linear, and
the logarithm of mass fraction.)
