On 3/31/2018 9:59 AM, Henry Spencer wrote:
On Sat, 31 Mar 2018, William Claybaugh wrote:
Given a homogeneous mix, it would seem that the propellant at the bottom of an SRB would be no further from the nozzle then the propellant at the top of a 9"diameter motor (of 70" grain length)...
Although that's the worst case for the SRB, and the best case for the 9" motor -- the *average* kilogram of propellant is rather farther away in the SRB.
Still, Sutton8 says that even in the Star 27 apogee motor -- which is near-spherical, 800lb gross weight, with relatively short gas paths -- the propellant is 16% aluminum. Given that this is a "final stage", I'd think its details would be well optimized. Clearly there are some subtleties here.
