Generating the mass flow variation is the easy part. As you suggested,
propellant burn rate attributes can be utilised or even geometry. More
challenging is generating a targeted performance efficiency across both
operational phases without actively or passively modifying the throat area if
there’s not much altitude fluctuation.
As Henry points out though, a tightly constrained set of objectives in that
area would likely be more aspirational than to serve primary mission
practicalities.
Troy
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On ;
Behalf Of roxanna Mason
Sent: Friday, 26 February 2021 12:07 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Dual-thrust solid motors: their history?
I don't see any reason a dual exponent wouldn't work. GALCITE like propellants
burn at 2-3KSI and AP based can burn stable at 500 PSI.
A 6/1 thrust difference with the same throat area. High altitude would offset
the epsilon giving a higher Cf.
Just thoughts from a retired mainly liquid guy.
K
On Thu, Feb 25, 2021 at 4:35 PM Troy Prideaux <troy@xxxxxxxxxxxxxxxxxxxxx
<mailto:troy@xxxxxxxxxxxxxxxxxxxxx> > wrote:
Perhaps another possibility then is to utilise the sustainer propellant for
structural pressure support and operate the booster at higher pressures.
This would involve a more rigid sustainer propellant matrix and limit the
core geometric profile options and perhaps limit the available propellant
choices for the booster propellant which I suppose renders the idea a prime
candidate for the too-hard basket... nevertheless, I'm sure such ideas have
been investigated closely before.
Troy
of both
Unfortunately, Hawk had low-level capability, i.e. quite possible for all
burns to be at 1atm. (Although in the low-altitude case, where it didn'thave to
climb maybe 50,000ft at a steep angle, it might have been able to acceptsome
performance loss.)
Henry