The fuel pump outlet (and thus the regen walls), turbine inlet, and
turbine outlet on a gas generator cycle are all lower pressures than
on staged combustion, and so should be lighter weight. Where is the
advantage to staged come in that makes it lighter for a given chamber
pressure?
On Tue, Dec 29, 2015 at 3:48 PM, David Gregory
<david.c.gregory@xxxxxxxxx> wrote:
It was stated that GG engines are lighter than alternatives. At a given
chamber pressure, that's not the case.
On Dec 29, 2015, at 12:40 PM, David Weinshenker <daze39@xxxxxxxxxxxxx> wrote:
On 12/29/2015 12:02 PM, David Gregory wrote:
There is nothing magical about the GG cycle that makes it lighter.
No, there's nothing "magic" about gas generator cycles - they're a
simple, effective solution. There's something a bit "demonic" about
staged combustion cycles (from the engine development point of view),
though; it's much harder to develop such an engine incrementally: you
sort of have to get everything working at once in order to test-run
anything.
I heard that a number of SSME prototypes were consumed in the
process of discovering a safe startup sequence... it wouldn't
surprise me if there were similar experiences "over there",
during the initial development of the RD-180.
-dave w