JF Mezei wrote on Thu, 2 May 2019
16:05:14 -0400:

On 2019-05-02 06:59, Jeff Findley wrote:

Note from above the OMS propellant pressure was regulated to:

The primary regulator outlet pressure at normal flow is 252 to 262
psig and 247 psig minimum at high abort flow, with lockup at 266
psig maximum. The secondary regulator outlet pressure at normal
flow is 259 to 269 psig and 254 psig minimum at high abort flow,
with lockup at 273 psig maximum.

RCS system he

The primary regulates the pressure at 242 to 248 psig, the
secondary at 253 to 259 psig.

Thanks. Expected much different pressure differences. For a capsule as
small as Dragon2, couldn't they have a single tank/helium concept with
different regulators to feed Draco vs Super Dracos ?


Which part of 'pressure fed rocket engine' do you not understand?


In the case of Dragon2, do the Draco systems use the same hardware as
for Dragon 1? (which would simplidfy engineering SuperDracos as totally
separate system).


No, they built it all totally different just for the **** of it.


Since mass is so critical to flights/payload, I would have expected the
maximum possible mass savings with as much shared hardware as possible.


If mass is that critically important you don't build pressure fed
rockets.


But I guess sometimes extra mass is worth it if you can reuse a system
that has been already desingned and focus only on the new engines.


You're (foolishly) leaping to supporting your own position. The way
you want to do it takes MORE hardware and MORE complexity than the way
they did it. If mass is important you don't add a bunch of extra ****
so as to get multiple uses out of a piece of hardware.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn