My understanding is the trade is based on a couple factors:
1) Structural mass. In pump-fed rockets this pushes heavier propellant to
the bottom tank, otherwise you need to reinforce the lower tank to hold up
more mass. For small pressure-fed rockets local buckling is not going to be
the driving structural failure mode, so most amateurs can safely ignore
this.
2) Center of gravity. Placing the heavier propellant forward will make the
rocket more stable in flight. This is probably the more important criterion
for a small, passively stable rocket. You still need to plan for stability
at the end of burn, but if you're going supersonic that's probably not the
driving stability case. So putting heavy prop forward might allow you to
shave some fin area off.
3) There are likely to be secondary considerations that will be more
important than either of those with an amateur rocket. If you're using a
cryo or corrosive propellant you may want to keep the thermal mass and
fumes far away from electronics in the nosecone, for instance. Or having
the warm propellant on the bottom might reduce the risk of freezing as it
passes through the transfer tube.
On Fri, Mar 5, 2021 at 9:20 AM Rand Simberg <simberg@xxxxxxxxxxxxxxx> wrote:
It can't even get to our own star without a lot of gravity assists. But
it's not as bad as "Virgin Galactic" for something that can't even get
to orbit.
On 2021-03-05 09:12, Henry Spencer wrote:
On Thu, 4 Mar 2021, Anthony Cesaroni wrote:
"SpaceX probably has a milder version of the same issues on "Starship"
(stupid name...)."
Please define "stupid".
Jest.
What good is a starship that can't even reach Alpha Centauri? :-)
Henry