Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
.... look into the water rocket idea. Accelerations are huge and
will easily outperform a chemical rocket over that sort of distance.
I find that rather implausible.
The ultimate performance of a rocket, hydraulic or
otherwise, is limited by the bursting pressure of
the chamber. The hydraulic rocket suffers a
performance degradation factor f, on the order
of f=.75, because the pressure at the end of the
thrust phase is about half of the initial pressure.
A chemical rocket need not suffer any such degradation.
To see this, consider the intermediate case, namely
a water-rocket pressurized by a chemical reaction.
If the reaction goes to completion at t=0, the
situation is just like an ordinary water rocket.
Things can only get better if the reaction continues
longer, maintaining peak chamber pressure until the
water is exhausted.
It is true that a water rocket optimized for drag
racing will outdo a modest chemical rocket designed
to develop "only" 10 or 15 Gees. But that's just
a truism and an optimization issue ... you can
design rocket engines that burn muuuuch faster
than anything Estes sells ... water rockets have
no fundamental performance advantage.
Amusing water-rocket page, including diagrams of
the Ian Clark hold-down mechanism:
http://users.hubwest.com/gordo/waterrocket.html