dre wrote:

4 min of thrust.....want to use a sam to carry 5tons of payload into space?
the delta clipper was an effort to have only 1 stage,failed because the tank
ruptured.
and was to heavy anyway

4 minutes of thrust is a long time for a rocket.

Rockets rely on the size of their thrust, relative to jet and prop
engines, and not the length of time.  With a 2:1 thrust to weight
ratio, orbital velocity is possible with about 2 minutes of thrust.

The delta clipper was not properly funded, or the program was cut short
for other than technical reasons.  A tank rupture simply called for a
modification or replacement.

The reason rocket scientists are having such a hard time is that they
do not want to use wings.  This destroys, in their minds, the
distinction between rockets and aircraft.  Aircraft engineers are
regarded as a different group than the rocket engineers . . . and so on
and so forth.

Another reason is that they are not thinking 'lighten the load'.  New
materials and designs should half the dry weight and this is roughly
equivalent to doubling the DV.  It is not impossible.  They must learn
to use internal structures for more than one thing, and use vacuum and
air as much as possible.


tomcat