Re: How Rockets Differ From Jets


Brad Guth wrote:
> >Fred J. McCall; I'd suggest you might want to look into strength of
> >materials insofar as unbuttressed construction goes.
>
> >Your Venus probe is so much drifting trash in short order, given this
> >type of "nice simple and quick" construction.
>
> >"Things should be kept as simple as possible, but no simpler."


The spaceplane I propose would have trusses, 'I' beams, and other
reinforcements. How about huge doughnut shaped tanks that encircle the
insides, holding immense quantities of fuel? My current thinking,
however, is running toward 'diamond' shaped tanks that lock together
like leggo toys. But there would still be trusses, 'I' beams, and
other reinforcements.


> I happen to like what "tomcat" has been proposing. However, I also
> appreciate the reality of what's known to work as opposed to what
> spendy carbon fibers and especially of what CNT might some day provide
> for us at perhaps just a million $/kg of what a new and improved
> spaceplane is likely to cost us.

The cost of CNT has, I believe, been exaggerated. It may -- right now
-- be expensive to oblivion. The University of Texas, however, has
been discussing the possibility of clothing being made from CNT. So,
the magic of mass production may make it a reasonably priced commodity
after all.

> It seems the creative solution is to cut further weight from the
> existing formula of shuttle, ET and SRBs, thus increasing payload and
> range at the same time as hopefully improving crew safety.

That is exactly what I have been proposing. My proposal does alter the
shape to more of a waverider, blended wing kind of craft. The ET tank
is trouble and it is good to be rid of it. The SRB's would make great
RATO (Rocket Assisted Take Off) units even if they do weigh 1,000,000
pounds each. Two of the SRB's would add 6.6 million pounds of thrust
to the spaceplane.

> Questions;
> Can SRBs be configuted for their assisting past 250,000'?

To the best of my knowledge they burn out based on run time, not on any
altitude restriction. Since a spaceplane will reach 250,000 feet much
more quickly than a vertical take off Shuttle the SRBs should continue
to burn.
>
> What's the typical thrust velocity of these SME/SRBs?

They weigh 1 million pounds and generate 3.3 million pounds of thrust,
each. They are solid fueled and thus have a lower ISP than the SSME's.
Exactly what the ISP is I don't know, off hand. Check out the Thiokol
web site.


tomcat

.