Re: Letter to Tomcat on steam


Brad Guth wrote:
"tomcat" <jlavine@xxxxxxxxxxxxx> wrote in message
news:1166966535.853021.303330@xxxxxxxxxxxxxxxxxxxxxxxxxxx

That's getting your "Fat Albert" numbers a touch better off, though now
at 315 tons per each of 50 massive landing gears. What about that
notion of utilizing the super-conducting electromagnetic rail launch of
less than a mile instead of taking 9+ miles of spendy tarmac, along with
all those custom 200+ massive (nearly solid composite silicon) wheels of
friction and of the unavoidable horrific inert mass to boot?

BTW; what is the maximum takeoff wheel/tire loading as we currently
know of?

Here's my new and improved rant as to LRB assisted Lapcat/Skylon
applications.

Rigid airships as spaceplanes, or vise versa:

This Skylon/Lapcat is simply way overkill performance for the rigid
airship needs of Venus, but at least it showing that our applied laws of
physics and modern composites should function on behalf of
private/commercial spaceplanes without incorporating all of the usual
inert mass of cloak and daggers as being associated with our NASA, or of
anything MI6/KGB/NSA.

Tomcat's fat SSTSO (Single Stage To Sub-Orbital) waverider/spaceplane is
gradually becoming quite real, though still a rather spendy and brute
force of a energy consuming ride, though at least it's not of
hocus-pocus physics or involving the smoke and mirrors of all those
NASA/Apollo fiasco years, and subsequent decades of their infomercial
crapolla with the sorts of their hocus-pocus rocket-science as based
upon thir conditional laws of physics that simply doesn't add up. Using
brute force and absolute volumes of fuels (mostly LOX/LH2), along with
incorporating a great many composites in order to keep their inert mass
down to a dull roar seems quite doable, exactly as having previously
been specified by "tomcat", and for that matter myself with reguard to
those nifty Venusian rigid airships.

I believe this only gets better yet, once the fully robotic and reusable
LRBs are those of a commercial production run that's offering those
items as the necessary initial thrust boosters, as this is when these
Lapcat/Skylon spaceplanes will become the most payload capable of
hauling and deploying serious payload tonnage, as well as configured on
behalf of accommodating greater volumes of whatever into LEO/ISS orbits.
The purely fly-by-rocket alternative if made equally composite should
still far outperform the complex Skylon/SABRE in sheer payload tonnage
that's getting deployed past LEO/ISS, simply because of the ratio of
inert mass is by far the best if going via robotics where all is
benefiting via composites, much greater density of fuel(s) and otherwise
of extremely compact rocket engine(s).

Lapcat SSTO
http://www.reactionengines.co.uk/lapcat.html

Skylon SSTO
http://www.reactionengines.co.uk/skylon_vehicle.html

Each of these utilizing similar multitask/hybrid SABRE thrusters that
are likely going to become the near future of whatever's suborbital, and
even of whatever limited orbital flights can more affordably deliver,
along with impressive add-on LRBs making either of those spaceplanes
into commercial payload capable deployments of getting significant
tonnage into LEO/ISS or on behalf of commercial POOF applications.

What's needed are the 10+ meter by 40+ meter of payload volumes, and of
100+ tonnes getting past LEO/ISS. Until then, a suggested 10 tonne
payload of a somewhat limited volumetric capability is still way better
off than anything that's getting purely fly-by-rocket deployed as of
today's conventional means.

Before long, and especially if either of these new and improved
fly-by-reaction/rocket spaceplanes are going for LEO/ISS or commercial
POOF applications, as such they'll most likely each need to apply a good
pair of fully reusable LRBs, by which each of these strap-ons/latch-ons
of secondary fly-by-rocket LRBs, as based upon the greater fuel density
of h2o2/c3h4o or whatever's better (perhaps good for 180+ km worth of 45
degree flight boost, or roughly a minute worth of absolutely impressive
thrust) as easily robotic/remote flown back to Earth and making
conventional landings on their original tarmac if need be. (thus near
zero LRB recovery efforts or other recovery factors)

Short of their accomplishing spendy and somewhat touchy in-air
refuelings (which might not even be all that viable), LRBs will likely
remain as essential for getting this spaceplane tonnage and of it's
considerable aerodynamic drag from ground zero past the first 3+ km/s
mark and past as much altitude as possible, that is unless whatever
commercial payload tonnage or volume isn't a factor. So, unless going
nuclear or whatever spaceplane process can vaporise the likes of water
or much rather on behalf of processing h2o2 quickly enough, LRBs are
still going to become the best reusable ticket in town. Obviously fully
disposable SRBs of mostly composites (large STINGERS) will otherwise
remain as the short burn (STAR kicker) alternative for getting such
volumes and otherwise massive spaceplanes up to their initial
aerodynamic maximum velocity.

Personally, I think Lapcat or especially Skylon SSTO at merely 79% fuel
w/o LRBs is asking a bit much of those hybrid reaction engines that are
supposedly capable of 200~300 tonnes thrust (half again that of the
proven SSME), which sort of makes one ask, as to once operating above 25
km as to where all the spare fuel is coming from in order to feed a pair
of these thirsty engines, and for any sufficient amount of time as
necessary for obtaining LEO/ISS orbital status, along with fuel to
spare.

Spendy R&D is a given. However, I do believe that operational cost are
another given factor that needs to be incorporated within whatever plan
of action, that is unless all of us are suddenly going to become
billionaires and those warm and fuzzy big energy cartels, that
supposedly wouldn't dream of further gouging us, manage to discover
unlimited fuel(s) and/or yellowcake reserves that we currently don't
know about.

I've asked, what's the best swag as to the all-inclusive mass of the
SABRE ?

Since there's no SABRE mass specified, perhaps we can only assume that
it's currently a rather hefty sucker, at perhaps twice the mass of a
given SSME, making their naked SSBRE worth 6,000+ kg each (not including
all of the airframe internals and external aerodynamic infrastructure).
-
Brad Guth


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I am very practical in my SSTO design efforts. Why? Because private
enterprise has to avoid the 100 billion dollar programs that only NASA
and the DOD can afford.

So, I select the SSME over untried and unproven engines. The SSME
works every time and is rated for 'manned' spaceflight.

I avoid new materials that have yet to see the 'light of day'. Today,
however, titanium is a fully developed and fully machinable metal.
Ceramics work when it comes to high temperatures with Corelle and
Silica Tiles being extraordinary for dealing with up to 20,000 deg. F.
temperatures.

Huge doughnut tanks welded side by side should provide enormous liquid
fuel capacity while providing a very strong hull besides. Because of
embrittlement stainless steel may have to be used, however, both for
the tanks and for the under skin of the SSTO. The center of the
doughnut tanks could be filled with long cylinders of additional fuel
and, perhaps, even a walkway so that crew can examine the tanks and
engines from the inside.

Cockpits can be quite large while crews can be small. On a large SSTO
or SSTP the massive tanks will leave lots of design space for crew
quarters. Big doughnut tanks with large center holes will provide the
space for crew quarters and cockpit. That way you surround the crew
with tons of hydrogen to protect against radiation.

Small crews, 2 or 3 at most, are all that is necessary with today's
guidance and control systems. Computers can completely automate the
process if necessary.

On a large ship a couple of thousand pounds of food does not represent
any weight restrictions. Ditto for oxygen and water. What is a ton or
two when you are throwing 100 + tons into orbit and carrying 15,000
tons of fuel? This is why Big is Better.

Fat Albert is meant to be a Big Heavy Lifter capable of meeting today's
space requirements, not a super tech spaceship requiring years of R&D
and massive funding.


tomcat

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