Re: Size of the proposed "new" space vehicle?

Mike Dennis wrote:
> I'm not convinced you know much more about these subjects than the buzzwords
> you're tossing about. Characterizing the shuttle as a waverider is quite a
> stretch. The nanotube cloth will be cool someday, but not quite yet. I
> agree it looks very promising. The atomic hydrogen approach, something I've
> worked with a little, has it's own problems and is more likely better suited
> to "NERVA"-like Nuclear or Inductive Reactance motors. But since neither
> exists today, there's a lot of work to be done. Free Enterprise by itself
> could make any of these work individually, but it takes a National effort
> (or a really really long time) to integrate it. It could be done by Free
> Enterprise, but free isn't really free--if you know what I mean.



The building of a waverider SSTO (Single Stage To Orbit) HTOL
(Horizontal Take Off and Land) is easier than many believe. And it can
be done quickly!

The secret is to stay with tried and true technology, off-the-shelf, as
much as possible. But the design can be challenging.

Even without nanotube cloth, without 'atomic hydrogen', the equilateral
triangle waverider can be built.

Triangles are easy to build, not difficult. Old ballistic nose cone
technology works: Corelle ceramic on carbon carbon on metal, with a
vacuum bottle outer inner hull -- as on the Shuttle -- to keep the
cabin cool.

Use SSME's because they use cryogenic fuel that also helps keep skin
and cabin cool and have a high isp as well as 450,000 pounds thrust.
The cabin can be roomy but use titanium or an even lighter composite
for things inside. The ship has to be very light because of 'dry
weight' requirements.

Use hydrogen slush tanks to keep fuel volume minimal. They exist.
They work -- it is just super compressed hydrogen.

Rig GLOW (Gross Lift Off Weight) to a 1:1 thrust to weight ratio.
Forget about Tsiolovsky's rocket equations because they apply only to
tublar vertical rise rockets, not HTOL waverider spaceplanes.

A rocketplane, spaceplane, spaceship, or whatever you call it, needs a
long (35,000 foot) runway and enough fuel for a good 5 minutes of burn
time. In your calculations include the fact that thrust to weight
ratio will increase rapidly as fuel is consumed. A 1:1 at takeoff will
become 4:1 near final 30 seconds of burn. So calculate the average of
2:1, not the takeoff 1:1.

The biggest waverider problem is aerodynamic surface heat. It can
exceed 7000 deg. F. Corelle ceramic can take more heat than that and
so can carbon carbon. Metals, however, cannot, so the surface has to
protect any metal underneath. Hence the importance of nanotube cloth,
but ballistic nose cone tests have proven that the protected metal can
be adequately protected from the heat. Cooling liquid hydrogen helps
as it picks up hull heat on it's way to the combustion chamber.

Now you know why thrust vectoring needs to include 'reverse thrust'
capability. So that reentry speed -- usually faster than entry speed
-- can be braked by rocket thrust. Main reason for this is to keep
hydrogen cooling to the hull and interior in operation. And, at the
same time, it reduces the heat caused by hypersonic air friction.

Note: You can also enhance braking with air brakes. Never heard of
air brakes? Jet fighters, and other aircraft, have them already! Why
weren't they used on the Shuttle. Well, they were but not fit for
early reentry braking. Nobody thought to make them strong and heat
resistent enough for that back in the 70's.

Use 'reverse thrust' along with 'air brakes' and reentry heating
problems may disappear. No need for ancient heat shields and
parachutes! Really!

Engine/tank fuel lines must be made of the most heat resistent
materials available. Titanium/tungsten alloy if necessary. DO NOT USE
HIGH TEMPERATURE SOLDER TO SOLDER FUEL LINES. Seamless welds only.
Temperatures in the engine compartment will probably exceed 3500 deg.
F. High temperature solder turns to watery liquid at 2500 deg. F.
Enough said.

Don't worry about short burn times like 3, or 4, or 5 minutes.
Glideslopes from 60 miles high and speeds of mach 20 will take you
anywhere on Earth. The Shuttle has proven it. It is a waverider and
it works well, except for easily broken silica tiles and low meltpoint
aluminum plate.

Because of extreme heat and the possible thermal shock of passing
through ice cold thunderheads when super heated use Pyrex glass for
canard portholes or canopies. Use an inside layer of polycarbonate to
stop UV rays -- wicked at high altitudes -- and for strength. Put
vacuum between the two layers to stop convected surface heat during
entry and reentry.

Understand that this triangle spaceplane would require 'real' American
backing. You have to 'really' want a spaceplane to . . . make one . .
.. before you die of . . . old age!

Really!


tomcat

.

Relevant Pages

  • Re: Pulling Train in Vegas, literally..............
    ... The nuclear reactor is used to heat up hydrogen which is the actual ... fuel that creates the thrust. ...
    (alt.vacation.las-vegas)
  • Re: Surface -- Orbit traffic
    ... but you also get thrust. ... but we also get a certain waste heat problem - the airframe ... carrying the shuttle, or dropping the shuttle but taking the cargo on ... but how would laser air-rams or laser water ...
    (rec.arts.sf.science)