Repost: Hydrogen peroxide helicopter (and Len Cormier's Space Van)

My earlier response on sci.space.tech seems to vanished
into outer space--along with a number of other replies on
sci.space.tech.

"Lawrence Gales" wrote in message
news:Pine.WNT.4.58.0407172228370.1384@your-kgj38sd53j...
[snip]
You might check out Len Cormier's Space Van 2008:

http://www.tour2space.com/sv2008/sv2008.htm

Len claims a number of advantages in *slowly* getting an orbiter to a high
altitute (about 70,000 feet) and then releasing it at a moderate speed,
about 350 mph:
- Greatly reduced structural weight due to
o Not having to fight your way at high speed through the lower
atmosphere (remember the shuttle would tear itself to pieces if it
did not throttle down to 65% around 40,000 feet)

Unless you have a carrier aircraft bringing the launch vehicle up to
altitude you're trading off one sticky problem for another. You still
must use an oxidiser, if you expect the launch vehicle to be airbreathing
until using rocket propulsion you have the issue of added weight unless
you jettison something.

Yes, airbreathing is not a promising way to climb
to very high altitudes because of extreme density
changes. Rocket propulsion, however, albeit heavy
initially, is a good way to climb to high altitude.
The high initial mass of a rocket system is of little
consequence, if the propellants are cheap, and the tanks,
engines, and fabric-covered, span-loaded, truss structure
wing are light. The resulting system is light at altitude,
where being light is important. Moreover, this part of the
system is strictly subsonic and does not continue to orbit
with the orbiter.

o Not having to have strength in as many directions as its attitude
is always nearly horizontal

Now you have TWO structural problems instead of one. You must still have
the strength to withstand the acceleration when the rocket is thrusting
(2-7+G plus dynamic loading) AND you must have the horizontal strength to
withstand the structural load of being hoisted to altitude (probably 2-5G
plus dynamic loading) and this horizontal lift must be performed while
fueled

Acceleration is much less. Initial thrust-to-mass is
only about 0.4. Normal loads from lift are less than
2 g's--with initial ultimate normal loads of 3 g's,
allowing for safety factor. Most importantly, dynamic
pressure is held to less than 2500 Pa (52 psf); this
avoids panel flutter problems, as well as structural
load problems on the orbitr aero surface which can now be
designed for low-q reentry, approach and landing.

o Less need for streamlining and thus more efficient packaging

How high do you expect to lift this thing slowly. Unless its up to
~200,000ft+, you are still going to have big aerodynamics problems.

Separation altitude is 21,300 m (around 70,000 ft). This
is quite high for mach 0.5. Altitude at orbital speeds
is more like 120 km (nearly 400,000 ft) --which yields low
heating, as well as nearly neglible aero loads.

- Greatly reduced chamber pressues (e.g., 1400 psi vs 3000 psi) leading
to *much* longer engine life and reduced costs

Why do you select the particular value's you select for chamber pressure?

The baseline is an Aerojet AJ26/Kuznetsov Nk-33;
we derate to 80 percent for greatly reduced maintenance
costs.

- Greatly reduced mass ratio: if we compare SSME (ground launch) with
RL-10s, the MR reduces from 9.5 to between 6.5 and 7 --- a huge
difference

This mass ratio only counts if you forget the carrier and you find that
you will have a greatly reduced total mass to orbit.

The important paramater is cost, not gross mass.
As for performance, orbiter mass ratio and staging
point is what counts, not the mass ratio of earlier
stages.

- A much smaller minimum size vehicle: 80-100 tons versus 500-1000
tons



I would say that slow airlaunch to a very high altitude has a very large
advantage

Debateable

While you debate, we'll go to orbit--but only if
we can manage to raise the funds necessary to develop
the Space Van 2008.

News groups are great. You can always count on a
straight man. ;)

Best (regards),
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com