Repost:: Hydrogen peroxide helicopter

My earlier responses on sci.space.tech seems to have vanished.

Andrew Nowicki wrote in message
...
John Carmack wrote:

How is lifting the launcher and payload slowly
through the lower atmosphere an advantage?

One must distinguish between thrust loads on the
structure and aerodynamic loads on the structure.
There is not likely to be much gain with respect
to thrust loads.

The potential gains of getting to high altitude
"gently" stem from the relief from panel flutter
and from aerodynamic loads and load distribution.
Even VTO ELV's are sensitive to "q x alpha." Lifting
reentry followed by horizontal approach and landing
does not have to involve prohibitive mass penalties.
However, if the lifting provisions have to survive
much higher dynamic pressure during climb and acceleration,
then the aero structure can be quite heavy.

An exception was our 1971 "Windjammer" that became
the Boeing RASV. This type of space transport is
designed for horizontal takeoff, horizontal climb
and horizontal initial acceleration. Initial thrust-
to-system-mass might be only about 0.7--thereby saving
propulsion system mass and avoiding some of the aft
c.g. balancing problems in the empty condition. With
relieving load from LOX in the wings, wing mass might
only be about twice what it would be for LOX tanks
alone. This also results in low planform laoding with
resultant lower peak temperatures--which helps to attain
the required mass ratio and further reduces peak reentry
temperatures--etc.

Each design concept must adhere to a well integrated
design approach. There are different solutions, but
each approach must be well thought out with consistent
design philosophy. Superficial parametric studies--as
distinguished from detail design/analysis studies of
specific concepts--usually lead to misleading conclusions.
For example, some studies of HTOL vehicles have been made
by VTOL advocates who merely turned a VTO vehicle on its
side, added wings and made the system takeoff horizontally.
These studies were entirely misleading by not adjusting
T/W to proper values and by not taking advantage of such
aircraft-design concepts as relieving load, etc.

I have made other recent posts on this thread that seem
to have gotten lost.

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