A kerosene-fueled X-33 as a single stage to orbit vehicle.

In article , lid
says...

sigh It's not a rocket in airbreathing mode.

It's some ******* engine that does nothing well. It's not as efficient
as a turbofan (likely even a turbojet) aircraft engine when in air-
breathing mode and it's not as efficient as a liquid fueled rocket
engine when operating in pure rocket mode (LOX from internal tanks).

I fail to see how an engine which operates worse than the state of the
art in either mode is better than having two separate stages with two
separate types of engines on each.

All of this silliness is in pursuit of SSTO. Fully reusable TSTO would
be far easier to implement than this because it would require no new
technologies (i.e. fundamentally new engine) to be developed.

Jeff
--
" Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry
Spencer 1/28/2011

On 7/14/2011 6:30 AM, Jeff Findley wrote:


All of this silliness is in pursuit of SSTO. Fully reusable TSTO would
be far easier to implement than this because it would require no new
technologies (i.e. fundamentally new engine) to be developed.


I can't see why Lockheed didn't just take their VentureStar design and
stick a "V" shaped drop tank on it like there 1960's Star Clipper design
was going to use. Since the VentureStar design was only failing
marginally as a SSTO, the external tankage wouldn't need be that large,
and you would have just eliminated the need for the Shuttle's large
SRB's, and would only be losing the fairly cheap drop tank on each mission.

Pat

On Jul 14, 12:57*pm, Pat Flannery wrote:
On 7/14/2011 6:30 AM, Jeff Findley wrote:


All of this silliness is in pursuit of SSTO. *Fully reusable TSTO would
be far easier to implement than this because it would require no new
technologies (i.e. fundamentally new engine) to be developed.

I can't see why Lockheed didn't just take their VentureStar design and
stick a "V" shaped drop tank on it like there 1960's Star Clipper design
was going to use. Since the VentureStar design was only failing
marginally as a SSTO, the external tankage wouldn't need be that large,
and you would have just eliminated the need for the Shuttle's large
SRB's, and would only be losing the fairly cheap drop tank on each mission.

On Jul 14, 3:57*pm, Pat Flannery wrote:
On 7/14/2011 6:30 AM, Jeff Findley wrote:



All of this silliness is in pursuit of SSTO. *Fully reusable TSTO would
be far easier to implement than this because it would require no new
technologies (i.e. fundamentally new engine) to be developed.

I can't see why Lockheed didn't just take their VentureStar design and
stick a "V" shaped drop tank on it like there 1960's Star Clipper design
was going to use. Since the VentureStar design was only failing
marginally as a SSTO, the external tankage wouldn't need be that large,
and you would have just eliminated the need for the Shuttle's large
SRB's, and would only be losing the fairly cheap drop tank on each mission.

On 15/07/2011 12:30 AM, Jeff Findley wrote:
In , lid
says...

sigh It's not a rocket in airbreathing mode.

It's some ******* engine that does nothing well. It's not as efficient
as a turbofan (likely even a turbojet) aircraft engine when in air-
breathing mode and it's not as efficient as a liquid fueled rocket
engine when operating in pure rocket mode (LOX from internal tanks).

I fail to see how an engine which operates worse than the state of the
art in either mode is better than having two separate stages with two
separate types of engines on each.

All of this silliness is in pursuit of SSTO. Fully reusable TSTO would
be far easier to implement than this because it would require no new
technologies (i.e. fundamentally new engine) to be developed.

It's all about cost per kg payload in orbit. An SSTO, particularly one
that takes off and lands horizontally presents considerable operational
advantages.

While the SABRE engine is more complex than a standard rocket,
complexity is removed in other areas - there's no stage separation, for
example. It also eliminates a whole class of risks associated with
separation, such as collisions between the two parts of the vehicle,
partial separation, etc.

In any case, it's far from clear that a fully reusable TSTO is so easy
to achieve.

Getting Skylon to work in practice may prove more difficult than RE
think. It may prove impossible. But I don't understand the sheer
antagonism towards it evidenced by some in this group. Unless it's a
manifestation of a fear that RE will achieve a disruptive technology.

http://en.wikipedia.org/wiki/Disruptive_technology

Sylvia.

In article , lid
says...

On 15/07/2011 12:30 AM, Jeff Findley wrote:
In , lid
says...

sigh It's not a rocket in airbreathing mode.

It's some ******* engine that does nothing well. It's not as efficient
as a turbofan (likely even a turbojet) aircraft engine when in air-
breathing mode and it's not as efficient as a liquid fueled rocket
engine when operating in pure rocket mode (LOX from internal tanks).

I fail to see how an engine which operates worse than the state of the
art in either mode is better than having two separate stages with two
separate types of engines on each.

All of this silliness is in pursuit of SSTO. Fully reusable TSTO would
be far easier to implement than this because it would require no new
technologies (i.e. fundamentally new engine) to be developed.

It's all about cost per kg payload in orbit. An SSTO, particularly one
that takes off and lands horizontally presents considerable operational
advantages.

Please enumerate the advantages of HTHL over VTVL as they apply to SSTO.
At this point in time, I'm simply not convinced that the advantages are
worth the cost, especially for intact abort scenarios.

While the SABRE engine is more complex than a standard rocket,
complexity is removed in other areas - there's no stage separation, for
example.

Stage separation is an existing technology that's been in place on the
very first orbital launch vehicle. It's at least a fairly well known
quantity, especially if you do your stage separation above the bulk of
the atmosphere.

It also eliminates a whole class of risks associated with
separation, such as collisions between the two parts of the vehicle,
partial separation, etc.

A VTVL SSTO would have the same advantages without the high cost of
SABRE development.

In any case, it's far from clear that a fully reusable TSTO is so easy
to achieve.

Possibly, but so far, no one has tried to build and fly such a vehicle.
It's at least on firmer technological ground than SABRE and Skylon, so
I'd say the chance of success would be much higher for the reusable
TSTO.

Getting Skylon to work in practice may prove more difficult than RE
think. It may prove impossible. But I don't understand the sheer
antagonism towards it evidenced by some in this group. Unless it's a
manifestation of a fear that RE will achieve a disruptive technology.

No, it's mostly the acknowledgment that SABRE is a bleeding edge
technology in much the same way as a hypersonic air breathing engine
(e.g. NASP and more recent technology demonstrators). We've been down
this road more than once, and it's burned us each and every time.

Don't get me wrong, I'd really *like* to see Reaction Engines succeed
and produce a working, economically viable, launch vehicle. I'm just
extremely skeptical due to the inclusion of an engine design which has
never been fully tested *and* has not been successfully integrated into
an actual vehicle.

Aerodynamics is a p.i.t.a. and it will rear its ugly head during the
design phase where the engine is integrated into a *real* vehicle. So
far, I find the "artist's concept" type drawings of Skylon to be lacking
in sufficient aerodynamic detail. In order to provide enough air for
the engines at flight conditions, the engine will need to be *much* more
integrated into the vehicle aerodynamics than current drawings and
renderings suggest.

This should come as no surprise since Reaction Engines is focusing on
building a working engine first. The problem is still that of the
chicken and egg. Without an engine fully integrated into an actual
vehicle, it's awfully hard to test either the engine or the vehicle.
Due to the nature of the engine (and the aerodynamics needed for the
inlet), the two designs are almost inseparable.

Jeff
--
" Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry
Spencer 1/28/2011

On 7/15/2011 6:23 AM, Jeff Findley wrote:

No, it's mostly the acknowledgment that SABRE is a bleeding edge
technology in much the same way as a hypersonic air breathing engine
(e.g. NASP and more recent technology demonstrators). We've been down
this road more than once, and it's burned us each and every time.

In the case of the NASP/Copper Canyon, the scramjet technology may have
been at least partially a chimera, to mislead the Soviets and drive them
to the bargaining table.

Pat

"Pat Flannery" wrote:
-- Jeff Findley wrote:

Jeff wrote:
No, it's mostly the acknowledgment that SABRE is a bleeding edge
technology in much the same way as a hypersonic air breathing engine
(e.g. NASP and more recent technology demonstrators). We've been down
this road more than once, and it's burned us each and every time.

Pat wrote:
In the case of the NASP/Copper Canyon, the scramjet technology may have
been at least partially a chimera, to mislead the Soviets and drive them
to the bargaining table.

hanson wrote:
http://www.physorg.com/news/2011-03-experimental-scramjet-aircraft-flight.html
There is this X-51 thing that superceded the Aurora stuff
SR-91 (Not 71), http://www.fas.org/irp/mystery/aurora.htm
which back in July 1998 stirred up controversy when it went
over LA to land at Edwards, producing 2 sonicbooms and
showing a pearl-chain-like exhaust vapor trail.

These are all apparently descendants and supersonic
versions of the 1944 Nazi version of the Buzz bomb
http://en.wikipedia.org/wiki/V-1_flying_bomb

Price tag for $/Speed though, is not exactly linear... ahahaha...
Also, whether that did or not intermesh with Soviet technology
or their intents is another story, but it certainly creates great
lore and lure... ahahahaha...

On Jul 15, 12:23*pm, "hanson" wrote:
"Pat Flannery" wrote:

*-- Jeff Findley wrote:

Jeff wrote:
No, it's mostly the acknowledgment that SABRE is a bleeding edge
technology in much the same way as a hypersonic air breathing engine
(e.g. NASP and more recent technology demonstrators). *We've been down
this road more than once, and it's burned us each and every time.

Pat wrote:
In the case of the NASP/Copper Canyon, the scramjet technology may have
been at least partially a chimera, to mislead the Soviets and drive them
to the bargaining table.

hanson wrote:

http://www.physorg.com/news/2011-03-experimental-scramjet-aircraft-fl...
There is this X-51 thing that superceded the Aurora stuff
SR-91 (Not 71), http://www.fas.org/irp/mystery/aurora.htm
which back in July 1998 stirred up controversy when it went
over LA to land at Edwards, producing 2 sonicbooms and
showing a pearl-chain-like exhaust vapor trail.

These are all apparently descendants and supersonic
versions of the 1944 Nazi version of the Buzz bomb
http://en.wikipedia.org/wiki/V-1_flying_bomb

Price tag for $/Speed though, is not exactly linear... ahahaha...
Also, whether that did or not intermesh with Soviet technology
or their intents is another story, but it certainly creates great
lore and lure... ahahahaha...

I learned propulsion from Von Eschen, who worked on the V-1.
Intermittent combustion with valved operation has its own limitations
which give it limited speeds as well.

Slowing the air imposes a huge drag. Injecting hydrogen into the air
stream and creating a structure wave to ride, does not.

In sci.space.history Jeff Findley wrote:

Stage separation is an existing technology that's been in place on
the very first orbital launch vehicle. It's at least a fairly well
known quantity, especially if you do your stage separation above the
bulk of the atmosphere.

I'll simply toss some shells from the peanut gallery not meant to
suggest favoring one side of the other... And yet even in 2010 (or was
it 2009) SpaceX still had their stages bump

rick jones
--
No need to believe in either side, or any side. There is no cause.
There's only yourself. The belief is in your own precision. - Joubert
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...