On a Wing and a Catapult

Scratch the stilt wheels

Rutan's white knight has to have a ground clearence greater than
the height of the rocket it carries and take off requires greater
thrust than climbing to altitude. This looks like a job for a
specialized catapult. Elevated tracks on two bridge structures,
perhaps a mile long. Even a parallel stage could be accomidated. The
aircraft could land conventionally or perhaps be guided to and caught
by the same carriages that accelerated it.

In article ,
Old Physics wrote:
...This looks like a job for a
specialized catapult. Elevated tracks on two bridge structures,
perhaps a mile long. Even a parallel stage could be accomidated. The
aircraft could land conventionally or perhaps be guided to and caught
by the same carriages that accelerated it.

And if you have to abort without dropping the upper stage...?

To say nothing of the capital cost involved. This would make sense only
if a tremendous number of launches were planned... but in that case, abort
modes become a very serious consideration. For a handful of flights with
test pilots and volunteers, you can take your chances to some degree; for
a busy commercial service, intact abort at any time with an absolute
minimum of assumptions is mandatory.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

From article , by (Old Physics):

Rutan's white knight has to have a ground clearence greater than
the height of the rocket it carries and take off requires greater
thrust than climbing to altitude. This looks like a job for a
specialized catapult.

How is a mile long catapult any easier, cheaper, or better than just
building bigger landing gear?

(Steve VanSickle) wrote in message ...
From article , by (Old Physics):

Rutan's white knight has to have a ground clearence greater than
the height of the rocket it carries and take off requires greater
thrust than climbing to altitude. This looks like a job for a
specialized catapult.

How is a mile long catapult any easier, cheaper, or better than just
building bigger landing gear?

The pegasus rocket weighs just over twenty tons and requires a B52
or heavy airliner to loft it. Do you really think that a carrier
aircraft, in this weight class, could be designed with landing gear
extended by 20 feet, with enough clearence to accomidate a 100 ton
booster?

(Henry Spencer) wrote in message ...
In article ,
Old Physics wrote:
...This looks like a job for a
specialized catapult. Elevated tracks on two bridge structures,
perhaps a mile long. Even a parallel stage could be accomidated. The
aircraft could land conventionally or perhaps be guided to and caught
by the same carriages that accelerated it.

And if you have to abort without dropping the upper stage...?

To say nothing of the capital cost involved. This would make sense only
if a tremendous number of launches were planned... but in that case, abort
modes become a very serious consideration. For a handful of flights with
test pilots and volunteers, you can take your chances to some degree; for
a busy commercial service, intact abort at any time with an absolute
minimum of assumptions is mandatory.

Parallel stages launched this way may be a streach. A 100 ton
booster might be expected to have a payload of two tons to LEO. The
aircraft that lofts the rocket doesn't have to have a center fuselage,
it might weigh less than the booster, which can have independent
structural integrity.
The catapult system could probably be built for under a billion
dollars, less than the cost of putting 60 tons into space via the
shuttle. It might break even after fifty launches.
Safety would limit it to unmanned payloads until its reliability
is established. If costs were brought down to under $1000 a pound
there might be a market for earth viewing, virtual presense, cameras
and real time orbital views to push advertising. Maybe 300
satellites, at various altitudes, totaling 60 tons.
Rock samples from exploration missions to the moon and asteroids
might have a market of several billion, with effective hype, if the
cost were under $30 per gram. Industry might show an interest if
experimental equipment could be launched frequently and cheaply.
Probably too many ifs. My point is that this would be a practical
way to scale up the pegasus-scaled composites concept.
What do you think of the marketing possibilities of any system
that could put 100 tons per year into LEO, in two ton lots, for under
$1000/lb? If the capability existed could it be profitable?
Extreme thanks for your expertise.

Or... the next, bigger one will ride on top of the carrier instead, keping the
landing gear height and ground clearance reasonable, but requiring some kind of
derrick arrangement like the shuttle's mate/de-mate device...

or... crafty as the Great Sideburns is, he might figure a way to wrap the
carrier craft around/ to either side of the spacecraft... maybe something in
the same general family as the Boomerang or Pond Racer layouts. Whatever it
is, it will be weird yet cool.

In article ,
Old Physics wrote:
How is a mile long catapult any easier, cheaper, or better than just
building bigger landing gear?

The pegasus rocket weighs just over twenty tons and requires a B52
or heavy airliner to loft it. Do you really think that a carrier
aircraft, in this weight class, could be designed with landing gear
extended by 20 feet, with enough clearence to accomidate a 100 ton
booster?

If you must do a new design, it would be a sizable project, but far from
impossible. Almost certainly it would cost less than the catapult.

Bear in mind that it doesn't have to be an all-new design. Boeing has
long been interested in building super-heavy cargo derivatives of the 747.
One idea for that had a pair of 747 fuselages connected with a short
*high* wing, so a big external payload could be carried between them.

For that matter, if you're willing to launch off the *top* of a 747, you
don't need a new aircraft at all. A 747 can already carry about that.

(A data point of interest is that Grumman's proposal to the SDIO SSTO
program -- the program that produced DC-X -- used air launch from a 747,
with existing engines and aluminum structure, and put 4-5t into LEO for
an estimated total development bill of under $1G.)
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

(Old Physics) :

(Steve VanSickle) wrote in message
...
From article , by
(Old Physics):

Rutan's white knight has to have a ground clearence greater than
the height of the rocket it carries and take off requires greater
thrust than climbing to altitude. This looks like a job for a
specialized catapult.

How is a mile long catapult any easier, cheaper, or better than just
building bigger landing gear?

The pegasus rocket weighs just over twenty tons and requires a B52
or heavy airliner to loft it. Do you really think that a carrier
aircraft, in this weight class, could be designed with landing gear
extended by 20 feet, with enough clearence to accomidate a 100 ton
booster?

No, two reasons. B.R. is a lot smarter than you and would not demand that
the next size up needs to be a 100 ton booster! Where did you come with that
number? Second a B52 is a very heavy plane by itself. If I remember right
the carrier craft was lighter that the fully loaded/fueled SS1 and it basicly
is just wings/landing gear/jet engines and pilot space, A larger carrier
designed by BR would carry far more wieght and still be a fraction of the
mass of a B52.

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

BTW, I read somewhere that B-52's are so heavy that they can't operate on many
runways and taxiways of current non-military airports unless mostly de-fueld
first, else they'd crack the concrete.

"MSu1049321" wrote in message
...
BTW, I read somewhere that B-52's are so heavy that they can't operate on
many
runways and taxiways of current non-military airports unless mostly
de-fueld
first, else they'd crack the concrete.

Well, http://www.af.mil/factsheets/factsheet.asp?fsID=83 lists the max
takeoff weight as 488,000 lbs and
http://www.boeing.com/commercial/747...00er_back.html lists the
747-400ER takeoff weight as 910,000lbs.

So I don't think that's true.