Lobbing Passengers for fun and profit?

Hi all....

Just wondering....

If you were putting people in rockets and "lobbing" the passenger capsule from
the point of departure to the destination how much more fuel/energy would it
take than say flying in a 747? Or the Concorde? Or perhaps one of those
mythical Mach Mucho Grande.2 supersonic transports they seem to have made an
industry of designing but never building?

And I take it an Xprize kinda lob in the hundreds of miles range would be alot
easier (and more energy efficient) than one halfway around the world....and is
there a lob range that has a minimum fuel/energy cost per distance? Including
realistic accounting for drag and realistic mass fractions....

And lets ingore the practical aspects of cost effective rockets, and people
bitching about the noise from the rocket...and maybe even allow some pretty
high G forces if neccessary...and reuseable isnt a requirement either...

Now, the rocket can be multistaged if necessary, or perhaps dropped from a
transport plane...and maybe even first stage is powered by ground lasers....or
maybe first/zeroth stage is just a bunch of jet engines/pulsejets clustered
together ...but no rail/mass driver launches please

And of course your allowed to "fly" "outside" the atmosphere....but once
initial boost phase is over....its just minor course corrections to hit the
landing pad down range....

And I imagine that larger rockets would allow a larger percentage of mass to
actually be paying/praying passengers....and we can allow composite/advanced
materials that can save wieght.....but only stuff that can manufactured
now....in other words lets keep the mass fractions reasonable...

Sof the fuel/energy cost is always more...but how much more is it? 3x, 20x than
transport method XYZ but for distance 123 its 456 times faster kinda thing.....

And lets of course not "lobb" more than halfway around the world to keep this
"practical"

And I guess there is the point of _energy_ used vs fuel/oxidizer used vs cost
of energy as function of method of storage and extraction since the airplanes
dont carry the oxidizer etc etc....

So, perhaps something along the lines of it would cost a single passenger 50
dollars worth of fuel to fly 400 miles in a 747 but 5000 dollars worth of
fuel/oxidizer to be lobbed the same distance etc etc

take care

Blll

It only seems logical that getting out of the atmosphere and leaving drag
behind would have it's advantages, at least if we're talking about flights
roughly halfway around the world. But I've heard people say that the amount
of energy involved in achieving the necessary delta-V is greater than the
amount of energy needed to push the air out of the way at a more modest
velocity.

--


Regards,
Mike Combs
----------------------------------------------------------------------
We should ask, critically and with appeal to the numbers, whether the
best site for a growing advancing industrial society is Earth, the
Moon, Mars, some other planet, or somewhere else entirely.
Surprisingly, the answer will be inescapable - the best site is
"somewhere else entirely."

Gerard O'Neill - "The High Frontier"

(BllFs6) wrote in message ...
If you were putting people in rockets and "lobbing" the passenger capsule from
the point of departure to the destination how much more fuel/energy would it
take than say flying in a 747?

Well, from the rocket's point of view, you essentially need an orbit
capable rocket to do that. Roughly 85% of an orbital rocket is fuel,
and just 2% is payload.

I don't have the figures off-hand for a 747 going that distance, I
suggest you look on the Boeing website. You'd have to stop several
times.

Or the Concorde?

Concorde would use maybe 3x the fuel that a 747 takes.

And I take it an Xprize kinda lob in the hundreds of miles range would be alot
easier (and more energy efficient) than one halfway around the world....

No, the efficiency is better for a rocket at greater distance- the
efficiency of rockets goes up because it has no air drag at altitude
and it is near orbital speed, so the horizon falls away at much the
same rate as the vehicle is moving. An aeroplane is fighting drag all
the way. IRC the aeroplane still wins, but it would depend on the
aeroplane and the rocket. The rocket certainly gets you there much,
much faster though.

and is
there a lob range that has a minimum fuel/energy cost per distance?

Yup. Multiple times around the earth :-)

Blll

...
Well, from the rocket's point of view, you essentially need an orbit
capable rocket to do that. Roughly 85% of an orbital rocket is fuel,
and just 2% is payload.

I don't have the figures off-hand for a 747 going that distance, I
suggest you look on the Boeing website. You'd have to stop several
times.

Or the Concorde?

Concorde would use maybe 3x the fuel that a 747 takes.

And I take it an Xprize kinda lob in the hundreds of miles range would be alot

My humble understanding is that a 747 has a thrust of about 100 t, a
payload of about 100 tons, and a gross takeoff weight of about 400
tons. This makes it more fuel efficient than a rocket but at a much
slower speed. There are of course many different 747 variants.

Zoltan