Long cables to power "ioncraft" to orbit?

Robert Clark

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May 17, 2005, 3:53:31 PM5/17/05

to

The ioncraft is a method proposed for decades for aircraft and
spacecraft propulsion:

Ioncraft.
http://www.markwilson.com/ioncraft/ioncraft.html

It works by ionizing the air by electrical charge thereby creating an
air flow between the electrodes, generating thrust. There are several
examples of these, called "lifters", made by amateurs:

The Lifters Experiments home page by Jean-Louis Naudin.
http://jnaudin.free.fr/lifters/main.htm

The problem with them is their power supplies are much heavy than the
weight they can lift. But why not leave the power supply on the ground
and connect it to the craft by long power cables?

There are carbon fibers that could support their own weight up to
hundreds of kilometer of altitude:

Carbon fiber (Dani Eder)
http://yarchive.net/space/exotic/carbon_fiber.html

And power transmission lines carry electrical power up to 250km away
at up to 600 megawatts of power:

Baltic-Cable.
http://www.answers.com/topic/baltic-cable?method=5

This page calculates you can lift 3.91 grams using 7.681 watts of
power or about a ratio of 1 to 2:

Lifter Theory.
http://jnaudin.free.fr/html/lftheory.htm

Then you could lift 1,000,000 kg using 2 gigawatts of power. The space
shuttle main engines produce a maximum of 37 million horsepower, or
27.6 gigawatts of power:

Boeing: Rocketdyne: Space Shuttle Main Engine Amazing Facts.
http://www.boeing.com/defense-space/space/propul/SSMEamaz.html

Then you could leave the large heavy engines and heavy fuel on the
ground and use it just to run electrical generators to drive the
ioncraft.
If the electrical cable was 4 cm wide made of carbon fiber, a 100km
long cable would have volume Pi*.02^2*100000 = 125.7m^3. At a density
of 1800 kg/m^3 for carbon fiber this would be 226,000 kg. Then twice
this number in kilowatts or 452 megawatts would be needed to support
the weight of the wire alone. You could have take this from the 10's of
gigawatts supplied to the ioncraft or have small versions of the lifter
drive all along the length of the power cable itself drawing off some
portion of the power to support each small portion of the cable.
The question: how much power would be lost by sending it along a 100km
long cable?

Bob Clark

Charles Jean

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May 17, 2005, 5:52:36 PM5/17/05

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On Tue, 17 May 2005 22:21:34 +0100, "George Dishman"
<geo...@briar.demon.co.uk> wrote:

>
>"Robert Clark" <rgrego...@yahoo.com> wrote in message
>news:1116359611....@g47g2000cwa.googlegroups.com...

>
>> The question: how much power would be lost by
>> sending it along a 100km long cable?
>

>Choose your voltage. Divide power P by voltage V to
>get current I. Loss is I^2 * R. You need to work
>out R using the resistivity of the material and the
>length. Remember to count both wires.
>
>George
>

I assume you will be running two cables for the power, a hot and a
return. How about insulation of the wires from each other? Is the
conductor here the carbon fiber itself or some metal? Then calculate:
a) the total mass of 100,000 ft. of the cables
b) the electrical resistance of 100,000 ft. of the the conductors
c) power loss through the conductors
d) temperature rise through the conductors

"There are known knowns. These are things that we know we know.
There are known unknowns. That is to say, there are some
things that we know we don't know. But there are also unknown
unknowns. These are things we don't know we don't know."
-Secretary of Defense Donald Rumsfeld

George Dishman

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May 17, 2005, 5:21:34 PM5/17/05

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"Robert Clark" <rgrego...@yahoo.com> wrote in message
news:1116359611....@g47g2000cwa.googlegroups.com...

> The question: how much power would be lost by

> sending it along a 100km long cable?

Choose your voltage. Divide power P by voltage V to

Uncle Al

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May 17, 2005, 4:49:41 PM5/17/05

to

Robert Clark wrote:
>
> The ioncraft is a method proposed for decades for aircraft and
> spacecraft propulsion:

[snip]

> It works by ionizing the air by electrical charge thereby creating an
> air flow between the electrodes, generating thrust. There are several
> examples of these, called "lifters", made by amateurs:

[snip crap]

Hey stooopid, thrust in this case varies as surface area but payload
varies as volume. The demo is bullshit when applied to the real world
product.

> The problem with them is their power supplies are much heavy than the
> weight they can lift. But why not leave the power supply on the ground
> and connect it to the craft by long power cables?

[snip]

Dumber than a used tampon. Hey stooopid, rockets don't launch
straight up - not for long they don't. Getting 100 miles high is a
no-brainer. Scaled Composites mostly pulled it off ad hoc. Getting to
25,000 mph at 100 miles altitude is something else again.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

Luhan Monat

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May 17, 2005, 7:12:41 PM5/17/05

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>
> "There are known knowns. These are things that we know we know.
> There are known unknowns. That is to say, there are some
> things that we know we don't know. But there are also unknown
> unknowns. These are things we don't know we don't know."
> -Secretary of Defense Donald Rumsfeld

Rumsfeld must have taken EST. That was part of the course introduction.

--
Luhan Monat: luhanis(at)yahoo(dot)com
http://members.cox.net/berniekm
"Any sufficiently advanced magick is
indistinguishable from technology."

Jim Thompson

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May 17, 2005, 7:21:16 PM5/17/05

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On Tue, 17 May 2005 16:12:41 -0700, Luhan Monat <x@y.z> wrote:

>
>>
>> "There are known knowns. These are things that we know we know.
>> There are known unknowns. That is to say, there are some
>> things that we know we don't know. But there are also unknown
>> unknowns. These are things we don't know we don't know."
>> -Secretary of Defense Donald Rumsfeld
>
>Rumsfeld must have taken EST. That was part of the course introduction.

It's deja vu all over again ;-)

Rich Grise

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May 17, 2005, 7:39:04 PM5/17/05

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On Tue, 17 May 2005 12:53:31 -0700, Robert Clark wrote:

> The problem with them is their power supplies are much heavy than the
> weight they can lift. But why not leave the power supply on the ground and
> connect it to the craft by long power cables?

Because 100 miles of copper power cable is even heavier?

Thanks,
Rich

John Larkin

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May 17, 2005, 7:55:44 PM5/17/05

to

On Tue, 17 May 2005 16:12:41 -0700, Luhan Monat <x@y.z> wrote:

>
>>
>> "There are known knowns. These are things that we know we know.
>> There are known unknowns. That is to say, there are some
>> things that we know we don't know. But there are also unknown
>> unknowns. These are things we don't know we don't know."
>> -Secretary of Defense Donald Rumsfeld
>
>Rumsfeld must have taken EST. That was part of the course introduction.

We had a lot of them here. We called them estholes:

"Yes, I'm standing on your face, and I'm wearing cleats, but if you
really want to be miserable, it's your problem."

John

mme...@cars3.uchicago.edu

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May 17, 2005, 7:55:59 PM5/17/05

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I've been wondering how long it'll take before somebody states the
obvious.

Mati Meron | "When you argue with a fool,
me...@cars.uchicago.edu | chances are he is doing just the same"

Ben Bradley

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May 17, 2005, 9:07:17 PM5/17/05

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On Tue, 17 May 2005 23:39:04 GMT, Rich Grise <rich...@example.net>
wrote:

And at Monster Cable(TM)(R) prices it's hugely expensive.

>Thanks,
>Rich

-----
http://mindspring.com/~benbradley

Asimov

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May 17, 2005, 11:38:24 PM5/17/05

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"mme...@cars3.uchicago.edu" bravely wrote to "All" (17 May 05 23:55:59)
--- on the heady topic of "Re: Long cables to power "ioncraft" to orbit?"

mm> From: mme...@cars3.uchicago.edu
mm> Xref: aeinews sci.astro:60237 sci.space.policy:6441 sci.physics:206464
mm> sci.electronics.design:17243 sci.electronics.misc:19127
mm> In article <pan.2005.05.17....@example.net>, Rich Grise
mm> <rich...@example.net> writes: >On Tue, 17 May 2005 12:53:31 -0700,

mm> Robert Clark wrote: >
>> The problem with them is their power supplies are much heavy than the
>> weight they can lift. But why not leave the power supply on the ground and
>> connect it to the craft by long power cables?
>
>Because 100 miles of copper power cable is even heavier?
>

mm> I've been wondering how long it'll take before somebody states the
mm> obvious.

No problem is too big for nuclear power! Forget the cables, use some
fissile materials.

BTW wasn't 2 gigawatts the amount of power used by the flux capacitor
in Back to the Future's Delorean?

A*s*i*m*o*v

... I had a monumental idea this morning, but I didn't like it.

rgrego...@yahoo.com

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May 18, 2005, 1:20:55 AM5/18/05

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Aluminum is almost always used for high voltage power lines. This is
because of its lower weight:

Aluminium's Electrical Uses.
http://www.world-aluminium.org/applications/electrical/

At 2700 kg/m^3, it's weight is only 50% more than carbon fiber. So a 4
cm wide, 100km long aluminum cable would only weigh 340,000 kg. This
compares to 2 million kg for the space shuttle with solid rocket
boosters.
While carbon fiber is electrically conductive, you might want to use
aluminum for higher conductivity (lower power loss). Then you would use
carbon fiber to provide strength for the cable.

Bob Clark

Ban

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May 18, 2005, 1:23:46 AM5/18/05

to

Robert Clark wrote:
snip childish BS
I remember being 13yrs. old and discussing things like this with my
roommates at public school. It is a nice exercise being kids, but a grown up
person should switch on the probability check before x-posting to all these
NGs.
--
ciao Ban
Bordighera, Italy

bz

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May 18, 2005, 3:56:22 AM5/18/05

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rgrego...@yahoo.com wrote in news:1116393655.205094.108590
@f14g2000cwb.googlegroups.com:

How much current is going to flow? If those aluminum wires are 3 cm in
diameter, the resistance of two 100 km wires is going to be about 750 ohms.

Most of your power is going to end up heating your wire.

--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz...@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap

GWBush

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May 18, 2005, 8:45:08 AM5/18/05

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On Wed, 18 May 2005 05:23:46 GMT, "Ban" <ban...@web.de> wrote:

>Robert Clark wrote:
>snip childish BS
>I remember being 13yrs. old and discussing things like this with my
>roommates at public school. It is a nice exercise being kids, but a grown up
>person should switch on the probability check before x-posting to all these
>NGs.

You are assuming that these peopleare grown-up and mature to start.

dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)

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May 18, 2005, 9:04:28 AM5/18/05

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Dear Asimov:

"Asimov" <Asimov@-removethis-bbs.juxtaposition.dynip.com> wrote
in message news:MSGID_1=3a167=2f133.0_...@fidonet.org...

> "mme...@cars3.uchicago.edu" bravely wrote to "All" (17 May 05
> 23:55:59)
> --- on the heady topic of "Re: Long cables to power "ioncraft"
> to orbit?"

...

> mm> I've been wondering how long it'll take before

> mm> somebody states the obvious.

>
> No problem is too big for nuclear power! Forget
> the cables, use some fissile materials.
>
> BTW wasn't 2 gigawatts the amount of power
> used by the flux capacitor in Back to the Future's
> Delorean?

1.21 gigawatts.

David A. Smith

Robert Clark

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May 18, 2005, 9:18:22 AM5/18/05

to

This page gives the resistance over 200 km for a 3 cm diameter cable
as only 7.9 ohms:

Electric Current.
"A high voltage transmission line has an aluminum cable of diameter
3.0cm, 200km long. What is the resistance of this cable? Solution:
The resistivity of aluminum is 2.8*10^(-8)ohm-m. the length of the
cable is 2*10^5m. The diameter of the cable is 3cm and its
cross-sectional area is equal to Pi*(d/2)^2 or 7.1*10^(-4) m^2.
Substituting these values into R = rL/A the resistance of the cable can
be determined.
R = (2.8*10^(-8)*2*10^5)/( 7.1*10^(-4)) = 7.9 ohms".
http://electron9.phys.utk.edu/phys136d/modules/m6/current.htm

For a wider cable the resistance will be less in proportion to the
cross-sectional area.

Bob Clark

bz

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May 18, 2005, 9:46:26 AM5/18/05

to

"Robert Clark" <rgrego...@yahoo.com> wrote in

news:1116422302....@g47g2000cwa.googlegroups.com:

> This page gives the resistance over 200 km for a 3 cm diameter cable
> as only 7.9 ohms:
>
> Electric Current.
> "A high voltage transmission line has an aluminum cable of diameter
> 3.0cm, 200km long. What is the resistance of this cable? Solution:
> The resistivity of aluminum is 2.8*10^(-8)ohm-m. the length of the
> cable is 2*10^5m. The diameter of the cable is 3cm and its
> cross-sectional area is equal to Pi*(d/2)^2 or 7.1*10^(-4) m^2.
> Substituting these values into R = rL/A the resistance of the cable can
> be determined.
> R = (2.8*10^(-8)*2*10^5)/( 7.1*10^(-4)) = 7.9 ohms".
> http://electron9.phys.utk.edu/phys136d/modules/m6/current.htm
>
> For a wider cable the resistance will be less in proportion to the
> cross-sectional area.
>
>

You are correct.

The discrepancy is in this figure: 2.8*10^(-8) ohm meter
Mathcad has 2.655 x 10^-6 ohm cm.

I used 2.655e-6 ohm meters!

I didn't look at the units closely enough.

I should have said 7.512 ohms for two 3 cm wires.

Luhan Monat

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May 18, 2005, 10:14:54 AM5/18/05

to

John Larkin wrote:
>
> We had a lot of them here. We called them estholes:
>
> "Yes, I'm standing on your face, and I'm wearing cleats, but if you
> really want to be miserable, it's your problem."
>

Some friends of mine who did EST long before I did, already used the
term 'estholes' themselves.

Ed Kyle

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May 18, 2005, 11:13:25 AM5/18/05

to

Not to mention all of the untangling that would be
required after each launch. :)

- Ed Kyle

Eric Chomko

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May 18, 2005, 12:13:28 PM5/18/05

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Charles Jean (alch...@earthlink.net) wrote:
: On Tue, 17 May 2005 22:21:34 +0100, "George Dishman"
: <geo...@briar.demon.co.uk> wrote:

Makes me think of the little passage from the Koran I think:

He who knows not and knows he knows not is simple, teach him,
He who knows and knows not he knows is asleep, awaken him,
He who knows not and knows not he knows not is a fool, shun him,
He who knows and knows he knows is a leader, follow him.

Eric

Stephen Horgan

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May 18, 2005, 2:49:05 PM5/18/05

to

On 17 May 2005 12:53:31 -0700, "Robert Clark"
<rgrego...@yahoo.com> wrote:

Leaving aside the engineering problems, you have to get to escape
velocity to make orbit and at altitude you run out of air to ionise.
--
Stephen Horgan

"intelligent people will tend to overvalue intelligence"

Dirk Bruere at Neopax

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May 18, 2005, 2:50:46 PM5/18/05

to

Robert Clark wrote:

> The ioncraft is a method proposed for decades for aircraft and
> spacecraft propulsion:
>
> Ioncraft.
> http://www.markwilson.com/ioncraft/ioncraft.html
>
> It works by ionizing the air by electrical charge thereby creating an
> air flow between the electrodes, generating thrust. There are several
> examples of these, called "lifters", made by amateurs:
>
> The Lifters Experiments home page by Jean-Louis Naudin.
> http://jnaudin.free.fr/lifters/main.htm
>
> The problem with them is their power supplies are much heavy than the
> weight they can lift. But why not leave the power supply on the ground
> and connect it to the craft by long power cables?
>
> There are carbon fibers that could support their own weight up to
> hundreds of kilometer of altitude:
>
> Carbon fiber (Dani Eder)

> http://yarchive.net/space/exot虹c/carbon_fiber.html

Use a uwave beam and onboard rectenna

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org

Keith Williams

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May 18, 2005, 3:08:24 PM5/18/05

to

In article <t73n81de3sh6at67s...@4ax.com>,
ste...@horgan.REMOVETOREPLY.co.uk says...

> On 17 May 2005 12:53:31 -0700, "Robert Clark"
> <rgrego...@yahoo.com> wrote:
>
> > The ioncraft is a method proposed for decades for aircraft and
> >spacecraft propulsion:
> >
> >Ioncraft.
> >http://www.markwilson.com/ioncraft/ioncraft.html
> >
> > It works by ionizing the air by electrical charge thereby creating an
> >air flow between the electrodes, generating thrust. There are several
> >examples of these, called "lifters", made by amateurs:
> >
> >The Lifters Experiments home page by Jean-Louis Naudin.
> >http://jnaudin.free.fr/lifters/main.htm
> >
> > The problem with them is their power supplies are much heavy than the
> >weight they can lift. But why not leave the power supply on the ground
> >and connect it to the craft by long power cables?
> >
> > There are carbon fibers that could support their own weight up to
> >hundreds of kilometer of altitude:
> >
> >Carbon fiber (Dani Eder)

> >http://yarchive.net/space/exot虹c/carbon_fiber.html

Umm, if you achieve escape velocity you , err, escape (I.e. you've
overachieved)

--
Keith

tadchem

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May 18, 2005, 4:01:41 PM5/18/05

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Charles Jean wrote:

<snip>

> "There are known knowns. These are things that we know we know.
> There are known unknowns. That is to say, there are some
> things that we know we don't know. But there are also unknown
> unknowns. These are things we don't know we don't know."
> -Secretary of Defense Donald Rumsfeld

If Rummy really said this, then he is much more widely read than I
would have believed. This is a variation of a quotation from Lady
Burton, attributed as an 'Arabian Proverb':
"Men are four:
He who knows not and knows not he knows not, he is a fool--shun him;
He who knows not and knows he knows not, he is simple--teach him;
He who knows and knows not he knows, he is asleep--wake him;
He who knows and knows he knows, he is wise--follow him!"

Tom Davidson
Richmond, VA

mme...@cars3.uchicago.edu

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May 18, 2005, 5:08:22 PM5/18/05

to

In article <1116446501.8...@f14g2000cwb.googlegroups.com>, "tadchem" <thomas....@dla.mil> writes:
>
>Charles Jean wrote:
>
><snip>
>
>> "There are known knowns. These are things that we know we know.
>> There are known unknowns. That is to say, there are some
>> things that we know we don't know. But there are also unknown
>> unknowns. These are things we don't know we don't know."
>> -Secretary of Defense Donald Rumsfeld
>
>If Rummy really said this,

He did.

> then he is much more widely read than I
>would have believed. This is a variation of a quotation from Lady
>Burton, attributed as an 'Arabian Proverb':
>"Men are four:
>He who knows not and knows not he knows not, he is a fool--shun him;
>He who knows not and knows he knows not, he is simple--teach him;
>He who knows and knows not he knows, he is asleep--wake him;
>He who knows and knows he knows, he is wise--follow him!"
>

Yep. Closer to home, note that the first category above is endowed
with what we (meaning sci.physics regulars) refer to as "second order
ignorance", which is the characteristic of many of our cranks.

Anyway, Rummy did say this and many seemingly intelligent people
jumped on this as a "dumb statement", not realizing that it was their
own stupidity they were thus proclaiming.

bz

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May 18, 2005, 6:11:57 PM5/18/05

to

Dirk Bruere at Neopax <di...@neopax.com> wrote in news:3f1h43F4q4r6U1
@individual.net:

> If the electrical cable was 4 cm wide made of carbon fiber, a 100km
>> long cable would have volume Pi*.02^2*100000 = 125.7m^3. At a density
>> of 1800 kg/m^3 for carbon fiber this would be 226,000 kg. Then twice
>> this number in kilowatts or 452 megawatts would be needed to support
>> the weight of the wire alone. You could have take this from the 10's of
>> gigawatts supplied to the ioncraft or have small versions of the lifter
>> drive all along the length of the power cable itself drawing off some
>> portion of the power to support each small portion of the cable.
>> The question: how much power would be lost by sending it along a 100km
>> long cable?

The working model apparently requires 30 kV to generate the ions.

That implies that you need pretty good insulation on your cables.
You need to take that into account.

Neglecting that weight, (assume we can put a few spacers between the wires
and their weigh will be negligible, for now) the 452 MW will require 15 kA.
15 thousand amps through the 7.5 ohms (that was from 3 cm diameter aluminum
wires, so the weight we need to lift is underestimated by a significant
factor, but it doesn't really matter, as you will see) of the wires will
drop 113 kV.

The power supply will thus need to put out 133 kV.
From this, it should be clear that MOST of the energy will go to heating
the wires. The wire will disipate 1.6 GW and 0.45 GW goes for lifting the
wire itself. The weight of the payload is negligible compared to the wire.

The wires are going to need to be able to dissipate 254 watts for each 3 cm
of length without weakening. I think the 3 cm diameter wire can take it.

Oh, there is one other 'minor' problem.
This craft will only work inside the atmosphere because it uses the motion
of air molecules to do the lifting.

The lift will fall off with altitude.

So, you don't need to worry about lifting 100 km of wire. It can probably
only go to a few hundred thousand feet.

One other minor problem. When it does get up high, it is going to contact
some layers of the atmospher that carry high charges wrt ground.

Of course, you may be able to get back much more energy than the lift took.

CWatters

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May 19, 2005, 3:09:34 AM5/19/05

to

"Robert Clark" <rgrego...@yahoo.com> wrote in message
news:1116359611....@g47g2000cwa.googlegroups.com...

> It works by ionizing the air by electrical charge thereby
> creating an air flow between the electrodes, generating
> thrust.

unread,

May 19, 2005, 1:39:28 PM5/19/05

to

On Wed, 18 May 2005 15:08:24 -0400, Keith Williams wrote:
> In article <t73n81de3sh6at67s...@4ax.com>,
> ste...@horgan.REMOVETOREPLY.co.uk says...
>> On 17 May 2005 12:53:31 -0700, "Robert Clark" <rgrego...@yahoo.com>
>> wrote:

[some fantasy]

>> Leaving aside the engineering problems, you have to get to escape
>> velocity to make orbit and at altitude you run out of air to ionise.
>
> Umm, if you achieve escape velocity you , err, escape (I.e. you've
> overachieved)

Well, a mass driver up the side of Everest would give you sort of
a jump start. ;-)

Cheers!
Rich

Rich Grise

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May 19, 2005, 1:41:40 PM5/19/05

to

On Wed, 18 May 2005 22:11:57 +0000, bz wrote:

> Dirk Bruere at Neopax <di...@neopax.com> wrote in news:3f1h43F4q4r6U1
> @individual.net:
>
>> If the electrical cable was 4 cm wide made of carbon fiber, a 100km
>>> long cable would have volume Pi*.02^2*100000 = 125.7m^3. At a density
>>> of 1800 kg/m^3 for carbon fiber this would be 226,000 kg. Then twice
>>> this number in kilowatts or 452 megawatts would be needed to support
>>> the weight of the wire alone. You could have take this from the 10's of
>>> gigawatts supplied to the ioncraft or have small versions of the lifter
>>> drive all along the length of the power cable itself drawing off some
>>> portion of the power to support each small portion of the cable.
>>> The question: how much power would be lost by sending it along a 100km
>>> long cable?
>

> The wires are going to need to be able to dissipate 254 watts for each 3
> cm of length without weakening. I think the 3 cm diameter wire can take
> it.
>
> Oh, there is one other 'minor' problem. This craft will only work inside
> the atmosphere because it uses the motion of air molecules to do the
> lifting.
>
> The lift will fall off with altitude.
>
> So, you don't need to worry about lifting 100 km of wire. It can probably
> only go to a few hundred thousand feet.

Heck, with that much aluminum you might as well just build a tower. ;-)

Cheers!
Rich

bz

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May 19, 2005, 2:14:52 PM5/19/05

to

Rich Grise <rich...@example.net> wrote in
news:pan.2005.05.19....@example.net:

> Well, a mass driver up the side of Everest would give you sort of
> a jump start. ;-)

You would certainly have one heck of a pair of jumper cables. :)

Eric Chomko

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May 19, 2005, 4:07:26 PM5/19/05

to

tadchem (thomas....@dla.mil) wrote:

: Charles Jean wrote:

: <snip>

The question is, which one is Rumsfeld?

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May 19, 2005, 9:00:34 PM5/19/05

to

"Bob Monsen" <rcsu...@comcast.net> wrote in message
news:IMadncOs0cK...@comcast.com...

I don't recall a detailed explanation being in the book, but friction due to
atmospheric drag would slow the bottom of the tether pretty quickly so as to
cause problems, then once it's unstable it's manure and impellor time.

Ken

rgrego...@yahoo.com

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May 20, 2005, 2:39:01 AM5/20/05

to

Just as with electrical power transmission over long distances, you
will use very high voltage, probably in the megavolt range, that is, if
you want to lift megakilos.
In the demonstrations for small lifters, kilovolts were used to lift
only a few grams a few feet.
Since the lifter uses air for its reaction mass, you could use a
higher acceleration than that normally used for rockets to reach
orbital velocity at a lower altitude so the air is at sufficient
density. But this would reduce the lift capacity. That is, if you
accelerated at 3.6 g's, you could lift one third the mass than at 1.2
g's.
Or you could use a shallower trajectory than that used by rockets so
that most of the acceleration phase stays in the lower atmosphere. But
this would necessitate a longer and heavier cable.
Probably a combination of these would be optimal.

Bob Clark

Oren Tirosh

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May 20, 2005, 3:48:52 AM5/20/05

to

Robert Clark wrote:
> The ioncraft is a method proposed for decades for aircraft and
> spacecraft propulsion:

Lifters have only been proposed for spacecraft propulsion by the
"asymmetric capacitor" nuts who claim they work in vacuum with no
reaction mass. It may be useful for high altitude launch, though.
Lifters should be able to hover in the no-man's land above aircraft and
balloons and below stable orbit altitude where only rockets make brief
visits. A gentle ride through the thick atmosphere and separation in
near vacuum should make it much easier for the upper stage.

The wispy wire mesh structure of an ion lifter should make a good
recantenna for transmitting power by microwave without a big increase
in total weight. Transmission efficiencies in the two-digit percentage
range have been demonstrated over long distances. I believe this should
be much more practical than cables - assuming the lifter itself is up
to the task.

Lifter efficiency should probably need to be improved by almost an
order of magnitude. Evgenij Barsoukov (original source of the lifter
theory page you refer to) has some promising ideas for improving
efficiency. He has derived equasions that accurately predict ion lifter
performance and seems to be one of the few people in the lifter scene
who really know what they are talking about.

Oren

rgrego...@yahoo.com

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May 20, 2005, 4:04:44 AM5/20/05

to

Dirk Bruere at Neopax wrote:
> Robert Clark wrote:
>
> > The ioncraft is a method proposed for decades for aircraft and
> > spacecraft propulsion:
> >
> > Ioncraft.
> > http://www.markwilson.com/ioncraft/ioncraft.html
> >
> > It works by ionizing the air by electrical charge thereby creating
an
> > air flow between the electrodes, generating thrust. There are
several
> > examples of these, called "lifters", made by amateurs:
> >
> > The Lifters Experiments home page by Jean-Louis Naudin.
> > http://jnaudin.free.fr/lifters/main.htm
> >
> > The problem with them is their power supplies are much heavy than
the
> > weight they can lift. But why not leave the power supply on the
ground
> > and connect it to the craft by long power cables?

> > ...

>
> Use a uwave beam and onboard rectenna
>
> --
> Dirk

Such experiments are being conducted:

6-GHz Microwave Power-Beaming Demonstration with 6-kV Rectenna and
Ion-Breeze Thruster.
T. Cummings,* J. Janssen,* J. Karnesky,* D. Laks,* M. Santillo,* B.
Strause,* L. N. Myrabo,* A. Alden,¶ P. Bouliane,¶ and M. Zhang¶
*Department of Mechanical, Aerospace and Nuclear Engineering,
RensselaerPolytechnic Institute, Troy, New York 12180
¶Communications Research Centre, Ottawa, Ontario, Canada
"On 14 April 2003 at the Communications Research Center (CRC) in
Ottawa, Ontario, a 5.85-GHz transmitter beamed 3-kW of microwave power
to a remote rectifying antenna (i.e., rectenna) that delivered 6-kV to
a special `Ion-Breeze' Engine (IBE). Three of CRC's 26.5-cm by 31-cm
rectennas were connected in series to provide the ~6-kV output. RPI's
low-voltage IBE thrusters performed well in a "world's first"
power-beaming demonstration with rectennas and endoatmospheric
ion-propulsion engines. The successful tests were a low-tech,
proof-of-concept demonstration for the future full-sized MicroWave
Lightcraft (MWLC) and its air breathing `loiter' propulsion mode.
Additional IBE experiments investigated the feasibility of producing
flight control forces on the MWLC. The objective was to torque the
charged hull for `pitch' or `roll' maneuvers. The torquing
demonstration was entirely successful."
http://proceedings.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APCPCS000702000001000430000001

This is from the 2nd Beamed Energy Symposium:

BEAMED ENERGY PROPULSION: Second International Symposium on Beamed
Energy Propulsion.
http://proceedings.aip.org/dbt/dbt.jsp?KEY=APCPCS&Volume=702&Issue=1

A possible problem here is the power drop off with long distances, say
at the several kilometer range. You might need an exorbitant amount of
energy to be beamed in order to receive megawatts to gigawatts at the
vehicle. With the cable, a simple estimation shows you would only lose
a few percent from gigawatts of power over a hundred kilometers if the
voltage was kept in the megavolts range and you used highly conductive
aluminum.
Beamed energy is being investigated by Leik Myrabo for his
"Lightcraft." Admittedly this is using a different propulsion method
but it may be indicative of the energy requirements for beamed
propulsion:

Highways of Light,
Scientific American, February 1999,
http://www.sciam.com/article.cfm?colID=1&articleID=00058731-ED4B-1CB8-B4A8809EC588EEDF

The Myrabo laser system uses a 10 kilowatt laser to lift a 50 gram
Lightcraft about 100 ft. in the air. This is a 200 to 1 ratio of power
in watts used to the weight lifted in grams. Their goal is to lift a 1
kilo craft to orbit using a 1 megawatt laser. This is a 1000 to 1 ratio
of power used to weight lifted.
Myrabo et.al. are also investigating a microwave version of the
Lightcraft:

2. MICROWAVE LIGHTCRAFT.
http://www.geocities.com/tonylance/liteship.html#bertha

Here, 30 megawatts would be used to launch a 30 kilogram craft. This
is a 1000 to 1 ratio of power in watts used to the weight lifted in
grams. In the cable-powered lifter scenario it's about 2 to 1.
In any case we don't have laser beams or microwave tranmitters that
can put out gigawatts of power. I'm suggesting we have generators that
can put out this much power. We could begin start the process to start
lifting megakilo payloads *tomorrow*.

Bob Clark

bz

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May 20, 2005, 4:27:29 AM5/20/05

to

rgrego...@yahoo.com wrote in news:1116571140.981894.102730
@g44g2000cwa.googlegroups.com:

> Just as with electrical power transmission over long distances, you
> will use very high voltage, probably in the megavolt range, that is, if
> you want to lift megakilos.

Unforetunately, you almost certainly can't scale up the voltage
significantly.

You will get arcing if you go up on the voltage, rather than ions.

Even if you could scale up the voltage, you would have two MAJOR problems.

1) arcing between the cables, the cables to the grid, or from the discharge
points to the grid.

2) xrays radiation generation. When you have voltages over about 33 kV, you
start getting significant soft x-ray generation when electrons accelerated
by such a potential are stopped. Dental x-ray machines use 70 kV. If you go
to mega volts, you will be making very hard x-rays.

> In the demonstrations for small lifters, kilovolts were used to lift
> only a few grams a few feet.
> Since the lifter uses air for its reaction mass, you could use a
> higher acceleration than that normally used for rockets to reach
> orbital velocity at a lower altitude so the air is at sufficient
> density. But this would reduce the lift capacity. That is, if you
> accelerated at 3.6 g's, you could lift one third the mass than at 1.2
> g's.
> Or you could use a shallower trajectory than that used by rockets so
> that most of the acceleration phase stays in the lower atmosphere. But
> this would necessitate a longer and heavier cable.
> Probably a combination of these would be optimal.

That reminds me of one other problem. Weather. Humidity.
The launch site will need to be in an area with very dry climate.

High humidity, clouds, or rain, will be very bad for such a device.

Gary Williams

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May 20, 2005, 4:47:55 AM5/20/05

to

In article <IMadncOs0cK...@comcast.com>,

>It's not actually scifi. There are lots of advocates of orbital tethers.
>The one in Red Mars was constructed out of one of the moons, by
>'growing' the tether in both directions. I guess they had to shift the
>orbit of the moon first, so it was geostationary, but hey, it was scifi.
>
>Also, that means my 'centrifugal force' explanation was bogus. It would
>be, effectively, orbiting with the planet, with the center of mass in a
>geostationary orbit.
>
>In the story, when the tether was cut, something caused it to contact
>the ground, which created friction, effectively bringing the entire mass
>down over a period of a few hours or days. I can't remember many of the
>details, and somebody seems to have 'borrowed' my copy of the book.

Those interested in this might like to follow up the following links:

http://www.liftport.com/
(See the FAQ for discussions of disaster scenarios)

http://www.space.com/businesstechnology/technology/edwards_boldly_050218.html

http://liftwatch.org/tiki-view_articles.php

Gary Williams

Rich Grise

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May 20, 2005, 11:33:44 AM5/20/05

to

> I don't recall a detailed explanation being in the book, but friction due to
> atmospheric drag would slow the bottom of the tether pretty quickly so as to
> cause problems, then once it's unstable it's manure and impellor time.
>

What air friction? It's already moving at zero speed relative to the
surface of the Earth before it's cut, so "slow the bottom of the tether"
doesn't really mean anything. What's slower than zero?

I did read a story or essay, where the guy actually treated a tether
seriously, and he did some numbers, and they were mind-boggling. To do it,
he started with a BIG geostationary satellite, and started feeding
tether lines from the near and far sides simultaneously, so that they'd
balance. But at any place except that orbit, the tethers are subjected
to tidal forces - they're being pulled on. Eventually, by the time they
had 22,500 miles of Kevlar unreeled, there was so much tension on it
that it had to be like thousands of feet thick. This is one of the
problems they have with cables to deep-diving submersibles - the cable
has to be made neutrally buoyant, because otherwise it can't support
its own weight.

Once, when I was a kid, we tied a whole ball of string to a helium
balloon, figuring it would go as high as how much string we had. It
didn't go higher than maybe 100 feet, and the string just went slack.
(gradually, of course.) The weight of the string itself held the balloon
at sort of an equilibrium height.

Cheers!
Rich

Joe Strout

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May 20, 2005, 12:38:34 PM5/20/05

to

In article <pan.2005.05.20...@example.net>,
Rich Grise <rich...@example.net> wrote:

> I did read a story or essay, where the guy actually treated a tether

> seriously, and he did some numbers, and they were mind-boggling...

> Eventually, by the time they
> had 22,500 miles of Kevlar unreeled, there was so much tension on it
> that it had to be like thousands of feet thick.

You need to read some of the more recent studies. There are materials
much better than kevlar, though none quite good enough yet to make a
space elevator practical -- but progress towards that material is being
made pretty rapidly, and this is no longer an idea to be dismissed
lightly. At least one company is actively pursuing it (and is now
working with NASA to spur the development of appropriate climbers via
the Centennial Challenges program).

,------------------------------------------------------------------.
| Joseph J. Strout Check out the Mac Web Directory: |
| j...@strout.net http://www.macwebdir.com |
`------------------------------------------------------------------'

Robert Clark

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May 20, 2005, 1:04:12 PM5/20/05

to

You would locate the launcher at the gigawatt scale at very dry areas.
While transmission lines typically carry hundreds of kilovolts some do
go up to a million volts.
Using voltages in the hundreds of kilovolt range, power stations
already exist that transmit gigawatts of power over hundreds of
kilometers:

Quebec - New England Transmission.
http://www.answers.com/main/ntquery?method=4&dsid=2222&dekey=Quebec+-+New+England+Transmission&gwp=8&curtab=2222_1

Bob Clark

Puppet_Sock

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May 20, 2005, 1:12:14 PM5/20/05

to

rgrego...@yahoo.com wrote:
> Rich Grise wrote:

> > On Tue, 17 May 2005 12:53:31 -0700, Robert Clark wrote:
> >
> > > The problem with them is their power supplies are much heavy
than
> the
> > > weight they can lift. But why not leave the power supply on the
> ground and
> > > connect it to the craft by long power cables?
> >

> > Because 100 miles of copper power cable is even heavier?
> >

> > Thanks,
> > Rich

>
> Aluminum is almost always used for high voltage power lines. This is
> because of its lower weight:
>
> Aluminium's Electrical Uses.
> http://www.world-aluminium.org/applications/electrical/
>
> At 2700 kg/m^3, it's weight is only 50% more than carbon fiber. So a
4
> cm wide, 100km long aluminum cable would only weigh 340,000 kg. This
> compares to 2 million kg for the space shuttle with solid rocket
> boosters.

As Al says, getting to 100km is a no-brainer. You can use lots of
fairly simply methods to get that high. IIRC, it's not *that* much
higher than balloon records.

But the shuttle, which you want to compare to, thrusts for something
like 5 or 6 minutes to reach orbit. It goes *MUCH* farther than 100km
while still under thrust. You should be thinking more like 3000km
than 100km. IIRC, engine shutoff is someplace over Europe or so.
Multiply that 3.4E5 kg by 30 and it don't look so good any more.

In addition, the strongest cable yet manufactured is not going to
hold its own weight at 100km. (It's probably not going to do it at
10km, though I won't take any bets on that.) Do you feature a 4cm
cable holding 340,000 kg? Never mind doing it while this vehicle
is blasting away at many g's through the air.

Can you say "twang?" Knew you could. Cables have some stretch,
and then they snap. That would be pretty impressive for all
concerned. This many km long cable snaps someplace in the
middle, and both ends coil back to their connections. The
ground end snaps back pulverizing anybody silly enough to
be watching from the launch site. The sky end smacks into
the vehicle, at a relative velocity of "too many I'm sure,"
slicing it neatly into dozens of chunks. This shrapnel then
finishes up falling onto whoever happens to be downrange,
all at a velocity of several km/s. In 100 tonne amounts.

This could cause the neighbours to complain.

And even if the damn thing could work, you'd wind up with
this string of wire hanging in mid air, then falling back
with a certain amount of dispatch. The neighbours might be
more seriously pissed the higher the fool thing got. What
would, say, Span have to say if a multi-thousand-km cable
were to be dropped on them at orbital speeds? I doubt it
would resemble "Ole!"
Socks

SioL

unread,

May 20, 2005, 12:54:21 PM5/20/05

to

"Rich Grise" <rich...@example.net> wrote in message news:pan.2005.05.20...@example.net...

> I did read a story or essay, where the guy actually treated a tether
> seriously, and he did some numbers, and they were mind-boggling. To do it,
> he started with a BIG geostationary satellite, and started feeding
> tether lines from the near and far sides simultaneously, so that they'd
> balance. But at any place except that orbit, the tethers are subjected
> to tidal forces - they're being pulled on. Eventually, by the time they
> had 22,500 miles of Kevlar unreeled, there was so much tension on it
> that it had to be like thousands of feet thick. This is one of the
> problems they have with cables to deep-diving submersibles - the cable
> has to be made neutrally buoyant, because otherwise it can't support
> its own weight.

http://seattlepi.nwsource.com/business/221576_liftport26.html

I wonder if these guys are serious or perhaps just using publicity to
sell their nanotubes for other purposes.

--
Siol
------------------------------------------------
Rather than a heartless beep
Or a rude error message,
See these simple words: "File not found."

bz

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May 20, 2005, 2:02:28 PM5/20/05

to

"Robert Clark" <rgrego...@yahoo.com> wrote in

news:1116608652.3...@g44g2000cwa.googlegroups.com:

> You would locate the launcher at the gigawatt scale at very dry areas.
> While transmission lines typically carry hundreds of kilovolts some do
> go up to a million volts.
> Using voltages in the hundreds of kilovolt range, power stations
> already exist that transmit gigawatts of power over hundreds of
> kilometers:

I haven't found any 1 MV transmission lines. 450 kV is the highest I saw,
but I did find some cool pictures of arcs and sparks.

http://teslamania.delete.org/frames/longarc.htm

Also some real neat looking pictures of the results of 'quarter shrinkers'.
Which use very high pulsed magnetic fields to shrink coins.

Joe Strout

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May 20, 2005, 3:47:28 PM5/20/05

to

In article <nZoje.12222$F6.25...@news.siol.net>,
"SioL" <Sio_s...@same.net> wrote:

> http://seattlepi.nwsource.com/business/221576_liftport26.html
>
> I wonder if these guys are serious or perhaps just using publicity to
> sell their nanotubes for other purposes.

They are very serious. Any selling of the nanotubes for other purposes
is just to fund further development of the space elevator.

jmfb...@aol.com

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May 21, 2005, 6:07:52 AM5/21/05

to

In article <a9Oie.79$25.1...@news.uchicago.edu>,
mme...@cars3.uchicago.edu wrote:
>In article <1116446501.8...@f14g2000cwb.googlegroups.com>,

"tadchem" <thomas....@dla.mil> writes:
>>
>>Charles Jean wrote:
>>
>><snip>
>>
>>> "There are known knowns. These are things that we know we know.
>>> There are known unknowns. That is to say, there are some
>>> things that we know we don't know. But there are also unknown
>>> unknowns. These are things we don't know we don't know."
>>> -Secretary of Defense Donald Rumsfeld
>>
>>If Rummy really said this,
>

>He did.

I dropped my jaw to hear this from a dais located in Washington D. C.
He also did other things that were fraught with intelligence.

>
>> then he is much more widely read than I
>>would have believed. This is a variation of a quotation from Lady
>>Burton, attributed as an 'Arabian Proverb':
>>"Men are four:
>>He who knows not and knows not he knows not, he is a fool--shun him;
>>He who knows not and knows he knows not, he is simple--teach him;
>>He who knows and knows not he knows, he is asleep--wake him;
>>He who knows and knows he knows, he is wise--follow him!"
>>

>Yep. Closer to home, note that the first category above is endowed
>with what we (meaning sci.physics regulars) refer to as "second order
>ignorance", which is the characteristic of many of our cranks.
>
>Anyway, Rummy did say this and many seemingly intelligent people
>jumped on this as a "dumb statement", not realizing that it was their
>own stupidity they were thus proclaiming.

Yes, these types fixed his behaviour. Now anything that is decided
or accomplished using brains, as they should be used, will not
be documented. I drove down to Bethesda a couple of years ago
and kept looking for the toll booth where everybody had to hand
in his/her organ that contains common sense.

I got that book. I've read the first two chapters. I spent my
dreamtime last night editing my mental data base. I'm so tired.

/BAH

Subtract a hundred and four for e-mail.

mme...@cars3.uchicago.edu

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May 21, 2005, 10:35:59 PM5/21/05

to

In article <GeidncrxZrN...@rcn.net>, jmfb...@aol.com writes:
>In article <a9Oie.79$25.1...@news.uchicago.edu>,
> mme...@cars3.uchicago.edu wrote:
>>In article <1116446501.8...@f14g2000cwb.googlegroups.com>,
>"tadchem" <thomas....@dla.mil> writes:
>>>
>>>Charles Jean wrote:
>>>
>>><snip>
>>>
>>>> "There are known knowns. These are things that we know we know.
>>>> There are known unknowns. That is to say, there are some
>>>> things that we know we don't know. But there are also unknown
>>>> unknowns. These are things we don't know we don't know."
>>>> -Secretary of Defense Donald Rumsfeld
>>>
>>>If Rummy really said this,
>>
>>He did.
>
>I dropped my jaw to hear this from a dais located in Washington D. C.
>He also did other things that were fraught with intelligence.
>>

Yep.

>>> then he is much more widely read than I
>>>would have believed. This is a variation of a quotation from Lady
>>>Burton, attributed as an 'Arabian Proverb':
>>>"Men are four:
>>>He who knows not and knows not he knows not, he is a fool--shun him;
>>>He who knows not and knows he knows not, he is simple--teach him;
>>>He who knows and knows not he knows, he is asleep--wake him;
>>>He who knows and knows he knows, he is wise--follow him!"
>>>
>>Yep. Closer to home, note that the first category above is endowed
>>with what we (meaning sci.physics regulars) refer to as "second order
>>ignorance", which is the characteristic of many of our cranks.
>>
>>Anyway, Rummy did say this and many seemingly intelligent people
>>jumped on this as a "dumb statement", not realizing that it was their
>>own stupidity they were thus proclaiming.
>
>Yes, these types fixed his behaviour. Now anything that is decided
>or accomplished using brains, as they should be used, will not
>be documented.

Indeed. Would be dangerous to act otherwise.

> I drove down to Bethesda a couple of years ago
>and kept looking for the toll booth where everybody had to hand
>in his/her organ that contains common sense.

:-)))

>
>I got that book. I've read the first two chapters. I spent my
>dreamtime last night editing my mental data base. I'm so tired.
>

Well, let me know what you think, when you finish.

Mati Meron | "When you argue with a fool,
me...@cars.uchicago.edu | chances are he is doing just the same"

rgrego...@yahoo.com

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May 22, 2005, 5:26:42 AM5/22/05

to

> would, say, Spain have to say if a multi-thousand-km cable

> were to be dropped on them at orbital speeds? I doubt it
> would resemble "Ole!"
> Socks

There are a couple of ways of dealing with the horizontal distance
component of the trip. Let's say the lifter craft is moving in a
straight-line, not straight-up but at some inclination, at a constant
velocity a along this straight-line. Then the speed along this
straight-line will be v=a*t and the distance along this straight-line
will be s=(1/2)*a*t^2.
Eliminate t from these two equations to get 2*a*s=v^2. If you want v to
equal orbital velocity, about 8000m/s, then a*s = 32*10^6. If you want
s , which will be the length of the cable, to be 100,000m, then a = 320
m/s^2, about 32 g's (using g as approx. 10 m/s^2). For this
acceleration you would want the payload just to be cargo. The purpose
of this is to make launches of megakilo payloads possible at low cost
remember. Electronics can easily be hardened to withstand this
acceleration. Note also the time would only be t = v/a = 8000/320 = 25
seconds.
Or you could make the distance be 5 times longer, making the cable 5
times heavier, and the acceleration would be 6.4 g's. This is probably
within the range humans can take for a few minutes:

QUESTION:
How much speed can a body's organs take in space?
"In the case of the Space Shuttle, this acceleration is around 3 times
the force of gravity - 3g - making the crew feel three times their
normal weight, but in the early days of manned space flight, the
astronauts had a rougher ride. The Mercury capsules launched by the
Atlas booster reached a peak acceleration of 8g during ascent to orbit,
then decelerated during re-entry at loads as high as 7.8g. The Titan
rockets launched the Geminis at 7.25g, and the Saturn 5 peaked at 4g.
However, the Apollo capsules returning from the Moon re-entered the
atmosphere at over 6g."
http://quest.arc.nasa.gov/saturn/qa/new/Effects_of_speed_and_acceleration_on_the_body.txt

Astronauts probably could take 15 g's acceleration for short periods:

Armstrong.
"18 June 1959 - Centrifuge program to investigate the role of a pilot
in the launch of a multi-stage vehicle.
A centrifuge program was conducted at Johnsville, Pennsylvania, to
investigate the role of a pilot in the launch of a multi-stage vehicle.
Test subjects were required to perform boost-control tasks, while being
subjected to the proper boost-control accelerations. The highest
g-force experienced was 15, and none of the test subjects felt they
reached the limit of their control capability. As a note of interest,
one of the test subjects, Neil Armstrong, was later selected for the
Gemini program in September 1962."
http://www.astronautix.com/astros/armtrong.htm

The time at this acceleration would be 8000/150 = 53.3 seconds.
The disadvantage of using such high accelerations even for cargo is
that you could lift proportionally smaller weight. That is,
accelerating at 32 g's you could lift only 1/10th the cargo as at 3.2
g's.

So another possible solution would be to allow the total cable length
to be longer but having only a smaller portion say 100 km to be in the
air, the rest lying on the ground. You could for example have a 500km
cable length laid out beforehand on the ground. The lifter would launch
with the bottom end of its tethered cable running along the portion of
the cable on the ground. Then you could have a gentler acceleration,
about the same as for a 500km long powered flight, 6.4 g's, but the
weight of the cable that had to be supported in the air would stay at
the weight of 100km of cable.
Note that during the flight and after disconnect you probably want the
cable to be supported by smaller lifter devices along its length. This
would allow it to be returned to the launch site for reuse.
Carbon fiber can support its weight up to 300 km in height. But even
if you used aluminum the weight of the cable probably would be
supported over its length by small lifter devices anyway.
Just as with shuttle launches the lifter craft launches would be
directed to not be over populated areas during the period of powered
flight.
For the power drain, a cable 600 km long would take up to 6 times as
much power. So if the drain was 5% at 100 km, it would be 30%. You
would increase the power generated to make up for this loss.

Bob Clark

George Dishman

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May 22, 2005, 7:44:10 AM5/22/05

to

<rgrego...@yahoo.com> wrote in message
news:1116754002....@g43g2000cwa.googlegroups.com...
<snip>

> Eliminate t from these two equations to get 2*a*s=v^2. If you want v to
> equal orbital velocity, about 8000m/s, then a*s = 32*10^6. If you want
> s , which will be the length of the cable, to be 100,000m, then a = 320
> m/s^2, about 32 g's (using g as approx. 10 m/s^2). For this
> acceleration you would want the payload just to be cargo. The purpose
> of this is to make launches of megakilo payloads possible at low cost
> remember. Electronics can easily be hardened to withstand this
> acceleration. Note also the time would only be t = v/a = 8000/320 = 25
> seconds.
> Or you could make the distance be 5 times longer, making the cable 5
> times heavier, and the acceleration would be 6.4 g's. This is probably
> within the range humans can take for a few minutes:

For goodness sake Bob, try to inject some
common sense into your ideas. It isn't within
the tensile strength of the cable and we have
no engine capability that could produce the
thrust needed to accelerate the payload plus
the mass of the cable at that rate no matter
how much electrical power you give it.

Humans are irrelevant, try working out the
numbers to launch Cassini using your method.

George

jmfb...@aol.com

unread,

May 22, 2005, 6:28:30 AM5/22/05

to

In article <jeSje.115$25.2...@news.uchicago.edu>,

This irritates the hell out of me. How am I supposed to learn
stuff if those who have the knowledge can't make it available?
Politics have already sewn distribution of certain doors shut.
When will the intelligentsia finish with mundane things like
science and personal finances?

Imposing this kind of behaviour is extremely dangerous because
one of the things that these idiots jumped on was a memo
where he asked that people speculate about scenarios that
could happen and backup plans if they did occur.

>
>> I drove down to Bethesda a couple of years ago
>>and kept looking for the toll booth where everybody had to hand
>>in his/her organ that contains common sense.
>
>:-)))

I personal crank theory is that Leonardo was correct about
this sense organ and the fact that none can be found proves it.

>>
>>I got that book. I've read the first two chapters. I spent my
>>dreamtime last night editing my mental data base. I'm so tired.
>>
>Well, let me know what you think, when you finish.

I've already used it. I have a criticism but
I wish to wait until I finish because there had to be
a purpose the author organized it the way he did.

So far, most of what he has written, I've known instinctively
but could never describe in English ASCII. I'm blessing that
man's mother because he's done this work for me.

Robert Clark

unread,

May 22, 2005, 12:42:55 PM5/22/05

to

????

The point of this thread is the savings in power you would get by
using a lifter thruster method.
Look at the table near the bottom on this page:

Lifter Theory.
http://jnaudin.free.fr/html/lftheory.htm

The last line in this table labled Thrust(g)/Power(W) ratio gives the
weight that could be lifted for given power with the air density
available at ground level. It is given as 0.509, or about 2 to 1 for
power in watts required to lift a weight in grams.
This is at ground level. The thrust available becomes proportionally
less as the air density decreases so you arrange your trajectory so
that most of the powered flight occurs in the lower atmosphere. Lifter
thrust ratios at this level or better have already been demonstrated
for small test cases.
Here's a case where 185g weight of the lifter plus payload was lifted
using 200 watts of power. This is about a 1 to 1 ratio:

Saviour, the WINNER OF THE 100g of PAYLOAD CHALLENGE.
http://jlnlabs.imars.com/lifters/100gwin/index.htm

The next step is to test that this thrust ratio will hold at the
kilowatt range. Many people already own electrical generators that can
put out a few kilowatts of power. They are used for example for
generators for RV's, stand-by generators, picnic trips, etc.
This page shows such generators can be had for a few hundred dollars:

Electric Generator Store - Portable Generator, Diesel Generators ...
http://www.electricgeneratorstore.com/

For example using the 1 to 1 thruster ratio, the 3250 watt generator
advertised for $500 could lift 3.25 kilos, about 7 pounds.

Bob Clark

dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)

unread,

May 22, 2005, 12:53:00 PM5/22/05

to

Dear Robert Clark:

"Robert Clark" <rgrego...@yahoo.com> wrote in message
news:1116780175.3...@g44g2000cwa.googlegroups.com...
...

> The point of this thread is the savings in power
> you would get by using a lifter thruster method.
> Look at the table near the bottom on this page:
>
> Lifter Theory.
> http://jnaudin.free.fr/html/lftheory.htm
>
> The last line in this table labled
> Thrust(g)/Power(W) ratio gives the weight that
> could be lifted for given power with the air
> density available at ground level. It is given as
> 0.509, or about 2 to 1 for power in watts
> required to lift a weight in grams.

Lift that is not countered in any sense by "V^2" of drag through
the atmosphere. An atmosphere that becomes increasingly
conductive as it is heated, further reducing your thrust.

This is a waste of time and effort. Rocket engines are more
efficient than 50% at turning power into velocity, or even in
sustaining position.

David A. Smith

Robert Clark

unread,

May 22, 2005, 1:07:34 PM5/22/05

to

I agree the calculation does not include the effect of drag. It would
probably be analogous to the drag encountered by air-breathing methods
of space access, hypersonic craft for instance.
Rockets are efficient but you have the problem of the huge amount of
fuel mass they have to carry. At the very least lifters could provide a
low cost lower stage that could lift the craft to high altitude and to
high velocity before a final rocket stage carried the craft to orbit.
This would result in signficant levels of fuel savings.

Bob Clark

dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)

unread,

May 22, 2005, 1:49:09 PM5/22/05

to

Dear Robert Clark:

"Robert Clark" <rgrego...@yahoo.com> wrote in message

news:1116781654.2...@g47g2000cwa.googlegroups.com...

> I agree the calculation does not include the

> effect of drag. It would probably be analogous
> to the drag encountered by air-breathing
> methods of space access, hypersonic craft for
> instance.

OK.

> Rockets are efficient but you have the problem
> of the huge amount of fuel mass they have to
> carry. At the very least lifters could provide a
> low cost lower stage that could lift the craft to
> high altitude

High altitude? No, since their thrust capacity is dependent on
gas density.

> and to high velocity

High velocity? No, since their ability to thrust is dependent on
the gas being non-conductive. Heating destroys that.
Additionally, their thrusting capacity is dependent on the gas
pressure being uniform over the charged surface, which is
definately not true for something moving at more than a few tens
of miles per hour.

> before a final rocket stage carried the craft to
> orbit. This would result in signficant levels of
> fuel savings.

Only in your dreams.

David A. Smith

bz

unread,

May 22, 2005, 2:05:39 PM5/22/05

to

"Robert Clark" <rgrego...@yahoo.com> wrote in

news:1116780175.3...@g44g2000cwa.googlegroups.com:

> The next step is to test that this thrust ratio will hold at the
> kilowatt range. Many people already own electrical generators that can
> put out a few kilowatts of power. They are used for example for
> generators for RV's, stand-by generators, picnic trips, etc.
> This page shows such generators can be had for a few hundred dollars:
>
> Electric Generator Store - Portable Generator, Diesel Generators ...
> http://www.electricgeneratorstore.com/
>
> For example using the 1 to 1 thruster ratio, the 3250 watt generator
> advertised for $500 could lift 3.25 kilos, about 7 pounds.

You need 30,000 VDC. That generator puts out 110 VAC.

dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)

unread,

May 22, 2005, 5:10:11 PM5/22/05

to

Dear bz:

"bz" <bz...@ch100-5.chem.lsu.edu> wrote in message
news:Xns965E853EE9B39WQ...@130.39.198.139...

> "Robert Clark" <rgrego...@yahoo.com> wrote in
> news:1116780175.3...@g44g2000cwa.googlegroups.com:
>
>> The next step is to test that this thrust ratio will
>> hold at the kilowatt range. Many people already
>> own electrical generators that can put out a few
>> kilowatts of power. They are used for example
>> for generators for RV's, stand-by generators,
>> picnic trips, etc. This page shows such
>> generators can be had for a few hundred dollars:
>>
>> Electric Generator Store - Portable Generator,
>> Diesel Generators ...
>> http://www.electricgeneratorstore.com/
>>
>> For example using the 1 to 1 thruster ratio, the
>> 3250 watt generator advertised for $500 could
>> lift 3.25 kilos, about 7 pounds.
>
> You need 30,000 VDC. That generator puts out
> 110 VAC.

That is the least of his problems. AC to high-VDC conversion is
not trivial, but it can be done. Getting ~3000 watts is slightly
more difficult. Getting flexible, light, cabling that can
deliver it at great length? Priceless...

His problems start with his belief that "lift" equates to
"overcoming air friction due to velocity through the very medium
being used to produce lift".

And the USAF charged the skin of an aircraft for the purpose of
being stealthy. No improvement in flight characterisitics was
noted. So I suspect that if we aren't talking MHD, then we are
talking about repelling the lifting body with the Earth as one
"capacitive plate". Anything else is window dressing, mere
slight-of-hand to distract the unwary.

David A. Smith

Jim Logajan

unread,

May 22, 2005, 6:09:32 PM5/22/05

to

"tadchem" <thomas....@dla.mil> wrote:

>
> Charles Jean wrote:
>> "There are known knowns. These are things that we know we know.
>> There are known unknowns. That is to say, there are some
>> things that we know we don't know. But there are also unknown
>> unknowns. These are things we don't know we don't know."
>> -Secretary of Defense Donald Rumsfeld
>

> If Rummy really said this, then he is much more widely read than I

> would have believed. This is a variation of a quotation from Lady
> Burton, attributed as an 'Arabian Proverb':
> "Men are four:
> He who knows not and knows not he knows not, he is a fool--shun him;
> He who knows not and knows he knows not, he is simple--teach him;
> He who knows and knows not he knows, he is asleep--wake him;
> He who knows and knows he knows, he is wise--follow him!"

He who knows what just ain't so, he works in government--to hell with him!

George Dishman

unread,

May 22, 2005, 6:27:02 PM5/22/05

to

"Robert Clark" <rgrego...@yahoo.com> wrote in message
news:1116780175.3...@g44g2000cwa.googlegroups.com...
<snipped due to indentation fault in OE>

> The point of this thread is the savings in power you would
> get by using a lifter thruster method.
> Look at the table near the bottom on this page:
>
> Lifter Theory.
> http://jnaudin.free.fr/html/lftheory.htm
>
> The last line in this table labled Thrust(g)/Power(W) ratio gives the
> weight that could be lifted for given power with the air density
> available at ground level. It is given as 0.509, or about 2 to 1 for
> power in watts required to lift a weight in grams.
> This is at ground level.

This is also at zero speed. Energy is force times
distance and power is force times speed so 0.5g
rising vertically at 202 m/s would double the power
needed. You seem to be neglecting that, but at
orbital speeds it is going to be far greater than
the figures you are quoting.

This is the same problem you had with the thrust
equations, you are forgetting the basic conservation
laws for momentum and energy.

On a practical front, it is trivial to reach high
altitude, just launch from a balloon, they need no
power at all. The hard part is reaching orbital
velocity once you get up there, and lifters aren't
going to work well in a near vacuum.

the only benefit they give you is the reaction mass
of the surrounding air at low altitude but this
advantage will soon be outweighed by the inefficiency
of burning fuel to run a generator which in turn
powers the lifter as the air gets thinner.

George

bz

unread,

May 22, 2005, 7:15:05 PM5/22/05

to

"N:dlzc D:aol T:com $dlzc$" <N: dlzc1 D:cox T:n...@nospam.com> wrote in
news:Sy6ke.904$rr.807@fed1read01:

>> You need 30,000 VDC. That generator puts out
>> 110 VAC.
>
> That is the least of his problems. AC to high-VDC conversion is
> not trivial, but it can be done. Getting ~3000 watts is slightly
> more difficult. Getting flexible, light, cabling that can
> deliver it at great length? Priceless...
>
> His problems start with his belief that "lift" equates to
> "overcoming air friction due to velocity through the very medium
> being used to produce lift".
>
> And the USAF charged the skin of an aircraft for the purpose of
> being stealthy. No improvement in flight characterisitics was
> noted. So I suspect that if we aren't talking MHD, then we are
> talking about repelling the lifting body with the Earth as one
> "capacitive plate". Anything else is window dressing, mere
> slight-of-hand to distract the unwary.

The effect is apparently due to 'ion wind' induced in the air by 30kv on a
set of emission points spaced some distance above a grid of wires.

Electrons emitted by the points ionize the air. The negative ions are then
attracted to the positive grid, producing lift.

The article referenced earlier in the thread explains it better than I can.

Robert Clark

unread,

May 22, 2005, 9:37:46 PM5/22/05

to

N:dlzc D:aol T:com (dlzc) wrote:
> ...
> His problems start with his belief that "lift" equates to
> "overcoming air friction due to velocity through the very medium
> being used to produce lift".
>
> And the USAF charged the skin of an aircraft for the purpose of
> being stealthy. No improvement in flight characterisitics was
> noted. So I suspect that if we aren't talking MHD, then we are
> talking about repelling the lifting body with the Earth as one
> "capacitive plate". Anything else is window dressing, mere
> slight-of-hand to distract the unwary.
>
> David A. Smith

Leik Myrabo et.al. are investigating this type of "ionized air" drive
as a supplement to their beamed laser propulsion method:

6-GHz Microwave Power-Beaming Demonstration with 6-kV Rectenna and
Ion-Breeze Thruster.
T. Cummings,* J. Janssen,* J. Karnesky,* D. Laks,* M. Santillo,* B.
Strause,* L. N. Myrabo,* A. Alden,¶ P. Bouliane,¶ and M. Zhang¶
*Department of Mechanical, Aerospace and Nuclear Engineering,
RensselaerPolytechnic Institute, Troy, New York 12180
¶Communications Research Centre, Ottawa, Ontario, Canada
"On 14 April 2003 at the Communications Research Center (CRC) in
Ottawa, Ontario, a 5.85-GHz transmitter beamed 3-kW of microwave power
to a remote rectifying antenna (i.e., rectenna) that delivered 6-kV to
a special `Ion-Breeze' Engine (IBE). Three of CRC's 26.5-cm by 31-cm
rectennas were connected in series to provide the ~6-kV output. RPI's
low-voltage IBE thrusters performed well in a "world's first"
power-beaming demonstration with rectennas and endoatmospheric
ion-propulsion engines. The successful tests were a low-tech,
proof-of-concept demonstration for the future full-sized MicroWave
Lightcraft (MWLC) and its air breathing `loiter' propulsion mode.
Additional IBE experiments investigated the feasibility of producing
flight control forces on the MWLC. The objective was to torque the
charged hull for `pitch' or `roll' maneuvers. The torquing
demonstration was entirely successful."
http://proceedings.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APCPCS000702000001000430000001

Experimental investigation of 2-D ion mobility endoatmospheric drive
(IMED).
U. Filiba, L. N. Myrabo, and H. T. Nagamatsu (Rensselaer Polytechnic
Inst., Troy, NY)
AIAA-2001-3667
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 37th, Salt
Lake City, UT, July 8-11, 2001
http://www.aiaa.org/content.cfm?pageid=406&gTable=mtgpaper&gID=21851

The "endoatmospheric ion-propulsion" engine is clearly the same thing
as the lifter drive.

unread,

May 22, 2005, 11:13:10 PM5/22/05

to

Pat Flannery <fla...@daktel.com> wrote in news:1192h0gfm5ffrf3
@corp.supernews.com:

>
>
> bz wrote:
>
>>You need 30,000 VDC. That generator puts out 110 VAC.
>>
>>
>
> I got walloped by 20,000 VAC

Ouch. Well, high voltage AC is slightly less dangerous than 110 VAC because
it is more likely to throw you clear of the circuit.

110 AC is especially dangerous because you tend to 'freeze on'.

> (or DC...I'm not sure which, except you
> could do one hell of a Jacob's ladder set-up with it.) out of a furnace
> ignition coil that ran on 120 VAC.

Probabaly AC. Ignition coils are transformers and those produce AC. I doubt
that it was then rectified and filtered to produce DC.

> Didn't most early lifters run on flyback transformers off of computer
> monitor screens?

I don't know the details of how they produce the DC. Just saw that the
lifters needed 30,000 VDC.

> The important thing is how much total electrical energy is being used-
> not its voltage, but its wattage.

You don't generate streams of electrons and ion wind with low voltages.

Lifting will take power and high voltage.

dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)

unread,

May 22, 2005, 11:56:26 PM5/22/05

to

Dear Robert Clark:

"Robert Clark" <rgrego...@yahoo.com> wrote in message
news:1116812266.0...@z14g2000cwz.googlegroups.com...

N:dlzc D:aol T:com (dlzc) wrote:
> ...

> The "endoatmospheric ion-propulsion" engine
> is clearly the same thing as the lifter drive.

Hardly. They don't need wires to the craft.

David A. Smith

dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)

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May 23, 2005, 12:03:01 AM5/23/05

to

Dear Robert Clark:

"Robert Clark" <rgrego...@yahoo.com> wrote in message

news:1116812934....@f14g2000cwb.googlegroups.com...
George Dishman wrote:
...

> If you look at the pages describing the drive, the

> electrical power is a means to create airflow.
> The thrust is due to this airflow. I'm calculating
> the thrust as you do with the rocket equation.
> What would be dependent on the speed is the
> drag. That would be a rather complicated
> dependence on the shape of the vehicle.

Especially since the shape of the vehicle would maximize the
surface for thrust, and incidentally pull a partial vaccuum to
counteract your thrust.

> As a first guess you could give the craft the
> aerodynmic shape of a supersonic or
> hypersonic vehicle and use the same type of
> intakes on those vehicles.

If you are doing the thrusting in the engine cowl, this is MHD
propulsion. It is not a "lifter".

David A. Smith

Pat Flannery

unread,

May 23, 2005, 2:22:11 AM5/23/05

to

bz wrote:

>>>
>>>
>>I got walloped by 20,000 VAC
>>
>>
>
>Ouch. Well, high voltage AC is slightly less dangerous than 110 VAC because
>it is more likely to throw you clear of the circuit.
>
>110 AC is especially dangerous because you tend to 'freeze on'.
>
>

Oh, I froze on real good- I froze on so good that I went jumping
violently down the boulevard with the electrified rod clamped tightly in
my hand and sparks coming out of my feet on each impact with the ground-
as the connection to the rod stuck in next to the anthill was completed.
I finally got far enough away that I pulled the wire off the coil, but
my whole right arm's muscles were contracted, and it was sore for a few
hours.
That was the last time I used a bread bag over an oven mit as a means of
high voltage protection.

>
>
>> (or DC...I'm not sure which, except you
>>could do one hell of a Jacob's ladder set-up with it.) out of a furnace
>>ignition coil that ran on 120 VAC.
>>
>>
>
>Probabaly AC. Ignition coils are transformers and those produce AC. I doubt
>that it was then rectified and filtered to produce DC.
>
>

I suspect it was AC also; It was basically just a big transformer, but
boy could it generate a hot arc..it had a superheated purple/yellow
plasma flame coming off the top of it.

>You don't generate streams of electrons and ion wind with low voltages.
>
>Lifting will take power and high voltage.
>
>

You know those Ionic Breeze air cleaners? If we were to take around ten
thousand of those and weld them to a spaceship, and we were in a gaseous
nebula... did I ever tell you about my plan for a rocket engine that
generates almost no thrust, but nevertheless creates an incredible
amount of noise? ;-)

Pat

mme...@cars3.uchicago.edu

unread,

May 23, 2005, 4:14:01 AM5/23/05

to

In article <qLOdnazj6NS...@rcn.net>, jmfb...@aol.com writes:
>In article <jeSje.115$25.2...@news.uchicago.edu>,

>This irritates the hell out of me. How am I supposed to learn
>stuff if those who have the knowledge can't make it available?
>Politics have already sewn distribution of certain doors shut.
>When will the intelligentsia finish with mundane things like
>science and personal finances?

Well, our Western intelligentsia turns out to be a net liability,
rather than an asset. A cancer on society, pretty much.

>
>Imposing this kind of behaviour is extremely dangerous because
>one of the things that these idiots jumped on was a memo
>where he asked that people speculate about scenarios that
>could happen and backup plans if they did occur.

Yes, and as you say, things like this are jumped on. The only useful
aspect of this is that it enables me to mark anyboody who expresses
outrage, *be it a world class scientist or a Nobel prize winner*, as
*moron* to be ignored.

....

>>>
>>>I got that book. I've read the first two chapters. I spent my
>>>dreamtime last night editing my mental data base. I'm so tired.
>>>
>>Well, let me know what you think, when you finish.
>

>I've already used it. I have a criticism but
>I wish to wait until I finish because there had to be
>a purpose the author organized it the way he did.
>
>So far, most of what he has written, I've known instinctively
>but could never describe in English ASCII. I'm blessing that
>man's mother because he's done this work for me.
>

Well, just to avoid confusion, I'm assuming that this is still John
Ruscio's book you're talking about. If so, then yes, his mother is a
very nice woman, you would like her. And as for his wife, she's one
of my favorites.

Robert Clark

unread,

May 23, 2005, 8:25:38 AM5/23/05

to

N:dlzc D:aol T:com (dlzc) wrote:
> Dear Robert Clark:
>
> "Robert Clark" <rgrego...@yahoo.com> wrote in message
> news:1116812266.0...@z14g2000cwz.googlegroups.com...
> N:dlzc D:aol T:com (dlzc) wrote:
> > ...
> > The "endoatmospheric ion-propulsion" engine
> > is clearly the same thing as the lifter drive.
>
> Hardly. They don't need wires to the craft.
>
> David A. Smith

They beam the energy to the craft using lasers or microwaves. Same
drive just different source for the power.

Bob Clark

dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)

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May 23, 2005, 9:11:39 AM5/23/05

to

Dear Robert Clark:

"Robert Clark" <rgrego...@yahoo.com> wrote in message

news:1116851138.8...@o13g2000cwo.googlegroups.com...

> N:dlzc D:aol T:com (dlzc) wrote:
>> Dear Robert Clark:
>>
>> "Robert Clark" <rgrego...@yahoo.com> wrote in message
>> news:1116812266.0...@z14g2000cwz.googlegroups.com...
>> N:dlzc D:aol T:com (dlzc) wrote:
>> > ...
>> > The "endoatmospheric ion-propulsion" engine
>> > is clearly the same thing as the lifter drive.
>>
>> Hardly. They don't need wires to the craft.
>

> They beam the energy to the craft using lasers
> or microwaves. Same drive just different source
> for the power.

Change the thread title. An enclosed MHD drive is as much like a
lifter drive, as a turbine engine is to a house fire.

David A. Smith

rap...@netscape.net

unread,

May 23, 2005, 10:11:28 AM5/23/05

to

Has there actually been any tests at low pressures ? If the pressure
was halved, then there would be less ions, but that would mean less
current. This means lower thrust but also lower power.

Is the effect that the ion keeps hitting off uncharged particles as it
is accelerated, using them as reaction mass? This also means that when
it finally hits the other terminal, it is moving very slowly.

Robert Clark

unread,

May 23, 2005, 11:38:13 AM5/23/05

to

N:dlzc D:aol T:com (dlzc) wrote:
> Dear Robert Clark:
>
> "Robert Clark" <rgrego...@yahoo.com> wrote in message
> news:1116851138.8...@o13g2000cwo.googlegroups.com...
> > N:dlzc D:aol T:com (dlzc) wrote:
> >> Dear Robert Clark:
> >>
> >> "Robert Clark" <rgrego...@yahoo.com> wrote in message
> >> news:1116812266.0...@z14g2000cwz.googlegroups.com...
> >> N:dlzc D:aol T:com (dlzc) wrote:
> >> > ...
> >> > The "endoatmospheric ion-propulsion" engine
> >> > is clearly the same thing as the lifter drive.
> >>
> >> Hardly. They don't need wires to the craft.
> >
> > They beam the energy to the craft using lasers
> > or microwaves. Same drive just different source
> > for the power.
>
> Change the thread title. An enclosed MHD drive is as much like a
> lifter drive, as a turbine engine is to a house fire.
>
> David A. Smith

You can call it MHD if you want. I'm referring to any method of
propulsion that uses either electrical or magnetic fields to propel air
that has been ionized by electrical means or otherwise.
Lifters also can work on AC current. Then in addition to the force
produced by the asymmetric electric field you could get a force due to
the Lorentz force arising from the magnetic field.

Bob Clark

Dishman

unread,

May 23, 2005, 1:01:22 PM5/23/05

to

Groups trimmed.

> If you look at the pages describing the drive, the electrical power
is
> a means to create airflow. The thrust is due to this airflow.

Or as I said the lift comes from "the reaction
mass of the surrounding air".

> I'm
> calculating the thrust as you do with the rocket equation.

I haven't seen you calculate the thrust, you
just quoted the page. You are making the same
mistake you did last time with the pipe and
nozzle, you have read the static force that
has been claimed. You are again ignoring the
simple fact that once it starts moving you
have to supply more power for the same force.

The value in the table you quote is like
tethering a helicopter to the runway with a
spring balance in between. It will tell you
how hard the helicopter can pull if it isn't
rising. Release the tether and that force
divided by the mass will give the initial
upwards acceleration of the helicopter, but
you cannot assume the acceleration will stay
constant until the helicopter is moving
vertically at Mach 15 !

For constant force, power is proportional to
speed, and speed doesn't even appear in the
table you cited. They have only tested the
static case.

If you want to calculate thrust, work out how
long the ions will be between the plates at
different air speeds and hence how much
reaction there will be. If it doesn't fall
with speed, you have missed something.

> What would be dependent on the speed is the drag. That would be a
> rather complicated dependence on the shape of the vehicle. As a first
> guess you could give the craft the aerodynmic shape of a supersonic
or
> hypersonic vehicle and use the same type of intakes on those
vehicles.

Drag is irrelevant, if the device works by
accelerating ionised air, what happens when
it exceeds the speed of sound? Think about
the basics Bob.

George

Pat Flannery

unread,

May 23, 2005, 1:27:01 PM5/23/05

to

rap...@netscape.net wrote:

>Has there actually been any tests at low pressures ? If the pressure
>was halved, then there would be less ions, but that would mean less
>current. This means lower thrust but also lower power.
>
>

It should also cut down on the danger of arcing shorting out the system.
Has anyone stacked a few lifters one on top of the other and seen if
each layer continues to accelerate the air downwards at higher velocity,
thereby generating more thrust?

Pat

Pat Flannery

unread,

May 23, 2005, 1:36:49 PM5/23/05

to

Robert Clark wrote:

> You can call it MHD if you want. I'm referring to any method of
>propulsion that uses either electrical or magnetic fields to propel air
>that has been ionized by electrical means or otherwise.
> Lifters also can work on AC current. Then in addition to the force
>produced by the asymmetric electric field you could get a force due to
>the Lorentz force arising from the magnetic field.
>
>

If you ever see a copy, get your hands on "The Future Of Flight" by Leik
Myrabo and Dean Ing (Baen Books, 1985, ISBN 0-671-55941-9 in the
paperback edition) it's chock full of exotic propulsion ideas for
spacecraft using laser, ion, and MHD drive- most powered by beamed
energy systems.

Pat

bz

unread,

May 23, 2005, 2:03:48 PM5/23/05

to

Pat Flannery <fla...@daktel.com> wrote in

news:1192tkk...@corp.supernews.com:

>
>
> bz wrote:
>
>>>>
>>>>
>>>I got walloped by 20,000 VAC
>>>
>>>
>>
>>Ouch. Well, high voltage AC is slightly less dangerous than 110 VAC
>>because it is more likely to throw you clear of the circuit.
>>
>>110 AC is especially dangerous because you tend to 'freeze on'.
>>
>>
>
> Oh, I froze on real good- I froze on so good that I went jumping
> violently down the boulevard with the electrified rod clamped tightly in
> my hand and sparks coming out of my feet on each impact with the ground-
> as the connection to the rod stuck in next to the anthill was completed.

I don't know why I get the picture of Coyote and Roadrunner. Coyote trying
to electrocute Roadrunner (ants?).

> I finally got far enough away that I pulled the wire off the coil, but
> my whole right arm's muscles were contracted, and it was sore for a few
> hours.

Do I need to say that you were lucky? AC is especially nasty if it transits
across the chest. Tends to make the heart go into ventricular fibrillation.

Death results soon thereafter without CPR and defibrillation.

> That was the last time I used a bread bag over an oven mit as a means of
> high voltage protection.

Oven mits tend to retain moisture. Bread bags often have pin holes. And
they are not thick enough to play with 20 kv either, as I am sure you now
appreciate.

>>> (or DC...I'm not sure which, except you
>>>could do one hell of a Jacob's ladder set-up with it.) out of a furnace
>>>ignition coil that ran on 120 VAC.
>

> I suspect it was AC also; It was basically just a big transformer, but
> boy could it generate a hot arc..it had a superheated purple/yellow
> plasma flame coming off the top of it.

I take it that you also had some burns on your feet?

>>You don't generate streams of electrons and ion wind with low voltages.
>>
>>Lifting will take power and high voltage.
>>
>>
>
> You know those Ionic Breeze air cleaners? If we were to take around ten
> thousand of those and weld them to a spaceship, and we were in a gaseous
> nebula... did I ever tell you about my plan for a rocket engine that
> generates almost no thrust, but nevertheless creates an incredible
> amount of noise? ;-)

In a vacuum, when you scream, no one can hear you!

--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+n...@ch100-5.chem.lsu.edu

Robert Clark

unread,

May 23, 2005, 2:33:26 PM5/23/05

to

Dishman wrote:
> > I'm
> > calculating the thrust as you do with the rocket equation.
>
> I haven't seen you calculate the thrust, you
> just quoted the page. You are making the same
> mistake you did last time with the pipe and
> nozzle, you have read the static force that
> has been claimed. You are again ignoring the
> simple fact that once it starts moving you
> have to supply more power for the same force.
>
> The value in the table you quote is like
> tethering a helicopter to the runway with a
> spring balance in between. It will tell you
> how hard the helicopter can pull if it isn't
> rising. Release the tether and that force
> divided by the mass will give the initial
> upwards acceleration of the helicopter, but
> you cannot assume the acceleration will stay
> constant until the helicopter is moving
> vertically at Mach 15 !
>
> For constant force, power is proportional to
> speed, and speed doesn't even appear in the
> table you cited. They have only tested the
> static case.
>

The thrust and power calculations are analogous to those for a jet or
a rocket. The power and thrust produced by the engines is going to be
the same no matter the mass of the craft or its speed. If you get a
craft with a very high payload its acceleration could be close to zero,
so the speed the craft attains could be small. But the thrust produced
by the engines will be the same and the power of the engines as
measured by the mass of the reaction mass moved (air or propellant) and
the speed of that reaction mass will be the same. Likewise the thrust
and power for the lifter is calculated from how much the mass of air is
accelerated with respect to the craft.
However, there is a dependence on density of air for the size of the
thrust for the lifter. For a gas, density is dependent on pressure. And
by Bernoulli's principle pressure decreases at high velocity, so it is
possible that the thrust produced will be less on that basis. I'll
check on that.

Bob Clark

bz

unread,

May 23, 2005, 3:15:51 PM5/23/05

to

Pat Flannery <fla...@daktel.com> wrote in

news:11944j6...@corp.supernews.com:

>
>
> rap...@netscape.net wrote:
>
>>Has there actually been any tests at low pressures ? If the pressure
>>was halved, then there would be less ions, but that would mean less
>>current. This means lower thrust but also lower power.
>>
>>
>
> It should also cut down on the danger of arcing shorting out the system.

The breakdown voltage of air _decreases_ as the air pressure goes down.

Paschen's Law Vs=f(N ds) where Vs is sparking potential, ds is sparking
distance and N is gas number density.

> Has anyone stacked a few lifters one on top of the other and seen if
> each layer continues to accelerate the air downwards at higher velocity,
> thereby generating more thrust?

--

George Dishman

unread,

May 23, 2005, 4:22:49 PM5/23/05

to

"Robert Clark" <rgrego...@yahoo.com> wrote in message

news:1116873206.0...@g49g2000cwa.googlegroups.com...

Learn the basic physics Bob, the power needed
is speed times mass. After you have accelerated
an object, it has kinetic and/or potential
energy that can be recovered. Conservation of
energy means you must supply that and in your
suggestion, that has to come from the electrical
feed, there is no other source.

George

Pat Flannery

unread,

May 23, 2005, 5:43:51 PM5/23/05

to

bz wrote:

>I don't know why I get the picture of Coyote and Roadrunner. Coyote trying
>to electrocute Roadrunner (ants?).
>

I never was able to lure the grackle between the two contact plates with
the slice of bread between them- it thought it looked suspicious, and it
was right to think it looked suspicious.
Vicious they are- stupid they ain't.

>
>
>
>
>>I finally got far enough away that I pulled the wire off the coil, but
>>my whole right arm's muscles were contracted, and it was sore for a few
>>hours.
>>
>>
>
>Do I need to say that you were lucky? AC is especially nasty if it transits
>across the chest. Tends to make the heart go into ventricular fibrillation.
>

I got zapped by the thing about three times total before just deciding
to leave it alone it did have a very deleterious effect on the ants
though while it was in operation...not as deleterious effect as the
molten lead had on the same anthill a couple of years later, but
effective none the less.

>
>
>Death results soon thereafter without CPR and defibrillation.
>
>

My friend said he couldn't believe I could jump that high; I told him
that the electricity really helps your muscle response.

>
>
>>That was the last time I used a bread bag over an oven mit as a means of
>>high voltage protection.
>>
>>
>
>Oven mits tend to retain moisture. Bread bags often have pin holes. And
>they are not thick enough to play with 20 kv either, as I am sure you now
>appreciate.
>
>

I was thinking about the incident last night and realized that I was
doing this within six feet of a buried telephone cable and gas main...so
after the electricity sets off the leaking gas, the people try to call
the fire department- if they are lucky, the phones just don't work- if
they are unlucky, they get lightning in their ear.

>
>
>>>>(or DC...I'm not sure which, except you
>>>>could do one hell of a Jacob's ladder set-up with it.) out of a furnace
>>>>ignition coil that ran on 120 VAC.
>>>>
>>>>
>>I suspect it was AC also; It was basically just a big transformer, but
>>boy could it generate a hot arc..it had a superheated purple/yellow
>>plasma flame coming off the top of it.
>>
>>
>
>I take it that you also had some burns on your feet?
>
>

Actually I didn't get any burns from it; the contact seemed to have
occurred over a wide enough area that no particular area got burned as
no arc occurred at any one place; It dawned on my when I was thinking
about it the the power was going through the soil in preference to my
body as long as the rod I had grabbed onto was in contact with the
ground, it was only after I pulled it clear of the soil that my body
became the route it decided to travel by back to the other rod, and that
was via my feet. I did get a electrical burn years later off of a
discharging microwave oven capacitor though. That went in the right hand
and out the left hand with an audible "bang" noise, and left a small
burn at either end.
Oh, and while we are the subject of fooling around with
electricity...you know those glass plasma spheres that use the Tesla
coil to generate the glowing gases that you see in stores? Well, don't
wrap wire around the outside of one to see if you can generate a current
in it via induction. You can, and although you will notice only a sight
tingling as you touch the end of the wire, it will give you some nifty
and deep RF burns.
On the other hand, if you want to get rid of a wart using technology
that looks like it came straight out of a Flash Gordon comic... :-)

Pat

rap...@netscape.net

unread,

May 23, 2005, 5:51:03 PM5/23/05

to

Robert Clark wrote:
> The thrust and power calculations are analogous to those for a jet
or
> a rocket. The power and thrust produced by the engines is going to be
> the same no matter the mass of the craft or its speed. If you get a
> craft with a very high payload its acceleration could be close to
zero,
> so the speed the craft attains could be small.

I dont think that is correct.

My understanding of how it works is that a (relatively) stationary
nitrogen atom is ionised near one of the terminals. This is then
accelerated towards the other terminal. When it hits the other
terminal it is neutralised.

While the ion is in motion, the terminals are applying a force on the
ion. The ion is slowed down by collisions with the air. The slower
the ion moves, the longer the force is applied. This means that
ideally you want the ion to move as slowly as possible.

However, if the air is moving, then the interaction with the air will
never reduce the speed of the ion to below that amount.

The effective speed of the ion would probably be something like

Veff = V + Vstationary

Vstationary is the speed the ion moves at when the system is hovering
and V is the speed of the lifter.

The thrust is inversely proportional to the ion speed giving something
like

T = Tstationary * ( Vstationary) / ( V + Vstationary )

(feel free to take the above with as many grains of salt as you want :)
)

Anyway, assuming that the ion moves very quickly during hover, then
Vstationary will be alot bigger than V. This means that the thrust
will only reduce slowly as the lifter increases in speed. OTOH, if
Vstationary is low, then increasing speed will greatly reduce thrust.

Pat Flannery

unread,

May 23, 2005, 6:00:49 PM5/23/05

to

bz wrote:

>>m.

>>
>>
>
>The breakdown voltage of air _decreases_ as the air pressure goes down.
>
>Paschen's Law Vs=f(N ds) where Vs is sparking potential, ds is sparking
>distance and N is gas number density.
>
>

Okay... but other than that... :-[

Pat

George Dishman

unread,

May 23, 2005, 6:19:56 PM5/23/05

to

<rap...@netscape.net> wrote in message
news:1116885063.7...@o13g2000cwo.googlegroups.com...

>
> Robert Clark wrote:
>> The thrust and power calculations are analogous to those for a jet
> or
>> a rocket. The power and thrust produced by the engines is going to be
>> the same no matter the mass of the craft or its speed. If you get a
>> craft with a very high payload its acceleration could be close to
> zero,
>> so the speed the craft attains could be small.
>
> I dont think that is correct.
>
> My understanding of how it works is that a (relatively) stationary
> nitrogen atom is ionised near one of the terminals. This is then
> accelerated towards the other terminal. When it hits the other
> terminal it is neutralised.
>
> While the ion is in motion, the terminals are applying a force on the
> ion. The ion is slowed down by collisions with the air. The slower
> the ion moves, the longer the force is applied. This means that
> ideally you want the ion to move as slowly as possible.

Right, and it also means that the energy given to the
ion is shared with the other molecules increasing the
effective mass. See the discussion on the page Robert
quoted where they find the effective mass is much
greater than individual molecules could account for.

The benefit is that momentum is proportional to speed
while kinetic energy is propotional to the square so
a lower speed means more thrust per watt.

> However, if the air is moving, then the interaction with the air will
> never reduce the speed of the ion to below that amount.

Also, if the air is moving quickly, there is less time
to accelerate the ions. There are many reasons why the
thrust will drop off rapidly with increasing speed.

George

rap...@netscape.net

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May 23, 2005, 6:38:31 PM5/23/05

to

>From that page the drift velocity of the ion is around 2.8 km/s
(assumes 40kV and 3 cm spacing). If that is true, then the drop in
thrust at orbital velocity of around 8km/s would be ( 2.8 ) / ( 2.8+8)
= 26% of normal thrust, so maybe not fatal.

bz

unread,

May 23, 2005, 6:46:06 PM5/23/05

to

Pat Flannery <fla...@daktel.com> wrote in news:1194jks10opj219
@corp.supernews.com:

I was attempting to encourage extending the work done by amateurs with
lifters to the kilowatts of power range. However, I am informed that
using high voltages while at the same time having high wattage means
the amperage would also be high. This can potentially be lethal.
There are relatively inexpensive ways of transforming the low voltage
put out by electrical generators to the tens of thousands of volts you
need for the lifters. If you have experience working with high voltage
and amperage, then you already know what they are.
It should not be attempted unless you are already well experienced
with working on and in high power electrical supplies.

Bob Clark

Dishman

unread,

May 24, 2005, 8:14:28 AM5/24/05

to

rap...@netscape.net wrote:

> George Dishman wrote:
> >
> > Also, if the air is moving quickly, there is less time
> > to accelerate the ions. There are many reasons why the
> > thrust will drop off rapidly with increasing speed.

For ref, the page in queston is:

http://jnaudin.free.fr/html/lftheory.htm

> >From that page the drift velocity of the ion is around 2.8 km/s
> (assumes 40kV and 3 cm spacing).

I make it 280m/s.

> If that is true, then the drop in
> thrust at orbital velocity of around 8km/s would be ( 2.8 ) / (
2.8+8)
> = 26% of normal thrust, so maybe not fatal.

My value would result in a 50% reduction at 626mph
other factors being equal. However I don't think
that is the whole story.

The equation assumes the charge moves linearly from
source to collector but with an airflow the motion
will be the vector sum of the air velocity and the
drift velocity.

The method relies on the asymmetry of a small
source creating a high field which produces the
ionisation together with a large collector to
avoid a reverse flow. Thinking of the toy example
of a tip and ring, ions from the tip will be swept
through the ring when the air is moving resulting
in a build-up of charge _behind_ the device which
will reduce its efficiency more rapidly than the
static equation. This would obviously depend on
the design but at vehicle speeds above the drift
velocity the charge once past the collector can
never catch up, so there is a good chance that the
drift speed would be a top limit.

George

Dishman

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May 24, 2005, 8:20:51 AM5/24/05

to

Robert Clark wrote:
> George Dishman wrote:

> > Learn the basic physics Bob, the power needed
> > is speed times mass. After you have accelerated
> > an object, it has kinetic and/or potential
> > energy that can be recovered. Conservation of
> > energy means you must supply that and in your
> > suggestion, that has to come from the electrical
> > feed, there is no other source.
>

> How are you measuring the power of the engines? According to the
mass
> of the craft and speed of the craft?

The mass and speed of the craft give you the power
needed to supply the kinetic energy that the craft
is gaining. Dividing the power supplied to the
engines by that figure is a measure of efficiency.

> Clearly after the engines start on the space shuttle but it is still
> latched to the launch pad, the engines are generating a tremendous
> amount of thrust and power but the speed of the vehicle is zero.

Correct, you are supplying lots of power which all
goes into heating an accelerating the exhaust gas
while none goes into craft kinetic energy. You have
an efficiency of zero.

Using the mass and speed gives you a lower limit and
the engine power will always be higher because no
design has 100% efficiency. For example, after the
lifter has passed some point, the air that was there
has been accelerated downwards and probably heated a
bit through the ionisation process, both of which are
losses in the system. Drag losses are on top of that.

George