Enhanced Lifter?! / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Enhanced Lifter?!

Move Thread

LAN_403

Conundrum

Mon Aug 08 2011, 04:52PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Hi all.

I heard some rumblings on the Net about some very interesting research.

It seems that recently the same guys responsible for the lightcraft aka the laser
plasma propulsion might have worked on another one.

Essentially the plan is that >1 GHz radio waves behave very much like a laser beam,
as far as their dispersion pattern.
So all the energy is in a 10 foot wide lobe, at say 10K feet.

It appears that in order to harness this effect they are using metamaterials, so that
the energy in the beam gets converted from incident radio energy into kinetic
energy much like a solar sail which directly lifts the craft with around 5% efficiency.

Sounds too good to be true so it probably is...

Has anyone else heard of this? If true then its a very interesting advance.
Imagine a relatively simple craft that could be lifted all the way to orbit using a ground
station and aircraft mounted radar units at various altitudes to "top it up" enough using an
in-phase signal.

Sort of like using a space elevator but without the physical elevator being needed.
Also the lack of a laser would make it far safer than a lightcraft.

Feel free to laugh at or delete this thread if you wish...

-A

Forty

Mon Aug 08 2011, 06:33PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

a focused radio "laser" may be a good way to power an electrical system from far away, which you could use to power propellers for lift. but i really doubt the energy from reflected radio waves would be enough to propel an object alone while in an atmosphere. I believe solar sails get most of their propulsion from the solar wind of particles sent out by the sun, not as much from the photons.

If this research is credible, then it may provide advances in wireless energy transfer, but i don't think it could ever lift an object from earth's surface up into space.

using additional aircraft to help boost it up would be impractical because you could just take a high altitude plane and launch the small payload into orbit from it with a rocket.

Conundrum

Mon Aug 08 2011, 06:57PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Ionocraft powered by radio waves might work..

With the new graphene based conductors it should be possible to make ground foils which weigh 1/50th of what even emergency space blanket foil weighs.

Someone should do a comparative test with a graphene ground plane and a conventional foil, under the same experimental conditions.

-A

klugesmith

Mon Aug 08 2011, 07:36PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

Conundrum wrote ...
Essentially the plan is that >1 GHz radio waves behave very much like a laser beam,
as far as their dispersion pattern. So all the energy is in a 10 foot wide lobe, at say 10K feet.

Do they circumvent the laws of diffraction?
Laser diodes (without collimating lens) necessarily produce a relatively wide-angle beam, because the source size is just a few wavelengths.
For 1 milliradian beam divergence, a transmitting antenna would need an effective aperture size on the order of 1000 wavelengths (300 meters for 1 GHz). That doesn't mean it couldn't be focused down to 10' width at 10k', like the neck of an hourglass -- think ellipsoidal reflector.

Patrick

Mon Aug 08 2011, 07:47PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Klugesmith wrote ...

Dam Klugesmith has beaten me to the point of radiating geometry! I concur with K's points though, the shape of the beam would be a difficult issue to resolve in a practical way.

Forty

Mon Aug 08 2011, 08:28PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

but if your graphene space kite weighs next to nothing, don't you think the atmosphere would pose a problem with oh say... wind. lol. if you were already in space with it, then yea it'd probably work fine, albeit probably less so than solar wind sailing or laser ablation propulsion.

Mattski

Tue Aug 09 2011, 04:06AM

Registered Member #1792 Joined: Fri Oct 31 2008, 08:12PM
Location: University of California
Posts: 527

wrote ...
I heard some rumblings on the Net about some very interesting research.

Rumblings eh, any links?

I also doubt a "radio sail" would work in atmosphere, it needs to have a reasonable mechanical strength to maintain its shape even in still air while moving which means it can't be some fancy super-light material (well it can be made of something super-light but it can't be ultra-thin like solar sails are). Then to get enough force to lift it the power density of the radio waves would have to be quite large, I suspect to the point of melting the sail unless the sail is also a superconductor... not to mention that level is RF power is not especially safe. But I haven't run any numbers, maybe it could be made to work in air.

In space I'm sure it could be made to work, the question as always is whether it's worth the cost and that will take much more thought and rigor than the few minutes to took to write this response ;)

It's worth noting that in the 60's Raytheon built a 6 foot diameter radio powered helicopter which stayed aloft from several kilowatts beamed up from a dish and received by a rectenna. Though if you want to just get to altitudes a helicopter can reach then standard fossil fuel engines are still the cheapest solution.

Conundrum

Fri Nov 11 2011, 10:29AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

These days you can use lightweight nanotech LiPo cells which can store a lot of energy for a small mass at the cost of cycle life (100 charges versus 1000 is the quote)
Also means that instead of a continuous beam you send high power pulses once every ten minutes to achieve a slow ascent over several hours.

Think "translinear vector principle" here.
There would be problems with beam loss with distance but you simple compensate by using more than one beam from different locations or just increase the pulsed power.

Shame we don't have a nuclear isomer, that would make life a LOT easier as the "power source" would be a small X-ray tube or cyclotron tuned to emit the appropriate energy band.
Then use water vapour as reaction mass, simplez.
Seems that Hf178m2 *might* be such an isomer but the trigger energy if it exists at all is in the >500KeV range to get a statistically significant effect.
So you'd need to irradiate it with around 50 roentgens per second at the critical energy to make it boil a cup of coffee.

Now if you had the LED equivalent of an X-ray emitter (XRED?) then this might work.
Assuming efficiency 1 order of magnitude less than the most efficient EUV LED (around 2%) then you'd be better off using the batteries and a heater to boil water

Quote from Wikpedia on Induced Gamma Emission.

"Induced gamma emission is an example of interdisciplinary research bordering on both nuclear physics and quantum electronics. Viewed as a nuclear reaction it would belong to a class in which only photons were involved in creating and destroying states of nuclear excitation. It is a class usually overlooked in traditional discussions. In 1939 Pontecorvo and Lazard[2] reported the first example of this type of reaction. Indium was the target and in modern terminology describing nuclear reactions it would be written 115In(Î³,Î³')115mIn. The product nuclide carries an "m" to denote that it has a long enough half life (4.5 hr in this case) to qualify as being a nuclear isomer. That is what made the experiment possible in 1939 because the researchers had hours to remove the products from the irradiating environment and then to study them in a more appropriate location."

Hmm, 4.5 hours isn't too bad if the trigger energy is very low.
Ought to be long enough to get craft into orbit on a slow ascent and the waste product is relatively safe after about two weeks.

-A

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob