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Perpetual Motion or free energy devices

Perpetual Motion or free energy devices

Perpetual Motion or free energy devices

(OP)
OK, I was browsing you tube and came across the Gravity plane.
It uses Helium for lift and compressed air for weight.
So, we start with the thing on the ground and then it expels compressed air which reduces weight and allows helium bags to expand and becomes lighter than air.
It climbs.
Then it uses compressed air to compress more air which collapses the helium bags and makes it heavier than air again.
As it dives the air flow drives turbine air compressors to recharge the compressed air banks.
When it gets too low it discharges compressed air to allow the helium bags to reflate, climbs and repeats.

It is, wait for it, environmentally friendly and uses no fuel.
OK, I'm sold, where do i get one?

http://uk.youtube.com/watch?v=0QZ1KzveIic

 

JMW
www.ViscoAnalyser.com
 

RE: Perpetual Motion or free energy devices

(OP)
Some confusion between Hunt websites:
http://www.fuellessflight.com/
where it seems to use a "special liquid" and solar power and the other website where it uses helium and compressed air and where there is a link to a sled towed in the sea which harnesses kinetic energy from the sea through a turbine to do something else that's clever....
http://www.fuellessflight.com/techno/tech.htm
and the sea glider is at:
http://www.fuellessflight.com/SEA%20GLIDER.htm

Gee, I guess you can patent pretty well anything in the USA, set up a company and find investors.

 

JMW
www.ViscoAnalyser.com
 

RE: Perpetual Motion or free energy devices

There was a perpetual motion machine on the local TV news here a few days ago. You run an electric motor from a battery that drives a generator - Humm fine - but this one drives two generators that recharge the battery providing additional energy! The inventor pointed out that the battery lasted longer than when just driving the motor by itself.

They also interviewed a local small liberal-arts college science professor who congratulated the inventor on his experiments, but the prof didn't point out that it was a pointless perpetual motion machine - I couldn't figure out if the prof was just being polite - or not?.

RE: Perpetual Motion or free energy devices

Maybe he did but they just edited it out. Experiments with promise may have been deemed more newsworthy than pointless ones.

RE: Perpetual Motion or free energy devices

A couple of real life proposals.

Self rectifying water turbine, always turns the same way even if the water flow reverses

http://www.cetusenergy.com.au/action.php

The linear motion experiment was funny, he put a rectifing turbine under a float, and the wave action drove the thing along at about 1 knot, it didn't matter which way the waves were going.

and if you really want big engineering

http://www.biopowersystems.com/biostream.php

 

Cheers

Greg Locock

SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: Perpetual Motion or free energy devices

jmw, if it uses no fuel how does it compress the air? Your original post states it "uses compressed air to compress more air which collapses the helium bags and makes it heavier than air again"...

something is inconsistent!

No more things should be presumed to exist than are absolutely necessary - William of Occam

RE: Perpetual Motion or free energy devices

I watched the film until the continual repetition of "using compressed air to compress air to create thrust that turns turbines to compress air that's used to compress more air that's...." started to make my head spin.

I guess there's no violation of the 1st law of thermodynamics in moving a mass from one place to another, but the second law will prevent it being done by moving energy back and forth between different storage methods/media.

- Steve

RE: Perpetual Motion or free energy devices

(OP)
Hamish,
The proposition is that, on the ground and tethered, the wind will spin the turbines which will compress air and charge batteries (for instrumentation etc.)

Once there is enough of it you can take off.
 
But, assuming there is no compressed air to begin with then the helium bags are fully expanded and the thing is going to be free floating somewhere or floating on the mooring lines.

My immediate concerns are about the air compression.
Compressed air has to do three things:
[il]
  • compress the helium to take away lift
  • provide ballast
  • provide propulsion aids (its not all gravity gliding)
  • [/ul]
    These are going to have to be pretty efficient turbines.

    This won't work, we are told, with to small a vehicle because of the weight of the structure. To create something that will not only support its own weight, and carry a significant cargo it has to be very large to contain enough helium.
    That requires a correspondingly large volume of air and it needs compressing.

    But, how much compression to deflate the helium, how much to run propulsors (and while the turbines flap OK in a wind, how efficient will they be using stored compressed air?)

    In a gravity glide, how fast do you need to go to and how long a glide is necessary to develop any realistic air compression? and, how fast can you go in a giant +/-neutral buoyancy vehicle?
     

    It'll probably end up that this would work fine on a low G low density planet with a deep atmosphere but will it work on earth?

    I would hope this guy Hunt has done his sums time and again and had them checked by a sceptic.

    There would appear to be a hell of a lot of things that have to add up for it all to have the faintest chance. The higher the compressed air storage pressure, the stronger the tanks and the more weight. But if you compress more, you need less volume and that means less weight...

    But, if we assume that the turbines/compressors work well in any reasonable air flow then yes, they can harvest wind energy even when sitting idle on the ground and that is what starts to make some sense, this isn't a closed system.
    Any airflow that will turn the turbines will generate electricity for instruments and thence for controls which means compressing air between the shell and the helium bags.

    But while it doesn't present as a true perpetual motion machine, what worries is that it is a great balancing act of various factors and it all depends on being able to compress enough air into a small enough volume and at a high enough pressure, fast enough to do any good.

    So we have to start either up in the air or on the ground. If on the ground and tethered, then the turbines will run in the wind. Of course, up in the air held aloft by helium buoyancy and with no compressed air, its only source of energy is air flow through the turbines and if this is a free floating object the vehicle will tend to go with the wind so the available differential could be quite low. To have any hope of compressing enough air to provide propulsion, to wing the wings, and compress the helium bags, it is going to have collect and compress air pretty quick before someone shoots it down as a hazard.

    I'd guess free floating with no compressed air reserve would be a pretty tough situation.

     

    JMW
    www.ViscoAnalyser.com
     

    RE: Perpetual Motion or free energy devices

    I looked at this a while back.  It strikes me as a bit hokey but then started to draw me in.

    As I recall when I looked at it it doesn't claim over unity, but it does claim extreme efficiency.  The sea glider is based on how they think Whales swim so far with so little apparant energy or something like that.

    I say lets build a big one, put it down as an economic stimulus package for Engineers & Dreamers.

    KENAT,

    Have you reminded yourself of FAQ731-376: Eng-Tips.com Forum Policies recently, or taken a look at posting policies: http://eng-tips.com/market.cfm?

    RE: Perpetual Motion or free energy devices

    "This won't work" enough said, leave it there ...

    why have "swing wings" ?  how fast is this supposed to go ? M1+ ?? ... good grief





     

    RE: Perpetual Motion or free energy devices

    Swing wings are cool.

    RE: Perpetual Motion or free energy devices

    Total hooey.

    The fundamental principle, though never stated, is that you're going to harvest way more energy while descending than what you need to re-ascend.

    Why don't we just build our trucks on eccentric wheels, and they'll accelerate more on the downward stroke than they decelerate on the rebound?  The difference here is that with all the talk of helium and buoyancy and compressed air compressing other air, it confuses the issues enough that the underlying silliness is not readily apparent.

    Consider this simpler proposal:  We put a flywheel in a helicopter.  We start the flywheel spinning at high speed on the ground with some outside source.  Then use that power to fly up to altitude.  Then when power runs out, we use the rotor as a wind generator during the plummet phase to bring the flywheel back up to speed.  Then up we go again.

    Some additional considerations:
    -There's no reason to have a double fuselage other than cosmetics.  Nor is there any reason to have folding wings.
    -Storing large amounts of compressed air leads to very heavy construction.
    -Filling a commercial jet fuselage with helium wouldn't begin to lift it off the ground- it takes something much lighter built to be buoyant.  Take a look at the old dirigibles, and compare the cabin to the gas-containment area.

    RE: Perpetual Motion or free energy devices

    Why have compressed air at all?

    Just have your helium buoyancy 'bags', and some compressed helium storage with a pump in-between.  Allow the buoyancy bags to 'deflate' by pumping air backing into the storage cylinders when you need to drop, & vice versa (you may not need the pumps this direction is pressure in storage is high enough.  Or you could go real retro and try just heating cooling the helium.

    Using turbines to 'catch' more energy as you rise/drop than is used to displace the air/helium is I think the part that I think is problematic wrt thermodynamic laws.

    Their write up appears to have changed now from when I came across it before though, that or my memory's shot.

    Do they really mean swing wings or that they change the angle of incidence?
     

    KENAT,

    Have you reminded yourself of FAQ731-376: Eng-Tips.com Forum Policies recently, or taken a look at posting policies: http://eng-tips.com/market.cfm?

    RE: Perpetual Motion or free energy devices

    "Filling a commercial jet fuselage with helium ..." ... good idea, for making the pax talk like donald duck for a couple of minutes (before they expire from lack of O2).

    in any case, why helium, why not a vaccuum ?

    but, in any case, "Total hooey" ... a case of BS baffling ignorance.

    RE: Perpetual Motion or free energy devices

    Quote:

    in any case, why helium, why not a vaccuum

    Because tension is much easier to withstand in light objects.  Have you ever seen anything, ever, float up into the air due to internal vacuum?

    -handleman, CSWP (The new, easy test)

    RE: Perpetual Motion or free energy devices

    A coupla blondes come to mind...
     

    RE: Perpetual Motion or free energy devices

    So, what size of evacuated Titanium alloy hollow sphere would float in the atmosphere? density=4700 kg m-3, yield stress=1500 MPa, E=140 GPa (guessing that elastic buckling might be an issue)?

    airdensity=1.22 kg m-3, airpressure=101325 Pa

    Cheers

    Greg Locock

    SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

    RE: Perpetual Motion or free energy devices

    (OP)
    According to them:

    Quote:

    Start by using advanced new strong, lightweight materials that are now available, such as carbon fiber or Kevlar bonded with epoxy resin to construct a rigid frame and outer skin.   Additionally, lightweight non-porous Mylar will be used to form the balloon type gas-bags to hold the helium gases, which can escape more porous materials.  
    But that doesn't sound like they have made a decision which means they haven't got the answers yet, or at least, answers they like.

    See also the Hunt Power Cycle which uses heat energy at low altitudes to vaporise a special liquid, the vapours drive a turbine, and at altitude, where the temperature is lower, the gas is condensed..... i.e. using external heat energy... but is there enough of it?

    So, this puts me in mind of that nodding bird that is forever sipping water from a glass tumbler....

    Of course, it is easy to take the mickey (especially after some of the proposals we have seen) but somewhere in here might lie an opportunity, provided it doesn't rely on some as yet undiscovered miracle lightweight material so all the sums will work out.  
     

    JMW
    www.ViscoAnalyser.com
     

    RE: Perpetual Motion or free energy devices

    Personally, in my lab downstairs, I am in the process of deveoloping a chewing gum that gives back more energy than it receives.  I hope to sell it to Washington to help counter Fillibusters, then to Dentists seeking to expand their practices to include complications from Tinitis.  Next, teenagers and two year-olds.  Looking for trial test participants.  Must have OSHA insurance.  poke

    Mike McCann
    MMC Engineering

    RE: Perpetual Motion or free energy devices

    So the main differences between this design and an airship (goodyear blimp etc) are that

    1) After an initial charge by using its props on the ground (not very windy there because of the boundary layer effect so could take some time)

    2) it can then use buoyancy to increase altitude

    3) After some point it uses the stored compressed energy to reduce the buoyancy and starts to free fall

    4) it recovers the energy during the falling process via the props

    It is still going to fly pretty much like an airship but instead the (vertical) flight path will be like a sawtooth. Losses in the system will mean that the altitude gained at each subsequent peak of the 'sawtooth' will be less (dont' know by how much)

    Why not KISS and just put some solar panels on an airship to drive electric motors? Plus have some exercise bikes rigged to charge the battteries on cloudy days! winky smile

    No more things should be presumed to exist than are absolutely necessary - William of Occam

    RE: Perpetual Motion or free energy devices

    Quote (Greg):


    So, what size of evacuated Titanium alloy hollow sphere would float in the atmosphere? density=4700 kg m-3, yield stress=1500 MPa, E=140 GPa (guessing that elastic buckling might be an issue)?

    airdensity=1.22 kg m-3, airpressure=101325 Pa

    Cheers

    Greg Locock

    C'mon, Greg, you've done 90% of the work...

    1m^3 of air = 1.22kg
    We just need a 1m^3 sphere whose mass is less than this.

    Radius of 1m^3 sphere is 0.62m
    Surface area of 0.62m radius sphere: 4.84m^2
    Multiply surface area by thickness to approximate material volume, multiply by density.  It was easier to punch into Excel and guess than to solve for thickness, but I got a thickness of 0.0535 as the maximum material thickness for neutral buoyancy in atmospheric air, assuming perfect internal vacuum.  

    Oh, and that's mm, not m. About 54 microns.  Somewhere around the thickness of household aluminum foil.

    And that's not counting any carbon nanotubes!  lol
     

    -handleman, CSWP (The new, easy test)

    RE: Perpetual Motion or free energy devices

    (OP)
    I'm not flying in anything with a fuselage the thickness of bacofoil. Sorry, but no.

    JMW
    www.ViscoAnalyser.com
     

    RE: Perpetual Motion or free energy devices

    I think Mike picked up on something I previously tried to point out, some of the sites don't claim over unity, just impressive endurance/efficiency.

    I'm pretty sceptical on the flying version with anything like current state of the art technology and it's confused by over unity claims but the sea glider version is interesting.

    KENAT,

    Have you reminded yourself of FAQ731-376: Eng-Tips.com Forum Policies recently, or taken a look at posting policies: http://eng-tips.com/market.cfm?

    RE: Perpetual Motion or free energy devices

    Handleman:  You don't have to guess.
    Remember Newton's Method?
    No matter; Excel does.
    Tools|Goal Seek

     

    Mike Halloran
    Pembroke Pines, FL, USA

    RE: Perpetual Motion or free energy devices

    I considered using goal seek, but guessing was still quicker (for me) since I don't use goal seek that often.  It only took about four to get as close as I needed to.   

    -handleman, CSWP (The new, easy test)

    RE: Perpetual Motion or free energy devices

    okaayyyyy... How about that elastic buckling at .62m & 54 micron?

    I don't think we're there yet.....

    Mike

    RE: Perpetual Motion or free energy devices

    q~0.365*E*t^2*r^-2

    q being the 'likely' pressure to cause elastic buckling in a thin uniform spherical shell under external pressure, according to Mr Roark, 15.2.22

    So, the kitchen foil solution fails horribly.





     

    Cheers

    Greg Locock

    SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

    RE: Perpetual Motion or free energy devices

    Note that where you have different updrafts, it is possible to keep a glider in the air a good long time, and cover some distance- but this isn't what the proposal is about.

    RE: Perpetual Motion or free energy devices

    jmw,
    "I'm not flying in anything with a fuselage the thickness of bacofoil. Sorry, but no." ... i guess you don't fly in small turbo-props (DHC-8, 0.032" thick fuselage skins; Canadair RJ, 0.06" fuselage; Bombardier GX, 0.06" fuselage) not sure about the A320 but it wouldn't be much thicker.

    but, of course, a sphere 0.052" thick couldn't support an internal vaccuum; as other posters have posited, the compression would crush the thin shell, tho' it could survive in space (pR/t = 14.7*18.2/0.054 = 5ksi; exen as bi-axial tension it'd be fine)

    RE: Perpetual Motion or free energy devices

    I think the answer is no - but, in a thin spherical shell with internal pressure is there an elastic instability mode? It seems unlikely since any small deflection is self correcting.

     

    Cheers

    Greg Locock

    SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

    RE: Perpetual Motion or free energy devices

    rb1957, I think maybe you missed the units.  0.054 is millimeters.  54 microns.  That's only 0.0021".  The thing would collapse under its own weight in gravity.

    -handleman, CSWP (The new, easy test)

    RE: Perpetual Motion or free energy devices

    The nearest I've seen to a perpetual motion machine is that Global Warming thread...if you could harness the hot air rising there and put it to work, there'd be a tremendous source of free energy!

    RE: Perpetual Motion or free energy devices

    yeah, handleman, i mistook "microns" for thousandths of an inch (fairly usual in US/NA) instead of millionths of a meter

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