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You guys rock! :hihi:

Thanks for taking my idea and running with it.

 

To answer some questions: the "town" within the FBS must be a rigid structure, and so it follows that the whole structure should be rigid.

 

You don't want to depend on the material strength of a single ginormous balloon. The geodesic structure is the strongest mass/volume structure possible. If the elements are carbon composites, then mass goes down even more.

 

Given a rigid geodesic structure, you have much more leeway and flexibility on the material used to construct the "skin". Multi-layer super-thin films with low thermal conductivity, high transparency to visible light, and high reflectance of infrared, with super low mass now become feasible.

 

A rigid geodesic structure enable maintenance and repair that would be impossible in a balloon.

 

Mounting "black" PV solar cell arrays INSIDE the skin would increase the amount of heat released inside the skin.

 

Light intensity, especially soft UV, increases dramatically above 20,000 feet, so we should design for the highest feasible altitude. This means that residences and shops will have to be within pressurized facilities. This adds weight. :)

 

Even with the jet streams, we have a problem. How to stay IN the jet stream, or how to get back in after we leave and descend to an altitude reachable by helicopters. As much as I dislike it, some form of propulsion is necessary. Maybe a few hundred electric prop-fans mounted on the outside. Given the cross-sectional area of the FBS, you're not going to get more than 10 or 20 MPH out of it all. :) Maybe that's enough.

 

Emergency power and heat--a valid criticism. Perhaps a small nuclear reactor (say 10 megawatts) to provide power to the prop-fans. This of course releases 10 megawatts of heat inside the FBS, which may (when added to the insolation) may provide more than enough heat to float the FBS. Which means constant dumping of heat for level flight. Which means a reserve for rapid climbing when necessary.

 

Just PLEEEEEZ don't suggest the FBS be propelled by burning fuel.

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You guys rock! :)

Thanks for taking my idea and running with it.

 

Hey! Who took our Bucky ball! ;) :hihi:

 

To answer some questions: the "town" within the FBS must be a rigid structure, and so it follows that the whole structure should be rigid.

 

You don't want to depend on the material strength of a single ginormous balloon. The geodesic structure is the strongest mass/volume structure possible. If the elements are carbon composites, then mass goes down even more.

 

Absolutely. We may yet tinker with the mile-wide size, but rigidity is demanded. Here is a geodesic sphere as a tensegrity structure per Bucky himself: >> Fig. 717.01

 

Even with the jet streams, we have a problem. How to stay IN the jet stream, or how to get back in after we leave and descend to an altitude reachable by helicopters. As much as I dislike it, some form of propulsion is necessary. Maybe a few hundred electric prop-fans mounted on the outside. Given the cross-sectional area of the FBS, you're not going to get more than 10 or 20 MPH out of it all. :( Maybe that's enough.

 

Here is where my proposal fits, and is perhaps yet not understood. By having the living space & mechanics attached rigidly but gymbaled, power is applied at the axes to cause the FBS to rotate and using the Magnus effect we achieve propulsion. Changing the axis of rotation steers the FBS. :)

 

Just PLEEEEEZ don't suggest the FBS be propelled by burning fuel.

 

Roger that...except for as I said, electolyzing water (gathered from the clouds? :)) by means of electricity from photovoltaic panels and using the Hydrogen as a combustion fuel where prudent. :) :)

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...Here is where my proposal fits, and is perhaps yet not understood. By having the living space & mechanics attached rigidly but gymbaled, power is applied at the axes to cause the FBS to rotate and using the Magnus effect we achieve propulsion...
Hmmm. :confused:

 

Well, you're right, I sure don't understand the "Magnus" effect. Without spending some time studying it, I have to say I'm very skep-tickle.

;)

 

[EDIT]-- The Magnus Effect will not provide any propulsion for the FBS. :( :(

 

For ME to work, the ball must be moving through the surrounding air. The FBS has no net velocity with respect to the surrounding air. So you could spin it all you want, nothing would happen. The FBS is carried along by the surrounding air and is motionless with respect to it. NOT like the golfball, which is has high velocity THROUGH the air.

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Hmmm. :confused:

 

Well, you're right, I sure don't understand the "Magnus" effect. Without spending some time studying it, I have to say I'm very skep-tickle.

:(

 

As long as you're smiling & studying, all is right in the world. :(

 

Here's a primer from WickedPeedonita on the Magnus Effect: ;) >> Magnus effect - Wikipedia, the free encyclopedia

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For the magnus effect to work you have to have wind and rotation of the sphere must be big enough. By gymbaling the force could be only steered up or down while still being perpendicular to the wind. But it sure would be a small force.

 

The sphere would have drag coefficient of 0.5. I guess if we want to be run by wind this is good to have relatively high coefficient.

At 10 kmh the force of drag is of about 1 Mega Newtons, at 20 kmh its already 3.5MN. Wind turbines then have to be 3MW and 21MW respectively.

 

I guess thats why moving in the wind is a good idea.

 

PS: If one would hoist 3 A380s to it it would be moving at about 12kmh :confused:

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For the magnus effect to work you have to have wind and rotation of the sphere must be big enough. By gymbaling the force could be only steered up or down while still being perpendicular to the wind. But it sure would be a small force.

 

Erhmmm...no; I disagree. Spinning a floating sphere in still air will cause it to move directionally. Moreover, properly gymbaled, any vector for the axis is achievable and so any direction of travel achievable as well. :confused:

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Erhmmm...no; I disagree. Spinning a floating sphere in still air will cause it to move directionally. Moreover, properly gymbaled, any vector for the axis is achievable and so any direction of travel achievable as well. ;)

 

No, that is not the case. :confused: Both wikipedia article and the link you originally posted say that sphere has to be moving trough the fluid, or fluid flowing by it :(. If fluid has no velocity compared to the sphere, the problem has no reynolds number! And hence no wind, no magnus force.

 

To correct your first post, jet engines have better efficiency than piston ones. It says it in the same article you linked there. On page 22, there is a comparison between pistons and jets, it clearly shows that jet planes have lower energy per seat than piston ones. Thats why piston curve stops at 1970, as it seems piston engines haven't improved since.

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Here is where my proposal fits, and is perhaps yet not understood. By having the living space & mechanics attached rigidly but gymbaled, power is applied at the axes to cause the FBS to rotate and using the Magnus effect we achieve propulsion. Changing the axis of rotation steers the FBS. :confused:
There’s a major problem with this scheme.

 

The Magnus effect produces a force proportional to the square of the velocity of the airspeed of the rotating sphere or cylinder. Balloons and other unpowered lighter-than-air craft, however, move with the wind, and thus have effectively zero airspeed. So, no matter how much power is used to rotate the envelope/hull of the big airship, and how great its angular velocity, the resulting right angle force will be effectively zero.

 

When moving from between volumes of air with differing wind velocities, there is duration of time before a LTA craft matches the wind’s ground velocity, but it’s brief.

 

If you want to be able to move a LTA craft against the wind, you need either a thrusts-producing system, such as jets or propellers, a ground/water anchor, or some more exotic but still propulsive system. Due to a big LTA craft’s large frontal area, even if very aerodynamically efficient, it will have a high drag, so moving it at even a low airspeed will require a lot of power.

 

If the LTA craft can quickly, reliably and accurately change its altitude, and has good data about wind velocities at different altitudes (eg: via detailed doppler radar), it can potentially navigate effectively by selecting an air mass going the desired direction. This is how modern recreational hot air balloons navigate. Even without good wind velocity measuring systems, a good balloonist can, under suitable wind conditions, make round-trips accurately enough to land in the same field he/she takes off from.

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No, that is not the case. :confused: Both wikipedia article and the link you originally posted say that sphere has to be moving trough the fluid, or fluid flowing by it :). If fluid has no velocity compared to the sphere, the problem has no reynolds number! And hence no wind, no magnus force.

 

Roger. Bummer. :( Sorry Pyro n' Freezy. :(

 

To correct your first post, jet engines have better efficiency than piston ones. It says it in the same article you linked there. On page 22, there is a comparison between pistons and jets, it clearly shows that jet planes have lower energy per seat than piston ones. Thats why piston curve stops at 1970, as it seems piston engines haven't improved since.

 

Well, you quote energy per seat and I quoted energy per load if I recall. ;)

 

There’s a major problem with this scheme. [of using the Magnus effect for propulsion]

 

Again, roger that as above. Gave it the ol' college try. As you say earlier anyway, not likely any one's going to actually do work on any alternatives soon, and as I say, people think satisfying their immediate desires are some kind of right because they can afford it and everbody else and the world be damned. People suck & then ya croak. :( ;)

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Erhmmm...no; I disagree. Spinning a floating sphere in still air will cause it to move directionally. Moreover, properly gymbaled, any vector for the axis is achievable and so any direction of travel achievable as well. :hihi:
Roadam is correct, Turtle. Sorry. :(

 

If the FBS has zero velocity with respect to the surrounding air that carries it, then the formulas say that the Magnus Effect is also zero.

 

Besides, old friend, spinning a sphere of 5,000 Metric Tons with a diameter of one mile would take more power than you could carry.

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Roadam is correct, Turtle. Sorry. :evil:

 

If the FBS has zero velocity with respect to the surrounding air that carries it, then the formulas say that the Magnus Effect is also zero.

 

Besides, old friend, spinning a sphere of 5,000 Metric Tons with a diameter of one mile would take more power than you could carry.

 

Roger. I acknowledged that in my last post. :( No harm, no foul. :hihi:

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There is another thing to consider. At that attitude there is quite some radiation. So more shielding is needed...

All things considered, I dont think the concept would work very well in the end. The sphere wouldnt change its attitude much and you would still need some other type of transport to get onto it.

 

I think the future of air travel is in flying wings. No matter what kind of engine you use to propel yourself, its the aerodynamics that limits you to certain speeds and power requirements. Making a plane with less drag compared to what it carries it the way to go. And another thing. Flying wings have more or less flat top. So it would be easier to fir PVs onto it.

I think the specs could be generally inserted into an equation, which will wait for now I think. :)

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Nice to see someone is doing more than armchair speculating. :) Check this bad girl out!!

 

Photos: The zeppelin flies again

...

The new-model zeppelins are also much smaller--246 feet in length, compared with around 800 feet in the olden days, and carrying just two crew members and up to 13 passengers, compared with a total of 80 to 100 or so for the big ancestors.

 

For now, Airship Ventures says, it has the one and only zeppelin in the U.S., and that's one of only three in the world.

 

As you might expect, flights won't come cheap--individual tickets start at $499 per person. (The glider ride, if I remember correctly, was somewhere in the neighborhood of $80. With the zeppelin, I'd be hoping for bit of legroom to go with the view.)

 

 

Photos: The zeppelin flies again | Crave, the gadget blog - CNET

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I came across a few interesting things:

Blended Wing Body - New Concept in Passenger Aircraft Check Klingon version :hal_skeleton:

Next thing are propfan engines. As any type of aircraft you build you need an engine that would provide thrust most effectively at certain speeds. Propfan is supposed to be able to increase efficiency by 10-30%.

Green sky thinking - carbon credits and the propfan comeback?-12/06/2007-Los Angeles-Flight International

Airworthy Electric plane!

Green sky thinking - carbon credits and the propfan comeback?-12/06/2007-Los Angeles-Flight International

As I am writing this very late at night I wont comment much. But I think that Any heavier than air aircraft that would be useful cannot rely solely on solar cells.

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I think the future of air travel is in flying wings. No matter what kind of engine you use to propel yourself, its the aerodynamics that limits you to certain speeds and power requirements. Making a plane with less drag compared to what it carries it the way to go.
There’s an aerodynamic conundrum around flying wing vs. “tube and wing” and mixed “blended wing-body” designs. The total surface area (wetted area) is reduced in and minimized in blended wing-bodies and flying wings, reducing parasitic drag (drag not related to producing lift) but in most cases, the wingspan (and resulting aspect ratio) must be reduced, increasing induced drag (drag related to producing lift). The result of this tradeoff is often that blended wing-bodies and FWs often have about the same efficiency as equivalent conventional TAWs.

 

Another issue with FWs – one of which model airplane hobbyists like myself, and early full-scale designers like the legendary Jack Northropare/were acutely aware – is stability, in particular pitch (nose up/down) stability.

 

With a TAW aircraft, either of the conventional horizontal stabilizer wing in the rear or in the front (canard) configuration, static (no control input required) pitch stability is due to differences in the lift of front and rear wing at different pitches. With a single FW, however, this difference must occur in different sections of the wing, and, unless the wind is extraordinarily long, such as with a delta wing, the effective arm of the correcting force much shorter than the TAW. It’s hard to build an efficient flying wing that’s statically stable, so most of even the oldest flying wings have used some sort of active system, either mechanical or computerized.

 

Practically, however, the stability issues is, I think, a non-issue, as most large modern aircraft are currently critically dependent on computer control systems. The old-fashioned design goal of making a plane that can be flown in the event of a complete power outage is, except for the small niche of lower-quality control “sport/experimental” planes, and “brush planes” and others designed for lower-tech support environments, of little relevance.

And another thing. Flying wings have more or less flat top. So it would be easier to fir PVs onto it.
A very good point, IMHO.
But I think that Any heavier than air aircraft that would be useful cannot rely solely on solar cells.
I agree. This is almost a certainty, as for a typical solar power output, the solar power flux at Earth is at theoretical max about 680 W/m^2. A large aircraft like a 747 has a total top cross section area of about 1000 m^2, so a 100% efficient direct solar system on a clear summer day would have about 700000 W, but needs about 200 times that much to have the same performance.

 

Pure solar airplane are possible, but capable only of low speeds - though very high altitudes. MacCready’s Gossamer Penguin, Solar Challenger (4500 W prop shaft output with the highest speed, about 50 km/h) and the unmanned Helios (21000 W, highest sustained altitude of any winged aircraft of 29523.8 m) are examples.

 

In cloudy weather and at night, pure solar planes get hardly any power, so can’t sustain altitude.

 

Practically, then, electric planes must have energy storage, such as batteries of fuel cells. The electric-powered Sonex Waiex sport plane is an example.

 

I’ve been doing a bit of figuring since I stated

There don’t appear to me to be any major show-stopper barriers to, in the next few years, building a “plug-in solar” electric airliner in the 30-seat, 500 km/h, 1500 km range “regional” class (eg: the BAe Jetstream 41)
The numbers are daunting.

 

Converting the Jetstream 41 to run on conventional LiPo batteries would give it about 9 minutes flight time, vs. its usual 2.5 hours – about enough take off, run a single pattern, and land. Assuming the best batteries available by about 2012, the flight time increases to about 27 minutes. Hydrogen fuel cells give about the same result.

 

Clearly, a 30-seat battery electric airliner would need to be designed from scratch, minimizing airframe mass and maximizing battery mass. By rough scaling estimate, the total mass would need to be about 15 times that of an equivalent kerosene turboprop, or about half the mass of a 400 passenger 747.

 

These number cause me to seriously rethink the feasibility of battery or fuel cell electric airliners, and lead me to wonder what options remain. Nuclear?

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These number cause me to seriously rethink the feasibility of battery or fuel cell electric airliners, and lead me to wonder what options remain. Nuclear?

 

One option perhaps, is to look at some past designs.

 

I would suggest Bio-diesel could be a replacement for Jet-A

 

Some extracts from Dieselair -

 

The forgotten secret of the superb German diesel flying boats.

 

-Germany built many flying boats (1930s) for various uses, most of them using the Junkers Jumo 205 diesel 2-stroke opposite pistons, with powers from 600 to 880 HP.

 

-The most economical plane would be the glider if it could glide for ever, which is why the most economical planes, and therefore the ones with the longest range, are the ones with a high aspect ratio (ratio of wing length to width) giving them a lower induced drag and a most efficient gliding ratio.

 

Therefore, to obtain a long range, basically you need a high aspect ratio, and an optimal cruise speed of some 1.3 to 1.5 times stalling speed clean. And here comes the problem with gasoline engines: at 1/3rd to 1/4th their nominal power, the specific fuel consumption (fuel consumed per HP-hour) becomes lousy because combustion is no more in optimal conditions.

 

At same fractional power, the diesel is as efficient as at full power. So maintaining cruise speed may require down to 50% of the fuel flow needed with gasoline engines operating at same fractional power, meaning so much more range.

 

A cargo diesel motor glider with a very high aspect ratio cruising around 100 kts could very well again be the most effective way to ship goods by air.

 

W W W . D I E S E L A I R . C O M -- The Diesel Air Newsletter -- Home

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Lets dream high electrical permittivity! :D EEStor - Wikipedia, the free encyclopedia

 

Btw, that sonex Wainex plane could have about 100kg worth of batteries with 52kw motor. So with current LiPoly tech it could store 12kWh. From estimates that it has 42mpg mileage !! and from that to about 17kwh/100km you could probably fly this thing for about 60-70 km. With Eesto estimates that could be extended from 150 to 400 km. That is a all great, so lets dream electric. :naughty:

 

Maybe for Australian bushes where you can be stranded in the wild without electricity, that kind of a plane fitted with solar cells would be great even if you could only do jumps of around 100km.

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