Passenger Drones (Concept of Mine)

[RainDreamer]

I imagine if instead of using props to lift and hover, which require constant motion and thus energy cost, we can use balloon to provide supplement lift. It would look more like an airship though, and would need space for takeoff and landing.

[Red Iron Crown]

9 minutes ago, RainDreamer said:

I imagine if instead of using props to lift and hover, which require constant motion and thus energy cost, we can use balloon to provide supplement lift. It would look more like an airship though, and would need space for takeoff and landing.

And would likely be slower than a regular car and way, way more susceptible to weather. Not to mention requiring helium (expensive) or hydrogen (handling/storage concerns).

[ZooNamedGames]

1 hour ago, Red Iron Crown said:

And would likely be slower than a regular car and way, way more susceptible to weather. Not to mention requiring helium (expensive) or hydrogen (handling/storage concerns).

Hydrogen is in the same catagory of dangerous as Methene or any other combustible gas. We've set decent safety standards for them. 

[Red Iron Crown]

2 minutes ago, ZooNamedGames said:

Hydrogen is in the same catagory of dangerous as Methene or any other combustible gas. We've set decent safety standards for them. 

We have. It's still incredibly difficult to store, and a difficult sell to the public because Hindenburg.

[ZooNamedGames]

Just now, Red Iron Crown said:

We have. It's still incredibly difficult to store, and a difficult sell to the public because Hindenburg.

We simply need to make electrolysis machines common in households to separate the hydrogen from the oxygen in water. Then provide suitable tanks. 

The tanks by themselves should be simple. Most of America has giant concrete slabs far larger than a tank they'd need and it seems no problem.

As to Hindenburg, it was a disaster, yes but we need to move on. It's been almost 100 years since the tragedy. The Titanic sunk, but the touring cruiser business did not die; it grew and improved. We've made serious jumps in science since then.

[shynung]

23 minutes ago, ZooNamedGames said:

The tanks by themselves should be simple. Most of America has giant concrete slabs far larger than a tank they'd need and it seems no problem.

Hydrogen is a PITA to store. It leaks out, molecule by molecule, through almost any tank material you can think of, no matter how tight the plumbing is fastened. It burns with an invisible flame, so one never knows they are walking into a hydrogen fire until they feel the heat. It also has utterly terrible density, requiring inordinately large tanks to store any usable amounts of them (Remember the Space Shuttle External Tank? 80% of that by volume is hydrogen, but it only makes up ~16% of the propellant mass, the rest was oxygen).

So no, the tanks wouldn't be simple.

[Robotengineer]

49 minutes ago, ZooNamedGames said:

We simply need to make electrolysis machines common in households to separate the hydrogen from the oxygen in water. Then provide suitable tanks. 

The tanks by themselves should be simple. Most of America has giant concrete slabs far larger than a tank they'd need and it seems no problem.

As to Hindenburg, it was a disaster, yes but we need to move on. It's been almost 100 years since the tragedy. The Titanic sunk, but the touring cruiser business did not die; it grew and improved. We've made serious jumps in science since then.

I defer to shynung's response on the hydrogen tanks. 

On the electrolysis machines, it would only be available in places where water is plentiful (not most of the southwest/western seaboard), and would require more electricity. 

The reason we don't have hydrogen blimps is 1) the Hindenburg disaster and 2) the creation of the passenger jet made it obsolete. 

As to the general idea of passenger drones, I think the idea could be useful for rural areas where roads and other transportation methods either take too long or are nonexistent. Use in urban/suburban areas would have to be limited to fewer people given the tighter airspace restrictions, probably acting similar to personal helicopters do now. Just IMO, I haven't read the whole thread yet so don't know how much of this is duplicitous. 

[James Kerman]

I know it's loud, inefficient, unpractical and ungainly...I still want one

[shynung]

@James Kerman Here's the next best thing:

It's basically a Glasair Sportsman light aircraft fitted with road wheels, and a second engine mounted in a pod underneath the cockpit to drive the wheels. The wings can fold rearwards for road travel.

 

Edited August 1, 2016 by shynung

[Snark]

12 hours ago, Red Iron Crown said:

And would likely be slower than a regular car and way, way more susceptible to weather. Not to mention requiring helium (expensive) or hydrogen (handling/storage concerns).

Not to mention that helium's not only expensive, but in finite supply.  There's been a helium shortage for quite some time, and if demand suddenly shot upwards, there's no easy way to suddenly increase production.  It's like quinoa:  great (if a bit pricey) for small-scale usage, but massive demand would only drive the price up without greatly increasing supply.  If we tried to move to an "everyone use lots of helium" economy, pretty quickly helium would become so excruciatingly expensive that the market would auto-correct and the initiative would drop dead in its tracks.

11 hours ago, ZooNamedGames said:

Hydrogen is in the same catagory of dangerous as Methene or any other combustible gas. We've set decent safety standards for them.

We have?  Citation please?

Bear in mind that what we're talking about, in the context of the post you just made, is not "store hydrogen in compressed, heavily armored tanks", but rather "store it in huge billowy balloons to fill up an airship with."

Can you give modern-day examples of any dangerously explosive gas that is stored, unpressurized, in giant filmy lighter-than-air containers of any sort, such that it's considered "safe"?

A hydrogen balloon is incredibly dangerous.  You have an incredibly explosion-prone gas, one that is very quick to leak through just about any material, that you're proposing to use in stupendous quantities in giant, super-light, super-thin containers, swimming through an ocean of oxidizer.  I contend that there's no way to make such a thing safe.  Do you have a concrete suggestion for doing so?  Or, for that matter:  there are lots of airships in use today, and as far as I know, they universally use expensive helium as their buoyant gas.  If there were a way to use far-cheaper and infinitely-available hydrogen instead, in a way that's safe... who's using it?

11 hours ago, ZooNamedGames said:

We simply need to make electrolysis machines common in households to separate the hydrogen from the oxygen in water. Then provide suitable tanks. 

The tanks by themselves should be simple. Most of America has giant concrete slabs far larger than a tank they'd need and it seems no problem.

What "tanks"?  We're talking about airships, here.  The hydrogen can't be in "tanks", it needs to be filling a buoyant envelope.

Unless you're talking about using on-board tanks as an energy storage mechanism for powering an aircraft, which has already been mentioned earlier in this thread:  the energy density is terrible, and the necessary pressurization containers would be too heavy.  There's a reason why there aren't any hydrogen-powered aircraft.

11 hours ago, ZooNamedGames said:

As to Hindenburg, it was a disaster, yes but we need to move on. It's been almost 100 years since the tragedy. The Titanic sunk, but the touring cruiser business did not die; it grew and improved. We've made serious jumps in science since then.

Except that there's a difference:  Hydrogen filled airships are inherently incredibly dangerous.  They are massive flying bombs.  The Titanic had a horrible tragic accident, yes (and, incidentally, killed ~50 times as many people as the Hindenburg did)... but it didn't kill the ship industry because there's nothing inherently dangerous about ships.

We've made big jumps in science in the last hundred years, yes, but the laws of chemistry and physics haven't changed.  Bulk hydrogen in flimsy buoyancy envelopes is incredibly dangerous, and there's no way to stop that.  I can name lots of technical and policy innovations that have happened since 1912 that would mitigate against another Titanic happening (satellite photos, global communications, radar, sonar, electronic monitoring systems, laws requiring adequate lifeboat capacity, etc.).  Can you name any advance that's happened since 1937 that would make giant airborne bags of hydrogen safe to use?  Not just "safer than the Hindenburg", but passenger-airlines safe?

I could imagine that we could do a better, safer job than 1937 technology.  Given the right economic incentives, I could even imagine some modern scenarios where hydrogen-buoyant airships might be a viable answer (e.g. heavy cargo lifters in remote places without roads, flying over unpopulated areas, that are either unmanned or else have small crews who are willing to sign waivers and are paid enough to be willing to take the risk).  But that's a far cry from something that you could use in a common passenger scenario.

In any case... you can't have "blimps for everyone for everyday use", even if hydrogen could somehow be made safe to use.  They're far too bulky.  They're utterly at the mercy of the weather.  They're incredibly loud.

[wumpus]

19 hours ago, adsii1970 said:

As someone that has done research into mass transportation (because of classes for the Ph.D.), there's a few unspoken "rules" - for lack of a better term, when it comes to the American mindset on transportation. Americans want dependable, easy-to-use, moderate cost, low maintenance, and stylish when it comes to personal transportation. When it comes to public transportation, Americans want cheap, easy-to-use, and convenient. With that said...

I am not sure if the American public is ready for a drone car for several reasons -

• It is not cost effective when it comes to maintenance and fuel, at least with the current concepts we've seen presented here.
• It is not easy to use - consider balanced cargoes, counterweights needed (or auto-adjusting thrust to compensate for unbalanced payloads - this adds complexity and expense to the project)
• Americans would demand creature comforts which adds weight (think of how much weight that cars have added just for air conditioning!)
• It would have to be able to replace the car completely - as in able to go from front door to the office and back!

And this is just a quick list.  There's other things that will have to be addressed and considered as well.

 

Cost effective:  This is mostly a matter of time and economic growth.  Of course, I think power usage is flattening out in some developed western countries (mostly Europe), so unless there is sufficiently abundant energy, it won't happen.

Easy to use: Freewings don't have this issue, and for multiple rotors (no, just no) it would be a reasonably simple control logic issue.  I have to wonder if there will be real attempts at "flying cars" after people accept autonomous cars.  The biggest issue with having the general public flying is watching them fail at 2d real-time navigation.

Creature comforts:  I've often wondered why Cessnas  don't look more like sailplanes: greatly reducing the frontal area should greatly allow for higher speeds. [N.B. I've heard of flutter and understand that it often limits max speed (literally Vne), but have no idea what causes it and how to avoid it], yet aircraft with the passenger beside the pilot greatly outsells having the passenger directly behind the pilot.  Ignore this line at your peril.

Complete replacement:  The exceptions tend to prove the rule: one option would be for the plane to carry the "car" (segway?) if you can't quite land on top of the landing area.  Note that it might be possible to convince enough people for a short production run (like the Lotus-based Tesla Roadster) for people willing to buy a car for each end of a flight, but that will never be mass market.  Unless people are keeping a gas (probably their "old car") around and buying Nissan Leafs for running about (I suspect this was true for the pre-supercharger Telsa Roadster), I wouldn't even expect a car to remain for short trips.

Edited August 1, 2016 by wumpus
stupid strikethrough bug

[ZooNamedGames]

14 minutes ago, Snark said:

Not to mention that helium's not only expensive, but in finite supply.  There's been a helium shortage for quite some time, and if demand suddenly shot upwards, there's no easy way to suddenly increase production.  It's like quinoa:  great (if a bit pricey) for small-scale usage, but massive demand would only drive the price up without greatly increasing supply.  If we tried to move to an "everyone use lots of helium" economy, pretty quickly helium would become so excruciatingly expensive that the market would auto-correct and the initiative would drop dead in its tracks.

We have?  Citation please?

Bear in mind that what we're talking about, in the context of the post you just made, is not "store hydrogen in compressed, heavily armored tanks", but rather "store it in huge billowy balloons to fill up an airship with."

Can you give modern-day examples of any dangerously explosive gas that is stored, unpressurized, in giant filmy lighter-than-air containers of any sort, such that it's considered "safe"?

A hydrogen balloon is incredibly dangerous.  You have an incredibly explosion-prone gas, one that is very quick to leak through just about any material, that you're proposing to use in stupendous quantities in giant, super-light, super-thin containers, swimming through an ocean of oxidizer.  I contend that there's no way to make such a thing safe.  Do you have a concrete suggestion for doing so?  Or, for that matter:  there are lots of airships in use today, and as far as I know, they universally use expensive helium as their buoyant gas.  If there were a way to use far-cheaper and infinitely-available hydrogen instead, in a way that's safe... who's using it?

What "tanks"?  We're talking about airships, here.  The hydrogen can't be in "tanks", it needs to be filling a buoyant envelope.

Unless you're talking about using on-board tanks as an energy storage mechanism for powering an aircraft, which has already been mentioned earlier in this thread:  the energy density is terrible, and the necessary pressurization containers would be too heavy.  There's a reason why there aren't any hydrogen-powered aircraft.

Except that there's a difference:  Hydrogen filled airships are inherently incredibly dangerous.  They are massive flying bombs.  The Titanic had a horrible tragic accident, yes (and, incidentally, killed ~50 times as many people as the Hindenburg did)... but it didn't kill the ship industry because there's nothing inherently dangerous about ships.

We've made big jumps in science in the last hundred years, yes, but the laws of chemistry and physics haven't changed.  Bulk hydrogen in flimsy buoyancy envelopes is incredibly dangerous, and there's no way to stop that.  I can name lots of technical and policy innovations that have happened since 1912 that would mitigate against another Titanic happening (satellite photos, global communications, radar, sonar, electronic monitoring systems, laws requiring adequate lifeboat capacity, etc.).  Can you name any advance that's happened since 1937 that would make giant airborne bags of hydrogen safe to use?  Not just "safer than the Hindenburg", but passenger-airlines safe?

I could imagine that we could do a better, safer job than 1937 technology.  Given the right economic incentives, I could even imagine some modern scenarios where hydrogen-buoyant airships might be a viable answer (e.g. heavy cargo lifters in remote places without roads, flying over unpopulated areas, that are either unmanned or else have small crews who are willing to sign waivers and are paid enough to be willing to take the risk).  But that's a far cry from something that you could use in a common passenger scenario.

In any case... you can't have "blimps for everyone for everyday use", even if hydrogen could somehow be made safe to use.  They're far too bulky.  They're utterly at the mercy of the weather.  They're incredibly loud.

I was referring to household tanks to be used in combustion not balloons. I can make a hot air balloon today and call it done. 

"Tanks" refer to the container before being shifted into a vehicle such as a car.

As to safety standards for Methene containment and storage... Do I really need to tell you? I thought we had decent storage of it in certified tanks like the ones shown above.

And if I was confused as to my statement; it's because I've tried to jump ship off this topic but someone always quotes me and drags me back to explain myself.

[shynung]

23 minutes ago, Snark said:

Except that there's a difference:  Hydrogen filled airships are inherently incredibly dangerous.  They are massive flying bombs.

I disagree. Here's my previous take on it:

Quote

Yes, hydrogen airships are flammable. Yes, they can be dangerous if built poorly. Yes, Hindenburg will happen again if precautions aren't taken during flight.

But hydrogen airships aren't exactly large floating fuel-air-bombs. They're quite durable, for a few reasons:

-Inside the airship's envelope, the gas is kept at barely above local atmospheric pressure. When the vessel climbs, the envelope inflate to compensate. This means if there are any leaks (say, some bloke aimed a machine gun at it), leaks would happen slowly and, due to the enormous volume of the envelope (and their pressurized hydrogen stores) , pressure would go down slowly as well. If the leaking gas caught fire, given a fireproof envelope, it would not bring down the ship, since the slight overpressure ensures that outside air do not get into the envelope. It's still an emergency, since the vessel is on fire, but most likely survivable.

-The gas inside the balloon is pure hydrogen. This, on it's own, will not burn; it has to be mixed in with outside air to be able to burn. Even if an explosive charge is set off inside the envelope, all it would do is send a pressure wave spike inside the envelope, popping off safety valves and/or overpressure patches (sections of the envelope designed to fail if pressure exceeds a safe limit). Once on the ground, these are easily repaired and patched over, and the airship is good to go.

-The airship envelope is a soft material that won't set off on-contact explosives. Explosive ammunition like this won't be set off on impact, simply punching holes in the fabric smoothly and go unmolested all the way to the outer side, unless it hits something solid inside. Even if it does hit something, pure hydrogen gas do not burn.

To bring down an airship quickly, one would need a warhead that can cut through large swaths of fabric, like this:

This would immediately drop the internal pressure of the airship, while also letting a lot of hydrogen mix with the air. At this state, the hydrogen airship can be blown up with ease.

That said, I do agree that airships are obsolete for most purposes. They are good for long-term loitering, though.

Edited August 1, 2016 by shynung

[RainDreamer]

Well, hurling a hunk of material through air is always more difficult than trying to rolling it on the ground. I wonder at what point the need to travel becomes great enough we need to go vertical as well.

[Green Baron]

11 hours ago, ZooNamedGames said:

We simply need to make electrolysis machines common in households to separate the hydrogen from the oxygen in water. Then provide suitable tanks. 

 

The dangers of Hydrogen have been addressed. I would have guessed that obtaining hydrogen through electrolysis, liquifying it for storage (-253°C) and then storing it in the "household" could exceeds the capabilities, in terms of money, technology and security, of most households in the world, or not ?

Also i would think that a compressed hydrogen gas can't be confined for long, cause cute little atoms love to live in freedom. Can almost hear the distant "booms" in other people's gardens :-)

Is hydrogen technology ready for "personal use" ?

 

[Snark]

15 minutes ago, ZooNamedGames said:

I was referring to household tanks to be used in combustion not balloons. I can make a hot air balloon today and call it done. 

"Tanks" refer to the container before being shifted into a vehicle such as a car.

Ah, okay.  You were responding to this post of Red Iron Crown's, in which the context was airship buoyancy, not tanks for energy storage.  He was talking about the safety of big buoyant bags of hydrogen, not the safety of small armored pressure tanks.

Since you're talking about tank storage for hydrogen:  Yes, it exists.  But it's not a viable option for powered aircraft.  A tank that's strong enough to be safe is too heavy; and in any case, hydrogen has crappy energy density compared with gasoline or jet fuel.

That's not to say it's physically impossible to build a hydrogen-powered aircraft, simply that it's not economically viable because other options are safer, cheaper, and more effective.  There's a reason why there aren't any hydrogen-powered aircraft.

[ZooNamedGames]

6 minutes ago, Green Baron said:

The dangers of Hydrogen have been addressed. I would have guessed that obtaining hydrogen through electrolysis, liquifying it for storage (-253°C) and then storing it in the "household" could exceeds the capabilities, in terms of money, technology and security, of most households in the world, or not ?

Also i would think that a compressed hydrogen gas can't be confined for long, cause cute little atoms love to live in freedom. Can almost hear the distant "booms" in other people's gardens :-)

Is hydrogen technology ready for "personal use" ?

 

It's a growing technology; besides I'm referring to the gas, not liquid.

[Snark]

5 minutes ago, Green Baron said:

The dangers of Hydrogen have been addressed. I would have guessed that obtaining hydrogen through electrolysis, liquifying it for storage (-253°C) and then storing it in the "household" could exceeds the capabilities, in terms of money, technology and security, of most households in the world, or not ?

If you're talking about a fixed ground installation-- where weight and portability isn't a concern-- then I see no reason why small-scale hydrogen storage on-site would have to be a problem.  Just make a big pressure tank.  Bury it for safety, if need be.  The question is, why would you do this?  Where's the economic incentive?  Bear in mind that electrolyzing and then burning hydrogen is going to be losing electricity to inefficiency; how is this superior to, for example, just getting big banks of lithium-ion batteries and storing the electricity chemically, to be released at need?

(Of course, those batteries are expensive, but the price has been plummeting for years and looks ready to continue to do so-- it's a question of economies of scale, and we don't appear to have bottomed out yet.)

[shynung]

5 minutes ago, ZooNamedGames said:

It's a growing technology; besides I'm referring to the gas, not liquid.

Even as a gas, hydrogen still gets through the molecules of the tank. If the vehicle carrying the tank is stored in a closed, unventilated garage for a long period of time, a dangerous gas concentration may appear. When that happens, a smallish spark is enough to set off the whole shebang.

Also, even if we do have tanks that are light enough, yet strong enough to contain pressurized hydrogen gas, there is no getting around the low energy density of hydrogen. Usable range would be terrible compared to hydrocarbon vehicles.

Let's just face it, hydrogen as a fuel isn't much of a good idea for everyday use. Sure, rockets get better specific impulse from using it as propellant, but we don't exactly commute using rockets nowadays.

[ZooNamedGames]

16 minutes ago, shynung said:

Even as a gas, hydrogen still gets through the molecules of the tank. If the vehicle carrying the tank is stored in a closed, unventilated garage for a long period of time, a dangerous gas concentration may appear. When that happens, a smallish spark is enough to set off the whole shebang.

Also, even if we do have tanks that are light enough, yet strong enough to contain pressurized hydrogen gas, there is no getting around the low energy density of hydrogen. Usable range would be terrible compared to hydrocarbon vehicles.

Let's just face it, hydrogen as a fuel isn't much of a good idea for everyday use. Sure, rockets get better specific impulse from using it as propellant, but we don't exactly commute using rockets nowadays.

The storage would likely be underground for safety reasons. 

Besides the only alternate sources of energy we can consider that has enough energy density other than renewable sources (wind,water,air,geothermal), nuclear and non renewable sources (gasoline, Diesel, etc) is hydrogen. Unless you have a better idea.

[shynung]

Just now, ZooNamedGames said:

The storage would likely be underground for safety reasons. 

Besides the only alternate sources of energy we can consider that has enough energy density other than renewable sources (wind,water,air,geothermal), nuclear and non renewable sources (gasoline, Diesel, etc) is hydrogen. Unless you have a better idea.

I was talking about in-vehicle storage. A vehicle can't drive or fly if it left the fuel tank at home.

Also, I'm sorry, but you're wrong. Hydrogen has worse energy density than gasoline or diesel fuel. A liter of gasoline contains 34.2 MJ of stored energy; that of diesel fuel is 35.8. Hydrogen, pressurized at 700 bar ( about 690 atmospheres), contains only 5.6 MJ.

[ZooNamedGames]

12 minutes ago, shynung said:

I was talking about in-vehicle storage. A vehicle can't drive or fly if it left the fuel tank at home.

Also, I'm sorry, but you're wrong. Hydrogen has worse energy density than gasoline or diesel fuel. A liter of gasoline contains 34.2 MJ of stored energy; that of diesel fuel is 35.8. Hydrogen, pressurized at 700 bar ( about 690 atmospheres), contains only 5.6 MJ.

I'm not disagreeing about it being weaker, but we need an alternative power source. Something not Gasoline or diesel. Hydrogen is the best solution if you don't want to go nuclear, solar, water, wind or geothermic

[DaMachinator]

We should all just fly around in STOL autogyros.

[shynung]

7 minutes ago, ZooNamedGames said:

I'm not disagreeing about it being weaker, but we need an alternative power source. Something not Gasoline or diesel. Hydrogen is the best solution if you don't want to go nuclear, solar, water, wind or geothermic

And why is that? We started the discussion of automated flying cars. Why does it have to deal with hydrogen? Standard-issue fuels like gasoline, diesel, and jet fuel works well enough.

Just so you know, outside rocketry applications, hydrogen isn't some wonder fuel that magically improves the performance/efficiency of anything it is fueled with. Besides difficulties in storing and handling them, it doesn't carry anywhere near the energy density. For a daily driver/flyer, it's impractical, full stop. I don't see why we should even bother.

Also, @DaMachinator, I would definitely fly around in an autogyro. If I have one, that is.

Edited August 1, 2016 by shynung

[ZooNamedGames]

10 minutes ago, shynung said:

And why is that? We started the discussion of automated flying cars. Why does it have to deal with hydrogen? Standard-issue fuels like gasoline, diesel, and jet fuel works well enough.

Just so you know, outside rocketry applications, hydrogen isn't some wonder fuel that magically improves the performance/efficiency of anything it is fueled with. Besides difficulties in storing and handling them, it doesn't carry anywhere near the energy density. For a daily driver/flyer, it's impractical, full stop. I don't see why we should even bother.

Why can't we use them? Because we only have 59,064 days approx. until we run out. Not to mention is a polluting substance. They may work well, but it's running out. This is technology that's supposed to step us up, not keep us where we are until we run out and need to panic.

Tell that to various car companies; it's the best solution for power sources outside of renewable sources.

Also with that attitude; you might as well as push us all into a nuclear reactor since there's nothing better than that damn dirty gasoline.