The Naked Scientists

The Naked Scientists Forum

Author Topic: Flying cars  (Read 34617 times)

Offline kalayzor

  • Jr. Member
  • **
  • Posts: 24
    • View Profile
Flying cars
« Reply #50 on: 27/11/2007 22:01:12 »
So, from my position, where I have a commercial airport about 4 or 5 miles away, another two about 40 miles away, and one more which (by train) through the city centre is probably about 80 miles away, although taking the ring road around London would be considerably further.

Clearly, those commercial airports presently support city to city traffic, so where would you see my using an airtaxi or flying car?

Airports are away from the areas of large population density (relatively speaking - as in they aren't IN the depths of the city) for practicality (takeoff/landing over obstacles) as well as for noise concerns, right?  In essence, airliners cannot drop you off AT your destination.  That's where airtaxis/etc come in.  The mass transit option just makes things a mite cheaper to travel the distance.

As for where to actually set down...well, the New Hampshire isn't too full of empty space either, save 'tis full of forests, mountains, and lakes rather than houses.  This is, in my mind, the main problem with the system, and why emergencies should not be delegated to computer control.  The best bet you have with an engine failure over that sort of terrain (let's say you're over the middle of a forest) is dropping the aircraft between two trees and whacking off the wings to bleed as much energy as possible without crushing the cabin.  Unless imaging programs get a LOT smarter...I don't think that a computer is going to be able to figure out how to do that (and when to do that) anytime in the near future...not for a good while yet.

It rather depends on the context.  If you are flying in poor visibility, then one way or another, you are going to have to rely on electronic navigation to get you down, or you are dead.  Whether that be MLS, or it be GPS and ground mapping radar, it is not going to be eyeball navigation.

You'll note that I'm not advocating flying by eye and the seat of your pants -- I'm advocating manual control in emergencies.  I also realize that computers do have the advantage under certain circumstances.  The problem is discriminating between the two.  How will the computer know that a field has a drainage ditch in it, a fence at one end, and a set of power lines in the way of a normal approach (let's imagine a power-off landing scenario)?  I can't think of any agency that has mapped the Earth's surface that thoroughly or plans to do so (and add in things every time a farmer adds a wall to his farmland).  I know this would be a heck of a problem over farmland in Britain in especial, given all of the enclosed fields that you guys have.

I realize that if the field's socked in (we're still talking about the farmer's field) and you don't have anything to guide you down, there's going to have to be a way to at least attempt the landing.  In that case, OK, GPS or what have you.  There will have to be a program to check the glide distance of the aircraft (with the measured winds aloft, etc) against possible landing sites and current reported visibility (via empirical tests done on board the aircar by automatics or aviation weather sources...probably the latter) to determine automatic or manual.

Ahhh...sorry about the many and varied CFR (Code of Federal Regulations on aviation in the US) references that I've made.  I didn't realize that you were British...hope that you made them out OK.  Flight training IS indeed cheaper in the states, but I get what you're saying.  Then again, are we also anticipating no shift to alternative energy (and I don't mean ethanol...don't get me started on that one)?  Most of that cost (especially in your flight school's cost) is probably toward buying avgas.  Unfortunately, I doubt that's going to happen anytime soon either (unless a Manhattan project-style commission gets on it).

Hmm...how much would it cost to do a majority of training in the sim, and then take actual flights towards the end of your career?  Sims are actually advocated for their ability to force students to use their instruments and get used to what things look like without the distraction of all of the different sensations of flight (I know, they aren't distractions, I'm a big advocate of flying by the seat of your pants myself (being a glider pilot) -- I just needed a word).  Sim time is accepted for many licenses nowadays (in the US), including power.

As for airspace - we can do better than merely making a mandate -- we can make a all flight in a 20 mile radius of any major airport (class B airspace in the US...I can't find the English equivalent) automatically slaved to computer control, save in case of an emergency under the conditions already discussed (such as an engine failure or something that required an immediate landing off-airport).

Speaking of engine failure, powered aircraft may have the glide ratio of something close to a brick (most still manage a 10:1 L/D at best), but they still have a glide ratio -- they can still be safely landed with a failed engine.  The STOVL aircraft that I'm talking about still have wings -- the most efficient wings that you can get for a good price (I'm not talking wings from something like the eta, but they could probably be designed to a higher standard than, say, a Cessna 172 without too much cost).

In reality, I don't think it should be allowed anywhere - not least because even if the PIC is trained and qualified, how do you ensure they retain consistent experience in flying when all the flying (outside of the once in a lifetime emergency) will be on automatic?

Finally, as noted before -- flight reviews!  You HAVE to take a checkride at least once a year, receive a sim training course/one in reality before being able to fly again...at least in IFR conditions or to/from the middle of no where (can be checked via ownership and locked via computer -- data comes from aviation weather and GPS).
 

another_someone

  • Guest
Flying cars
« Reply #51 on: 28/11/2007 03:23:54 »
Airports are away from the areas of large population density (relatively speaking - as in they aren't IN the depths of the city) for practicality (takeoff/landing over obstacles) as well as for noise concerns, right?  In essence, airliners cannot drop you off AT your destination.  That's where airtaxis/etc come in.  The mass transit option just makes things a mite cheaper to travel the distance.

This is all relative, as you say.

The innermost airport in London is the London city airport, which is well within the metropolitan area of London, intended to service the financial heart of the city.  It is specifically intended only to support STOL aircraft, and only a couple of aircraft types are licensed to use the short runway, and steep approach and take-off required by nearby buildings, not least being the recently built bridge over the river Thames.

The problem with other airports is that the oldest of them, Heathrow, may well have been on the edge of the urban conurbation, but the urban conurbation has since spread, and one of the problems it has is that apart from noise restrictions, it finds it impossible to expand very much simply because of the urban areas that have grown up around it.

Stansted is still relatively away from housing, although whether that will still be the case in two or three decades time is another matter.

Luton airport, which is the airport that is 5 miles from me, was only ever intended as a small regional airport, on the edge of a provincial town.  The size of the airport has grown (at least in terms of passenger numbers - it still only has one runway, although the runway has been lengthened); but more critically, the town and the surrounding smaller towns have grown (partly taking on the overspill from the London area, which is only 40 miles away, and Luton airport itself sells itself as an airport for London).

Another problem with major commercial airports is that they are not very friendly for small aircraft to land in - so using small aircraft (aircars) to take you to a major commercial airport would present problems in that regard.  There are a number of issue.  Firstly, simply the problem of landing charges (they are geared for the big carriers, who can afford to pay them).  This is linked also to the shortage of landing/takeoff slots that are always a part of a busy airport, and these landing and takeoff slots are sold between the major carriers themselves for very substantial sums of money.  There is no way a small aircar owner would be able to play in the same league.  Then there is also the problem of separation - not least the matter of avoiding the wingtip vortexes of the aircraft ahead (the wingtip vortexes of a major airliner can tear a small plane apart if it gets too close - even the airliners themselves have to be careful, and at least one air accident in New York, shortly after 9/11, which was feared to be another terrorist attack, turned out to be one airliner getting caught in the vortexes of the preceding airliner - how much more of a problem if you are talking about a very much smaller aircraft).

As for where to actually set down...well, the New Hampshire isn't too full of empty space either, save 'tis full of forests, mountains, and lakes rather than houses.  This is, in my mind, the main problem with the system, and why emergencies should not be delegated to computer control.  The best bet you have with an engine failure over that sort of terrain (let's say you're over the middle of a forest) is dropping the aircraft between two trees and whacking off the wings to bleed as much energy as possible without crushing the cabin.  Unless imaging programs get a LOT smarter...I don't think that a computer is going to be able to figure out how to do that (and when to do that) anytime in the near future...not for a good while yet.

We don't have very many trees (the odd one here or there), but lots of houses.  Landing between houses and, and whacking off the wings to absorb the energy will just not working, not if there is a kiddy playing in the garden of the house whose side you have just demolished to absorb the impact of landing.

Maybe a more practical way to absorb impact is to have very large airbags to absorb landing impact (it will ofcourse have to be quite a complex system, because you will want to reduce forward motion as well as vertical motion).


You'll note that I'm not advocating flying by eye and the seat of your pants -- I'm advocating manual control in emergencies.  I also realize that computers do have the advantage under certain circumstances.  The problem is discriminating between the two.  How will the computer know that a field has a drainage ditch in it, a fence at one end, and a set of power lines in the way of a normal approach (let's imagine a power-off landing scenario)?  I can't think of any agency that has mapped the Earth's surface that thoroughly or plans to do so (and add in things every time a farmer adds a wall to his farmland).  I know this would be a heck of a problem over farmland in Britain in especial, given all of the enclosed fields that you guys have.

I would suggest that the same problem also exists for most humans.  Ask the average Londoner what a drainage ditch in a field looks like, they'd be hard put identify what a drainage ditch looks like (many would be hard put to tell you what a cow looks like).

But if a human can see it, so a computer can see it.  In many ways, it really does not matter matter whether you have identified a wall or a line of trees, or any other projection - if it stands proud of the ground, then it is a potential obstacle, and its not hard for a computer with stereoscopic vision to identify something standing proud of the ground.  And all of this even assumes you can see the ground - if you cannot see the ground, then whether human of computer, you still become dependent on electronic senses, and then a human can't see anything a computer cannot see (laser or radar images will mean the same to both).

Another factor that humans may take into account, but that a computer probably will not, is that landing in a farmers field will very possibly lead you to heavy financial charges from the farmer in order to allow you to retrieve the aircar (it is a problem that balloonists often have problems with - but it does depend on the goodwill of the farmer, which can be variable).

Ahhh...sorry about the many and varied CFR (Code of Federal Regulations on aviation in the US) references that I've made.

Don't worry I knew what CFR's are, even if I don't have ready access to them although I can't say I knew what the acronym stood for.

  I didn't realize that you were British...hope that you made them out OK.  Flight training IS indeed cheaper in the states, but I get what you're saying.  Then again, are we also anticipating no shift to alternative energy (and I don't mean ethanol...don't get me started on that one)?  Most of that cost (especially in your flight school's cost) is probably toward buying avgas.  Unfortunately, I doubt that's going to happen anytime soon either (unless a Manhattan project-style commission gets on it).

Flying is expensive for all sorts of reasons, not just fuel costs (that composes a part of it, but not all).

The cost of maintaining an aircraft in flightworthy condition costs far more than keeping a car in road worthy condition (the margins of safety enforced are far wider, so parts are changed more often).

Some of the costs of flying are down to the small market involved.  There are fewer people buying aircraft, so the economies of scale are less (and again, the greater conservatism in safety standards for aircraft makes getting safety certification for a new aircraft type far more expensive than doing the same for a car, and that cost is shared amongst fewer customers).

But the higher costs of flying also mean that the cost of being a professional flight instructor are higher, so they pass those costs on by charging higher fees for the time (many of them don't make much money out of it, simple because they are using it merely to fund their own hobby flying - but if the demand for trainers increases sharply, then we may have to look at more professional flight trainers, who are seeking to make a reasonable living out of flight training, and so the prices on this front may actually rise rather than fall).

Another big problem in the UK is, as I have said before, one of weather so flight schools have to invest in hardware that is spending a lot of its time on the ground, not earning any money on their investment, simply because the weather is not suitable for flying.  Economies of scale will not alter this.  The only way this will change is to allow all weather training for novice students, but I cannot see this as being feasable.

Hmm...how much would it cost to do a majority of training in the sim, and then take actual flights towards the end of your career?  Sims are actually advocated for their ability to force students to use their instruments and get used to what things look like without the distraction of all of the different sensations of flight (I know, they aren't distractions, I'm a big advocate of flying by the seat of your pants myself (being a glider pilot) -- I just needed a word).  Sim time is accepted for many licenses nowadays (in the US), including power.

It ought to be able to force down prices considerably, as the amount of flying hardware required to be purchased to support a given number of students (and hence a given revenue stream) should be reduced considerably.  The question is still that how you share out the limited amount of flying time available it is still going to be a problem that when you do have a clear flying day, you will want to get as many students as you can into the air on that day.  The problem is that you may have 100 students all on sims, perfectly happily for several weeks, but given a few clear days, days that you cannot necessarily be able to anticipate, you want to take maximum advantage of it, so you want at least 50 of those students in the air how do you do that unless you have purchased the capacity to do it?

As for airspace - we can do better than merely making a mandate -- we can make a all flight in a 20 mile radius of any major airport (class B airspace in the US...I can't find the English equivalent) automatically slaved to computer control, save in case of an emergency under the conditions already discussed (such as an engine failure or something that required an immediate landing off-airport).

I think the term in the UK is 'controlled airspace' although that is not quite the same as a 20 mile radius otherwise, if it were, the few remaining flying schools in the south-east of England would quickly be out of business, and most are within about that range, and if they are just outside of that range, they would quickly end up flying into it.

I really cannot see that even in the case of an engine failure, the switchover to manual is meaningful.  Just imagine the scene where a tired commuter, on his way home from work, gets into his aircar, switches it into auto, and takes off.  Within a few minutes, tired from a days work, he dozes off.  Some time later, he is alerted by an alarm going off telling him there is an emergency (maybe 1000 feet above the ground) he is still half asleep, and trying to make sense of the situation (he has probably lost a couple hundred feet even before he opens his eyes assuming he even wakes to the alarm at all) there will simply not be time for him to make a meaningful assessment of the situation, take the controls, and take corrective action.  Ofcourse, you could mandate that the pilot must be awake and alert at all time but mandating it and making it happen are two different things.  It is a very different situation where you have a pilot that is continually actively controlling the aircraft the whole time, so by definition, he must be alert to his environment the whole way; but that is not what we are talking about.  I suppose you could use a dead man's handle to ensure that there is at least someone awake in the cabin during the entire flight, but awake and alert to their environment are different things (and in theory, the dead man's handle could be held down by an unqualified passenger).

Speaking of engine failure, powered aircraft may have the glide ratio of something close to a brick (most still manage a 10:1 L/D at best), but they still have a glide ratio -- they can still be safely landed with a failed engine.

So do helicopters, if the are quickly switched into autogyration mode.  It is true that the glide ratio of an autogyrating helicopter is still very stead in comparison to a fixed wing aircraft, but the number of potential emergency landing sites that a helicopter can use are so much greater.  The real question one has to ask is not how far it can fly, but what is the probability of finding a suitable landing area in the given available flight time, and if the number of suitable landing sites increases more than offsets the reduction available range in unpowered flight, then the helicopter would still have the advantage.

Finally, as noted before -- flight reviews!  You HAVE to take a checkride at least once a year, receive a sim training course/one in reality before being able to fly again...at least in IFR conditions or to/from the middle of no where (can be checked via ownership and locked via computer -- data comes from aviation weather and GPS).

I don;t know how many registered drivers there are in the UK (or how this will compare to the number of pilots we would expect out of this scheme although I suspect a fair number of car drivers would fail their medical for a pilots licence), but IIRC there are something like 28 million cars in the UK (and one would expect a fair number of people who are licensed to drive who do not own their own car).  Assuming we talk about 20 million people will be licensed to use fly aircars, that is 20 million checkout flights each year that is a lot of capacity to build up.  How many hours do you expect each pilot to be required to take to remain current? (this is time they will have to take out of their busy lives ok, it is is your profession, or your hobby, but not so ok when it is simply a means to an end a way of commuting to and from work)?
 

lyner

  • Guest
Flying cars
« Reply #52 on: 28/11/2007 13:18:39 »
I have skimmed through a lot of the above posts but has anyone mentioned the necessary  safe separation distance  between flying craft so that their turbulence doesn't have a mutual effect?
Bicycles sound very appealing at the moment!
 

another_someone

  • Guest
Flying cars
« Reply #53 on: 29/11/2007 01:54:23 »
I have skimmed through a lot of the above posts but has anyone mentioned the necessary  safe separation distance  between flying craft so that their turbulence doesn't have a mutual effect?

I have mentioned it in two contexts:  the downthrust of helicopters causing problems for aircraft beneath them (but then kayazor rather disapproves of helicopters anyway); and the problems problems of wingtip vortexes of commercial airliners.

The vortexes created by small aircraft are not very significant, unless you get really close up (and in some cases, you could even utilise them to gain benefit, just as a flight of birds can use the wingtip vortexes of the birds ahead of them to improve their own flight efficiency).
 

Offline kalayzor

  • Jr. Member
  • **
  • Posts: 24
    • View Profile
Flying cars
« Reply #54 on: 01/12/2007 04:32:14 »
Before I get into this, sorry about the delay...homework had me laid up all week.

Another problem with major commercial airports is that they are not very friendly for small aircraft to land in - so using small aircraft (aircars) to take you to a major commercial airport would present problems in that regard.  There are a number of issue.  Firstly, simply the problem of landing charges (they are geared for the big carriers, who can afford to pay them).

Aye aye!  You are right to be concerned about safety.  However, do these airtaxis/aircars need to take off from the same runways as large aircraft?  STOVLs/STOLs, right?  Since they're computer controlled in the vicinity of heavy metal for all intents and purposes, we can place them on a separate ramp (which they probably would have to be anyhow) and give them their own separate takeoff area far enough away from the main runway that they can be vectored out of the way of departing/incoming traffic before wingtip vortices become an issue (it wouldn't be that far off, really).

We don't have very many trees (the odd one here or there), but lots of houses.  Landing between houses and, and whacking off the wings to absorb the energy will just not working, not if there is a kiddy playing in the garden of the house whose side you have just demolished to absorb the impact of landing.

Maybe a more practical way to absorb impact is to have very large airbags to absorb landing impact (it will of course have to be quite a complex system, because you will want to reduce forward motion as well as vertical motion).

Obviously, you aren't going to smash your way through houses in order to land.  Killing your aircraft is fine, endangering others isn't so fine.  The only problem with the airbags is that although is helps the pilot/passengers out, it leaves them with an aircraft going at a couple dozen knots!  What if you're landing on muddy/wet terrain too, so wheelbrakes aren't counting for much?  Perhaps a ballistic parachute would prove better in this case - a nice, one-shot, emergency-use-only parachute for the entire aircraft (currently used in general aviation and sold commercially to anyone who wants one).  You'd probably be able to rig up a steering system of sorts (by controlling the risers with a computer to limit control if you get too close to collapsing the thing).

As for control (human v computer), I'd agree that a computer could see it (al la AGM-65A Maverick seekers), but could it do anything with that?  It took a long time to get Mavericks to even be able to track a target that a Weapons Systems Officer (WSO - the backseat weapons guy in a military aircraft) had slaved the TV seeker to.  How would a computer be able to figure out what's what by itself?  I just don't see that happening for a good long while, especially with natural objects at a distance.

As for human judgment on landing in farmer's fields, etc...which would you prefer - less money, or less life?  I know what you mean, though -- glider folks land out a lot, and you get responses from the farmer standing by your cockpit with a burger and a coke in hand or running out to get you with a rock-salt loaded shotgun.  Still, my statement stands.  When you're in an emergency situation, the general reaction is to get "tunnel-vision" of a sort, to focus directly onto fixing the situation at hand.  In this case, it would be getting the aircraft on the ground and, thus, surviving.

So do helicopters, if the are quickly switched into autogyration mode.  It is true that the glide ratio of an autogyrating helicopter is still very stead in comparison to a fixed wing aircraft, but the number of potential emergency landing sites that a helicopter can use are so much greater.  The real question one has to ask is not how far it can fly, but what is the probability of finding a suitable landing area in the given available flight time, and if the number of suitable landing sites increases more than offsets the reduction available range in unpowered flight, then the helicopter would still have the advantage.

Ok, but I'm still going to cite the problems I have with the safety factors and range limitations in rotary-wing aircraft.  I don't think that it is worth it.  A fixed-wing plane will work just as well, and not have said problems.

I don;t know how many registered drivers there are in the UK (or how this will compare to the number of pilots we would expect out of this scheme although I suspect a fair number of car drivers would fail their medical for a pilots licence), but IIRC there are something like 28 million cars in the UK (and one would expect a fair number of people who are licensed to drive who do not own their own car).  Assuming we talk about 20 million people will be licensed to use fly aircars, that is 20 million checkout flights each year that is a lot of capacity to build up.  How many hours do you expect each pilot to be required to take to remain current? (this is time they will have to take out of their busy lives ok, it is is your profession, or your hobby, but not so ok when it is simply a means to an end a way of commuting to and from work)?

Hmm...what about not having to maintain any hours...just pass the test?  Given the low amount of flying required, it wouldn't be too rigorous - just enough to make sure that you'll be able to fly in an emergency, since that's what we're focusing on (and we're imagining that MLS beacons will be installed on rooftops, I think...or something like that).  AKA - lots of short field work/power off stuff/emergency procedures.

Also, massive amount of people needing to take a test...I'd think that the cost would go down.

The cost of maintaining an aircraft in flightworthy condition costs far more than keeping a car in road worthy condition (the margins of safety enforced are far wider, so parts are changed more often).

Some of the costs of flying are down to the small market involved.  There are fewer people buying aircraft, so the economies of scale are less (and again, the greater conservatism in safety standards for aircraft makes getting safety certification for a new aircraft type far more expensive than doing the same for a car, and that cost is shared amongst fewer customers).

But the higher costs of flying also mean that the cost of being a professional flight instructor are higher, so they pass those costs on by charging higher fees for the time (many of them don't make much money out of it, simple because they are using it merely to fund their own hobby flying - but if the demand for trainers increases sharply, then we may have to look at more professional flight trainers, who are seeking to make a reasonable living out of flight training, and so the prices on this front may actually rise rather than fall).

Another big problem in the UK is, as I have said before, one of weather so flight schools have to invest in hardware that is spending a lot of its time on the ground, not earning any money on their investment, simply because the weather is not suitable for flying.  Economies of scale will not alter this.  The only way this will change is to allow all weather training for novice students, but I cannot see this as being feasable.

I really cannot see that even in the case of an engine failure, the switchover to manual is meaningful.  Just imagine the scene where a tired commuter, on his way home from work, gets into his aircar, switches it into auto, and takes off.  Within a few minutes, tired from a days work, he dozes off.  Some time later, he is alerted by an alarm going off telling him there is an emergency (maybe 1000 feet above the ground) he is still half asleep, and trying to make sense of the situation (he has probably lost a couple hundred feet even before he opens his eyes assuming he even wakes to the alarm at all) there will simply not be time for him to make a meaningful assessment of the situation, take the controls, and take corrective action.  Ofcourse, you could mandate that the pilot must be awake and alert at all time but mandating it and making it happen are two different things.  It is a very different situation where you have a pilot that is continually actively controlling the aircraft the whole time, so by definition, he must be alert to his environment the whole way; but that is not what we are talking about.  I suppose you could use a dead man's handle to ensure that there is at least someone awake in the cabin during the entire flight, but awake and alert to their environment are different things (and in theory, the dead man's handle could be held down by an unqualified passenger).

It's too late (as in 11:25PM and I need sleep) for me to think too very straight.  I'll get back to considering these tomorrow, OK?
 

another_someone

  • Guest
Flying cars
« Reply #55 on: 01/12/2007 05:57:21 »
Before I get into this, sorry about the delay...homework had me laid up all week.

No problem - real life has a habit of getting in the way of things.

Aye aye!  You are right to be concerned about safety.  However, do these airtaxis/aircars need to take off from the same runways as large aircraft?  STOVLs/STOLs, right?  Since they're computer controlled in the vicinity of heavy metal for all intents and purposes, we can place them on a separate ramp (which they probably would have to be anyhow) and give them their own separate takeoff area far enough away from the main runway that they can be vectored out of the way of departing/incoming traffic before wingtip vortices become an issue (it wouldn't be that far off, really).

I suspect from the perspective of terrorist security also, as well as not mixing international air traffic (with passengers that have cleared customs) with domestic traffic (that has not cleared customs), would all demand that these kind of air taxis would land in a nearby parking lot, and passengers then ferried to the departure terminals.

The problem is still where is land going to be made available for these extra runways.  Even commercial runways, where large amounts of big corporate vested interests are driving the process, can still take 5 or more years of political haggling (and this is before even the first clod of earth is turned) to get off the ground.  We are talking here not about one runway, but a whole infrastructure, and no currently established commercial vested interested to drive it.

Obviously, you aren't going to smash your way through houses in order to land.  Killing your aircraft is fine, endangering others isn't so fine.  The only problem with the airbags is that although is helps the pilot/passengers out, it leaves them with an aircraft going at a couple dozen knots!  What if you're landing on muddy/wet terrain too, so wheelbrakes aren't counting for much?  Perhaps a ballistic parachute would prove better in this case - a nice, one-shot, emergency-use-only parachute for the entire aircraft (currently used in general aviation and sold commercially to anyone who wants one).  You'd probably be able to rig up a steering system of sorts (by controlling the risers with a computer to limit control if you get too close to collapsing the thing).

My concern with parachutes is that they may be fine in relatively uncrowded airspace, but they don't give you very much control over your flight path (some control, yes - but very rudimentary); and when you have a lot of other air users around you, and have to be very precise both in your descent path through the traffic, and the point on which you hit the ground, I don't think parachutes would achieve that (think about the precision with which the old Apollo space craft landed on chutes, and the comparable precision of a shuttle).

With regard to air bags - I was not thinking of air bags within the aircraft (although that may be a different issue), but air bags outside of the aircraft, actually absorbing the impact velocity of the aircraft on an emergency landing.

As for control (human v computer), I'd agree that a computer could see it (al la AGM-65A Maverick seekers), but could it do anything with that?  It took a long time to get Mavericks to even be able to track a target that a Weapons Systems Officer (WSO - the backseat weapons guy in a military aircraft) had slaved the TV seeker to.  How would a computer be able to figure out what's what by itself?  I just don't see that happening for a good long while, especially with natural objects at a distance.

The Maverick has a long history, and things have moved on by leaps and bounds (compare to a cruise missile yes cruise missiles do make mistakes, but so do humans (and in many cases, the fault is not with the cruise missile hitting the wrong building, but with human error selecting the wrong building).  We can send unmanned missions to far off planets, and land on the planet without a human being anywhere near by.

Bear in mind that a civilian emergency landing system is very different from a battlefield weapon.  Landing strips are not trying to disguise themselves, or avoid detection; and even if the landing system happens to land you in a different field than the one you first thought of, it does not matter so long as it safely gets you down (somewhat different from hitting the wrong target the landing system can afford to err on the side of safety, and ignore something it is dubious about and move on to something else).

As for human judgment on landing in farmer's fields, etc...which would you prefer - less money, or less life?  I know what you mean, though -- glider folks land out a lot, and you get responses from the farmer standing by your cockpit with a burger and a coke in hand or running out to get you with a rock-salt loaded shotgun.  Still, my statement stands.  When you're in an emergency situation, the general reaction is to get "tunnel-vision" of a sort, to focus directly onto fixing the situation at hand.  In this case, it would be getting the aircraft on the ground and, thus, surviving.

Sounds nice in theory, but in practice, my observation of human nature is that anything about which you can say that people will behave in a particular way, will at most be true for 90% of the people, and will be wholly false for the other 10%.

It is not that when people are given a choice between paying up, or getting killed, they will choose to get killed (maybe 1 in 10,000 might even prefer that, but it is not something one  would normally expect), but rather a judgement of what risks they might take (are they going to land safely, but expensively, in a field right beneath them; or will they risk extending the glide in the hope they might be able to land somewhere cheaper, but further away and maybe that risk simply does not pay off).

Hmm...what about not having to maintain any hours...just pass the test?  Given the low amount of flying required, it wouldn't be too rigorous - just enough to make sure that you'll be able to fly in an emergency, since that's what we're focusing on (and we're imagining that MLS beacons will be installed on rooftops, I think...or something like that).  AKA - lots of short field work/power off stuff/emergency procedures.

If we are talking about a fully automated system, then I am not even sure why one needs to pass a test in the first place; and if the idea is that passing a test 10 years ago, with no practical experience, or even refresher courses in between, will have any meaning at all in 10 years time, then I would have to seriously doubt it (rather like all the people who passed all sorts of exams at school, but 10 years later, never having used any of the material in real life, have totally forgotten all the material they crammed for to get through the exam).


It's too late (as in 11:25PM and I need sleep) for me to think too very straight.  I'll get back to considering these tomorrow, OK?

Look forward to your responses when you have the time, and sleep.
 

Offline kalayzor

  • Jr. Member
  • **
  • Posts: 24
    • View Profile
Flying cars
« Reply #56 on: 02/12/2007 14:52:04 »
The problem is still where is land going to be made available for these extra runways.  Even commercial runways, where large amounts of big corporate vested interests are driving the process, can still take 5 or more years of political haggling (and this is before even the first clod of earth is turned) to get off the ground.  We are talking here not about one runway, but a whole infrastructure, and no currently established commercial vested interested to drive it.

What about private interests?  Hotels operate airport parking lots, and it wouldn't be that much of a leap to dedicate that same area to a small runway (100ft or less) and parking ramp.  True, they'd have to go through certification and all, but it would get them money...a decent amount too...

My concern with parachutes is that they may be fine in relatively uncrowded airspace, but they don't give you very much control over your flight path (some control, yes - but very rudimentary); and when you have a lot of other air users around you, and have to be very precise both in your descent path through the traffic, and the point on which you hit the ground, I don't think parachutes would achieve that (think about the precision with which the old Apollo space craft landed on chutes, and the comparable precision of a shuttle).

With regard to air bags - I was not thinking of air bags within the aircraft (although that may be a different issue), but air bags outside of the aircraft, actually absorbing the impact velocity of the aircraft on an emergency landing.

If you're using a chute, your aircraft has dropped out of the airway due to a lost engine.  You're away from any lines of aircar traffic, and there simply isn't enough GA traffic to crowd up the skies to the extent where ballistic parachutes would create a hazard.  I do see your argument about needing precision, though -- especially for a power-off landing in within city limits...which I'd trust to a computer-controlled glide landing to the top of a building or down to the street (yes, I know that there are cars below, but would you rather plow into an office building?).  It depends on how large the wingspan is (which is what nullifies the housing development landing scenario - the wings aren't wide enough to cause that sort of trouble - not unless you're talking 15+ meters).

Airbags on aircraft...while that would provide some amount of cushioning for the aircraft/object impact, I'm thinking of how it would impact the aircraft's fuel capacity.  If you stuff them into your standard wings, you decrease the amount of fuel that you can carry (which is something you don't want to decrease if you want this to be commercially viable...or we could use a permanent magnet to generate a current and use that to power the aircraft (or some other alternative power source)).  I'd mark it as a possibility.

Which brings me to a previous argument that you brought up -- the switchover from computer to manual.  Now that I'm thinking about it more, I guess you could make something with a laser rangefinder and an optical sensor.  It'd be a fun moment of computerized photo analysis, but it could be done.  You'd have to tackle some extensive R&D work on that, though, to troubleshoot, though.  Not that that would be a problem...it would just be another cost.

If we are talking about a fully automated system, then I am not even sure why one needs to pass a test in the first place; and if the idea is that passing a test 10 years ago, with no practical experience, or even refresher courses in between, will have any meaning at all in 10 years time, then I would have to seriously doubt it (rather like all the people who passed all sorts of exams at school, but 10 years later, never having used any of the material in real life, have totally forgotten all the material they crammed for to get through the exam).

You're misunderstanding me.  Link the two thoughts of the initial test and the annuals together!  You have to pass the initial test, and then annuals to keep you up to scratch.  However, if a computer-guided landing system -- for landing virtually ANYWHERE (perhaps an incorporation of topo data with GPS and the rangefinder/optical analysis package that I speculated about earlier, or if you have an idea to that end) -- can be made, I'll concede the manual control point.
 

another_someone

  • Guest
Flying cars
« Reply #57 on: 02/12/2007 19:22:58 »
What about private interests?  Hotels operate airport parking lots, and it wouldn't be that much of a leap to dedicate that same area to a small runway (100ft or less) and parking ramp.

Not here they don't.  The only airport parking one has is provided by the airport authorities themselves (often in multi-storey car parks).

If you're using a chute, your aircraft has dropped out of the airway due to a lost engine.  You're away from any lines of aircar traffic, and there simply isn't enough GA traffic to crowd up the skies to the extent where ballistic parachutes would create a hazard.

Not sure what you mean by 'away from any lines of aircar traffic'?

The original raison d'etre that was proposed for the aircar (my own arguments were slightly different, but my own arguments did not require high altitude flight at all) was to allow 3 dimensional traffic to alleviate the congestion of a 2 dimensional road network.  If one follows this line of argument, then one can reasonably expect a fairly congested airspace, and expect that when a chute opens, you will have a high probability of another aircar beneath you, and another close behind you.

  I do see your argument about needing precision, though -- especially for a power-off landing in within city limits...which I'd trust to a computer-controlled glide landing to the top of a building or down to the street (yes, I know that there are cars below, but would you rather plow into an office building?).

Landing on any road around here, other than in the early hours of the morning, before dawn, would guarantee taking out about a dozen cars beneath you - that is a lot of potential casualties if it is just to save the pilots life.  The only safe place to land would be in an open field (a playing field, park, or small farm).

Airbags on aircraft...while that would provide some amount of cushioning for the aircraft/object impact, I'm thinking of how it would impact the aircraft's fuel capacity.  If you stuff them into your standard wings, you decrease the amount of fuel that you can carry (which is something you don't want to decrease if you want this to be commercially viable...or we could use a permanent magnet to generate a current and use that to power the aircraft (or some other alternative power source)).  I'd mark it as a possibility.

Not in the wings - insufficient structural strength - the only place is built under the fuselage itself (possibly even blasting the underside of the fuselage skin itself into the ground beneath).

The whole point about airbags is that they can be very compact when not in use - the size comes from when it becomes inflated by explosives.

Which brings me to a previous argument that you brought up -- the switchover from computer to manual.  Now that I'm thinking about it more, I guess you could make something with a laser rangefinder and an optical sensor.  It'd be a fun moment of computerized photo analysis, but it could be done.  You'd have to tackle some extensive R&D work on that, though, to troubleshoot, though.  Not that that would be a problem...it would just be another cost.

Much of this kind of work is already being undertaken for R&D the DoD is doing for fully automated vehicles (aircraft and ground vehicles).  In a different context, we already have (albeit, rather primitive) cybercars that are self guiding, although only under limited environments.  There is a lot of commercial and military interest in fully automated transport guidance systems.

In terms of cost - yes, it is an issue, but one has to separate one off costs from ongoing costs (and there is very little political cost to this kind of R&D, unlike the political costs involved in land usage issues).

 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #58 on: 25/01/2009 16:20:45 »
You are cordially invited to see my flyable automobile project at
newbielink:http://www.strongware.com/dragon [nonactive]
 

lyner

  • Guest
Flying cars
« Reply #59 on: 25/01/2009 17:10:58 »
You are cordially invited to see my flyable automobile project at
http://www.strongware.com/dragon
How does it drive? I imagine the suspension would need to be tougher and heavier than for a normal aircraft.

It sounds to me very much along the lines of the 'amphicar' which is made locally. The amphicar is not too good to drive and is not a satisfactory water craft.
What's wrong with a decent public transport system and hired vehicles each end?
I think that too many of the contributions to this thread show the unhealthy influence of Boys' Sci Fi comics. I just would not like the thought of enthusiastic clowns buzzing around over my house. The local flying club are not allowed to fly over towns with their most basic aircraft. I'd lie to keep it that way.
 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #60 on: 25/01/2009 17:27:06 »
OBTW, StrongMobiles are designed for quieter flight with ducted fans and automotive mufflers, so they will not "buzz". These features are intended to provide nice for airport neighbor friends.
 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #61 on: 25/01/2009 17:30:27 »
You are cordially invited to see my flyable automobile project at
newbielink:http://www.strongware.com/dragon [nonactive]
How does it drive? I imagine the suspension would need to be tougher and heavier than for a normal aircraft.
The design calls for Commercial-Off-The-Shelf suspension; the full-size mockup model has Chevrolet Geo suspension and steering.
 

Offline Don_1

  • Neilep Level Member
  • ******
  • Posts: 6890
  • Thanked: 7 times
  • A stupid comment for every occasion.
    • View Profile
    • Knight Light Haulage
Flying cars
« Reply #62 on: 25/01/2009 17:44:09 »
You are cordially invited to see my flyable automobile project at
http://www.strongware.com/dragon

This idea will never take off!!!!
 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #63 on: 25/01/2009 19:07:35 »
I wonder why you make such a comment. I suggest you read the website piece about engineering calculations and focus on theose that deal with analysis of take-off.
(or were you simply making a lame attempt at a joke?)
 

lyner

  • Guest
Flying cars
« Reply #64 on: 25/01/2009 20:43:02 »
Has it actually taken off, though?
 

Offline LeeE

  • Neilep Level Member
  • ******
  • Posts: 3382
    • View Profile
    • Spatial
Flying cars
« Reply #65 on: 26/01/2009 12:22:56 »
That +/- 3 deg pitch range for take-off/landing seems rather wide to me.  I'd also be concerned that with the 6 degree pitch range, when combined with the short arm-length, both the vertical stabilisers and the center section of the horizontal stabiliser will be masked by the wide fuselage/cabin.
 

Offline Karsten

  • Hero Member
  • *****
  • Posts: 701
    • View Profile
    • Fortunately still only a game
Flying cars
« Reply #66 on: 26/01/2009 22:17:53 »
I wonder (and this may have already been discussed, but there is too much to read here ;D):

1) Can a flying car be considered a sustainable alternative to the car for hundred of millions of people?
2) If not, why bother?
3) Ignoring personal safety issues, can a flying transportation vehicle use less energy to be manufactured and for necessary travel purposes (home to work/shopping for supplies/school) than an efficient car and therefor be considered safer for our environment?
4) If not, why bother?
5) Assuming that it will be necessary in the near future for the vast majority of people to move around locally and live in huge cities, what are the benefits of a flying car in this environment?
6) How do you combine the need for road safety with the need for a light vehicle while considering environmental impacts of "space-age" materials?
7) Is this another toy for those who did not get it, do not care, and can afford it?
8) If yes, why bother?
« Last Edit: 26/01/2009 22:21:12 by Karsten »
 

Offline Karsten

  • Hero Member
  • *****
  • Posts: 701
    • View Profile
    • Fortunately still only a game
Flying cars
« Reply #67 on: 26/01/2009 22:25:41 »
You are cordially invited to see my flyable automobile project at
http://www.strongware.com/dragon

To be considered flyable it should at least be able to fly. There are no pictures at that site. Does it fly?

I once designed myself a little airplane. It was supposed to be an ultralight with the steering mechanism more like a hang glider. I built a little model. I called it the "Mayfly". One day it may, but I doubt it. Times have changed.
 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #68 on: 26/01/2009 22:45:29 »
Has it actually taken off, though?
The design process has followed the traditional engineering method of build-up of analysis and evaluation. As a professional aeronautical engineer, I have worked on a few projects for the USAF over a period of some thirty years, in engineering, flight test, and research. The design was tested in wind tunnel and tether/free flight models. The goald now is to re-do the analysis and wind tunnel testing for a prototype.
LeeE: Check the wind tunnel photo of the tufting over the turtledeck to see that the body does not blanket the empennage.
 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #69 on: 26/01/2009 23:00:07 »
I wonder (and this may have already been discussed, but there is too much to read here ;D):

1) Can a flying car be considered a sustainable alternative to the car for hundred of millions of people?
2) If not, why bother?
3) Ignoring personal safety issues, can a flying transportation vehicle use less energy to be manufactured and for necessary travel purposes (home to work/shopping for supplies/school) than an efficient car and therefor be considered safer for our environment?
4) If not, why bother?
5) Assuming that it will be necessary in the near future for the vast majority of people to move around locally and live in huge cities, what are the benefits of a flying car in this environment?
6) How do you combine the need for road safety with the need for a light vehicle while considering environmental impacts of "space-age" materials?
7) Is this another toy for those who did not get it, do not care, and can afford it?
8) If yes, why bother?

Karsten: The StrongMobiles are intended for frequent regional business travelling where the costs of the StrongMobiles are offset by avoiding user costs from a time viewpoint. I really do not foresee much general popular use of flying cars. Like any other business tool or special purpose vehicle, the market will likely be a limited "niche" market.
As an example, consider mail delivery.
 

lyner

  • Guest
Flying cars
« Reply #70 on: 26/01/2009 23:04:13 »
Karsten
I agree that the problem is not only getting what could be a nifty little machine into the air. The real issue is how a system involving much more private flying can be made to work efficiently and safely.
NIMBY i.e. I don't want one landing there or on my roof.
 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #71 on: 27/01/2009 00:14:39 »
Karsten
I agree that the problem is not only getting what could be a nifty little machine into the air. The real issue is how a system involving much more private flying can be made to work efficiently and safely.
NIMBY i.e. I don't want one landing there or on my roof.
I spent most of my USAF career specializing in system safety engineering, that is, working the bugs out of the aerospace systems before they were built. You can see an example of a hazrd report about my StrongMobile designs on my website, relating to birdstrikes.
 

Offline Don_1

  • Neilep Level Member
  • ******
  • Posts: 6890
  • Thanked: 7 times
  • A stupid comment for every occasion.
    • View Profile
    • Knight Light Haulage
Flying cars
« Reply #72 on: 27/01/2009 09:15:48 »
Regardless of whether or not this thing can fly, it would need a clear runway to take off and land. Using public roads would be out of the question. So you will need take-off/landing strips controlled by air traffic controllers. How far would the nearest landing strip be to where you commence and terminate your journey? Say I want to get from Manhattan to Brooklyn or from Greenwich to Kensington. I would probably cover more distance getting from start point to landing strip and landing strip to destination than I would have covered if I had just stayed on the ground and gone straight from one to the other. If I wanted to get from London to Manchester or New York to Washington, I doubt this thing would have sufficient range for a non-stop journey.

There is also the point that we want to get people out of private cars and on to public mass transport, not out of cars into private planes!

I'm sure this thing would be a fantastic toy for the rich. As for the rest of us, as I said, it will never take off. Not a 'lame attempt at a joke', a pun, but a serious one.
 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #73 on: 27/01/2009 14:33:54 »
Regardless of whether or not this thing can fly, it would need a clear runway to take off and land. Using public roads would be out of the question. So you will need take-off/landing strips controlled by air traffic controllers. How far would the nearest landing strip be to where you commence and terminate your journey? Say I want to get from Manhattan to Brooklyn or from Greenwich to Kensington. I would probably cover more distance getting from start point to landing strip and landing strip to destination than I would have covered if I had just stayed on the ground and gone straight from one to the other. If I wanted to get from London to Manchester or New York to Washington, I doubt this thing would have sufficient range for a non-stop journey.

There is also the point that we want to get people out of private cars and on to public mass transport, not out of cars into private planes!

I'm sure this thing would be a fantastic toy for the rich. As for the rest of us, as I said, it will never take off. Not a 'lame attempt at a joke', a pun, but a serious one.

StrongMobiles are designed for flying ranges of 100-600 miles.
When you write "we" are trying to "use mass transit", I wonder which "we", you are writing about; certainly not yours truly!
 

Offline RichStrong

  • Jr. Member
  • **
  • Posts: 10
    • View Profile
Flying cars
« Reply #74 on: 27/01/2009 15:07:24 »
Regardless of whether or not this thing can fly, it would need a clear runway to take off and land. Using public roads would be out of the question. So you will need take-off/landing strips controlled by air traffic controllers. How far would the nearest landing strip be to where you commence and terminate your journey? Say I want to get from Manhattan to Brooklyn or from Greenwich to Kensington. I would probably cover more distance getting from start point to landing strip and landing strip to destination than I would have covered if I had just stayed on the ground and gone straight from one to the other. If I wanted to get from London to Manchester or New York to Washington, I doubt this thing would have sufficient range for a non-stop journey.

There is also the point that we want to get people out of private cars and on to public mass transport, not out of cars into private planes!

I'm sure this thing would be a fantastic toy for the rich. As for the rest of us, as I said, it will never take off. Not a 'lame attempt at a joke', a pun, but a serious one.

Don - My personal tragedy is that, unless I'm paid to fly one of my StrongMobiles by some company, I cannot afford to own one. So, my incentive is only that I might be able to rent one occasionally for fun.
 

The Naked Scientists Forum

Flying cars
« Reply #74 on: 27/01/2009 15:07:24 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums