Science How i belive a flying car could be built

[fort]

Right now there are too many idiots (in my country some of them never passed the test and just _bought_ the license) with trouble navigating in 1.5 dimensions. I cannot dare imagine what happens if those same idiots go 3-D.

:facepalm:

Yea... unfortunatelly a good public transportation system is communism...

:rofl::rofl:

 

[Hielor]

Well yeah you look at it other way Moller scycar has stated cruise speed of 490 km/h which give it fuel consumption ~60 l per hour and that is comparable to light aircraft with similar mass and performance. Howewer I'd expect it to become serious fuel guzzler if you fly mostly short hops with relatively lot of time spent doing VTOL with engines at near max power.

490 km/h? Really?

That's really fast for a light airplane...

 

[HAL9001]

Right now there are too many idiots (in my country some of them never passed the test and just _bought_ the license) with trouble navigating in 1.5 dimensions. I cannot dare imagine what happens if those same idiots go 3-D.

they only have to drive 1.5d if there are virtual streets in the sky.

 

[Hielor]

they only have to drive 1.5d if there are virtual streets in the sky.

Let me try this again--since you so willfully ignored me the first time I said it:

No.

High-end airplanes have autopilots, that doesn't mean that you don't still need a pilot's license to fly one.

Once you get up in the air, you're no longer driving a car, no matter how fancy your gadgets are. You're flying a plane, and that's a significantly more complex task than you're making it out to be. It doesn't matter how many sci-fi shows you watch, flying an aircraft will never be as simple as that.

 

[HAL9001]

but the car opens something like a driving simulator with a lot of brigdes , and the car than flys like tzhe car in the simulation moves. So you drive on a bridge that doesn't exsist, that's everything.

 

[jedidia]

You're thinking too much anti-gravity. No matter how many autopilots you build in there, the thing will still behave SIGNIFICANTLY different when in the air. For example, you need a more or less constant speed to keep altitude. Now, if the simulator shows you that you are driving on a bridge, that's nice. However, if you, caught in this illusion, slow down to see which crossing to take, you will loose altitude. The only way for the autopilot to prevent this would be to align the thrust more into the vertical direction, which in turn means you'll be using much more fuel.

So if you'll be flying the thing the same way you're driving it, you won't get very far on one tank, for starters. The next thing is, you're thinking too much clear wheather. If you drive on your nicely simulated bridge, and there comes a gust, you might suddenly find yourself beside your simulated bridge, which might be a wee bit confusing. The simulation might compensate to pretend that you never left the bridge, but this would lead to a total detachement of the driver from reality... and you certainly don't want a pilot of a flying vehicle to think that whatever happens around him doesn't matter, or you'll have him flying straight into the next tornado because he doesn't realise that flying is dangerous buisness (yes, more dangerous than driving on the street).

To repeat the major point: No matter how fancy your tech, it won't change that a flying body behaves totally different from an earthbound one. You can't drive it through the air, no matter how good your AI is.

 

[HAL9001]

not in an helicopter. there could be built a special quadrocopter, too, that can hover, hanging left down.

 

[jedidia]

Yes. Maybe. At least until it runs out of fuel, gets hit by a wind gust while being "parked" too close to anything, has a bird flying into a fan, gets a faulty sensory input, has an electrical defect or you have to take a pee, pull over and exit. In any of these cases, any illusion that flying vehicles and cars are the same will be over. you have time to contemplate this until you hit the ground.

 

[earthorbit]

I've once seen a map of the airspace around my hometown. With the next big airport only 20 km away, it was a mess. Altitudes and areas reserved for big planes, then the areas for the sports planes of the nearby airstrip. Airspace reserved for rescue Helicopters... etc

Add 30.000 flying cars to this and there will be serious crahs every day.

 

[Artlav]

a flying body behaves totally different from an earthbound one.

An automobile behaves totally different from a horse or your pair of legs - a horse have a mind of it's own, all you need to do is give the direction and doze off, but a car needs constant attention. There were discussions about dangers of automotive transport back then, but once the cars became practical, the discussion fizzled out.

If a flying car, or some other personal flying device, becomes practical, we will adapt, and our laws will break as well.

I hope.

 

[jedidia]

If a flying car, or some other personal flying device, becomes practical, we will adapt, and our laws will break as well.

certainly, I'm not contesting this point. I'm merely saying that it is an illusion to think that we could build a flying car that handles exactly like a normal car by virtue of a bazillion autopilots.

 

[Wishbone]

If anything, we (capital city dwellers) will envy inhabitants of small towns. The airspace over Moscow, NYC, Washington DC is and will be restricted. What's the reason in building flying cars if they can't be used where they are needed most, and using them where there are no traffic jams?

 

[Moach]

An automobile behaves totally different from a horse or your pair of legs - a horse have a mind of it's own, all you need to do is give the direction and doze off, but a car needs constant attention. There were discussions about dangers of automotive transport back then, but once the cars became practical, the discussion fizzled out.

If a flying car, or some other personal flying device, becomes practical, we will adapt, and our laws will break as well.

I hope.

my thoughts exactly! :thumbup: - i imagine there were also plenty of nay-sayers back then when someone suggested "hey, what if we remove the horse?"

but the car opens something like a driving simulator with a lot of brigdes , and the car than flys like tzhe car in the simulation moves. So you drive on a bridge that doesn't exsist, that's everything.

that's a pretty clever way of discribing it :tiphat:

NOTE: this DOES NOT imply that the system will try to somehow "convince" drivers that they're not really airborne - special training would still be required for even for the most "casual" types of permits (as it is for regular cars) - a flying car IS still an aircraft - an accessible, road-legal one, but an aircraft, nonetheless - and should be treated with all the respect an aircraft demands :hmm:


now... about ducted fans being less efficient, that can't be right :shifty: -
[ame="http://en.wikipedia.org/wiki/Ducted_fan"]look here[/ame] - there is some foundation to that "fairy tale" after all


still, i reckon, turbo-electrical drives must go... and wings must come :yes:
even small wings, which would conventionally imply high stall speeds and poor handling at low velocities, in this case could prove sufficient - since at low speeds, the fans would take charge....


i have devised a new type of engine that could prove more fitting - i call it the "RAPTOR" (Recoil-Action, Pulse Turbine with Overpass Rotor)

it's not a jet turbine, since it works with a discrete compression-expansion cycle, like a good 'ole piston engine - but it removes the major reciprocating mass and most of the excess moving parts in that type of engine :idea:

not a jet, not a piston... it's uhm... something in between :lol:

this very crude animation explains better than i possibly can....

this, i hope, should make for a "best-of-both-worlds" solution.... like a piston engine, the fuel/air mix is compressed in an isolated form - then, the shape of the recoil-valve forces the injector opening to close while the exhaust opens:

hence, a "two-stroke turbine"


this could be mechanically connected to the fans - but still centrally positioned, allowing the engines to work in tandem, so that if one fails, it doesn't matter which, since the other two can seamlessly pick up it's slack....

the wheels would still be electric... but only one engine needs to be running for that.... reducing noise and consumption

 

[jedidia]

:lol:

Now that's a cool design. You, my friend, are a real inventor, I thought your kind has died out half a century ago!

I don't know much about motors and even less about turbines, but two things come to mind:

first is, mounting that valve directly in the ignition zone seems kind of a liability. You'd better find a way to mount it outside, like is customary for piston engines.

second is... you're compressing the air not by igniting, but simpy by pushing it together by raw force. What you got here seems basically a fancy leave blower... are you sure you'll get enough thrust out of this?

Edit: sorry, misinterpreted the design. I thought you're blowing air out at the back for thrust, now I realised that you use the compresor to provide compressed air to the intake chamber, while the rotation of the fan is used to translate the energy to whatever propeller one might want to put on it. This however means that the fan is doing double work: Compressing the air AND powering the propeller. I guess you'll have to do some math and in the end build a prototype engine to find out if it really works...

 

[T.Neo]

What you've described is akin to a piston engine attached to an overgrown turbocharger. It's a somewhat interesting idea.

i imagine there were also plenty of nay-sayers back then when someone suggested "hey, what if we remove the horse?"

The car proved itself. To date, despite Moller International, etc, the flying car has not...

reducing noise and consumption

But not the horrible din that the fans would create? :shifty:

 

[RisingFury]

now... about ducted fans being less efficient, that can't be right :shifty: -
look here - there is some foundation to that "fairy tale" after all

What part of "A ducted fan provides less thrust then a propeller, at the same power" didn't you understand?

That wiki page can say whatever the hell it wants to. Buy a fan, buy a propeller, stick the same battery, speed control and motor on them and you'll see what I'm talking about.

The advantage from the fan comes when the propeller would have to spin so fast that most of it would be near the speed of sound or over it, in the trans-sonic region where aerodynamics goes whacko.

I mean... are you blind? The R-22 helicopter has a 160 horse power engine that doesn't have enough RPMs of power to lift the thing with a fan, but clearly manages to do that with the main rotor.


The main advantage of a fan over propeller is lower cross secion that leads to lower drag and higher RPMs, which result in higher speed when mounted on a plane.

 

[Wishbone]

Re: noise. Just imagine the incessant "BOOM"s when terrorists start diving their HMX-loaded flying coffins into the cities of their choosing. Not joking, sadly enough. You can use concrete barriers against ground cars, but no concrete nor wire can stop the special attack corps...

 

[T.Neo]

When it comes to engines for flying flying cars, I'd go for the GE90-115B. It's quite efficient, and is really impressive in terms of power output and size.

 

[Wishbone]

Doubt that you could term any craft that uses it a "flying car", hur hur...

 

[Sky Captain]

490 km/h? Really?

That's really fast for a light airplane...

Yeah that's what is claimed on their site.

However here is an article suggesting that claimed fuel consumption would be unrealistic for 720 hp cruise power.

http://hamiltonianfunction.blogspot.com/2009/03/moller-sky-car.html