Terrafugia's flying car model has been approved for tests in US airspace • Hacker News Board

Re: Terrafugia's flying car model has been approved for tests in US airspace

#21

Post by dogma1138 » Mon, Dec 21, 2015, 3:14 PM UTC

It's a 1 to 10 scaled model basically a custom themed drone. It will be using batteries rather than the proposed final powerplant and will be most likely crafted out of different materials.

Size doesn't scale, even if the thrust to weight ration will be similar there would be probably 1000 of other differences that will not translate in any meaningful manner to a final full sized model.

Also why do they need permission at all? this is a drone flown in closed private airspace. This is pretty much stretching it as far as veil press releases go.

Re: Terrafugia's flying car model has been approved for tests in US airspace

#22

Post by markbnj » Mon, Dec 21, 2015, 3:17 PM UTC

MrBuddyCasino wrote: post #4

I'm confused, are they powered by batteries or what?

After watching the video on the linked page it seems to be a hybrid gasoline-electric system. But you can be forgiven your confusion, since the video apparently could get some of the other details straight. Moments after show the prop blades extending they described the power head as a "ducted fan," and then a few seconds later showed it scooting through the air with the blades folded.

Re: Terrafugia's flying car model has been approved for tests in US airspace

#23

Post by blktiger » Mon, Dec 21, 2015, 3:24 PM UTC

Xophmeister wrote: post #8

Why would anyone realistically -- i.e., outside the realm of pure fantasy -- want a flying car? People can barely handle one-and-a-bit dimensions at 70mph (i.e., a road with discrete lanes), how well do you think the general population would cope with this? Maybe autonomous flying vehicles would be more practical, but that still leaves the other two main problems wide open: 1. The energy required to keep the vehicle…

It looks like the TF-X is planned to be an autonomous flying vehicle. The user basically just has to tell it 3 landing areas, then the car handles takeoff and landing and calculates whether it has enough fuel/energy to get there. That said, I think we are decades away from making a system like that work. This thing looks like a seriously complicated machine since it's autonomous, has twin helicopter blades for takeoff/landing, a primary engine for cruise, and can drive on the ground. Even if they get all that to work, the maintenance on it is going to be insane.

Re: Terrafugia's flying car model has been approved for tests in US airspace

#24

Post by daveguy » Mon, Dec 21, 2015, 3:34 PM UTC

flying cars will never be a thing because the efficiency of getting an object into the air and keeping it in the air is always going to be more inefficient than rolling it along the ground with wheels. Ok, never is a long time, but not until we have "mr fusions" and more cheap safe power than we know what to do with. We will get automated cars before this (as people have pointed out automation would be required for flight). When automated cars are ubiquitous the efficiency and speed of ground transport will be that much higher and personal flight will be even less attractive.

Re: Terrafugia's flying car model has been approved for tests in US airspace

#25

Post by balabaster » Mon, Dec 21, 2015, 4:15 PM UTC

jacquesm wrote: post #13

balabaster wrote: post #9

Earlier quoted context omitted.

> People can barely handle one-and-a-bit dimensions at 70mph +1 just for this statement alone. So far, statistics say that flying is safer by orders of magnitude than driving your car... that statistic will likely plummet to many orders of magnitude in the opposite direction if flying cars become a thing. If we do end up with flying cars being the norm, I would hope they will be autonomous and not have people manuall…

Correction: statistics say that commercial air travel is safer by orders of magnitude than driving your car. General aviation is already a lot worse than that today, and even pilot certification does not preclude accidents in general aviation. It is the whole process around safety put into practice at commercial airlines and numerous design details present in commercial aircraft that make flying with a commercial car…

You make fair points

Re: Terrafugia's flying car model has been approved for tests in US airspace

#26

Post by ufmace » Mon, Dec 21, 2015, 5:57 PM UTC

jacquesm wrote: post #13

balabaster wrote: post #9

Earlier quoted context omitted.

> People can barely handle one-and-a-bit dimensions at 70mph +1 just for this statement alone. So far, statistics say that flying is safer by orders of magnitude than driving your car... that statistic will likely plummet to many orders of magnitude in the opposite direction if flying cars become a thing. If we do end up with flying cars being the norm, I would hope they will be autonomous and not have people manuall…

Correction: statistics say that commercial air travel is safer by orders of magnitude than driving your car. General aviation is already a lot worse than that today, and even pilot certification does not preclude accidents in general aviation. It is the whole process around safety put into practice at commercial airlines and numerous design details present in commercial aircraft that make flying with a commercial car…

I was going to say something like that, but also, consider the maintenance differences. You can get away with treating a modern car pretty badly, and many people do quite often. What happens when people start putting off standard maintenance for months or years because they couldn't afford it or never got around to it?

Re: Terrafugia's flying car model has been approved for tests in US airspace

#27

Post by matheweis » Mon, Dec 21, 2015, 6:02 PM UTC

dogma1138 wrote: post #21

It's a 1 to 10 scaled model basically a custom themed drone. It will be using batteries rather than the proposed final powerplant and will be most likely crafted out of different materials. Size doesn't scale, even if the thrust to weight ration will be similar there would be probably 1000 of other differences that will not translate in any meaningful manner to a final full sized model. Also why do they need permissi…

> Also why do they need permission at all?

Because in the last few years as the FAA has gone on their power trip to gain control of small unmanned aircraft, they have deemed any and all commercial activity involving model aircraft illegal unless there is an exception in place.

> this is a drone flown in closed private airspace.

According to the FAA, there is no such thing as "closed private airspace" unless you are flying indoors or at least some kind of enclosure.

Re: Terrafugia's flying car model has been approved for tests in US airspace

#28

Post by matheweis » Mon, Dec 21, 2015, 6:34 PM UTC

markbnj wrote: post #22

MrBuddyCasino wrote: post #4

I'm confused, are they powered by batteries or what?

After watching the video on the linked page it seems to be a hybrid gasoline-electric system. But you can be forgiven your confusion, since the video apparently could get some of the other details straight. Moments after show the prop blades extending they described the power head as a "ducted fan," and then a few seconds later showed it scooting through the air with the blades folded.

It appears to me that the "power head" / vtol portion is electric, and that there is a separate - presumably gasoline - "ducted fan" in the rear of the vehicle.

That would eliminate a substantial number of drivetrain complexities for the vtol / early forward portion of flight.

Re: Terrafugia's flying car model has been approved for tests in US airspace

#29

Post by markbnj » Mon, Dec 21, 2015, 7:26 PM UTC

matheweis wrote: post #28

markbnj wrote: post #22

Earlier quoted context omitted.

After watching the video on the linked page it seems to be a hybrid gasoline-electric system. But you can be forgiven your confusion, since the video apparently could get some of the other details straight. Moments after show the prop blades extending they described the power head as a "ducted fan," and then a few seconds later showed it scooting through the air with the blades folded.

It appears to me that the "power head" / vtol portion is electric, and that there is a separate - presumably gasoline - "ducted fan" in the rear of the vehicle. That would eliminate a substantial number of drivetrain complexities for the vtol / early forward portion of flight.

Ah, that makes sense. Thanks for clearing it up. So they use the fans for lift until you get enough forward speed then tuck them.