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Uber Hires Veteran NASA Engineer to Develop Flying Cars

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Re: Uber Hires Veteran NASA Engineer to Develop Flying Cars

#101

Post by grzm »

iaw wrote: post #95
tomcam wrote: post #91

Earlier quoted context omitted.

Upvoted because you're right, but not sure why you felt it necessary to be so hostile

I'm trying to reduce the hostility of my posts. What parts of this do you feel was hostile? Edit: We've hit the end of the reply chain. I see your point about both the opening and closing sentences. Is there any way to say the first one without coming off as hostile? My goal/point was trying to demonstrate how patently wrong the earlier statements were.

My goal/point was trying to demonstrate how patently wrong the earlier statements were.

The evidence or examples you provide should make that clear. Unless you have very strong irrefutable evidence, I would hesitate making any absolute statement declaring someone wrong. What does it gain you? No one likes to be told outright they're wrong. The goal shouldn't be to score points: it should be to reach common understanding.

If this is something you'd like to cultivate further, you might find the references in my profile useful. I refer to them myself regularly.

Re: Uber Hires Veteran NASA Engineer to Develop Flying Cars

#102

Post by zardo »

slededit wrote: post #93
zardo wrote: post #43

Earlier quoted context omitted.

>Flying is not a valid commute solution and never will be because of physics. All things equal, the energy requirements to change elevation will be too great to justify adoption. Which is why birds only ever fly long distances, if it's just a few miles they hop it.

To be fair, birds neither have wheels nor spent most of their evolution in a world with paved roads.

But that doesnt support my snarky comment, so I'll just say all abstractions are leaky and stand by it.

Re: Uber Hires Veteran NASA Engineer to Develop Flying Cars

#103

Post by jessriedel »

iaw wrote: post #84
jessriedel wrote: post #58

Earlier quoted context omitted.

Avoiding a car that crashes in the lane next to you is a lot harder than avoiding a car that falls 100 feet from above. Yet we have multi-lane highways.

That's an asinine statement if I've ever read one. I've been present for 2 highways collisions, avoiding them is super easy. Which is why full lane closures and multi-car pile-ups are as infrequent as they are relative to the frequency of two car accidents. A vehicle that falls from 100 feet above will be accelerating unlike vehicles in an accident on a highway which will rapidly decelerate . Furthermore, you now hav…

I'll assume based on your comments below that you retract the hostile language, so I'll now reply.

As I mentioned earlier, the future we are talking about is one with self-driving cars. The fact that the vehicles are accelerating is much less of a concern than sheer number of seconds allowed for an automated system to take evasive maneuvers. (Coordinating evasion is also much easier for automated systems, and traffic collision avoidance systems are widely used in planes, but this is a secondary point https://en.wikipedia.org/wiki/Traffic_collision_avoidance_sy... )

Your anecdotal experience is not really informative. But what is informative are car and plane accident rates, and the fact that altitude separation for planes is already a standard practice for avoiding collisions.

https://en.wikipedia.org/wiki/Separation_(aeronautics)#Verti...

It is a strong contributor to the fact that mid-air collisions are much more rare than the multi-car pile-ups from having cars in adjacent lanes. As I read your logic, you would assert that planes would be better off flying parallel, all at the same altitude, so as to avoid the need for grade separation. But this is not how air traffic is managed. Yes of course planes are able to separate out further horizontally than cars can (and just as a flying car would be able to), and this reduces the risk of collision debris dropping down on top of any other random plane. But this clearly does not mean that if, for whatever reason, planes became more horizontally restricted, they would make less use of vertical space.

Re: Uber Hires Veteran NASA Engineer to Develop Flying Cars

#104

Post by FabHK »

iaw wrote: post #96
rustmemcpy wrote: post #87

Earlier quoted context omitted.

"The sky is big" is a fallacy in aviation because aircraft don't move unconstrained in 3D space. Typically they are restricted to narrow corridors where collision probability greatly increases. I imagine the same applies to air commute, considering most people will be converging into a small number of waypoints.

That was my assessment as well. Even worse for commuter vehicles because of the various property laws and regional egress requirements.

A couple of points:

a) you don't have to stick to airways. They're largely for ease of planning and navigation with ground-based navigation aids (NDBs, VORs). You can easily fly off airways, and (in general aviation planes during visual flight) nearly always do.

b) with the advent of GPS, "direct" flight routes (not involving airways) are becoming increasingly common.

c) The "big sky" is not a fallacy. Think about it: first, on the ground you can only drive where there are streets. In the sky, you can fly everywhere (even on a 2-D plane), plus then you have the third dimension. There is plenty of space, and congestion won't be a problem unless regulatory/technical issues impose bottlenecks. Airports are natural bottlenecks, but what is envisioned here are VTOL aircraft, so the number of suitable take off and landing places would multiply.

d) The "navigation paradox" [1] is that improved precision in navigation leads to increased risk of collision, because where in the past airplanes where only approximately on an airway (and would most likely miss each other in case of ATC mistake), now they're precisely on the airway (and will collide in case of ATC mistake), see the case of the GOL and Embraer in Brazil [2]. However, that is a shortcoming of current ATC practices, not inherent in flying.

e) I don't understand your point regarding property law. You can hop on a Cessna at Palo Alto or San Carlos airport and fly over the Golden Gate Bridge, San Francisco, Oracle, Stanford, SLAC, San Jose, with no problem. The airspace is there and it's open.

Bottom line: with modern navigation methods, air space congestion will only become a problem after personal aircraft have become tremendously popular and prevalent, if at all.

[1] https://en.m.wikipedia.org/wiki/Navigation_paradox

[2] https://en.m.wikipedia.org/wiki/Gol_Transportes_A%C3%A9reos_...

Re: Uber Hires Veteran NASA Engineer to Develop Flying Cars

#105

Post by FabHK »

jayjay71 wrote: post #20
iaw wrote: post #13

Earlier quoted context omitted.

You are completely right. Shipping automation has a lot of potential. I don't think Uber has any strong competitive advantage in the self-driving space relative to all of the other players. I've been wrong about these things before. The thing that may put them at a disadvantage is their history of ignoring regulations compared to companies like Google. Even if they develop the technology quickly enough they may be sc…

I'm biased because I used to work with many of the people Uber hired for self-driving cars, but they bought really great engineering talent. Great talent doesn't mean much though if the management is bad, and after their whole illegal testing in California debacle it makes me cautious. That said, I didn't realize just how far ahead Google/Waymo is with regards to self-driving cars. If you check out the report of auto…

FWIW, I think highway driving is the easy part (very controlled environment, no sudden cross traffic, etc). City driving is the hard part.

Re: Uber Hires Veteran NASA Engineer to Develop Flying Cars

#106

Post by FabHK »

FnuGk wrote: post #88
snowwrestler wrote: post #74

Earlier quoted context omitted.

The idea is that they are self-driving flying cars, so consumers don't need training. While the physics of flight are more complex than driving, the environment is far less complex (straight-line between points, few obstacles along the way). Flight is better suited to automation, and in fact we already have very reliable autopilots and computer-enhanced airplanes. That said, I think the fuel costs of flying mean it w…

I still do not understand the difference between a flying car and an air plane.

Terrible name, indeed.

Flying car sort of implies:

* can fly and drive on the road.

While there are concepts along those lines (e.g. the Terrafugia Transformation), that's not what this is about.

What distinguishes this new bred of aircraft is:

* VTOL, so not bound to a traditional airport

* simple control ("like a car"), so don't need a pilot. That distinguishes them from a helicopter, which is harder to fly than a fixed wing plane.

* maybe also autonomous flying and collision avoidance, so more like next-gen cars.

I find PEVA (personal electric VTOL aircraft) more descriptive.

Re: Uber Hires Veteran NASA Engineer to Develop Flying Cars

#107

Post by LeifCarrotson »

FabHK wrote: post #38
LeifCarrotson wrote: post #29

Earlier quoted context omitted.

> True, but the economics of energy/housing/transit indicate that there never will be mass adoption if it's also the more expensive option. That depends largely on any negative value that's charged against living in an undesirable location, and on the subjective value a person ascribes to living in a desired location. And that subjective value can remain constant, while the cost of energy and transit decrease, and th…

> on the order of 1,000 kilowatts per hour 1000 kW, or 1000 kWh per h. That's the beauty of P = Power = W/t = Energy / Time.

I was trying to convert gallons of Jet A per hour into something comparable with battery packs which have capacity measured in kWh, and derped hard. Thanks for the correction.

Re: Uber Hires Veteran NASA Engineer to Develop Flying Cars

#108

Post by LeifCarrotson »

iaw wrote: post #46
LeifCarrotson wrote: post #29

Earlier quoted context omitted.

> True, but the economics of energy/housing/transit indicate that there never will be mass adoption if it's also the more expensive option. That depends largely on any negative value that's charged against living in an undesirable location, and on the subjective value a person ascribes to living in a desired location. And that subjective value can remain constant, while the cost of energy and transit decrease, and th…

My formal training is in mechanical engineering and economics. You are completely right about the gradual reduction in cost and increases in efficiency over time for all mechanical technology. There are two things I feel you neglect: a) These increases happen in parallel, meaning that as air vehicles get better so too do ground vehicles. Meaning it's unlikely for the relative advantage of cars to change with technolo…

The point I was trying to make (rather obliquely, I admit) was that as mechanical technology improves the difference between variations ceases to matter. If air transport goes from $500 to $5, compared to ground transport making an even bigger drop from $5 to $0.01, people aren't necessarily going to choose ground over air. An infinitely more efficient $0 walking option exists in both cases. They're going to chose air because $5 isn't enough to care; their time is worth an order of magnitude more than the cost of the transport.
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