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Cora – Kitty Hawk's prototype air taxi [video]

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Re: Cora – Kitty Hawk's prototype air taxi [video]

#191

Post by soVeryTired »

manmal wrote: post #188
soVeryTired wrote: post #178

Earlier quoted context omitted.

> On the revenue side, this would replace a two hour trip across a city in traffic with a fifteen minute flight. If a city takes two hours to cross in traffic, that's a clear sign it needs a subway or monorail.

Which both cost billions over billions, and you will not achieve that good connection for the majority of citizens with just one line.

They're expensive, but massively more efficient than other transport. Plus they reduce congestion for anyone who doesn't have easy access.

I could understand why say, Lagos wouldn't have effective mass transit. But it's hard to see why major developed-world cities can't justify the investment.

Re: Cora – Kitty Hawk's prototype air taxi [video]

#193

Post by fastball »

masklinn wrote: post #151
davidedicillo wrote: post #127

Earlier quoted context omitted.

Fortunately, the US isn't the only country on the planet. We could, for instance, get inspiration from those countries that heavily invest in renewable energy.

Most countries are not much better sadly, see https://www.electricitymap.org/?page=map&solar=false&remote=... for EU

Then you'll be happy to hear that they're trialling it in New Zealand first, which according to your map is at about 91% renewables for both islands.

Re: Cora – Kitty Hawk's prototype air taxi [video]

#194

Post by gambiting »

thaumaturgy wrote: post #170
ethagknight wrote: post #71

Earlier quoted context omitted.

Agree with most of what you say, but two open questions- debt alone on $500k amounts to $180/day (10yr am, 6%). Then there’s cost of energy, dead time during recharge, dead leg trips to the next customer, dead let to charge port, maintenance will be rigorous even if the plane doesn’t need it because FAA. Landing fees while be high for urban landing points, plus ground crew at some locations. “Max $100/hr” is way low,…

I'm surprised almost nobody's talking about the relative change in safety yet. Transportation accidents are the leading cause of "unintentional injury" deaths (i.e., not disease, suicide, or homicide) [1]. Although the absolute rates are somewhat low (7.28 fatalities per billion miles for cars and light trucks), you are approximately 100 times more likely to die while driving than flying (table 2 in [1]). [1]: http:/…

These "driving related" injuries and deaths stats are almost always skewed because they include fatalities/injuries for drunk driving and night time driving. Someone only driving to work and back is at an absolutely minuscule risk of injury/death from driving.

Re: Cora – Kitty Hawk's prototype air taxi [video]

#195

Post by simen »

masklinn wrote: post #151
davidedicillo wrote: post #127

Earlier quoted context omitted.

Fortunately, the US isn't the only country on the planet. We could, for instance, get inspiration from those countries that heavily invest in renewable energy.

Most countries are not much better sadly, see https://www.electricitymap.org/?page=map&solar=false&remote=... for EU

Well, they are testing it in New Zealand, which this map shows to be doing extremely well in that regard.

Re: Cora – Kitty Hawk's prototype air taxi [video]

#196

Post by snaily »

fastball wrote: post #169
nradov wrote: post #82

Earlier quoted context omitted.

This aircraft can't take off and land any place that a helicopter can't. It's subject to the same laws of physics, and the same safety and noise regulations. But it may find a niche market by being faster, cheaper, and easier to fly than existing light helicopters.

In addition to ameister14's point, OP was also pointing out that you can glide to land on little to no power, where as a helicopter can't do that.

A helicopter can survive a complete engine out at any point during appropriately chosen flight regimes: https://en.m.wikipedia.org/wiki/Helicopter_height%E2%80%93ve...

In my layman understanding: the heuristic amounts to - at low altitudes you flare and cushion, and at high altitudes you enter autorotation.

Re: Cora – Kitty Hawk's prototype air taxi [video]

#197

Post by fastball »

Someone1234 wrote: post #123
assblaster wrote: post #119

Earlier quoted context omitted.

I don't know for sure, but I think that autorotation of the multiple vertical rotors provide substantial lift even if they're not being actively driven, similar to the tree seeds that autorotate as they fall.

Auto rotation converts air speed (i.e. drag) into lift. That may slightly reduce the relative costs of drag (by providing benefit) but it still has to be overcome by forward momentum.

But that's probably more of an issue for max speed than it is for efficiency, which would explain why it's operating speed is only 150kmph.

Re: Cora – Kitty Hawk's prototype air taxi [video]

#198

Post by danielvf »

pc86 wrote: post #176
thaumaturgy wrote: post #170

Earlier quoted context omitted.

I'm surprised almost nobody's talking about the relative change in safety yet. Transportation accidents are the leading cause of "unintentional injury" deaths (i.e., not disease, suicide, or homicide) [1]. Although the absolute rates are somewhat low (7.28 fatalities per billion miles for cars and light trucks), you are approximately 100 times more likely to die while driving than flying (table 2 in [1]). [1]: http:/…

This is not commercial aviation, this is general aviation (even if it's commercial in nature). GA is more dangerous than driving, roughly comparable to riding a motorcycle, and that's being optimistic.

Strong agreement - no sane company would operate a taxi company at the current General Aviation safety rates. They are going to have to do a whole, whole lot better.

Getting safer seems like it could be possible, but it's going to be an enormous amount of work.

Re: Cora – Kitty Hawk's prototype air taxi [video]

#199

Post by opwieurposiu »

danielvf wrote: post #94
ethagknight wrote: post #71

Earlier quoted context omitted.

Agree with most of what you say, but two open questions- debt alone on $500k amounts to $180/day (10yr am, 6%). Then there’s cost of energy, dead time during recharge, dead leg trips to the next customer, dead let to charge port, maintenance will be rigorous even if the plane doesn’t need it because FAA. Landing fees while be high for urban landing points, plus ground crew at some locations. “Max $100/hr” is way low,…

I'd love a link to that Uber cost number - I'm having a hard time wrapping my head around a car costing more than $100/hr to operate. Even a New York City cab, rented to a driver from a profit making cab company and including the cost of the medallion was $120 for twelve hours of driving. A chunk of a GA aircraft's operational cost is annual maintenance. By flying more per year, the operational cost of an aircraft go…

GA aircraft engines are rarely V6 they are mostly flat 6 or flat 4 for smaller planes. If you go to the website for Lycoming as an example you see they are all flat except for one I4. https://www.lycoming.com/engines

Re: Cora – Kitty Hawk's prototype air taxi [video]

#200

Post by gambiting »

fastball wrote: post #169
nradov wrote: post #82

Earlier quoted context omitted.

This aircraft can't take off and land any place that a helicopter can't. It's subject to the same laws of physics, and the same safety and noise regulations. But it may find a niche market by being faster, cheaper, and easier to fly than existing light helicopters.

In addition to ameister14's point, OP was also pointing out that you can glide to land on little to no power, where as a helicopter can't do that.

Helicopters have a mechanism called autorotation which ensures safe(albeit sharp) landing when the engine fails.
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