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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]

#241

Post by godelski »

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…

Most GA aircraft don't cost 500k. Just want to put that out there. And I see Skyhawks and Cherokees go for $90-$150/hr.

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

#242

Post by starpilot »

syntaxing wrote: post #106

Can anyone chime in how this aircraft is so energy efficient? It seems like the props on the wing will give a ridiculous amount of drag. Also, one of the key requirements for an energy efficient rear prop plane is super laminar air going to through the rear prop for efficient thrust. The wing design seems to remove this advantage. Edit: Also, I thought smaller props for vertical flight is significantly less efficient…

It's not. It has a range of 60 miles and cruise speed of 93 mph, giving an endurance of 40 minutes. In fixed-wing forward flight, this aircraft is slower than an R22 designed in the 1970s, which can fly 240 miles at 110 mph. I have no doubt that they spent a lot of time optimizing the rotor/disk hubs on this thing for forward flight, but anyway you slice it, it's a very messy wing. That has compromised its performance in both forward and hovering flight, while gaining mechanical simplicity. What this is is a first step, and as battery tech improves, this is the right direction. But the performance is not impressive. This is like a self-driving electric golf cart you ride to get from your doorstep to the entrance of your gated community, in a world of Honda Civics that go 500 miles on a single tank.

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

#243

Post by TylerE »

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.

There is no such thing as "commercial general aviation". Once you're accepting fee-for-service you are a commercial carrier with all the regulations that go along with that.

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

#244

Post by seanmcdirmid »

mnw21cam wrote: post #210
fastball wrote: post #184

Earlier quoted context omitted.

Wait, how does that make sense? What kind of energy if not electrical is coal being used to produce?

Blast furnaces, heating, other chemical processes.

Coal isn't used for heating much in the US, if at all. It is sometimes used for metal production, especially on the east coast, but oddly, not on the west, where hydro is used.

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

#245

Post by jandrese »

willglynn wrote: post #138
ransom1538 wrote: post #70

Small planes have had parachutes for quite some time [1] now and have saved many lives. Why on earth would this company put people up into the air unmanned without one? [Personally, if a parachute was onboard I wouldn't mind jumping into one.] https://www.youtube.com/watch?v=kQyrPVIIQdE

> [Personally, if a parachute was onboard I wouldn't mind jumping into one.] The cabin opens in a clamshell fashion and that appears to be the only way in or out. Opening the canopy mid-flight would probably result in shearing it off once it catches even a small amount of air. From there, you're left with exit point that's ahead of the wing, ahead of the main propeller, and ahead of the rather wide tail section. Mayb…

Maybe if you had the thing switch to hover mode and then jumped off of the front?

I agree that jumping out while it is moving is suicidal.

The CAPS system makes the most sense, especially given the intended market of "person with cell phone and lots of cash to burn". They would be seriously limiting their clients if they required everyone to be jump certified.

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

#246

Post by mrguyorama »

syntaxing wrote: post #155
brunosutic wrote: post #26

A lot of negative comments here. I must say I'm impressed and I applaud these people for building an innovative working thing and taking it to production. No pilot - mind blown. And sure, this might not be the solution to humanity's overall mobility, but heck I can see it being useful in many ways.

I agree that the technology is exciting to see but I think there is a lot of negative comments because there is a lot skepticism (which engineers tend to be including myself due to the nature of our work). That being said, most commercial flights are actually on autopilot during cruise. Pilots can choose to use auto takeoff and landing as well but I believe it requires a specific license and copious amount of paperwo…

>Pilots are important because of liability and federal law

Pilots are important because if the autopilot gets even one little thing wrong it cannot recover and people die. Autopilot is more like "Auto-level and navigate" It is not designed for emergency situations. What kind of license will this vehicle require?

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

#247

Post by godelski »

syntaxing wrote: post #155
brunosutic wrote: post #26

A lot of negative comments here. I must say I'm impressed and I applaud these people for building an innovative working thing and taking it to production. No pilot - mind blown. And sure, this might not be the solution to humanity's overall mobility, but heck I can see it being useful in many ways.

I agree that the technology is exciting to see but I think there is a lot of negative comments because there is a lot skepticism (which engineers tend to be including myself due to the nature of our work). That being said, most commercial flights are actually on autopilot during cruise. Pilots can choose to use auto takeoff and landing as well but I believe it requires a specific license and copious amount of paperwo…

As a pilot and engineer, I think there are good reasons to be skeptical. Here's some of my questions.

1) Can it autorotate? Or in an emergency does it have to glide?

1.5) What's its glide distance? Cruising altitude? There's a lot of drag from those propellers so I imagine its best glide speed isn't great.

2) How are you going to get it in a city? Seems like you're going to have to go to the local GA airport (which are fairly frequent, but you'll still need a normal taxi).

3) There is a really limited range (100km or 60mi) and only goes 150kph (90mph) (I'm guessing max cruising speed, so real world you'll see it going slower, plus you have to consider TO and LND). That's not very far and not very fast.

4) GA is dangerous. How is it communicating with ATC? Can ATC divert it? Will it integrate into the standards (N1234 fly one niner zero). What happens when someone doesn't use the standard (this WILL happen)? So can it fly in class B airspace? I even have questions about class C and D. And how is it going to handle GA aircraft? And if it is in class G how does it deal with that person that isn't using the radio? Does the computer know when its own radio isn't working? And does it know ATC light signals?

5) Who is doing the inspection? In GA we check everything before we fly. Sure you can automate fuel levels, oil, etc. But how are you checking things like propeller or airframe cracks? And is it doing runups? How often?

6) Is it VFR? IFR? What altitude is it flying at? How does it handle cross wind? Which is going to be a big pain if you are flying in cities.

And as to why pilots not only choose, but are required (in the US), to do TO and LND is because that's BY FAR the most dangerous part. I can even tell you I'm thinking a lot more during TO. As a pilot you're constantly thinking about what you're going to do if there is an engine failure. During TO you're under 1000ft and the runway is behind you (you can't turn around). LND, well at least you got the runway ahead of you. Cruising? You got plenty of time to figure out where you're going to go. Pilots aren't just required because liability and federal law, they are required because automation isn't there yet. I can tell you that it is hard to see aircraft in flight. Especially in conditions like sunrises and sunsets. Many accidents happen on clear and sunny days.

There's a lot of things I like about it, but there is legitimately a lot of reason for concern. But it is a prototype after all.

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

#248

Post by starpilot »

danielvf wrote: post #47

Contrary to almost every comment here so far, this is both innovative and energy efficient. Let's talk energy efficiency first. Once it's up in the air, it's has a similar profile to a normal single engine airplane. A Cirrus SR22 can go 1,200 miles on 80 gallons of gas. That's roughly speaking 15 miles per gallon - better than many pickup trucks or large SUVs. And that's while going 180 mph. Slower is more fuel effic…

The performance of this aircraft is piss poor. Why compare it to as SR22? Let's try an R22.

R22

  Range 240 miles
  Speed 110 mph
  Price $250k
Cora

  Range 60 miles (1/4 that of the R22, 1/20th of the SR22)
  Speed 93 mph (half that of the SR22)
  Price ???
This thing is a dog. Cool design, I think it has promise, but let's not pretend this is in any way more than a concept being shoehorned into a niche commercial application.

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

#249

Post by manmal »

soVeryTired wrote: post #191
manmal wrote: post #188

Earlier quoted context omitted.

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.

I think people misunderstand my GP comment. I am VERY pro subway and public transport in general, and I go by bike whenever I can. But there’s a tool for every job, and one subway line won’t solve the same problem a thousand air taxis are going to solve. They don’t even play in the same league. One connects city parts loosely together and relies on other last-mile means of transport (walking, taxi, park&ride, kiss&ride, bike,...); while the other is a whole-in-one, it’s more exclusive (use once per month vs twice per day) and way faster (minutes instead of hours).

Do we need more subways? Heck yes! I want one in my hometown. Do we want air taxis at the same time? Well, why not?

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

#250

Post by decacorn »

nascar_is_bad wrote: post #213
shortoncash wrote: post #131

Earlier quoted context omitted.

It always starts with them before it trickles down to the rest of us. Let's hope they use it and beta test it for us.

Nah, let's hope one of them gets an itch to become public transportation's savior.

it isnt sexy enough and wont make them any return. completely agree with you. its a total waste of resources. never gonna happen
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