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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]

#101

Post by [deleted] »

raducu wrote: post #60
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…

Imagine being able to live 90 miles from a town and commuting in 30 minutes regadless of peak hours. As for the noise, if it can land vertically, I can immagine it making a steep descent on top of a tall building, unloading passengers and then autonomously taking off to pick somone else some other place.

[deleted]

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

#102

Post by lallysingh »

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

AFAIK it's basically just Cirrus that has a parachute system (CAPS in their case). Others don't, and there are plenty of other plane manufacturers with many, many planes in the air.

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

#103

Post by [deleted] »

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…

[deleted]

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

#104

Post by ansible »

From an aircraft design perspective, it is an interesting choice.

I can't help think that this design, with dedicated lift engines is just not very mass efficient. The pylons and the twelve motors also add a lot of drag in horizontal flight, even though they've taken steps to reduce it.

As of today, if I was designing an air taxi from scratch, I'd go with a tail-sitting VTOL, like the E-flite X-VERT:

https://www.youtube.com/watch?v=wFXibbgNix8

For a full-sized aircraft, since you can't vary rotor speed very quickly for large motors, you'd need to add variable pitch propellers. The passengers would sit in a pod which rotates to keep them level during all flight modes.

And, as other commenters have mentioned, a ballisticly-deployed parachute for safety. And maybe emergency landing skids for a horizontal landing if needed.

I know that electric flight is part of the selling point of this design, but I'd still prefer to use fossil fuel for the energy density.

I'd love to try it out if it goes into production!

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

#105

Post by kazinator »

melling wrote: post #76
raducu wrote: post #60

Earlier quoted context omitted.

Imagine being able to live 90 miles from a town and commuting in 30 minutes regadless of peak hours. As for the noise, if it can land vertically, I can immagine it making a steep descent on top of a tall building, unloading passengers and then autonomously taking off to pick somone else some other place.

Yeah, now imagine tens of thousands people an hour being able to do that. I hear they have trains that can do this in far away lands. Trains that go 180 mph. Not in my backyard.

Trains that go 180 mph have a way of draining your pocketbook. If you don't work near a station, or live near one (or, worse, both) you face commuting hassles. You may have to take a train that averages 30 mph as it makes all stops to get to the 180 mph express one.

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

#106

Post by syntaxing »

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 than one large prop like a helicopter?

That being said, I always had a soft spot for aircraft startup after working at one in my younger days. Pretty interesting to see how this ends up especially with Sebastian Thrun on the team.

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

#107

Post by Kequc »

I don't like that they're touting no emissions. Electricity has to be generated and in the US that's mainly coal. Hybrid vehicles are closer to having it right where running the car charges it and you can get by burning significantly less fuel. Strictly electrical has not been shown to be an energy saver or a flag bearer of emissions reduction. In many cases so far it has been a cause of more pollution than modern engines using oil.

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

#109

Post by Retric »

ameister14 wrote: post #95
raducu wrote: post #60

Earlier quoted context omitted.

Imagine being able to live 90 miles from a town and commuting in 30 minutes regadless of peak hours. As for the noise, if it can land vertically, I can immagine it making a steep descent on top of a tall building, unloading passengers and then autonomously taking off to pick somone else some other place.

It won't be 30 minutes. It'd be a few hours. First because they said it could go faster than 150kph, which means it tops out at roughly 90 miles an hour. Second, the range of the thing is about 60 miles, so you'd have to charge it partway.

Swapping batteries is a no brainier for this tech. There is zero reason to have a 500k aircraft waiting around charging vs having 2+ set's of batteries.

Electric cars have a long enough range and are mostly single family so swapping is less useful.

Reserve is a much larger issue, aircraft want to keep ~1hour of reserve these things are starting with less than that.

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

#110

Post by ChuckMcM »

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…

I was thinking something similar, and per the Bend Oregon article that was here before (https://news.ycombinator.com/item?id=16517929) it could make commuting work from further away, although with only 100 mile range that is a bit challenging. (Bend to SF is 500 miles)

I am also wondering about the ergonomics for people who are mobility challenged.

On the plus side, their launch material successfully has gotten me past thinking that they are building quad copters for people into thinking about what they might be used for. The numbers pencil out for relatively short commutes.

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