Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

m.youtube.com

Post reply on HN
Print view View original

231–240 of 286 posts

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

#231

Post by rounce »

nickbauman wrote: post #209
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…

Maybe remove the rose-colored glasses? 1) 15 minutes? If you flew in a small aircraft regularly, you would know it takes 40-60 minutes to prep a plane from park to airborne in zero traffic. 2) Estimating what the fuel consumption of a small aircraft will be is much, much harder than a surface vehicle. Consider 90% private aviation disasters are a result of pilot error. And 90% of pilot error is in fuel consumption es…

> 15 minutes? If you flew in a small aircraft regularly, you would know it takes 40-60 minutes to prep a plane from park to airborne in zero traffic.

It takes 10-15min (max!) to check a Cessna 152, start, and call for departure clearance. Add on another 10-15min for taxi via the pumps & power+pre-take-off checks, you still have 30min left to play with.

I do agree with your main point that you don't just hop in and turn the key, just think that an hour for all that is taking your sweet time.

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

#232

Post by ryanlol »

blocked_again wrote: post #68
nl wrote: post #48

Earlier quoted context omitted.

Do planes often fall on your head?

Nope. Given the number of planes in the world the probability of that happening is close to Zero. But a lot of birds has pooped on my head. The more KittyHwaks and other mass used flying cars in the air the more the probability of one falling on your head.

I don't think it would be acceptable for an aircraft like this to have a failure rate comparable to a birds poop rate.

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

#233

Post by ryandrake »

clon wrote: post #24
Quanttek wrote: post #17

I must say I'm against this development. First of all, even if electric, this is certainly a very inefficient way of transportation that will 'waste' a lot of energy to transport maybe 4 people. The resulting price of this technology will result in the 99% stuck on the ground while the only te 1% can afford the fare. And even if it becomes a regular mode of transportation, do you really want these planes to fly over…

I agree. People talking about flying cars sound a lot like people demanding faster horses. Or flying horses. I do not think the American dream of a private car scales too well to the future, be it with rubber wheels or tiny propellers. Especially given the population growth. Instead, a brief visit to Singapore, for example, will convince anyone what the future of transportation looks like. A public transport system,…

Great for dense urban areas. Not so much for the remaining 97% of the Earth’s surface. If the future of transportation means packing myself in a crowded city, count me out. I’ll keep my car, thanks.

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

#234

Post by thedrbrian »

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 can autorotate which isn’t as efficient as a glide but will still get one down safely.

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

#235

Post by nradov »

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.

Glide where? This aircraft seems to be targeted toward moving people relatively short distances around dense areas. If you're in a city, look around. How many suitable emergency landing sites do you see with a large, flat, open area without nearby buildings, overhead power lines, or trees? If it loses power at low altitude it's not going to be gliding very far no matter what.

And as others have pointed out, helicopters are perfectly capable of autorotating in case of power loss.

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

#236

Post by JoeDaDude »

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…

As a skydiver, and expecting to see this thing in the small airports where I jumped, I wonder if the autopilot has been trained to avoid open parachutes.

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

#237

Post by ryandrake »

coldcode wrote: post #20
Quanttek wrote: post #17

I must say I'm against this development. First of all, even if electric, this is certainly a very inefficient way of transportation that will 'waste' a lot of energy to transport maybe 4 people. The resulting price of this technology will result in the 99% stuck on the ground while the only te 1% can afford the fare. And even if it becomes a regular mode of transportation, do you really want these planes to fly over…

I don't fear flying cars. I fear flying car crashes. Instead of a fender bender they "land" in your bedroom.

Do you fear small airplanes (which have been flying over your house for almost a century) too?

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

#238

Post by knodi123 »

cbr wrote: post #216
nickbauman wrote: post #209

Earlier quoted context omitted.

Maybe remove the rose-colored glasses? 1) 15 minutes? If you flew in a small aircraft regularly, you would know it takes 40-60 minutes to prep a plane from park to airborne in zero traffic. 2) Estimating what the fuel consumption of a small aircraft will be is much, much harder than a surface vehicle. Consider 90% private aviation disasters are a result of pilot error. And 90% of pilot error is in fuel consumption es…

15 minutes? If you flew in a small aircraft regularly, you would know it takes 40-60 minutes to prep a plane from park to airborne in zero traffic How much of that prep is eliminated by going full automation? Isn't most of the prep the pilot running through a checklist? If there is unavoidable time consuming checking, you could do that in advance and provide the plane as an autonomous taxi. So it shows up, picks you…

> Isn't most of the prep the pilot running through a checklist

Yes, but...

Things like "check your propeller for cracks", or "verify that the control surfaces are actually moving when the controls say they should have moved" should not be skipped.

But you can skip a lot of things just by virtue of this being an electric vehicle - like "visually verify fuel level without using the gauge", or "check oil level", or "test carb heat" or "verify dual magnetos" etc.

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

#239

Post by godelski »

DennisP wrote: post #221
pc86 wrote: post #172

Earlier quoted context omitted.

> The reality is that small piston aircraft are approximately as fuel efficient as the vehicles around you on the highway This is just objectively wrong. Before taking wind into account, a Cessna 172 travels 120kts on a good day and at altitude and appropriately leaned can get down to 8 gallons an hour. 120 nautical miles in 140 miles (less, but benefit of the doubt and all). That's 17.5 miles per gallon. At cruise a…

He specified "general aviation aircraft not designed in the 1950's." The Cessna 172 was first flown in 1955: https://en.wikipedia.org/wiki/Cessna_172 Also, it may be worth taking into account that airplanes travel in straighter lines.

Planes are updated, just an FYI. And most GA aircraft are older. That's how most people fly, by buying an aircraft that is the price of a car (I fly a Cherokee 140. One of the most common aircraft, as with the Skyhawk. My fuel consumption is 8.4gal/hr at 75% mixture and 5.6gal/hr at 50%. Assuming I'm doing an average ground track of 100mph (for easy math), that's 12-18mpg (not counting that I'm 100% rich at TO and LND).

I wouldn't exactly call it fuel efficient, but it isn't burning like an oil refinery on fire either. I also don't pay $5 for gas ($4.09 today, but it isn't uncommon to see it at $3.50). But you do have to consider speed and time to destination if we're going to compare to cars.

One thing to also consider is that avgas is still leaded. And for anyone interested, here is the POH for the Skyhawk[1] and Cherokee[2]. Note that fuel consumption will be in hours or gal/hr when discussing aircraft. Mpg doesn't make as much sense.

[1] https://www.flyingd.net/documents/N739EF_172N_POH_000.pdf

[2] http://wilgroveairport.net/files/Cherokee%20140%20POH.pdf

Disclaimer: Use the POH provided with your aircraft.

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

#240

Post by djrogers »

gambiting wrote: post #201
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.

Nope - NYC used to have a lot of air taxi traffic and after the horrendous accident on the helipad on the top of Pan Am building all air traffic was banned inside the city. Helipads are only allowed along the river. I imagine other cities would impose similar restrictions.

> I imagine other cities would impose similar restrictions.

Imagine what you will, reality still exists. Some places have similar restrictions, some don’t - there are helipads all over Los Angeles for example.

A safer, quieter ‘air taxi’ is more likely to reduce restrictions than add to them.

Post reply on HN