Hacker News Reader

Comment by afgasgbui | Hacker News Reader

>It is considered a potential solution to the strain on existing transport infrastructures.

I'm pretty sure the solution to traffic is not more cars.

Getting a pilot's license costs some $20,000. Fuel costs for small aircraft are sky-high and this thing looks particularly unaerodynamic. Obviously the maintenance costs will be high, since you will be maintaining both a car and an aeroplane. Even if the thing were free most people couldn't afford it.

This will be somewhere between a toy and a business jet. Even assuming it winds up being practical for rich people to use for short jaunts, it will change absolutely nothing for the majority.

I don't want to sound like I'm dismissing this plane. Every pilot knows about the "hundred-dollar hamburger" and flies anyway.

View on HN

> Even assuming it winds up being practical for rich people to use for short jaunts, it will change absolutely nothing for the majority.

Except that the failure mode (unlike for cars on roads) is that this falls out of the sky onto them or their house.

There's reasons why flying has not been opened to a mass market, in the same way that driving has. Mass motor driving is more than bad enough.

Commercial aircraft are the safest mode of transportation. Small aircraft, on the other hand, are deathtraps.

general aviation has a better safety story than driving, when you look at it on a per mile travelled basis.

> general aviation has a better safety story

Quite likely _because_ , unlike driving, the vast majority of passenger-miles in aviation are not undertaken in small vehicles owned by the passenger/driver, or family thereof. i.e. because there aren't lots of "flying cars".

i said general aviation, not commercial aviation; commercial aviation has a better safety story by _every_ metric, by a large margin. general aviation is a lot of small airplanes owned by the 'driver'; akin to 'flying cars' ;-)

Ah ok. Even so, Aviation is much more heavily regulated - compare getting a licence to drive a VW to getting a licence to fly a Cessna. And likely to stay that way, for these safety reasons.

I don't think that's a great metric. I believe by miles traveled, space travel is safer than cars and airplanes.

I'm guessing small planes wouldn't fare so well compared as total number of trips vs trips with an accident.

"deaths per passenger-mile" is a standard metric though (1), and a fully packed long-haul Airbus scores extremely well on it.

I expect it works best as a comparison between modes that travel on the same medium - e.g. Bus beats motorcycle, and they both are found on the same roads. A380 beats Cessna (2)

Space travel is an outlier of course, very dangerous in general, and orbiting isn't traveling to anywhere any meaningful sense. It's just floating in space.

As a mode of transport, it's also not really a major mover of people around the world.

1) "Other comparisons are possible based on passenger trips, vehicle miles, or vehicle trips, but passenger miles is the most commonly used basis for comparing the safety of various modes of travel."

https://injuryfacts.nsc.org/home-and-community/safety-topics...

"Passenger Fatalities per Billion Passenger Miles 2000-2009" https://faculty.wcas.northwestern.edu/~ipsavage/436-appendix...

2) https://www.livescience.com/49701-private-planes-safety.html

> Fuel costs for small aircraft are sky-high

From the BBC link:

The hybrid car-aircraft, AirCar, is equipped with a BMW engine and runs on regular petrol-pump fuel.

Which makes sense. Most general aviation aircraft engines can run on petrol-pump fuel. Some pilots will land on dirt runways next to consumer gas stations. Petrol is cheaper than avgas. You can find videos of bush plane pilots getting a lot of confused on-lookers taking pictures of the airplane crossing the highway and pulling up to a gas pump. [1][2] Many of the experimental bush planes are using car and snow mobile engines Yamaha, Honda, etc... Car engines while not certified for aircraft are generally more fuel efficient, have longer time between rebuilds and operate better at higher altitudes, support higher RPM and have higher output power. The Zenith uses a Honda Accord car engine. [3]

Instead of a fancy flying car, I personally would just get something like Steve Henry's Highlander [4]. It has the Yamaha EPEX modified snowmobile engine and can take off and land in just a little more space than a helicopter. The wings can be removed by one person in 20 minutes.

[1] - https://youtu.be/PUSKBy3flAs?t=927

[2] - https://youtu.be/kSDJJn9lrkg?t=201

[3] - https://www.experimentalaircraft.info/homebuilt-aircraft/vik...

[4] - https://www.youtube.com/watch?v=zk4teJwQ6FI

I was talking about fuel consumption. Most small aircraft run on normal gasoline, but they usually get the equivalent of 10-15 mpg. The Cessna 172, for instance, gets the equivalent of 13 miles per gallon. This vehicle will be worse than that.

I can see why that would be unclear from what I wrote.

"Its creator, Prof Stefan Klein, said it could fly about 1,000km (600 miles), at a height of 8,200ft (2,500m), and had clocked up 40 hours in the air so far."

That sounds like pretty good mileage? Depending on the size of the tank, 1000km is pretty good range for an automobile.

I guarantee you the tank is yuge compared to what you'd find in a normal car. All airplanes have big tanks.

Well no way will a 12,000 gallon tank fit in the car pictured. That's the size of a semi truck trailer.

So to cruise 1000km it has to get way better than 12kpg or whatever.

Something tells me modern BMW engine will be more efficient than 80 year old design powering that Cessna.

The world records for efficiency are here:

https://www.fai.org/records?f%5B0%5D=field_type_of_record%3A...

The world record for the 1000-1750kg weight class is about 16 miles per gallon. That is burning jet fuel rather than ordinary gasoline. 1000 kg is light for a modern car.

There are no aircraft that can compete with a Prius for transporting small numbers of people. There are few that can compete with a Hummer.

(Note that I'm not sure how the records are calculated. There are a lot of relevant variables, most importantly how fast the plane is flying. And I'm not an aeronautical engineer, just a hobbyist.)

EDIT: More information on that record can be found here: https://lift.erau.edu/for-the-record/

I get a slightly different figure of 17-ish mpg. Still pretty bad.

Given how America has tons of infrastructure that serves as runways (all highways), building a flying cars to go from point to point (highway to highway), might make a lot of sense for us, if they could ever truly become autonomous.

The vertical take off stuff and noise are only issues if we try to go from one’s house to Costco, which we really shouldn’t be trying.

Commuting from Philly to NY for work would take one hour if we think about it as highway to highway.

Reply on news.ycombinator.com