4 ms·

One thing that my child mind never accounted for was what happens if my flying car breaks down? In a normal vehicle, it cruises to a stop and gravity keeps it o

One thing that my child mind never accounted for was what happens if my flying car breaks down? In a normal vehicle, it cruises to a stop and gravity keeps it on the ground. That same principle becomes sheer terror when applied to a flying car model.

jader201 3y ago
I mean, there are ways to still mitigate most of the risk. Obviously probably an oversimplification, but I could imagine one or more of the following: - reliable ejection + personal parachute - gliding mechanism - parachute for the vehicle itself The latter two assume the vehicle is fairly small and/or lightweight. Of course, similar to airplanes, multiple redundancies would also mitigate risk. A number of mitigations could help reduce risk below that of driving cars (which can be quite risky in some areas/situations, but we take the risk anyway).
- ta1243 3y ago
  OK, so you eject. You're safe. Meanwhile your 3 ton vehicle plummets onto the people below. I guess that's their own fault for living at street level.
  - WrongAssumption 3y ago
    Absolutely tracks with the car industry’s historical concern for pedestrian safety. None.
    - Abekkus 3y ago
      Pedestrians aren't customers, and deserve to die, and have their land replaced with more highways.
- throwup238 3y ago
  > reliable ejection + personal parachute “Ejection” means a rocket motor under the seat and a 50% chance of spinal damage. Not sustainable for consumers and no one in GA use them outside fighter jets.
  - Teever 3y ago
    You sure that's what 'ejection' means in this context? I was under the impression that the reason ejection from a jet fighter is so strenuous is because the ejector seat needs to eject fast enough to clear the tail of the jet which may be travelling at several hundred miles an hour.
    - throwup238 3y ago
      What else would ejection mean? By definition it's an active source of thrust that is powerful enough to push the pilot clear of the cockpit before they rag doll against the rest of the airplane. Regardless of geometry it has to be powerful enough to overcome the thrust of the airplane and air resistance all within a split second. You can try some sort of mechanical jack in the box mechanism but it's going to have a terrible thrust/mass ratio if it works at all. The vast majority of planes focus on #2, the gliding mechanism, which gives pilots the time to bail out out from a side door and allows for much more forgiving aerodynamics (thrust is up, pilot falls down). For a consumer flying car you're really going to want zero-zero ejection seats that can survive engine failure during takeoff. That's the most dangerous phase of flight and the seat has to be extra powerful (to get the user high enough for the parachute to work).
      - Teever 3y ago
        > “Ejection” means a rocket motor under the seat and a 50% chance of spinal damage Would "Ejection" from a much slower aircraft require a rocket motor that has a 50% chance of spinal damage?
        throwup238 3y ago
        > Would "Ejection" from a much slower aircraft require a rocket motor that has a 50% chance of spinal damage? Yes.
        Teever 3y ago
        Can you explain why an equally damaging ejection system is needed for a jet fighter and a personal flying car type aircraft?
- AnimalMuppet 3y ago
  Parachutes for the plane as a whole are already a thing for very small planes.
  - simne 3y ago
    You will smile, when get know, on many such planes (honesty, not all) Parachutes added because they cannot pass safety regulations :)
BurningFrog 3y ago
You handle it with redundancy. Four smaller motors instead of a single big one, and so on.
bluGill 3y ago
Airplanes do not just fall when this happens. They turn into gliders and you get miles to find a good place to land. Pilots get some training in this.
- simne 3y ago
  Yes and no. Most dangerous part of flight is landing, when plane is under mile mark, and don't have much safety margins. For example, I know few people, crashed when engine broken at about 200m (300feet). Fortunately all alive, but rehabilitation to state when we could drink beer, takes almost half year.
simne 3y ago
This problem is mostly fixed in general aviation, and fix is so successful, planes magnitudes safer than ground vehicles (statistics said, probability of accident on road is about 0.1% but on planes it is 0.0001%). On first page of google search: probability of accident on road "for every 1000 miles driven, your chances of getting into a crash are 1 in 366. Insurance companies report that customers file a claim once every 17.9 years" "Approximately 1.19 million people die each year as a result of road traffic crashes." "Between 20 and 50 million more people suffer non-fatal injuries, with many incurring a disability" https://www.who.int/news-room/fact-sheets/detail/road-traffic-injuries https://www.who.int/news-room/fact-sheets/detail/road-traffi... For planes: "about .01 deaths per 100,000 departures from 225 accidents between 2013 and 2021" “The industry 2022 fatality risk of 0.11 means that on average, a person would need to take a flight every day for 25,214 years to experience a 100% fatal accident,” stated the I.A.T.A. https://www.nbc.com/nbc-insider/how-common-are-commercial-plane-crashes-the-irrational https://www.nbc.com/nbc-insider/how-common-are-commercial-pl... To achieve reliability mostly used two approaches - more strict regulations on design and production (one cannot sale unsafe plane), and same with maintenance. Some countries going even farther then others, for example, all Soviet helicopters required to have at least two engines and to make safe landing on only one. Also, for aviation regulators typical to sacrifice modern hype technologies and be extremely conservative on electronics and software, so planes still achievable but reliable (yes, I don't like npm, I think planes will be hundreds times more dangerous if use npm).
- Veserv 3y ago
  You mean commercial air transport, not general aviation [1]. Private, personal aircraft usage by licensed operators, like how cars are owned and used, generally falls into the general aviation bucket. At 1.5 fatalities per 100,000 flight hours [2] that is less safe than cars per distance unless the average flight speed is ~1000 mph, or around mach 1.3 (it is not, it is probably 1/3-1/5 that). That is despite the vastly greater training required for a pilot’s license. [1] https://www.iaopa.eu/what-is-general-aviation https://www.iaopa.eu/what-is-general-aviation [2] https://www.ntsb.gov/news/press-releases/Pages/NR20211117.aspx https://www.ntsb.gov/news/press-releases/Pages/NR20211117.as...

jader201 3y ago

I mean, there are ways to still mitigate most of the risk. Obviously probably an oversimplification, but I could imagine one or more of the following: - reliable ejection + personal parachute - gliding mechanism - parachute for the vehicle itself The latter two assume the vehicle is fairly small and/or lightweight. Of course, similar to airplanes, multiple redundancies would also mitigate risk. A number of mitigations could help reduce risk below that of driving cars (which can be quite risky in some areas/situations, but we take the risk anyway).

ta1243 3y ago
OK, so you eject. You're safe. Meanwhile your 3 ton vehicle plummets onto the people below. I guess that's their own fault for living at street level.
- WrongAssumption 3y ago
  Absolutely tracks with the car industry’s historical concern for pedestrian safety. None.
  - Abekkus 3y ago
    Pedestrians aren't customers, and deserve to die, and have their land replaced with more highways.
throwup238 3y ago
> reliable ejection + personal parachute “Ejection” means a rocket motor under the seat and a 50% chance of spinal damage. Not sustainable for consumers and no one in GA use them outside fighter jets.
- Teever 3y ago
  You sure that's what 'ejection' means in this context? I was under the impression that the reason ejection from a jet fighter is so strenuous is because the ejector seat needs to eject fast enough to clear the tail of the jet which may be travelling at several hundred miles an hour.
  - throwup238 3y ago
    What else would ejection mean? By definition it's an active source of thrust that is powerful enough to push the pilot clear of the cockpit before they rag doll against the rest of the airplane. Regardless of geometry it has to be powerful enough to overcome the thrust of the airplane and air resistance all within a split second. You can try some sort of mechanical jack in the box mechanism but it's going to have a terrible thrust/mass ratio if it works at all. The vast majority of planes focus on #2, the gliding mechanism, which gives pilots the time to bail out out from a side door and allows for much more forgiving aerodynamics (thrust is up, pilot falls down). For a consumer flying car you're really going to want zero-zero ejection seats that can survive engine failure during takeoff. That's the most dangerous phase of flight and the seat has to be extra powerful (to get the user high enough for the parachute to work).
    - Teever 3y ago
      > “Ejection” means a rocket motor under the seat and a 50% chance of spinal damage Would "Ejection" from a much slower aircraft require a rocket motor that has a 50% chance of spinal damage?
      - throwup238 3y ago
        > Would "Ejection" from a much slower aircraft require a rocket motor that has a 50% chance of spinal damage? Yes.
        Teever 3y ago
        Can you explain why an equally damaging ejection system is needed for a jet fighter and a personal flying car type aircraft?
AnimalMuppet 3y ago
Parachutes for the plane as a whole are already a thing for very small planes.
- simne 3y ago
  You will smile, when get know, on many such planes (honesty, not all) Parachutes added because they cannot pass safety regulations :)

BurningFrog 3y ago

You handle it with redundancy. Four smaller motors instead of a single big one, and so on.

bluGill 3y ago

Airplanes do not just fall when this happens. They turn into gliders and you get miles to find a good place to land. Pilots get some training in this.

simne 3y ago
Yes and no. Most dangerous part of flight is landing, when plane is under mile mark, and don't have much safety margins. For example, I know few people, crashed when engine broken at about 200m (300feet). Fortunately all alive, but rehabilitation to state when we could drink beer, takes almost half year.

simne 3y ago

This problem is mostly fixed in general aviation, and fix is so successful, planes magnitudes safer than ground vehicles (statistics said, probability of accident on road is about 0.1% but on planes it is 0.0001%). On first page of google search: probability of accident on road "for every 1000 miles driven, your chances of getting into a crash are 1 in 366. Insurance companies report that customers file a claim once every 17.9 years" "Approximately 1.19 million people die each year as a result of road traffic crashes." "Between 20 and 50 million more people suffer non-fatal injuries, with many incurring a disability" https://www.who.int/news-room/fact-sheets/detail/road-traffic-injuries https://www.who.int/news-room/fact-sheets/detail/road-traffi... For planes: "about .01 deaths per 100,000 departures from 225 accidents between 2013 and 2021" “The industry 2022 fatality risk of 0.11 means that on average, a person would need to take a flight every day for 25,214 years to experience a 100% fatal accident,” stated the I.A.T.A. https://www.nbc.com/nbc-insider/how-common-are-commercial-plane-crashes-the-irrational https://www.nbc.com/nbc-insider/how-common-are-commercial-pl... To achieve reliability mostly used two approaches - more strict regulations on design and production (one cannot sale unsafe plane), and same with maintenance. Some countries going even farther then others, for example, all Soviet helicopters required to have at least two engines and to make safe landing on only one. Also, for aviation regulators typical to sacrifice modern hype technologies and be extremely conservative on electronics and software, so planes still achievable but reliable (yes, I don't like npm, I think planes will be hundreds times more dangerous if use npm).

Veserv 3y ago
You mean commercial air transport, not general aviation [1]. Private, personal aircraft usage by licensed operators, like how cars are owned and used, generally falls into the general aviation bucket. At 1.5 fatalities per 100,000 flight hours [2] that is less safe than cars per distance unless the average flight speed is ~1000 mph, or around mach 1.3 (it is not, it is probably 1/3-1/5 that). That is despite the vastly greater training required for a pilot’s license. [1] https://www.iaopa.eu/what-is-general-aviation https://www.iaopa.eu/what-is-general-aviation [2] https://www.ntsb.gov/news/press-releases/Pages/NR20211117.aspx https://www.ntsb.gov/news/press-releases/Pages/NR20211117.as...