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by jader201·2y ago·view on hn ↗
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).

3 comments
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.

Absolutely tracks with the car industry’s historical concern for pedestrian safety. None.
Pedestrians aren't customers, and deserve to die, and have their land replaced with more highways.
> 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.

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.

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).

> “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?

> Would "Ejection" from a much slower aircraft require a rocket motor that has a 50% chance of spinal damage?

Yes.

Can you explain why an equally damaging ejection system is needed for a jet fighter and a personal flying car type aircraft?
Because that rate of injury is for trained Air Force pilots in peak physical condition. Once you start ejecting the untrained average people with BMI of 25+ you’re going to need bigger propulsion and they’re going to get injured. The human body simply isn’t made to withstand force.
Parachutes for the plane as a whole are already a thing for very small planes.
You will smile, when get know, on many such planes (honesty, not all) Parachutes added because they cannot pass safety regulations :)