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If just one wheel fails on a car travelling at 100km/h on a road with oncoming traffic you're very unlikely to survive either.

Ntrails 7y ago
A 200km/h head on collision with equivalent modern cars is absolutely survivable. Gravity is pretty potent at getting you moving faster than that, and with extremely uncertain impact point
- underwater 7y ago
  Terminal velocity for a person is around 195kph.
  - Retric 7y ago
    That’s minimum arms out speeds for a human, you can hit 400+kph in a streamlined dive. Failing aircraft can go well past that into ripping of the wings of an aircraft.
- jfindley 7y ago
  I know we're veering somewhat off topic here, but I wonder how true this is in practice? I can't find a lot of testing done at this sort of speed with regular cars. Racing cars and some high-end sports cars are exceptionally strong and allow you to survive a 200 km/h crash - often with only very minor injuries - but I'm really uncertain that this is true for a regular family car. Do you have any further data on this? Given how many regular cars I see driven at this sort of speed when I visit Germany, it'd be interesting to know!
- marcinzm 7y ago
  It's actually a 100km/h collision done twice. Each car goes from 100 to 0, not from 200 to 0. There's twice the energy but it's distributed across the two cars so for each one it's equivalent to hitting a stationary wall. That said, based on this video I don't think an actual 200km/h is anywhere near survivable for the average modern car: https://www.youtube.com/watch?v=LmRkPyuet_o https://www.youtube.com/watch?v=LmRkPyuet_o Possibly higher end sports cars with cages and five point harnesses may fare better.
  - todd8 7y ago
    A 100km/h head-on with a similar car going 100km/h should be similar to a 100km/h head-on collision with a solid concrete wall. However a car traveling at 200km/h has four times the kinetic energy as a car traveling at 100km/h so a collision at that speed is much less likely to be survived than a collision at 100km/h.
    - matt-attack 7y ago
      Wow you are the first person to point out what I’ve been saying for decades. A car hitting another car at the same speed is indistinguishable from a car hitting an immovable wall. Intuition wants to think it’s twice as bad. As an aside can I pose another physics car challenge to you that 100% of people I’ve asked get wrong? You’re the only car at stop light waiting for the light to turn green. You look up in your rear view mirror and see a car bearing down on you presumably with a distracted driver. You know you’re about to get rear-ended. In that split second do you: A) Let up on the brakes and put the car in Neutral or B) slam in the brake as hard as you can.
      - deleted 7y ago
        [deleted]
      - dzdt 7y ago
        The brake will increase survivability for you; neutral will increase survivability for the other driver. What hurts you is the sudden acceleration from the impact, and the brake will decrease that. What hurts the other driver is the sudden deceleration of impact; your brake will make that a harder stop for him while being in neutral would make it a bit less of a hard stop.
        gamblor956 7y ago
        This is backwards. Your car will accelerate suddenly from the impact either way, so you want to increase the time-frame over which the impact forces of the crash are dissipated. If your car is in neutral, then the crash is less severe because only part of the other car hits you before your car starts gets pushed forward, so more of the energy of the impact gets transmuted to accelerating your car and less energy needs to be absorbed by your car's crumple zones. If you slam on the brakes, you effectively turn your car into a stationary object, and that means you and the other car must absorb the full energy of the collision. At collision speeds where survivability is a concern, this usually means the crumple zones are inadequate to absorb the energy of the collision and so more of it gets passed on to your body. Ideally, you would want to accelerate your car as much as possible before the impact to minimize the speed differential. Even a 10mph decrease in the differential has a huge impact on survivability. [Note: bigger cars can survive crashes better because they have more mass they can act as crumple zones to absorb the force of the crash. Older, more rigid cars would frequently survive with limited damage crashes that killed their occupants, at lower average speeds than today, because the cars transmitted more of the impact forces to the occupants. Modern cars are designed to crumple to dissipate impact forces.]
Cthulhu_ 7y ago
If it falls off that axle is only dropping 20cm though, instead of however high this thing flies. Plus, wheels are a lot more solid than props.
marcinzm 7y ago
Wheels are pretty solidly mounted to cars with large pieces of metal. Tires do blow out however then you still have some control. Props on the other hands can have electrical component failures, wiring failures, engine failure, bird ingestion induced failures, control instrument failures, etc. Remember that each vehicle has four times these components (ie: four times the failure rate) and the failure of any is a crash. Just a lot more potential things that can fail and cause a catastrophic accident.
dsfyu404ed 7y ago
Actually you're pretty likely to survive as long as you're wearing a seat-belt and don't crash into anything that only hits the upper half of the cabin (like the side of a big truck)

Ntrails 7y ago

A 200km/h head on collision with equivalent modern cars is absolutely survivable. Gravity is pretty potent at getting you moving faster than that, and with extremely uncertain impact point

underwater 7y ago
Terminal velocity for a person is around 195kph.
- Retric 7y ago
  That’s minimum arms out speeds for a human, you can hit 400+kph in a streamlined dive. Failing aircraft can go well past that into ripping of the wings of an aircraft.
jfindley 7y ago
I know we're veering somewhat off topic here, but I wonder how true this is in practice? I can't find a lot of testing done at this sort of speed with regular cars. Racing cars and some high-end sports cars are exceptionally strong and allow you to survive a 200 km/h crash - often with only very minor injuries - but I'm really uncertain that this is true for a regular family car. Do you have any further data on this? Given how many regular cars I see driven at this sort of speed when I visit Germany, it'd be interesting to know!
marcinzm 7y ago
It's actually a 100km/h collision done twice. Each car goes from 100 to 0, not from 200 to 0. There's twice the energy but it's distributed across the two cars so for each one it's equivalent to hitting a stationary wall. That said, based on this video I don't think an actual 200km/h is anywhere near survivable for the average modern car: https://www.youtube.com/watch?v=LmRkPyuet_o https://www.youtube.com/watch?v=LmRkPyuet_o Possibly higher end sports cars with cages and five point harnesses may fare better.
- todd8 7y ago
  A 100km/h head-on with a similar car going 100km/h should be similar to a 100km/h head-on collision with a solid concrete wall. However a car traveling at 200km/h has four times the kinetic energy as a car traveling at 100km/h so a collision at that speed is much less likely to be survived than a collision at 100km/h.
  - matt-attack 7y ago
    Wow you are the first person to point out what I’ve been saying for decades. A car hitting another car at the same speed is indistinguishable from a car hitting an immovable wall. Intuition wants to think it’s twice as bad. As an aside can I pose another physics car challenge to you that 100% of people I’ve asked get wrong? You’re the only car at stop light waiting for the light to turn green. You look up in your rear view mirror and see a car bearing down on you presumably with a distracted driver. You know you’re about to get rear-ended. In that split second do you: A) Let up on the brakes and put the car in Neutral or B) slam in the brake as hard as you can.
    - deleted 7y ago
      [deleted]
    - dzdt 7y ago
      The brake will increase survivability for you; neutral will increase survivability for the other driver. What hurts you is the sudden acceleration from the impact, and the brake will decrease that. What hurts the other driver is the sudden deceleration of impact; your brake will make that a harder stop for him while being in neutral would make it a bit less of a hard stop.
      - gamblor956 7y ago
        This is backwards. Your car will accelerate suddenly from the impact either way, so you want to increase the time-frame over which the impact forces of the crash are dissipated. If your car is in neutral, then the crash is less severe because only part of the other car hits you before your car starts gets pushed forward, so more of the energy of the impact gets transmuted to accelerating your car and less energy needs to be absorbed by your car's crumple zones. If you slam on the brakes, you effectively turn your car into a stationary object, and that means you and the other car must absorb the full energy of the collision. At collision speeds where survivability is a concern, this usually means the crumple zones are inadequate to absorb the energy of the collision and so more of it gets passed on to your body. Ideally, you would want to accelerate your car as much as possible before the impact to minimize the speed differential. Even a 10mph decrease in the differential has a huge impact on survivability. [Note: bigger cars can survive crashes better because they have more mass they can act as crumple zones to absorb the force of the crash. Older, more rigid cars would frequently survive with limited damage crashes that killed their occupants, at lower average speeds than today, because the cars transmitted more of the impact forces to the occupants. Modern cars are designed to crumple to dissipate impact forces.]

Cthulhu_ 7y ago

If it falls off that axle is only dropping 20cm though, instead of however high this thing flies. Plus, wheels are a lot more solid than props.

marcinzm 7y ago

Wheels are pretty solidly mounted to cars with large pieces of metal. Tires do blow out however then you still have some control. Props on the other hands can have electrical component failures, wiring failures, engine failure, bird ingestion induced failures, control instrument failures, etc. Remember that each vehicle has four times these components (ie: four times the failure rate) and the failure of any is a crash. Just a lot more potential things that can fail and cause a catastrophic accident.

dsfyu404ed 7y ago

Actually you're pretty likely to survive as long as you're wearing a seat-belt and don't crash into anything that only hits the upper half of the cabin (like the side of a big truck)