motorcycle escape chute

Some people try to set land speed records by driving motorcycles on the salt flats. That is probably the safest possible place to attempt such records, but even there, a cyclist who loses control has no good way to stop. If his path is well chosen, he may avoid hitting anything in his multi-mile skid, but stopping somewhat more quickly would be desirable.

I would suggest that the cyclist wear safety harness connected via short rope to a box which contained some rope and a dispensing mechanism (see below). That rope would connect to a second similar, but smaller box. That would in turn connect to a similar third box, which would in turn connect to a parachute.

Each box would be constructed so as to dispense rope from a spool at a controlled tension. The tension for each box should start around 800lbs and increase toward about 1200lbs until the rope pulls tight.

The third box would have about 20 feet or so of rope (it may be possible to omit the spool with that small a quantity). It would begin dispensing rope as soon as the parachute opens. Since the third box box would be small and light, it would quickly accelerate and start pulling with 800-1200lbs of tension on the rope from the second box which would hold 200 feet. That would be on a somewhat heavier spool, but it should be able to get up to speed before the rope from the first box is exhausted. The second box would in turn pull the first box, which would have 5,000 feet of rope. That in turn would pull the driver.

A driver traveling at 249mph would travel about 500 feet with a deceleration of 4g; it would take about 3 seconds to stop. While a 4g deceleration would be uncomfortable, I would expect that with a properly-designed harness it should be survivable. While parachutes are not generally designed to open at high speed, limiting the tension on the rope to 1,200lbs should allow for safe operation.

The third box would contain 5,000ft of rope to allow for the possibility that the driver might be caught on the vehicle. In that scenario, a 1000lb tension would not slow things down nearly as effectively as it would pulling just the driver. A 5,000ft spool should suffice to allow an effective slowdown of a 2,000lb bike. Not exactly a fun maneuver, but still possibly survivable.