Free Fall Math and BASE Jumping

Every once in a while, I research something that's just random enough or cool enough or geeky enough to share (like, you know, should you use the definite article when writing about ships, which is way cool).

I'll start you off with the good stuff. Some free fall survival tips:

First of all, you're starting off a full mile higher than Everest, so after a few gulps of disappointing air you're going to black out. This is not a bad thing. If you have ever tried to keep your head when all about you are losing theirs, you know what I mean. This brief respite from the ambient fear and chaos will come to an end when you wake up at about 15,000 feet. Here begins the final phase of your descent, which will last about a minute. It is a time of planning and preparation.

Read the whole thing. It's both amusing and interesting. Now, here's some cool free fall math:

• For a person of average weight, in spread eagle position, terminal velocity is about 120 mph (190 kph).
• An experienced skydiver can attain velocities of 160 mph (250 kph). With training, that can be increased to over 200 mph (320 kph), and the record is over 300 mph (480 kph).
• It takes about 14-15 seconds to reach terminal velocity (120 mph).
• In those 14-15 seconds, the plummeter will have fallen a little over 1,800 feet (550 m).

That means in the Air Pirates' world, where the ships typically fly 1-2 km above the ground, it would take 20-40 seconds for someone to hit said ground.

Now onto BASE jumping. After a short amount of research, I realized I didn't know much about this sport. BASE is an acronym that stands for Building, Antenna, Span, Earth: four categories of objects from which one can jump.

It's basically skydiving without the plane, but it's more dangerous than skydiving. The practical minimum for skydivers to open their parachute is 600 meters, but most BASE jumps are made from less than that. Jumpers have far less time to control their jump, and they usually don't even reach terminal velocity.

That brings me to the other cool thing I learned about: the wingsuit. This is a skydiving suit with added fabric sewn between the legs and between the arms and body. With a wingsuit, the jumper's fall rate drops to an average 60 mph (95 kph) and can get as low as 25 mph (40 kph). It also gives the jumper additional control over their fall, almost to the point of gliding. Some jumpers are even trying to set a record by landing without a parachute.

Check this out:



In Air Pirates, there are 3 scenes where someone jumps or falls from an airship (actually there's a lot more than that, but speed and distance only matter for 3 of them - the rest just die). I even finagled a wingsuit in one of the scenes - some of my protagonists are just too extreme for their own good.