I think it needs to be asked, has anyone has ever survived free fall from high altitude into water? I know people (not many) have survived free fall from 25,000 feet or so and hitting land, very special circumstances I'll admit, but as far as I know no one is recorded as surviving falling into water. The survivors who hit land fell through dense fir tree limbs down the side of a mountain through deep snow, circumstances that seem unlikely to say the least into water....

people just survive

 

http://www.oddee.com/item_96967.aspx

Hmm, the pressure acting upon entry will be, using the Bernoullis equation, rho*v^2/2. So if you decelerate to 60kph =~ 17mps it would be around 140kPa of pressure, due to your velocity, ignoring any aero/hydrodynamics.

The force acting on the entering surface will be F=p*A, so the smaller the area the smaller the force, intuitively. Lets say you enter with 100cm2 area which gives us approx. 1400N of force.

This means, entering water at 60kph with 100cm2 of impact area ignoring any hydrodynamics creates a force of 1400N, which is like letting a 140kg(308lb) man sit on your feet

But, as soon as you start receiving it it will start decreasing, due to the fact that the water only reacts to your penetration velocity which decreases differentially.

But your body will need to absorb that energy somehow, so your joints, spine, bones will have to process it. You are going to need to "squat" that 300lbs

So even at 60kph the fall looks quite dangerous. And the depth that you might reach. I had an excel macro for this kind of things, namely a bullet entering water, but I am not at my PC right now. This is the last part, the depth

 

It's possible that- due to freak wave/ wind etc conditions, people have survived falling from aircraft into water.

We wouldn't usually know because they would subsequently drown and become fish food.

15 hours ago, John Cuthber said:

It's possible that- due to freak wave/ wind etc conditions, people have survived falling from aircraft into water.

We wouldn't usually know because they would subsequently drown and become fish food.

On 6/4/2010 at 10:36 AM, J.C.MacSwell said:

 

1. Minimize your terminal velocity by spreading your wings so to speak, arms and legs spread out on a plane parallel to the ground. Some clothing may help but will take some skill to maintain position.

 

2. Curl into a cannonball position at the last moment. Enter feet first.

 

3. Pray that the water is really rough, the bigger waves the better, and time it so that you hit the highest, foamiest part of the largest wave on the right angle. (This may require a little skill as well )

 

Do everything right and you may live long enough to drown.

I knew someone would agree...just didn't think it would take 8 years...

The comparison has been made that hitting water is like hitting concrete.

You could, in principle, build a water slide out of concrete.

In principle, the limit to how big a water slide you would survive is based on oxygen deprivation, and the fact that the water would boil at that altitude (rather than the fall).
So, you might get a wave whose surface acted like a giant water slide.

 

However, if you were that lucky, you wouldn't fall out of a plane in the first place.

 

I saw a story about a lady whose parachute did not open and she fell free fall. She still survived, and it was said, because she was lucky to fall on her chest, to make the rib cage take most of the brunt (I suppose it was the ribs, the story did go like that). That was on land. But if it works on land it might also work on water, no?