Head down tunnel vs. sky

[TheCaver 0]

Ok, so I'm still working on my sit, but I was wondering if head down feels the same in the tunnel as it does in the sky. I was thinking that in the sky, since gravity is actually 'working', then the blood flowing to your head is unimpeded, unlike the tunnel, where you are essentially suspended with gravity still acting on your bloodflow, etc....

Until I can find out for myself :) , maybe someone will enlighten me....

Cheers,

JC

[oosskis 0]

When headdown in the tunnel, the last thing going through your mind is bloodflow to the brain, no pun intended. In that respect, it feels the same. It doesn't matter whether you're in the sky or in the tunnel, you still have one G (one force of Gravity) acting on you. If you are falling at a constant speed in headdown, there is exactly one G on your body. (The force of the air resisting you equals the force of gravity pulling you down) If you are floating at one level in the tunnel, there is also exactly one G acting on you. (Same deal) This only changes, in the sky and in the tunnel, when you accelerate or decelerate (go up or down).
HD in the tunnel can be a lot harder than in the sky and even though you might be fairly decent in the sky at it, doesn't mean you can do it in the tunnel.
How easy it is to learn in the tunnel depends on your height, your weight, your ability level, your talent, your fear of solid walls, your flexibility, your suit, your coach/instructor, the power of the tunnel and the size of the tunnel.
It takes a while to get your reference flying upside down. There is also a progression you need to go through.

"Bodygolfing" isn't as much fun as it sounds. People get pissed when you don't replace your divets.

[Nicodemus 0]

What oosskis said.

[TrickyDicky 0]

Sorry to be a picky bastard, but there is always 9.81g acting on all matter no matter whether you're accelerating, deccelerating or going at a constant speed.

When accel/decel, the resistance forces are less/more than gravity. When constant speed, they are equal and opposite.

UK Skydiver for all your UK skydiving needs.

[Paulipod 0]

Quote

but there is always 9.81g acting on all matter no matter whether you're accelerating, deccelerating or going at a constant speed

Well - if its picky that you want....

9.81 is actually the m/s of 1g - so to be fair a constant falling object is a 1g not 9.81

ie.

g = 9.81 (meters/sec)/sec downward is the acceleration due to gravity



Here's a nice link for those that are really bored and want to know more http://physics.webplasma.com/physics07.html

Bodyflight Bedford
www.bodyflight.co.uk

[oosskis 0]

Quote

Sorry to be a picky bastard, but there is always 9.81g acting on all matter no matter whether you're accelerating, deccelerating or going at a constant speed.

When accel/decel, the resistance forces are less/more than gravity. When constant speed, they are equal and opposite.

Well, if you start being that anal (and incorrect) One force of gravity means that without resistance, you will accelerate at 9.81 m/s^2. If there is no resistance, you, personally, would feel zero g forces. G Forces are determined in relation to yourself. So even though you are accelerating, you feel 0 g. That is why satellites stay in orbit. They are constantly falling but keep missing the planet because they have sideways momentum and no resistance. If you decelerate (while moving Parallel to the pull of gravity), you experience more G Forces, if you accelerate, you feel less.

Also, if we get nitpicky, When skydiving, the force of gravity is less the further you are away from the center of the earth. Also, as you get lower in the atmosphere, even though the force of gravity increases, so does the resistance to the increasing number of air molecules, so you are actually decelerating as you go down. This does not happen in a tunnel. So, pretty much imperceptably, you actually get more "blood rushing to your head" during a skydive than in the tunnel because you are constantly decelerating (after reaching terminal velocity, that is).

I hope that's being picky enough for you.
9-iron out.

"Bodygolfing" isn't as much fun as it sounds. People get pissed when you don't replace your divets.

[rehmwa 2]

Quote

Also, if we get nitpicky, When skydiving, the force of gravity is less the further you are away from the center of the earth. Also, as you get lower in the atmosphere, even though the force of gravity increases, so does the resistance to the increasing number of air molecules, so you are actually decelerating as you go down. This does not happen in a tunnel. So, pretty much imperceptably, you actually get more "blood rushing to your head" during a skydive than in the tunnel because you are constantly decelerating.

this is fun - and, outside, the thicker air (as you descend), in addition to causing a deceleration, will also give more pressure and likely has a physiological effect on oxygenation of the blood. So the blood rushing to your head will.....and so on and so forth

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

[TheCaver 0]

I guess I need to brush up on my physics.

While the explanations above are interesting, I guess I am not getting the science behind it.

If I stand on my head, wind tunnel or not, I would have the definite sensation of blood moving to my head. as my body is stationary while my blood is able to be further acted on by gravity.

If I am in freefall (not in the tunnel), then my blood is actually moving at the same speed as my body correct? (minus the moderate amount caused by air resistance/drag).

Any more thoughts?

JC

[Paulipod 0]

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If I stand on my head, wind tunnel or not, I would have the definite sensation of blood moving to my head

Physics aside - flying headdown in the tunnel doesnt seem to give the sensation of blood rushing to your head.
I think this is probably more down to the fact you are moving your limbs / also not straining to stay there etc... whereas when you do a handstand etc you are stationary with effort involved and not helping your circulation continue.

We have seen alot of headdown over the weekend and not so many bloodshot faces

Bodyflight Bedford
www.bodyflight.co.uk

[oosskis 0]

Quote

Physics aside - flying headdown in the tunnel doesnt seem to give the sensation of blood rushing to your head.
I think this is probably more down to the fact you are moving your limbs / also not straining to stay there etc... whereas when you do a handstand etc you are stationary with effort involved and not helping your circulation continue.

We have seen alot of headdown over the weekend and not so many bloodshot faces

Paulipod is right. All I was trying to say is that the sky is no different from the tunnel. If you are going at a constant speed in the sky (even though it's 300 km/h down) the sensation is exactly the same as in the tunnel. It's a little hard to grasp unless you know the physics behind it, but trust me, you are experiencing exactly the same sensations and forces at terminal velocity in the sky as in the tunnel.
To take it back to some simple physics...
A body moving a a constant speed has no forces acting on it (or they cancel each other out, which is usually the case) In the sky, the force gravity puts on you is cancelled out by the wind resistance. Same thing happens in the tunnel. The only difference is that you're stationary in relation to the planet, but your body doesn't know that (and neither does the planet [;-)]). So, it doesn't matter if you're falling through the air at 250km/h or your being held in the air at 250 km/h, it's just in one case you're moving through the stationary air whereas in the tunnel the air is moving past you. The only thing that's different is the view and the fact you have to do something in order not to smoke into the planet [;-)]

"Bodygolfing" isn't as much fun as it sounds. People get pissed when you don't replace your divets.

[jbrinkman 0]

Well, if you start being that anal (and incorrect) One force of gravity means that without resistance, you will accelerate at 9.81 m/s^2. If there is no resistance, you, personally, would feel zero g forces. G Forces are determined in relation to yourself. So even though you are accelerating, you feel 0 g. That is why satellites stay in orbit. They are constantly falling but keep missing the planet because they have sideways momentum and no resistance. If you decelerate (while moving Parallel to the pull of gravity), you experience more G Forces, if you accelerate, you feel less.

Also, if we get nitpicky, When skydiving, the force of gravity is less the further you are away from the center of the earth. Also, as you get lower in the atmosphere, even though the force of gravity increases, so does the resistance to the increasing number of air molecules, so you are actually decelerating as you go down. This does not happen in a tunnel. So, pretty much imperceptably, you actually get more "blood rushing to your head" during a skydive than in the tunnel because you are constantly decelerating (after reaching terminal velocity, that is).

I hope that's being picky enough for you.
9-iron out.