... could be a 526 mts. deep Siberian diamond mine.


Warning: That picture is safe, but the rest of the website seems loaded with spyware.

Getting used in a future SR game. I swear it.

Aye, it's a nice picture to use as a prop for the group to see. Hmmm...

wow... good find. reminds me of a thermal borehole from Alpha Centauri.

AWSOM!

Torzx

Apparently, winds are so strong that helicopters are sucked in.

[Neo]Whoa.[/Neo]

I shake in my boots at the thought of going in there already.

I'm not sure that I buy that. The further you go down a hole, the higher the air pressure, because of the weight of all the air on top of it. If the bottom of the pit is colder, the air would be a little denser still, but stable, with nothing to move it around, and no where to go.

Now if you go deep enough, you have geothermal effects, and the air at the bottom of the shaft would want to rise. Then you'd get currents in and out of the place, as warmer air rose out and more air would move in to replace it. I don't know how strong that would be.

In addition, any wing, including the rotary wing of a helicopter, works on the principle of every action having an equal and opposite reaction. Rotor puts pressure on air, therefore air puts pressure on rotor, creating lift. It doesn't matter how far the air goes or what it hits afterwards. Ground effect is an exception, because air pressure builds up underneath the wing. Helicopters can't fly at high altitudes because of the thin air, but I don't see why the air just above the hole would be any thinner than the surrounding countryside. In other words, the surrounding air pressure is what determines an aircraft's performance, and that has little to do with the aircraft's altitude above ground level.

The only thing that I can't visualize is the effect of changes in weather. If a high-pressure system moves in, you'd get wind into the hole. A low pressure system, and wind out. Don't know how strong they'd be, but probably not very.

Lastly, if you have winds strong enough to suck a helicopter in, you'd have a damn hard time moving anything else in or out.

Anyway, as a pilot, I'd probably not take the chance until I've actually seen the place.

Well, what I saw in the quotes looked like two arguments. In one, the guy seemed to have the impression that air pressure above the hole would be different than the area around it. I don't see any reason to think that. Secondly, the idea was presented that there would be constant movement of air into the hole. This I see potentially happening, but I don't think the argument made for it is sound. It looks to me like the guy's just suggesting that air will move into the hole because it's a hole.

Your responses to my statements are valid, but I don't see what they have to do with the debate at hand. Of course they're simplistic; I didn't see any need to point out that wings lift up, or to get nit-picky about how ground effect works. (Assumption on my part; I thought the explanation was enough for the point I was making.) Maybe I can clarify where I was going with it: Just because ground effect indicates that being closer to the ground creates more lift, doesn't prove that the opposite is true. So if I'm cruising along at 200' AGL, then the ground drops out beneath me as I pass over a giant ant nest, and suddenly I'm at 1200' AGL or 12000' AGL. I haven't lost any lift, so long as the air pressure hasn't changed. I don't think it would change much, because my altitude ASL hasn't changed.

You're right that the aircraft will move relative to the ground if the air is moving. Obviously, if there's a wind, it'll push the aircraft around some. But then you'd still have to convince me that there's a lot of air moving into or out of the hole with more speed that a pilot can compensate for. That'd have to be some bitchin' thermals. Like I said, I doubt it, but I wouldn't bet my life on it.

Never flown anything other than a Cessna 172 and a couple of gliders. Physics seems the same to me. You?
(P.S. Why? Do you think the alleged giant hole air currents would affect one type of aircraft and not another?)

Anyway, don't mean to argue, Kagetenshi. Maybe I didn't explain myself thoroughly enough for someone who knows their flying. Do you agree with the reasoning behind JongWK's sources? I'd like to know your take on whether or not a passing helicopter would be sucked into the giant bug hole.

I'm just argumentative tonight, comes from sources unrelated to Dumpshock. It'll pass. I don't think I meant to imply that you thought your explanations were complete, but things needed to be clarified for the audience.

More when I'm awake, hopefully.

~J the brain-dead

You and I both, I suppose. No worries, bud.

Looks more like the entrance to Hell if you ask me.

I have no flying background of any kind, so this is pretty much spouting off in ignorance, but several of you have mentioned the difference that ground effects make in the lift that the helicopter can get. If a chopper was flying low enough for ground effects to provide extra lift, and then the ground effects were suddenly taken away (by taking away the ground...) I'd imagine that could make it tougher to control, and you'd have a greater likelihood of failling into the hole. Is this reasonable?

That's definitely reasonable, but as far as I can tell ground effect is mostly meaningful for helicopters when you're half the rotor diameter or less above the ground—not typical operating conditions, certainly.

Edit: "Ground effect typically does not exist when a plane operates more than one wingspan above the surface." (source)

~J

Yeah, you gotta be really low. Ground effect gives you some added lift, is the jist of it.

(I was taught a technique for using ground effect on rough field take offs. Say you want to save some wear and tear on your gear. You gun the throttle and cruise down the runway, then pop the plane up just a few feet at just the right speed. You're cruising above the crappy runway in ground effect, but you still have to accellerate some before you're fast enough to slip the surly bonds of earth, as it were.)

So, if you're cruising a few feet over the ground at low speed, and the ground drops out from under you, then yeah, you'd likely fall.

Ummm, helicopters don't push air down to fly.

The rotors are small wings, and create a low-pressure area over the helicopter, which lifts the helicopter. A hole like that would create a downdraft, which reduces the lift the rotors can generate. If there's that much of a change in pressure, then it will likely cause wind shear, which will frag with fixed-wing aircraft as they fly over the edges.

Ground effect does not affect helicopters as much as fixed-wings, and ground effect craft have specially designed "wings" and won't fly very high.

Just thought I'd share some...

I stand corrected... And I learned that in my solo classes from Air Force pilots...

Not that I didn't believe you but I looked and found this:

Helicopters fly by sucking air from above and forcing it downwards with a thrust equal to (for hovering) or exceeding (for climbing) the weight of the helicopter.