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Enroute Airbus A380 wake flips Challenger business jet upside down

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Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#71

Post by wfunction »

M_Grey wrote: post #65
wfunction wrote: post #56

Earlier quoted context omitted.

While I agree with the general sentiment, to be honest there are easier solutions here. They could've just turned on the sign as soon as they saw the A380 so that people could fasten their seatbelts then. And then turned off the sign when the threat was gone. You don't need a cannon to kill a fly.

In the 1-2 minutes between this thing booming past them, and being sent into a spin... you want them telling people to buckle up? That doesn't seem like the easier solution; it mostly sounds like a way to have people still hurrying in the aisles when it's too late.

Even half a minute minute is a hell of a lot of time and overwhelmingly better than no notice. Currently airplanes sometimes only turn on the sign after the turbulence has already started.

Also, it's not like they never have no idea which airplanes are around them until they visually see the airplane. They could turn on the sign earlier if they know earlier.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#72

Post by fulafel »

M_Grey wrote: post #64
taejavu wrote: post #49

Earlier quoted context omitted.

Yeah I'm pretty sure that's the first rule that goes out the window when you're on a private jet.

There's a reason that people with money and power don't always experience good outcomes. Sure, you can do what you like on your jet, and therefore expose yourself to risk that most people never experience. Likewise skiing off-piste or a number of other equally silly activities that you can do, but absolutely shouldn't.

Probably they have a different idea about risk management than more risk-averse people. Worrying a lot about very low probability events is not compatible with the risk-taking typically required to make a lot of money. After all millionaires are largely a "survivor club" filtered from high risk appetite workaholics.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#73

Post by jmts »

This is quite interesting. I've been living underneath a flight plan for the last few years, and every now and then I've noticed a strange noise that seems to come from the air a few seconds after a plane has passed overhead on approach. The best way I can describe it is as a tearing noise, somewhat like a long stretched version of a tear in paper, or fabric. I've long suspected that it may be due to turbulence, and this article certainly suggests that the turbulence for some aircraft is much more powerful than I'd suspected.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#74

Post by JumpCrisscross »

taejavu wrote: post #49
lutorm wrote: post #44

This is a reminder that the announcement that you should "keep your seat belt fastened at all times when you're in your seat" isn't just something someone made up. It's a small price to pay in case you ever encounter severe turbulence en route, but it might be one of these things that most people don't realize until it happens to them. Hitting your head against the cabin ceiling can seriously put a damper on your tri…

Yeah I'm pretty sure that's the first rule that goes out the window when you're on a private jet.

Never in my experience.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#75

Post by xapata »

taejavu wrote: post #49
lutorm wrote: post #44

This is a reminder that the announcement that you should "keep your seat belt fastened at all times when you're in your seat" isn't just something someone made up. It's a small price to pay in case you ever encounter severe turbulence en route, but it might be one of these things that most people don't realize until it happens to them. Hitting your head against the cabin ceiling can seriously put a damper on your tri…

Yeah I'm pretty sure that's the first rule that goes out the window when you're on a private jet.

Private planes also crash far more often than standard airline flights.

Case in point: Chapecoense.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#76

Post by jeffdavis »

Zak wrote: post #39
cyberferret wrote: post #36

Earlier quoted context omitted.

If you recall Boyle's Law from high school physics - Temperature is proportional to pressure. Aircraft wings generate an intense area of low pressure over the top of the wing (which is what essentially generates the lift). This low pressure area is magnified when flaps and slats are deployed. On a humid day, the lowering of the pressure over the wings can basically force the air temperature at that point to lower and…

Wings generate lift primarily by deflecting air downward. There is an area of low pressure over the wing where air is taking a longer path than under the wing, but that is only responsible for a small fraction of the lift.

The only thing that can possibly lift a normal aircraft (i.e. not a rocket) is if the air is higher pressure on the bottom than the top.

Deflecting air downward is the way they create that pressure difference.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#77

Post by ajross »

Zak wrote: post #39
cyberferret wrote: post #36

Earlier quoted context omitted.

If you recall Boyle's Law from high school physics - Temperature is proportional to pressure. Aircraft wings generate an intense area of low pressure over the top of the wing (which is what essentially generates the lift). This low pressure area is magnified when flaps and slats are deployed. On a humid day, the lowering of the pressure over the wings can basically force the air temperature at that point to lower and…

Wings generate lift primarily by deflecting air downward. There is an area of low pressure over the wing where air is taking a longer path than under the wing, but that is only responsible for a small fraction of the lift.

That's a meaningless correction, and technically not correct. Aircraft are lifted up by air molecules hitting the underside of the rigid body with more force than the top side, by definition. The net integrated instantaneous pressure at the surface of the aircraft IS the lift.

The fact that air gets deflected downward is a necessary (c.f. conservation of momentum) effect too. So it's not incorrect to do the analysis that way. But it's absolutely wrong to correct someone saying that "lift is pressure" with "lift is actually deflected air".

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#80

Post by ajross »

nether wrote: post #41
Zak wrote: post #39

Earlier quoted context omitted.

Wings generate lift primarily by deflecting air downward. There is an area of low pressure over the wing where air is taking a longer path than under the wing, but that is only responsible for a small fraction of the lift.

"Longer path" has no bearing on reality. A flat plate can generate plenty of lift even with both sides the same. It's also hard to define "path," as the air starts convecting well ahead of the wing in subsonic flow.

Flat plates generate lift even in near vacuum conditions where the whole idea of Bernoulli flow is inapplicable, even.
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