How on earth does this work?

[schmalex]

http://www.youtube.com/watch?v=uw2qPLEgKdQ

Doing a complete roll in a commercial airliner, whilst pouring a glass of iced tea without spilling a drop

[southendpier]

Centrifugal forces. Remember that the plane is shifting height (downwards) although you can't tell from the picture and creating it's own gravity. Sort of.

[hifihigh]

As long as the force accelerating the fluid into the glass is greater than gravity then that should work.

[dr_gn]

southendpier said:

Centrifugal forces. Remember that the plane is shifting height (downwards) although you can't tell from the picture and creating it's own gravity. Sort of.

It'll only work with a barrel roll. The aircraft isn't necessarily losing height, rather it's describing a helical path through the air.

[Arese]

I can't see the video at work. Is there a conveyor belt involved?

[Eric Mc]

A perfectly executed barrel roll will generate enough G to prevent liquids from spilling out of a beaker or tumbler - as demonstrated by Bob Hoover many years ago in his Commander 580.

[Simpo Two]

Eric Mc said:

A perfectly executed barrel roll will generate enough G to prevent liquids from spilling out of a beaker or tumbler - as demonstrated by Bob Hoover many years ago in his Commander 580.

And Alex Henshaw in a Lancaster

In reverse, it's also the way that a pilot in cloud who gets disoriented can spiral straight into the ground whilst being sure he's flying straight and level.

Edited by Simpo Two on Tuesday 5th October 13:27

[Engineer1]

dr_gn said:

southendpier said:

Centrifugal forces. Remember that the plane is shifting height (downwards) although you can't tell from the picture and creating it's own gravity. Sort of.

It'll only work with a barrel roll. The aircraft isn't necessarily losing height, rather it's describing a helical path through the air.

Just out of interest how does a force that pulls to the center of the circle stop the liquid coming out? also if centrifugal force exists how do walls of death work and how do you spin a weight on a string?
Ok I am being a pedant, it is centripetal force, ie. the one that pushes out, that is responsible, think about it spinning a weight on a string if the string breaks the weight flies off at a tangent.

[KrazyIvan]

I think the plane stayed still and the earth rolled round it, that or some sort of devil worship

[ewenm]

Engineer1 said:

dr_gn said:

southendpier said:

Centrifugal forces. Remember that the plane is shifting height (downwards) although you can't tell from the picture and creating it's own gravity. Sort of.

It'll only work with a barrel roll. The aircraft isn't necessarily losing height, rather it's describing a helical path through the air.

Just out of interest how does a force that pulls to the center of the circle stop the liquid coming out? also if centrifugal force exists how do walls of death work and how do you spin a weight on a string?
Ok I am being a pedant, it is centripetal force, ie. the one that pushes out, that is responsible, think about it spinning a weight on a string if the string breaks the weight flies off at a tangent.

So the force must be pulling IN to keep the weight from flying off. Centripetal forces act towards the centre of the rotation to maintain the curved path. There is no outward force.

The inertia of the liquid keeps it in the container which is why it needs to be a fast enough rotation - too slow and gravity overcomes the inertia.

Edited by ewenm on Tuesday 5th October 13:34

[dr_gn]

Engineer1 said:

dr_gn said:

southendpier said:

Centrifugal forces. Remember that the plane is shifting height (downwards) although you can't tell from the picture and creating it's own gravity. Sort of.

It'll only work with a barrel roll. The aircraft isn't necessarily losing height, rather it's describing a helical path through the air.

Just out of interest how does a force that pulls to the center of the circle stop the liquid coming out? also if centrifugal force exists how do walls of death work and how do you spin a weight on a string?
Ok I am being a pedant, it is centripetal force, ie. the one that pushes out, that is responsible, think about it spinning a weight on a string if the string breaks the weight flies off at a tangent.

I never mentioned centrifugal or centripetal forces

[dr_gn]

Eric Mc said:

A perfectly executed barrel roll will generate enough G to prevent liquids from spilling out of a beaker or tumbler - as demonstrated by Bob Hoover many years ago in his Commander 580.

Doesn't have to be perfectly exectuted, just has to generate enough G to keep the fluid/glass from falling during the manouver.

ETA, that was what the video was (Hoover).

Edited by dr_gn on Tuesday 5th October 13:40

[Eric Mc]

I couldn't download it for some reason so I kind of assumed it might be the Hoover footage.
Still impressive after all these years.

[Flintstone]

schmalex said:

Doing a complete roll in a commercial airliner...

No airliner but still a classic clip.

[Tango13]

I remember reading some where that the trick was to barrel roll a Vulcan without the three in the back noticing...

[VvrooomM]

I can see how it stays in the glass but surely by the same logic it should stay in the jug and he shouldnt be able to poor it??? Thats the bit that doesnt make sense to me!!

[Silent1]

VvrooomM said:

I can see how it stays in the glass but surely by the same logic it should stay in the jug and he shouldnt be able to poor it??? Thats the bit that doesnt make sense to me!!

Physic fail

[Eric Mc]

VvrooomM said:

I can see how it stays in the glass but surely by the same logic it should stay in the jug and he shouldnt be able to poor it??? Thats the bit that doesnt make sense to me!!

Depending on the rate of role - the G loading can be adjusted. If the roll rate produces only (say) 1/2 a G, then liquid will pour from the glass. If the roll equals 1g or more, the liquid will stay in the glass.

[Simpo Two]

It's more than the 'roll'; if you just did a straight roll you'd get lateral G and the grass would fly sideways. What you need to do is keep positive G vertically down to the cockpit floor, that's all. Doesn't matter what the 'plane is doing relative to anything else.

0.5G, 1G, 2G, it doesn't matter as long as it's straight down the axis of the glass.

[dr_gn]

Silent1 said:

VvrooomM said:

I can see how it stays in the glass but surely by the same logic it should stay in the jug and he shouldnt be able to poor it??? Thats the bit that doesnt make sense to me!!

Physic fail

And English.