Korean Job Discussion Forums

[chest rockwell]

Will the plane be able to take off? ...
Not so much a picture post, but you guys should have some fun.


Heres the scenario...

An airplane is on a conveyor. The conveyor is set to match the speed of the airplane in the backwords direction. However fast the plane moves, the conveyor moves just as fast.

Can the plane take off?

[Swiss James]

nah, I think the plane needs to have the force of the air moving over the winds at whatever the takeoff speed is to generate the lift. If it's got no momentum, there's no lift.

Plane stays put.

[antoniothegreat]

if a baseball game is played in the woods, and no one keeps stats, does it count in the standings???

[Wangja]

What makes a plane fly is not speed over the ground but speed through the air.

Now if the plane were in a fixed horizontal position on the conveyor, but facing a wind machine, if the wind velocity were high enough the plane would rise.

(I guess the wind speed needs to be approximately 100 kph for a small propellor plane and 220 kph for a large jet).

[deessell]

Are you watching Myth Busters on the Discovery Channel???

[SPINOZA]

I don't think the plane would take off personally. In this case, relatively speaking, the plane's speed is 0mph and one assumes a plane cannot take off in this condition.

[Wangja]

OK, let's make it simpler.

The wings need to move through the air.

[Swiss James]

the air's going nowhere on that conveyor belt- so I guess we're all agreed. No flight today.

[igotthisguitar]

Hmmmm ... my guess is upon reaching take off speed it would rise vertically & violently shoot forward.

[Swiss James]

[HapKi]

I'd say no., because there is no air stream under the wings.
Here's another one.

A plane takes off with a load of birds in cages. Lets say about a ton worth of birds.
During the flight, the cages burst open and the birds start flying around in the cargo. Is the plane still carrying that ton of weight?

[Wangja]

Dear God,

Your uneven spreading of the grey matter is proof positive of your sense of humour and never fails to cause me so much joy.

Yours sincerely

wangja

[mithridates]

No, it's not carrying the weight anymore. The birds though are actually flying at aroung 900 kph relative to the land.

In the same vein, couldn't people do something weird to the plane's direction by all jumping and landing at the same time? A slight push down when they jump, then about half a second with suddenly no passenger weight, and then they all come crashing down.

Actually this reminds me of something I used to think about when I worked in offices. Riding the elevator is fun but it could be more fun, and here's how. Pay attention:

My method for more fun in the elevator (besides the obvious)

Going up: Passenger A is going to floor 35. The elevator starts going up, but at a phenomenal rate, until passenger A has enough upward velocity to reach 35 even if the elevator were to suddenly disappear. At this point the elevator gives a sudden lurch for just a millisecond, enough to propel passenger A into the air. He's now cruising upward on his own momentum and the elevator is following at the exact same speed, so from his point of view he's floating in the elevator. As he starts to slow down from gravity so does the elevator, and they both eventually settle nicely in at floor 35.

On the way down the same thing, except the elevator starts by going down at free-fall speed, but with a slight lurch downward so it's always a little bit ahead of passenger A. This persists until just before the point of no return (maybe about a third of the way down) where the elevator has to slow down, and passenger A is standing on the bottom of the elevator again.

That would be awesome.

[Ya-ta Boy]

[Pligganease]