Skill's weekend teaser

[Skill Leverage]

Set him right please Sir Gecko

 

[TheBramble]

OK Skill. I'm not trying to further underline your lack of knowledge, I'm simply trying to help you.

A plane generates lift by sticking largish amount of air past its wings.

It normally attempts this by building up a bit of speed in the forward direction via the thrust from its engines and with a bit of luck, takes off.

Now, it's quite possible you could line a 747 up pretty much anywhwere and blow a 180mph gale over it and with a bit of bumping and swaying, it'll hover for a bit, but it's not the suggested takeoff method as laid down in the manual.

However, on your conveyor, the plane has (by your definition) NO FORWARD MOTION. It therefore has insufficient airflow to generate the necessary lift.

It's as simple as that.

KIssy Kissy.

 

[TheBramble]

Lol @ nice little boy - come along next Friday mate, we'll see who's the little 'un

Steady on old son or I might.

 

[Skill Leverage]

It has no forward motion until the engines are switched on, then it takes off normally. You cannot understand that the conveyor belt makes ABSOLUTELY NO DIFFERENCE TO ITS FORWARD MOTION, because you are of lesser intelligence than I.

Kissy kissy.

 

[Skill Leverage]

Steady on old son or I might.

Please, please, please do.

 

[Skill Leverage]

Let me break it down for you Bramble, I'll hold your hand like a small child:

Imagine a frictionless Swiss Ball on a treadmill. No matter how fast the treadmill goes, the ball will just roll away, rotating at the same speed as the treadmill, yes?

 

[Skill Leverage]

Now, what happens if you were to blow very hard on the ball? Would it move forward? Yes, it would!

See if you can relate that to the problem at hand. Zupcon, Aspire, Arabian and a few others have managed to figure it out. There may not be a prize for eighth place, but I'm sure we can arrange a lolly or something.

 

[Skill Leverage]

Oh, and Hotch too, straight away boom got it. He has a brain. I'm hoping one of them will come and explain their thinking to you..

 

[Hotch]

I'm not the best person to answer this, I might ask someone far more intelligent then me to have a whack at an explanation but...

I think I see where bramble is coming from:

plane takes off <=lift generated<=air going under wings<=plane must be moving forward.



I think the fault in the logic is the last part. Don't the jets suck air in and out, thus moving the air about it? I did wonder if jets only speed up air movement, but then of course, how would a plane start moving in the first place anyway?

This might all of course be wrong, in which case i relinquish all claims of having afore mentioned brain.

P.S. I think the question could of been worded better Skill

 

[Skill Leverage]

In case you haven't managed it; the plane's wheels are like two Swiss balls on a treadmill - they have NO EFFECT ON THE FORWARD MOTION OF THE PLANE, because there is no drive shaft connected to the wheels.

The ball being blown on is similar to the effect of switching on the engines - an external force is applied to a stationary body, THUS the plane takes off, and it doesn't give two hoots whether it's on a conveyor belt, tarmac, the sea, lava, a massive swiss ball or a puddle of urine.

 

[new_trader]

Just Pull The Trigger!

I mean

The Plane takes off normally...

An aircraft only cares about air speed, not ground speed.

 

[Skill Leverage]

The question is worded pretty much straight out of a book. People like Bramble fail to realise that this isn't something I've just cooked up, it's been postulated the world over; as I mentioned some of the top minds in the world have proved this conclusion, and there's a bleeding video of it happening on YouTube (although video evidence isn't enough for him apparently).

 

[MrGecko]

However, on your conveyor, the plane has (by your definition) NO FORWARD MOTION. It therefore has insufficient airflow to generate the necessary lift.

When the plane starts its engines, it moves the plane forward through the air. The speed of the plane relative to the conveyor belt is irrelevant, it is the speed of the plane with respect to the air that, through the wings, generates lift.

 

[Skill Leverage]

Just Pull The Trigger!

I mean

The Plane takes off normally...

An aircraft only cares about air speed, not ground speed.

When the plane starts its engines, it moves the plane forward through the air. The speed of the plane relative to the conveyor belt is irrelevant, it is the speed of the plane with respect to the air that, through the wings, generates lift.

Yay, I might not get banned after all! Bloody Muscletalkers, couldn't get a single one of them to understand

 

[Bloodhound]

Maybe I've got the wrong end of the stick but, in order for a plane (or any aerofoil for that matter) to fly, air must flow across the aerofoil - in this the case the wings of the plane. This airflow hits the leading edge of the wing and is divided into faster air, which runs over the top of the wing and slower (more turbulent) air, which runs under the wing. The difference in speed between these 2 airflows is what creates lift and, in turn, this lift allows the plane to fly. If I have understood the question correctly, the conveyor belt is being used to reproduce forward motion which equates to airflow passing over the wings, which equals lift. The simplest example of this can be found by flying a kite. On a low wind day when there is insufficient wind to produce enough lift one would run into the wind to create enough wind (apparent wind) to generate lift to enable the kite to fly.
Hope I'm somewhere near where you're coming from Skill??

 

[TheBramble]

When the plane starts its engines, it moves the plane forward through the air.

But Skill tells us the plane isn't moving forward as the exactly matching (but opposite) movement of the conveyor effectively cancels out any forward movement of the plane.

The speed of the plane relative to the conveyor belt is irrelevant, it is the speed of the plane with respect to the air that, through the wings, generates lift.

The speed of the plane relative to the coveyor is irrelevant, yes. And yes it is relevant with respect to air speed. But if the plane isn't moving through the air...there is no airspeed.

 

[Skill Leverage]

I said THE WHEELS exactly match the speed of the belt. Not the plane. That's what you don't understand.

 

[Skill Leverage]

Are a plane's wheels moving when it's in flight Bramble? No, they're not. So why are you relating the speed of the wheels to whether the plane is moving forward or not?

The only thing that causes a plane to go forward is the THRUST from the ENGINES.

 

[TheBramble]

I said THE WHEELS exactly match the speed of the belt. Not the plane. That's what you don't understand.

If the wheels exactly match the speed of the belt what is the plane's airspeed and the belt's speed and the plane's groundspeed relative to the ground under the conveyor when the conveyor has a nominal speed of 180mph?

 

[Claudia123]

I said THE WHEELS exactly match the speed of the belt. Not the plane. That's what you don't understand.

Don't ya wish you never started this thread and gone to pub instead. Very funny to read though - thanks. I too dumb to work it out so I leave you guys to argue!!