Is there some famous thread from before my time? I think it might be a good read. Can anyone link to it?
Bike Forum
What is this aircraft on a conveyor belt that people often quote?
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Posted 7 months ago #
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have only heard about this?am wondering what it is about also
Posted 7 months ago # -
Good god Nooooooooooooooooooooooooooooooooooo!
Posted 7 months ago # -
It's the old debate about whether an aircraft on a treadmill would be able to take off, IIRC. No idea whether that's from a thread or not.
Posted 7 months ago # -
I heard it's the only way that South African aircraft can avoiding hitting antelope when they take off.
The argument happens because some idiots think the aeroplane will take off even if the conveyor belt is running at the same speed as the aeroplanes wheels!!! I guess some folk just don't understand physics
Posted 7 months ago # -
Need to watch Mythbusters.
Posted 7 months ago # -
There have been many threads about it over the years, as Pyro said it's just that debate.
To nip it in the bud... Yes it can, as the engines provide the thrust not the wheels, but the treadmill would have to be as long as a normal runway. People think of it as gaining pace on the spot and being able to take off in no space, which is bollocks, the airspeed at take off would be identical, the wheels would just be going rather faster.
Posted 7 months ago # -
It's a bit like the P, only you didn't pay for the privilege to be a pre-hacked member
Posted 7 months ago # -
and we're off...
Posted 7 months ago # -
Mythbusters covered this a while ago.
Posted 7 months ago # -
See - I told you. There's always some idiot (njee in this case) that just doesn't get it at all.
Posted 7 months ago # -
allthepies - Member
Not if we're on a treadmill
and we're off...Posted 7 months ago # -
and so it begins......
Posted 7 months ago # -
lol at druidh
Posted 7 months ago # -
Posted 7 months ago # -
But surely it's the speed (pressure/lift) of the air flowing under and over the wings that give lift to make a plane take off?
A better question would be: can you blow air at a stationary plane and make it lift off the ground? Let's ignore for a moment how you would do that.
Posted 7 months ago # -
Yes, it's called a wind tunnel.
Posted 7 months ago # -
karinofnine - how would there be any air flowing under the wings of the treadmill was running at the same speed as the wheels? There wouldn't be any forward motion to generate lift.
And your second example is commonly known as "A Kite" (google it).
Posted 7 months ago # -
I am 100% with DruidH. Air speed across the wings is all that matters. If the conveyor constantly matches matches the acceleration of the aircraft then the air over the wings is static and the thing will never take off.
Unless the rotation of the wheels generates lift?
Posted 7 months ago # -
Exactly, the plane has to travel forward through air - I was disregarding the treadmill entirely.
We used to go to RAF Coltishall and watch the Lightnings take off. Fantastic.
Oh, they didn't use a treadmill either
Posted 7 months ago # -
Surely everyone knows this by now?
(And you always choose the other door, as it's more likely you'll win a car.)
Posted 7 months ago # -
No, but the wheels aren't powered, so the speed of the wheels is 100% irrelevant!
Can you push a bike along a conveyor belt?
That's what the engines are doing - pushing the plane forward. If the conveyor matched the speed of the plane, at takeoff the airspeed would be 150mph, whilst the wheels would be doing 300mph. It'd still take off just fine!
A car however, or a bike you were trying to cycle, would not move.
Posted 7 months ago # -
druidh.. stop it, you are being naughty!!!
Next you'll be telling me not to swap doors when offered the chance too!!
Edit: mike... snap!!
Posted 7 months ago # -
I think Njee is playing games.
Posted 7 months ago # -
I got another one....
If I am playing table tennis with a mate ( I do have one...)
on a flat bed truck
and it turns a corner just as I hit the ball...
which side of the table does the ball go off?
Posted 7 months ago # -
njee20 - that's the way I picture this too.
Posted 7 months ago # -
eviljoe - Member
I got another one....
If I am playing table tennis with a mate ( I do have one...)
on a flat bed truck
and it turns a corner just as I hit the ball...
which side of the table does the ball go off?
Top side. Fact.
Posted 7 months ago # -
A rocket, strapped to a skateboard on a supermarket checkout?
Posted 7 months ago # -
How about this one...
I'm running forward carrying a ball and I throw it behind me. Does the ball travel forward or back?
Posted 7 months ago # -
That's because you are right.
Posted 7 months ago # -
what was that old one about birds in a lorry?
Posted 7 months ago # -
Antelope
On a bicycle
In a wind tunnel
will it make any difference if the wheels are 26in or 29in?
Posted 7 months ago # -
This would need forward speed equal and opposite to the speed of the treadmill to remain stationary prior to attempting to take off.
Can it go forwards and vertically upwards at the same time?
If it was on the treadmill going 'forwards' (ie stationary but forwards relative to the treadmill) while the pilot went through the pre-flight checks and plane was readied for take-off would the act of switching from 'forward' to vertical movement sufficiently impeed the forward movement for it to fall off the back of the treadmill?
I suspect a plane capable of vertical take off may be the only kind not able to take off from a treadmill.Posted 7 months ago # -
Antelope
On a bicycle
In a wind tunnel
will it make any difference if the wheels are 26in or 29in?
Yes...
Now where was that video of the ostriches and the rally car?
Posted 7 months ago # -
You've missed out one crucial detail that the OP needs to know. There were at least TWO subtley different versions of the questions meaning that arguements could run and run...
1. the belt matches the aircrafts speed
2. the belts speed always matches the speed of the wheels.
Posted 7 months ago #
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