For those that hate the BNP .......

[Apache]

As one of the exalted people who actually understand aerodynamics, and have designed flying machines from first principles, the plane WILL fly. If you somehow manage to delude yourself that it wont, you are indeed truly stupid and should probably not be out alone in public, and should probably use only plastic cutlery from now on.

Yes, Dieselboy, we appreciate you are trolling, and this is much more interesting than hating the BNP.

[Maverick]

I've probably never understood the question on this one (I'm ready to be shouted at).

If the plane is on a conveyor and that conveyor is travelling at the same speed backwards than the planes thrust is able to propell it forwards, then surely the plane is effectively stationary. If the plane is stationary then how is the wind moving over it's wings to produce lift?

I know on Mythbusters the plane took off, but the conveyor was moving slower than the plane, so the plane gained forward momentum, thus gaining wind speed and lift.

[dieselboy]

As one of the exalted people who actually understand aerodynamics, and have designed flying machines from first principles, the plane WILL fly. If you somehow manage to delude yourself that it wont, you are indeed truly stupid and should probably not be out alone in public, and should probably use only plastic cutlery from now on.

Yes, Dieselboy, we appreciate you are trolling, and this is much more interesting than hating the BNP.

aerodynamics do not come into play here whatsoever

at what speed does a 737 need to achieve before it can take off? book says 150mph. the plane does not even reach 1mph so lift is not even thought upon.

[lord lucan]

I've probably never understood the question on this one (I'm ready to be shouted at).

If the plane is on a conveyor and that conveyor is travelling at the same speed backwards than the planes thrust is able to propell it forwards, then surely the plane is effectively stationary. If the plane is stationary then how is the wind moving over it's wings to produce lift?

I know on Mythbusters the plane took off, but the conveyor was moving slower than the plane, so the plane gained forward momentum, thus gaining wind speed and lift.

the plane is always going to gain forward momentum its just that being on a convayor belt the wheels are gonna spin faster, i cant believe that anyone would think any otherwise

[Maverick]

the plane is always going to gain forward momentum its just that being on a convayor belt the wheels are gonna spin faster, i cant believe that anyone would think any otherwise

If the conveyor belt is traveling backwards at the same speed to match the forward thrust, then how is the plane going to gain forward momentum?
Are not the forces equalising out?

You can call me thick if you want (qualifications would dispute that), but explain your workings.

[lord lucan]

If the conveyor belt is traveling backwards at the same speed to match the forward thrust, then how is the plane going to gain forward momentum?
Are not the forces equalising out?

You can call me thick if you want (qualifications would dispute that), but explain your workings.

the wheels are free rolling, you might as well just have air in between the plane and the belt, just out of interest what qualifacations have you got as my accountant has loads but he asked me to change a plug because he didnt know how to?

[Maverick]

This is how I see it, I am willing to be proven wrong.

The planes engine (prop or rocket) produces forward force, now initially this is displaced through the contact with the ground surface (earth, water, concrete, whatever), until forward momentum creates enougth air speed to produce lift.

Now if that forward force was displaced onto an item (conveyor belt) that absorbed it (by being equal or greater), then it could not get the forward momentum, so no air speed, no lift.

Unless you're informing me that the engine can disturb enougth air around the plane get the wind up to take off speed and thus create lift (of course in the case of virtical take off and landing aircraft this is the case).

[MattF]

Now if that forward force was displaced onto an item (conveyor belt) that absorbed it (by being equal or greater), then it could not get the forward momentum, so no air speed, no lift.

You're working on the assumption there that the drive is being provided by the wheels. It isn't. The conveyor belt cannot displace, (practically), anything because the wheels are freely rotating. The motive force is created through the displacement of air.

[Maverick]

You're working on the assumption there that the drive is being provided by the wheels.

Actually I'm not. I'm working on the assumption that the prop is pushing the plane forwards, by clawing (for want of a better word) through the air. Due to gravity the plane will always start with some form of contact point with the earth, and this is the first thing it has to break.
Now if the Earth rotated backwards at the same speed as the prop clawed through the air forward, surely the plane would, in effect, be stationary.

Honestly I'm not argueing, I just (at the moment) can not see the flaw in my thinking.

[MattF]

Right then. Simple terms. Does a full bog roll rotate quicker than an almost empty bog roll when you pull three sheets?

[biosurf]

Right then. Simple terms. Does a full bog roll rotate quicker than an almost empty bog roll when you pull three sheets?

Don't know about you, but at that moment my attention is occupied with holding the book open on the floor with my foot. Couldn't tell you what speed the bog rolls doing

[BUSHWHACKER]

Wow, Apache has designed planes.
Then how come he's driving around in a shed of a truck?


It won't take off for the reason Maverick said, the plane will be stationary!

You can't believe Mythbusters' experiments as it's just an entertainment show.
Take for example the 'moon landing' Apparently man 'did' walk on the moon because they 'proved' it. Do you think they would say otherwise? on American TV?? thats overlooked by the US Government.


just going to finish my soup now, it's taking ages with this bluddie plastic fork.

Is this weedol I'm drinking?

[Maverick]

Right then. Simple terms. Does a full bog roll rotate quicker than an almost empty bog roll when you pull three sheets?

Yes, but I'm not pulling bog roll.

If I sit on a skateboard (I never managed the balance to stand) with a leaf blower pointed backwards and switched on will I move forwards?.....Yes.

Now if I move that skateboard onto a running machine and (with the leaf blower switched on) accelerate the running machine until it matches the speed of wind that the leaf blower is blowing will I move forward, or will I be stationary? The laws of physics as I understand them make me believe that I would effectively (to anyone who wasn't on the running machine with me) be stationary.


Now do you see why I'm not seeing your logic. It goes against the laws of physics as I have understood them.

[MattF]

Alright then. An alternative approach.........

[BUSHWHACKER]

Alright then. An alternative approach.........

The plane is landing now?!