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

[dieselboy]

Ok, we're all bored now!



Can we go back to talking about planes and conveyer belts or something?

It won't take off by the way!

thats right it wont take off, the runway is moving away from the plane and the plane is stationary.... or something..

[dieselboy]

i dont do telly
i surf the net in sted
http://vids.myspace.com/index.cfm?fu...oID=2024925509

just download what you want to watch using torrents. there really isnt any need for sky or cable TV. all you need is an internet connection, with a decent upload speed, and a high def TV with a nice surround system, you will have all the films and tv shows you could ever possibly want, just like sky or virgin.
the difference being that when you switch the computer on, you decide you can watch something interesting -
whereas if you had sky or cable, the tv decides you watch some pap that you have no interest in.

[JUDWAK]

http://www.veoh.com/
every channel on the planet has its own web site most have a player
veoh is ok for wildlife and stuff

[Albannach]

thats right it wont take off, the runway is moving away from the plane and the plane is stationary.... or something..

The conveyor belt is moving backwards, it will take off. Even if it was moving forwards, it would still take off. Think catapult on an Aircraft Carrier.

You have a RC plane, try it...

[dieselboy]

The conveyor belt is moving backwards, it will take off. Even if it was moving forwards, it would still take off. Think catapult on an Aircraft Carrier.

You have a RC plane, try it...

no, we found out that it wouldnt take off because in this imaginary scenario, the runway moved backwards with as much force as the jet engines provided to overcome the friction of the wheels and the weight of the plane to move forward. therefore the thrust and drag factors eaqualled and the plane remained stationary with the stationary ground. because of this, there was no air moving accross the wings to provide lift to enable the plane to take off.

we also agreed that this would never happen in real life.

[Albannach]

no, we found out that it wouldnt take off because in this imaginary scenario, the runway moved backwards with as much force as the jet engines provided to overcome the friction of the wheels and the weight of the plane to move forward. therefore the thrust and drag factors eaqualled and the plane remained stationary with the stationary ground. because of this, there was no air moving accross the wings to provide lift to enable the plane to take off.

we also agreed that this would never happen in real life.

We agreed no such thing.

[yoshie]

no, we found out that it wouldnt take off because in this imaginary scenario, the runway moved backwards with as much force as the jet engines provided to overcome the friction of the wheels and the weight of the plane to move forward. therefore the thrust and drag factors eaqualled and the plane remained stationary with the stationary ground. because of this, there was no air moving accross the wings to provide lift to enable the plane to take off.

we also agreed that this would never happen in real life.

The wheels don't provide drive. The belt has no bearing on anything.
Hang the same plane from a string, spin the wheels as fast as you like, hit the thrust plane flys off.

[dieselboy]

We agreed no such thing.

yes i did.

[dieselboy]

The wheels don't provide drive. The belt has no bearing on anything.
Hang the same plane from a string, spin the wheels as fast as you like, hit the thrust plane flys off.

if you hang the plane from a string the wheels wont touch the floor will they.
the wheels dont provide the forward movement, what makes you think that?
i have a great link for you: edu-link

[Dodge]

Not this lame old donkey again.

The wheels do not provide any motive force what so ever, all the thrust is provided by the engines pushing against the air behind the aircraft.

The lift for the aircraft is created by the air moving over the wing being thinner than the air under it, the denser air lifts the wing and therefore the plane itself. This is basic aerodynamics and is achieved by it moving forward through the air until it reaches the required airspeed so the aerodynamics of the wing come into effect, this forward movement is created by the engine(s) pushing it forward against the air not through the wheels. It doesn't matter if the aircraft is on wheels, skids, floats, a conveyor, grass, ice, water or whatever, given forward thrust it will take off.

How anyone can think that the wheels can have any bearing on whether it will take of is unbelievable. The wheels are free spinning, like a scooter or a skateboard not driven like a car or bicycle. All that the aircraft being on a conveyor means is that the wheels will spin faster for a given air speed, if you fit smaller wheels they will also spin faster, conversely if you fit larger wheels they will obviously spin slower, neither will have any effect on whether the aircraft will take off.

If you still can't see it imagine this . . .

You have a hang-glider strapped to your back, this will create enough lift for you to take off when you reach an air speed of 10mph. You sit on a bicycle with no chain so a friend pushes you until after about 100 yards you reach 10mph and you take off.

Then you do it again but standing on a scooter, your friend pushes you again, after 100 yards your friend running at the same speed as before, you reach an air speed of 10mph and take off.

The only difference is the wheels on the scooter were spinning faster than the wheels on the bicycle.

If you still can't grasp the basics, imagine the scooter was on a conveyor, the conveyor is rolling backwards but you are held stationary by your friend, the wheels would be spinning already, but your friend wasn't on the conveyor he was on the road next to it, he would still run at the same speed, still take 100 yards to reach 10mph and you would still take off but the wheels would be spinning even faster.

Come on guys, it's not rocket science.

[yoshie]

The wheels don't provide drive. The belt has no bearing on anything.
Hang the same plane from a string, spin the wheels as fast as you like, hit the thrust plane flys off.

if you hang the plane from a string the wheels wont touch the floor will they.
the wheels dont provide the forward movement, what makes you think that?
i have a great link for you: edu-link

If you think the wheels provide drive, then I give up, life is to short.

[Slugger]

Not this lame old donkey again.


The lift for the aircraft is created by the air moving over the wing being thinner than the air under it, the denser air lifts the wing and therefore the plane itself. This is basic aerodynamics and is achieved by it moving forward through the air until it reaches the required airspeed so the aerodynamics of the wing come into effect, this forward movement is created by the engine(s) pushing it forward against the air not through the wheels. It doesn't matter if the aircraft is on wheels, skids, floats, a conveyor, grass, ice, water or whatever, given forward thrust it will take off.

Come on guys, it's not rocket science.

Harrier jump jet is another example , side thrusters vertical and the plane lifts off the ground , no wheels have moved ,whilst hovering rotate side thrusters to the horizontal position and plane moves forward - still no wheels have turned.

[dieselboy]

Not this lame old donkey again.

The wheels do not provide any motive force what so ever, all the thrust is provided by the engines pushing against the air behind the aircraft.

The lift for the aircraft is created by the air moving over the wing being thinner than the air under it, the denser air lifts the wing and therefore the plane itself. This is basic aerodynamics and is achieved by it moving forward through the air until it reaches the required airspeed so the aerodynamics of the wing come into effect, this forward movement is created by the engine(s) pushing it forward against the air not through the wheels. It doesn't matter if the aircraft is on wheels, skids, floats, a conveyor, grass, ice, water or whatever, given forward thrust it will take off.

How anyone can think that the wheels can have any bearing on whether it will take of is unbelievable. The wheels are free spinning, like a scooter or a skateboard not driven like a car or bicycle. All that the aircraft being on a conveyor means is that the wheels will spin faster for a given air speed, if you fit smaller wheels they will also spin faster, conversely if you fit larger wheels they will obviously spin slower, neither will have any effect on whether the aircraft will take off.

If you still can't see it imagine this . . .

You have a hang-glider strapped to your back, this will create enough lift for you to take off when you reach an air speed of 10mph. You sit on a bicycle with no chain so a friend pushes you until after about 100 yards you reach 10mph and you take off.

Then you do it again but standing on a scooter, your friend pushes you again, after 100 yards your friend running at the same speed as before, you reach an air speed of 10mph and take off.

The only difference is the wheels on the scooter were spinning faster than the wheels on the bicycle.

If you still can't grasp the basics, imagine the scooter was on a conveyor, the conveyor is rolling backwards but you are held stationary by your friend, the wheels would be spinning already, but your friend wasn't on the conveyor he was on the road next to it, he would still run at the same speed, still take 100 yards to reach 10mph and you would still take off but the wheels would be spinning even faster.

Come on guys, it's not rocket science.

i will try to be as explanatory as possible without sounding like a ####, so dont take this the wrong way but please do a little research on physics and then reply back, more specifically a thing called drag - i dont mean men dressing up as women!

briefly, i refer to newtons law: To every action there is an equal and opposite reaction. to explain this, this means that for everything that happens there is an equal force. for example, you have a table in front of you that is holding its own weight. the legs are providing as much upwards force as the table is providing downwards therefore the table remains stationary. if a 20 stone man decides to sit on the table (successfully) then the table is now providing an upwards force of 20 stone plus the weight of the table. the change here is that the table is now providing, in addition to its own force in weight, an upwards force of 20 stone. if the table did not provide this additional force then the table would collapse under the extra weight.
likewise, when the 20 stone man got off the table, if the table didnt stop providing the upwards force then the table would lift off the ground.

you mention a bicycle and hang glider but no chain... the forward force here is someone pushing you forward.. there is a forward force that has overcome the opposite forces enough to gain a speed of 10mph.

here is a much lower scale example that i have made up that can be used as a reference point:
next time you are at the airport (gatwick will do) get your suitcase with wheels on and have someone walk it on the travellator whilst you walk around the travellator on the stationary ground. next reach over the side and try to move the suitcase in the opposite direction to the direction of the travellator. you will find it a lot harder than if you and the suitcase were either on the stationary ground or both on the travellator.
the reason for this is simple. the travelator is acting on the suitcase, therefore trying to move it in a direction. if the travellator did not transfer the kinetic force to the suitcase then the suitcase would remain stationary with the ground and the travellator would continue move in the same direction.

going back to talking about the airoplane on the conveyor, the same principle applies here. the difference is that the conveyor is providing the same force one way as the jets are providing the other way. the two forces are equal and therefore the plane stays stationary with the stationary ground beside the conveyor.
you are confusing my reasoning with an assumption that i am somehow trying to put accross that it is the wheels that provide the driving force. this is incorrect. the wheels, the weight of the plane etc will provide drag. this drag is taken up by the conveyor and turns this into kinetic energy - a force.

for the plane to take off, the jet engines will have to match this force just to remain stationary plus additional force to gain speed and take off.
however, in this situation the conveyor provides as much force one way as the jets provide in the opposite direction and therefore the plane does not take off it remains stationary.

[MattF]

the wheels, the weight of the plane etc will provide drag. this drag is taken up by the conveyor and turns this into kinetic energy - a force.

None of which will ever equal forward thrust. Stop trolling.

[dieselboy]

Haha