Krisboats Posted February 22, 2006 Report Share Posted February 22, 2006 Thats exactly it i reckon si. I think everyone else is under the impression that theres a delay with the conveyer matching the speed and the plane uses this delay to take off.ah i can sorta get it now, i think...the conveyer belt would only have an effect on the speed of the wheels...and theyre seperate, so theyll just spin faster than normal and the plane will move forwardsi get what they all mean now! its twigged, the wheels are spinning backwards. but youre still wrong. Link to comment Share on other sites More sharing options...
nb88 Posted February 22, 2006 Report Share Posted February 22, 2006 Nah its nothing to do with the delay.Just did a google search and found thisYou can test this with a piece of paper and a matchbox car (which has free rolling wheels like an airplane… or like a car in neutral.) Place the paper on a table, and place the matchbox car on the paper. Take your hand, and hold the car still with a lightly placed finger on top of the car. At this point you are providing no forward thrust, and the “conveyor belt” is not moving. The car remains stationary. Now, continuing to hold the airplane with a lightly placed finger, and start to pull the paper out from under the car, in the backwards direction. According to Neal’s logic, the car should push back on your finger with the same force that you are exerting on the paper… but this is not what will happen. You will find that your lightly placed finger is not stressed to any noticeable extent. The paper will slide out, and the wheels will spin, but the car will not be propelled backwards. The reason for this is is that the rotation of the wheels is not related to the movement of the matchbox car except by the very small friction component of the axle, which your lightly placed finger can easily control. Link to comment Share on other sites More sharing options...
ManxTrialSpaz Posted February 22, 2006 Report Share Posted February 22, 2006 Right, lets replace the plane with a car. If the car's wheels were moving at a potential 5mph and the conveyor belt was moving at 5 mph, the car would be effectively stationary. This is because the car's power is directed through the wheels into the conveyer but the conveyoer is directly cancelling out this movement by moving the opposite way. Now, an aircraft moves by directing it's power from the engines, into the surrounding air. Because the power doesn't go into the ground in any way, the plane will move and will take off.You'd have no problem accepting this if the plane wasn't touching the ground but really it's no different when it is touching the ground. What's happening below the engines does not affect the way the engines effect the plane.It's alot clearer in my head...... Link to comment Share on other sites More sharing options...
Krisboats Posted February 22, 2006 Report Share Posted February 22, 2006 "the wheels are spinning backwards" what the hell did i just mean? why would the spin backwards? oh my god i'm a fool.the plane can't take off. end of. the plane needs to roll on the wheels when it travels forwards, the wheels are on a conveyer belt that gives them the same forwards motion as if the plane wasnt on the ground at all. This means that the plane is going nowhere. The same as tying a fat chain around it and anchoring it into the ground. Link to comment Share on other sites More sharing options...
oakley Posted February 22, 2006 Report Share Posted February 22, 2006 I'm not "being stubborn and not opening my mind" but i don't get what your arguments are on about. If theres no friction on the wheels, then the plane is effectively floating isn't it? doesn't that make the conveyer belt irrelevant?But if the conveyer is running at the right speed to counteract the plane from going forwards, With all the planes weight being on the wheels it would mean that if they were being counteracted from spinning, then the plane wouldn't be able to go anywhere... The plane needs to roll first to take off so it can get its required air lift over the wings. But if its being stopped from rolling it won't have any lift so will not take off. I don't get what oli means by saying that the plane will just be able to have thrust and lift off... it needs to roll first but it's being stopped from rolling so if theres no forwards motion then the plane won't have any wind going over the wings so it can't just take off.If you could try explaining a bit more clearly then i would most likely get it, try using bullt points or something, it would help me out loads. i've sorta changed my mind, the plane wouldnt be able to start moving, even though it would be thrusting , because it needs friction on the floor to make it move, it USES its wheels to make it move, even though it isnt powered by the wheels. but they are moving. and the plane isn't. so the more thrust you put in to the plane, as it would start to roll the wheels would spin faster but the plane wouldn't move anywhere as the conveyor belt is matching the POWER!!!!think of a kid on a skateboard with rockets under his arms, on a conveyor belt. If the rockets proppel him to go at 30mph but the conveyor belt is going the other way at 30 mph he isnt in theory going newhere, but to him it feels like he is!!!! so he would be gettin no wind in his face = no wind over the wings of a plane/in the engines (whatever) equalling no movement.And the skateboard wheels, like the plane wheels have no engine moving them, it is all to do with the rockets/engines above!!!!i hope this is clear to you all!!joE! Link to comment Share on other sites More sharing options...
tipsy Jock Posted February 22, 2006 Author Report Share Posted February 22, 2006 Thats exactly it i reckon si. I think everyone else is under the impression that theres a delay with the conveyer matching the speed and the plane uses this delay to take off.i get what they all mean now! its twigged, the wheels are spinning backwards. but youre still wrong.Even if the change is instant it wont slow down the plane, as Oakley said a plane relies on thrust to get it moving and to create the wind resistance needed. Think of an airport trolley on a travelator, then tie a rope to the trolley and pull from one end of the travelator to the other. even if the travelator gets faster you will still be able to pull the trolley along and off the other end. although as a result of the travelator getting faster then wheels will be turning at least twice as fast as they would if the belt was turned off. Link to comment Share on other sites More sharing options...
Simon Posted February 22, 2006 Report Share Posted February 22, 2006 This conveyor has a control system that tracks the aircraft's speed and tunes the speed of the conveyor to be exactly the same, but in the opposite direction. Now, an aircraft moves by directing it's power from the engines, into the surrounding air. Because the power doesn't go into the ground in any way, the plane will move and will take off.It doesn't take off, it physically can't without the air around the wings at 200mph, and if the conveyor is also travelling at 200mph, whether the wheels be going at 200mph or the plane, it still means the plane isn't moving, and therefore can not take off. Link to comment Share on other sites More sharing options...
nb88 Posted February 22, 2006 Report Share Posted February 22, 2006 the plane can't take off. end of. yeah it can you sausage Link to comment Share on other sites More sharing options...
tipsy Jock Posted February 22, 2006 Author Report Share Posted February 22, 2006 Read this dimwits Answer Link to comment Share on other sites More sharing options...
anzo Posted February 22, 2006 Report Share Posted February 22, 2006 Anyone got a plane and huge conveyor belt with an RPM reader? I'm going to sort this once and for all... Link to comment Share on other sites More sharing options...
Krisboats Posted February 22, 2006 Report Share Posted February 22, 2006 Nah its nothing to do with the delay.Just did a google search and found thisYou can test this with a piece of paper and a matchbox car (which has free rolling wheels like an airplane… or like a car in neutral.) Place the paper on a table, and place the matchbox car on the paper. Take your hand, and hold the car still with a lightly placed finger on top of the car. At this point you are providing no forward thrust, and the “conveyor belt” is not moving. The car remains stationary. Now, continuing to hold the airplane with a lightly placed finger, and start to pull the paper out from under the car, in the backwards direction. According to Neal’s logic, the car should push back on your finger with the same force that you are exerting on the paper… but this is not what will happen. You will find that your lightly placed finger is not stressed to any noticeable extent. The paper will slide out, and the wheels will spin, but the car will not be propelled backwards. The reason for this is is that the rotation of the wheels is not related to the movement of the matchbox car except by the very small friction component of the axle, which your lightly placed finger can easily control.okay so what your missing out here is that when you press harder the paper slides out faster, this gives the same effect as just holding your finger still. I just did it with a little model car i had. It goes nowhere. Link to comment Share on other sites More sharing options...
oakley Posted February 22, 2006 Report Share Posted February 22, 2006 Read this dimwits Answer if you read down that it says that the plane WILL take off, the wheels will be travelling aproxemitley twice the speed of the conveyor belt, but thats the point, the conveyor is permanentley matching the speed of the conveyor so it is IMPOSSIBLE for the wheels to be going twice as fast!meaning, no lift!! Link to comment Share on other sites More sharing options...
Krisboats Posted February 22, 2006 Report Share Posted February 22, 2006 (edited) The aircraft is moving 10mph (X = X + 10) with the wheels rotating at 10mph. Therefore, the belt must react and accelerate to 10mph. But now the wheels are rotating at 20mph... and so on to infinity.it won't go on to infinity, this is where this argument comes to a halt, the wheels are moving at 20mph but the conveyer doesn't have to speed up does it. The plane is now stationary. When more thrust is applied the planes wheels are travelling at twice the speed that the conveyer is going at, butthe plane is still not going anywhere. Edited February 22, 2006 by Krisboats Link to comment Share on other sites More sharing options...
oakley Posted February 22, 2006 Report Share Posted February 22, 2006 If it goes on to infinity then the plane can never manage to go faster than the conveyer belt so will still be going nowhere.exactly Link to comment Share on other sites More sharing options...
nb88 Posted February 22, 2006 Report Share Posted February 22, 2006 The conveyer belt cant physically change the planes speed, only give resistance to the wheels. Say you have a rocket on top of a car in neutral, and as the car speeds up due to the rocket, the conveyer belt will go the same speed but in reverse as the car, but it can only give resistance to the wheels, not the car. As the wheels are free moving, they will continue to move forward due to the thrust from the rocket, but will need to go faster due to the extra resistance, so they will go about twice as fast, and the car will move forward. Link to comment Share on other sites More sharing options...
oakley Posted February 22, 2006 Report Share Posted February 22, 2006 but the wheels wont move twice as fast because the conveyor belt will keepup, and always be the same speed as the wheels, so they cant go twice as fast!!!they will go he same speed, thus meaning the car/ plane has no movement!! Link to comment Share on other sites More sharing options...
nb88 Posted February 22, 2006 Report Share Posted February 22, 2006 but the wheels wont move twice as fast because the conveyor belt will keepup, and always be the same speed as the wheels, so they cant go twice as fast!!!they will go he same speed, thus meaning the car/ plane has no movement!!It wont go the same speed as the wheels, itll go the same speed as the car.The conveyer belt cant change the speed of the car, it can only give resistance to the wheels. The thrust from the rocket/engine will continue to make the plane/car go forward, but the wheels will have to go twice as fast for that to happen. Link to comment Share on other sites More sharing options...
oakley Posted February 22, 2006 Report Share Posted February 22, 2006 so your trying to say the coveyor belt matches the speed of the car not the wheels?well thats a tottally different ball game!! joE! Link to comment Share on other sites More sharing options...
nb88 Posted February 22, 2006 Report Share Posted February 22, 2006 so your trying to say the coveyor belt matches the speed of the car not the wheels?well thats a tottally different ball game!! joE!No... thats the riddleAn aircraft is standing on a runway that can move (a conveyor belt). The aircraft moves in one direction, while the conveyor moves in the opposite direction. This conveyor has a control system that tracks the aircraft's speed and tunes the speed of the conveyor to be exactly the same, but in the opposite direction. There is no wind. The pilot begins to add thrust to the engines...The question is:Will the plane take off or not?The conveyer belt is equal and opposite to the speed of the PLANE not the wheels. Link to comment Share on other sites More sharing options...
Krisboats Posted February 22, 2006 Report Share Posted February 22, 2006 The car needs the wheels to roll though forwards though so if the wheels are on a surface that is moving at the same speed its the same as them not moving at all. The same as just lifting the car up and holding it still. Link to comment Share on other sites More sharing options...
nb88 Posted February 22, 2006 Report Share Posted February 22, 2006 The wheels are totally seperate from the plane/car, the speed of the plane isnt the speed of the wheels. The speed of the wheels is affected by the ground (i.e. conveyer belt), the speed of the plane is effected by the thrust of the engines in the air. Link to comment Share on other sites More sharing options...
PaRtZ Posted February 22, 2006 Report Share Posted February 22, 2006 (edited) I understand what you're saying joe, and i dont get why the wheels would be turning at double the speed of the conveyor.The wheels aren't travelling on the converyor, they stationary. so the conveyor is simply turning the wheels around at the speed of the conveyor. just because its facing backwards doesn't mean anything. Also just beacuse there is a force pushing the wheel forward, doesn't mean that the wheel will speed up, cos its still stationary...FORGET IT!! just watch some porn Edited February 22, 2006 by PaRtZ Link to comment Share on other sites More sharing options...
Krisboats Posted February 22, 2006 Report Share Posted February 22, 2006 Shit, i understand it now " the coveyor belt matches the speed of the car not the wheels" was all i needed for it to make complete sence. How did everyone else make it so damn complicated? All these examples of little cars and rockets and all that nonsense just made it too weird. Link to comment Share on other sites More sharing options...
oakley Posted February 22, 2006 Report Share Posted February 22, 2006 The wheels are totally seperate from the plane/car, the speed of the plane isnt the speed of the wheels. The speed of the wheels is affected by the ground (i.e. conveyer belt), the speed of the plane is effected by the thrust of the engines in the air.im with this guy if it is matching the speed of the car,, not the wheela, so the wheels will be moving at twice the speed and the car will go as fast as normal!!got another one though!!!the speedo would say it is going twice the speed as it is actually going, as speedos work through the wheels, so if the conveyor belt worked by measuring the speed through the speedo, then my intial theory was correct!!joE! Link to comment Share on other sites More sharing options...
Krisboats Posted February 22, 2006 Report Share Posted February 22, 2006 (edited) The plane is travelling at 5 miles an hourthe conveyer is travelling at 5 miles an hourbut because the wheels are free to spin as much as they like they are travelling at 10 miles an hour.the plane travels forwards at whatever speed it likes and the floor travels in the other direction at the same speed, but the only effect the floor has is that the wheels spin twice as fast, because the plane is still moving forwards.^^ is that basically it^^^ EDIT: yeah if it matched the speed of the vehicles speedo then it wouldn't go forwards. Edited February 22, 2006 by Krisboats Link to comment Share on other sites More sharing options...
Recommended Posts