So are you saying the belt has zero effect on the plane? Zero, Nada, Nil?
Negligible. There is some parasitic force on the plane because of resistance to spin in the wheels from inertia and friction. Otherwise, all force on the wheels translates to acceleration of the wheels. Remember physics where velocity is the speed along a specific vector for a period of time. Changing the vector is acceleration. F = ma. Assume mass =1 and F=a. A=dV/dt. So, just the wheels spin because that is how they work. Since they freewheel (except for that parasitic stuff), nothing on the plane allows energy the wheels store effect the plane. If you applied the brakes, then you translate the energy into heat and force on the plane, but only then.Originally posted by: KK
So are you saying the belt has zero effect on the plane? Zero, Nada, Nil?
I have Neal on. He has a link to Mythbusters on his news. I sent a note reminding him that when he first read the conveyor thing, he was skeptical for about 3 minutes. I clearly remember calling him a moron (he did not hear me telling it to my radio), but then he got it right. He is going to help Royal wash his plane now (besides the $105 bucks he won).Originally posted by: Queasy
Heh. I was listening to Neal Boortz on the way into work this morning (he's a private airplane aficionado and has been talking about this on the air). He had bet his producer that the plane would take off. He won obviously but he read some of the email he had gotten from listeners. Some were claiming that they were pilots and aeronautical engineers with degrees from Virginia Tech, etc. and that the plane would not take off. They were wrong. It was kind of funny to hear them. Especially the ones emailing in after the show claiming that the test was done wrong.
Wish he had posted some of them up on his site.
Originally posted by: BigDH01
I can't believe there is still debate. The plane takes off, OBVIOUSLY.
Originally posted by: BigDH01
I guess this problem is simply too complicated for many people to understand. That scares me.
Originally posted by: gsellis
Negligible. There is some parasitic force on the plane because of resistance to spin in the wheels from inertia and friction. Otherwise, all force on the wheels translates to acceleration of the wheels. Remember physics where velocity is the speed along a specific vector for a period of time. Changing the vector is acceleration. F = ma. Assume mass =1 and F=a. A=dV/dt. So, just the wheels spin because that is how they work. Since they freewheel (except for that parasitic stuff), nothing on the plane allows energy the wheels store effect the plane. If you applied the brakes, then you translate the energy into heat and force on the plane, but only then.Originally posted by: KK
So are you saying the belt has zero effect on the plane? Zero, Nada, Nil?
Originally posted by: abaez
I think my problem is that if I'm perpendicular to the treadmill and I am looking at the plane, the way I understand it is that the plane would not move forward with me looking straight at it. It would not go forward because the treadmill is basically "taking" the ground from under it and the plane is not moving forward. That's just how I see it - everyone says it's wrong, but since people say the treadmill cannot counteract, I just can't visualize it correctly.
If you take it another way, say a plane is landing onto a conveyor belt and the conveyor belt is matching the planes forward speed - if it lands on the belt perfectly wouldn't it just stay in the exact place it touched the ground not going forward? My mind tells me it would, but I'm sure it's wrong.
Originally posted by: KK
Originally posted by: gsellis
Negligible. There is some parasitic force on the plane because of resistance to spin in the wheels from inertia and friction. Otherwise, all force on the wheels translates to acceleration of the wheels. Remember physics where velocity is the speed along a specific vector for a period of time. Changing the vector is acceleration. F = ma. Assume mass =1 and F=a. A=dV/dt. So, just the wheels spin because that is how they work. Since they freewheel (except for that parasitic stuff), nothing on the plane allows energy the wheels store effect the plane. If you applied the brakes, then you translate the energy into heat and force on the plane, but only then.Originally posted by: KK
So are you saying the belt has zero effect on the plane? Zero, Nada, Nil?
But there is some, negligible at best, but that's all that's needed for people interpret this question in a different light. Mythbusters did it their way, but with most of the naysayers, they would say mythbusters didn't do it right per the question they heard or how they interpreted it. I don't think this is so much of a problem with physics but more to do with comprehension.
Originally posted by: PurdueRy
Originally posted by: KK
Originally posted by: gsellis
Negligible. There is some parasitic force on the plane because of resistance to spin in the wheels from inertia and friction. Otherwise, all force on the wheels translates to acceleration of the wheels. Remember physics where velocity is the speed along a specific vector for a period of time. Changing the vector is acceleration. F = ma. Assume mass =1 and F=a. A=dV/dt. So, just the wheels spin because that is how they work. Since they freewheel (except for that parasitic stuff), nothing on the plane allows energy the wheels store effect the plane. If you applied the brakes, then you translate the energy into heat and force on the plane, but only then.Originally posted by: KK
So are you saying the belt has zero effect on the plane? Zero, Nada, Nil?
But there is some, negligible at best, but that's all that's needed for people interpret this question in a different light. Mythbusters did it their way, but with most of the naysayers, they would say mythbusters didn't do it right per the question they heard or how they interpreted it. I don't think this is so much of a problem with physics but more to do with comprehension.
If you wanted to keep the plane stationary the treadmill would have to run at speed MUCH faster than the forward velocity of the plane. This would contradict the myth as stated. There is NO statement in the myth that says the plane will stay stationary. The only people that say this are the people that think a plane is a car with wings.
Originally posted by: mrSHEiK124
Alright. I'll try and be civilized.
A treadmill can do ABSOLUTELY NOTHING to stop an airplane from moving.
If you wanted to keep the plane stationary the treadmill would have to run at speed MUCH faster than the forward velocity of the plane.
Originally posted by: LTC8K6
It's unrealistic to claim that the treadmill can stop the plane, imo.
There is no reasonable way for that to occur.
Originally posted by: biggestmuff
Technically speaking (see FAA FAR 103), the myth still hasn't been tested as an ultralight in not an aircraft.
Just adding fuel to the fire.
/runs and hides
Originally posted by: sixone
Originally posted by: abaez
I think my problem is that if I'm perpendicular to the treadmill and I am looking at the plane, the way I understand it is that the plane would not move forward with me looking straight at it. It would not go forward because the treadmill is basically "taking" the ground from under it and the plane is not moving forward. That's just how I see it - everyone says it's wrong, but since people say the treadmill cannot counteract, I just can't visualize it correctly.
If you take it another way, say a plane is landing onto a conveyor belt and the conveyor belt is matching the planes forward speed - if it lands on the belt perfectly wouldn't it just stay in the exact place it touched the ground not going forward? My mind tells me it would, but I'm sure it's wrong.
The problem with the first paragraph is that you're ignoring the fact that the propeller/engines are moving air past the plane as well, which gives it forward movement, regardless of whether the ground is moving or not.
If the plane is landing on the conveyor belt, it also has forward momentum, so it can't possibly stay in the same place. No conveyor belt can counteract that.
Originally posted by: KK
Originally posted by: PurdueRy
Originally posted by: KK
Originally posted by: gsellis
Negligible. There is some parasitic force on the plane because of resistance to spin in the wheels from inertia and friction. Otherwise, all force on the wheels translates to acceleration of the wheels. Remember physics where velocity is the speed along a specific vector for a period of time. Changing the vector is acceleration. F = ma. Assume mass =1 and F=a. A=dV/dt. So, just the wheels spin because that is how they work. Since they freewheel (except for that parasitic stuff), nothing on the plane allows energy the wheels store effect the plane. If you applied the brakes, then you translate the energy into heat and force on the plane, but only then.Originally posted by: KK
So are you saying the belt has zero effect on the plane? Zero, Nada, Nil?
But there is some, negligible at best, but that's all that's needed for people interpret this question in a different light. Mythbusters did it their way, but with most of the naysayers, they would say mythbusters didn't do it right per the question they heard or how they interpreted it. I don't think this is so much of a problem with physics but more to do with comprehension.
If you wanted to keep the plane stationary the treadmill would have to run at speed MUCH faster than the forward velocity of the plane. This would contradict the myth as stated. There is NO statement in the myth that says the plane will stay stationary. The only people that say this are the people that think a plane is a car with wings.
I don't believe many people actually believe that last sentence, atleast I hope not. I'd like to see the actual original myth if possible, not the version that mythbusters got handed, but the original.
Originally posted by: randay
what the fuck. how in the hell do people still not get this? this thread makes me lose faith in all life on earth.
"On a day with absolutely calm wind, a plane is standing on a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyor moves in the opposite direction. The conveyor has a control system that tracks the plane speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Can the airplane ever take off?"
Originally posted by: mrSHEiK124
Originally posted by: abaez
I think my problem is that if I'm perpendicular to the treadmill and I am looking at the plane, the way I understand it is that the plane would not move forward with me looking straight at it. It would not go forward because the treadmill is basically "taking" the ground from under it and the plane is not moving forward. That's just how I see it - everyone says it's wrong, but since people say the treadmill cannot counteract, I just can't visualize it correctly.
If you take it another way, say a plane is landing onto a conveyor belt and the conveyor belt is matching the planes forward speed - if it lands on the belt perfectly wouldn't it just stay in the exact place it touched the ground not going forward? My mind tells me it would, but I'm sure it's wrong.
Alright. I'll try and be civilized.
A treadmill can do ABSOLUTELY NOTHING to stop an airplane from moving.
Now that that's out of the way, let's address both paragraphs of your post. Ignore the wheels on the airplane; it has no wheels. If you want wheels there, that's fine too; point is an airplane's wheels have absolutely nothing to do with how it takes off. The pilot turns on the engines, they spin up, and begin to suck air through them. The airplane moves forward, skidding across the treadmill if it's got no wheels, and rolling with the wheels at 2x the speed they regularly would if the wheels are still there.
Second paragraph. If an airplane lands on a treadmill matching it's forward speed, it'll keep going forwards just as it was. It amazes me how much the NUMBNUTS that believe it won't take off ignore THIS PICTURE: http://www.math.hmc.edu/baldyconf/JetBlue292Landing.jpg
How the hell do you think it landed yet STILL MOVED with wheels that were jammed SIDEWAYS? *DING DING* THE WHEELS HAVE GOT SHIT TO DO WITH HOW AN AIRPLANE WORKS. The force moving the airplane comes completely from the jet engines, otherwise according to "it doesn't take off" logic, as soon as an airplane brought its landing gear up (I wonder why they call it landing gear, BECAUSE THAT'S THE ONLY REASON IT NEEDS TO EXIST) it would fall out of the sky because the wheels weren't putting power to the ground anymore....
Originally posted by: LTC8K6
"On a day with absolutely calm wind, a plane is standing on a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyor moves in the opposite direction. The conveyor has a control system that tracks the plane speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Can the airplane ever take off?"
Mythbusters just answered that twice.
The airplane will take off as if it was on a stationary runway.
Originally posted by: BigDH01
Originally posted by: LTC8K6
"On a day with absolutely calm wind, a plane is standing on a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyor moves in the opposite direction. The conveyor has a control system that tracks the plane speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Can the airplane ever take off?"
Mythbusters just answered that twice.
The airplane will take off as if it was on a stationary runway.
You should go to the Discovery forums and tell them this. From the first few pages of the forum thread, it would appear that the number of people that say it won't fly still outnumber the people that say it will. This leads me to one of two conclusions:
1) people still aren't bright enough to get it
2) people are too stubborn to admit they are wrong
Either way, does humanity really stand a chance? We keep developing new cutting edge technologies but is the majority of the population actually able to understand the technology and its consequences? Is humanity smart enough to survive?