Plane on a conveyor belt
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That's a big 10-4 on the 3 in the morning biz. If I hadn't slept all day cuz I was working all night last night I'd be in bed so long ago. The gravity holding the plane down on the belt as a way of holding it from moving horizontally is negated by the magic of the ever popular assumed frictionless bearings. Lots of assumptions and whatever in all this bizness, interesting question Chuck
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ok, heres my take....you need the airflow above and below the wings to make the plane leave the ground. If you've ever run on a treadmill, you'll know that you get hot because no matter how fast you run, there is no airflow going over your body. If you run around a track or outside or something, the airflow will cool your body.
With no airflow, the plane stays on the ground.
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So, Dubbsy
Explain too me why the foreword thrust wouldn't move the tires more.Plane has thrust on it's body, pushing the plane a 50mph, the wheels, attached to the plane, spin at 50. The "Treadmill" spins at 50.
The plane has thrust pusing it's body too 100mph, that means the plane needs too acelerate, forewords, because we need too go forwords to generate lift, we all know that.
so, if the plane goes forword, the wheels turn forword, the Treadmill matches the wheels.Which means it matches the plane.
Which means that it doesn't matter what speed the Jets are pushing the plane, the wheels are going that fast too, and as long as they are, the treadmill is matching.
I understand what u are saying, but, it's not possible too me.
If u can explain it, please do.
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Sweet-WRX-Lovin wrote:
They negate each other. The only force left acting on the plane is the thrust of the engines. This is the only force left (magically of course). Since it is the only force left, the plane moves forward and takes off.
For the plane to move forword, the wheels must move forword, which means the tradmill moves the other way.Unless u can kill my theory.
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Phats wrote:
So, Dubbsy
Explain too me why the foreword thrust wouldn't move the tires more.Plane has thrust on it's body, pushing the plane a 50mph, the wheels, attached to the plane, spin at 50. The "Treadmill" spins at 50.
The plane has thrust pusing it's body too 100mph, that means the plane needs too acelerate, forewords, because we need too go forwords to generate lift, we all know that.
so, if the plane goes forword, the wheels turn forword, the Treadmill matches the wheels.Which means it matches the plane.
Which means that it doesn't matter what speed the Jets are pushing the plane, the wheels are going that fast too, and as long as they are, the treadmill is matching.
I understand what u are saying, but, it's not possible too me.
If u can explain it, please do.
that is what i was thinking, but that is in a perfect world.
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I just thought of an explanation/analogy, let me know what you guys think of it.
Reading a couple of the posts here, people like to try to think of this in terms of a treadmill, so we will use that.
Imagine standing on a treadmill wearing a pair of rollerblades. Now, someone is standing behind you (off of the treadmill). Turn the treadmill on, and have the person behind you push you forward. Do you start moving forward in relation to the ground? Hopefully, the answer is yes.
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Phats wrote:
For the plane to move forword, the wheels must move forword, which means the tradmill moves the other way.Unless u can kill my theory.
With the assumptions I am making about the wheels of the plane and everything else the conveyor could be actually moving in the direction the plane wants to go or the opposite as in this case at ludicrous speed (or infinite velocity) and the plane would still not move. A body at rest will stay at rest, unless it is acted upon by a force. In my magic frictionless scenario the only force on the plane is its own thrust and I guess of course aerodynamic resistance as it accelerates which is needed to fly.
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Ok, time to put this to rest
Think about it this way if you are driving a motorcycle with a side car on it at 50MPH and the conveyor is ONLY on the side car you can still drive the motorcycle at 50MPH, however the sidecars wheel(s) will be traveling 100MPH. Same principal applies here. The planes motors providing thrust would be the motorcycle in above analogy and the planes wheels would be the side car. It is very possible for the plane to take off.
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I think I know why Kirkeide quit.
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Phats wrote:
So, Dubbsy
Explain too me why the foreword thrust wouldn't move the tires more.Plane has thrust on it's body, pushing the plane a 50mph, the wheels, attached to the plane, spin at 50. The "Treadmill" spins at 50.
The plane has thrust pusing it's body too 100mph, that means the plane needs too acelerate, forewords, because we need too go forwords to generate lift, we all know that.
so, if the plane goes forword, the wheels turn forword, the Treadmill matches the wheels.Which means it matches the plane.
Which means that it doesn't matter what speed the Jets are pushing the plane, the wheels are going that fast too, and as long as they are, the treadmill is matching.
I understand what u are saying, but, it's not possible too me.
If u can explain it, please do.
You're looking at it wrong...
I think there's a very big thing here that everyone is totally looking past, but I can't figure out how to explain it so people will understand it...Imagine that the wheel bearings are 100% efficient and produce no friction. The plane would stay in the very same spot no matter what direction the conveyor moved...forward or back. Now the actual efficiency of the bearing isn't that bad so they are free to roll as they wish, however they will drag the plan with them a bit... BUT, it's not enough to keep the plane in one spot.
look at chucks analogy because it just about perfectly describes this..
if the motorcycle has a speed of 50mph, the conveyor is spinning 50mph the opposite direction. The wheel on the side car however is spinning at the combined speeds of the conveyor and the motorcycle...
Now to bring friction into this.. the motorcycle will have to work a bit harder to reach 50mph than if they were on a static surface because they have to fight the little bit of friction in the side-car wheel (although, I did read that the friction in the wheel bearing doesn't change from 50 to 100mph (or any other speed), so this may not be applicable).now throw that over to the plane. The Jet engines are the motorcycle.. The motorcycle pushes the side-car, the jets push the plane. The motorcycle force is acting on static ground while the jets are acting on the static air above the conveyor.
The only time that thrust is applied AND the speed of the plane is zero is when the brakes are applied. **It defies the limits of the question **to say that the conveyor is moving and the plane is staying in one spot, because if the plane is sitting in one spot then it's speed is zero. The question says the conveyor matches the plane's speed, so therefore the conveyor would not move. If neither are moving, then what's holding the plane in one spot with thrust applied? brakes?
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I win.
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Sweet-WRX-Lovin wrote:
I think I know why Kirkeide quit.No, I think she actually liked me Schulzy. The school board on the other hand.......:rolleyes:
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I in no way meant you. Too bad they couldn't work something out, she was the best.
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Everyone who have posted on here are right, unless there are proves to prove them wrong.
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I CAN prove you wrong and did with my analogy. Its not much different than if a plane flew over a moving conveyor belt that was moving the opposite direction at the same speed as the plane...only difference would be that the wheels aren't touching the conveyor belt. You could do a touch-and-go with a plane on a moving conveyor belt as well.
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Nobody gave me feedback on my rollerblades on treadmill analogy, it must not be very good
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