Can the plane take off?

OllieC said:
Currently no planes are taking off leaving people stranded at airports.
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My boss is headed to Texas tomorrow, and he's worried about being able to get back home. He said something like 700 flights were recently canceled.
 
Nater, both of my United flights were canceled for the trip I took last weekend from Chicago to Jacksonville and back. Tell him to check the app frequently. I never got any other notification other than the app was updated with the cancellation. No emails, no calls. Nothing. If I would have waited until I found out at the airport, I would have been screwed. Because I found out early via the app, I was able to get moved to another flight on American both times.
 
Went to NYC last weekend. Couldn't depend on the flights so cancelled them, drove to Albany, took the train. Very relaxing!
 
bajturner said:
Went to NYC last weekend. Couldn't depend on the flights so cancelled them, drove to Albany, took the train. Very relaxing!
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If that train was on a conveyor belt going the opposite direction, how long would that trip take?
 
I just read through this string and see that the group has put it to bed, just wanted to say that early on it was proved that the plane would not only not takeoff but it would not move at all from its location. As stated by one early on, if the conveyor started slowly to move towards the rear of the plane and then thrust was added to match that movement the plane would appear to be stationary as the conveyor moved underneath. That scenario would continue no matter at what speed and thrust were introduced as long as there were identical. Since the plane would not have any ground speed in this case it could not get any air speed either. My 2 cents..
 
R&A Nash said:
I just read through this string and see that the group has put it to bed, just wanted to say that early on it was proved that the plane would not only not takeoff but it would not move at all from its location. As stated by one early on, if the conveyor started slowly to move towards the rear of the plane and then thrust was added to match that movement the plane would appear to be stationary as the conveyor moved underneath. That scenario would continue no matter at what speed and thrust were introduced as long as there were identical. Since the plane would not have any ground speed in this case it could not get any air speed either. My 2 cents..
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Oh dear...
 
The physics of this is established, winged flight requires lift, wings create lift by moving at an appropriate speed thru the air to overcome gravity and friction. Propellers and jet engines do not create lift, but thrust which moves the plane forward once a ground speed appropriate for the size and weight of the aircraft is reached it will achieve lift. Since the conveyor is moving exactly at the same speed as the wheels regardless of how much thrust is introduced no ground speed can be obtained.
For anyone that has trouble grasping the physics here must not understand that ground speed is a must for a winged aircraft to have lift. You are stuck on the thrust being the relavent factor when it's not the case here. If your thinking that the length of the conveyor is a factor it is irrelevant, since the stated word problem states conveyor speed matches the wheel speed of the aircraft physics dictates the aircraft will not move from a POV from the side. Again no ground speed, no lift, that is the physics of it.
Now, explain why you think it will be able to achieve lift?
 
R&A Nash said:
The physics of this is established, winged flight requires lift, wings create lift by moving at an appropriate speed thru the air to overcome gravity and friction. Propellers and jet engines do not create lift, but thrust which moves the plane forward once a ground speed appropriate for the size and weight of the aircraft is reached it will achieve lift. Since the conveyor is moving exactly at the same speed as the wheels regardless of how much thrust is introduced no ground speed can be obtained.
For anyone that has trouble grasping the physics here must not understand that ground speed is a must for a winged aircraft to have lift. You are stuck on the thrust being the relavent factor when it's not the case here. If your thinking that the length of the conveyor is a factor it is irrelevant, since the stated word problem states conveyor speed matches the wheel speed of the aircraft physics dictates the aircraft will not move from a POV from the side. Again no ground speed, no lift, that is the physics of it.
Now, explain why you think it will be able to achieve lift?
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So instead of conveyor belt on a runway, the plane is hanging from cables attached to rollers in an overhead track that is the length of the runway, what would happen?
 
R&A Nash said:
The physics of this is established, winged flight requires lift, wings create lift by moving at an appropriate speed thru the air to overcome gravity and friction. Propellers and jet engines do not create lift, but thrust which moves the plane forward once a ground speed appropriate for the size and weight of the aircraft is reached it will achieve lift. Since the conveyor is moving exactly at the same speed as the wheels regardless of how much thrust is introduced no ground speed can be obtained.
For anyone that has trouble grasping the physics here must not understand that ground speed is a must for a winged aircraft to have lift. You are stuck on the thrust being the relavent factor when it's not the case here. If your thinking that the length of the conveyor is a factor it is irrelevant, since the stated word problem states conveyor speed matches the wheel speed of the aircraft physics dictates the aircraft will not move from a POV from the side. Again no ground speed, no lift, that is the physics of it.
Now, explain why you think it will be able to achieve lift?
Click to expand...
You’ve misunderstood the basic (and very limited) interaction between the wheels and the engine.

the wheels are free to spin at whatever speed they can spin before the bearings fail. Since they are free spinning there is nothing keeping the plane from moving forward. The belt just makes the wheels spin faster. The plane engine will pull the plane forward as if there was no conveyor belt. They tested this in real life and proved it.

if you can’t picture this then get a hot wheels car and a sheet of paper. Use one hand to simulate the plane engine and push the car forward. Use the other hand to pull the paper backwards. You’ll find that the car still moves forward.
 
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R&A Nash said:
The physics of this is established, winged flight requires lift, wings create lift by moving at an appropriate speed thru the air to overcome gravity and friction. Propellers and jet engines do not create lift, but thrust which moves the plane forward once a ground speed appropriate for the size and weight of the aircraft is reached it will achieve lift. Since the conveyor is moving exactly at the same speed as the wheels regardless of how much thrust is introduced no ground speed can be obtained.
For anyone that has trouble grasping the physics here must not understand that ground speed is a must for a winged aircraft to have lift. You are stuck on the thrust being the relavent factor when it's not the case here. If your thinking that the length of the conveyor is a factor it is irrelevant, since the stated word problem states conveyor speed matches the wheel speed of the aircraft physics dictates the aircraft will not move from a POV from the side. Again no ground speed, no lift, that is the physics of it.
Now, explain why you think it will be able to achieve lift?
Click to expand...
How about this...

If you were standing beside the conveyor belt looking at the plane, and the engines were throttled-up to full thrust, how fast would the conveyor belt have to go to hold the plane in place?

The power is not being imparted through the wheels to the conveyor belt so the speed of the conveyor does nothing but add a bit of additional resistance.
 
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