Just for the record: If you have a plane on a runway that has been engineered to operate in such a fashion that all forward motion produced by thrust from the engines is matched by a contra force from this special runway to maintain the plane’s position relative to any fixed marker upon the airfield, then the pane can never move forward or backward on that runway.
Yes, if you exert a force on the plane that is equal and opposite to that of the thrust from the engines, then the plane will remain stationary wrt a fixed reference point. But that is not the case in the situation being described here.
As posited in post #1, the plane has its wheels on a conveyor which will always match the motion of the wheels but in an opposing direction. So if the wheel rotation is 10mph North the runway movement will counter with a motion 10mph South. If that is accepted, the plane can never move from its starting point relative to any fixed reference marker.
Incorrect. The wheels will never be able to move
themselves w.r.t. a fixed reference frame - but by exerting an additional force on the axle from the same fixed reference frame, the wheels will move with respect to the fixed reference frame.
Regardless of the thrust from the engines, they can never generate sufficient power to put sufficient airflow past the wings in and of themselves to generate the minimum aerodynamic lift required for take off.
Inclined to agree, otherwise aerplanes would only be able to hover above the same point on the ground. Instead of moving the plane from one "patch" of air to another "patch" at our destination, we would be bringing the "destination patch of air" here.
Engines generate thrust which move the plane forward (if it is not constrained from doing so by artificial devices or mechanisms) so that lift is generated by resultant airflow. If the plane is not moving through the air, no lift can be generated.
And this is the case here. There is no force or condition that is preventing the plane from moving through the air.
Although there seem to be a majority against my view on the thread the poll results currently show the majority supporting my view.
Of course, this is wholly unrelated to the "correctness" of the answers given. The laws of physics govern whether the plane will take off, not the responses to the poll.
I’d rather be right and have everyone else think I’m wrong than follow Captain Skills and the rest of the crowd on to his extremely interesting VTOL 747.
I think you would rather
think you are right than view the problem from the correct perspective. In this case, Bramble, you are wrong. The plane will take off.
If anyone else follows my reasoning and can come up with a more effective way of explaining it to those whom I have so miserably failed, please do take a shot at it.
On the contrary, it is infact US that have failed.
One last go, a thought experiment for you:
Could you do it with a toy aeroplane on an actual treadmill?
You could exert no force on the Model aeroplane and witness the behaviour of it remaining stationary with respect to the room you are conducting the experiment in (you would need to put a finger behind it, in order to overcome the forces of friction - but, compared to the scale of the forces we are considering, these are negligible).
Note: I am using a plane and a treadmill here, but the principal is better understood my imagining a marble on a piece of paper - you can pull the paper from underneath the marble and watch it stay in a fixed position with respect to, say, the table.
Now, given that you have a toy aeroplane on the treadmill, could you not push it forward with your finger? Yes, of course you could. Would the plane move wrt the room? Yes, of course it would.
Now, if you increase the speed at which the conveyor belt of the treadmill is moving, do you need to push the plane any harder to make it move the same distance with respect to the room? No, you do not. It doesn't matter whether the treadmill is going at 10mph or 100mph, the same amount of force is required to mobe the plane
with respect to the room.
This is the situation we have here, except we are replacing the source of the external force on the plane with jet engines attached to it, rather than a little poke along with One's finger.
