Lightning McQueen
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you can't leave, I haven't finished me popcorn yet! ![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Don't go Skills - I don't want to win by default...Sigh...
If the engine is switched off, yes. If not, no.
Since you cannot get past this basic point, seriously, I am leaving.
If the conveyor is set up to exactly match the speed of the plane's wheels, does that mean that regardless of the speed of the conveyor, the plane will not be moving relative to the ground upon which the conveyor sits? Is my analysis, so far, correct?
Don't go Skills - I don't want to win by default...
Either the coveyor is rigged to match the speed of the plane or it's not. Which is it? There was no mention of the engines mystically communicating their condition with either the wheels or the conveyor in your post #1.
The conveyor is spinning the wheels! They will always match.
Most people can push a car that is not in gear along a flat road, not very fast, but they can still move it. Now put the car on a conveyor and while standing on firm ground, push against the car when the conveyor is switched on at 10mph. The wheels move at 10mph but the car is going nowhere. Now, increase the speed to 20mph, 30mph, 40..50...even at 100mph the energy needed to push against the car to keep it stationary doesn't increase (assuming minimum wheel bearing friction). Now, push just a little harder and the car will move forward against the conveyor, even if the wheels and conveyor are moving at 500mph.
WHAT!!! This is not the detail in post #1. Which one are we solving for? The original one or this new one?OK, Bramble:
The conveyor belt merely causes the wheels to spin, frictionlessly, on their axels. The plane does not move in any way due to this. It only moves when the engine is switched on.
Say the belt is moving at a billion miles an hour. The wheels are, in turn, spinning at a billion miles an hour (rotational speed.)
THE NET FORCE ON THE PLANE IS ZERO - the wheels are spinning on their axes, the plane is not moving at all.
Now, the engines are switched on - THE NET FORCE ON THE PLANE BECOMES POSITIVE - the plane takes off!!!!
WHAT!!! This is not the detail in post #1. Which one are we solving for? The original one or this new one?
you can't leave, I haven't finished me popcorn yet!![]()
|So, let's pretned the wheels are merely used to determine the speed of the plane over the surface of the conveyor. If the conveyor is always moving at the same speed, but in an opposite direction to the wheels, regardless of the speed, the net forward motion of the plane relative to the ground upon which the conveyor is standing is 0 mph. Have I got that right?Imagine a 747 sitting on a very large conveyor belt. The belt has the same dimensions as a runway at an airport*, and is set up to exactly match the speed of the plane's wheels, moving in the opposite direction.
I'm eagerly awaiting the sh*tstorm that the "plane on a treadmill" will generate
|So, let's pretned the wheels are merely used to determine the speed of the plane over the surface of the conveyor. If the conveyor is always moving at the same speed, but in an opposite direction to the wheels, regardless of the speed, the net forward motion of the plane relative to the ground upon which the conveyor is standing is 0 mph. Have I got that right?
If I have, where does the 180 mph breeze necessary to provide sufficient lift to loft the bastie upward come from?
Skills, I don't want to get side-tracked onto cars and stuff. I'm having a tough enough time trying to pin you down on what you really mean in post #1.The key point, by the way, in new_trader's post is, the car is not in gear. This is exactly the same for these purposes as a plane whose wheels do not create forward motion.
Please get this through your bloody skull so I can go and cry in my pillow.
YES IT BLOODY IS! WHAT SORT OF PLANE DO YOU KNOW THAT DRIVES THROUGH ITS WHEELS???
AAAAAAAAAAARGH
NO. Never flown multi-engine. I just 'treated myself' to a PPL 7 years ago and fly fairly regularly still. I reckon that puts me in the 5% most likely to at least be aware of the physical realities and practicalities of aerodynamic flight.
|So, let's pretned the wheels are merely used to determine the speed of the plane over the surface of the conveyor. If the conveyor is always moving at the same speed, but in an opposite direction to the wheels, regardless of the speed, the net forward motion of the plane relative to the ground upon which the conveyor is standing is 0 mph. Have I got that right?
If I have, where does the 180 mph breeze necessary to provide sufficient lift to loft the bastie upward come from?