Thread: The Case of the plane and the conveyor belt

Not without a rocket strapped to the tailplane !!!

The lift for flight is derived from the airflow over the wings creating a pressure differential and causing lift. In the case you mention there is no airflow over the wings as the plane remains static relative to the air around it .. hence no lift .. and no take off ...

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BRITSKI99:
Not without a rocket strapped to the tailplane !!! </div></BLOCKQUOTE>

That's pretty much how I see it.
However there is another school of thought that says, while the moving belt will cause the wheels to spin spin spin, this friction is not enough to counter the forward thrust of the jet engines. Hmmm does anyone have a model plane and a treadmill?

Keep'em flying

well, friction aside, the conveyor doesn't matter. The engines move the plane, they don't turn the wheels. It's not like in a car. So while the wheel speed may get to like 400mph, the airspeed would be independent of the wheel speed. The wheels are free spinning, the wheels don't move the aircraft. Thus, the aircraft would take off absolutely normally, it just may feel bumpy with the wheels spinning that fast.

The engines push the aircraft through the air. It wouldn't matter how fast the conveyor goes, as long as the wheels are free spinning enough. No matter the speed of the conveyor, the thrust of the engines in the air should overpower the conveyor. The air would remain static to the conveyor. The engines would simply overpower the conveyor if the wheels would spin free enough with no friction. The engines move the plane through the air, they don't move the plane along the ground. The ground condition should have no effect on the engine moving air.

I'm saying that the aircraft would accelerate forward regardless of the conveyor. The aircraft would accelerate just as normal, creating airflow over the airfoils, creating lift. In your car, the engine moves the wheels, they spin along the ground, displacing the ground. Car on a treadmill is going nowhere. However, an aircraft engine doesn't displace ground, it displaces air. Since the air is still, the engines would still displace that air and accelerate the plane forward through the air, creating airflow over the wings

Even if it did have a rocket engine, that wouldn't make a difference from a jet engine.

I'm in agreement with ColoAvs19. When I run at the gym I like to do the indoor track rather than the treadmill so I can feel the wind in my face. When I'm on the treadmill I remain stationary because the action of my feet and legs normally move me forward. However, an aircraft is different. It is moved forward by displacing air. The wheels are free spinning and therefore would not keep the aircraft from moving forward. It would eventually move forward with enough speed to create lift as it normally does. The spinning wheels underneath would spin faster than normal but would not prevent the planes forward momentum.

A previously stated the engines produce a forward thrust as said by moving the air from infront of the engine to behind it however this air motion itself will not create any lift over the aerodynamic lifting surfaces .. only the movement of the aerodynamic lifting surfaces through the air creates this lift. The crucial element is in the part of the question which states "you have the plane and the belt at the same speed but moving in opposite directions" so even though the aircraft and the belt may have wheel speeds corresponding to 500 mph there is still no resultant movement of the air over the aerodynamic lifting surfaces hence no lift and no take-off.

If it was possible don't you think someone would have developed this for use on an aircraft carrier before now??