Korean Job Discussion Forums

[johndoe]

[soju pizza]

I heard Labradors were smart.

[SeoulFinn]

It'll fly. Why? The plane gets its forward momentum from the jet engines and not from the tires like cars. No matter how fast the wheels turn to the "wrong" direction, the plane would still move forward and gain speed and lift off. It doesn't matter how fast the tires turn (forward or backwards).

IT WILL FLY.

Edit/addition: "If there is no wind and no other forces other than the friction of the wheels, then the P value in the equation will = zero, causing the equation to = ZERO lift."

By moving forward the plane will create its own "wind/lift" that will make the plane lift off. According to you, no plane would ever lift off at an airfied that has temporarily no wind at all. LOL!

(Damn typos!)

[JustJohn]

Didn't read the thread. Question is easy. Answer is yes.

Quick explanation. If the belt is going backwards at normal takeoff speed then the plane has to go twice normal takeoff speed to take off. But given that it has infinite thrust and structural integrity this should pose no problem whatsoever.

As a matter of fact, the belt could be moving backwards infinitely fast, as long as the degree of infinity was less than that of the the thrust.

Edit #1:
Looks like the guy above me got it right. Other people need to read the question more closely.

Edit #2:
Also, if the plane turns around it can take off without even firing up the engines. Of course, it wouldn't stay up long without them.

[Underwaterbob]

The plane will not fly. The only forces acting on it are the engines and the friction between the wheels and the conveyor belt (not that this even matters). There is no lift. The question also stipulates that the conveyor belt is moving such that the plane remains stationary relative to whatever this infinitely long conveyor belt is sitting on. Which is also presumably stationary relative to the air (presuming there is any). So if the plane is stationary relative to the air and there is no wind it can't even create any lift were there any upward forces acting on it anyway which there aren't because even if this infinitely powerful indestructible plane had flaps they would be useless since it's stationary relative to the air anyway! Of course it all depends on whether this thing is a harrier or not (can tilt it's engines) in which case it doesn't need a runway anyway. Just watch out when you turn on those infinitely powerful engines because regardless of whether it's indestructible or not likely the person flying the plane or the entire plane will create some kind of space-time anomaly as the entire mess instantly acquires light speed probably destroying a good chunk of the universe. (But that last part is purely hypothetical and not even based on any good evidence anyway since no one knows what would happen if something of that mass instantly acquired light speed)

Ask a physicist or engineer this question and they will just groan and roll their eyes at you, there is just too much unknown and most of what is known is impossibly ridiculous.

[mateomiguel]

If it was a car with wings, the conveyor belt and wheels would be important, because the plane would be trying to drive down the moving conveyor belt to gain speed to take off. With its wheels.

However, a plane's forward motion comes from its jet engines, not its wheels, so it would just need to crank up the juice on its jet engines in order to overcome the backward motion of the conveyor belt, gain speed, and eventually take off. When the plane was still on the conveyor belt trying to take off the only difference from a normal runway would be the wheels spinning faster than normal. But the airplane has infinite structural integrity so you don't have to worry about over-taxed wheels falling off or anything.

I don't think the backwards motion of the conveyor belt is a significant force, because the jet engines aren't acting on it. They are acting on the surrounding air which is unaffected by the conveyor belt.

Wait is this a variable speed conveyor belt that matches the thrust from the infinitely strong engines? Because who is the dude who keeps adjusting the speed of the belt? We need to find him, take him out, and everything will work fine.

[JustJohn]

What the heck. Did he just change the question? I could have sworn it said the belt was going at take-off speed, and now it says it changes to however fast the plane is going.

Questions remains easy, but the answer is different. Obviously if it's going at the plane's speed it will never take off. No airspeed = no lift.

[SuperFly]

I didn't change anything, if I had changed anything...there'd be an edit log at the bottom of the post. It's fun to see people argue about this subject.