The plane would eventually take off once it got to 25 mpg relative to the ground in forward movement. But the way the myth is decievingly worded, the question is would it take off at the moment it was stationary when the wheels where going 25mph on the belt and the belt was going the opposite direction at 25mph. And it would, for a moment, be stationary relative to the ground as it went from going backwards to going forwards.

quote:

---

this thread makes me want to kick my cat across the room

---

i dont need any motivation...cats do suck indeed

tex is moot

did anyone really think a plane would take off if it was sitting still?? that was never the question. that's just logic. if that is what was tripping you up, you've got serious problems

nay....

intelligence is moot

quote:

---

The plane would eventually take off once it got to 25 mpg relative to the ground in forward movement. But the way the myth is decievingly worded, the question is would it take off at the moment it was stationary when the wheels where going 25mph on the belt and the belt was going the opposite direction at 25mph. And it would, for a moment, be stationary relative to the ground as it went from going backwards to going forwards.

---

Wow.

What ****ing myth are you talking about, texaggie7nine? It certainly isn't the one that we spent 40+ pages discussing.

The wheels on an airplane do only three things.
1) They are there to act as place holders for the aircraft. They allow the aircraft to stand in any one place and be easily moved to another place by what ever force be it tractive such as from a tow or under it's own power via thrust.
2) They allow the pilot to steer the aircraft while on the ground.
3) Upon landing they allow the pilot to apply braking force toward slowing and ultimately stopping the aircraft.

That is all. With the brakes disengaged the wheels do nothing but freewheel like the wheels on a skateboard. The reason that the airplanes as tested and aircraft in the imaginary scenario does move and ultimately take off is because the wheels of the aircraft are freewheeling. They are not providing tractive force to the aircraft. They do nothing at all but freewheel and support the plane off the ground.

What does move the plan forward and to take off is thrust and thrust is not dependent on nor affected by the ground or ground speed or the infinite speed possibility of the imaginary uber treadmill.

The key to aircraft moving at all muchless taking off is thrust, which is not a force dependent on nor affected by traction with the ground/surface/treadmill as are humans, horses, and automobiles.

simplified can u post ur allsome emticon face?

quote:

---

did anyone really think a plane would take off if it was sitting still??

---

The idiot coworkers that told me about this myth in the first place did.

Simplified's explanation is the best one I've read yet.

[This message has been edited by Red Skye (edited 1/31/2008 10:32a).]

good explanation....

now lets kill this thread

i like my new modified one

dp

[This message has been edited by jokershady (edited 1/31/2008 10:27a).]

quote:

---

What ****ing myth are you talking about, texaggie7nine? It certainly isn't the one that we spent 40+ pages discussing.

---

The one my coworkers told me, and the one the mythbusters worded on last night's show. WTF would I read any of this thread?

that one doesnt do it for me simp..

and

quote:

---

The idiot coworkers that told me about this myth in the first place did.

---

tex, i recommend that you go to your co-worker and kick him in the junk immediately

your coworkers are wondering which one is the idiot.

thanks flaith

quote:

---

sorry, they are moving in the opposite directions .

---

Here is your statement:

quote:

---

If a car is going 50 mph relative to stationary and it is on a belt going 50 mph relative to stationary, they are boing going the same speed. This means that the wheels on the car are spinning at 100mph.

---

If they are going in opposite directions, why do their velocity magnitudes have the same sign?

quote:

---

this thread makes me want to kick my cat across the room

---

]

Texags is hth!!!

alllllsooooommmeeee

A plane's lift is based on air speed, the speed of the wind over the wings. This reminds me of the myth they did with the car driving up the back of a semi, they were convinced it would suddenly accelerate and slam into the front of the truck, which of course didn't happen. But unlike a car, a plane isn't "driven" by it's wheels.

The big problem here is whether the speed the plane is traveling is air speed or ground speed. If the ground speed of the plane and the conveyor belt speed are the same, the plane won't be able to take off. Think walking the wrong way on a moving sidewalk at the airport or an escalator at the exact same speed, you go nowhere.

However, if the speed they are basing it on is air speed, meaning the speed of the wind over the wings is greater than the stall speed for the plane, then the wings should be able to generate the lift to take off, but there are some other complications as to whether it would actually leave the ground. In that case, it's tough to tell and I could see why the scale models would have problems. My guess if that's the case is no though.

quote:

---

The big problem here is whether the speed the plane is traveling is air speed or ground speed. If the ground speed of the plane and the conveyor belt speed are the same, the plane won't be able to take off. Think walking the wrong way on a moving sidewalk at the airport or an escalator at the exact same speed, you go nowhere.

---

where are all these idiots coming from?

die

Thats true - plus if the plane isn't moving relative to the ground there is no way there could be airspeed.

At least agman doesn't have his degree yet.

simplified



post of the year.

quote:

---

If they are going in opposite directions, why do their velocity magnitudes have the same sign?

---

They are moving in mph relative to the ground. It doesn't matter what direction as far as the mph is concerned.

quote:

---

They are moving in mph relative to the ground. It doesn't matter what direction as far as the mph is concerned.

---

It does if you want the wheels to move 100 mph...

I think the real question is...

If you put Texaggie7nine on a conveyor belt, would he get that the plane takes off?

[This message has been edited by Ag with kids (edited 1/31/2008 11:11a).]

seriously, some of you shouldn't be allowed to breed

quote:

---

It does if you want the wheels to move 100 mph

---

well the friggin opposite direction is already a given.

Not in your problem statement...