Airplane + Conveyor Belt
- Started
- Last post
- 74 Responses
- joyride0
If the conveyor could keep the plane motionless, the plane will not fly.
But the conveyor will not be able to do this. The thrust will pull the plane forward, the wheels will spin faster trying to keep it still, but they will just spin faster.
If you were to pull the plane with a string forward on the conveyor (=thrust) would it matter how fast the conveyor spins in the opposite direction?
- shilohous0
wrong, if the pull of the conveyor is equal to the thrust of the engine thrust, they cancel each other out and you have 0 ground speed, and 0 airspeed needed for lift.
all it is, is a huge waste of energy.
- ribit0
"Extra friction = slower plane = less uplift = no take off."
Extra friction= pilot puts in a bit more thrust. Easily overcome.
"disagrees. It's quite a drag and planes are very heavy, causing this drag."
The weight of the plane is a constant in both scenarios. All thats changed here is extra drag at the wheels (right?) Or have I missed another area of increased drag?
- planet010
the jets propel the plane, the wheels don't drive it. the conveyer belt can spin the opposite direction as fast as it wants, it won't matter. the plane is still going to pull itself forward through the air.
- ribit0
"wrong, if the pull of the conveyor is equal to the thrust of the engine thrust, they cancel each other out and you have 0 ground speed, and 0 airspeed needed for lift.
all it is, is a huge waste of energy"thats the thing... the pull of the conveyer is way less than the thrust of the engines. They dont cancel out.
- prophet0NE0
i'd say it would fly because the wings require the bernoulli effect to achieve lift, which wouldn't occur if the plane remained stationary.
http://scienceworld.wolfram.com/…
my physics knowledge is limited to watching bill nye the science guy and mythbusters, so...
- prophet0NE0
i meant "wouldn't fly". see i can't even spell.
- determinedmoth0
Extra friction= pilot puts in a bit more thrust. Easily overcome.
ribit
(Feb 14 06, 07:27)No! Planes aren't built to provide that extra thrust! There's no way it's as tiny as you think it is. It's probably several tonnes worth... A fighter jet maybe, but not an average plane.
- determinedmoth0
"wrong, if the pull of the conveyor is equal to the thrust of the engine thrust, they cancel each other out and you have 0 ground speed, and 0 airspeed needed for lift.
all it is, is a huge waste of energy"thats the thing... the pull of the conveyer is way less than the thrust of the engines. They dont cancel out.
ribit
(Feb 14 06, 07:29)Agreed on that point.
- todelete__20
no it would not be able to take off.
if the planes takeoff speed is 150mph and the conveyor can match that speed, the plane would actually not be moving on the belt.
just as a person doesn't move on a treadmill.
air pressure flowing over the wings is what makes a plane fly. if there is no air flowing over the plane it won't take off.
thus. no.
- wankerbez0
OM f-ing god
are you guys really trying to figure this out!!!it would be the same as having the brakes on!!!!!!!!!!!!!!!!
morons, how do you think they test the engines on the ground?
- Nairn0
Ribit, where you one of those bright kids in school who often got bad grades simply because you didn't read the question?
The conveyor belt serves to nullify any thrust or effect on/from the plane, therefore, the plane is 'stationary'.
In this scenario, the only way to achieve lift would be: a) if the motion of the conveyor belt itself created some freak bernoulli effect b) the volume of space used to conduct the experiment was restricted and designed such that the thrust from the jets created a pressure differential between the front of the experiment containing the jet and the back, pulling air across the wing surface forcing it to act as designed (imagine the jet sitting inside a tube barely large enough to fit the wings and fins - this, of course, would mean that the jet would hit an immediate vertical limitation - the top of the tube!). Outside, in the real world, the air would be drawn from the entire volume of air in front of the jet, and no pressure differential created - or, at least one too massively weak to do anything.
- shilohous0
well, it is supposed to be a kickss conveyer that can match the speed right?
- Nairn0
this is going no further than the innumerate ID threads..
- ribit0
"No! Planes aren't built to provide that extra thrust! There's no way it's as tiny as you think it is. It's probably several tonnes worth... A fighter jet maybe, but not an average plane."
Do you have any references for this 'several tonnes' amount? We're only talking increased wheel drag here...remember airspeed for takeoff is not increased.
- joyride0
wheels are freespinning right, then you will get a little friction. but the thrust will easily overcome that. the 2 forces are independent, thrust pulls the plane forward no matter how fast the conveyor is spinning
- ribit0
"well, it is supposed to be a kickss conveyer that can match the speed right?"
we've already established that the conveyer is matching the aircrafts speed...the question is how much of a drag component does that apply to the plane through its wheels.
- jakeyj0
so ribit - you are saying the plane has airspeed?
if i'm running on a treadmill my hair doesn't blow in the wind...
- Nairn0
no, what ribit's envisaging is a state where thrust and belt are expending so much energy, that the focus (the wheels) turn into an electromagnetic plasma, creating a frictionless interface between plane and belt, at which point the infinitely-thrusting plane will be able to overcome the belt's limitations and begin accelerating to air take-off speed.
i think.
I concede.
but I'm still right. :)
- joyride0
it would if you sat on a turbine engine with wheels on it... =)
If you put a plane on a conveyor belt with a string attached. Pull the plane forward... what happens to the wheels as the conveyor tries to go faster. they go faster. The only way to negate the pull of the string forward is to have something pulling it in the opposite direction. Freewheeling wheels do not achieve this.