/munches on more popcornFreke1 wrote:
This topic has had 6712 replies and 246130 views on the physorg forum so be prepared for a long discussion:
http://forum.physorg.com/index.php?showtopic=2417
/refills with cheddar flavor
/passes out a karma or two
/clicks on link and needs bigger bowl of popcorn
KJ
lol..except if we solve that one and post it here, the owner of this site is likely to become very, very richValium500mg. wrote:
This is a simple thing, you guys should be debating (nice word for arguing) why Qua tum mechanics is right and General relativity is right but why do they disagree? maybe I'll start a new thread if I do I'll call it Super string theory.
correct me if i'm wrong here, but isn't the whole point of this treadmill to eliminate the need for a runway?Sk wrote:
yeah.. that's all well and good.. but who agreed the plane wasn't moving?-=]NS[=-Eagle wrote:
They way a plane works is as follows: The airfoil creates lift because of a high pressure system created under it. This is all explained in Bernoulli's principle. The way the airfoil is shaped makes it so when air hits it, the air particles that go over the airfoil have to travel a longer distance than the particles that go under it. And since air particles must all move at the same speed, the air that goes over the air foil must move faster to keep up with the air that goes under it. This creates low pressure above the airfoiil which allows the high pressure beneath it to push it up. SO if the plane wasn't moving, there wouldn't be any air moving over the airfoil to lift the plane up, therefore making the treadmill useless.
Thank you for your time :-P
otherwise, we are arguing about whether planes need a runway at all to take off. as soon as the plane begins moving forward relative to the bystander, it is essentially using a runway, which we are trying to eliminate. please read my post on page 8 for your response from me.
i'll reiterate for those that don't care to.
THE ONLY THING WE ARE CONCERNED ABOUT IS WHETHER THE SURROUNDING AIR IS MOVING RELATIVE TO THE WING. THIS is what matters, this is an issue of relativity. not how fast the plane is moving relative to us, or relative to the treadmill. airflow creates the pressure gradient that allows for the lift. no airflow, no lift.
Remember Me As A Time Of Day
not so there is very little to be gained in this field other than a paycheck. I mean you can't patent a universal law
yes cuz a plane is not using its wheels to move there for an opsite moving tread mill would only make the wheels move twice as fast.
lol I like the Garry's mod video
yes, you're right.. relative speed between plane and treadmill makes no difference.heggs wrote:
correct me if i'm wrong here, but isn't the whole point of this treadmill to eliminate the need for a runway?Sk wrote:
yeah.. that's all well and good.. but who agreed the plane wasn't moving?-=]NS[=-Eagle wrote:
They way a plane works is as follows: The airfoil creates lift because of a high pressure system created under it. This is all explained in Bernoulli's principle. The way the airfoil is shaped makes it so when air hits it, the air particles that go over the airfoil have to travel a longer distance than the particles that go under it. And since air particles must all move at the same speed, the air that goes over the air foil must move faster to keep up with the air that goes under it. This creates low pressure above the airfoiil which allows the high pressure beneath it to push it up. SO if the plane wasn't moving, there wouldn't be any air moving over the airfoil to lift the plane up, therefore making the treadmill useless.
Thank you for your time :-P
otherwise, we are arguing about whether planes need a runway at all to take off. as soon as the plane begins moving forward relative to the bystander, it is essentially using a runway, which we are trying to eliminate. please read my post on page 8 for your response from me.
i'll reiterate for those that don't care to.
THE ONLY THING WE ARE CONCERNED ABOUT IS WHETHER THE SURROUNDING AIR IS MOVING RELATIVE TO THE WING. THIS is what matters, this is an issue of relativity. not how fast the plane is moving relative to us, or relative to the treadmill. airflow creates the pressure gradient that allows for the lift. no airflow, no lift.
And yes, no airflow = no lift....
but can you provide any evidence as to why the treadmill would stop the jet from moving forward?
THATS the key, and the answer is nope.. you can't
all the wheels are doing in this example, is stopping the body of the jet hitting the tarmac.
and they are stopping the landing gear from becoming skids, dragging a huge trench in the runway
Last edited by Sk (2006-12-28 10:51:08)
Point taken heggs, It's a trick question the tread mill is to short to allow the plane to achieve take off speed
for most jets this is some where between 100 and 200 MPH, but the plane will move forward.
for most jets this is some where between 100 and 200 MPH, but the plane will move forward.
Are you saying that video proves a jet aircraft can take off a treadmill. Sorry I found it quite amusing that you think that can prove a point.Sk wrote:
PLEASE let this video be the end of it....
http://videos.streetfire.net/player.asp … BA1A43A06B
it would probably deal with a translation of the thrust to the angular velocity and angular acceleration of the wheels. some slew of equations that i would not like to have to try to solve. i think it could be done, just with many headaches.Sk wrote:
yes, you're right.. relative speed between plane and treadmill makes no difference.
And yes, no airflow = no lift....
but can you provide any evidence as to why the treadmill would stop the jet from moving forward?
THATS the key, and the answer is nope.. you can't
http://img300.imageshack.us/img300/2388 … offel5.gif
Remember Me As A Time Of Day
lol no.spray_and_pray wrote:
Are you saying that video proves a jet aircraft can take off a treadmill. Sorry I found it quite amusing that you think that can prove a point.Sk wrote:
PLEASE let this video be the end of it....
http://videos.streetfire.net/player.asp … BA1A43A06B
I'm using it to prove that the movement of the ground has little or no effect to the movement of a vehicle powered by the movement of air (or the differences in pressure of air)... which, although crudely, this goes a long way towards proving.
As you can CLEARLY see, the skateboard moves forward, irregardless of what speed it's wheels are doing.
Infact, at one point, he JANKS the paper and it makes bugger all difference
THAT is what I was posting the video to prove, which it does, which then goes along to show that a treadmill, acting soley on the wheels of a jet plane, will make next to no difference to the forward momentum of the plane.
indeed, but I'd be willing to bet that the overall drag factor calculated will not be even close to half the thrust factor generated by the propulsion system...heggs wrote:
it would probably deal with a translation of the thrust to the angular velocity and angular acceleration of the wheels. some slew of equations that i would not like to have to try to solve. i think it could be done, just with many headaches.Sk wrote:
yes, you're right.. relative speed between plane and treadmill makes no difference.
And yes, no airflow = no lift....
but can you provide any evidence as to why the treadmill would stop the jet from moving forward?
THATS the key, and the answer is nope.. you can't
http://img300.imageshack.us/img300/2388 … offel5.gif
of course... the forces acting on the wheel could eventually become so great that the rubber is torn from them, releasing the air, increasing the drag factor... and eventually leaving the plane to run on its uncarrige... which probably WOULD stop the plane
For the record, I am aware that this is not an original topic.
How about this one;
A treadmill is in a sealed box with a poison and a radioisotope
This is constructed so that within an hour, the isotope has an equal chance of decaying and thus energising a geiger counter which causes the release of poison which kills the treadmill. Without opening the box or otherwise looking into it and knowing the outcome, in what state does the treadmill exist after one hour?
How about this one;
A treadmill is in a sealed box with a poison and a radioisotope
This is constructed so that within an hour, the isotope has an equal chance of decaying and thus energising a geiger counter which causes the release of poison which kills the treadmill. Without opening the box or otherwise looking into it and knowing the outcome, in what state does the treadmill exist after one hour?
Last edited by ATG (2006-12-28 11:04:13)
actually, fuck it.
it can't be done because if you're using a treadmill as a runway, you're using a runway. plain and simple. friction is absolutely necessary, and the treadmill and wheel combo removes friction (in a perfect world). so, free spinning wheels on a treadmill are useless. the plane will still move forward. thanks for the visual sk.
it can't be done because if you're using a treadmill as a runway, you're using a runway. plain and simple. friction is absolutely necessary, and the treadmill and wheel combo removes friction (in a perfect world). so, free spinning wheels on a treadmill are useless. the plane will still move forward. thanks for the visual sk.
Remember Me As A Time Of Day
We need clarification from ATG on just how long this tread mill is, and remember as I stated earlier the speed of the tread mill will create moving air relative to the speed and direction of the tread mill.
I love spell check.
I love spell check.
OK here it is. Proof of the airplane on a treadmill.
http://video.google.com/videoplay?docid … &hl=en
http://video.google.com/videoplay?docid … &hl=en
It would have to be runway length, and no, there would not be handles to catch the wings.
then why have a treadmill at all? to start a long discussion that ends with that as an answer? a treadmill is fine, but a runway is cheaper.ATG wrote:
It would have to be runway length, and no, there would not be handles to catch the wings.
Remember Me As A Time Of Day
Viper loved the video, only wished you could have shown the air the tread mill was moving under the wings
that has nothing to do with the air the tradmill was moving, its negligeable.
A car on a treadmill would use the ground to move, and the ground would be moving too so the car would stand still.
A plane use the air to move, the air doesnt move, its stationary, so the plane moves, regardless of the movement of the ground, because the wheels are not required to move the plane forward...
A car on a treadmill would use the ground to move, and the ground would be moving too so the car would stand still.
A plane use the air to move, the air doesnt move, its stationary, so the plane moves, regardless of the movement of the ground, because the wheels are not required to move the plane forward...
you're getting all my karma for that... and for wearing Jamie's hat in the entire videoviper313 wrote:
OK here it is. Proof of the airplane on a treadmill.
http://video.google.com/videoplay?docid … &hl=en
Thanks for giving people a spot on example and proving our cause!
(my fingers were just about to fall off with all the typing!)
that really does not prove anything, the skateboards not on a treadmill which is moving as fast as it, and it doesnt have wings.....Sk wrote:
PLEASE let this video be the end of it....
http://videos.streetfire.net/player.asp … BA1A43A06B