what if the treadmill was signed by Coach Ditka?


[Edited on December 13, 2007 at 9:03 PM. Reason : 10 pages of craziness.]

12/13/2007 9:03:24 PM

Quote :

"you offered no evidence to support your claim. (it will take off, im with you on that) admit it, you just posted so you could say you are a "rocket scientist" tool"

true, I do like saying "I'm a Rocket Scientist", and yes, I am a tool, but I didn't need to give any evidence b/c all the evidence is already in this thread over and over again. Propulsion for aircraft comes from pressure differences trying to reach equilibrum. Wheels for aircraft are free rotating (save for the brakes), and so the limiting factor of the aircraft takeoff are the engines. An aircraft will take off at the same IAS no matter the head/tail wind, and in either case, the ground speed could be very different.

the damn plane takes off people.

12/13/2007 9:18:24 PM

I flew to Chicago this morning, and this thread was on my mind. I waited on the plane until everyone had gotten off, and then I went and asked the pilots what they thought.

The captain said there was no way in hell the plane would take off, and the first officer thought that it would

12/14/2007 3:34:19 PM

bttt

12/19/2007 11:32:00 AM

Quote :

"Wheels for aircraft are free rotating (save for the brakes), and so the limiting factor of the aircraft takeoff are the engines"

and if everything was frictionless the aircraft would not move at all due to the belt (with engines off)

with the engines on, it's pushed forward with the wheels spinning 2x the speed of the relative ground position, until it achieves enough airflow over the wings and body to generate enough lift to take off.

12/19/2007 11:37:48 AM

if the plane is not going anywhere...how does it generate lift from zero wind? isnt lift created when air travels over a wing? such as

12/19/2007 11:50:08 AM

go back and read 10 pages of this thread.

12/19/2007 11:51:11 AM

AIRPLANES ARE POWERED BY WITCHCRAFT AND SOUND WAVES. THE TREADMILL IS IRRELEVANT UNLESS IT HAS BEEN BLESSED BY A PRIEST.

12/19/2007 11:54:24 AM

12/19/2007 11:57:00 AM

Quote :

"(with engines off)"

please for the love of god read and understand this... inertia, very very simple

with the engines ON it will take off with no problems (other than wheel bearings that might burn out or tires that get destroyed

12/19/2007 12:01:17 PM

Quote :

"how does it generate lift from zero wind?"

What part of the the treadmill is causing no fluid flow over the wings?

12/19/2007 2:15:51 PM

this has nothing to do with fluids. the airplane is taking off from the ground, not from a lake, dumbass!

12/19/2007 2:20:37 PM

haha i love this thread.

12/19/2007 2:32:22 PM

^ me too! Whoever started this should get a prize for amusing so many

12/19/2007 2:37:02 PM

last years thread was even better.

i think it was longer than 10 pages

but i cant find it

12/19/2007 2:39:05 PM

asked a couple of piolets on my trip

1 said no, then when i got off he said yes. Other had no clue. And another said that if the speed of the wind against the plane was 132 knots or greater it didn't matter, it would take off

interesting

[Edited on December 30, 2007 at 5:44 PM. Reason : i know i cant spell]

12/30/2007 5:38:21 PM

Quote :

"then when i got off he said yes"

12/30/2007 5:40:56 PM

haha if you say it phonetically it does sound like pi-o-lets

12/30/2007 5:41:31 PM

it's worth repeating that people are arguing two slightly different situations.

12/30/2007 5:41:45 PM

are there any snakes on this plane?

12/30/2007 5:46:43 PM

yeah how heavy is the plane? if its made out of lead it wont fly as easy...would require more upward lift from the wings...might have to travel at say 1000mph to get enough lift

12/30/2007 5:53:10 PM

what the fuck does that have to do with anything

12/30/2007 5:56:34 PM

seriously people. ignore the wheels completely. they make no difference. It's like asking "can a plane fly at its takeoff speed above a horizontal conveyor belt which is traveling at the plane's takeoff speed in the opposite direction?" Of course the plane can fly, durr

12/30/2007 6:10:32 PM

ignore the wheels and focus on the weight...this thing is built out of lead and its NOT flying...

12/30/2007 6:12:09 PM

anyone wanna gamble against me and place a bet that it won't fly?

12/30/2007 6:15:13 PM

if the wheels break and the plane does a noseplant or something, then I guess it wouldn't take off

before that happened though, if the treadmill could match the forward force of the engines with equal force against the wheels in the opposite direction without the wheels breaking completely off, I think you'd see the plane kind of bounce forwards down the runway, until it could take off, since the wheels turning would be bound to generate some kind of force downward against the treadmill that got larger the faster they turned.

also, i guess the momentous speed of the treadmill would likely generate airflow against the plane, at least very near to the ground. that's just going to help the plane.

[Edited on December 30, 2007 at 6:20 PM. Reason : treadmill generates airflow idea]

12/30/2007 6:16:47 PM

the airflow generated by the treadmill would be negligable.

12/30/2007 6:22:11 PM

any airflow at all, however, will just help the plane, and god knows how fast the treadmill would be turning when the plane took off

of course it's been a while since i looked at the original idea, the treadmill is just matching speed with the plane, not speeding up enough so that the force on the wheels is enough at any time to keep the plane stationary, which makes it a ridiculous scenario, since the wheels could easily spin at 2x takeoff speed, which is all that would be required.

I think it's more interesting if you make it more challenging by saying that the wheels are invincible and the treadmill will go as fast as it should take to keep the plane stationary (assuming it stays on the ground). I think the plane will still take off though, even in the more difficult scenario.

[Edited on December 30, 2007 at 6:36 PM. Reason : oh yeah]

12/30/2007 6:24:48 PM

Forward momentum in an airplane is not generated by the friction of the wheels with the ground (like a car), so it doesn't even matter what the ground is doing or if there is any ground...

It would be similar to putting your car in neutral and setting it on a level treadmill... the car wouldn't go anywhere because the wheels spin independently of the drive, therefore the treadmill would not be moving the car (similar to it not moving the airplane)...

12/30/2007 6:37:05 PM

that's been covered, but since the wheels aren't frictionless, the airplane would have some backwards force against it, and the car would go backwards, since it's just in neutral.

also, since according to the original post, the scenario begins with the plane traveling at takeoff speed, it's either going to take off at t=0 or right after, aided by the downward force generated by the wheels spinning so fast.

[Edited on December 30, 2007 at 6:45 PM. Reason : .]

12/30/2007 6:40:37 PM

Quote :

"aided by the downward force generated by the wheels spinning so fast. "

since when do wheels spinning fast produce downforce?

12/30/2007 6:48:39 PM

since the leading edge of the wheel is moving down to meet the ground

[Edited on December 30, 2007 at 7:01 PM. Reason : i guess as long as they are spinning and touching the ground]

i guess i mean upforce, technically. some force pushing the plane away from the ground.

[Edited on December 30, 2007 at 7:05 PM. Reason : upforce]

12/30/2007 7:00:05 PM

AIRPLANE ON A CONVEYOR!

Toward the end of the month the TV show “Mythbusters” is going to handle the question of the airplane on the conveyor belt. The question is simple. If you put an airplane at the end of a 3000-foot long 50-foot wide conveyor belt, and if the conveyor belt runs backwards as the airplane is trying to take off, will the airplane ever make it into the air?

The answer is yes. STOP RIGHT NOW! NO EMAILS! The airplane will take off no matter how fast that conveyor belt turns. Those of you who have been calling me everything but a Child of God because I think that the airplane is going to take off are going to be mightily embarrassed.

Why bring this up? Because finally I get an email from someone who seems to know what they’re talking about. Here you go:

Quote :

"Subject: airplane on a tredmill/conveyer belt Name: TIM GEORGE Email: BUSYTIM@xxxxxxxx.NET Message: When I first heard you posit the question I said no, then as thought about it through the day I said yes. I do not fly full size planes, I fly rc planes. This allows me to power planes faster than a human could fly them, sometimes even the human with the rc transmitter. And yes what would be a fatal crash for humans, is often fixed by a bit of glue. Anyway, the airspeed on the plane is controlled by the prop, or air screw, you could actually set your conveyor belt faster that the plane is going and the plane would rotate, simply because the runway is a non factor. In fact, such runway could be helpful, it's possible that they would assist in shorter landings, as that is when wheels are an issue. just reverse it. I enjoy the show a lot. Tim"

You got it right, Tim. Congratulations.

[Edited on January 15, 2008 at 6:40 PM. Reason : Mr Boortz, Neal, 1 ea.]

1/15/2008 6:39:32 PM

i asked a NCSU physics proff this on sunday. He said yes

1/15/2008 6:47:07 PM

cessna = 60mph take off speed
wind = 75 headwind
no engine needed

wind = 75 mph tail wind
x2 ground speed needed to lift off = 120 mph

air flow over the wings is the issue here.

catapult's have been around since WWI and work just fine.
why reinvent the launch system.

so plane lands on a treadmill...

1/15/2008 7:11:47 PM

haha. this argument is still going on?

1/15/2008 7:32:24 PM

Quote :

"Because finally I get an email from someone who seems to know what they’re talking about. "

wtf are you talking about you "finally have heard from someone who knows what they are talking about." Only myself and about 20 other people said that exact same thing in this thread and however many other threads on this subject. It doesn't take a rocket scientist to figure out that the plane will take off, and I should know, I am one.

1/15/2008 7:34:54 PM

^ Calm down E-fighter... It's a copy and paste job for a source that does not (as far as I know) frequent TWW, therefore, they wouldn't know you were "one".

1/15/2008 8:13:09 PM

its really a bad question

if the plane is tethered so its stationary then hell no. you have to move forward to have wind over the wings.

if its not then what the wheels are doing means nothing. it will take off.

1/15/2008 9:07:48 PM

Quote :

"you have to move forward to have wind over the wings. "

wind has to move over the wings with enough force to create lift - how you accomplish that is up to you.

1/15/2008 11:44:04 PM

mythbusters is the real answer

1/17/2008 9:26:00 AM

when does this episode come on?

1/17/2008 9:29:14 AM

Quote :

"if the plane is tethered so its stationary then hell no. "

why would the plane be tethered? I read nothing in the problem that would hint at it being tethered.

1/17/2008 9:31:44 AM

isnt the idea of a treadmill to keep the object on it stationary?

1/17/2008 9:37:11 AM

the whole idea of the treadmill is to throw people off. the question is set up to make people think that the airplane will be stationary, but when they actually put some thought into the question, it is obvious that the treadmill has no more than a negligible effect. (zero effect in that wonderful frictionless world we all lived in during high school physics.)

1/17/2008 9:41:35 AM

bttt, according to Mythbusters last night, they will be doing this next week.

1/24/2008 9:47:55 AM

finally

1/24/2008 9:50:22 AM

for those starting to argue semantics, im pretty sure "take off" means flight, and of course it will not fly.
0 displacement.
0 flow over wings. (or close to it, whatever airflow is produced by the movement of the treadmill will clearly not be enough for the pressure difference required. for takeoff.)

mythbusters is an interesting show, but in the case of several of the "myths" (especially when fluid mechanics is involved...) well, they dont know jack. see the one where they both predicted a truck would have better gas mileage with the tailgate down. ROFL.

1/24/2008 9:59:08 AM

I can't believe university students or alumni would keep a thread like this going with debates.

1/24/2008 10:03:11 AM

i bet you dont even own a truck

1/24/2008 10:04:22 AM