The "Plane on a Treadmill" Question - Page 17

Flint · 12-09-2006, 11:16 AM

Quote:

Originally Posted by MaggieL

It's very counterintuitive if the only wheeled vehicles you've ever been in moved by applying power to the wheels.

I don't think anyone in the history of this question has ever thought that the wheels are the source of propulsion for the plane. Also, I don't think anyone has ever thought that a plane can take off without air moving over the wings. The question is designed to get groups of people arguing about two completely different scenarios, and these non-points are inherent in the comparison between the two. Based on what you believe the question is stating as the premise (which isn't specified), there are two different outcomes. There is no "right" answer.

lumberjim · 12-09-2006, 11:18 AM

yes there is.

dude.

if the plane is going 100 mph, and the track of the treadmill is also going 100mph.....then the plans'e wheels are going 100 mph......but they have no effect on the plane's speed because they rotate

xoxoxoBruce · 12-09-2006, 11:31 AM

Uh, wheels = 200, Jim.

The question was written to lead people into the wrong logic, rather than discarding superfluous information. It is a trick question, but there still is one right answer..... and many wrong answers.

Flint · 12-09-2006, 11:34 AM

"forward speed" relative to what? Not stated.

Of course, in #3 the plane can slide into forward motion, but that isn't necessary unless in addition to #1. In #2 it just takes off.

lumberjim · 12-09-2006, 11:46 AM

Quote:

Originally Posted by xoxoxoBruce

Uh, wheels = 200, Jim.

The question was written to lead people into the wrong logic, rather than discarding superfluous information. It is a trick question, but there still is one right answer..... and many wrong answers.

rotating 200 mph, yes. moving 100 mph as the plane carries them

relative to the earth, flint, as everything is.

MaggieL · 12-09-2006, 12:23 PM

Quote:

Originally Posted by Flint

I don't think anyone in the history of this question has ever thought that the wheels are the source of propulsion for the plane.

Nor did I say that. I said that if you'd only been in powered-wheel vehicles the situation was counterintuitive.

Oh, by the way:

an airplane that generates some lift in an unorthdox way

wolf · 12-09-2006, 12:40 PM

Quote:

Originally Posted by Spexxvet

NOW the plane/treadmill debate is OVER!

This is the internet. It's not over until somebody says something about Hitler and you know it.

Oh, crap. I just blew my nomination for the Hall of Fame. Is a non-productive contribution to the thread still counted as a contribution?

lumberjim · 12-09-2006, 12:51 PM

wow, maggie. here's more

why aren't these designs being applied to other aircraft?

tw · 12-09-2006, 12:58 PM

Quote:

Originally Posted by lookout123

It's George Jr's fault...mental midget....seven seconds... top management... limbaugh disciples... no WMD...

George Jr is the observer? No wonder an accurate answer is not possible!

Spexxvet · 12-09-2006, 01:00 PM

Quote:

Originally Posted by wolf

This is the internet. It's not over until somebody says something about Hitler and you know it.

Oh, crap. I just blew my nomination for the Hall of Fame. Is a non-productive contribution to the thread still counted as a contribution?

And you mentioned Hitler in the same post! Double whammy.

tw · 12-09-2006, 01:11 PM

Quote:

Originally Posted by Flint

"forward speed" relative to what? Not stated.

The speed is obviously defined by this:

Quote:

When the plane's engines throttle up, it begins to move forward,

Again, a reference to the equations F=ma and v=at . Speed does not exist on its own. Speed is a relationship between two references. Force (the "F") defines those two refeneces. Engine creates a force between airplane and air. Therefore speed is also created / measured between airplane and air. "Forward speed" is defined by that phrase

Quote:

When the plane's engines throttle up, it begins to move forward,

Previously posted are the numbers to stick into those equations so that we know how long (t time) that engine (F force) must push the plane (m mass) to obtain minimum takeoff speed (v speed).

lumberjim · 12-09-2006, 01:14 PM

how fast would a standard jet have to turn it's engines in order to pull enough wind over its wings to generate lift? assuming it stood still relative to the ground?

glatt · 12-09-2006, 01:21 PM

They are mounted under the wing, so they couldn't do what you describe. The airflow has to be above the wing.

lumberjim · 12-09-2006, 01:30 PM

the air has to go faster above than below, so the engine position below the wing prevents that from ever happening. right on

MaggieL · 12-09-2006, 02:14 PM

Quote:

Originally Posted by lumberjim

why aren't these designs being applied to other aircraft?

Well...it looks gooofy, and aviators can be surprisingly conservative. The engineering of it is tricky...I suspect the wing shape has a weight penalty. And once you're airborne there's usually plenty of lift available, as long as you're willing to trade it for induced drag.

It's a rockin' performer on takeoff, but I bet the efficiency blows dead goats in cruise. Nonetheless, Custer apparently sued Fairchild claiming the A-10 Warthog violated his patent.

By the way, The MidAtlantic Air Museum at the Reading Airport has a Channelwing...not currently flyable.

12-09-2006, 11:18 AM	#242
lumberjim I can hear my ears Join Date: Oct 2003 Posts: 25,571	yes there is. dude. if the plane is going 100 mph, and the track of the treadmill is also going 100mph.....then the plans'e wheels are going 100 mph......but they have no effect on the plane's speed because they rotate __________________ This body holding me reminds me of my own mortality Embrace this moment, remember We are eternal, all this pain is an illusion ~MJKeenan

12-09-2006, 11:31 AM	#243
xoxoxoBruce The future is unwritten Join Date: Oct 2002 Posts: 71,105	Uh, wheels = 200, Jim. The question was written to lead people into the wrong logic, rather than discarding superfluous information. It is a trick question, but there still is one right answer..... and many wrong answers. __________________ The descent of man ~ Nixon, Friedman, Reagan, Trump.

12-09-2006, 11:34 AM	#244
Flint Snowflake Join Date: Mar 2006 Location: Dystopia Posts: 13,136	"forward speed" relative to what? Not stated. Of course, in #3 the plane can slide into forward motion, but that isn't necessary unless in addition to #1. In #2 it just takes off. __________________ **************** There's a level of facility that everyone needs to accomplish, and from there it's a matter of deciding for yourself how important ultra-facility is to your expression. ... I found, like Joseph Campbell said, if you just follow whatever gives you a little joy or excitement or awe, then you're on the right track. . . . . . . . . . . . . . . . . . . . . . . . . . . Terry Bozzio**

12-09-2006, 12:51 PM	#248
lumberjim I can hear my ears Join Date: Oct 2003 Posts: 25,571	wow, maggie. here's more why aren't these designs being applied to other aircraft? __________________ This body holding me reminds me of my own mortality Embrace this moment, remember We are eternal, all this pain is an illusion ~MJKeenan

12-09-2006, 01:14 PM	#252
lumberjim I can hear my ears Join Date: Oct 2003 Posts: 25,571	how fast would a standard jet have to turn it's engines in order to pull enough wind over its wings to generate lift? assuming it stood still relative to the ground? __________________ This body holding me reminds me of my own mortality Embrace this moment, remember We are eternal, all this pain is an illusion ~MJKeenan

12-09-2006, 01:21 PM	#253
glatt ™ Join Date: Jul 2003 Location: Arlington, VA Posts: 27,717	They are mounted under the wing, so they couldn't do what you describe. The airflow has to be above the wing.

12-09-2006, 01:30 PM	#254
lumberjim I can hear my ears Join Date: Oct 2003 Posts: 25,571	the air has to go faster above than below, so the engine position below the wing prevents that from ever happening. right on __________________ This body holding me reminds me of my own mortality Embrace this moment, remember We are eternal, all this pain is an illusion ~MJKeenan

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