A jet plane on a large treadmill

**Ted Striker** · 04-14-2012, 10:46 AM

^^^ I don't even know what you just said, but I agree that this is entertaining in a perverse sort of way.

**GeezerSteve** · 04-14-2012, 10:48 AM

Big Snowballs, pack me a bowl dood

**Arno** · 04-14-2012, 10:51 AM

Originally Posted by f2f

That pilot thought he wouldn't take off? Wtf???

**Big Snowballs** · 04-14-2012, 10:51 AM

Originally Posted by Big Snowballs

Don't like whats been repeated, stated, explained then don't look, don't post.

I just did what I was arguing against and barked orders.... my bad !!!

**Ted Striker** · 04-14-2012, 10:55 AM

Originally Posted by Skirotica

Remember the words of the OP

"this conveyor has a control system that tracks the planes speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction)."

We are talking hypotheticals here. We aren't applying forces up the landing gear and all that. We simply turn a belt in the opposite direction at exactly the right speed needed to negate what would be the acceleration of the aircraft.

You take friction coefficients and belt transmissions out of the equation because it's all hypothetical. The plane starts to move forward. It's first couple of feet are positive then the belt kicks in and suddenly the wheels are spinning in place covering ever more belt but the belt keeps coming because it is somehow moving super fast.
There are unpowered treadmills that will do this to a limited extent. Eventually though you can overpower the free spin capability of the unpowered treadmill. This hypothetical assumes you can never overpower the treadmill. That's the rule set by the OP. play in his world or create your own.

DBS has the correct answer.

Originally Posted by doughboyshredder

You are interpreting the question incorrectly. Which, btw, is the biggest problem in this entire thread. You are thinking that the treadmill is matching the wheel speed. It is not in the OP's question. It is matching the planes speed. So, when the plane is doing 10mph, the treadmill is doing 10mph, and the wheels are spinning at 20mph. As the plane accelerates, the treadmill matches that acceleration, and the wheels double that acceleration. The plane takes off.

**Ted Striker** · 04-14-2012, 10:57 AM

Originally Posted by Arno

That pilot thought he wouldn't take off? Wtf???

Well, he is flying an ultralight... how smart can he be?

**Big Snowballs** · 04-14-2012, 11:03 AM

Originally Posted by Big Steve

Big Snowballs, pack me a bowl dood

Forsure !
Great idea... time to get airborne !

**f2f** · 04-14-2012, 11:48 AM

Originally Posted by Arno

That pilot thought he wouldn't take off? Wtf???

most likely scripted, in my opinion. they needed at least one less-than-perspicacious opinion.

**stuckathuntermtn** · 04-14-2012, 12:44 PM

Originally Posted by f2f

All that's doing is over powering the conveyor belt.

**Jethro** · 04-14-2012, 01:54 PM

Stuck, the wheels are a low friction interface between the plane and the conveyor. The plane will go forward regardless of the conveyor speed. You know the trick where a waiter yanks the table cloth out from under the dishes? think of the conveyor as the sheet. It does not affect the plane.

**f2f** · 04-14-2012, 03:32 PM

"That Professor Goddard with his 'chair' in Clark College and the countenancing of the Smithsonian Institution does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react--to say that would be absurd. Of course, he only seems to lack the knowledge ladled out daily in high schools."

**monkeypunch** · 04-15-2012, 05:09 PM

Originally Posted by commonlaw

Quoting for future hilarity.

It's funny because he is angry.... angry and wrong.

**LongShortLong** · 04-16-2012, 12:04 PM

Originally Posted by focus

y'all are idiots. There's like 3 or 4 people who've posted in this thread who "get it," everybody else is just ridiculous -- whether they believe the plane takes off or not.

This thread shows why life as an engineer sucks. The world is filled with idiots* who don't understand how stuff works. And yet, your job is to keep them safe in their systems they don't even understand. As this thread shows, it's nearly pointless to argue with the idiots because very few will understand.

* idiots sometimes includes engineers, and me.

**cliffhucker** · 04-16-2012, 04:34 PM

It has nothing to do with how much thrust there is, if there is not air moving across and under the wings at a sufficient enough speed it wont have any lift. It could go 2000mph on a treadmill and not take off because there is no lift provided from the wings...

**jfost** · 04-16-2012, 04:48 PM

Originally Posted by cliffhucker

It has nothing to do with how much thrust there is, if there is not air moving across and under the wings at a sufficient enough speed it wont have any lift. It could go 2000mph on a treadmill and not take off because there is no lift provided from the wings...

did you not watch the video?

did you not read the thread?

**Ted Striker** · 04-16-2012, 04:52 PM

````````

**guroo270** · 11-18-2012, 08:14 AM

I just asked this question to a million people. We'll see what happens.

**guroo270** · 11-18-2012, 08:42 AM

first caller got it. Now I'm waiting for the debate.

**jfost** · 11-19-2012, 01:04 AM

your SuperPAC has 1000000 members?

**guroo270** · 11-19-2012, 07:21 AM

I work in radio. I was surprised, there was no debate. It was riddle day, even though this isn't a riddle really, I posed the question. TGR is the best. I get lots of stuff from here and put it on the air.