Can a Plane on a Treadmill Take Off?

Tony wrote:
176. cjcampbell
Feb 6, 9:41 pm show options

Newsgroups: rec.aviation.student, rec.aviation.piloting
From: "cjcampbell" - Find messages by
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Date: 6 Feb 2006 18:41:35 -0800
Local: Mon, Feb 6 2006 9:41 pm
Subject: Can a Plane on a Treadmill Take Off?
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"cjcampbell" wrote

Okay, I see why the plane moves forward normally no matter how fast the
treadmill is going and even why it would not work in an automobile.

Well, not exactly. This dead horse is fun to beat. Suppose I tell you
the car is going forward at 60 mph. That means the belt is going the
other way at 60, right? The speedometer would be indicating 120.

The OP said the belt is moving backward as fast as the whatever is
moving forward. When you substitute real numbers into the thing it
becomes more clear.

Or not.

Apparently not to everyone. :-)

The speedometer would indicate 60.

If the car had an airspeed indicator it would, I agree, indicate 60. In
the model I suggested the car is moving to the north at 60, the
treadmill to the south at 60, and the speedometer will indicate 120.

Uh-Oh!!.....here we go again!

I vote -- 120
Kinda like an escalator. You can still go up on a "down" escalator
if you run. The treadmill would have to be "set" at the 60 mph speed
so that the car's "input" would not affect it. Then you could move
faster "forward" than the treadmill is moving "backwards". You could
also adjust the indicated speed to less than 60 and the conveyor would
carry the car backwards at less than 60. All relative to the world.
Speedometer says 60 - car is standing still.
Speedometer says 120 - car moves forward 60 mph
Speedometer says 0 - car moves backwards 60 mph

The conveyor is just another stationary road in a different reference frame.
Only this time it's not interacting with another frame's stuff (airmass).
The conveyor could be on another planet....or BE another planet.

"cjcampbell" wrote in message
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Tony wrote:
176. cjcampbell
Feb 6, 9:41 pm show options

Newsgroups: rec.aviation.student, rec.aviation.piloting
From: "cjcampbell" - Find messages by
this author
Date: 6 Feb 2006 18:41:35 -0800
Local: Mon, Feb 6 2006 9:41 pm
Subject: Can a Plane on a Treadmill Take Off?
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"cjcampbell" wrote

Okay, I see why the plane moves forward normally no matter how fast the
treadmill is going and even why it would not work in an automobile.

Well, not exactly. This dead horse is fun to beat. Suppose I tell you
the car is going forward at 60 mph. That means the belt is going the
other way at 60, right? The speedometer would be indicating 120.

The OP said the belt is moving backward as fast as the whatever is
moving forward. When you substitute real numbers into the thing it
becomes more clear.

Or not.

Apparently not to everyone. :-)

The speedometer would indicate 60.

The conveyor is just another stationary road in a different reference frame.

....but an airplane's "reference frame" is ALWAYS the
surrounding/relative air, not the runway beneath it!

The Monk

"Flyingmonk" wrote in message
oups.com...
The conveyor is just another stationary road in a different reference
frame.

...but an airplane's "reference frame" is ALWAYS the
surrounding/relative air, not the runway beneath it!

The Monk


Exactly,....that's why the airplane will take off.
Tony brought up the prospect of replacing the airplane
with a car.

"muff528" wrote:

Uh-Oh!!.....here we go again!

I vote -- 120
Kinda like an escalator. You can still go up on a "down" escalator
if you run. The treadmill would have to be "set" at the 60 mph speed
so that the car's "input" would not affect it.
But that would change the problem. In the problem as stated, you would
have to have a device that determined the cars forward speed (NOT its
wheel speed) and feed that input to the speed regulator on the
treadmill.

--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

A plane on a conveyor belt takes off East Bound at 9:15am from Peoria,
Il, while a 747 on a conveyor belt takes off West Bound at the same
time from Hackensack NJ.
What time and at what point will they meet?

NEVER you morons. There is no air moving over the wings to produce any
'lift', much less any forward ground speed. I can't believe the
stupid crap that people talk about here.

Alexy,

The conveyor is programmed to move in such a way as to maintain the
aircraft at an airspeed of zero as measured at the pitot.

Absolutely, if you CHANGED the problem, and restated it as above, then
it wouldn't fly.


Actually, you couldn't do that - which is another point the question
makes.

--
Thomas Borchert (EDDH)

Actually conveyor belt would decrease the length of runways if operated
in the direction of take off???

Actually conveyor belt would decrease the length of runways if operated
in the direction of take off???

Instead of wasting all that energy to power the conveyor belt, why not
add that power to the plane itself?

The Monk