This should generate some interesting responses...

I find it amusing the amount of seemly intelligent people, even within the aviation community still argue about this age old physics question.

"Imagine a 747 is sitting on a conveyor belt, as long and wide as a runway. The conveyor belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?"

It's like even though they should know better, they still can not get their head out of the automobile box.

Rug Rat (Brent Hendricks)
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Hello Rug!

24 Feb 26 20:23, you wrote to all:


So, you are basically saying the a/c is stationery at a fixed point on the ground - so there is no actual airflow (assuming it is in a closed area) so the
aircraft cannot attain T/O speed - hmm mind you there is no airspeed so it will
not go any where.


Well that my logic but there again I am a 79 year old (in June) pilot so what do I remember from the ATP/IR course of many years ago :(

Mind you physics does somewhat play a part....

Vince

This should generate some interesting responses...

I find it amusing the amount of seemly intelligent people, even within
the aviation community still argue about this age old physics
question.

"Imagine a 747 is sitting on a conveyor belt, as long and wide as a
runway. The conveyor belt is designed to exactly match the speed of
the wheels, moving in the opposite direction. Can the plane take off?"

It's like even though they should know better, they still can not get
their head out of the automobile box.

Rug Rat (Brent Hendricks)
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Vincent


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Don't fall for the familiarization bias trap..

You are mentally comparing an aircraft with a car or bicycle when you are assuming the belt and wheels will cancel each other out and stay in a fixed location.

This is try in land based modes of transportation because a car is propelled "thrust" by energy produced by the engine begeing transfered to the wheels, wheels spin, and friction between the wheels creating a force in the opposite direction of travel. So force applied to treadmill in same direction and speed of treadmill cancel each other out, so there is no force (Or thrust).

Now. Switch to the aircraft.

An aircraft, wheather propeller or jet, eneregry is created by the engines and transfered to the air around it, (We will use jet because it is easier to imagine the force). Jet sucks in air, blowing it out the back. Pushing on the outside air, in the opposite direction of travel. The wheels have NOTHING (Except for a minor friction value (and wheel bearing friction / heat) to do with it's motive force. NOTHING, they free spin. You apply throttle, the jet pushes on the air around the aircraft, propelling it forward. Wheels free spin, they have no part of the equation. Aircraft moves forward, creating apparent wind over the wings, creating lift. Aircraft takes off.

Human factors at its best....

Rug Rat (Brent Hendricks)
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This should generate some interesting responses...

I find it amusing the amount of seemly intelligent people, even within

>the aviation community still argue about this age old physics question.

"Imagine a 747 is sitting on a conveyor belt, as long and wide as a

>runway. The conveyor belt is designed to exactly match the speed of
>the wheels, moving in the opposite direction. Can the plane take off?"

It's like even though they should know better, they still can not

>get their head out of the automobile box.

It seems to me the obvious answer is that the plane's ability to take
off has nothing to do with the tires. They just keep the belly of the
plane off the ground. The thrust will push the plane forward no matter
what speed the tires are turning, although designing that conveyor belt
could be tricky.. B)

---
* SLMR Rob * Avoid morning breath... Get up at noon
* Origin: Capitol City Online (1:2320/105)

Aircraft moves forward, creating apparent wind over the
wings, creating lift. Aircraft takes off.

Get a good video-camera ... the crash will be headline news ...

--- DB4 - 20230201
* Origin: AVIATION ECHO HQ (2:292/854)

Hello Rug!

26 Feb 26 05:46, you wrote to me:

The oppoint is that as the a/c is NOT moving due to the belt working in the opposite direction - therefore the a/c is stationery compared to air flow and therefore airflow over wings is zero - so not going anywhere - well until there is a differential in which case - one broken a/c.

You are going to have to explain your logic in a stronger detail as so far my logic still looks like holding.


BUT I could be wrong :)

Don't fall for the familiarization bias trap..

You are mentally comparing an aircraft with a car or bicycle when you
are assuming the belt and wheels will cancel each other out and stay
in a fixed location.

This is try in land based modes of transportation because a car is
propelled "thrust" by energy produced by the engine begeing transfered
to the wheels, wheels spin, and friction between the wheels creating a
force in the opposite direction of travel. So force applied to
treadmill in same direction and speed of treadmill cancel each other
out, so there is no force (Or thrust).

Now. Switch to the aircraft.

An aircraft, wheather propeller or jet, eneregry is created by the
engines and transfered to the air around it, (We will use jet because
it is easier to imagine the force). Jet sucks in air, blowing it out
the back. Pushing on the outside air, in the opposite direction of
travel. The wheels have NOTHING (Except for a minor friction value
(and wheel bearing friction / heat) to do with it's motive force.
NOTHING, they free spin. You apply throttle, the jet pushes on the
air around the aircraft, propelling it forward. Wheels free spin,
they have no part of the equation. Aircraft moves forward, creating apparent wind over the wings, creating lift. Aircraft takes off.

Human factors at its best....

Rug Rat (Brent Hendricks)
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Vincent


--- Mageia Linux v9 X64/Mbse v1.1.7/GoldED+/LNX 1.1.5-b20240604
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On Thu 26-Feb-2026 5:57p, Ward Dossche@2:292/854.0 said to Rug Rat:

Aircraft moves forward, creating apparent wind over the
wings, creating lift. Aircraft takes off.

Get a good video-camera ... the crash will be headline news ...

There wouldn't be a crash, it would be a normal takeoff.

Rug Rat (Brent Hendricks)
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You are still in box created by the comparing it to a car.

The wheels on an airplane have nothing to do with propelling the aircraft forward. The motive force (Thrust) is provided by a completely seperate sorce (Propeller or jet). The wheels just freespin (Or are just along for the ride). Since they don't provide the force pushing it forward the belt is not acting against this force. Aircraft moves forward and will reach takeoff speed.

If you want to compare it to the car, since this is what hangs people up.

Let's do this experiement with the car.

Belt matches motive force caused by engine transfering power to the wheels and friction on between the tires and treadmill cancel each other out, car does not move...

With out changing anything. Acelleration force on the car or treadmill speed (Or those metal rollers on a speedometer calibration or smog check station).

Now get behind the car and push it.. What happens? The car will move, because you are applying a second force which will become additive to 2 other forces in opposition to each other. Lets assign this an arbitrary value of 2.

so say car moving forward is 60 treadmill is 60 60-60=0+2=2. You have a net positive force of 2.

Airplane. Wheels have ZERO motive force, but we will still assign them a speed value (You will see why in a second..)

SO everyting is at idle. treadmill is not moving, engine isn't providing thrust, tires are not spinning.

So we apply thrust so that number will go up exponentionally.

Tread mill and tires match their speed. increasing exponentionally, Your Cesna lets say has a Vr of 80kts. WHEELS 80 - Treadmill 80 = 0. However we are not done... Becaue like you pushing the car from behind with have the thrust value for the propeller of +80 0+80 still = 80 and you will take off. (That is the visual demonstration), because in the real world the wheel rotational speed would be twice as fast.

The aircraft will take off.

If STILL won't listen. There are plenty of Youtube videos on it.

https://www.youtube.com/results?search_query=airplane+treadmill+mythbusters

Rug Rat (Brent Hendricks)
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Hello Rug!

26 Feb 26 14:47, you wrote to me:


My comment where NOT related to a road vehicle what ever but an aircraft that depends on forward motion in combination with AIRFLOW over its surfaces i.e. wings.

By the very fact that the a/c is stationery in relation to airflow nothing is going to happen.


Stop comparing to a road vehicle - it is not the same what so ever.

You are still in box created by the comparing it to a car.

The wheels on an airplane have nothing to do with propelling the
aircraft forward. The motive force (Thrust) is provided by a
completely seperate sorce (Propeller or jet). The wheels just
freespin (Or are just along for the ride). Since they don't provide
the force pushing it forward the belt is not acting against this
force. Aircraft moves forward and will reach takeoff speed.

If you want to compare it to the car, since this is what hangs people
up.

Let's do this experiement with the car.

Belt matches motive force caused by engine transfering power to the
wheels and friction on between the tires and treadmill cancel each
other out, car does not move...

With out changing anything. Acelleration force on the car or
treadmill speed (Or those metal rollers on a speedometer calibration
or smog check station).

Now get behind the car and push it.. What happens? The car will move, because you are applying a second force which will become additive to
2 other forces in opposition to each other. Lets assign this an
arbitrary value of 2.

so say car moving forward is 60 treadmill is 60 60-60=0+2=2. You
have a net positive force of 2.

Airplane. Wheels have ZERO motive force, but we will still assign
them a speed value (You will see why in a second..)

SO everyting is at idle. treadmill is not moving, engine isn't
providing thrust, tires are not spinning.

So we apply thrust so that number will go up exponentionally.

Tread mill and tires match their speed. increasing exponentionally,
Your Cesna lets say has a Vr of 80kts. WHEELS 80 - Treadmill 80 = 0. However we are not done... Becaue like you pushing the car from behind
with have the thrust value for the propeller of +80 0+80 still = 80
and you will take off. (That is the visual demonstration), because in
the real world the wheel rotational speed would be twice as fast.

The aircraft will take off.

If STILL won't listen. There are plenty of Youtube videos on it.

https://www.youtube.com/results?search_query=airplane+treadmill+mythbu
sters

Rug Rat (Brent Hendricks)
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Vincent


--- Mageia Linux v9 X64/Mbse v1.1.7/GoldED+/LNX 1.1.5-b20240604
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But, there is no way, unless you push the question so far into hyperbole that the question invalidates itself as being outside the relm of possibility.

You could say, well we will remove the landing gear, so the aircraft is in direct contact with the belt and can not overcome friction. If you are allowed to do that, then I can put larger engines on it so it will overcome friction.

The fact of the matter is, it is impossible for the aircraft to NOT move forward, as the propeller or jet pushing air backwards will propell it foward. The weels WILL spin at x2 of the the belt, and the plane moves forward. If you speed up the belt, the just spin that much faster, but the plane will still move forward.

Again, you can what if this to the point of hyperbole, but it becomes so far fetched that you are just moving numbers to prove to me an elephant can hang off a cliff with its tail tied to a dasiy. When common sense will tell you that is impossible.

The plane will fly.

Rug Rat (Brent Hendricks)
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Get a good video-camera ... the crash will be headline news ...

There wouldn't be a crash, it would be a normal takeoff.

It would even be a major crash...but you need to think outside the box to get the concept: 2 unsynchronised modes of propulsion ... when one drops away at the time of lift-off the stresses on the airframe will be of such a magnitude that the aircraft disintegrates.

Engineering 101.

\%/@rd

--- DB4 - 20230201
* Origin: AVIATION ECHO HQ (2:292/854)

Anyways..

This is bringing anoter good human factor / CRM lesson into this.

Confirmation bias.

Bringing in unrelated or incorrect facts to try in prove your incorrect conclusion.

Confirmation bias.

It has been debated, it has been proven with physical tests that the plane will take off, but those unwilling to accept that, they bring in more and more incorrect assumptions, leading to unfavorable outcomes.

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Hey Rug, or is it Rat? 8-)

... it has been proven with physical tests that the
plane will take off, ...

Show me the proof ... 8-)

\%/@rd

--- DB4 - 20230201
* Origin: AVIATION ECHO HQ (2:292/854)