Riddle Me This.........

[DOC]

Originally Posted by Casper

how can a conveyor counteract thrust? It cant. The plane does not drive forward from the wheels. The wheels are not the force driving forward. .

no, it woudl be 200 + 200 = 400. That how fast the wheels would be turning. The plane would still be doing 200kph.. and take off. The convayor cant stop this, all it can do is make the wheels turn faster. The wheels are freespinning, the convayors actual force on the axles (and therefore the actual body of the plane) is 0.

Now im confused if the wheels are not the driving force then they must run at the same speed as the treadmill

they would simple roll at the same speed in the oppsite direction

[42.57lb]

Originally Posted by flappist

No 200km/h minus (not plus they are in opposite directions) -200km/h = 400km/h, the speed of the wheels.

The axels of the conveyor rollers are going 0km/h,
The air is going 0 km/h
The roller is going 200 km/h -->
The plane 200km/h <--
Wheels 400km/h

V1, rotate, gear up, trim for best climb, "Traffic Loony CTAF, Alpha Foxtrot Foxtrot, bugsmasher has departed 39, on climb to any altitude and turning onto any heeading away from here, traffic Loony CTAF"

Ok, so if the plane is moving the acels aren't moving? why minus? they are opposite, that's why one is in the positive direction the other is in teh negative direction.

[42.57lb]

Originally Posted by Casper

how can a conveyor counteract thrust? It cant.

I agree the frictional force is what does the counteracting.

[Casper]

Originally Posted by DOC

Now im confused if the wheels are not the driving force then they must run at the same speed as the treadmill

they would simple roll at the same speed in the oppsite direction

Very close. The plane would move forward as normal, the wheels would travel at the speed of the plane + the speed of the conveyor. Basically, the wheels would spin twice as fast as the actual true aircraft speed.

[Charliewool]

Flappist... I'm with you.....Vanuatu James!... And lets rid ourselves of the treadmill of life

[flappist]

Originally Posted by 42.57lb

Ok, so if the plane is moving the acels aren't moving? why minus? they are opposite, that's why one is in the positive direction the other is in teh negative direction.

FFS are you for real....

Do you undestand that there is no power to the wheel and they do not spin in the air?

The conveyor CANNOT compensate for the plane it does have anything to push against....

[Casper]

Originally Posted by 42.57lb

I agree the frictional force is what does the counteracting.

friction may be some form of counteracting but it is miniscule. Basically no more than the friction force from the wheels turning on a normal runway. Certainly no where near enough to stop the plane taking off.

[42.57lb]

My position (and I am very very tired) is that IF the pane's wheels were not part of the system and they produced NO friction the plane would have no probelm taking off. However as stated by the RULES of the problem that they are a part of the system.

This has been most stimulating.

I'm putting it to the great physicists and if they correct me I will henceforth post my most sincere apologies.

It's been fun

[Captain Stubing]

Airplane engine starts, pilot accelerates, causing wind to move through the props, the wheels turn with the belt. Propeller goes full throttle, causing acceleration through the air, wheels are rolling, on a runway that is moving at an equal speed against it... Hang on... where's the airflow to create the lift?


Naah... I've got to give it up for the night, but.... The Bugga Aint Flyin' Tonight!

[DOC]

Originally Posted by Casper

Very close. The plane would move forward as normal, the wheels would travel at the speed of the plane + the speed of the conveyor. Basically, the wheels would spin twice as fast as the actual true aircraft speed.

I'm Changing airlines, i dont know if were flying or gounded any more : its easy to tell the summer months are here and there's didly on the tube, i thinks im going to go and start playing with the motor in a certain xr8 and see how fast i can get that to fly down the qtr in january, been fun

:

[flappist]

Originally Posted by swanny

Airplane engine starts, pilot accelerates, causing wind to move through the props, the wheels turn with the belt. Propeller goes full throttle, causing acceleration through the air, wheels are rolling, on a runway that is moving at an equal speed against it... Hang on... where's the airflow to create the lift?


Naah... I've got to give it up for the night, but.... The Bugga Aint Flyin' Tonight!

WHAT BELT, the conveyor belt?

What has that got to do with it?

[Casper]

Originally Posted by 42.57lb

My position (and I am very very tired) is that IF the pane's wheels were not part of the system and they produced NO friction the plane would have no probelm taking off. However as stated by the RULES of the problem that they are a part of the system.

This has been most stimulating.

I'm putting it to the great physicists and if they correct me I will henceforth post my most sincere apologies.

It's been fun

then no plane with wheels can ever take off. Too much wheel friction. I'll let the airforce know asap.

[Ghiadude]

Originally Posted by 42.57lb

My position (and I am very very tired) is that IF the pane's wheels were not part of the system and they produced NO friction the plane would have no probelm taking off. However as stated by the RULES of the problem that they are a part of the system.

This has been most stimulating.

I'm putting it to the great physicists and if they correct me I will henceforth post my most sincere apologies.

It's been fun

goodnight...

[Charliewool]

(I still reckon big pete should be lynched for this!)

[42.57lb]

Originally Posted by Casper

then no plane with wheels can ever take off. Too much wheel friction. I'll let the airforce know asap.

just tell them to get rid of all those run ways that ACCELERATE AT THE SAME RATE AS THE PLANES BUT IN THE OPPOSITE DIRECTION ;) hehehehe.

otherwise, I'nm sure they'll be fine.

[cArSiK]

If this plane DID take off - at the moment of takeoff when the wheels left the belt , what speed would the aircraft be moving?

[Ghiadude]

ladies and gentleman this is your captain speakin... due to the laws of physics we will not be taking off this evening due to a treadmill under the wheels... plse dissembark the plane in an orderly fashion we apologise and thank you for flying treadmill airways

[Casper]

Originally Posted by 42.57lb

just tell them to get rid of all those run ways that ACCELERATE AT THE SAME RATE AS THE PLANES BUT IN THE OPPOSITE DIRECTION ;) hehehehe.

otherwise, I'nm sure they'll be fine.

if moving runways are bad then I'll let the US navy know that the need to scrap the aircraft carriers.

[Casper]

Originally Posted by cArSiK

If this plane DID take off - at the moment of takeoff when the wheels left the belt , what speed would the aircraft be moving?

same speed it does every other time it takes off.

[Charliewool]

Originally Posted by cArSiK

If this plane DID take off - at the moment of takeoff when the wheels left the belt , what speed would the aircraft be moving?

ing FAST!... (stop complicating things!) out:

[flappist]

Originally Posted by 42.57lb

My position (and I am very very tired) is that IF the pane's wheels were not part of the system and they produced NO friction the plane would have no probelm taking off. However as stated by the RULES of the problem that they are a part of the system.

This has been most stimulating.

I'm putting it to the great physicists and if they correct me I will henceforth post my most sincere apologies.

It's been fun

Are you sure you don't work for the Liberal Party.....

You have just contridicted everything you have stated before.

Amazing, you make John Howard look like an amateur........

[Casper]

Right.. wheres big pete? I got a little modding to do on his head :

[Charliewool]

Originally Posted by flappist

Are you sure you don't work for the Liberal Party.....

You have just contridicted everything you have stated before.

Amazing, you make John Howard look like an amateur........

Totally taken out of context!.. The media :baby bott and you people have completely misrepresented my earlier comments, READ my LIPS will you! :

[Charliewool]

To have 338 posts & over 2500 views in under 14hrs on ONE hair-brain topic, Must be some sorta record on here?... AMAZING

[flappist]

I'm going to put this on PPRUNE

[THORNSPAWN]

This still going OMFG!!
The plane took off long ago.
Here's another one:
Let's say a planes wheels had enough friction to have any impact at all on the planes
ability to take off, say the engines had enough power to move the plane at say 400kph
on a stationary runway, due to the wheelspeed of 400kph, then assuming it
was on a conveyor turning backwards at 200kph it would still have enough power to
overcome the friction to be able to accelerate to 200kph relative to the surroundings
or 400kph relative to the conveyor.
But since friction is negligable any arguements about friction between the wheels
and the ground\conveyor are pointless and irrelevent.

Another one:
Some seem to think the plane will be stationary, hence the no air-flow arguements,
but with the conveyor moving at a billion miles an hour in the other direction.
The conveyor moves at a speed relative to the plane itself, if the plane was stationary
the conveyor would be stationary because the plane is not moving, it
wouldn't have started in the first place. The conveyor only starts when the
plane starts moving relative to it's surroundings, not the conveyor, as the
plane speeds up the conveyor speeds up however the plane is still
accellerating relative to it's surroundings including the air which, of course,
when moving over the wings creates lift = take off.

Another one:
With the conveyor moving at 200, the plane moving in the opposite direction
at 200 the wheels will be doing 400 and, now here's the big one, the air,
assuming it is still, will be doing 200 in the opposite direction relative to the
conveyor seing as the conveyor is also moving through the air, albeit along
the ground, and 200 relative to the plane also in the opposite direction.
Once again airspeed over the wings creates lift = take off


P.S. I appologise for not being smart enough to be able to dumb it down any further.

[Rodp]

I still maintain that the skateboard on the conveyor is a great analogy.

...and for those who think that the plane won't take off, consider this.

Gender indeterminant (damn the PC world) person standing on a skateboard that is glued to their feet and that skateboard is on a treadmill. Gender indeterminant person is holding onto a rope. That rope is securely attached to an elephant. Elephant moves forward. Treadmill matches the speed of the wheels of the skateboard.

Now, those who suggest that the plane won't move will have to conceed that someone standing on a skateboard that's sitting on a speed matched treadmill will be able to stop an elephant from moving with no effort on their part at all...? Regardless of how hard this elephant pulls, the treadmill counteracting the speed of the wheels of the skateboard will stop an elephant dead in its tracks? Sounds silly, yes?

So in the case of the elephant pulling a skateboarder, the driving force isn't the skateboard, it's the elephant. The wheels have zero to do with the forces being applied on gender indeterminant.

[fauxpas]

omg, you guys are dumber than a bag of hammers...

[TheSneakiness]

This still going?

FFS people, get over it. It's not number one priorty in your lives at this moment.

[the_scotsman]

Its a bloody tragedy that some of these guys can't get it into their heads that the plane would take off !