MEIGNORANT

That experiment the Mythbusters ran doesn't even come close to replicating the original problem. Their expensive experiment was a waste of time. Whether or not the plane can build up enough air around its wings to actually take off depends entirely on the type of equipment used, but if everything is magical, and the plane has an infinite thrust threshold, then of course.. it would overpower the friction variable in the wheels, bearings and weight of the plane. It isn't that difficult to imagine.

You are f****ing retarded if you don't think the plane could take off, whether or not Mythbusters proved it.

I am not trying to insult but it made me laugh when I read your comment and then read the domain name meignorant.com

ITs so applicable :-) Sorry could not resist its just funny.

Anyway I was also wondering about the tearing tarp. Now if they fakes that take off it really does not matter to me. IF they did (and I do not think they did) it was for reasons other than to fake results. (probably money IE too expensive to use a better tarp material)

The physics here are sound folks. I can end all debate with this simple knowledge. Do you really think an airplane NEEDS wheels in order to take off ? Explain SKI planes? Float Planes? HOVER Planes (yes someone made a plane where the landing gear consisted of a HOVER craft airbag)

The wheels serve ONE purpose and ONE purpose only. To allow you to easily roll along the ground till you have the airspeed to take off. Thats it. BY DEFINITION a treadmill would never effect the take off of an airplane.

IF IT COULD no plane could ever take off going East. While going east YOU ARE ON a 1,000 MILE PER HOUR treadmill. Oh you did not know this? what you think this planet is sitting still? its REVOLVING folks. Spinning. JUST like a giagantic planet sized treadmill. The average SURFACE velocity of the earth is 1,000mph.

THAT MEANS when you walk EAST your actual veloity (ignoring the velocity of our orbit the velocity of our solar system and the velocity of our galaxy) is your walking speed PLUS 1,000mph SO if you walk 5mph east your going 1,005mph if you walk 5mph west your going 995mph

Velocity is RELATIVE. velocity has NO MEANING without something to COMPARE it to. Something to MEASURE against. Right now your going THOUSANDS of miles per hour. Relative to the center of the earth your spinning 1000mph. I have no idea what the orbital velocity of the earth is but your going that fast relative to the center of the SUN (plus and minus your 1,000mph rotational velocity by being on earth) and then the SOLAR system is ORBITING the center of our GALAXY and on top of that our GALAXY is moving withing its local luster AND our local cluster is moving relative to the universe as a whole.

SO right now we are moving THOUSANDS of miles per hour.

Motion is RELATIVE to something else. WE ignore the rotational velocity of the earth because we are ON the earth moving with it. JUST like INSIDE your car your "not moving" relative to the car ie 0mph velocity. BUT your going 60mph relative to that SIGN you just drove by.

Is that starting to make sense? Relative Motion that is INTENDED is when you THRUST or PROPEL yourself. newtons second law for every action there is an equal and opposite reactions.

Let me give you an example. Stand up. Pick something up from your table or desk and THROW IT across the room. What happens?

Well the Object goes flying the way you threw it and YOU go flying the opposite direction.

Screeeeeech all stop you say. I did not move. ? Well actually yes you did its just that the energy needed to make you move IE to overcome your inertia in 1g and the overcome your muscles is MUCH greater than the force needed to throw that pen.

What you need to do is start watching some Nasa videos from orbit. When an astronaut PUSHES another astranaut they BOTH go flying equally in opposite direction (if they are of roughly equal mass)

This even means that when an astronaut pushes on the the SHUTTLE and goes flying across the space the SHUTTLE ALSO goes moving in the opposite direction. We do not see this easily because the shuttle is so much more massive than the astronaut.

WE humans make the mistake of equating equal FORCE to Equal MOTION and this is just not how it works.

To move an object to X velocity takes a certain amount of FORCE. the heavier the mass the MORE FORCE you need to acquire the same velocity (except gravity it applies forces evenly independent of mass differentiation)

In OUR world we ALSO must account for DRAG. SO even if two objects have the same MASS they may still require different amounts of FORCE to move them if they have differing amounts of DRAG so a Pickup Truck will take more FORCE to get to 60mph than a RACE CAR of the same exact mass. The race car produces less DRAG so will not encounter as much resistance from the air when you push it.

People seem to IGNORE forces they do not readily encounter so the next time your trolling around town at 25 mph put your hand out the window.

NOW the next time your going 80mph down the freeway DO the same thing. Amazing ehh?

NOW How does this apply to the treadmill. WELL there are different ways of APPLYING force.

HOW is the treadmill "moved" ? I can think of TWO ways to spin a treadmill. I can grab the treadmill with my hands and MOVE IT or I can put paddles on the treadmill and BLOW high powered air across the paddles MOVING it.

The point? there are different ways of applying force.

NOW I want you to do an experiment. Goto your local DOLLAR store and buy one of those little battery powered FANS.

NOW take a pieces of Styrofoam and put a rigid SAIL in the front of it (heck you an just tape another piece of FOAM to it)

NOW hold that fan in your hand and AIM it at the sail. What happens? off course the sailboat moves.

NOW attach another piece of foam to the sailboat so you can MOUNT the fan to the sailboat but I want to to KEEP the fan as it is IE aimed at the sail.

What happens? Well nothing happens the boat just sits there (it MIGHT spin but thats a completely different force and were not going to get into it but it has to do with precession and the spinning propeller IE if you GRAB the propeller on the fan and TURN IT ON while holding the propeller and NOT holding the body you will notice the FAN now spins but the propeller does not because your holding it. Make a mental note if you try that notice the FAN does not spin nearly as fast as the propeller does) I will get into that more later if you desire for now lets ignore it.

WHY does the boat not move like it did when you pointed the fan at it? THIS is action reaction at work.

This happens in BOTH experiments but the results are different and here is why.

WHEN the fan pushes the air one way its also pushing ITSELF in the other direction (action reaction)

When I am holding the fan these forces are SEPARATED from each other. The moving air is pushing the boat but the REACTION to this is "disconnected" from the boat. That force goes into my HAND ie it pushes my HAND in the opposite direction. Because my hand is NOT "force connected" to the boat it does not stop the boat from moving. Your thinking why did I not say PHYSICALLY connected to the boat. Thats because its NOT the physical connection thats important its the FORCE connection.

NOW when you attach the FAN directly to the boat and try to BLOW into the sails nothing happens. One again. the fan blows air which imparts a FORCE to the sail BUT it also applies an EQUAL and OPPOSITE force to the FAN trying to move the fan in the OTHER direction. NOW because the fan is physically connected to the boat the FORCE component is ALSO connected to the boat. because its in the opposite direction the boat does not MOVE. For every Action there is an Equal and Opposite reaction.!!

NOW you say WAIT if I aim the fan in the other direction the boat moves. AHH but now its not a SAIL boat its now a POWER boat.

In our first experiment the "force" that ultimately moves the boat is NOT the fan but the AIR hitting the sail.

In the case of turning the fan around the force now moving the boat is the EXPELLING of air from the fan DIRECTLY.

Action Reaction. I shove a bunch of air behind me with force the equal and opposite reaction is for ME to go the other way ie forward.

NOW I am very heavy. AIR is very light. THIS is why we have to move SO MUCH air with a big propeller and big motor. This mens you needs a LOT MORE AIR in order to move the much larger mass of you the boat etc..

THATS why we use propellers in the WATER to move the boat and NOT propellers in the air. WATER is a LOT heavier than air so I need to move a lot LESS of it (same force mind you just less MASS)

In an airplane the only medium we have to move is AIR.

SO why am I telling you all this? well you need to understand FORCE components and there application in order to understand this treadmill experiment.

The only way to MOVE an object is to apply a DISCONNECTED force component to the object. IE I have to physically SEPERATE the ACTION and REACTION components. If they remain inside the same relative system nothing really moves.

SO if I am INSIDE a cube in space and I PUSH on one wall what happens? well the CUBE moves one way BUT I move the OTHER way with EQUAL force.

When I hit the other end of the cube those forces are one again encountered in opposing direction and cancel each other out. IE no net movement.

If I am OUTSIDE the cube and do the same thing WELL the cube DOES move but again SO DO I the NET force is ZERO.

In order to move that cube without also moving me I need to PUSH against something. Say a planet. NOW its important to understand something. I did not want to broach this but I have just created a conundrum that if you are actually understanding what I am saying your raising your hand right now and saying but but but.

Your right. ALL forces movements are NET ZERO in FORCE (action reaction again) but remember we are talking RELATIVE motion not absolute Force. SO we limit our relative field of reference. The MOTIONS are not the same as the FORCES. while ALL forces are net zero the motions are NOT net zero because heavier things require MORE force to move at equal velocity.

When you JUMP up in the air believe it or not the EARTH is being moved in the OTHER direction with equal force. but the earth is SOOO much more massive than you are that the EFFECTS of that small force you applied to the earth are all but invisible to us. This is the distinction between FORCE and MOTION. Force is always equal but RESULTANT MOTION depends on mass and drag.

For an example of this we need TWO boats. Build yourself two EQUAL foam boats. Add a LOT of mass to one of the boats make it 10-20 times heavier than the other boat. Build a rig to PUSH the boats apart attached to one of the boats. I am thinking a dowel rod through STRAW with a rubber band and and some wraps of TAPE around the end of the straw so it can not LEAVE the straw. Push the dowel in (lock and load) and use a small peice of tape to hold it there. Small enough so eventually the tape GIVES and releases the dowel. Put the boat together so the dowel will PUSH on the heavier boat. Make it all steady so the water is still MARK the tub where they meet. NOW gently let them go. if you did it right nothing should move much. Once the tape lets go and the DOWEL is pushed with the rubber band your going to notice that the lighter boat MOVES. NOW carefully look at the heavier boat and the MARK you made on the tub.

Interesting huh? IT also moved away but not nearly as much as the lighter boat?? the force was applied in BOTH direction action reaction but the resultant MOTIONS differed because the mass and even drag of each boat was different so the AMOUNT of forces needed to move them is different. Since the force is EQUAL one moves MORE than the other.

SO what we need to do is apply an EXTERNAL force IE something "outside" this limited relative system. WELL lets use YOU. HOLD the small boat in place with your hand and NOW see what happens when the dowel pushes. the heavier boat moves MORE than it did before. This is because I made the system UNEQUAL (its actually still equal I just increase the SCOPE of the system by including YOUR boat and mass etc..) so MORE motions now results on the side of the larger boat because the LIGHTER boat is now heavier with the addition of YOUR mass to the system.

SO to make something MOVE we have to apply a force and we need that force to be EXTERNAL to the local system we want to move relative too.

OK that should be enough information to START to attack the treadmill problem. You see to understand the treadmill problem you need to understand FORCE components and whether they are connected or disconnected to the limited loal system we are comparing to.

OK "HOW" does a car derive MOTION. Lets start with the engine. Inside they engine a combustion event occurs in the cylinder. the engine is heavy and attached to the car which is even heavier. SO although those force is applied in ALL direction equally IE outward from the spark plug ignition point we are doing the same thing as YOU holding the smaller boat. the PISTON is light compared to the entire mass of the engine and car. so MORE relative motion goes into moving that piston. up and down they go. we CONVERT this up and down motion into a ROTATION using the am shaft. Through the transmission drive shaft differentials axles and wheels we TRANSFER this rotation movement to the wheels.

The WHEELS are directly in contact with the GROUND. A CAR does not move by THRUST it moves by DRAG or FRICTION.

It starts as thrust (combustion in the cylinder) we harness that THRUST to move piston and covert that thrust into ROTATION of something eventually the wheels.

To simplify this into THRUST component imagine your inside the wheel. the tangent is where the wheel TOUCHES the ground its flattened out a bit but either way there is a point at which the wheel touch the ground. if I PUSH back on the wheel segment the CAR will want to move in the other direction. but this "thrust" it dependent on FRICTION between the wheel and whatever its resting on. For a clear example of this try driving on ICE. A lot less FRICTION so its a lot harder to move. Its no harder to move the wheels its just harder to TRANSFER that motion to what your resting on to in the end move the car. THE ENGINE does not move the car. The engine moves the piston which moves the wheels the FRICTION between the wheels and the ground is what moves the car.

SO how do we measure the SPEED of the car? Not technically but IN REAL LIFE how do we measure it? why by how much ground we cover. IE going from point A to point B. We accept that the GROUND is not moving and the car is moving OVER the ground. But wait did we not forget? this planet is MOVING its spinning on its axis and revolving around the sun and the whole solar system etc.. etc.. etc..

Remember RELATIVE motion in a limited system. we want to MOVE on the planet so for the purpose of this discussion we can say the planet is "not moving" (even though it really is)

We measure speed by comparing out motion to "stationary" objects on earth. Passing that sign or city. Miles covered over ground in X time. 60mph means in 1 hour of time we travel 60miles on land over the earth.

SO what happens on a treadmill On a treadmill you have FURTHER reduced your "local relative system" to no longer include the earth. BUT you DO include the earth in your OBSERVATION.

Get the car going 60mph and relative to the surface of the treadmill the car is going 60mph. Don't believe me? stick your hand out and touch the treadmill. It won't feel good.

BUT relative to a position OUTSIDE of this local system IE you NOT on the treadmill and it seems like the car is just sitting there spinning its wheels.

SO where is the force going? action reactions remember you go one way what your apply force to goes the OTHER way. Well the car is apply force to go forward the REACTION is that the surface of the treadmill goes the OTHER WAY.

Action Reaction. The car moves by converting FORCE into a thrust component that is DIRECTLY connected to whatever surface its resting on in this case that means the treadmill.

THIS car on TREADMILL experiment is IDENTICAL in force components to the SAIL boat with the fan ON the boat blowing on the sail. The forces are limited to the local system and DIRECTION connected to each other. NET motion is zero

Its very important that you understand this. If you put a car on a CAR treadmill it will not move relative to a frame of reference NOT connected to the treadmill.

If you put an AIRPLANE on an AIRPLANE treadmill the SAME THING will happen. Within that limited local relative system the plane WILL NOT MOVE when seen from outside that system.

BUT your still wrong :-) you see your not putting an airplane on an airplane treadmill YOUR putting an airplane on a CAR treadmill.

This concept of a treadmill nullifies a force applied on its medium which is ground IE the surface of the treadmill. SO anything that applies its motive force laterally on this treadmill will appear to have that force nullified IE the car sits there going no where.

An airplane however DOES NOT apply its force component to the surface it sits on. It applies its force components to the medium it TRAVELS through IE the air itself.

It gets even MORE complicated than this. The treadmill would NOT stop the car from moving It would only stop the car from moving in the direction opposite that which the treadmill is going IE the car can still go LEFT RIGHT just not FORWARD or backwards.

A car moves on TWO dimensions. An airplane moves on THREE dimensions. Forward Backward - Left Right - Up Down.

SO even if you put an airplane IN (3d there is no ON its IN) an airplane treadmill otherwise know as an AIR TUNNEL the airplane would STILL be able to take off. It just would not be able to go FORWARD or Backwards.

The airplane moving side to side or up and down is like a car moving side to side. THE ONLY force component these treadmills would effect are the FORWARD BACKWARD components.

As soon as the wind tunnel ramped up to "take off" speed the airplane WOULD lift off. It just would not be able to gain forward progress.

The SPEED of an airplane is irrelevant in its ability to fly Only one thing matters AIR traveling over the wings with sufficient velocity to generate the needed lift.

As for the air plane moving forward the ONLY way you can STOP a plane from moving forward (OR anything that THRUSTS with AIR) is to MOVE THE AIR. Moving the ground does nothing but making the wheels spin faster.

If I power the airplane to a level that would normally make it go 100mph and then I put it into a HEADWIND of 100mph what happens ?

WELL an airplane measures speed in TWO ways (3 actually but the third is a component of the second ie lateral velocity but thats irrelevant to this discussion)

AIR Speed and Ground Speed.

AIR speed is how fast the AIR is moving over the wings of the aircraft. Ground speed is the speed you and I would measure if standing motionless on the surface of the earth. IE the speed from point A to point B

This is why airplanes sometimes take longer to get from this city to that city OR they get there faster than would normally be possible.

Lets say your flying at 600mph and traveling 1200 miles. If the wind speed is 0mph making your airspeed equal to your ground speed then you would get there in 2 hours.

IF however you have a 100mph TAILWIND ie wind pushing you from behind and you apply the SAME amount of "thrust" your airspeed is now 500mph BUT your ground speed is now 700mph. Your going forward at 600mph with 100mph wind pushing you from behind so you subtract the 100 from your 600 and you get an AIRSPEED of 500mph IE if the wing of the airplane was your UNIVERSE and you were standing on it with a wind meter it would read 500mph.

NOW since your thrust forward with 600mph and have a 100mph tailwind pushing you this INCREASES your effective GROUND speed. SO if you were a car on the ground you would have to go 700mph to keep up with the airplane.

IF on the other hand you had a HEAD WIND the reverse would happen your ground speed would go DOWN and your WIND SPEED would go up. To make matters WORSE your aircraft has a maximum safe speed at which it can fly. Most airliners can NOT go supersonic and survive. so in a theoretical 100mph headwind you would have to LOWER your power output so your TOTAL airspeed was below your maximum safe flight speed but thats a technicallity. I used 100mph so the math would be clearer.

It also does not matter how you design this treadmill. I have seen it described TWO ways. one is the treadmill always goes in reverse at the same speed the airplane moves forward. The other is the treadmill always goes in reverse the same speed that the WHEELS of the plane are going.

They are both wrong and they both have MAJOR logical problems.

If we look at case #1 treadmill goes in reverse at the same speed as the airplane is going forward. First logical this means its impossible for this treadmill to EVER prevent the airplane from moving. If it prevented the airplane from moving the airplane would be moving at 0mph and therefore the treadmill must also be going 0mph but the airplane THRUST with air so it MUST move. Its a logical falicy. WELL lets ignore this logical error for now.

The airplane WILL move (or the treadmill fails logically) so now the question is can the treadmill keep this now moving airplane from taking off ?

First some logical conclusions. IF the airplane LEAVES the treadmill the speed of the treadmill becomes irrelevant. Agreed? I mean if its not touching the airplane it an not effect it any longer.

With this information at hand its easy to calculate the MAXIMUM possible treadmill speed. It happens to be whatever speed the airplane needs in order to take off. Lets say the plane can take off at 100mph.

SO the maximum speed the treadmill will achieve while still effecting the aircraft is 100mph.

The airplane WILL move since its thrust with AIR and not with a Ground Friction interface like the car. If the airplane moves it WILL accelerate. The ONLY way in which the treadmill can impede the progress of the airplane is with DRAG namely the drag of the wheel to the treadmill surface and secondly the drag of the wheels very ability to roll IE the bearings.

SO the question here is CAN the total drag of the airplanes wheels and bearings at twice its takeoff speed be greater than the ability of the aircrafts propeller and engine to push the airplane forward?

Simple answer not a chance in hell. The rate that atmospheric drag pulls on the airplane as it goes faster climbs MUCH MUCH faster than the rate at which the drag in the wheels and bearings increases since the airplane an EASILY fly at well over twice its take off speed there is no question no where near enough drag could EVER be generated by the ground wheel interface and bearings. In fact this drag is downright negligble. You would have a tough time measuring the different between the airplane taking off a runway and taking off on the treadmill. It would be that tiny a difference. In fact this treadmill would HELP the airplane take off (more on that later)

This is the treadmill they used on mythbusters. Since they knew the aircraft could take off at 25mph they knew they did not need to move the treadmill any faster than 25mph to perfectly replicate this challenge.

NOW the second treadmill does not exist. People on the internet who refused to accept that force does not work the way they think FABRICATED this second version to LATCH ONTO the ONLY fragment of truth they could find IE that the treadmill would increase the drag of the ground wheel interface and bearings.

IE that the treadmill would always equal the speed of the WHEELS themselves.

BUT this treadmill has a massive logical falicy. From the first demonstration we KNOW the airplane WILL in fact be able to move forward. This is not arguable. If you desire to argue this please keep reading the first half of this post and perform the described experiments until you understand the concepts of Force, Motion, and Relative frames of reference. I am not trying to belittle anyone but to discuss this matter you MUST understand the factors that are in play here.

SO the airplane WILL move. well here is where this second treadmill instantly fails. at this point both the wheels and the treadmill must INSTANTLY accelerate to an INFINITE velocity.

The MOMENT the airplane moves the treadmill must equal the speed of the wheels. BUT this creates a problem because SINCE the airplane is accelerating forward and the treadmill is instantly and equally accelerating backwards mathematically the wheels of the airplane must ALWAYS be going precisely TWICE as fast as either the airplane is moving forward or the treadmill is moving backwards which means the treadmill would instantly DOUBLE its velocity to equal the wheel speed but in so doing has INCREASED the wheels speed yet again. This effect would occur instantly and would go to INFINITY.

Clearly such a situation is impossible even with VERY lenient mental discussion. Its just silly BUT lets go with this. Lets assume such a treadmill IS possible. You say the drag on the wheels is sufficient to now stop the airplane. Well no its not quite that simple. YOU just granted yourself a reality exemption with your impossible treadmill so I get a reality exemption too. IE wheels and bearings capable of holding up to the same speed that your treadmill can hold up to.

If you can say my wheels will fail then I can say SO will your treadmill and one it grinds to a halt I take off since your treadmill is larger and heavier it will fail first.

SO with the reality exemptions in place would the airplane take off IE could the infinite velocity of the wheels and treadmill produce enough friction to stop the airplane from taking off.

Well no. Here are two reasons why. First we have agreed that the treadmill has friction. If it did not I could just apply my BRAKES which would stop my wheels from spinning at all and they could now effortlessly slide over your frictionless treadmill and I would take off. Since you don't want that we must accept that your treadmill also has friction its what your using to stop my plane after all.

Well now you have another problem. When this treadmill starts up my airplane would take off almost instantly. You see the treadmill also has friction with the AIR above it. To see this flip your bike over and get the tires going at a nice clip and put your hand close to the tire without touching it. Feel that air? thats what would happen over your treadmill. This air would VERY quickly get up to my minimum take off speed and I would simply LIFT off the surface of the treadmill. Once I am no longer in contact with the treadmill I could accelerate through the air normally.

If you an remove the friction with the air then I can remove the friction in the bearings. So now I have infinitely fast spinning wheels but since they are frictionless the airplane STILL moves forward and takes off normally.

There is simply NO logical way to design ANY treadmill that can keep an airplane from taking off. Its just not possible. If you use a ground force treadmill IE car treadmill it will have absolutely NO effect on the aircraft at all. If you use an AIR effect Treadmill ie a wind tunnel ALL you can do is keep the airplane from gaining any ground speed it would STILL take off. An airplane does not need to move forward to take off it just needs air to move over the wings with enough velocity.

EVEN if wheels could produce enough friction all I have to do is eliminate the wheels. Put skis on it. Put floats on it. An Airplane does not REQUIRE wheels. They even made an airplane once with HOVERCRAFT landing gear.

I will NOT be responding to any posts that ignore or can be answered simply by reading my post here or by performing one of the experiments. IF you have a question that I truly did not address (not likely I think I was pretty thorough I spent over 2 hours typing this) but if you do come up with one I will try to answer it.

While watching the film I couldn't help but notice the stark shadows the cones were making on the tarpaulin. As you can clearly see in replay the shadows are evenly spread out in conjunction with the cones casted over the tarp! This creates the illusion the "flat" tarp is not in motion when in fact the entire time it was being pulled by the truck. Your eyes decieve you thinking the shadows are some kind of wrinkle or kink as shown in your handy little gif animation above giving you the effect of the tarp staying completely stationary. The tarp is indeed moving and their experiment was a success! Your Myth Buster conspiracy theory is... BUSTED! Dude I should win a prize! I came here by way of digg.com fyi.

The Mythbusters failed to replicate the myth on this one. The plane is supposed to remain stationary relative to the ground. Booth planes presented on the experiment -- the RC and the light plane -- can bee clearly seen moving forward, picking up speed and thus building lift on the wings resulting in a take off.