The Plane Will Not Fly
 

Very interesting ideas bouncing around, but the plane would not get off of the ground, based solely on the scenario.

Thrust, although it creates a suction at the intake and moves air through the engine, that air in no way creates lift.

To cause a winged aircraft to rise there must be lift. Lift is created by the air moving over and under the wing. This is done (absent of other influences) by forward movement.

In the scenario, AS STATED, no adds or creative influences, there is nothing present to create lift. Not the engine thrust, suction or pressure, the engine isn't a player (an aircraft could be pulled forward with a tieline and it would have lift), Not the conveyor belt, it reacts or actually COUNTERACTS any forward movement created by the engine.

There is no mention of wind tunnels, updrafts, downdrafts or any other thing that is moving wind in order to create lift.

If it was possible, for the airplane in this scenario to take off, aircraft would not need any runways at all. They would crank there engines, throttle up and away they would go.

I have had my hands on a operating F-16 (on the ground) at full throttle while performing maintenance, and I never saw one starting to float upward beacause of the "thrust". They go airborne when they move forward.

In the given scenario, with the boundaries applied, and the conveyor counteracting any attempt at forward movement, it is scientifically, and physically inpossible for the airplane to fly.

The wheels counteract the reverse motion of the conveyor belt by rotating at twice the speed.

The airplane will fly.

Why would they rotate at twice the speed? The opening post states that the belt matches the speed of the plane. In other words, the plane is stationary and no lift is created.

The belt matches the speed of the plane, in reverse, (that is key)! If the plane moves the belt moves and simply spins the wheels faster! The engines propel the plane forward and the wheels get spun faster by the belt. The belt makes no change to the actual forward speed of the plane. In fact if the plane does not move, the belt does not move!

Remember that the belt just turns the wheels, it does not actually move the plane at all.

It will fly!

Mike

hmmm
 

i think the plane would stay on the ground being that it would only reach half it's take-off speed before it runs out of runway.


Is there an actual answer?
Oh Yeah! Is there really a MENSA member in here?

It would reach it's full take speed, not half speed. Only the wheels get turned by the belt, the planes speed is not affected. Wheels Roll!

Mike

Hi Joel and welcome to DVinfo! Always nice to meet a fellow servicemember, past or present. I recently retired from the USAF and have been HOTAS in many jet aircraft, including the Block 52 F-16, both on the ground and in the air.

Well, I thought this riddle had run its course a while ago even though not everyone was convinced of the correct answer: the jet will fly. Richard and others have given the answer, but here it is again just stated in different words. When the burner lights, it doesn't matter if the ground does start rolling backwards (a la our imaginary treadmill), the wheels will just spin faster and you'll be going somewhere fast as all that thrust propels the jet. There'll be weight on wheels until flying airspeed is attained and enough lift is generated by the wings to climb, but the wheels spinning ever faster against the receding ground would not (in the theoretical world) impart drag to the jet to counteract the thrust driving it forward.

OK .... the plane takes off, it reaches full speed in the same distance and takes off. It will do this even if the belt/runway moves at double the speed of the plane, because the belt exerts no force on the plane to hold it back. The faster the belt moves, the faster the wheels spin, but the engines keep pulling the plane through the air. As they do, they bring the airframe (and wings) to take-off speed, the wings create lift, the plane lifts off.

The wheels are spinning like crazy, because the plane is moving forward and the "ground" is moving backward, but the wheels are not holding the plane back, the plane is not prevented from moving forward like it would be restrained for a maintenance situation.

To demo this for yourself...
Tie some string to the front of a toy car (or toy plane with wheels). Bring this to the nearest treadmill.
Put the toy on the belt, hold the string and crank up the treadmill speed.
Note that regardless of how fast the belt is moving, you can still pull the toy forward as fast as you like by tugging on the string. You pulling on the string is the same force as the engines pulling/pushing air.

Yes, there's a little extra friction to overcome, but it's really almost nothing in relation to the thousands of pounds of force that these engines are capable of producing.


PS: Just wanted to add a very heartfelt thank you to Pete, Joel and every other past and present service member here!

I don't know how to make it any clearer.

The engines generate forward thrust ON THE AIRFRAME.

In order to counteract the forward thrust, and 'keep the plane stationary'... the 'conveyor belt' runway must exert EXACTLY THE SAME THRUST in the oposite direction ON THE AIRFRAME..

The belt only touches the airplanes wheels.

The wheels ROTATE in order to eliminate the drag of the runway. They do this at whatever speed the plane is moving forward and the ground is moving 'backwards' in relation to it.

IF the belt were moving backwards at three times the forward velocity of the airplane, it would still not exert enough 'drag' to stop the aircraft, the wheels would simply rotate faster. Sure, a little more heat and friction in the wheel bearings, but not enough to stop the aircraft.

The plane will fly.

And this is absolutely my LAST posting since I first posted the answer.

is it that serious? lol. I thought the Conveyer belt was turning in the same direction as the the plane was to be moving.

I think this needs to be sent to "mythbusters."

Guys Guys Guys!

Come on! It is not that hard. The plane has wheels to roll freely on. If the belt goes one way the wheels roll twice as fast, if it goes the other the wheels don't roll at all. The plane still moves and takes off.

Now I'm like Richard, I'm done posting! :) :) :) And, don't say thank God! :)

Mike

Exactly! Had to think this through for a few minutes.

The wheels are, in effect, bearings that decouple the airframe from the conveyor belt.

Now, if the 747 had skids instead of wheels, that would be different....

Them guys will actually try that thing out too!

The Plane will not Fly, or The Plane will Fly.
 

In the scenario as stated, the conveyor belt reacts to changes in speed of the aircraft, not the speed of the wheels turning.

The folks that have this fictitious airplane flying, (in this fictitous situation), create forward motion by adding outside influences.

If the conveyor belt adjusts it's reverse speed based on the speed of the wheels, or ground speed, thrust would absolutely overtake the actions of the conveyor, forward motion of the aircraft would occur, lift would be created, and the aircraft would fly.

If the conveyor belt adjusts it's reverse speed based on the speed of the aircraft, or airspeed, thrust would not overtake the reverse action of the conveyor, the plane would remain stationary, no lift would be created, and the plane would not fly.

So, depending on how you want this conveyor belt to measure speed determines whether or not it will fly.

The data provided in the scenario is incomplete. It is a hilarious read though, and a great way to kill some time. Although... I've got 2 one hour videos to produce, and a 2 minute commercial to finish before Friday...

Maybe I am not smart enough to understand the complexities of this very simple scenario as I am not a MENSA member, but I did ride the short bus to school on occasion.

But I did stay at a Holiday Inn Express...
 

Joel:

That has been my argument from day one on this thing.... but then I am not mensa either.... but I did stay at a Holiday Inn Express last night.....

Planes that Fly
 

I just think the discussion is fascinating. I love hearing different arguments and theories for or against the plane being able to fly.

It is amazing to me which question, riddle or whatever will become a widespread discussion on a forum or other internet sites.

It is apparent to me however, that this forum is attended by some extremely bright and intelligent people. This is an off topic discussion, the really amazing ones are the discussions about true applications in video and it's associated technologies that are accomplished on this forum.

The results in that arena are demonstrated hourly by the members of this forum.

I procured, tested, setup and began a video ministry at my church totally from the information gleaned from the amazing folks here at DVi. From cameras, to tripods to spider braces, steadicams, NLE's plug-ins or whatever, the best in the industry are represented right here. The invaluable contributions by you folks in other threads here saved me countless hours and lot's of dollars. (you can see the results after only 3 weeks at kbbc.org)

So all that don't see eye to eye on planes and conveyors, thanks for your other contributions on this forum.

Joel, it's not really about being super smart but just being familiar with physics. And physics is tricky because sometimes your intuition does not always match the physics. For example, if you asked someone what would fall faster in a vacuum, a hammer or a feather, most people would say the hammer because their intuition says it's heavier. But the physics say they will fall at the same rate and this was even proven by one of the Apollo astronauts on the moon.

In this case, it doesn't matter whether the conveyor is measuring the speed of the wheel or the plane. If you're interested, here's a scientific explanation:

To scientifically prove this, a physicist or an engineer would draw a "free body diagram". This is a diagram showing all the forces acting on the plane and in which direction. In this case, the forces in the horizontal direction are what we are interested in and there are only three forces acting in this direction: friction between the conveyor and the wheels, drag from the air and thrust from the jet engines. Friction and drag forces "point" backwards and thrust "points" forward.

So for the plane to remain stationary, the sum of the friction and drag forces would have to equal the thrust force. We already know thrust can overcome drag--a plane does this all the time otherwise it can't move forward. So the question is, can thrust overcome friction? Yes, it can. The plane already does this every time it moves on the ground. The friction is no more than if there was no conveyor there at all or if the conveyor was moving like crazy in the opposite direction. The wheels are just spinning faster. In fact, the friction gets less as the wheels start rolling (just like how it's easier to push a car after you get it going). The equation for friction is f = µN , where f is the friction force, µ is the coefficient of static or kinetic (rolling) friction and N is the normal force to the direction of the friction force (in this case basically the weight of the plane).

wish I'd never read this thread
 

Hi All,

this thread is a good way to waste some time. Here's my two cent's anyhow.


In short, it depends.


If there really is no rolling resistance with these wheels then the conveyor has no effect as many have stated. The plane flies (assuming it could fly in the first place).

If there is rolling resistance and this is constant with the wheel speed, again the conveyor has no effect and the plane flies.

If for what ever reason the rolling resistance resistance is not independent of wheel speed (i.e. the wheels have tyres or any such real-world features) then it depends again.

Scenario 1), the increase in rolling resistance due to the wheels rotating at double speed is sufficient that the maximum engine thrust balances the overall resistance (rolling + air) before the plane can reach a ground speed (relative to still ground NOT conveyor and assuming no wind) prior to take off. Plane does not fly but carries on travelling a constant speed.

Scenario 2), increase in rolling resistance is such that the plane has sufficient thrust to reach lift off speed. Plane flies.

Both off these scenarios are depicted on the attached link.
http://www.physics.ox.ac.uk/users/smithdmd/planes.bmp


regards

David Smith

Not sure if I understood what you are saying (you must be MENSA), but I have contended that the Gravity force down, creates an a drag on wheels that has to be overcome. I think those that are saying the plane will fly are ignoring the tremendous force of 200 tons of weight on tires and bearings, etc., and the what is need to overcome that. When a plane is sitting on a tarmac, it takes a tremendous thrust just to get the plane rolling. It certainly doesn't. With the plane on a "moving" tarmac, you still have to overcome the same forces. The scenario states that when plane speeds up, conveyor goes faster to counter act. So the way I saw it, at rest, all force on plane is straight down, by virtue of gravitational pull. Then, as engine starts, the forces exerted change the general vector of forces on the plane forward, but then the belt speeds up to counter act the forward thrust, and the forward vector thrusts are counter acted, due to the reverse vector force applied by the sped up conveyor belt... According to the scenario then, at the point the engines reach maximum thrust, the conveyor belt will be counteracting that forward thrust using the downward force of gravity, and the reverse thrust of the conveyor. Airs speed required for take off should never be reached.....

Actually, even at idle thrust, you're well advised to keep your feet on the brakes at the Hold Short line in most jets I've flown. Even if you consider the dynamic drag of the rolling tires, the horizontal force vector is at least an order of magnitude less than the thrust of the engines, probably a couple orders of magnitude at full thrust. Think of the "land speed record" type of jet cars...300+knots ON THE GROUND...ground speed as high as in our experiment except that there's also 300+knots worth of aero drag as well, instead of just 150 knots! If the jet car grew wings, it'd fly.

In any case, as I mentioned several pages ago, this is a thought experiment and the convention is that you don't get to add your own set of variables to thought experiments. Calculating the rolling resistance just wasn't set in the conditions of the riddle.

Easy. It's basic math.

Throw ten rocks on the ground. Then pick up the ten rocks. How many rocks are left on the ground?

Answer: 0

The airplane example is just to get you to think about jet engines, rolling resistance and lift on the wings and blah...blah..blah.. to confuse you. It does not matter if the object going down the belt at 10 mph is a jet with large tires, a car, a skateboard with small tires, a beachball, explosive diarrhea, space shuttle, or Carl Lewis sprinting down it.

10 mph is 10 mph. I could put a "Slip & Slide" on a belt. If I slide down it at 10 mph, and someone turns it on to 10 mph, I'm going to become stationary.

This like the 10 pounds of feathers vs. 10 pounds of steel question.

Am I a member of MENSA now??

Actually, it matters a great deal, as the dynamics of these examples are not all the same. This has been amply explained by some of the previous posters, who must be groaning in frustration when they see how their efforts have failed to penetrate the reasoning barrier. What role in evolution do you suppose this barrier has played for Humans? Perhaps it provides a necessary brake on runaway technological development, without which, we would have exterminated ourselves long ago.

I can imagine a comparable dilemna 50,000 years ago, when the inventor of the spear-launcher tried unsuccessfully to convince the other members of the hunting party why it was better to have a doubled throwing range.

This dog won't fly.

You can leave the wheels out of the discussion. Assume the plane has frictionless wheels with no mass. The engines provide thrust as Richard has correctly described. The wings require air flowing over them to provide lift. The engines do not provide this airflow, it is provided by the movement of the aircraft relative to the air. If the aircraft has a rotation speed of 100 knots and there is a tailwind of 10 knots the airplane will rotate at a speed relative to the ground of 110 knots and the pilot will see 100 knots on his airspeed indicator (ASI). If there is a headwind of 10 knots the aircraft will rotate at 90 knots ground speed and the pilot will see 100 knots on his ASI. If there is no wind and a seaplane is on a river flowing at 10 knots and the pilot takes off in the direction opposite the flow of the river he will depart the Earth when his speed relative to the ground is 100 knots and his speed relative to the river is 110 knots. His ASI will register 100 knots.

If the airplane's forward movement is offset by movement in the opposite direction as in the conveyer belt thought experiment then there is no airflow over the wings and therefore no lift. The ASI will register 0 knots and the airplane will not fly.

For the last time.

The airplanes forward movement is NOT offset by the converyor belt.

There is NOTHING offsetting, or counteracting the thrust of the engines.




AB SO LUTELY NOTHING is offsetting the thrust.

The converyor belt interacts with the wheels, and the wheels ROTATE twice as fast, to offset the conveyor belts backward movement. It's as simple as that.

Simple Math.

As I stated in POST #11 and other posts thereafter. In order for the thrust of the engines to be 'negated' an equal and opposite thrust must be provided. AGAINST THE AIRFRAME. For this is where the thrust is being applied. There is no force being applied against the ground by the wheels in order to get the plane moving, such as there is in a car to get a car moving.

The movement of the conveyor belt applies friction againts the wheels, and the wheels ROTATE in response to this friction.

That is the function of the wheels. It takes comparitively little force to get the aircraft moving, in fact. Anyone recall the truck commercial (Dodge I think) that had a truck towing a 747? They made a big deal about it untill volkswagon towed one. The wheels and bearings are designed to minimize the friction.

If your plane was attached to a rope anchored a the front end of the runway, and the converor belt was started up, with the engines OFF - the wheels would ROTATE under the plane, without the plane moving. THE wheel rotation is INDEPENDENT of the planes 'ground speed' because of the static force of the rope, which acts on the airplanes body independant of the rotation of the wheels and speed of the converyor belt.

Same for a person in rollerskates standing on a treadmill and holding onto the side bars. The wheels rotate at whatever speed the treadmill passes under them. The motion of the person standing is independent of the treadmill, because of the static force between his hands and the rails. He can even PULL himself forward on the treadmill, and the wheels on the rollerskates will rotate FASTER than the treadmill, because of the added forward momentum. Because his arms on the sidebars are INDEPENDANT FORCES acting on his body, not interconnected or related to the treadmill. Just. Like. The. Engines.


The Planes thrust is generated independent of the motion of the wheels. The planes forward motion is NOT generated or determined by the velocity of the wheels rotation. The planes wheels are simply acting as 'bearing's to 'lubricate' the friction between the ground and the plane. The wheels are not turning when the plane lands, and that doesn't stop the plane. They simply accelerate up to speed as the plane lands. That is their function. As the plane applies thrust it will move forward. The converyor belt will move backwards, and the wheels will rotate at twice the speed they normally would in response.

The. Plane. Will. Fly.

One final illustration for those who have difficulty understanding that the plane will fly because its motive force is independent of its relationship of its wheels to the ground.

Assume a HUMMER is parked on our imaginary runway. The runway is rigged to respond to the Hummer’s forward motion, by moving BACKWARDS at the same speed. You get in, and start the engine, and accelerate. As the wheels TURN to move the vehicle forward, the conveyor belt moves BACKWARDS at exactly the same speed. The net forward movement of the Hummer is ZERO. (At least to an independent observer standing off to the side. The speedometer will read acceleration to the driver.)

It is exactly like walking on a treadmill and having the tread mill match your speed. It is just like walking on an escalator, at the same speed, and standing still. Indeed, who among us has not done this? It is such a simple concept, that we are inclined to apply the same physics to our aircraft.

That would be a mistake.

For unlike the Hummer, or a Human on a treadmill or escalator, forward motion is NOT generated by exerting force against the ground, (And having the ground ‘push back’)

THAT IS THE FALACY in assuming it will stand still.

Now, back to the Hummer. It is still sitting on our runway, but this time we have modified it. We have disengaged the wheels from the engine completely. They are free to rotate. We HAVE modified the engine however, as we have connected it to a winch, mounted on the front of the vehicle. The winch is attached to a steel cable, a mile long. The other end of the cable is attached to a post, OUT BEYOND the end of the runway. It is not “connected” in any way to the surface of the runway.

The conveyor belt runway is still ‘rigged’ to move backwards at the same speed that the Hummer moves ‘forward’.

We start the engine, and engage the winch, which starts ‘winding’ the cable onto its drum, PULLING THE HUMMER FORWARD. (We also know that the engine, towline and winch are strong enough to tow the Hummer forward, because we have used them before, just as we know the engines of the aircraft are more than strong enough to generate speed for takeoff)


What does the conveyor belt do? Why, it’s rigged to move in the opposite direction… so it does that.

What do the WHEELS on the hummer do? Why they rotate, because they are free to do so, having been disengage from the drive train in any manner.

What does the HUMMER do? It moves forward, being ‘towed’ along by the cable attached to the drum. IF we ‘accelerate’ the winch, the Hummer’s forward motion will also accelerate.

In response, the conveyor also accelerates.

The wheels turn TWICE AS FAST as they normally would to an observer standing by the side of the conveyor belt runway.

The hummer MOVES FORWARD because the method of impulsion is not coupled to the interface between ground and tires. Even though the ENGINE for it’s movement is still attached to the Hummer’s body, it is applying a force that is NOT generated AGAINST THE GROUND (as it’s wheels were before.) It is independent of this.

Same thing would happen to our person in roller skates on a treadmill, holding a rope, and ‘pulling himself along’ by his arms. The roller skates would simply rotate at a speed that would appear to be ‘greater’ than the normal forward velocity, but there is nothing impeding his forward motion.

In the examples of the Hummer and the Human, the impulsion forces acting on the ‘bodies’ (fuselage, airframe) of both, are independent of the interface of the Hummer and Human with the treadmills. The impulsion force is independent of the speed of the Hummer’s wheels, or those of the Human’s roller skates.

When discussing the four factors affecting the airplane, LIFT, THUST, GRAVITY and DRAG, the only element that is being altered is DRAG. The drag of the runway AGAINST THE WHEELS. But the wheels are designed to rotate at ANY SPEED NECESSARY to facilitate a smooth interaction between the aircraft and the ground., and so eliminate, or minimize such a force. So they will simply rotate twice as fast as normal, and the plane will lift off.

The. Plane. Will. Fly.

Richard, the problem as posed introduces a feedback mechanism that causes the conveyer belt speed to match "the speed" of the airplane. I put the speed in quotes because the problem doesn't state how that speed is measured. If that speed is the forward speed of the aircraft, then my interpretation is correct. Aircraft speed is measure using an airspeed indicator and uses air pressure, not rotational speed of a wheel. If it is the wheel rotation, then you are closer to being correct, and good enough for a thought experiment.

I am a pilot, I know how airspeed is measured in flight, and the difference between airspeed and groundspeed.

The thought experiment postulates that as the aircraft moves forward, the conveyor belt moves 'backwards' matching its speed.

The 'apparent' speed of the aircraft to an observer standing off to the side of the runway/belt is a continual accelleration forward.

The 'apparent' speed of the aircraft in IAS (indicated airspeed) in the cockpit will be EXACTLY the same as if the aircraft were taking off from a stationary runwary. (Assuming still air.)

The 'apparent' ground speed, if reading off of a speedometer attached to the wheels, would indicate TWICE the apparent ground speed to an observer standing off to the side of conveyour belt.

The plane will fly, even if the conveyor belt is moving at twice or three times the speed of the aircraft.

The conveyor belts motion has very little effect on the aircraft's forard motion, it's main effect is the rotational speed of the wheels.

The Planes FORWARD motion is NOT offset by the conveyor belt/runway. The Planes ROTATIONAL WHEEL SPEED is. That is the only affect the belt has on the plane.

The. Plane. Will. Fly.

Oh good. Me too. We'll have to go flying sometime.

Good so far, but to make absolutely certain we agree on this point it is my understanding of the statement of the problem that the conveyer belt moves the AIRCRAFT backwards at a rate that instantaneously compensates for any detected forward movement of the aircraft as measured by the airspeed indicator. This implies that the ASI will always register 0.

This is incorrect, but irrelevant. The only thing that matters in this problem is the airspeed registered on the ASI, which you have established as 0.

I rescind my previous statement...at some point the bearings of the wheel would fail, connecting the airframe to the treadmill...then the treadmill would be pushing directly against the airframe and would also fail...with all the available pieces disconnecting the airframe from the ground, the airplane would melt into oblivion and not fly!

Okay, we're going to leave out bearings failing or tires blowing out, for the same reason we're going to leave out the pilot spilling coffee on his lap and hitting reverse thrust, or a flock of geese getting sucked into the engines.

Now, lets go back to the original stipulations of the thought experiement.

"If you have a large jet plane (747) sitting on a runway that was actually a giant conveyor belt (go with it). And there is also a device on the plane that communicates with the conveyor belt to tell it how fast the plane is traveling, which would then make the conveyor belt match the speed IN REVERSE."

The 'device' communicates with the conveyor belt to tell it how fast the plane is travelling.

Since the airspeed indicator is our 'speedometer' then it would be sending it's apparent airspeed to the conveyor belt.

The engines apply thrust.
The plane moves.
The airspeed indicator advances.
The belt moves backwards.
The wheels ROTATE at twice the speed they normally would.

The plane flies. The airspeed indicator would always read what it normally would at takeoff. (Assuming still air, as no head/tail/or crosswinds were stipulated.)

There is a curious effect, IF the 'device' measuring the planes 'speed' were NOT an airspeed indicator, but rather a speedometer attached to the wheels... such as in an automobile. (I've never flown a 747, only small single engine craft and sailplanes... NO engines! More fun..) then there would be a difference between the speed of the belt and the plane.

At any rate. IF the 'device' sensing the airplanes 'speed' WERE a speedometer sending it's speed to the runway, THEN the speed of the runway would NOT match the forward speed of the aircraft. It would ACCELLERATE at EXPONENTIAL rates. (The sensor in the wheel says it's moving at ten knots, the runway accellerates, the wheel rotates twice as fast, more accelleration, ETC... ALL INDEPENDENT OF THE AIRSPEED of the Jet through the air. As, indeed groundspeed is always independent of IAS or TAS)

At some point, would the bearings fail and the tires blow before the plane rotates? I don't know. But again, I don't know if the geese fly into the engine, the pilot spills his coffee, or the device that powers the runway/belt runs out of fuel... all irrelevant to the thought experiment.

The point is, the movement of the ground beneath the plane has no bearing on the planes forward movement through the air, even if the plane is trailing it's wheels on the ground. (Yes, yes, increased friction in the bearings, wear/tear on the tires aside please... the plane still moves forward.)


(Jim, please note that the thought experiment does not say the belt moves the airplane backwards. It says that the speed of the belt is set by the airplane, and that the belt moves 'in reverse'. I never said the airspeed would indicate 0)

If the conveyer belt does not move the airplane backwards at a rate that equally and instantaneously compensates for its forward motion then I agree with your analysis.

That's one heck of a very long conveyer belt by the way. Assuming it ain't a STOL aircraft...

The conveyor belt only moves 'in reverse' in response to the planes forward motion... being driven by the thrust of the engines. It cannot/does not/ move the plane backwards, or cause it to remain stationary.

And with that,

The earth IS round.

It revolves AROUND the sun.

Elvis is STILL dead.

The. Plane. Will. Fly.


I'm outahere....

Well, actually the earth is very close to, although not perfectly, spherical and it orbits around a mutual center of mass with the sun (and other masses wandering around the neighborhood).
:-)

But I do also really believe that Elvis is still dead...and earnestly hope this riddle and thread will be equally deceased!

I shoulda changed the topic of this thread to "OT: Any pilots here? ;) "

If Elvis is in the plane versus standing on the conver belt, the plane won't fly. It would ruin the thrust/weight ratio versus if he were standing on the belt which would slow the belt down, but have no effect on the friction in the planes wheel bearings thus reducing drag and rotational mass of the wheels because this time of year the earth is farthest from the sun keeping gravitational pull to a minimum allowing the planes wheels to spin at maximum thermal and frictional efficiency and allowing tire expansion to a maximum at higher speeds. Also note that cooler air tempatures produce more dense air and will produce more engine power, allowing the jets engines to overcome the weight of Elvis standing on the conveyer belt.

This Plane Won't Fly.

Adam, Adam , Adam,

If Elvis is on the plane...

It's ALREADY flying....

No way man, even with Elvis on the plane, the plane will fly.

The reason is down in the avionics bay underneath the cockpit is a Rockwell Automation Retro-Encabulator that not only provides inverse reactive current for use in unilateral phase detractors but is also capable of automatically synchronizing cardinal grammeters. Check it out for yourself:

http://video.google.com/videoplay?do...89882805593268

Case closed. This baby is going to fly.