will it take off?

[RayH]

It all comes down to the no-fly crowd either ignoring the thrust being developed by the engine or specifying a massive amount of friction that would soak up that thrust.

Harry K

I vote this whole thread be put to bed.

I dont think they are "ignoring" the thrust. I think they are confusing ground speed and air speed and how the engine thrust related to them.
I cant put it to bed until EVERYONE is on board.

 

[RayH]

Hmmmnnnn a horribly revolting thought just came to me. what is this were a float plane and it was in a river and the river could match the speed of the plane?

Doesnt change a thing.

 

[jk96]

I couldn't help myself, I had to throw in one more of my wonderful art exhibits before it gets put to rest?


Would you stand here when they lit this puppy up? lol
Not if your in the "will fly" crowd.

jk

 

[RayH]

A quote from the original question: "the conveyor has a system that tracks the speed of the plane and matches it"

I would still like someone to explain to me how the plane can sit still, yet the conveyor moves? Ive asked a few times in this thread and I dont think anyone has answered it.
I think this question needs to be answered if the "no flys" are to see the error of their ways.

 

[Paddy]

Patrick G,

You have to get over the plane remains stationary idea. That is the trick. The problem needs to be revisited. "As the plane moves....." You are still thinking wheel speed. The convayor is matching the plane speed, not the wheels. This convayor does not require magic to match plane speed. It might to match WHEEL speed. I agree, All this talk of speed of light and wheel chalks are irrelevent. All you need is a convayor to move at 50 mi so the plane can perform in the oposite direction at 50 mi to lift off. The MCB does not need high acceleration either. The plane could slowly ramp up speed, but when it reaches lift off speed, she flys. So I don't get where magic is needed other than some having to build this contraption to show the non-believers they read the problem wrong. This whole silly puzzle could have been settled if the first point of matching wheel speed vs plane speed was settled.

Your point of the convayor catching enough wind to provide lift has little merit because the above points

 

[Paddy]

Ray,

There have several of us who have asked the question of moving/not moving and speed of wheels vs speed of plane. No one address it. It always fall back to wheels spinning at infinite speeds

 

[TomKioti]

You can draw all the stick drawings you can produce and while you're at it throw in the grassy nole argument stick figures and the Jimmy Hoffa whereabout maps along with the 911 conspiricy instructions along with it. Patrick G is right. You all are confusing the argument. One more time.

If the planes mass (wings and all) does not expierence the forward movement and associated air to produce lift and the treadmill effectively nulls that forward thrust the plane is producing, then the plane is not going to become airborne. That mass (the plane) has to physically move thru the air to introduce all the properties required for lift. MYTH STILL BUSTED UNTIL I SEE IT IN PERSON!!!! Then I will buy all of you a happy meal if my wife says it's ok
Tom K

 

[RayH]

Ray,

There have several of us who have asked the question of moving/not moving and speed of wheels vs speed of plane. No one address it. It always fall back to wheels spinning at infinite speeds

Wheels spinning at infinate speed if the wheel speed is what the question means by "match the speed of the plane".
If the question actually means for the conveyor to match the speed of the whole plane, then the wheels will only be going twice as fast as takeoff speed and the conveyor would be going the same speed as the plane (as per the question)

 

[Steve_Miller]

Now I am getting really confused!

I beleive someone indicated lift would created by air flowing over the wings.

Well, today I drove to Halifax and back with lots of air flowing over the right and left wings of my truck. Even at speeds in slight excess of the posted limit I did not notice any lift occuring.

I've gotta see a picture of this truck, maybe we can give you some insight on how large the wings will have to be to achieve liftoff.

Steve

 

[TomKioti]

Egon,

So.... your truck has wings?

 

[RayH]

If the planes mass (wings and all) does not expierence the forward movement and associated air to produce lift and the treadmill effectively nulls that forward thrust the plane is producing, then the plane is not going to become airborne. That mass (the plane) has to physically move thru the air to introduce all the properties required for lift. MYTH STILL BUSTED UNTIL I SEE IT IN PERSON!!!! Then I will buy all of you a happy meal if my wife says it's ok
Tom K

The MCB does not nulify the thrust of the engine. All it nulifies is the forward motion of the wheels.
Equal and opposite reaction problem:
The wheels roll forward = the treadmill rolls backward. These two thing are equal, the plane sits still.
The prop produces thrust = ?, With nothing to equal the thrust, the plane has to move forward. With the engine off, there is no thrust, the plane obviously sits still. If you add thrust, it has to move.
Keep in mind that if (when) the plane rolls, the wheels and MCB are still offsetting but the added thrust from the engine causes the unbalance and the plane moves. If the engine quites, the plane will roll to a stop and all will be equal again.

Try this analogy. Lets put the MCB of a hill, with the plane facing down hill. Now gravity replaces engine thrust. Will the plane start rolling down hill when the brakes are released and the conveyor will starts moving backwards to match the planes speed. Do you think the plane will stay in one place on the hill or will gravity cause it to roll down the MCB?

Think about a toy airplane on a supermarket checkout conveyor. When you hold the toy still on the moving conveyor, the action and reaction are equal. If you pull or push the toy forward, the actions are now unequal and it will move forward. Now the clerk hits the turbo on the conveyor and it speeds up. You can still push the toy forward just as easy as you could before, right. The only thing that has changed is how fast the wheels are spinning.

 

[jk96]

Ray,

Excelent examples but I'm not sure it will make any difference. I chatted back and forth a few times last night with someone on the Mythbusters forum. They had the same debate a while back...50+pages as well. While many of the people on the forum finally got it, there were still a few holdouts that could not see how the plane would fly if God himself showed them.

I also used the example of an Remote Control airplane on a treadmill that moved faster than the plane was capable of flying. The plane will move up the treadmill and excellerate, but somehow no one seems to believe this is possible.

jk

 

[RayH]

Ray,

Excelent examples but I'm not sure it will make any difference. I chatted back and forth a few times last night with someone on the Mythbusters forum. They had the same debate a while back...50+pages as well. While many of the people on the forum finally got it, there were still a few holdouts that could not see how the plane would fly if God himself showed them.

I also used the example of an Remote Control airplane on a treadmill that moved faster than the plane was capable of flying. The plane will move up the treadmill and excellerate, but somehow no one seems to believe this is possible.

jk

I know. Im baffled.
I like this thread though because it makes me feel smarter than the average bear.

 

[jk96]

Hey Ray,

Here's one more for you. Try telling someone at Boeing who tests their high powered jet engines that they don't need to go through all the trouble of anchoring them down anymore when applying full thrust in the testing lab. Just put them on a set of wheels and fast moving treadmill.

jk

 

[TomKioti]

The MCB does not nulify the thrust of the engine. All it nulifies is the forward motion of the wheels.
Equal and opposite reaction problem:
The wheels roll forward = the treadmill rolls backward. These two thing are equal, the plane sits still.
The prop produces thrust = ?, With nothing to equal the thrust, the plane has to move forward. With the engine off, there is no thrust, the plane obviously sits still. If you add thrust, it has to move.
Keep in mind that if (when) the plane rolls, the wheels and MCB are still offsetting but the added thrust from the engine causes the unbalance and the plane moves. If the engine quites, the plane will roll to a stop and all will be equal again.

Try this analogy. Lets put the MCB of a hill, with the plane facing down hill. Now gravity replaces engine thrust. Will the plane start rolling down hill when the brakes are released and the conveyor will starts moving backwards to match the planes speed. Do you think the plane will stay in one place on the hill or will gravity cause it to roll down the MCB?

Think about a toy airplane on a supermarket checkout conveyor. When you hold the toy still on the moving conveyor, the action and reaction are equal. If you pull or push the toy forward, the actions are now unequal and it will move forward. Now the clerk hits the turbo on the conveyor and it speeds up. You can still push the toy forward just as easy as you could before, right. The only thing that has changed is how fast the wheels are spinning.

I said nothing of the wheels (however they are conected to the plane), forget the wheels. I said if the phantom treadmill NEGATES AND MATCHES the FORWARD THRUST AND MOVEMENT of the aircraft then effectively there would be no mass (big jet) actually moving. Hence no flight properties would exist. MYTH STILL BUSTED AND WIFE SAYS NO DAGGON HAPPY MEALS AND TAKE OUT THE GARBAGE!!! Sorry folks.

 

[RayH]

Hey Ray,

Here's one more for you. Try telling someone at Boeing who tests their high powered jet engines that they don't need to go through all the trouble of anchoring them down anymore when applying full thrust in the testing lab. Just put them on a set of wheels and fast moving treadmill.

jk

When I went to A&P school a number of years ago. We had a Jet engine from a 104 Starfighter, It was a GE J something (I dont recall the number). This engine was used just to train students how to run up and test jet engines. We bolted it to a stand and then chained the stand to the ground. We then went into a concrete block booth with a 1" thick plexiglass window, about 20' from the engine, to run the engine up to full power. That engine would shake the concrete block, it would shake the ground, you could feel the plexiglass bending and flexing. The engine would move around as it pulled at the chains, it actually looked like it lifted off the ground at times. The amount of power really was amazing and that was an ancient engine, lame by todays standards, with who knows how many hours on it.
Ive also run up an unknown number of recip prop engines from a control booth mounted directly behind the engine. Lots of air being blasted back. The recip booths also have to be tied down. Anyone who has done this, would realize that a simple MCB isnt going to stop the prop from pulling the plane.

 

[TomKioti]

Hey Ray,

Here's one more for you. Try telling someone at Boeing who tests their high powered jet engines that they don't need to go through all the trouble of anchoring them down anymore when applying full thrust in the testing lab. Just put them on a set of wheels and fast moving treadmill.

jk

UUH... Like that's an anology for our discussion. C'mon dude. Stick to the anchors of the debate.

 

[jk96]

From the original post

"as the plane moves the conveyor moves but in the opposite direction.the conveyor has a system that tracks the speed of the plane and matches it exactly in the opposite direction"

Again, if the plane is going 200 mph forward, the conveyor is going 200 mph backwards. Nothing to negate the force of the engine thrust.

jk

 

[TomKioti]

Ray,

Excelent examples but I'm not sure it will make any difference. I chatted back and forth a few times last night with someone on the Mythbusters forum. They had the same debate a while back...50+pages as well. While many of the people on the forum finally got it, there were still a few holdouts that could not see how the plane would fly if God himself showed them.

I also used the example of an Remote Control airplane on a treadmill that moved faster than the plane was capable of flying. The plane will move up the treadmill and excellerate, but somehow no one seems to believe this is possible.

jk

I'm not from the show me state but SHOW ME!

 

[RayH]

I said nothing of the wheels (however they are conected to the plane), forget the wheels. I said if the phantom treadmill NEGATES AND MATCHES the FORWARD THRUST AND MOVEMENT of the aircraft then effectively there would be no mass (big jet) actually moving. Hence no flight properties would exist. MYTH STILL BUSTED AND WIFE SAYS NO DAGGON HAPPY MEALS AND TAKE OUT THE GARBAGE!!! Sorry folks.

Can you comment on my examples of the MCB on an incline and the supermarket conveyor?
Try to convince me that the plane will not roll down hill if placed on the MCB. Or that you will not be able to push a toy plane on the supermarket conveyor.