will it take off?

[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.