will it take off?

[RayH]

I keep trying to find ways to explain that the plane will fly but its mostly been covered.
I think everyone agrees that if the plane moves forward it will have lift and eventually take off. If anyone doesnt get that concept they are beyond help on the rest of this.
I think everyone gets that the wheels do not push it forward, the prop pulls the plane.
I think the problem is trying to convince people that the prop is going to pull the plane no matter what the conveyor is doing. As long as the prop is pulling the plane, its moving forward therefore creating lift. How do you convince people that the prop doesnt stop pulling air just because the wheels are spinning and the speed they are spinning doesnt effect how much air the prop pulls through it..

 

[Duke4AZ]

Please, put this thread out of its misery. The statement is, ". . . as the plane moves . . . " meaning that the plane has forward motion. That motion is a result of thrust due to the propeller, the turbofan or the turbotjet, NOT THE LANDING GEAR. That statememt alone means that the plane is not standing still. As such there is air flowing over the wings. Now, since there is no statement that says there is any abnormal influence on a plane being propelled by its thrust system the assumption is that it is able to reach a "forward motion" capable of establishing the lift necessary to get the thing off the goofy conver belt that happens to be running the landing gear at twice the air speed . . . assuming there is absolutely no wind in either the head or tail direction. As such the plane is going to take off. If anyone has any questions on that, just read Jeff's from NY or Bill the Marine's explaination. Both are dead on and are absolutely correct.

Please, either add something new to this thread about how to get a tractor to fly or just let it die the old age death of a perfectly enjoyable forum discussion that has run its course.

Duke
Aerospace Engineer / Grading Equipment Owner/Operator Wannabee

Oh, and the balls will stop because the coefficient of resititution is less than 1.0 and efficiency due to alignement with a only a very tiny affect due to air resistance.

 

[MossRoad]

Nope, the wheels can't turn faster than the conveyor because the conveyor kicks into turbo boost overdrive and keeps up.

And the tires are made of a super non skid resistant high performance guaranteed to have 100% traction Firestone 500 Finger Plus and made especially for model airplanes on a super responsive magical conveyor belt

Oh. Well, then. I didn't know they had THOSE tires. (creeps away sheepishly)

 

[MossRoad]

MossRoad, You seemed to be stuck on the conveyor matching the speed of the wheels when the scenario states that the conveyor matches the speed of the plane. Splain that one.

O.K. I'll try.

1. Put airplane on a conveyor.
2. If it goes backwards it is moving slower than the conveyor, yes?
3. If it stays in the same place it is going the same speed as the conveyor, yes?
4. If it moves forwards it is going faster than the conveyor, yes?

Therefore, if it moves faster than the speed of the conveyor it did not adhere to the rules set by the original problem, did it? No.

Now everyone say, "Thanks Mr. Obvious!"

Hehehehehehee

 

[MossRoad]

I keep trying to find ways to explain that the plane will fly but its mostly been covered.
I think everyone agrees that if the plane moves forward it will have lift and eventually take off. If anyone doesnt get that concept they are beyond help on the rest of this.
I think everyone gets that the wheels do not push it forward, the prop pulls the plane.
I think the problem is trying to convince people that the prop is going to pull the plane no matter what the conveyor is doing. As long as the prop is pulling the plane, its moving forward therefore creating lift. How do you convince people that the prop doesnt stop pulling air just because the wheels are spinning and the speed they are spinning doesnt effect how much air the prop pulls through it..

I think everyone agrees with you that IF the plane moves forward it will have lift and eventually take off.

What a lot of folks in the no fly camp are thinking is the plane won't ever get to move forward in the first place because of the rules of the conveyor belt being it has to match the speed of the plane, not go slower than the plane. It has to go slower than the plane in order for the plane to move forward. Those are the laws of nature, too.

 

[shaley]

So is it correct to say that if there is any friction in the wheels or the A/C has skids rather than wheels this conveyor will be able to hold the plane back until the thrust force overcomes the rearward drag force.

 

[NewToy]

I think everyone agrees with you that IF the plane moves forward it will have lift and eventually take off.

What a lot of folks in the no fly camp are thinking is the plane won't ever get to move forward in the first place because of the rules of the conveyor belt being it has to match the speed of the plane, not go slower than the plane. It has to go slower than the plane in order for the plane to move forward. Those are the laws of nature, too.

If the conveyor is matching the speed of the plane, by default the plane must be moving forward. If the plane moves forward it flies. The wheels of the plane are spinning 2x the speed of the plane at liftoff. SO SIMPLE!

 

[rback33]

Wow... did you guys do ANYTHING over the weekend? LMAO I thought there would be a few replies, but not several PAGES of replies... Has this thread set any records yet? If not how much further to go? Quite frankly the subject has begun to make my head hurt.

 

[MossRoad]

If the conveyor is matching the speed of the plane, by default the plane must be moving forward. If the plane moves forward it flies. The wheels of the plane are spinning 2x the speed of the plane at liftoff. SO SIMPLE!

Yes, it is simple. If something is moving forward on a conveyor running in the opposite direction it must be going faster than the conveyor, not the same speed as the conveyor.

 

[MossRoad]

Wow... did you guys do ANYTHING over the weekend? LMAO I thought there would be a few replies, but not several PAGES of replies... Has this thread set any records yet? If not how much further to go? Quite frankly the subject has begun to make my head hurt.

Yes. I asked my wife, who works with numbers her whole life, to develop an algorithym to explain if this could work or not. She said that no matter how fast that propeller turned, whether the conveyor matched the speed from a dead standstill or from a rolling start, no matter what the airspeed, groundspeed or anything, the basement won't clean itself.

 

[rback33]

Yes. I asked my wife, who works with numbers her whole life, to develop an algorithym to explain if this could work or not. She said that no matter how fast that propeller turned, whether the conveyor matched the speed from a dead standstill or from a rolling start, no matter what the airspeed, groundspeed or anything, the basement won't clean itself.

*LMAO* Sounds like my house.. except no matter how many cups of tea I make my wife.. her clean laundry is STILL in a pile at the foot of the bed... On the bright side... REALLY slow dial up is our only (affordable) option at home, so I don't usually get to obsess here on weekends. Seeing how this thread mushroomed over the weekend I consider myself blessed!

 

[turnkey4099]

Yes, I agree that the plane needs airspeed and not ground speed to take off and yes I understand that the wheels are not a source of thrust - they have nothing to do with POWERING the plane to take off. BUT the wheels do represent the speed of the plane while it is on the ground. So if the wheel is turning 5 rotations per second then the plane is moving forward at 5 rotations per second. If, you somehow magically counter that and move the plane backwards at an identical rate (5 rotations per second) then you effectively cancel out any movement of the plane. It is not moving. Yes, the propeller provided thrust to move it forward, but the ground moved the plane backwards an equal distance thus taking airspeed to zero.

To me, the conveyor is identical to the scenario of the brakes being locked. If the breaks are locked and thus the plane does not move, can it take off? No because it can't generate air speed. You point out that "all the wheels do is allow the plane to travel at the speed of the prop" - AGREED. And in this case, I interpret the conveyor to be preventing that movement. I guess it depends on your interpretation of the conveyor. If it truly can match the speed of the wheels instantly, then to me it is the same as the wheels not spinning which is the same as the brake being on. no movement = no airspeed = no flight

What you fail to see is that the airframe does not contact the conveyor in any way. Only the wheels do. Only if the bearings lock up or brakes applied does the airframe -care- what the wheels are doing. It can't even tell that the wheels are turning. As long as the engine is powerful enough to overcome any friction, the wheels can turn 10x forward, 10x reverse or at 0 speed and the plane _will_ move forward. The airframe also doesn't sense any of the conveyor, all it is seeing is airspeed over it's shape.

Harry K

 

[turnkey4099]

Trying a different way since you seem hung up on the wheels having an effect on the planes motion.

Take two converyors at right angles.

One points in the direction of the plane and is infinite in length. The airplane is tethered to it.

The second is at right angle, rests on and is fixed to the first conveyor. This one only needs to be a short one. It is set up so that as air speed increases, so does the conveyor speed. The plane is placed on the second coveyor with the wheels turned at right angles to the plane (lined up with the second coveyor.

Clearly the plane can take off and the wheels can rotate at any speed from 0 to infinity with no effect on the air frame. Now you can postulate that friction from bearings will try to drag the plane sideways but these are the ideal, frictionless bearings.

That is the same situation as the first one. Speed of the wheels has nothing to do with air speed.

Harry K

 

[755inNY]

O.K. I'll try.

1. Put airplane on a conveyor.
2. If it goes backwards it is moving slower than the conveyor, yes?
3. If it stays in the same place it is going the same speed as the conveyor, yes?
4. If it moves forwards it is going faster than the conveyor, yes?

Therefore, if it moves faster than the speed of the conveyor it did not adhere to the rules set by the original problem, did it? No.

Now everyone say, "Thanks Mr. Obvious!"

Hehehehehehee

If the plane stays in the same place, its speed is ZERO.

What are you using as a reference point for the speed of the conveyor and the speed of the plane?

 

[NewToy]

O.K. I'll try.

1. Put airplane on a conveyor.
2. If it goes backwards it is moving slower than the conveyor, yes?
3. If it stays in the same place it is going the same speed as the conveyor, yes?
4. If it moves forwards it is going faster than the conveyor, yes?

Therefore, if it moves faster than the speed of the conveyor it did not adhere to the rules set by the original problem, did it? No.

Now everyone say, "Thanks Mr. Obvious!"

Hehehehehehee

Mr. Obvious, What you fail to understand is the plane's wheels spin freely and have nothing at all to do with propelling the plane forward. Accept it, it flies. Your line of reasoning applies to something that uses the wheels as the propulsion, car, TRACTOR, etc. It will eventually come to you. Keep working on it.

 

[JimParker]

Moderator - I'm begging you: Please close this thread!

 

[BTDT]

I don't think they are home. I have been waiting a week or more about some photo posting problems, no answer. They may be working part time at the print shop making bumper stickers for the 1,000,000th post giveaway.

 

[rutwad]

First post on this thread, and first day spent scanning several posts. Haven't completely kept up, but

THE PLANE WILL FLY!!!

Has anybody come up with a final total, believers vs. not believers.



If object A is travelling toward object B and when it reaches the halfway point it slows to half it's speed, will it ever reach object B?

If the earth stopped spinning, would we all be killed by the severe force of gravity?

If a scientist views an object that is 90,000 light years away, then can we say that object still exist or is he seeing what is was 90,000 years ago.

 

[NewToy]

First post on this thread, and first day spent scanning several posts. Haven't completely kept up, but

THE PLANE WILL FLY!!!

Has anybody come up with a final total, believers vs. not believers.



If object A is travelling toward object B and when it reaches the halfway point it slows to half it's speed, will it ever reach object B?

If the earth stopped spinning, would we all be killed by the severe force of gravity?

If a scientist views an object that is 90,000 light years away, then can we say that object still exist or is he seeing what is was 90,000 years ago.

1) Is object B stationary? If so "A" takes twice as long to get there. If moving at same speed, it never catches up.
2) Not if you were on the aforementioned treadmill.
3) He can't know for sure if it is still there or not. He is indeed looking into the past.
If the sun were to magically vanish it would take 8 minutes or so for us to notice since the light takes that long to get here. How long would it take for the planet to careen off into space from the loss of the sun's gravitational hold on us?

 

[bx23barry]

The wheels or the belt/conveyor have nothing to do with the plane moving. It will take off the same as not being on the belt.