will it take off?

[N80]

I'll admit that I haven't read the last six pages of this mental self flagellation...if you get my drift, but if we can believe that a pretend conveyor belt can be that big and fast, why bother with the pretend plane and just ride the pretend conveyor belt?

And if a car is moving at the speed of light and turns its headlights on, do they do anything?

What hits the ground first, the bullet shot from a level gun barrel five feet off the ground or a bullet dropped straight down from five feet at the exact same time the other bullet leaves the barrel.

These two alone should be worth another 20 pages!

 

[roermo]

I think I see a myth buster show for this thread in the furture

roger

 

[RayH]

And if a car is moving at the speed of light and turns its headlights on, do they do anything?

What hits the ground first, the bullet shot from a level gun barrel five feet off the ground or a bullet dropped straight down from five feet at the exact same time the other bullet leaves the barrel.

The headlights will shine normally and the dropped bullet will hit the ground first.

Newton says the bullets hit at the same time but he didnt take into consideration that the bullet is spinning. That keeps it on a flatter trajectory through spin stabilization

 

[Egon]

http://http://oceanlink.island.net/oinfo/biodiversity/flyingfish/flyingfish.html


Flying fish!

Strap enough Jato bottles at the right angle on to the aircraft and touch em all off at the same time and you should get "Lift Off"

 

[Richard]

Time to show off my level of ignorance...

If the plane is sitting STILL on said conveyor the weight of the plane is on the wheels, right?

The plane can't take off until said weight is transferred to the wings, right?

Seems to me that transition is made during the process of takeoff as the plane speeds through the air, creating lift over the wings.

Since the plane has all its forward motion nullified by the reverse motion of the conveyor, how, where and when, does the plane garner the forward airspeed to transfer said weight onto the wings & take off?

Who ever created this thread needs to be tarred & feathered!!

 

[BillyP]

I done a lot of thinking on this yesterday. I'm the first to admit I'm a little slow but that dang plane will fly.

All you non believers, put your imagining hats on now and follow me.

You have said plane and said conveyor but for this demonstration we need one more item. We build a human runway above the plane and next to the tail (the part that sticks up).

You get on the runway, the pilot starts the engine, throttles up and you start pushing the plane forward by it's tail. You're a very strong (Incredible Hulk) person. You push the plane forward faster and faster. You know the plane is moving forward because you are. You go faster and faster. You feel the wind in your face getting stronger (wind speed). Right at the end of 'your' runway you are running at 80 MPH and the plane leaves the ground.

In conclusion I've finally been able to separate the plane's wheels and the conveyor from the real story. As said many times before, in the thread, the plane's wheels and the conveyor are a none issue. I just had to get it straight in my mind.

 

[dillo99]

Wow...interesting stuff. I am amazed that there is such STRONG conviction on either side of the argument. Every is convinced they are correct - which makes this more interesting. Just to weigh in here:

I think everyone agrees that this plane (assuming a typical plane) must have forward motion to take off - so the question is...can it move.

If the magic conveyor truly matches the speed of the wheels there will be no forward motion of the plane = no flight. I understand what people are saying about the wheels not driving the plane - the prop does - but the wheels still represent the speed of the plane relative to the ground. So if the prop gets the speed to 60mph the conveyor is going to magically make that zero mph by moving in the opposite direction. So no matter what the prop does, it can't move the plane until it can separate the plane from the magic conveyor (which it can't do).

No forward motion = no lift off

 

[NewToy]

What is the winch in your example attached to? Something that is attached to the same ground that the treadmill is sitting on, that's what. A winch attached to the ground is not the same things as air flowing over that ground.

I believe that the perfect magic treadmill (if it existed) that could exactly counteract the wheel's rotation from the instant it tried to roll would act just like a rope tied to the plane's tail and keep it from moving. The airplane would just be a big fan blowing air behind it, anchored to the treadmill by the friction between the tires and the surface of the treadmill.

To be honest, the entire scenario is not possible, because a treadmill that can exactly counter the wheel's movement does not and cannot exist. It would have to intuitively know when to turn BEFORE the wheel ever turned, otherwise it would be a reaction, not an action.

I believe with sophisticated controls and computers monitoring the plane the scenario would be very possible. Let's pool all of our money and commission JPL to build us the perfect treadmill so we can put this to bed.

The winch is attached to a FIXED point on the ground just in front of the treadmill. When engaged the winch would pull the plane forward regardless what the conveyor is doing. The result would be the wheels on the gear doing 2x the speed that the plane is moving forward. The propeller is spinning in fixed air not attached to the treadmill resulting in the plane moving forward with the wheels doing 2x with the conveyor in the opposite direction. The thrust created by the prop is the same thing as a cable as the prop pulls it's way through the viscous atmosphere the plane has to move forward. It will eventually come to you when you get around your fixation on the conveyor that really has nothing to do with the plane moving forward. The plane will fly!

Pick up a few Stephen Hawking or Michio Kaku books and really read them. They will help you look at things from outside the box. They have some ideas about our existance and surroundings that really get you thinking.

Like you said, the plane will be generating thrust in a rearward direction resulting in an equal and opposite reaction, (Plane goes forward). I don't understand how you think the "friction" in the wheel bearings and tires could negate all the thrust the engine generates. The plane would take a tiny bit longer to achieve liftoff on the treadmill because of the friction you spoke of and the energy burned up with the wheels turning 2x due to the opposing force of the treadmill. You can't see "Thrust" but it will exert the same force on the plane as a cable that you can see.

I am positive the plane will move forward relative to the ground and FLY! It is mandated by the laws of physics, no way around iy.

John

John

 

[dillo99]

The winch is attached to a FIXED point on the ground just in front of the treadmill.

Which makes the winch example NOT comparable to the propeller example. I agree in your scenario, the plane would fly - because it is impossible for the conveyor to make the speed of the plane zero. The winch is moving the cable so the plane HAS to move. Your example basically makes the magic conveyor null and void - it can't eliminate ground speed because the fact that the cable is shortening will mean that it can't match the speed of the planes wheels (would require the laws of physics to change)

In the propeller example, this is not necessarily true. Since the wheels represent the ground speed and since the magic conveyor is countering all ground speed, the plane is not moving. No movement = no flight

 

[turnkey4099]

Ray
The answer is yes. We transmit between ground and planes or between planes at the speed of lignt, not the speed of sound.

And to add to that. The radio the airplane is using is traveling at 0 velocity in relation to the pilot/passengers.

Harry K