A quick recap is in place:
Only one thing, the plane would never lift off! When you are convinced that this is right, I will convince you of the opposite 😀
Steen😎
What do you think from this??
Only one thing, the plane would never lift off! When you are convinced that this is right, I will convince you of the opposite 😀
Steen😎
I come back red faced. Please forgive. While I was off on my tangent about air flow, the decoupling of the wheels from the engine somehow escaped me.
Don't worry, I've slapped myself a few times.
So how fast are the wheels turning at takeoff speed?
Don't worry, I've slapped myself a few times.
So how fast are the wheels turning at takeoff speed?
eVITAERC said:
Neither Cal nor Carl is my legal name. it's just what i like to be called. And the last name, I won't really go into except to let you know it's how my parents encouraged me when I was a child. I didn't want to spell it any more obviously 😀
eVITAERC said:
None of the above is relevant. The conveyor belt is simply not in a position to do what you ask of it. It can do no more than turn the wheels. And the wheels are decoupled from the plane by the axle. In a nutshell, the plane and the wheels are free to act independently to the relevant stimulus.
But the plane would have problems if that happened. I think that no matter what, we have to assume that nothing breaks, so there are no limits either to the amount of power the wheels can waste, or how much thrust the engines can produce before they tear off and fly away on their own.rfbrw said:
Depends on which interpretation. The one which is presumably supposed to be the correct one (the conveyor belt moves forward at a speed equal to the plane, relative to the ground) then the wheels never rotate at all. If you instead interpret it as the conveyor belt moving backwards to prevent the wheels moving relative to the ground, then they will have to rotate infinitely fast.Cal Weldon said:
My gosh this is fun.
Okay, let's look at the last bit.
-Chris
Okay, let's look at the last bit.
ie, the wheels do not rotate. Have I missed anything? To keep the wheels from moving forward against the force applied by the engine(s) against the air, the belt must move in the direction of the body of the airplane. Dynamically keeping the wheels from moving. The actual movement will be small because every servo must operate with some error. Doesn't matter, airplane has reached rotation and leaves the conveyer. In flight. Bye bye.
-Chris
rfbrw said:
I fail to see how there is no analogy between the plane running on a rotating object (the earth) and the plane running on another rotating object (the conveyer). In both cases the mecahnics driving the plane, including all the nitty-gritty "fairy tale physics" about how the wheel is somehow decoupled from the engine in a kinematical sense, is voided because the mechanics of the plane stayed the same. I simply swiched the earth for the conveyer belt, Indiana Jones style.
If the first scenerio (earth) seems plausible to you, there's no reason why the second scenario (conveyer) shouldn't.
Hey look~ The sanding sealer on my new cabs dried 😀 I can get back to working on it now ^^
Also, if we intrepret the question as the wheels not rotating, then the plane definately will take off. End of discussion.
to all u non believers
imagine ice instead of wheels , it that case , whats gonna stop the plain?
imagine ice instead of wheels , it that case , whats gonna stop the plain?
Hi eVITAERC,
In the first case the air is moving with the earth and the engines are acting on the air. In the second case the air is not greatly influenced by the conveyer belt so the motion of the plane and the surface are not related.
'Tis the air and the plane you need to worry about.
-Chris
In the first case the air is moving with the earth and the engines are acting on the air. In the second case the air is not greatly influenced by the conveyer belt so the motion of the plane and the surface are not related.
'Tis the air and the plane you need to worry about.
-Chris
Hi sss,
Salt. In Canada we use salt on the ice to stop cars from sliding. Sand might work too. 😉
-Chris
Salt. In Canada we use salt on the ice to stop cars from sliding. Sand might work too. 😉
-Chris
Mr Evil said:
In that case, the plane will always take off
eVITAERC said:
Ask yourself this. In the normal course of events, does a plane go forward because the wheels are turning or are the wheels turning because the plane is going forward?
anatech said:
😀 😀 😀
i' triying to help the non believers to understand that the plain will take off
just like those plains on water , no wheels and woooo take off
wheel spin is not important in that situation , they are there to insure free movement of the plain and to brake it while landing , thats all
To fly, or not to fly, that is the question.
Hi to all you aircraft enthusiasts.
Pinkmouse is quite correct, as the ground speed (or the surface movement of the ground relative to the plane's position, which is all that is out of the ordinary in this case) has nothing to do with lift, which is what governs the plane's ability to take off (under all other 'normal' circumstances).
Lift is created when the surrounding air flows past the plane's wings, and this lift can be aided to some extent by wind blowing from the front of the plane backwards, or partly countered when the wind blows from the back of the plane forwards.
Indeed, I once saw a Tiger Moth (a quite lightly built canvas covered bi-plane, and ex-WW2 trainer) being tied down to the ground to prevent it from taking off whilst it was completely stationary (relative to the ground) because this plane's stalling speed was only approx. 75 MPH, and the wind was blowing past it from the front at about this speed!
For those who are not aware, the stalling speed of an aircraft is basically the minimum speed it needs to maintain in relation to **the surrounding air**, in order to stop it falling out of the sky.
Also on some of the very early aircraft carriers and with these old lightweight planes, they could actually land moving backwards relative to the ship because the ship's forward motion when added to a strong head-on wind, also exceeded the plane's stalling speed! Nowadays, and with much heavier planes, considerably higher stalling speeds apply.
With any conventional fixed-wing plane, there should be quite sufficient forward thrust to propel the plane through the air **in which it currently resides** (irrespective of the ground's relative position, or movement) and this is the crux of the matter if it is to take off. Also, unless there is something wrong with the landing gear, this will have no bearing on the issue, since as others have tried to point out, the forward thrust is not provided through its wheels, but by the engines (propellor or jet) forcing air backwards. The wheels will rotate quite happily, if necessary, either forwards or backwards, and at any (sane!) speed, unless someone puts the brakes on.
Finally, if there is any lift also being provided by the plane's engines encouraging air to flow past the wings, as some posters appear to think, this is more by accident than design, especially as most jet engines' exits (for example) are not in front of the main wings, anyway, and this would have more effect on the tailplane, if anywhere at all.
I hope this helps to clarify the position.
Bob.
Hi to all you aircraft enthusiasts.
Pinkmouse is quite correct, as the ground speed (or the surface movement of the ground relative to the plane's position, which is all that is out of the ordinary in this case) has nothing to do with lift, which is what governs the plane's ability to take off (under all other 'normal' circumstances).
Lift is created when the surrounding air flows past the plane's wings, and this lift can be aided to some extent by wind blowing from the front of the plane backwards, or partly countered when the wind blows from the back of the plane forwards.
Indeed, I once saw a Tiger Moth (a quite lightly built canvas covered bi-plane, and ex-WW2 trainer) being tied down to the ground to prevent it from taking off whilst it was completely stationary (relative to the ground) because this plane's stalling speed was only approx. 75 MPH, and the wind was blowing past it from the front at about this speed!
For those who are not aware, the stalling speed of an aircraft is basically the minimum speed it needs to maintain in relation to **the surrounding air**, in order to stop it falling out of the sky.
Also on some of the very early aircraft carriers and with these old lightweight planes, they could actually land moving backwards relative to the ship because the ship's forward motion when added to a strong head-on wind, also exceeded the plane's stalling speed! Nowadays, and with much heavier planes, considerably higher stalling speeds apply.
With any conventional fixed-wing plane, there should be quite sufficient forward thrust to propel the plane through the air **in which it currently resides** (irrespective of the ground's relative position, or movement) and this is the crux of the matter if it is to take off. Also, unless there is something wrong with the landing gear, this will have no bearing on the issue, since as others have tried to point out, the forward thrust is not provided through its wheels, but by the engines (propellor or jet) forcing air backwards. The wheels will rotate quite happily, if necessary, either forwards or backwards, and at any (sane!) speed, unless someone puts the brakes on.
Finally, if there is any lift also being provided by the plane's engines encouraging air to flow past the wings, as some posters appear to think, this is more by accident than design, especially as most jet engines' exits (for example) are not in front of the main wings, anyway, and this would have more effect on the tailplane, if anywhere at all.
I hope this helps to clarify the position.
Bob.
Hi sss,
Well .... you did ask ..... I was compelled to give you an answer.
Hi rfbrw,
If you stopped watching our politicians you'd see that some things do work in Canada. 😀 Besides, it's not that cold here - except today.
-Chris
Well .... you did ask ..... I was compelled to give you an answer.
Hi rfbrw,
If you stopped watching our politicians you'd see that some things do work in Canada. 😀 Besides, it's not that cold here - except today.
-Chris
Yes. The statement is ambiguous. The wheels' rotation is, well, a rotation, but the conveyor belt's surface is moving linearly, thus whether or not they are moving in the same direction depends on which point of the wheel you are looking at, e.g. the top is moving forward, thus the conveyor must move back, or the bottom of the wheel is moving back, thus the conveyor is moving forward (although in that case the wheels aren't rotating at all, and so the conveyor belt isn't really moving in the same direction any more).anatech said:
If instead you take it to mean that the conveyor belt as a complete loop is going round in the opposite direction to the wheel then the surface of the conveyor must be moving backwards.
None of those leaps out immediately as being more correct than the others.
I disagree. At best, you can say that as the speed of the conveyor approaches infinity, so does the thrust of the engine, and the state of the system becomes indeterminate and nothing really makes sense anymore.rfbrw said:
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