So the age long question since we have all this controversy lately.. I think this was up on this site a while back, searched and couldn't find it.
The question is (if you don't know it already), if an airplane tried to take off on a conveyor belt going the same speed in the opposite direction, would it be able to take off? Say the take-off speed is 100mph, the conveyor belt goes 100mph in the opposite direction, will it be able to take-off. I'll hold my answer and argument until we get some responses. This should be good, and don't bring mythbusters crap in here, I want your ideas.
No.
unless its "AIR SPEED" is 100....
the air under the air foils.
Chris
"An appeal to arms and the God of hosts is all that is left us. But we shall not fight our battle alone. There is a just God that presides over the destinies of nations. The battle sir, is not of the strong alone. Is life so dear or peace so sweet as to be purchased at the price of chains and slavery? Forbid it almighty God. I know not what course others may take, but as for me, give me liberty, or give me death."
Speech at the Second Virginia Convention at St. John's Church in Richmond, Virginia (23 March 1775) Patrick Henry
Well, say the pilot increases thrust normally. I guess that's what the situation is, this is a "normal" take-off.
I've never understood why there was so much discussion about this, planes aren't driven by the wheels, so what is under it has very little effect. Sure it will slow the plane a bit due to friction, but all you have to do is increase the prop speed or the turbines and you make up for the friction with very little effort.
I still can't believe Mythbusters devoted an entire episode to something so obvious...
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
A conveyor belt would be pointless. All you need is a fan that produces 100mph winds, duh...
Actually if the head wind is as fast as the take of speed of the plane it could leave the ground it just wouldnt really be moving (think of how you see a bird flying into the wind but not actually going anywhere).
For some reason I want to put a parrot on a treadmill now LOL
post from the other thread
Quote:
Sure with the engine running at idle (prop plane) if the plane where sitting on a running treadmill big enough to actually hold the thing, the friction caused by the bearings in the wheels would cause the plane to move backwards, but as soon as the engine was throttled it would move forwards just fine, and since we arnt dealing with staic friction anymore (the wheels are turning) the the effect of the treadmill would be negligible.
Now if you added one hell of a head wind that might cause a problem, but technically, the plane could still lift off the ground but just not move forward in a 80mph headwind.
A plane gets its forward momentum from the propeller slicing through the air wich is not related to the ground at all. And the thrust created is much more then needed to over power the kinetic friction in the wheel bearings. The plane would take off, the tires would just be spinning faster then if the plane was on stationary ground.
Basically, the thrust is created my acting against the atmosphere not the surface of the earth, and the drag caused by the surface moving backwards under it is no where near enough to counteract the thrust acting against the atmosphere.
I can go into greater detail if you want.
think about this: can you LAND a plane on a treadmill?
how do you think you can take off from one?
so if I wore skates and a jet pack on a conveyor belt...
would I look cool?
J03Y wrote:holy 3 years ago batman
haha..I know I remembered that thread and all of the idiots. I just wanted to stir the pot and see how many more we could bring out, but apparently people have gotten smarter since then.
KevinP (Stabby McShankyou) wrote:think about this: can you LAND a plane on a treadmill?
how do you think you can take off from one?
OF course you could land a plane on a treadmill LOL although it would probably break the treadmill (im not talking about the one you run on of course, im talking about a specially made one big enough to hold a plane)
The only way it wouldnt be able to take off is if you forgot to release the parking brakes.
I dont understand how some people just dont get this... how do you think a plane keeps moving when its off the ground? Even when a plane lands the wheels are just there so the plane can roll around on the ground (and for steering on the ground) they have nothing to do with how its powered... the prop it what moves the plane forward when its taxi'ing on the runway not the wheels...
Its actually pretty simple if you have any idea how a plane works, although I've flown a plane before and even studied pilots manuals as a kid so I might know more about it then the average person.... being a pilot is one of the things I;ve always wanted to do bad sadly never will have the money.
I'm a pilot, and have an aviation degree, so I know the ins and outs pretty well
Weebel...is there anything you haven't done?
Quote:
unless its "AIR SPEED" is 100....
So I was wrong?
Chris
"An appeal to arms and the God of hosts is all that is left us. But we shall not fight our battle alone. There is a just God that presides over the destinies of nations. The battle sir, is not of the strong alone. Is life so dear or peace so sweet as to be purchased at the price of chains and slavery? Forbid it almighty God. I know not what course others may take, but as for me, give me liberty, or give me death."
Speech at the Second Virginia Convention at St. John's Church in Richmond, Virginia (23 March 1775) Patrick Henry
So I was correct in saying it would not fly unless the air speed was 100.....
I never said sh!t about the wheels...
Chris
"An appeal to arms and the God of hosts is all that is left us. But we shall not fight our battle alone. There is a just God that presides over the destinies of nations. The battle sir, is not of the strong alone. Is life so dear or peace so sweet as to be purchased at the price of chains and slavery? Forbid it almighty God. I know not what course others may take, but as for me, give me liberty, or give me death."
Speech at the Second Virginia Convention at St. John's Church in Richmond, Virginia (23 March 1775) Patrick Henry
does a fan suddenly take off when you turn it on?
KevinP (Stabby McShankyou) wrote:does a fan suddenly take off when you turn it on?
No, it blows me.
your question really doesn't help or hurt your argument as a fan isn't designed to be propelled by it's operation (although it does exert a force opposite the direction of airflow)
I did change the pulleys out on an industrial fan at work so it would turn at the same speed of the motor (1200 rpm). We ended up bolting it to the floor because it would tip itself over whenever it was started even though the existing metal base was around 30 pounds.
LOL I havnt done everything, but I have done a lot of crap.. Theres a reason I've started to settle down a little already by my late 20's.
Like I said, flying has been an obsession for me since I was a little kid, im a little fuzzy on navigation things now (VOR and how ILS works and crap) but I know a lot about planes and flying in general just because I've always been so intersted in them. When I was 12 or so I got to ride in a cherokee once, and the pilot let me take over the controls (he wasnt touching them) and he about crapped when I adjusted the trim, was flying withought being told how and was even able to line the plane up for final approach (he was telling me when to turn because I couldnt see over the dash at all), he didnt touch the controls again until we where lowering flaps but then I was still flying, He did take over to set it on the ground though.... He didnt believe my dad when he told him I've never flown before LOL,
Not to tell a story, its just adds some background on where I stand on the subject.
KevinP (Stabby McShankyou) wrote:does a fan suddenly take off when you turn it on?
If someone wired your garage with 220 for the 110 outlets.... yes, yes it will....
and burns out your drill really fast.... and the radio's....
Chris
"An appeal to arms and the God of hosts is all that is left us. But we shall not fight our battle alone. There is a just God that presides over the destinies of nations. The battle sir, is not of the strong alone. Is life so dear or peace so sweet as to be purchased at the price of chains and slavery? Forbid it almighty God. I know not what course others may take, but as for me, give me liberty, or give me death."
Speech at the Second Virginia Convention at St. John's Church in Richmond, Virginia (23 March 1775) Patrick Henry
^^^^ hire a crappy electrician? LOL
im going to go ahead and say no, after about 2hours of scratching my head with a yea if this and that, and then some no no gotta have that. i would be a great idea if you could get a fan to provide enough "lift" for the jet to take off.
then you run into the problem if the plane has lift, the throttle is at full thrust lifts up from the conveyor belt and away from the fan will the jet be able to carry that pocket of air with it long enough that the engines can force more air under the wings to provide more lift.
for thoes of you who think its possible, when you run on a treadmill, do you feel wind hitting your face even though your running? no you do not and because jets require air flow to provide a pocket of air under the wings which provide lift to get off the ground. it is not possible
No one is saying it's possible for the plane to take off if it is still stationary and has insufficient head wind. That's what makes this question so unbelievability stupid.
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
well the airplane on the conveyor is more than just a yes or no question.
a fan doesn't fly off when you start it because of gravity, friction, and the thrust required to move it.
it's impossible to LAND a plane on a treadmill because you would have to suddenly stop all of it's forward momentum and let gravity take over.
a plane flies because lift helps it defy gravity--in which case it needs to move forward--in which case the force of gravity pulling the plane down onto the wheels does in-fact dictate that wheels are part of the equation.
it's simple: if a plane produces enough thrust to move forward; it doesn't neccesarily produce enough thrust to overcome gravity instantly like some people are thinking.
that being said; the plane CANNOT leave the treadmill if thrust + lift are < gravity + friction; further still, if thrust and lift are greater than the opposing forces, they still may not produce enough forward motion in order for the plane to successfully "fly." it may bounce; but flight is probably not likely in this case.
