# Plane on a treadmill **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [September 6, 2008, 8:09pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380 "2008-09-06T20:09:18Z")\ **Posts on this page:** 19\ **Page:** 4
**Author:** ![tullsterx](https://avatars.discourse-cdn.com/v4/letter/t/e9bcb4/32.png) [@tullsterx](https://boards.straightdope.com/u/tullsterx)\ **Post date:** [September 12, 2008, 2:17am UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/61 "2008-09-12T02:17:48Z")
That question is clear and obvious. The speed of the belt is limited to the same speed as the forward motion of the plane. Period. It’s clearly stated in the original question. And is key to the whole premis. Of course, if the speed of the belt is unlimited, then the forward motion of the plance could be arrested, but that’s a whole different question. ---
**Author:** ![warmgun](https://avatars.discourse-cdn.com/v4/letter/w/ecccb3/32.png) [@warmgun](https://boards.straightdope.com/u/warmgun)\ **Post date:** [September 12, 2008, 5:12am UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/62 "2008-09-12T05:12:58Z")
> [@tullsterx](#): > > That question is clear and obvious. **The speed of the belt is limited to the same speed as the forward motion of the plane. Period. It’s clearly stated in the original question.** And is key to the whole premis. > > Of course, if the speed of the belt is unlimited, then the forward motion of the plance could be arrested, but that’s a whole different question. Sorry, **tullsterx** but you are wrong. Period. [Here](http://boards.straightdope.com/sdmb/showthread.php?t=348452&highlight=plane+treadmill) is the original post in full (by the way this appeared in GQ on 12-07-2005, 03:19 PM predating Cecil’s column by two months): > [@bouv](#): > > Will a plane on a treadmill take off? > OK, I have seen this question posted on a couple other message boards I go to, but seeing asd most of the people at those messageboards don’t have a large knowledge of physics, I am posting here in hopes to get the correct answer. > > Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway, and intends to take off. **The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation.** > > Can the plane take off? > > I say no, because the plane will not move relative the the ground and air, and thus, very little airflow will occur over the wings (the engines will create a small amlunt, but not enough.) However, other peopel are convinced that since the wheels of a plane are free spinning, and not powered by the engines, and the engines provide thrust against the air, that somehow that makes a difference and air will flow over the wing. > > So what’s the real answer here\> > [@tullsterx](#): > > There’s a staggering amount of selective reasoning going on in the thread. Funny how that happens, huh? ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [September 12, 2008, 11:13am UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/63 "2008-09-12T11:13:33Z")
> [@tullsterx](#): > > That question is clear and obvious. The speed of the belt is limited to the same speed as the forward motion of the plane. Period. It’s clearly stated in the original question. And is key to the whole premis. Again, > [@zut](#): > > It depends on your **interpretation** of the original question (as well as the **phrasing of the question you’re interpreting** ). Not all **phrasings** of the question are the same. In addition, even given the same phrasing, different people interpret the question in different ways, which by definition means that the exact meaning _is not_ clear and obvious. ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [September 12, 2008, 11:52am UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/64 "2008-09-12T11:52:56Z")
I suppose I should repost this once again: For reference: In case you didn’t know, **Cecil** has two columns on this subject: [An airplane taxies in one direction on a moving conveyor belt going the opposite direction. Can the plane take off? (03-Feb-2006)](http://www.straightdope.com/columns/060203.html) and [“A plane is standing on a runway. . .” No, it’s not. Here’s why. (03-Mar-2006)](http://www.straightdope.com/columns/060303.html) Now, with this particular problem, you have to be aware of a couple things. First is the physics: In order to take off, the plane requires an airflow over the wing, which means the problem reduces to: _Does the plane move with respect to the air around it?_ Next, in order to _prevent_ the plane from taking off, the treadmill has to _stop_ the plane from moving with respect to the air around it. Preventing motion takes force. That means the problem reduces to: _Can and does the treadmill transmit enough force to the plane to prevent it from moving with respect to the air around it?_ Second is the semantics: there are different wordings of the problem and different assumptions that can be made about how it’s set up. Some wordings refer to the speed of the plane, some to the plane’s wheels. Speeds can be measured _relative_ to different objects: relative to the treadmill, relative to the ground, relative to the air. What type of plane are we talking about, and what are the limitations of the system? Different people can and do make different assumptions about what the problem means, and that’s perfectly fine. But–and here’s the real key to the problem–when people argue about what the “answer” to this problem is, it’s _usually not_ because one person is right and one is wrong, it’s because **people start with _different assumptions_ about the question** , and too often don’t bother to state what those assumptions are. So what looks like a physics question becomes a comedy-of-errors semantics question. Now, on to the analysis: * * * There are plenty of answers to this question, because the key to the question is the **wording** and your **interpretation** and **what you assume** from the beginning. And these answers can all be correct, but the **assumptions** are the key. Let’s start off at the top: _ **A.** Suppose we actually built a treadmill and put a 747 on it, and had the treadmill match the speed of the **plane**. Would the 747 take off?_ If the treadmill matches the plane _fuselage speed with respect to the ground_, then yes. The treadmill simply accelerates in the opposite direction that the plane does; the plane moves in one direction relative to the ground and the treadmill moves in the other. The wheels wind up _rotating_ twice as fast as they normally would, but the plane will take off, leaving a treadmill behind that’s rotating in the opposite direction. _ **B.** Let’s reword the question. Suppose we actually built a treadmill and put a 747 on it, and had the treadmill match the **speed of the wheels**. Would the 747 take off?_ Depends. If “exactly matching the speed of the wheels” means that the treadmill matches the _hub speed_ of the wheels (the speed of the wheel center, which is the same as the fuselage speed), then yes. Just like in the last scenario, the treadmill accelerates in the opposite direction that the plane does, the wheels rotate twice as fast as they normally would, and the plane takes off. _ **C.** But that problem is trivial. Let’s assume that “exactly matching the speed of the wheels” means “matching the outer diameter surface velocity”–the velocity with respect to the hub, or the “speedometer” speed. Would the 747 take off?_ Almost certainly it would, but only because we can’t build a treadmill capable of keeping up with the thrust transmitted to the plane by the engines, and _not enough_ force is transmitted to the plane to keep the speeds matched–in other words, we violate the spirit of the question, because the treadmill isn’t matching the wheel velocity. _ **D.** OK, that’s stupid. It’s a thought experiment. Posit a magic treadmill that can accelerate as fast as desired. And it doesn’t break._ I imagine the wheels will skid on the treadmill, because the friction won’t be able to transmit the necessary force. In that case, we again violate the spirit of the question, and– _ **E.** It’s a thought experiment, smart guy. Assume there’s enough friction to rotate the tires._ All right. When the engine lights off, the treadmill will accelerate until the force transmitted through the wheel hub to the plane exactly balances the thrust. The plane would stay stationary as the thrust power was dissipated in the wheel bearings (as friction), tires (hysteresis), and in accelerating the wheel to ever-increasing speeds. Since all the power is dissipated in the wheels, eventually either the bearings would overheat, the tires would blow, or the wheel would rip itself apart due to inertial forces. After that, the plane crashes and burns. Then you’ve destroyed a rather expensive magic treadmill. _ **F.** Thought experiment, I said! Let’s posit ultra-strong and heat resistant tires._ All right. It turns out the real world is rather complicated. If the treadmill is a long, runway-sized treadmill, it will eventually, running thousands of miles an hour, pull in air at high enough velocity that the plane will lift off at zero ground speed (but substantial air speed). However, now you’re running into trans-sonic compressibility effects… _ **G.** No speed of sound effects! And assume magic air that doesn’t become entrained with the treadmill motion. And don’t throw in any other crazy stuff, either._ In that case, the treadmill speeds up (still balancing the plane’s thrust force) and the plane stays in place until the engines run out of fuel. I imagine the treadmill goes pretty fast at that point. The plane stays put until the fuel’s gone, at which point the magic treadmill whips it backwards. _ **H.** Backwards, shmackwards. Now we’re getting somewhere. What if we had infinite fuel?_ Then the wheels keep going until they’re running near light speed, and relativistic effects take over. The wheels get smaller, I suppose… _ **I.** None of that! No relativity-- Hey, wait a minute. Back up. Suppose we have zero friction bearings and tires. That doesn’t seem so unreasonable for a thought experiment._ Well, zero friction tires would mean they just skid on the runway, since nothing turns them. So the plane will take off, tires motionless, and the treadmill won’t move. _ **J.** Hey! Quit it! I already said the tires don’t skid!_ Sorry. Just friction on the tire/treadmill interface, then, but none in the bearing or sidewall. With zero friction in the bearing, you lose the **friction** coupling between the treadmill and the jet. But you still have **inertial** coupling. The wheels _accelerate_, and that acceleration takes force. Now you have the same case as you do _with_ friction. The jet stays stationary as the wheel accelerates; the wheel just accelerates faster. _ **K.** Well, how about the other way around? Massless wheels, but you still have friction?_ Here it starts to get complex: friction is a funny thing and hard to extrapolate. As you accelerate the wheels, the bearings will change shape and heat up and so forth, so the “friction coefficient” goes _up_ with increasing speed, meaning it takes more and more force to keep the wheels rotating. In that the case, then when the engines start, the treadmill accelerates up to whatever speed will give _enough_ friction to balance the thrust. The plane stays stationary, wheels rotating at some reasonably constant (but large) velocity, dissapating the engine power through friction. _ **L.** But I want massless wheels and a constant coefficient of friction. Indestructable wheels, remember? None of this hand-waving “it’s gonna get bigger” crap._ OK. It _is_ a thought experiment, and determining the friction coefficient requires a pretty substantial extrapolation of “real” bearing behavior. With a limited “friction coefficient,” only a limited amount of energy can be absorbed by the friction. When the engine lights off, the treadmill instantly accelerates to infinite speed. It’s never able to counteract the thrust force, and thus plane takes off, leaving the infinite-speed treadmill behind. _ **M.** Ah. OK, one last step. What if we had no bearing friction and massless tires? What happens then?_ Pretty much the same thing. There’s now _no_ energy losses in the wheels and tires, _no_ coupling between the treadmill and the plane–no bearing friction, no inertial effects, no air resistance, and no way for the treadmill to affect the plane’s motion. The same thing would happen as above, with the plane taking off, leaving the infinite-speed treadmill behind. However, there’s one added interesting thing: This is now an unstable runaway system. There’s no resistance to treadmill motion, and a positive feedback circuit. Imagine the poor mechanic who bumps a wheel, setting it in motion. A very slight roll by the tire is sensed, and the treadmill luches forward. The tire goes faster, the treadmill goes faster, the tire goes faster… Since we’ve posited an instantly-accelerating treadmill and no relativity and no air resistance and no wheel inertia, the treadmill goes from zero to infinity in no time flat. Try to keep your balance on that. Pick your scenario–they’re all correct. ---
**Author:** ![TomValois](https://avatars.discourse-cdn.com/v4/letter/t/6bbea6/32.png) [@TomValois](https://boards.straightdope.com/u/TomValois)\ **Post date:** [September 12, 2008, 11:55pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/65 "2008-09-12T23:55:31Z")
> [@Zhing](#): > > [“A plane is standing on a runway. …” No, it’s not. Here’s why. - The Straight Dope](http://www.straightdope.com/columns/read/2642/a-plane-is-standing-on-a-runway-no-its-not-heres-why) > I’ve read both sides of the argument on various forums, and one argument I’ve never seen made against those that say the wheels will spin but the plane won’t take off is this: > > The question states that the treadmill will move in the opposite direction as the plane, not its wheels. If the plane is still, the treadmill won’t move at all. The issue for me is that the question is horribly worded. It tells you that a plane is “moving”, that a sensor is in place to “track its motion”, and then it tries to lay out a scenario under which the plane is actually not moving at all. A plane “takes off” when it reaches a speed, _relative to the air surrounding it_, at which enough lift is generated to overcome the downward force of the mass of the plane. If the plane is not moving relative to the surronding air, it cannot take off, period. So a plane merely spinning its wheels on a treadmill will not take off. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [September 13, 2008, 12:43am UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/66 "2008-09-13T00:43:18Z")
> [@TomValois](#): > > If the plane is not moving relative to the surronding air, it cannot take off, period. So a plane merely spinning its wheels on a treadmill will not take off. True. But (assuming a normal and sensible reading of the problem) that’s not what happens. In spite of the treadmill’s motions, the plane’s engine is able to move it relative to the air, and so it takes off. ---
**Author:** ![TomValois](https://avatars.discourse-cdn.com/v4/letter/t/6bbea6/32.png) [@TomValois](https://boards.straightdope.com/u/TomValois)\ **Post date:** [September 13, 2008, 12:59am UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/67 "2008-09-13T00:59:35Z")
> [@Xema](#): > > True. But (assuming a normal and sensible reading of the problem) that’s not what happens. In spite of the treadmill’s motions, the plane’s engine is able to move it relative to the air, and so it takes off. Well, yes, off course the plane will take off, because it will advance on the treadmill/runway. But I think the intent of the original question was that the treadmill would be adjusted to KEEP the plane from advancing on the runway. So my problem is with the wording of the question itself. I think the person who asked the question intended to ask: “If a plane is motionless on a runway, can it take off?”, and that treadmill was just an example of a device that was supposed to be restraining the plane’s motion. If the intent of the treadmill in the original question was not to restrain the motion of the plane, then I am not sure what the question was supposed to mean at all. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [September 13, 2008, 1:57am UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/68 "2008-09-13T01:57:57Z")
> [@TomValois](#): > > But I think the intent of the original question was that the treadmill would be adjusted to KEEP the plane from advancing on the runway. Right. Some folks’ reaction to this is “Well, the treadmill keeps the plane still with respect to the earth, so there’s no airflow over the wings, so obviously it can’t take off.” Others look a bit more closely and realize that (absent massive and continuous acceleration) the treadmill _can’t keep the plane from moving_ - because there’s no way to exert a retarding force equal to the thrust of the engine(s). So the plane accelerates with respect to the earth, air flows over the wings, and it takes off. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [September 13, 2008, 4:42am UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/69 "2008-09-13T04:42:40Z")
> [@TomValois](#): > > I think the person who asked the question intended to ask: “If a plane is motionless on a runway, can it take off?”, and that treadmill was just an example of a device that was supposed to be restraining the plane’s motion. I don’t think this is a common interpretation. If the intent was to restrain motion, why not specify a long rope tied to the tail, or large chocks in front of the wheels? > [@](#): > > If the intent of the treadmill in the original question was not to restrain the motion of the plane, then I am not sure what the question was supposed to mean at all. The treadmill is a tease - it seems fully plausible (indeed, to many obvious) that it should be able to prevent takeoff, but it can’t. I think the question was designed simply to lead toward the realization that a plane is fundamentally different from a car in that it is not propelled by its wheels (and to trap those who can’t think clearly about the implications of this). ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [September 13, 2008, 5:04pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/70 "2008-09-13T17:04:41Z")
> [@Xema](#): > > The treadmill is a tease - it seems fully plausible (indeed, to many obvious) that it should be able to prevent takeoff, but it can’t. Yep. I fell for it too, until A) the fallacies were pointed out; and B) I actually thought about it a bit more. It’s called a ‘thought question’, but for me it comes down to this: Do you want a factual answer? If you want a factual answer then yes, the airplane takes off. If you want a ‘thought answer’, then the question becomes: If you can build a device that will prevent an airplane from taking off, will the airplane take off? At which point the question is meaningless. ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [September 13, 2008, 7:54pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/71 "2008-09-13T19:54:13Z")
Which to me is what **zut** ’s much-reproduced series of caveats and reconceptions captures brilliantly. If you put a plane on a conveyor belt, it will take off, under any reasonable version of the scenario. But then it turns into a litany of increasingly silly yeah-what-if modifications that reveal that many people for whatever reason _want_ a scenario in which the belt somehow magically holds the aircraft in place, even though they don’t really understand the high-energy physics that might conceivably result in such an effect. Some pursue this because they enjoy the thought experiment; more, I think, persist because then they will have validation that their initial intuitive leap was not in fact incorrect. ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [September 13, 2008, 8:11pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/72 "2008-09-13T20:11:50Z")
Well, to be fair, _if_ you interpret the question as requiring the treadmill match the wheel speed, that implies the plane has zero velocity with respect to the ground. In that case, the required construction of the treadmill is inherent in the question (or, rather, the interpretation of the question), and the “magicalness” is presented as given. And I’ll point out that people ask all sorts of questions like, “if a spaceship goes 99.9% of the speed of light, what happens when you turn on the headlights?” In those cases, no one ever says, “well, you can never build a spaceship that will carry that much fuel, so the question is meaningless.” ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [September 13, 2008, 8:18pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/73 "2008-09-13T20:18:41Z")
I’ll grant that to some extent, but I can’t really go along with it, because that interpretation is inherently meaningless. “The treadmill holds the airplane in place. Does a motionless aircraft take off?” Well, no, obviously, but then that’s not an interesting question. “I’ve made a brick wall you can’t punch through. Can you punch through it?” “I’ve made a chair you can’t sit in. Can you sit in it?” Which is why I keep saying “any reasonable version of the scenario.” If one is going to interpret the scenario to assume the conclusion, then there’s no point in discussing it or even thinking about it. ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [September 13, 2008, 8:34pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/74 "2008-09-13T20:34:08Z")
Likewise, if you interpret the question as matching treadmill speed to fuselage speed with respect to the ground, the problem reduces to, “The plane rolls forward on a treadmill until it takes off. Will the plane take off?” In either case, the question is only meaningless _if_ you already understand the physics behind it. However, not everyone realizes that a) air speed is required for liftoff (in the one interpretation), or b) planes do not depend on powered wheels to roll forward (in the other). ---
**Author:** ![TomValois](https://avatars.discourse-cdn.com/v4/letter/t/6bbea6/32.png) [@TomValois](https://boards.straightdope.com/u/TomValois)\ **Post date:** [September 13, 2008, 10:35pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/75 "2008-09-13T22:35:21Z")
> [@Johnny\_L.A](#): > > Yep. I fell for it too, until A) the fallacies were pointed out; and B) I actually thought about it a bit more. > > It’s called a ‘thought question’, but for me it comes down to this: Do you want a factual answer? If you want a factual answer then yes, the airplane takes off. If you want a ‘thought answer’, then the question becomes: If you can build a device that will prevent an airplane from taking off, will the airplane take off? At which point the question is meaningless. Has anyone considered the possibility that the person who originally submitted the question did not understand how planes fly? Perhaps the person believed that lift came from the power of the engine or turbine - not from the speed of the air over the wings. If you don’t understand the mechanics of flight, you might imagine a plane at full throttle being able to take off vertically even if its horizontal motion is somehow restrained. In all honesty, that is how I read the question. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [September 16, 2008, 2:21pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/76 "2008-09-16T14:21:00Z")
**TomValois** said: > [@](#): > > I think the person who asked the question intended to ask: “If a plane is motionless on a runway, can it take off?”, and that treadmill was just an example of a device that was supposed to be restraining the plane’s motion. The intent of the question is sufficiently vague, but you may be right. **bouv** does appear to assume that the treadmill holds the plane still with respect to the ground, and feels if that happens there is not enough air to get liftoff. My response is a sufficient headwind could allow takeoff, but that might be a bit much (hurricane force). Now if you put the treadmill on top of an aircraft carrier and drive into the wind… 😉 From the original question: > [@](#): > > However, other people are convinced that since the wheels of a plane are free spinning, and not powered by the engines, and the engines provide thrust against the air, that somehow that makes a difference and air will flow over the wing. This _strongly_ suggests that the original non-SD debaters are not communicating the assumptions and intents very well. **bouv** is addressing what happens if the fuselage is held constant with respect to the ground (by whatever method, which could include ropes if that matters as long as they don’t prevent vertical motion) and is confused how having free-spinning wheels will allow air flow over the wing of the plane while the fuselage is still with respect to the ground. His opponents seem to be addressing how a plane moves on the ground and how a treadmill will affect it, rather than what happens if a plane does not move with respect to the ground. ---
**Author:** ![koalaroo](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@koalaroo](https://boards.straightdope.com/u/koalaroo)\ **Post date:** [September 25, 2008, 7:01pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/77 "2008-09-25T19:01:32Z")
Lots of interesting discussion here, but the answer is clearly that the plane will take off. The reason why is that the forces that allow a plane to fly have nothing to do with the wheels…if the wheels mattered, a plane wouldn’t be able to continue flying once the wheels are off the ground. Think of it this way: how is it that a plane moves forward through the air when it is not on the ground? The propeller or jet engine pushes against the air and Newton’s 3rd law (equal and opposite reaction) means the air, via the engine, pushes back against the plane moving it forward. The only point of the wheels (or pontoons for a sea plane) is to keep the plane horizontal and supported while it develops enough speed relative to the air in order to generate lift. The propeller will pull the plane through the air in order to develop the speed…this is not dependent upon traction from the wheels. In fact, friction actually means the wheels slightly oppose the build up of speed through the air. If a plane somehow relied on traction of its support structure to the ground, sea planes wouldn’t be able to take off, and they clearly can. ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [September 25, 2008, 8:08pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/78 "2008-09-25T20:08:15Z")
> [@koalaroo](#): > > Lots of interesting discussion here, but the answer is clearly that the plane will take off. The reason why is that the forces that allow a plane to fly have nothing to do with the wheels…if the wheels mattered, a plane wouldn’t be able to continue flying once the wheels are off the ground. a) I’m reasonably sure everyone (at least, most people in this thread) knows that the forces that allow a plane to fly have nothing to do with the wheels. b) Whether or not that’s significant to the problem, and whether or not it leads to the conclusion you state, depends on your assumptions about the problem. c) There has been much discussion of all these points, both in this thread and preceding ones. ---
**Author:** ![Bad\_Astronaut](https://avatars.discourse-cdn.com/v4/letter/b/e19adc/32.png) [@Bad\_Astronaut](https://boards.straightdope.com/u/Bad_Astronaut)\ **Post date:** [September 25, 2008, 8:23pm UTC](https://boards.straightdope.com/t/plane-on-a-treadmill/462380/79 "2008-09-25T20:23:56Z")
I wonder if the original poster might have been thinking about a prop plane, and imagining that the propeller might be able to create enough air movement over a stationary plane to generate lift? P.S. koalaroo - welcome to [BR #1](http://www.straightdope.com/columns/read/2642/a-plane-is-standing-on-a-runway-no-its-not-heres-why). [Previous page](https://boards.straightdope.com/t/plane-on-a-treadmill/462380.md?page=3)