# Flight and the Conveyor Belt **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [February 3, 2006, 12:25am UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759 "2006-02-03T00:25:10Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [February 3, 2006, 4:03pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/21 "2006-02-03T16:03:16Z")
Hi there to all our guests. Welcome to the SDMB! One of our little assumptions here is that when people come here to discuss one of Cecil’s columns, they’ll provide cites and quotes from it to base their discussion on. In most cases, we’ve found that bringing in outside elements tends to confuse the issue, as Cecil’s main gig is to focus an issue down to its relevant points. So, for all those of you posting that it’s all about the lift, or the wings, or the airflow over the wings: Can you take another look at what Cecil was talking about, set aside all the discussion you’ve gone through on other boards, and respond to what Cecil said? His points: 1. The wheels do not make the plane move. They just spin. 2. The conveyor belt cannot provide a significant amount of force to the plane itself, as the wheels are free to rotate. 3. The engines exert a _lot_ of force on the body of the plane and push it forward. 4. There is _no force whatsoever_, aside from the minimal friction in the wheels, pushing backward on the plane. Since there are big, honkin’ jet engines pushing the plane forward, and very little pushing it backward, where are you getting all the force necessary to keep the plane from moving forward? ---
**Author:** ![JustAnotherGeek](https://avatars.discourse-cdn.com/v4/letter/j/58f4c7/32.png) [@JustAnotherGeek](https://boards.straightdope.com/u/JustAnotherGeek)\ **Post date:** [February 3, 2006, 4:03pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/22 "2006-02-03T16:03:52Z")
I almost posted a scathing and totally wrong critique of **The Perfect Master’s** column. Then I started to think about the problem a bit more… He is, of course, right. However, uncharacteristically, he did not explain the ideas involved as clearly as possible. If we assume frictionless spinning of the wheels, the speed of the ground does not signify. Even if we assume that there is some friction in the spinning of the wheels, the speed of the ground does not signfy once the forward force of the engine overcomes the small backwards force that the treadmill exherts on the plane. Ask yourself this: assume that the airplane is sitting on a totally frictionless landing gear system. Think silicon-coated skids on the clearest, smoothest ice you can imagine. Now, the plane fires up its engines. What happens? The plane, of course, takes off as normal. Now, put the plane back on wheels, but on solid ground, and the plane fires up its engines. What happens? The plane moves forwards and the wheels spin according to (omega) = v(plane) / r(wheel). Where (omega) is the angular speed of the wheels, and the v(plane) is the speed of the plane relative to the ground. Now, let’s try the treadmill. The only thing that happens is that the v(plane) doubles, and hence the (omega) doubles. The engines still push or pull the plane through the air. The wheels spin twice as fast. > [@The Perfect Master](#): > > As you point out, one problem here is the wording of the question. Your version straightforwardly states that the conveyor moves backward at the same rate that the plane moves forward. If the plane’s forward speed is 100 miles per hour, the conveyor rolls 100 MPH backward, and the wheels rotate at 200 MPH. 200 MPH isn’t the right way to say this; the wheels still move forward (compared to the outside observer) at 100 mph, they spin at 2x(omega) = 100mph / r(wheel). Remember: there are _two_ kinds of velocity: translational and rotational. The wheels get their _translational_ motion from the plane’s engines pushing/pulling the body forward. The wheels would have this motion on a frictionless surface (where they would not roll at all). The wheels get their _rotational_ velocity from the interaction of the surface and the forward motion of the plane. In short, **Cecil’s** right. But, deep down, you knew that anyway. ---
**Author:** ![wayward](https://avatars.discourse-cdn.com/v4/letter/w/a87d85/32.png) [@wayward](https://boards.straightdope.com/u/wayward)\ **Post date:** [February 3, 2006, 4:05pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/23 "2006-02-03T16:05:02Z")
> [@mswart99](#): > > … > This is exactly the situation for the airplane. Oh no it’s not. The glider (via the car) is pushing against the ground to move itself forwards. The ground, relative to a stationary observer, is moving so the glider doesn’t take off. The plane is pushing against the air to move itself forwards. The air, relative to a stationary observer (and assuming no wind) is not moving, so the plane does take off. The action of the conveyer belt doesn’t matter. The thrust of the engines is equivalent to a rope pulling the plane forwards. The conveyer belt is not equivalent to a rope holding it back. I don’t to join in the inevitable debate about this, so i’ll just sit back and feel smug because I agree with Cecil. ---
**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:** [February 3, 2006, 4:05pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/24 "2006-02-03T16:05:22Z")
> [@mswart99](#): > > NO! Because there is never any net airflow over the wings. This is exactly the situation for the airplane. > [@Engywook](#): > > FTR, my $0.02 is with the no-airspeed, no-lift camp. In my caffeine-deprived state, someone beat me to the question. > [@Engywook](#): > > Nobody out there at all with a treadmill and a radio control model plane? Seems there must be a way to settle this empirically… Looks like a job for _Mythbusters_. ---
**Author:** ![Stentor\_2.5](https://avatars.discourse-cdn.com/v4/letter/s/bc8723/32.png) [@Stentor\_2.5](https://boards.straightdope.com/u/Stentor_2.5)\ **Post date:** [February 3, 2006, 4:06pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/25 "2006-02-03T16:06:43Z")
To me the matter at stake is friction reduction. To get enough air flowing over the wing a plane still needs to achieve a certain speed on the ground, and to achive this speed it needs to overcome the friction the ground exerts on it. A plane with its wheels bolted in a static postition relative to the strut probably won’t take off, unless it has an engine that is unrealistically strong enough to literally drag the landing gear across the runway at an appropriate speed (and not destroy the plane in the process). Taking the bolts off the wheels will reduce the landing gear’s friction by several orders of magnitude, but won’t get rid of it entirely. The tires will still exert some micro friction. So I think the necessary equation would be (I have very little physics training, so my terms might not be orthodox) C\*f\> t in order to prevent take off where C is the speed of the conveyer belt, f is a coefficient describing the friction reduction effect of the wheels in their current state (bolted is a number approaching infinity, free spinning is a number close to, but not quite, zero) and t is the force applied by the engine at full power. Like Cecil I agree that the “conveyer belt reacting to the speed of the tires” theory creates a paradox and should be ignore. So my answer is that it is possible that being situated on a conveyer belt could prevent a plane from taking off, but it would have to be one hell of a conveyer belt. This also explains why the seaplane will have a harder time taking off, since a seaplane’s landing gear is not nearly as efficient a friction reducer as a properly greased ball bearing. ---
**Author:** ![smellsofbikes](https://avatars.discourse-cdn.com/v4/letter/s/7bcc69/32.png) [@smellsofbikes](https://boards.straightdope.com/u/smellsofbikes)\ **Post date:** [February 3, 2006, 4:07pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/26 "2006-02-03T16:07:24Z")
> [@stevekelner](#): > > Keithwins has answered to his satisfaction that a plane which pushes air across the wing (e.g., old front-mounted props) might lift even if not allowed to move forward, but a modern jet would not, because it relies more on that pushing forward. I’m not convinced. I think even a prop plane might get a little light on its wheels, so to speak, but I doubt it would go up. It is a plane, not a rocket. They do. When you’re practicing _very_ short take-off and landing in a Piper Supercub, a tailwheel aircraft (as in two big wheels up front, one small one in the back) you stomp on the brakes, and bring the engine up to near-full-power, and the air from the prop is sufficient to lift the tail so you’re balanced on two wheels. But you’re nowhere near flying. In marked contrast, when the winds are very strong you better hope your Supercub is tied down because, with the engine off and the wheels not rotating and no conveyor anywhere in sight, as soon as the wind speed is higher than the airplane’s stall speed, it’ll fly. Briefly. As other people have said, all that matters is airspeed over the wings, and the angle at which the wing is hitting the air. If you’re in a steep dive and try and pull out, you can stall the wings at high speed because the airflow no longer sticks to the wings, and suddenly you have no lift. Again, no engine, conveyor, or wheels needed. But you can tow a glider into the air without an engine by making it go through the air quickly, and you can fly a plane backwards _with respect to the ground_ if you’re flying into a headwind that exceeds your groundspeed. In the plane, you don’t notice any change: it’s still flying just fine, but you’re going backwards over the ground. Same thing with the conveyor. Turn the conveyor on, turn it off, run the engine, don’t run the engine. Doesn’t matter. If the airspeed over the wing exceeds the aircraft’s stall speed, the aircraft will fly. ---
**Author:** ![JustAnotherGeek](https://avatars.discourse-cdn.com/v4/letter/j/58f4c7/32.png) [@JustAnotherGeek](https://boards.straightdope.com/u/JustAnotherGeek)\ **Post date:** [February 3, 2006, 4:07pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/27 "2006-02-03T16:07:47Z")
> [@mswart99](#): > > Engines do not make airplanes fly, whether they are propellers, or jets. > > It’s the wings. It’s ALWAYS the wings. The engines are there to push the airplane fast enough to push sufficient air over the wings to generate lift. > > \ > > So let’s restate the problem: > > A glider is being towed behind a car, which is on a big conveyor belt. The conveyor belt turns to counteract the forward speed of the car, such the car never moves forward or backwards along the runway. Does the glider take off? > > \ No, but that’s not the same problem. The car gets its forward motion by pushing off of the ground. A plane gets its forward motion by pushing through the air. Ask yourself: if the wheels are so important, how to ski-planes take off? ---
**Author:** ![smellsofbikes](https://avatars.discourse-cdn.com/v4/letter/s/7bcc69/32.png) [@smellsofbikes](https://boards.straightdope.com/u/smellsofbikes)\ **Post date:** [February 3, 2006, 4:16pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/28 "2006-02-03T16:16:24Z")
> [@Stentor 2.5](#): > > To me the matter at stake is friction reduction. To get enough air flowing over the wing a plane still needs to achieve a certain speed on the ground, and to achive this speed it needs to overcome the friction the ground exerts on it. A plane with its wheels bolted in a static postition relative to the strut probably won’t take off, unless it has an engine that is unrealistically strong enough to literally drag the landing gear across the runway at an appropriate speed (and not destroy the plane in the process). I’ve taken off this way twice. Both times we landed on slush and deep snow, stopped, set the parking brake, came back to the plane, and forgot to release the parking brake. The plane accellerated through the snow somewhat more slowly, but then again it always does. It was when we came in for landing on a dry pavement runway that things got really interesting. (neither time was I the pilot. Yes it was stupid, no it wasn’t precisely my fault.) Someone else has pointed out that the airplane in Cecil’s question isn’t actually fixed, so the conveyor belt is doing nothing but screwing around with the wheels. This is basically the same situation, now that I think about it, so I’m going to go with Cecil here, now that I consider it. There’s no difference between the conveyor belt and a frictionless surface. The airplane’s engine will push air backwards, accellerating the airplane forwards, until such time as the airflow over the wings exceeds the stall speed, when the airplane will take off. All the fancy business with the conveyor is totally extraneous. It’s just an airplane on rather odd ice. I’d hate to try _landing_ on the conveyor belt. ---
**Author:** ![SPStover](https://avatars.discourse-cdn.com/v4/letter/s/4491bb/32.png) [@SPStover](https://boards.straightdope.com/u/SPStover)\ **Post date:** [February 3, 2006, 4:17pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/29 "2006-02-03T16:17:39Z")
I think the easiest way to understand why the plane, jet or what ever would not take off is to drive down the highway at 60mph and stick your little five-fingered airfoil out the window and experience the lift on your hand. Now put your car on a conveyor belt, drive at 60mph and stick your hand out again noticing the absence of lift. Lift on the wings is what causes a plane to fly unless it is a VTAL such as a helicoptor where the “wing” moves through the air or a jet that forces thrust in the form of jet exhaust downward sufficient to overcome gravity. ---
**Author:** ![JustAnotherGeek](https://avatars.discourse-cdn.com/v4/letter/j/58f4c7/32.png) [@JustAnotherGeek](https://boards.straightdope.com/u/JustAnotherGeek)\ **Post date:** [February 3, 2006, 4:19pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/30 "2006-02-03T16:19:32Z")
**Johnny L.A.** I’m going to quote you, but I am also going to break your quote up into the individual points to discuss this easier. > [@Johnny L.A.](#): > > 1.) A propeller does move air over the airframe. > > 2.) Only (let’s assume a single-engine aircraft) it does not push air over the entire span of the wings. So let’s assume a single-engine jet. A-4 Skyhawk, BD-5J, whatever. Air goes into the intake and comes out the back as thrust, with no flow over the flying surfaces. Let’s further assume that the experiment is taking place outside on an absolutely calm day. > > 3.) So you fire up the turbine. The aircraft tries to move forward through the airmass. > > 4.) But the conveyor belt moves beneath it at the same speed, so the aircraft remains stationary in space. > > 5.) If the aircraft remains stationary in space, and thus the flying surfaces are not moving through the airmass, where does the lift come from? (all the numbering is me) 1.) True, but not important. The propeller pulls the wing/plane through the air. 2.) Mostly true. The jet does not pull the air over the wing, it pushes the wing (with the plane) forward through the air. 3.) Very true, and the WHOLE POINT. 4.) Incorrect. The wheels spin faster, but assuming low friction transmitted to the plane, the plane moves forward at pretty much the same speed. 5.) That’s the point: the airplane _does not_ remain stationary. The forward force comes from the engine, not the wheels pushing on the ground. The wheels, in fact are dragged backwards on the ground in a normal situation. Unless the friction of the bearings in the wheel can overcome the forward force of the engine, the plane still moves forwards, has airflow over the wings, and takes off. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [February 3, 2006, 4:23pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/31 "2006-02-03T16:23:01Z")
> [@SPStover](#): > > I think the easiest way to understand why the plane, jet or what ever would not take off is to drive down the highway at 60mph and stick your little five-fingered airfoil out the window and experience the lift on your hand. Now put your car on a conveyor belt, drive at 60mph and stick your hand out again noticing the absence of lift. Lift on the wings is what causes a plane to fly unless it is a VTAL such as a helicoptor where the “wing” moves through the air or a jet that forces thrust in the form of jet exhaust downward sufficient to overcome gravity. What is keeping the engines on the plane from moving the plane forward? ---
**Author:** ![Stentor\_2.5](https://avatars.discourse-cdn.com/v4/letter/s/bc8723/32.png) [@Stentor\_2.5](https://boards.straightdope.com/u/Stentor_2.5)\ **Post date:** [February 3, 2006, 4:24pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/32 "2006-02-03T16:24:17Z")
> [@smellsofbikes](#): > > I’ve taken off this way twice. Both times we landed on slush and deep snow, stopped, set the parking brake, came back to the plane, and forgot to release the parking brake. The plane accellerated through the snow somewhat more slowly, but then again it always does. It was when we came in for landing on a dry pavement runway that things got really interesting. (neither time was I the pilot. Yes it was stupid, no it wasn’t precisely my fault.) You’ll note that my example said nothing about a parking brake. I said with the wheels bolted in place such that movement relative to the strut is impossible. Not difficult, impossible. Put a parking enforcement style boot on your plane’s wheels. It’s not going anywhere. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [February 3, 2006, 4:27pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/33 "2006-02-03T16:27:27Z")
> [@SPStover](#): > > Lift on the wings is what causes a plane to fly unless it is a VTAL such as a helicoptor where the “wing” moves through the air or a jet that forces thrust in the form of jet exhaust downward sufficient to overcome gravity. You are absolutely, 100% correct. Tell me something. What causes the plane to _ **move?** _ ---
**Author:** ![Stentor\_2.5](https://avatars.discourse-cdn.com/v4/letter/s/bc8723/32.png) [@Stentor\_2.5](https://boards.straightdope.com/u/Stentor_2.5)\ **Post date:** [February 3, 2006, 4:28pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/34 "2006-02-03T16:28:48Z")
If a mod could fix my quotation I would be grateful. ---
**Author:** ![PetW](https://avatars.discourse-cdn.com/v4/letter/p/d2c977/32.png) [@PetW](https://boards.straightdope.com/u/PetW)\ **Post date:** [February 3, 2006, 4:31pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/35 "2006-02-03T16:31:54Z")
> [@SPStover](#): > > I think the easiest way to understand why the plane, jet or what ever would not take off is to drive down the highway at 60mph and stick your little five-fingered airfoil out the window and experience the lift on your hand. Now put your car on a conveyor belt, drive at 60mph and stick your hand out again noticing the absence of lift. Lift on the wings is what causes a plane to fly unless it is a VTAL such as a helicoptor where the “wing” moves through the air or a jet that forces thrust in the form of jet exhaust downward sufficient to overcome gravity. The whole point is that the plane still moves forward on the treadmill, because the slight friction of the wheels moving isn’t enough to slow down the forward momentum of the plane. In your example, the car doesn’t move forward because a car moves forward because of it’s wheels. Jet engines don’t power the wheels. ---
**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:** [February 3, 2006, 4:35pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/36 "2006-02-03T16:35:49Z")
> [@JustAnotherGeek](#): > > 4.) Incorrect. The wheels spin faster, but assuming low friction transmitted to the plane, the plane moves forward at pretty much the same speed. > > 5.) That’s the point: the airplane _does not_ remain stationary. The forward force comes from the engine, not the wheels pushing on the ground. The wheels, in fact are dragged backwards on the ground in a normal situation. > > Unless the friction of the bearings in the wheel can overcome the forward force of the engine, the plane still moves forwards, has airflow over the wings, and takes off. See, this is where I’m confused. The way I’m reading the question is that the conveyor belt moves at such a speed that it will not allow any forward motion of the aircraft. ---
**Author:** ![wayward](https://avatars.discourse-cdn.com/v4/letter/w/a87d85/32.png) [@wayward](https://boards.straightdope.com/u/wayward)\ **Post date:** [February 3, 2006, 4:39pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/37 "2006-02-03T16:39:34Z")
> [@Johnny L.A.](#): > > See, this is where I’m confused. The way I’m reading the question is that the conveyor belt moves at such a speed that it will not allow any forward motion of the aircraft. That’s the way it was originally worded, which is why it’s a silly question. Even if the conveyer belt could keep speeding up to infinity (and beyond!) the plane would still move. ---
**Author:** ![SPStover](https://avatars.discourse-cdn.com/v4/letter/s/4491bb/32.png) [@SPStover](https://boards.straightdope.com/u/SPStover)\ **Post date:** [February 3, 2006, 4:41pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/38 "2006-02-03T16:41:50Z")
> [@gazpacho](#): > > What is keeping the engines on the plane from moving the plane forward? The plane is moving forward relative to the conveyor belt but has no lift to overcome gravity. Whether the forward force comes from wheels pushing against the ground or the prop/jet blades pushing against the air makes no difference. As for the thought that the engines push the air over the wings causing the lift- How do you explain how a jet with the engines mounted on the tail flies(a Boeing 727 for example) ---
**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:** [February 3, 2006, 4:46pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/39 "2006-02-03T16:46:14Z")
> [@Johnny L.A.](#): > > See, this is where I’m confused. The way I’m reading the question is that the conveyor belt moves at such a speed that it will not allow any forward motion of the aircraft. What I mean is this: If we allow that the airplane will be able to move forward on a conveyor belt, then there is no need for the conveyor belt. We could have a stationary runway and the question would be whether an aircraft can take off when it attains the proper airspeed. It would be pointless. Now in a no-wind situation, a fixed-wing aircraft must move along the ground in order to move the wings through the air. If the ground is moving in the opposite direction to the aircraft at the same speed of the aircraft, then the aircraft remains stationary in space and there is no airspeed. A Cessna 172 rotates at about 60 knots. If the conveyor belt is running the other way at 60 knots, then the Cessna’s airspeed is nil (60 - 60 = 0). If the pilot applies enough power to provide 120 kts, and the conveyor belt is running the other way at 60 kts, then the Cessna will move forward at 60 kts (120 - 60 = 60). So it will fly. So since an aircraft that attains the necessary airspeed will fly, then it’s obvious that all it has to do is to match the speed of the conveyor belt and then add the necessary speed to move forward on the conveyor belt until it reaches flying airspeed. So the way I read the question is that the aircraft will not move forward on the conveyor belt because the conveyor belt matches its groundspeed. If the airspeed is zero, then it doesn’t matter what the groundspeed is. ---
**Author:** ![JustAnotherGeek](https://avatars.discourse-cdn.com/v4/letter/j/58f4c7/32.png) [@JustAnotherGeek](https://boards.straightdope.com/u/JustAnotherGeek)\ **Post date:** [February 3, 2006, 4:47pm UTC](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759/40 "2006-02-03T16:47:18Z")
> [@Johnny L.A.](#): > > See, this is where I’m confused. The way I’m reading the question is that the conveyor belt moves at such a speed that it will not allow any forward motion of the aircraft. That’s where everyone, myself included, gets confused. _How_ will the conveyor belt prevent forward motion of the plane? What forces will it exhert on the plane? The only thing the conveyor belt can do is to pull back harder on the wheels, making them spin more. So long as the wheels are free to spin, the ground motion makes no difference to a plane. Ask yourself this: If you go out and buy some _really_ good skateboard wheels, and have someone sit on the skateboard on a (flat) treadmill, how much force will you need to exhert to keep the person stationary on the treadmill? Not much, right? How much force would you need to exhert to push the person forwards (assuming you are not on the treadmill)? Not much more than you would if the skateboard were on the ground. It boils down to the fact that the engines of an airplane have no direct communication with the ground. They don’t push against the ground like the engine of a car does (through its own tires). Assuming the treadmill is not super-hyper-ultra powerful enough to convert the small amount of friction pulling back on the plane into a large enough force to keep the plane still, the plane moves through the air. Please read (if you haven’t already), my first post here (# 22, if I count correctly) to see how little wheels matter to a plane. [Previous page](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759.md?page=1) [Next page](https://boards.straightdope.com/t/flight-and-the-conveyor-belt/342759.md?page=3)