Z-Man

Did not. I told you. The suspended gyroscope still acts like a regular pendulum if you push it. It differs from the regular pendulum by the two additional relevant degrees of freedom driven mainly by precession (there is interaction between them and the regular pendulum degrees of freedom). Those degrees of freedom are already there in the regular pendulum (take one, rotate the weight about the x axis, release), of course, it's just that they are strongly damped and thus not normally relevant. There are practical reasons. On an air table, a light tower would easily get rotated sideways, causing uneven air flow and unwanted thrust. On the flip side, there is no reason to consider the Cambridge experiment irrelevant. If the claim is that a light tower is not moved by a precessing gyro, surely a heavy tower would budge even less.

Nice. Definitely try to run the experiment twice, once at home and once in the hall, the only difference being the line lengths. If you really are producing thrust, the hall experiment should give you a larger linear average displacement.

Nah, just where it is unscientific. That does not mean it is wrong.I thank you, too. I certainly learned a lot.

I'd say. Despite my best efforts, mine thinks the moon is glued to the sky, and she confused Venus for Earth more than once. (I'm to blame for that one. I refuse to tell her outright that Earth is where we live.)

Same as any other mandatory field: School is supposed to give you a broad base education. You'll specialize soon enough.

That could be useful. And make sure the fishing lines are parallel at the start. If they are not, a simple internal shift in weight can produce a permanent tilt and thus movement of your laser dot. And ideally, mount the device so that in operation, its average center of mass is in the center of the fishing lines, and that the downward laser pointer is also right below the average center of mass. That way, expected rotations about the Z axis influence it the least.

You're thinking of a different Alex Jones.

Well, in that case, good luck. Random dump of advice: Do get some background. Any decent classical mechanics book should have a chapter on gyroscopes. Read that. If you don't know how precisely we think they should operate, you can't tell what observed behavior is anomalous. If you can, find out about why it is believed that momentum is conserved. K^2 is correct in that it is a direct consequence of the translation invariance of the laws of physics. However, the proof is not without context. It assumes the Lagrangian framework of theoretical mechanics can be applied. If it can't (*), then translation invariance may hold without conservation of momentum. Every theorem has prerequisites, and those are your potential loopholes. Instead of building a complete propulsion system from nothing, try finding anomalous behavior in the individual isolated components first. The combustion engine was not built prior to understanding combustion, electric motors were only built after people developed a solid understanding for (electro)magnets. I'd start by trying to replicate Eric Laithwaite experiments on the lack of centrifugal force. The basic one (as seen on the TV lecture) has been falsified, but in his patent application, he writes about gyros with fat rims giving better results. I haven't seen those repeated yet, though I have to admit I haven't really looked much. Try to understand our objections. If your device rattles and jumps around, people will say it is propelled by friction, and they probably will be right. If you put it in a box to prove it's not propelled by making wind and have it produce lift, people will say it is a hot air balloon. Simple solution there: Turn it around and make it pull down. When developing new ideas, think a bit about how the effect you expect would influence known systems. The whole Earth in its orbit (for big masses). Electrons in an atom (for high rotation rates). Those work as we expect them to, so if your idea says they should do something different, it's probably wrong and you should look elsewhere first. For proving that it's not friction against the ground that drives your device, your own suggestion is probably the best: put it on a floor that is itself mobile. You only need to make sure there is less friction between that second floor and the real floor than between your device and the second floor. If you use an air table or rail, you have the problem that any tilt will produce thrust via uneven airflow. The pendulum test can only give good results if the device does not shake too much, and you need to be able to reliably track the center of mass. (*) and boy would we be in trouble then. Our understanding of Quantum Mechanics relies on that.

Yeah, something is missing from the picture. A simple mass on a string has two degrees of freedom. A fixed-rotation-speed gyro on a string has four (edit: relevant degrees of freedom in both cases). True, two of them will be driven by precession, but what about the other two? I'd need to see a demonstration on how they either vanish in puffs of logic smoke or are driven by precession, too. They absolutely should still be there and behave like the regular pendulum degrees of freedom.

That would be due to the simple fact that the VEEG guy does not understand how air works. Sensing shapes, yes. Sensing forces, no. We are comically bad at those, especially when judging small forces while simultaneously applying force. Never trust your body on this. Just look at the "lift 40lb flywheel" experiment.

Yeah, energy has no direction. The potential energy does get transformed into kinetic energy, which also does not have a direction on its own, but of course it needs momentum to exist. That momentum, at first, is only directed sideways. That direction then gets turned forward with the external help of the wheels blocking sideways motion and Jone's hand. Without the hand, I'm sure the cart would move a bit backwards and then forwards again. I expect that in the original, genuine presentation, that forward movement was indeed bigger than the previous backward movement. The reason I expect that (apart from the obvious one that nobody would have been impressed otherwise) would be friction, of course. As the sideways motion is slowed down, the wheels are pushed sideways and have a bit (how much depends on the quality of the wheels) more friction than later on when the forward moving gyro is slowed down again.

No, I meant what I wrote. It has no total momentum at the time of the initial pendulum release, when the arm is still raised. I'm not counting the spin, of course, as that does not contribute. The speed the device moves in the end is about what you would expect if a good chunk of total potential energy from the elevated position of the gyro gets converted into kinetic energy in the form of forward momentum. I think you are underestimating the speed of the gyro's forward jolt. I was wrong about one thing, though. You can always see what at least one of his hands is doing, the hand that holds and releases the pendulum. He never just releases it. He keeps it on the device for about as long as the forward acceleration lasts. Why does he not simply let go? Why don't they at least use a string to release it? No need to burn the string, just hold it and let go. I know this is just a reenactment for a TV documentary, but it's now entirely unconvincing. No reason to believe even that he is not actively pushing. (Not because he is a fraud; I'd rather suspect the director instructed him to make it a little more convincing for the audience.)

It has non-zero momentum at the time the wagon is released. At the time the gyro pendulum is released, it does have zero total momentum. Then, several things happen quickly. First, potential energy is converted into kinetic energy as the pendulum swings down. The sideways momentum required to do so is provided by the wheels which can't move sideways. Then, precession kicks in; the sideways momentum is transformed into forward momentum. The sideways momentum difference is again provided by the wheels, the forward momentum provided by preventing the wagon to move backwards. Then, the wagon is released at a time where it has total forward momentum. If you were to place the wagon completely free to move forward and backward, with the pendulum held sideways by a string, with ideal wheels completely free of friction even when pushed sideways, and then burn the string, the following would happen (if my explanation above is correct): The wagon would jerk backwards, then forward again, wobble a bit, then stop in the starting position. The analogy with the simple pendulum wagon was not meant to be complete, just equivalent. To get from the pendulum to Jones' device, you can make the following iterative changes: 1. Replace the pendulum with a ball rolling on a track that follows the same path as the pendulum weight. The ball rolls from the back of the wagon forward, release the wagon as it is at the lowest point of the trajectory. 2. Bend the back part of the track sideways. The ball now rolls sideways first, but then forward. Release the wagon as the ball is moving forward completely. 3. Replace the ball and track with Jones' gyroscope pendulum. Precession forces the gyroscope onto a similar path as the ball. You never have to time the release. It's enough if you block backwards movement of the wagon. That will automatically release the movement at a suitable point.

Alex Jone's device does not "work" for any meaningful sense of the word. It is as good at providing forward thrust as a wagon with a pendulum on it that you release when the pendulum is at its lowest point.

Conventionally (without quantum gravity), vaccum fluctuations happen at all frequencies and thus have no lowest size limit. Of course, we expect that to be in need of correction once you hit the Planck scale, but that's also the scale where we suspect the final evaporation to take place on... so no, this is very unlikely. It could be that Hawking radiation generation is heavily suppressed in the final stages and that they take longer to decay than simple extrapolation would make you assume, but completely inhibited? Probably not.

How toilets work in space. (Or, of course, if it's not on the curriculum already in your region, how moon phases or eclipses or seasons work.)

When the gyros are off, they don't resist the rotations you force on them as much. So less force is required. Thus, via reaction forces, the wheels are pushed around less, which results in less friction. Since we consider that the source of your thrust, you get less of it.

Distance does not matter here, velocity is all that matters. Like with the rubber band. A long rubber band does not fling itself away faster than a short one. The hands are obscured again. Look, Laithwaite was a brilliant engineer. He could not turn this machine into a properly working continuous drive. He would have been, easily, if the strong visible reaction was actually the device pushing itself forward on nothing and not some one-shot effect from the setup. But thanks for a watchable version of the whole documentary. I'd love to! But unfortunately, I'm more of a theory guy. Plus, my wife would kill me. Our living space is still massively unfinished even though we're living here for 18 months. Wardrobe door missing, cables coming out of the ceiling where a lamp is supposed to go (her fault! She doesn't know what kind of lamp yet.), that kind of stuff. So if I now started building contraptions... My only realistic chance at playing with this stuff comes a bit later when my daughter is old enough so I have an excuse to get a mechanics set of some kind.

It is enough if he blocks the device from moving backwards as the arm starts moving. You can see a bit what would happen if this were to be converted into a cyclic thing: at around 1:17, when the arm swings up again, the cart rapidly decelerates. It would not gain speed from a cyclic, internally powered process.

Holding, I said, not pushing. The thing is, the contraption does not go through a cyclic motion, it's a one shot movement, then it needs manual resetting. That it moves after being let go proves nothing. Rubber bands do it better if you fire them with your fingers. It's the same here. He moves the arm sideways, then he lets go of the arm. The arm centers and precession of the gyro forces it forward. As it moves forward, he lets go (and probably gives it a push unconsciously, because that's what muscles do, but it does not matter much whether he does or not). At that moment, the total momentum of the machine is non-zero, it's just not equally distributed. The frame is stationary while the arm with the gyroscope is moving forward. The frame starts moving when the momentum redistributes itself internally. And his left hand is mostly obscured by the device in the take you are describing. No, I did not do a frame-by-frame analysis, but it seems to be impossible to tell when precisely he is letting go. He definitely has to hold the device while he pushes up the arm with the gyroscope. Yes, gyroscopes can be weird, especially if they are on a off-COM pivot or constrain it so that you block its natural precession movement. Absolutely recommended watch: Laithwaite's lecture. I used to be dressed like the audience members as a kid! The experiment at the end of part 4 is especially baffling. Edit: I what I recommend it for is the experiments. Not necessarily the lecture.

diomedea: Yes, I get all of that. Two problems: 1. The device is not fixed on a rail. It loosely sits on the ground/a rail. It has no fixed pivot axis. 2. The total force of any gyroscope will always be zero, you only have torque to work with at first. You need a pivot to convert torque to a force. Well, one problem. You don't have what you need. The device could only fall over. (Only escape: see Edit of last post) I'd very much like to see a proper gyrocompass (with the gyro in a regular bearing; special bearings or active controls can of course accelerate things, anything that reacts and enhances the precession would be cheating here) align itself to Earth's axis within minutes. I've only seen toy demonstrations with Earth replaced by a spinning plate, and there it takes several rotations (so, days) to settle.

No, it really could not. Yes, the individual forces in play can be tremendous, but you need a way to transfer them into motion. Loose wheels can't do that. Keep in mind the effects from earth's rotation are not magic; they do not work without mechanical contact. There simply is not enough of it in the setup at hand. With only (idealized, frictionless, unable to receive torque from the device) wheels providing that contact, at best, you can get your fancy device to fall over. Slowly if you only rely on earth's rotation, quickly if you actively tilt your gyroscope (but then it would also fall over on non-rotating bodies). But let's not argue about that any more. You proposed a relevant test: Align the track in north-south direction and you say it will stay put? Well, I say it won't. M Drive: Please do it You can potentially shut up one critic. Edit: Well, actually, if you put your device on an absolutely rigid track that perfectly follows Earth's idealized curvature in an east-west direction and you have perfectly frictionless wheels, you can turn any torque gyroscopes may provide into a westward net force by essentially grabbing on to the curvature... but that force is limited by the weight of the device times its length divided by Earth's radius. So a tiny force. To actually make that move, your coefficient of friction of the wheels needs to be lower than the ratio of the device's size by the Earth's radius. Good luck with that! You can improve your odds by rigidly clamping your device to the track with wheels coming from all sides, like roller coasters do; that removes the limit on the forward force, but not on the coefficient of friction. That can be gotten rid of by not letting the track follow Earth's surface, but simply being a regular circular track. Or get rid of the track and mount the device on one end of a long pole, with the other end of the pole on a pivot. Anyway: Clearly not what we are seeing here.

The same objection applies. How fast does a gyrocompass' axis rotate relative to a fixed laboratory on earth? How fast does the Foucault pendulum shift its plane? In both cases, the rate of change is linked to the angular rotation speed of the earth. At best, you get one full rotation per day. Unless you design your device to be specifically sensitive to earth's rotation it is very, very unlikely to matter for timescales of a couple of seconds.

Relevance of Coriolis forces essentially scales with the size of the system and time. Contrary to popular belief, they are not responsible for which way the vortex in your sink rotates. Likewise, they have no significant impact on the machine in question. It simply is too small and the timescales are too short. Edit: thinking further, size does not matter directly. But larger systems tend to operate on longer timescales.

That guy is clearly holding on to his contraption at least during the first half of its movement in every run, while the gyro arm is coming down and moving forward due to the precession. He is applying the forward force during that time. Unconsciously, I am sure. Gyros and muscles are great ingredients for for some compelling psychological trickery, see the Powerball. That's harder to analyze, but in addition to the usual friction effects one would suspect, he is using a fuel powered model engine with the fuel stored in the device. Not only does the engine produce thrust via intake and exhaust (to his credit, the exhaust seems to be going upwards), it gets lighter over time. Your own device rattles quite a bit as the wheels jump around. It has plenty of opportunity to give itself a boost when the wheels clash with the rails sideways. At the very least, you need to completely eliminate ground friction; there are various air cushion solutions available, just make sure you don't accidentally turn the air cushion into the propellant and that the cushion never breaks down. And to eliminate the suspicion you are just building the world's most inefficient fan, put all of your moving parts inside a (transparent, if you like) box. The effect will go away then. People have been trying to build such devices from common hardware components since basically forever. This handy chart applies: https://xkcd.com/808/