Gyroscope Precession and Hidden Reactions: A Step-by-Step Guide

Introduction to Gyroscopes and Precession

Everybody knows what a gyroscope is. Oh, you don’t? Well, it’s quite simple—it’s just a spinning wheel. Most people, physicists included, already know what gyros do, but when certain forces are applied in certain ways, you can make them do some pretty unexpected things… well, almost anything.

For those who do not understand how gyros work, I will try to break it down the best way I know how. For those who are “in the know,” you can skip this part.

Let’s say we have a simple wheel with an axle going through it from left to right, and we are holding each side in front of us. Now, if we try to lift the left side up and push the right side down, the gyro will essentially try to move the left side forward and the right side backward.

Same thing if we try to move the left side of the axle forward and the right side backward—then the left side will move upward and the right side will move downward.

If you haven’t noticed by now, the gyro is actually trying to “respond” by moving at a 90° angle from the initial torque we give it. That is its nature. This is referred as gyroscopic precession.

At this point, most people yawn and move on.

Then we have the crowd that says the gyro should lose weight and move upward into the air against gravity. We all know that’s impossible… or is it?

For the most part, it’s been proven over and over again that a gyro does not lose weight—because it just doesn’t.

The Gyro’s Unique Ability to Orbit Its Pivot

But one thing it does do, which is a bit strange when you think about it, is this: we have a very large mass with a lot of weight (weight only applying here on Earth) that has the ability to orbit around its own pivot, where the pivot itself weighs practically nothing.

Now wait a second—this is usually the other way around.

Let’s say you and I were floating in space. Let’s say I weigh 1000 lbs (yeah, I know—that’s a lot), and you weigh 100 lbs.

Now tell me: if one person pushes off the other, who is going to move more?

Logically, the one with less mass will move more easily, while the one with more mass will have a harder time moving. So if I push you, you go flying off, and I barely move in the opposite direction. It works the other way around too—if you push me, you send yourself flying while I barely move.

I think that point is pretty clear.

So now we ask: is it possible for this to work the other way around? That the lighter person could push on the heavier person and move that person significantly, while the lighter person hardly moves?

For all intents and purposes, that’s practically impossible—logically speaking.

But what if we could do that?

Well, there aren’t that many things in this world that can do that, except one that I can think of—and that’s the gyro. It has the ability to rotate (orbit) around its pivot, and this is the crux of it all. The gyro, weighing thousands of times more than the pivot, can rotate around that pivot without moving the pivot one iota.

The pivot doesn’t move in the opposite direction; it just sits there, stationary in space. The only thing it does is rotate in the same spot. This is no different than the center of a wheel—it remains stationary, only rotating in place. If we had a wheel in space with a mass on its rim, and a motor with an equal amount of mass at its center, and turned it on, this is what would happen:

As the motor begins to turn the wheel, the mass on the rim will move, but there is a reaction, and the motor will begin to turn as well—it won’t stay exactly at the center. What happens is that both the mass on the rim and the motor orbit each other, just like a binary star system. There is nothing fixed at the center, so they end up rotating around each other. A new center of rotation forms between the motor and the mass, no longer at the center of the wheel.

So as you can see, keeping the center of the wheel fixed in space while rotating the mass around it is next to impossible—it just isn’t going to happen.

Here on Earth, we would normally fix the center to something rigid, like a table, and the weight on the rim spins around as expected. But in space, forget it—that ain’t happening.

Centripetal Force and the Rock-and-String Experiment

Another way to look at it is this: if we spin a wheel very fast with a mass attached to its rim, and the center is fixed to a table, we can rotate that mass around the center. But during its spin, if we suddenly detach the axle at the center from the table, the entire system would fly off in a straight line, taking the center along with it. This is especially true if the wheel and the center are extremely light.

This brings us to the simple rock-and-string experiment, where we attach a rock to a string and spin it like a lasso. At this point, you may be asking, “What does that have to do with anything?” Don’t worry—I’m going to tie this all together so it makes perfect sense.

But first, I need to explain a few things so that it all makes sense at the end. As rudimentary as the rock-and-string experiment may seem, we need to understand these forces first.

At the center of anything that rotates is what we call centripetal force. This is a very real force. It’s a “center-seeking” force that acts on an object moving in a circular path, directing it toward the center. It is essential for circular motion, constantly changing the object’s direction and keeping it from flying off in a straight line.

In the rock-and-string example, your hand is “external” and provides the necessary centripetal force for the rock. When you release the string, the rock flies off in a straight line—this is tangential motion. It’s simply inertia, or linear momentum continuing in the same direction.

This is exactly the same as our wheel with its axle attached rigidly to an external table.

Now, about “centrifugal force.” In an inertial frame, it’s not a real force acting outward—it’s what’s called a fictitious or apparent force. What’s actually happening is inertia resisting the inward pull. So in the rock-and-string experiment, there is no real outward force—only inertia and the inward centripetal force.

When we release the string, the rock keeps moving in the same direction it was already moving. If there were truly an outward force, it would have to suddenly shift 90° and move directly away from the center—but that’s not what happens.

Another way to look at it: imagine letting the string slip slightly through your fingers at the 12 o’clock position. The rock would travel in a straight briefly, then when you grip the string again, it continues in a circular path—but now in a slightly larger circle. To bring it back to the original smaller circle, you would have to pull it inward.

That inward pull, continuously applied, is exactly what centripetal force does.

One more way to look at this: if the rock is simply moving in a straight line—let’s say from left to right—and we slightly change its direction by rotating it clockwise, then it will now be moving slightly downward, but still in a straight line. If we keep doing this, changing its direction step by step, eventually it will be moving straight downward—still in a straight line at each moment.

This is exactly what centripetal force is doing to the rock—constantly changing its direction so that all those straight-line motions combine into a circular path.

From Rock Experiment to Gyro Constraints

Whew! Now that we’ve got that out of the way, we know that we need a centripetal force in order to rotate something in a circle. To do this in space, we would need a very large mass to rotate a much smaller mass—this would behave exactly like a wheel spinning a mass on its rim with its axle rigidly connected to a table.

But we are still trying to figure out how to get a much smaller mass to move a much larger mass without moving that smaller mass.

With a single gyro, we still can’t do this either, because we need a “constraint.” But I’m going to show you how we can get the more massive gyro to orbit around its less massive pivot in space, where the pivot has next to no mass. This is where it begins.

First, let’s look at a gyro hanging on a string. Everybody’s seen this—a gyro on a long axle, with the other end of that axle attached to a string, which is attached to the ceiling. The point where the string attaches to the axle we’ll call the “pivot.”

The string stays vertical, and when we drop the gyro, instead of falling straight down, it rotates around the pivot horizontally, while the pivot remains perfectly stationary. Here, gravity does the work of “tilting” the gyro and its axle downward. The response is a horizontal precession—the gyro reacts at a 90° angle.

Ok, nothing special is happening here yet. But this shows exactly how the gyro operates and what is needed. So far, we have an initial action, which, for all intents and purposes, is a Newton action/reaction pair. These obey Newton’s third law perfectly. For those who don’t know, it states: for every action, there is an equal and opposite reaction. Everything in this world obeys this like clockwork orange—there’s no way around it.

BUT!

Now we can take this simple action/reaction pair and see the outcome: the gyro orbits its pivot without the pivot visibly moving in the opposite direction. Wait a second—I thought that was supposed to be impossible according to Newton’s third law? Well, it’s definitely not violating it. Here’s what’s actually happening:

The reaction is definitely there, but it’s hidden at a single point in the pivot. I like to refer to this as the “singularity.” You can have a reaction that doesn’t produce any visible motion in its counterpart—and that’s exactly what a gyro does and is EXACTLY what we need to accomplish the end result which you will soon see.

The Gyro-and-String Experiment

The gyro-and-string experiment is a perfect example because it shows us everything we need to know. It demonstrates that we need an opposite and equal reaction, which generates a downward torque (rotation). It’s also a very good simulation of outer space, because gravity only acts vertically—not sideways. So if there were any horizontal (sideways/lateral) motion, we would easily see it at the end of the string in the pivot.

We know that the string and pivot weigh essentially nothing, so if they were to move in the opposite direction of the horizontally rotating gyro, we would see it immediately. And guess what? That’s exactly what we observe: the pivot does not move out of place at all. It remains perfectly stationary in the horizontal plane as the gyro orbits around it. BUT we still need an opposite and equal reaction to make this happen.

Ok, so before I said I was going to show you how to accomplish this in space. We know we can’t push off space itself, so how do we create the necessary “constraint” to make the gyro orbit around its pivot? With a single gyro, it wouldn’t work—there is no gravity in space to “tilt” or torque it downward. So what do we do?

We create the necessary opposite and equal reaction by using two counter-rotating gyros and making them orbit around each other. We do this by attaching their axles to two individual pivots, which are connected to a central hub. This hub is a motor positioned between the two counter-rotating gyros.

This is entirely feasible in space—motors on the International Space Station and on satellites do it all the time.

A motor, in its most basic form, has a rotor and a stator, which actually move opposite to one another. They counter-rotate, and this is how we rotate the two gyros. Since the gyros are counter-rotating, they will precess in the same direction around their pivots. Let’s give them a direction in space and say they both rotate (precess) upwards around their pivots. Essentially, we’ve knocked out two birds with one stone.

Now we’ve figured out how to make a single gyro orbit its pivot by having two gyros constrain each other, allowing each to orbit its own pivot. This is where we get into the meat and potatoes of the concept.

Gyro Constraints and Centripetal Analogy

So just like how the axle at the center of a wheel has to be fixed to a table in order for a mass on its rim to rotate in a circle, that is exactly what a gyro does around its pivot—but without the pivot being fixed to anything. The two gyros are effectively fixing each other in place, as if they are bolted to a table.

The center of a wheel provides the centripetal force and requires something external to hold it fixed, just like the hand does in our rock-and-string experiment. Now we have two gyros that we can rotate horizontally with a motor, which keeps the motor fixed at the center. This causes the gyros to rotate, or precess, upward around their pivots.

In other words, they both orbit their own pivots, while the hub—the motor—remains perfectly stationary. This behaves like a centripetal constraint, but now it exists entirely within the system, even in space.

Revealing the Potential for Motion in Space

At this point, this is where most people say, “So what?” Even though this is an amazing accomplishment in and of itself, what’s the point?

Well, hello? McFly? Anybody home? McFly… McFLY!

Here, we have just figured out how to move a very large amount of mass using a very small amount of mass. Isn’t this exactly what we were trying to figure out?

At this point, you might start to see how this concept could be used to move objects in space—even from a resting position—but we aren’t quite there yet. First, we must ask ourselves: what is the closest thing we can do that mimics an object suddenly accelerating, without actually pushing anything out the back of it, even from a resting position?

What else can we do that remotely resembles this? Well, we have our rock-and-string experiment. We can spin the rock up to a very high velocity, just like a spinning wheel where our hand provides the centripetal force (the center of rotation). I mean, if you covered up this rock, nobody would ever know it’s spinning. For all intents and purposes, it would appear at rest.

Then we let go of the string and watch the rock take off at a very high speed in a straight line (linear momentum), pulling the string along with it. But there is no way to do this in space using an entirely internal system. I know, I went out into space and tried it myself… not really, I’m just kidding. But seriously, you really can’t do that.

But wait a second. What about the two gyros? They can mimic the rock-and-string experiment perfectly—and you don’t need anything external to do it either. Here, we have two large, massive objects moving around something with very little mass—the motor at the hub—without it even moving visibly in the opposite direction, and all of it happens internally!

Converting Rotational Motion into Linear Momentum

At this point, a single eye of most physicists might become lazy and float off to the side. Here, a slight amount of critical thinking is required. Most people think it's practically impossible to convert angular momentum into linear momentum. In simpler terms, most people do not think it's possible for an object in space to go from rotating to moving in a straight line.

A fine example is if you have two masses—let's say rocks—tied to each other with a string and spinning in a circle so that they orbit each other. Then, suddenly, cut the string: they both fly off in straight lines, of course, but only in opposite and equal directions due to Newton's third law. Traveling through space this way is impossible, as the opposite-and-equal action/reaction pair is painfully obvious.

In our rock-and-string experiment, the rock has not only angular momentum (rotation) but also tangential velocity, or linear momentum, at any single point around its circular path—but it’s trapped in a circle due to centripetal force. What do we do? We simply cut off the centripetal force by letting go of the string. Now the rock is free to travel in a straight line, pulling the string along with it.

We have just converted the rotation of the rock into a straight line of travel. However, we still need an external centripetal force to achieve this. Perhaps by now, you’ve figured out where I am going. In the exact same way that the rock goes from a circular path to a linear path, we can achieve this with the two gyros. How? Very simple, and this is imperative to the operation of the whole system.

Impulsive Torque and the Pulsed Torque Method

We cut off the centripetal force of the gyros in the middle of their upward precession. How? Very easy: we simply quit applying the horizontal torque—or, more simply, we turn the motor off. This shuts off the gyroscopic force, no different than releasing the string in our rock-and-string experiment—effectively identical!

This creates what I am coining “an impulsive torque,” or “torque impulse.” We need a pulsed torque: turn on the motor to horizontally rotate the gyros, generating gyroscopic forces, which causes the gyros to precess upward. Just as they reach the midpoint of that upward motion, we cut the motor and the gyroscopic force—a true “pulsed torque.”

Some might say, “Oh, but if you stop the gyroscopic force, the gyros will stop.” Not so. This is where most people quit investigating and lose interest—they fail to consider the possibilities.

What happens is that the gyros want to keep moving. They already have velocity. Cutting the gyroscopic force does not stop them; momentum has already built up just before the motor shuts off.

I personally tested this on the bench. I used a skateboard wheel as a hub on a vertical bolt, with a pivot attached to the hub and a bolt as an axle. On the other end of that axle was the gyro. Dropping the gyro allowed gravity to torque it downward, and it rotated horizontally around the hub—no big deal.

I added a simple L-shaped aluminum bar attached to the hub. This captured the gyro if it slowed down due to bearing friction, stopping further downward torque. Once gravity could no longer tilt the gyro, there was no more gyroscopic force.

And yet—it kept rotating horizontally. This showed me that even without ongoing gyroscopic force, the gyro retained significant inertia and tangential linear momentum—enough to potentially pull the hub along, if the hub is light enough.

The torque impulse creates a scenario identical to releasing the string in the rock experiment. The gyros precess upward, then stop precessing, and they pull the pivots and hub upward along with them due to linear tangential momentum. The system now begins traveling linearly through space at a constant rate.

This is not constant acceleration—only a one-off pulse. It demonstrates the basic mechanism to move an object linearly from rest, equivalent to the rock taking off in the rock-and-string experiment.

Implications for Fuel-Free Space Travel

This one-shot, “sling-shot” effect requires no fuel—only electricity to power a motor at the hub and two more motors for the gyros. Repeating this pulsed torque could, in theory, generate additive accelerations, reaching extremely high speeds with the same force per pulse. But that’s a discussion for another post.

It’s important to note—nothing I’ve described here violates the laws of physics. Every step, from the counter-rotating gyros to the pulsed torque, is completely allowed by classical mechanics. The gyros are simply converting rotational motion into linear motion internally, without pushing against anything external.

And yes, those pulses are additive. Each properly timed pulse builds on the momentum generated by the previous one. In other words, repeated impulses of the same magnitude would indeed accelerate the object further, step by step, in perfect accordance with physics. This is the foundation for moving an object from a resting position to constant motion through space, and it opens the door to a propulsion method that requires no fuel and only electricity.

With this understanding, we can see how the simple principles of rotation, precession, and pulsed torque combine to create a completely new way to move through space. From the humble rock-and-string experiment to massive gyros precessing in perfect harmony, the concept is elegant, fuel-free, and entirely grounded in the laws of physics. This is just the beginning—repeated, carefully timed pulses could allow for additive acceleration, opening the door to high-speed, electricity-powered space travel, all achieved internally without pushing against anything external.