Basics
Movement is the change in the position of a body in space. Time passes and the body is on a certain path during this process. If it is a circular path, it is called a rotational movement. In our mechanized world it probably has the greatest importance. In a gravitational drive, the goal is to convert the downward force of the Earth's gravity into rotational motion. A comparable situation occurs with the internal combustion engine or the steam engine. The movement of the piston is converted into a rotary movement via the connecting rod and the crankshaft.
G1 = G2
How can one imagine such a gravitational drive? Since the masses of a wheel are usually evenly distributed and the axle is at the center of gravity, it is not moved by gravity. In this case, the downward attractive forces are equal on the left and right sides of the wheel and thus ensure balance. The following two drawings represent this condition using the masses M1 and M2.
Masses in equilibrium
The above arrangement is also in balance because the axis is at the center of gravity.
This is not the case with a beam balance, which may come to mind here. The axis is intentionally positioned higher than the center of gravity marked in red. Since the latter always wants to take the lowest position, the bar automatically turns horizontal when it balances. This process is a consequence of the lever principle.
Both levers on the beam balance are only the same length when horizontal.
The sketch above shows that a deflection leads to a lengthening of one lever and a shortening of the other. This ensures the desired effect.
G1 < G2
To stay with our wheel, if the distance to the axle at M2 is changed, for example, or if this mass is increased or decreased, an imbalance arises. (The following is shown in the first drawing by the longer lever, in the second by the enlarged mass.)
The gravitational forces acting on the wheel are no longer equal and therefore cause it to rotate.
After a short time, however, a new equilibrium is established.
G = G1 + G2
The wheel has rotated 90° due to gravity. In practice, however, not much can be done with this alone.
The goal is to create a constantly rotating wheel that could be used to drive an electricity generator, for example.
Many amateur inventors start their experiments with the horizontal lever. What is often overlooked is that this is only an ideal exceptional case for use with wheels. The sketch above illustrates that a weight placed at the edge only works at 100% lever length when it is in the horizontal position. As the wheel rotates, the lever quickly becomes shorter and therefore the usable gravitational effect becomes smaller. Where, during experimentation, masses are moved to the edge in order to create the necessary imbalance, this regularly leads to disillusionment.
This is also always unpleasantly noticeable when the imaginary straight line on which the weight and “counterweight” are located does not pass through the center of the wheel. This case occurs frequently when experimenting.
Although the left weight only uses half of its possible lever length, it is not lifted as far as expected, but rather the wheel comes to a stable state at about 40% of the horizontal lever.
So if you want to implement a wheel drive by extending the lever, you first have to find a way to make the difference between the length of the power arm and that of the load arm as large as possible. As the above sketch shows, to make optimal use of the leverage (in theory) this is done by starting the extension of the force arm at around 0° and ending at 45°. The shortening of the load arm should begin at 135° and end at approximately 180°.
Here, however, seemingly insurmountable difficulties arise. How should the red colored weights be moved against the downward force of the earth's gravity by the same gravity in the direction of the green arrows (towards the periphery or towards the inside of the wheel)? The external weights would not be able to do this because after deducting friction and air resistance, their balance would be negative. In addition, it is often overlooked that a weight that lifts another using a lever can contribute (almost) nothing to the downforce on the side of the wheel during this time. A solution to this question would be to end the search for eternal motion.
As already explained at the beginning, a wheel is always in balance when its masses are evenly distributed and its axis is at the center of gravity. A gravitational rotation requires a disruption of this equilibrium. If this is done once, the part of the wheel with the greatest mass soon occupies the lowest point, thus bringing it to a standstill again. If this is to be avoided, the mass in question must be raised again and again in order to have its effect again. At first glance, it seems impossible to accomplish this process using gravity alone. And yet Bessler must have found a way to achieve exactly that.