12 times more output than input, dual mechanical oscillation system !

[kolbacict]

Well, that's just my guess ...It has not yet been tested by experience.
And we will not repel with rocket fuel, of course.
And for example with magnets.

[Floor]

push the pendulums away from one another below when they have maximum speed (maximum kinetic energy).   The Oberth effect. ?
https://en.wikipedia.org/wiki/Oberth_effect

That IS lifting.  Lifting is both, against gravity and acceleration.
Against gravity alone is only balance, additional force magnitude causes acceleration.

Oberth effect,  Hmm.

Oberth effect is due to interception with an all ready moving planet. The additional speed
of the rocket comes from the speed of the planet's motion. Not from the rocket's fall
and subsequent escape from the gravity, those two cancel out.

It's something like swinging past a moving auto while on a skate board and gabbing the bumper.

One catches the bumper because one is moving, but also because one has an oblique
interception course. 

If not for the planet moving faster than the rocket, the rocket would not gain a net
speed increase.

       PS

Correction that would be a "sling shot maneuver " I was describing above.

Oberth effect. Could it apply to the pendulums ?
Wikipedia / LankaIV quote

"Rocket engines produce the same force regardless of their velocity. A rocket acting
on a fixed object, as in a static firing, does no useful work ON THE ROCKET.
The rocket's stored energy is entirely expended on accelerating its propellant in the
form of exhaust.

But when the rocket moves, its thrust acts through the distance it moves.

Force multiplied by distance is the definition of mechanical energy or work.

So the farther the rocket and payload move during the burn (i.e. the faster they move),
the greater the kinetic energy imparted to the rocket and its payload and the less to
its exhaust. "

This only applies to a reaction / thrust drive I think ?  Interesting.

[Floor]

Very cool  kolbacict / Lanka...
Some days I'm slow on the uptake...

[Floor]

May be if the applied force originates from within the pendulum bob.

[kolbacict]

Well, jet propulsion is movement by throwing some mass backwards.
Using an energy source (such as rocket fuel). Rocket fuel doesn't suit us, of course.
I guess it doesn't matter what could push out the mass. Let it be magnetic (electromagnetic) forces.