Directory:Bob Kostoff Gravity Machine

Lasted edited by Andrew Munsey, updated on June 14, 2016 at 8:51 pm.

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Image:BobKostoff gravity machine.jpg

Bob Kostoff, a Canadian, has created what he calls 'The Gravity Powered Machine', a self-sustaining engine that costs less than half of a small wind turbine. The machine, which requires only a little juice to get it started, looks much like a teeter-totter but works like an overbalancing gravity wheel. It is using a series of sliding weights that, with the help of the earths gravitational pull, force the unit to continue spinning around in a circle.

Kostoff, who has built some five working prototyptes, says the engine provides as little as 10 foot-pounds of torque or as much as hundreds.

Validation? : This device has not been independently validated that we know of.


Official Website - video links - old site

Latest Developments

Oct. 17 2008

Saw this on the site home page:

New Machine Specs:

: Length: approximately 8 feet

: Width: approximately 4 feet

: Height: approximately 6 feet

: Weight: 3850 lbs

: Torque: up to '3000 foot lb'

And this was on the Overunity forum:

: "Bob's new demo unit is suppose to be the start of his initial production units. Apparently he was successful in getting a local company to start producing them. I'm hopeful that his website will present clear photos or video of its operation."

Oct. 31, 2007

Bob wrote: "Thank you for your interest in the machine. I am trying to respond to

all the Email that I have received, but that in itself is a big job.

I will be posting on the web site the progress of the construction of

the machine I am building at home. Hope to have it completed soon. It

will generate around 1200 foot lb. of torque @ 40 to 50 rpm. I have a

20K Watt generator that it will power."



(1 minute)

free energy gravity wheel - (YouTube May 11, 2007)

(Right Click, Save Target As...)

How it Works

On May 11, 2007 Bob Kostoff wrote:,2326.msg31148.html#msg31148

The machine is totaly independent. It requires no external power.

It works the same as the unbalanced wheel. The trick is to

get the weight back to recycle it. There are 3 procedures I have used to do this.

The air cylinders I use as a shock absorber, similar to that in a car and it also stores

a bit of energy that locks the 2 weights together almost at the bottom. A set of springs are also at the end of the rotating wheel to absorb the impact of the weights.

It trips a leaver that activates a pin that acts as a pushrod to return the weights.

When the weights are attached they only need to be returned 1/2 the distance then centrifical force takes over and then they start to accelerate to the other end. The closer to the half way point the 2 weights get the less energy in needs to move it.

Once the weights are past the balance point they accelerate and generate many times their weight which creates the the energy needed. The faster rotation the larger the force. Without the springs and shock absorber it would destroy itself.

Hope this will help, and I am glad to share it with you.