Fuel-less Flight.

In case you are thinking -- perpetual motion device. Here is the explanation of why that thought is an incorrect assumption. Any qualified scientist knows that the use of heat as a power source in a closed thermodynamic cycle results in entropy – the loss of a portion of the heat energy due to friction, heat conduction, etc. The result is that each time a cycle is completed there is less energy returned as an output than went into the process; therefore, perpetual motion is correctly deemed to be impossible.

A scientist also knows that the world in which we live is not a closed system. There are forces provided by our natural environment, such as sunlight that produces heat energy and can produce electricity via photovoltaic modules, wind that may be harnessed by a wind turbine to produce mechanical drive that can be used to generate electrical power, used to compress air, or used to drive a hydraulic pump, and there is geothermal heat energy can produce electrical power, and yes the forces of gravity that may be used to our benefit. Just because scientists in the past failed to create practical devices that employ gravity does not mean that gravity cannot be used. Hunt has discovered how to harness gravity by the combined use of gravity’s dual properties – buoyancy to create an upward motion and gravity acceleration to create a downward motion – in an alternating cycle. However, other environmental energy sources will be harnessed by the gravityplane and used in conjunction with the dual properties of gravity, such as solar power, thermoelectric power generation, temperature differentials, current differentials, and pressure differentials, etc.

Ballonets
Ballonets are air-filled bags that are located inside the envelope. The blimp has two ballonets, one fore and one aft. The ballonets are similar to the ballast tanks of a submarine. Because air is heavier than helium, the ballonets are deflated or inflated with air to make the blimp ascend or descend, respectively. They are also used to control the trim, or levelness, of the blimp.