By:  Robert D. Hunt

            We humans can rarely invent any process that nature does not already use.  Most of the science we know today merely copies nature.  Our thermodynamic laws were formed by observation of nature.  They are not proven, merely not disproved.  Within this section of our website you will be taught a new science that mimics the earth's weather, by harnessing the dual forces of gravity -- buoyancy and gravity acceleration.  Harnessing gravity may be more technically described as the science of harnessing mass differentials.  High density mass falls within a low density lifting fluid, like rain falls from the sky, and low density mass rises in a high density lifting fluid, like a bubble rises in water or helium rises in air.

            The science you are about to learn disproves two well known precepts: (1) that gravity is a conservative force that cannot provide useful power; and, (2) the Carnot Efficiency that is the maximum efficiency that may be obtained by any power cycle that only refers to heat energies and does not take into account any other form of energy that may be created in a power cycle, such as energy gained from harnessing mass differentials.  Both of these precepts are proven to be incorrect by the mathematics of a new Hunt power cycle presented herein that harnesses the forces of gravity and all scientists know that mathematics do no lie.  Further, it should be noted that gravity is available for our use in open cycle as part of our environment on the Earth and the use of gravity does not involve heat input, as in a conventional power cycle such as the Rankine Cycle. Helium and hydrogen rise within the atmosphere without the need of being heated because of their light weight alone. Hydrogen is the only substance found in space as the molecules are so light that they can rise through the atmosphere into space, irregardless of its temperature so long as its not so low that the hydrogen is liquefied, and without heat input.

            Actually, marine mammals have already demonstrated the use of gravity to provide power in their ability to migrate for thousands of miles without taking in food by sea gliding forward and downward, using gravity acceleration, then alternating to gliding upward and forward, using the force of buoyancy, to continuously move forward by the mere movement of a few muscles to compress or expand air trapped within their lungs in order to make a change from being heavier-than-water to being lighter-than-water, expending almost no energy in the process.  It has been estimated that the kinetic energy of motion output from sea gliding of marine mammals is on the order of two hundred times their caloric intake!

            The energy for the marine mammals to sea glide comes from harnessing gravity.  If a thermodynamic model of the migration of a marine animal is made, it would be deemed impossible, using heat input from caloric intake as a measure of power input as the energy input is only a mere fraction of the kinetic energy of motion achieved as an energy output.  Something therefore is wrong.  It isnt nature.  It is the Carnot efficiency formula that is wrong.  Marine mammal migration is an observation of nature that flies in the face of one of thermodynamics most important concepts, the Carnot Efficiency, as the efficiency gained by marine mammals to travel via harnessing mass differentials (the dual forces of gravity) is far greater than 100% which is the greatest percentage allowable by the Carnot efficiency.  The observation of the migration of marine mammals also proves that gravity is not a conservative force that is unable to provide energy for our use.

            Okay, we will eventually get to the gravityplane, but it is important to understand how the underlying science of the gravityplane works.  Having been given the preface above we will further demonstrate how gravity is used by nature in forming our weather and how we can make a useful power cycle that mimics how our weather works that is presented next.

How Our Weather Works Using Gravity

           Everyone knows that heat energy from the sun vaporizes liquid water into water vapor that condenses into liquid water again high in the sky.  The water falls to land as rain or snow that melts to flow to the sea at lower elevation, which creates mighty rivers and lakes capable of powering hydroelectric power plants.  The latent heat given off by condensation of the water vapor into water heats up the surrounding air and this warm air rises within the body of colder air to create wind currents.  This process drives our weather; however, the weather could not be created without help from gravity. 

            If you examine the weather process more closely, you will realize that gravity plays a huge role in our weather cycle.  Yes, the process begins by the use of a small heat input to vaporize the water into water vapor, but it could not occur without help from the dual forces of gravity.

            Gravity exerts its presence on Earth as two forces, buoyancy and gravity acceleration.  It is buoyancy that allows the water vapor to lift up high into the sky in the first place.   Buoyancy is caused by the greater pull of the Earth's gravity on bodies of higher mass than on bodies of lower mass known as the Archimedes Principal.  Bodies of lower mass rise within a higher mass surrounding fluid and bodies of higher mass fall within a lower mass surrounding fluid. The water vapor is lighter-than-air, which means that it has less mass per cubic foot than air does.  At high altitude a temperature difference causes the water vapor to change phase to liquid water.  The water has more mass per cubic foot than air does; therefore, the liquid falls to the ground.  The process is driven by both temperature differentials and mass differentials. Our weather is the result of the combination of energy created by temperature differentials and mass differentials working together.  The process by which gravity is harnessed it to create mass differentials by forming mass having potential energy because of the location in which the mass is formed.

            The location at which the liquid water is created by the phase change creates a potential energy of height that is immediately converted into kinetic energy of motion as the water falls from the sky. This process also causes rain to fall on high elevation land that forms into flowing bodies of water. The flowing bodies of water may be harnessed for power via run-of-the-river turbines or power may be generated by hydro-damns that allow the flowing water to form a tall column of water that produces hydrostatic pressure that can drive a hydro-turbine to drive an electrical generator.

The Hunt Power Cycle That Mimics Weather

United States and International Patents Filed by Robert D. Hunt

Our weather cycle is mimicked by the Hunt potential energy power cycle disclosed below in which temperature differentials, mass differentials, and hydrostatic pressure work together to form a new power cycle that creates energy in the same manner as the weather creates power by using the difference in the temperature from a low altitude to a high altitude and using the dual forces of gravity – buoyancy and gravity acceleration -- in an alternating cycle, along with hydrostatic pressure.

Robert Hunt applied for U.S. Patent protection on this power cycle that mimics nature nearly a year ago after he began to discover the secrets of how to harness gravity by studying how nature uses the dual forces of gravity – buoyancy and gravity acceleration – to create our weather and the underlying principals from this patent allowed him to invent the gravityplane and an innovative new sea glider, which are powered by the dual forces of gravity that are used in an alternating cycle.

There is a natural temperature differential that occurs between lower altitudes and higher altitudes. This temperature differential with the help of gravity can supply all the power we will ever need. The heat energy to drive Hunt’s new power cycle exists in the thermal energy within the atmosphere at lower altitude that surrounds us and is available for our use 24/7. The energy is principally produced by solar radiation that is retained as thermal energy in the air that can be harnessed. With this new technology to harness gravity using power from solar heat (direct solar heat and thermal energy stored in the atmosphere) in the same manner that our weather does, there is no need to any longer burn fossil fuels.

The new power cycle is formed by a pipe that creates a closed loop that goes from the ground or even underground (to provide access to geothermal heat) to high into the sky and a temperature differential occurs between the bottom of the loop and top of the loop. In a single pressure closed system vaporization and condensation can occur with as little as five degrees F. difference; just as it does in heat pipe technology that is used to efficiently transfer heat from one location to the other. The temperature drops by approximately 5 deg. F. every thousand feet of altitude gained; therefore, more than adequate temperature differential may be readily attained by a system that could be built onto the side of a mountain, into the proposed new 1,700 foot tall World Trade Center Building to supply all of its power needs, or added to a pumped hydro-electric plant to eliminate the need for pumping water back to the reservoir.

A low-boiling-point-liquid or water at a reduced pressure is vaporized at the bottom of the loop using heat (thermal energy) from the ambient temperature air, geothermal heat, waste heat, or any other readily available low temperature heat source. The vapor rises to a condenser at height at the top of the loop via an insulated pipe that forms the left side of the loop. Two gases are present on the left side of the pipe. One is denser than the other gas and is used as a lifting fluid. The lifting fluid is non-condensable in the temperature range of the power cycle and will always remain as a gas. The second gas, which is much lighter than the lifting fluid, is the vapor to be lifted to height by the lifting fluid as it rises within the lifting fluid.

The two gases rise in a column and at the top of the column they flow through a gas turbine connected to a generator to produce electrical power from the kinetic energy of the two vapors. This portion of the cycle produces power and is a conventional Rankine Cycle that vaporizes a gas and then the gas flows through a gas turbine to generate power. This part of the process is like the weather that provides winds that may produce power via wind turbines. However, the Hunt Cycle disclosed herein provides an additional second power output by creating potential energy via a phase change of the vapor into a liquid that uses mass differentials to form hydrostatic pressure to power a hydro turbine to produce the additional power as is described below. This second process is also used by our weather to provide the energy to power hydro-electric power plants.

The low density vapor is readily condensable to the liquid state with a small temperature change. The condenser uses the higher altitude cooler ambient temperature air for heat rejection to accomplish condensation of the vapor into a liquid. The liquid formed by the condenser fills a tube with high mass liquid that is formed by the right side of the loop that extends from the condenser to the ground and hydrostatic pressure is applied to a hydro-turbine at the bottom of the tube. This process adds power to the cycle by creating power from mass differentials as the column of high mass water is formed within the low mass atmosphere.

A steady state flow is achieved as the vaporization rate, condensation rate, and liquid flow rate through the turbine are equal, thus the tube remains full all of the time and the liquid applies a hydrostatic pressure to drive the hydro-turbine to generate power. The output power of this potential energy power cycle is determined by the flow rate and head pressure. The head pressure can be increased merely by making the loop taller.

The vapor will rise to any desired height to reach the condenser so long as it is not allowed to cool and condense in the pipe along the way to the condenser. Therefore, the output power will continue to increase with the height of the system.

The height of the system determines the output power that readily changes by height when harnessing gravity and the input power is relatively fixed. Thus the nature of harnessing gravity is the process of forming the potential energy of height that is immediately converted to kinetic energy of motion or converted to hydrostatic pressure as used in Hunt’s power cycle and thus there is a direct correlation to height and energy output and not a direct correlation to input energy and output energy as thermodynamic power cycles that employ the use of heat alone, such as the Rankine Cycle. In the Rankine cycle a liquid is vaporized and the vapor powers a turbine. The output is fixed by the volume and pressure of the gas formed. In Hunt’s new power cycle, the output increases with the potential energy formed by the height of the liquid filled tube that produces hydrostatic pressure that increases with height. Thus a second power input is added to the cycle. The two energy outputs are the heat driven vapor power output and the mass differential power output of the hydrostatic pressure formed by the liquid filled column applying hydrostatic pressure to power the hydro-turbine that increases with height.

Innovative new power cycles, such as the Hunt Cycle presented herein, can literally change the world. The units can be placed anywhere and the hydro-turbines can generate electricity, which then can be used to produce pollution free hydrogen via electrolysis and the hydrogen can run fuel cells to power everything that is not connected to the grid, such as powering modes of transportation and providing power in remote sites, etc. The units can be built into the ground, instead of high in the sky, to take advantage of geothermal heat, which is especially effective in cold regions like the Artic Circle where the temperature differential from the ground to the ambient temperature air is substantial.

Hunt Aviation is interested in speaking with power companies or other parties interested in building prototype units of Hunt’s new power cycle that Mimics our Weather disclosed herein. If you would like to receive a full engineering report on the Hunt Power Cycle, please request it under the Request for More Information Form on this website.  


Modeling The Gravityplane In Air Using A Sea Glider In Water


            There is a lot that can be learned by creating a scale model of the gravityplane as a sea glider.  From existing sea glider technology, we have already learned that gliding is possible while rising upward.  What works in water also works in air.  Therefore, if a sea glider can glide upward, so can the gravityplane.  Another compelling reason the model the gravityplane in water is cost.  A gravityplane scale model sea glider may cost less than $200,000 and a working gravityplane may cost millions of dollars.

            The gravityplane must be very large in order to be lifted by a lighter-than-air lifting gas such as helium that provides a very low amount of lift, thus a small gravityplane can never be built and models of the craft will always be very large.  However, a scale model of the gravityplane can be built as a sea glider that is less than 30 foot long that will be capable of holding four passengers.  The sea glider can work in water at this small size, because water has a lifting capacity 821 times greater than the lifting capacity of air (62 pounds per cubic foot lifting capacity for water and .0755 pounds per cubic foot lifting capacity for air).

            Air is a dilute lifting fluid that only lifts a small fraction as much as does water, however, everything that works in air works equally as well in water which is merely a more dense lifting fluid or visa versa.  Therefore, we can simulate the fluid dynamics that will apply to the gravityplane in air with the scale model sea glider in water.  Like the gravityplane, the scale model sea glider will be able to harness gravity and will be able to continuously glide both upward and downward through the water without the use of fossil fuels or the need for battery power.

            The major difference in Hunt Aviation’s patent pending technology is that conventional sea gliders require battery power in order to operate and our fuel-less sea glider harnesses power from the kinetic energy of motion of the sea glider through the water via an underwater hydro-turbine or a surface wind turbine, just as the gravityplane harnesses power from the kinetic energy motion of the air using its wind turbines and kinetic energy of motion of the water via hydro-turbines.

            The wind turbine or hydro-tubine is formed by attaching a rotating horizontal disk to a vertical axis shaft that is mounted to a frame on bearings, which allows the disk and shaft to rotate.  Shutters are made into the disk that can open perpendicular to the horizontal disk or can close to a position parallel to and even to the surface of the disk.  On one side of the turbine, two shutters open with one opening upward and one opening downward to form a " V" shape in order to catch the wind or water and then move backward with the wind or water due to the force applied on the shutters that rotates the disk and vertical shaft.  On the opposite side of the wind turbine the shutters close down into the disk in order to go into the wind or water with minimal drag - about the same drag as a discus thrown through the air or an aileron of an airplane.  In comparison a conventional horizontal axis wind turbine or hydro-propeller creates drag across the entire area of the circumference of its vertical blades that are directed into the flow of the wind or water.

            Current sea glider models have a velocity of only .5 knots, which is too slow to generate much power using a hydro-turbine due the small amount of motion though the water.  Hunt's sea glider will dive and submerge much more forcefully and will therefore be able to generate and store a lot of power and will; therefore, travel from point-to-point a lot faster with an unlimited range.

            The science that will be proven in water by the sea glider scale model of the gravityplane will help to engineer the aircraft.  Conventional sea gliders glide in both the upward and downward direction in water and this proves that the gravityplane can also glide in both the upward and downward directions through air.

            This also means that the gravityplane will be able to glide and generate power while climbing to altitude using aerostatic lift.  The sea glider scale model will prove that flight in air and underwater transport can be accomplished by the use of gravity power to produce and store power via harnessing the kinetic energy of motion with a wind turbine or hydro-turbine.

            However, the sea glider and gravityplane do not have to solely depend on the power of gravity (which is the science of harnessing mass differentials to cause buoyancy and gravity acceleration in an alternating cycle of going from heavier-than-water or air to being lighter-than-water or air) for operation as the craft will also innovatively harness other environmental power sources, such as solar power, wind power, water current and wave power, pressure differentials, temperature differentials, current differentials within wind or water, etc. that are available energy sources provided by nature.

            Hopefully, during this year to prove the new hybrid craft’s ability to work in either the air or water, Hunt Aviation plans to lift the sea glider model of the gravityplane to high altitude using helium balloons and release it to accomplish fuelless flight. Robert Hunt, as a private pilot and sailplane enthusiast, plans to fly the glider. Power will be produced and stored in the form of compressed air by the wind turbine as the craft glides downward toward the earth. The compressed air will run a generator to generate electrical power to demonstrate that power was actually stored as hundreds of miles of distance was quickly traveled – proving the underlying concept of fuel-less flight I will fly a substantial distance and then will bring back to earth stored energy without burning one drop of fuel whatsoever.

Flight Can Be Sustained Using The Forces Of Gravity

           Many people do not realize that buoyancy is a property of gravity.  Gravity exerts a greater pull on more dense materials than on less dense materials, which causes buoyancy.   A bubble rises in water and helium rises in air because they are less dense than the surrounding lifting fluid.

            Gravity acceleration, which is commonly thought of simply as the downward gravitational pull of the earth, is the reason a glider is able to fly (See a more detailed explanation of gliding under the heading A Glider Flies via Gravity Acceleration).  When you combine the two forces of gravity (buoyancy that is an upward pull and gravity acceleration that is a downward pull) into a new hybrid aircraft, it can rise into the sky via aerostatic lift, using a lifting gas such as helium or by the lifting force of a vacuum, and then glide downward like a glider using the gravitation pull of the earth.  Before being able to glide, however, the aircraft must first change from being lighter-than-air to being heavier-than-air.  This weight change may be accomplished by bringing compressed air from the surrounding atmosphere into the aircraft to make the aircraft heavier to lose lift.

            The Compression of atmospheric air into the aircraft requires an energy input.  The required energy may be generated by a wind turbine from the high velocity wind created while gliding downward and energy may be stored in the form of compressed air that is stored in high pressure storage cylinders.  The stored energy may be used later to change the weight of the aircraft by powering pneumatic motor driven compressors to compress air that is taken from the surrounding environment into the aircraft to add mass to the aircraft.  Importantly, however, the weight of the stored compressed air must be conserved aboard the aircraft after it has been expanded in order to obtain power to drive the pneumatic motors (See a detailed description of how this process is accomplished under the heading Ballast Process).

            During descent, the compressed air also beneficially adds weight to the aircraft.  The aircraft glides faster as it becomes heavier; however, the glide slope remains the same because increased velocity causes the air to flow faster over the wings, which provides more aerodynamic lift to offset the additional weight.

            The amount of energy produced by the wind turbine while gliding down is directly related to the height (potential energy) at which the glide begins, with the higher the altitude of the starting point the greater the length of time that the aircraft glides downward and produces power.  A portion may be stored for later use.  Gravity is used to lift the aircraft via buoyancy and also is used to generate power via the wind turbine as it glides downward, as well as provide forward momentum while gliding.

            Height represents potential energy and height provides the power needed for the new hybrid aircraft to glide and to produce and store power.   The higher the aircraft is the more potential energy it has that can be converted to kinetic energy of motion, and; therefore, the greater distance it can glide and the more power it can generate and store.

            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.

            Hunt’s invention is an open system using these two well known forces of gravity provided by our natural environment. The gravity technology is equivalent to harnessing the power of the wind or harnessing the power of sunlight that are provided by nature, only in this case the power of nature that is being harnessed is the power of gravity, which is also responsible for buoyancy due to the greater gravitation pull of the earth on the surrounding air than on the less dense lifting gas or a vacuum.

            One force of gravity can take you up and the other can take you down.  Understanding the potential of this dual relationship and creating a cycle out of the up and down motion is the heart of Hunt's new gravity powered technology, that will make our world a better place to live and a cleaner environment for our children and their children.

            The new hybrid gravity-powered aircraft is formed by merging the capabilities of the following devices into a single new aircraft apparatus:  (1) an aircraft capable of aerostatic (lighter-than-air) lift to gain altitude; and, (2) a glider aircraft capable of aerodynamic lift, having a high glide ratio to accomplish long range gliding; and, (3) a wind turbine that is capable of harnessing the force of wind to generate power and to store power as the aircraft glides downward.

A Glider Flies Via Gravity Acceleration

            A conventional glider is towed to fairly high altitude by an airplane or is launched by a tow wench.  Potential energy is created as the glider gains altitude.  As the glider dives toward the earth, the aircraft trades the potential energy difference from a higher altitude to a lower altitude to produce kinetic energy. The glider picks up speed as it falls due to gravity acceleration, which causes high velocity wind to pass over the wings of the glider to create aerodynamic lift.  Gliders can climb upward while diving downward by catching rising air currents known as thermals in which the air is rising faster than the glider dives downward to achieve an overall upward rise.  A glider is capable of gliding much further than an airplane because it has greater aerodynamic lift due to long narrow, high aspect ratio wings.  A glider is able to fly because it is able to harnesses a force of gravity -- gravity acceleration.

The Principal Of Buoyancy In Air

            Lighter-than-air (aerostatic) lift may be explained by the principal of buoyancy, also known as the Archimedes Principal which states: an object immersed in a fluid experiences a buoyant force that is equal in magnitude to the force of gravity on the displaced fluid.  Stated differently, the lifting capability is equal to the weight of the surrounding fluid mass that it displaces.  Displacing a cubic foot of air creates a lifting capacity equal to the weight of a cubic foot of air, which is .0755 pounds per cubic foot.

            The lifting capability of helium in air is .062828 pounds per cubic foot at sea level.  Hydrogen has a greater lifting capability in air than helium and can lift .0724 pounds per cubic foot at sea level.  However, the lifting capability of a vacuum (the absence of any gas molecules at all) beats them both at .0755 pounds per cubic foot at sea level, which is equal to the weight of a cubic foot of air.  The reason the lifting capacity of hydrogen or helium is less than the lifting capacity of a vacuum is that the weight of the helium or hydrogen must be subtracted from the lifting capacity in order to obtain a net lifting capacity.  Helium is heavier than hydrogen and the lighter hydrogen, therefore, has a greater lifting capacity than does helium.

            A conventional aerostatic airship creates lift by the use of gases that are lighter-than-air, such as helium, or use hot air which is less dense than cold air for lift.  The lift capacity of hot air is much less than the lift capacity of a lifting gas.  Hydrogen generally is not used as a lifting gas any longer because it is explosive and combustible.  Lighter-than-air airships are now being designed to attain altitudes of over 100,000 feet and may be built very large to carry heavy loads of passengers and cargo approaching 1,000 tons.  By comparison, a U. S. military C-17 heavy lifter only carries near 70 tons.

            A vacuum contained within an enclosure creates aerostatic lift as it displaces the surrounding air and creates buoyancy.  Vacuum-lift may alternatively be used instead of a lifting gas by Hunt's new hybrid aircraft to provide lift.  The aircraft is formed by connecting a series of cells that are strong enough to hold a vacuum and light enough to be lifted by the vacuum formed within the cells.  Helium only lifts eighty percent (80%) as much as a vacuum lifts.  Lifting gases stop lifting at very high altitudes when the density of the surrounding air is equal to the density of the lifting gas, known as pressure height.  However, a vacuum can lift as long as there is any surrounding air to act as a lifting fluid, which would allow a vacuum lifted aircraft to go to a higher altitude and it can become heavier than air merely by allowing a portion of the vacuum to be replaced with surrounding air by opening an air passage to the cells.  The vacuum would then be regenerated using wind turbine power during the descent after heavy compressed air is brought into the aircraft to increase its weight so that it remains heavier-than-air.

            As a safety feature, the new hybrid aircraft will use a dual-aerostatic-lift system that will include the use of vacuum-lift and the use of a lifting gas.  The lifting gas serves as a backup system in the event of failure of the vacuum-lift.  The vacuum is contained within rigid cells that make up the aircraft and the lifting gas is expanded into collapsible gas bags within the cells in the event of rupture of the walls of the cell.  During normal operation of the aircraft, the gas bags remain collapsed and lift is provided by the vacuum held within the cells.

            Alternately, if a pure vacuum cannot be achieved due to material constraints, a partial vacuum may be formed to allow a lifting gas to achieve more lift by being allowed to expand to extremely low pressure, such as less than five pounds per square inch of pressure.  The initial aircraft will probably use a partial vacuum on the inside of the cells within the aircraft that will form low pressure on the outside of the gas bags that hold expanded helium lifting gas within the gas bags at extremely low pressure.  The effect is equal to the gas bags being at high altitude while they are at low altitude and more lift is achieved at low altitude by the process.  As altitude is increased, the pressure differential decreases, instead of increases as it does in a conventional airship, as the atmospheric pressure drops.

The Effect Of Gravity As A Relationship Between Densities Of Bodies Of Mass

            The greater the density of a body of mass, the greater the gravitational pull of the earth on that body of mass.  Gravity causes high density mass to sink within lower density mass, like a piece of high density steel sinks in lower density water or like higher density water droplets fall downward toward the earth in lower density air, as each is heavier (higher density) than their respective surrounding body of mass.

            The interesting thing about this process is that the gravitational force can cause motion in both the upward and downward directions.  Place a helium balloon in the air and the balloon rises because it contains a lower density gas (helium) than the density of the air surrounding the balloon.  Likewise, an air bubble in water has a lower density than the density of the surrounding water, which causes the bubble to be lifted upward by the surrounding lifting fluid - water.

            Hunt Aviation’s new aircraft has the capability to alter its density (mass as a unit of weight per cubic area) in relationship to the mass of the surrounding air by the use of collapsible gas bags that are inside of the aircraft into which low pressure, low density helium is expanded, which causes the overall density of the aircraft to be lighter-than-air, or by forming a vacuum within the cells to create vacuum lift to become lighter-than-air.

            To make the overall density of the airship heavier-than-air to become a glider, compressed air contained in high pressure cylinders is used as a power source to operate pneumatic motors that drive air compressors to bring in compressed air from the surrounding atmosphere to add weight to the aircraft.  The new incoming compressed air from the atmosphere and the expanded compressed air from the cylinders are allowed to enter into the area between the inside of the cells of the aircraft and the outside of the gas bags holding the low pressure helium.  The helium is compressed due to the greater pressure of the compressed air outside of the gas bags and as the helium is compressed its volume decreases until it occupies far less area in which the helium occupied while expanded in the gas bags.  High weight compressed air replaces the space in which the expanded low density helium within the gas bags had previously occupied.  The total mass of helium remains constant, but the volume in which the mass is housed is dramatically reduced as a result of compression of the helium and in the process additional weight is added to the aircraft in the form of compressed air in order to lose lift.  In the event a pure vacuum is used within the cells for lift, air from the atmosphere may be allowed to enter the cells in order to release the vacuum and to add mass to aircraft to lose lift.

Potential Energy Gained By Altitude Determines The Range, Duration Of Flight And The Amount Of Stored Power That May Be Generated By The Aircraft

            The height that is attained determines the amount of potential energy available that may be converted to kinetic energy as the hybrid aircraft glides downward.  As the aircraft rises it gains potential energy.  The higher the altitude gained by the aircraft; the greater the amount of potential energy that is created that may be converted to kinetic energy of motion as the aircraft glides downward from high elevation.  The amount of energy that may be generated by the wind turbine via gravity acceleration is in direct relationship to the height (amount of potential energy attained).  The higher the aircraft is before it starts gliding the longer the duration of time and the further distance it will glide downward producing power.  The aircraft trades the potential energy difference from a higher altitude to a lower altitude to produce kinetic energy as it glides downward.

For example, let's assume that the glide begins at 1,000 feet and the aircraft begins to pick up speed by gravity acceleration (9.8 meters per second, the speed of gravity acceleration) and much of the low altitude is traded for velocity to reach glide speed and as a result the glider doesnt go very far.  The amount of energy gained via converting the potential energy of 1,000 feet of height to kinetic energy of motion by the aircraft is too small to be very useful and the wind turbine of the aircraft would not have generated nearly enough energy to compress the required amount of air into the aircraft to lose lift on the next flight.

            Now let’s assume that the aircraft takes a second flight and starts its glide from an altitude of 52,800 feet (10 miles high). It accelerates to the full glide speed via gravity acceleration within the first thousand feet then glides downward at constant speed for over two hours at 200 miles per hour with a 40 to 1 glide slope or 40 miles forward to 1 mile down (10 miles down times 40 miles forward = 400 miles traveled divided by 200 miles per hour = 2 hours of flight). During the glide the aircraft stores compressed air produced by the wind turbine as stored energy and within less than thirty minutes from the time the glide began, it had stored enough energy in the form of compressed air to power a pneumatic motor to drive an air compressor to compress the required amount of air into the aircraft to lose lift on the next climb-out to high elevation. Compressed air can be used for propulsion, electrical power generation, or used to perform any other form of mechanical work.

            From this illustration comparing two different altitudes at which the glide starts, it can readily be seen that the amount of potential energy gained that may be converted to kinetic energy of motion is in direct relationship to the height attained.  The energy input to compress air into the aircraft to lose lift is relatively constant, but the energy output via harnessing gravity by creating potential energy that is immediately converted to kinetic energy of motion changes dramatically by the altitude gained before the glide begins.

            If sufficient altitude is not gained before the glide begins, then there is not enough energy produced and stored as compressed air to perform compression of air into the aircraft to lose lift during the next flight to high altitude and the craft must land and replenish its supply of compressed air, which is its fuel source, before starting another flight.

            By starting the glide from great elevation and employing aerodynamic designs having high glides slopes, the duration of power generation may be on the order of many hours at a time before the requirement to again alter its mass in relationship to the surrounding air occurs.  Thus, power produced by the wind turbine and stored during these long glides will be available to meet the energy needs of the aircraft for air compression and for other energy requirements.

            The heavier the aircraft; the faster it is capable of gliding downward as the gravitational pull is greater. The aircraft can become much heavier by storing large quantities of highly compressed, heavy air in order to glide faster. Thus two beneficial purposes are served by the compression and storage of air by the wind turbine: (1) energy is stored for later use; and, (2) the aircraft becomes heavier and glides downward faster. The aircraft would normally land with a significant load of compressed air – its fuel for later use, including thrust for vertical take-off.

The Importance Of The Use Of Wind Turbines On The New Aircraft

            The new aircraft is able to continue to fly for extended periods of time because of the use of wind turbines.  Critical processes that must be accomplished to create the gravity powered flight cycle, such as compression of air into the aircraft to lose lift, need energy input.  Wind turbines produce and store energy in the form of compressed air as the aircraft glides downward via gravity acceleration.  The stored energy is later used by the aircraft after it rises to substantial height and again needs energy to compress new air into the aircraft to lose lift.  The aircraft lands with a cargo of compressed air made possible by the use of wind turbines to produce and store compressed air, which serves as the source of energy that is used for air compression to increase the weight of the aircraft to lose lift during the next flight.

            The wind turbines can generate power while the aircraft is on the ground, tethered above the ground, or floating on water so long as the wind blows with sufficient velocity and provided the wind turbines are faced into the wind. This allows the supply of compressed air to be fully charged after use for short flights that do not produce sufficient compressed air to resume high altitude flight and provides compressed air produced by the wind turbines to drive pneumatic motors to run generators to produce electrical power while on the ground or floating in water.

New Vertical Axis Wind Turbine

           Robert Hunt is the inventor of a patent pending vertical axis wind turbine that is ideally suited for use by the new hybrid gravity powered aircraft. The wind turbine uses drag as the operating force. It alternates from an extremely high drag configuration to an extremely low drag configuration to more efficiently harness the power of the wind. This is accomplished by shutters that close to form a large sail area when pushed by the wind to create high drag to harness the power of the wind and then open to a very narrow surface area to cause low drag when rotating into the wind.


Unique Design Features Of The Craft

            The wings of the craft are capable of being rotated along a ninety degree arc.  This allows the sweep of the wings to be altered as needed.  The high aspect ratio wings are fully extended for take-off and landing and for slow speed gliding to achieve high lift.  The wings may be swept back to accommodate high speed flight, especially during high velocity dives from high altitude.

            The ship is equipped with three reversible turbines that can serve either as wind turbines to generate energy during descent or be used as propulsion turbines to power the ship. The smaller turbines mounted on each side of the craft may also be used to provide steering assistance. The turbines are connected to pneumatic motors / compressors. As wind rotates the turbine’s blades that are connected to a compressor by a common shaft, the turbine drives the compressor and atmospheric air is taken into the compressor to be compressed and may be stored for later use. When the stored high pressure compressed air is run back through the compressor to rotate the compressor, the compressor becomes a pneumatic motor that drives rotation of the turbine to produce jet propulsion. The turbine can produce and store power generated from the kinetic energy of motion of wind or in the reverse mode of operation use the power produced by the wind to provide jet propulsion.

            The aircraft is designed to carry heavy loads of passengers and cargo without combustion of hydrocarbons as fuel, can stop and hover in place weightless at any time, and can takeoff and land vertically, using compressed air as its fuel that it produces itself during flight via gravity acceleration.

            The aircraft can land on any open, relatively level spot of land and does not necessarily need an airport.  Any sizable body of water provides an excellent landing site and it can also be used as a boat after landing on water.  The pontoons of the craft are filled with helium to provide lift in air, but likewise they can provide lift within water.

How To Build The New Hybrid Aircraft

            Start by using advanced new strong, lightweight materials that are now available, such as carbon fiber or Kevlar bonded with epoxy resin to construct a rigid frame and outer skin.   Additionally, lightweight non-porous Mylar will be used to form the balloon type gas-bags to hold the helium gases, which can escape more porous materials.  Engineering performed by material science engineers for Hunt Aviation indicates that a rigid outer shell with gas bags inside the shell using these new ultra-lightweight materials may readily be built that will be capable of being lighter-than-air when the gas bags are filled with helium.

            A single layer of Kevlar covering an area of a square yard that is bonded with epoxy resin may weigh as little as three ounces.   The use of multiple layers of composite material and adding the weight of a carbon fiber framework is estimated to create a total weight of less than 16 ounces (one pound) per square yard of surface area to build a lightweight rigid aircraft. 

            The larger the cubic area that is enclosed the less the number of square feet of surface area that there is in ratio to the number of cubic feet of lifting-gas capacity within the enclosure.   A cubic enclosure that has six identical sides that are 6 feet by 6 feet, has an internal area of 216 cubic feet and has 216 feet of surface area or a 1 to 1 ratio of surface area to cubic feet of lifting gas area.  If the size of the cubic enclosure is increased to10 feet by 10 feet per side, there are 1,000 cubic feet inside the cube and the sides of the cube have 600 square feet of surface area, increasing the ratio to 1.6.  The greater the size of the cube the better the ratio of lifting gas area to square feet of surface area. 

            This ratio helps to determines at what size the craft can become lighter-than-air when filled with helium.  If the total weight to be lifted is 16 ounces per square yard of surface area, then we must have a ratio that will provide sufficient lift.  The lifting capability of helium in air is .062828 pounds per cubic foot at sea level.  A ratio of two means that there are two cubic feet of lifting gas area for each square foot of surface area or .1256 pounds of lift per square foot of surface area or 1.13 pounds per square yard, which is over 18 ounces of lift capacity per square yard of surface material, which is greater than the 16 ounces of lift needed to make the aircraft lighter-than-air.

            The size of a cube needed to get a ratio of 2 is only 12 feet by 12 feet sides.  A cube having 18 feet sides provides a ratio of 3 and a cube having 30 feet sides has a ratio of 5.  It is easy to see that a reasonably sized rigid enclosure may be constructed that can become lighter-than-air to gain altitude using helium as the lifting gases.

            To build an aircraft that is made lighter-than-air by use of a vacuum that provides greater lift than a lifting gas will require the use of composite materials that are strong enough to hold the negative pressure of a vacuum within the sealed cells and are light enough to be lifted by the lifting effect of the vacuum therein formed.  A vacuum would be more advantageous than the use of a lifting gas because hydrogen and helium consist of small molecules that are difficult to retain within a closed space, which is why helium balloons lose their inflation after a few days.  Hydrogen gas is both flammable and explosive, making it a dangerous substance to use.  Helium, while it is inert, is rare and costly, and it is expensive to constantly replace lost helium due to the inability to adequately retain its tiny molecules.

            The aircraft is made up of a cellular matrix.  The wings and fuselage are composed of a series of rigid cells; within each cell is a flexible gas bag capable of holding helium to provide lift and each cell is capable of holding a vacuum or partial vacuum.  Compressed air can be individually supplied to each cell on the outside of the gas bag to add weight when it is desirable to become heavier-than-air.  The lifting capacity of the aircraft must be sufficient to carry an adequate supply of compressed air within high pressure storage containers during its climb to high elevation in order to compress a portion of the helium within the cells to lose lift.

Power Of The Wind

            A wind turbine is capable of generating power from the kinetic energy of motion of the wind.  The power of wind is cubed.  If the velocity of the wind increases from ten feet per second to twenty feet per second, the kinetic energy in the wind is not doubled, but rather it is eight times greater (2 X 2 X 2 = 8).  And if the velocity is then increased to forty feet per second the power of the wind is not four times the original ten feet per second but is sixty-four times greater (8 X 8 = 64).  From this illustration you can see why hurricane and tornado force winds destroy buildings, because the power of the wind grows exponentially with increased velocity.  The new gravity powered aircraft will have wind velocities into the hundreds of miles per hour striking its wind turbines as it rapidly descends from great heights by gravity acceleration and a very large quantity of energy may be generated by the wind turbines for extended periods of time as individual glides may last for several hours.

Safety Considerations And Air Travel Concerns

            Due to the aircraft’s ability to alter its lift via aerostatic lift at any time, it is capable of floating in the air whenever it is desirable to do so. This natural floating capability prevents “falling out of the sky” as conventional airplanes do when jet engine power is lost, which vastly increases the safety of Hunt Aviation’s hybrid aircraft..

            Fuel-less flight also brings a far greater degree of safety because there is no jet fuel to spill and burn.  The combustion of aircraft fuel is the major cause of loss of life in the crash of a conventional airplane.

            After 9/11 many people are very concerned over air travel, fearing that airplanes filled with explosive aviation fuel may become lethal weapons.  This has greatly reduced air travel and tourism.  The new hybrid aircraft does not carry explosive fuel and it is believed that passengers will feel much safer flying in an aircraft that has no explosive or combustible fuel.

Cost And Weight Of Aviation Fuel

            The rising cost of aviation fuel is the greatest, uncontrollable expense that airlines face. It is obvious that the “innovation of fuel-less flight” is a major achievement in aviation, but it is also a major economic accomplishment. Also, liquid aviation fuel is very heavy, which is an advantage that Hunt’s aircraft does not have to carry a substantial load of fuel into the sky.

Positive Environmental Impact Of The Wind-Powered Airship

            There are no emissions from the aircraft to create greenhouse gases that can cause global warming as is produced by convention aircraft using combustion jet turbines, nor does the airship harm the ozone layer as is done by conventional supersonic flight.  The environment will be greatly enhanced and protected by the invention of this aircraft that accomplishes flight via harnessing the gravitational pull of the earth to provide a silent gliding style of flight that does not generate loud sounds, as do jet engine powered aircraft.

Advantages Of The New Hybrid Aircraft

            The major advantages of the gravityplane are:

  • does not require fuel, which accounts for over eighty percent (80%) of the operating cost of conventional air travel; and,
  • does not have to lift the weight of fuel during take-off or flight; and,
  • makes energy instead of using energy via harnessing gravity by use of the wind turbine; and,
  • has the capability to take-off and landing vertically, which is a significant advantage over conventional airplanes; and
  • can deliver people and products directly to the destination; and,
  • does not necessarily need an airport; and,
  • has very heavy lifting capabilities on the order of a ship when built to very large size; and,
  • is safer because there is no fuel to explode and burn; and,
  • is safer because it can gain neutral buoyancy at any time and float in the air, which can prevent a crash landing; and,
  • is safer because of use of a dual-aerostatic-lift system that will include the use of vacuum-lift and the use of a lifting gas as a safety feature; and,
  • is safer because it is less likely to encounter terrorist activities because there is no fuel to make it a flying bomb; and,
  • is environmentally friendly because there are no greenhouse gas emissions; and,
  • is environmentally friendly because there is not harm the ozone layer; and,
  • is environmentally friendly because there is no noise pollution; and,
  • potentially can fly within the stratosphere where the air is thinner so there is less resistance.

  • Synopsis Of How The New Aircraft Technology Works (Patents Pending):

               (1) Lighter-Than-Air Lift – inert helium gas fills gas-bags enclosed within the rigid shell of a lightweight composite aircraft in order to gain substantial altitude via aerostatic lift; and,

                (2) Loss of Lift – compressed air is pumped into the aircraft to make it heavier to lose lift, so that the aircraft becomes heavier-than-air to become a glider; and,

                (3) Gliding – the aircraft glides at a high glide slope for long distances via gravity acceleration, like a conventional glider, at speeds in excess of two hundred miles per hour;

                (4) Wind Turbines – create and store energy in the form of compressed air, using the force of the high speed flow of wind to generate power as the aircraft glides downward. The high speed wind that powers the wind turbines is created by gravity acceleration of the aircraft

                (5) Start Over – The process begins again by discharging the weight of the stored compressed air to lose weight and to power propulsion to again make the aircraft lighter-than-air via aerostatic lift to gain altitude to continue the flight process.

                (6) Stored Energy for Compression – energy stored in the form of high pressure compressed air stored in high pressure storage cylinders via power generated by the wind turbine is used to power pneumatic motors that drive air compressors to compress air from the atmosphere into the aircraft to make it heavier-than-air to again lose lift to become a glider in a cycle. (Note: The high pressure compressed air that is expanded to power the air compressors is retained on the aircraft to conserve the weight of the expanded air.)

    Description Of The Test Pontoon Lifting Body

                Prototype composite components for Hunt Aviation’s aircraft will be constructed at United States Marine, Inc. Engineering is being finalized for a prototype lifting body to be constructed within the next few months. The lifting body is a pontoon shaped cylinder having a diameter of twenty feet and being one hundred feet in length. The cylinder contains 31,400 cubic feet of area that is capable of holding a lifting gas. The cylinder contains 6,405.6 square feet of surface area. The ratio is 4.9 cubic feet of lifting gas holding area for each square feet of surface area (31,400 cubic feet divided by 6,405.6 square feet = ratio of 4.9).

                The lightweight composite material from which the pontoon is constructed will weigh 16 ounces (one pound) per square yard.  This level of weight allows the cylinder to be constructed using four individual layers of lightweight composite materials, including a carbon fiber corrugated frame made of corrugated sections, with a first layer of carbon fiber tape wound around the ring segments to tie them together securely, then one layer of Kevlar running longitudinally the entire length of the cylinder and a second layer of Kevlar tape spiral wound around the cylinder to tie the entire series of layers together then the carbon fiber and Kevlar fabric are bonded together with epoxy resin to the carbon fiber corrugated frame.  Each of the two Kevlar layers has a weight of 3 ounces per square yard and the carbon fiber corrugated frame layer weighs 5 ounces per square yard and the spiral would layer of carbon fiber has a weight of 5 ounces per square yard for a combined weight of 16 ounces (one pound) per square yard or 1.77 ounces per square foot.   The radial corrugated design pattern of the carbon fiber will provide substantial additional strength to the cylinder.  The total weight of the pontoons 100 feet by 20 feet diameter rigid shell is 712 pounds.  Helium has a lifting capacity at sea level of .062828 pounds per cubic foot.  The 31,400 cubic feet of area when filled with helium can lift 1,972 pounds at sea level, providing a gross lifting capacity of 1,260 pounds less the weight of the polyester reinforced nylon collapsible gas bags and cell dividers having a weight of 3 ounces per square yard with an area of approximately 7,285 square feet is 152 pounds.  The total weight of the pontoon with the gas bags is 864 pounds and the net lift of the pontoon is 1,108 pounds.

                More lift can be obtained by pulling a partial vacuum in the annular space between the gas bags and the inside walls of the cells to cause the pressure on the outside of the helium gas to be lowered to cause the helium to further expand within the gas bags in order to lower the density of the helium by reducing its pressure below atmospheric pressure and thus increasing its lift capacity as the helium further expands.  The removal of air from the cells while forming the partial vacuum removes weight from the cells as well.

                Cells will be created every 20 feet along the cylinder that are formed using flexible walls made of strong lightweight nylon that is polyester film reinforced that will act as dividers to create the individual cells.  New lightweight reinforced films that are used to build pressurized balloons can withstand up to 45 pounds per square inch of pressure.  An individual gas bag capable of housing a low density lifting gas will be within each of the five cells.  This matrix of cells with internal gas bags will provide pressure and lift control for the pontoon.  The gas bags can be filled with low pressure, low density helium to provide lift.  Compressed air having a higher pressure than the pressure of the helium can be provided to the annular space between the gas bags and the inside walls of the cells to add weight and to provide compression to the helium gas bags to cause them to shrink, causing a reduction in lift as the helium is partially compressed, which causes it to occupy a smaller area.  The heavy compressed air replaces the space that was previously occupied by low density helium.

                A mold is only needed to form the corrugated rings segments that provide the framework for the cylinder.  The strong carbon fiber rings are fabricated and are then mounted vertically on at least two horizontal pipes that are on the inside of the rings.  The pipes are suspended above ground level by vertical pipe sections that are fluidly connected to the horizontal pipes.  These pipes which are made of spiral wound lightweight Kevlar material remain inside the pontoon and provide the lines to control pressure control over the pontoons, supplying compressed air to the individual cells or removing air from the cells via a vacuum pump attached to the lines.  The vertical pipes are merely cut free from the ground attachments and are provided with fittings after the pontoon is finished.  The lines can be used as pressure vessels to hold supplies of compressed air as well being able to withstand pressure over1,000 p.s.i.  Spherical ends are added to the pontoon as the final procedure to allow access into the interior of the pontoon through the ends until near completion.

                A layer of carbon fiber tape is spiral would over the carbon fiber rings that makeup the framework to securely tie the corrugated ring frame segments together.  A layer of Kevlar material is applied horizontally to extend the entire length of the pontoon.  The layer is woven together with a second layer of Kevlar tape that is spiral wound around the circumference of the pontoon.  These three layers are bonded together and are bonded to the corrugated carbon fiber frame with epoxy resin once in place to make a strong lightweight cylinder capable of holding approximately 14.7 p.s.i of internal or external pressure, which is sufficient to allow a pure vacuum to be formed within the cylinder.

                Initial engineering analysis of the rigid composite materials construction technique described above indicates that the strong lightweight composite materials should be able to withstand internal and external pressures far in excess of that needed to form a pure vacuum.

                The lift capacity of this pontoon in regard to altitude attainable would be on the order of 20,000 feet of elevation above sea level before equilibrium known as pressure height is reached.  The density of the air at 20,000 feet is .0408, less the weight of the helium .011 pounds per cubic foot.  The net lift capacity of helium at this altitude is .0298 times 31,400 cubic feet of helium gas equals 935 pounds of lift which is greater than the 864 pounds of weight of the prototype pontoon.  Temperature and humidity and other factors also affect this calculation.  It is only an approximation used for illustration purposes of estimated potential height obtainable by the small prototype pontoon.  Larger pontoons will have greater capabilities in regards to obtainable altitude.  The prototype pontoon will be tethered to the ground, so this calculation is not critical to its development, but it is important to know the potential altitude attainable for later models that will actually fly as height represents potential energy that may be converted to kinetic energy of motion. 

Testing Of The Pontoon

            The pontoon will be tested for mass / volume relationships to determine precise control methods.  The following describes tests procedures anticipated at this time:

            Fabricate the pontoon lifting body having five individual cells with a collapsible gas bag capable of holding helium gas being within each cell.  The pontoon is connected to tether lines attached to the ground.

            Fill the gas bags partially full of helium gas and with draw air from between helium bags and interior of pontoon within cells.

            Measure the maximum amount of net lift of the pontoon via an accurate scale in regards to the upward pull of the pontoon on its tether lines.  The maximum lift will be obtained by the use of a partial vacuum outside the gas bags allowing the helium in the bags to expand without opposition from atmospheric pressure at sea level and removing gas molecules that have weight from the pontoon between the gas bags and the shell of the pontoon, which results in very low pressure, low density helium that has a pressure that is substantially below 14.7 p.s.i. being within the gas bags in order to provide greater lift.

            Cause the pontoon to sink on one end by providing compressed air to the end cell on the end that will sink.  Then, sink the opposite end by the same method.  Basically, cause the pontoon to rock back and forth by alternately sinking one end then sinking the opposite end.  During this time the center of the pontoon still provides its full lifting capacity via the three center cells that are isolated from the two end cells, of which the mass / volume relationship is manipulated to cause the back and forth rocking motion of the pontoon.

            The rising end provides thrust via jet propulsion to assist in rising.  A jet shaped exhaust port that is aimed downward ejects the compressed air, which has substantial weight, to produce upward thrust and to reduce weight by discharging the heavy compressed air.

            Air to perform these functions will be obtained from a tank of compressed air that is on the ground.  The action will be rapid; much like an inflatable air bag in a car that is almost instantly inflated by a supply of compressed air from a container.  Loss of lift will occur because the very low pressure helium gas within the gas bags will undergo compression as higher pressure compressed air is supplied on the outside of the bag and the pressure builds between the gas bag and the shell of the pontoon, compressing the helium in the gas bags and adding weight to the cell via the heavy compressed air.

            Tests conducted on the pontoon will provide us with empirical data that will allow the development of flight control systems to manipulate the mass / volume relationship.  Density is defined as the quantity of mass divided by the volume in which the mass is held.  Therefore, the density is altered to change the lift characteristics on a cell by cell basis to control the overall center of gravity of the aircraft.  This function will be operated by a computer program that will be developed as a result of the above described tests.

Development Of The First Manned But Tethered Aircraft

            A second pontoon will be constructed to match the original pontoon and wings and other aircraft flight control structures, such as ailerons and a rudder, will be added to the structure.  A wind turbine will also be installed and small thruster propulsion turbine will be installed.  The unit will be manned in flight, but will be tethered to the ground at very low altitude (probably less than 500 feet); therefore, minimal cabin area will be needed.  This craft will provide interesting data in regards to aerodynamic criteria as it will function much like a kite when the wind is blowing and thus will incorporate aspects of both aerodynamic lift and aerostatic lift.  Less aerostatic lift will be required to maintain flight configuration.

            In many ways this tethered device may be considered a flying wind turbine that employs both aerodynamic lift (like a kite) and aerostatic lift (like a helium balloon).  Power will be generated when the wind is blowing.  The power will be generated and stored as compressed air within high pressure pipes within the pontoons that act as pressure vessels.  A portion of the compressed air will drive a pneumatic motor that will power an electrical generator to provide on board power and to charge the crafts batteries.

            If sufficient heavy compressed air is allowed to be stored, then the lift will be reduced and the craft will lose altitude due to the increase in compressed air ballast weight.  However, the lift is created by two lift forces and the cargo of compressed air when the wind is blowing is greater than if aerostatic lift alone were used.  The craft can experience vertical landing by building up a supply of compressed air heavy enough to slowly sink it to the ground and using the propulsion turbines to assist the landing via downward thrust to slow the descent as the computer controls the lift ballast of the aircraft to keep it level.  Likewise, the craft can practice vertical take off by downward thrust that also reduces the weight of the craft as the air is exhausted through the propulsion turbines.     

            The compressed air will be used to provide steering of the craft into the wind.  Pitot tubes will sense the direction of the wind and then the propulsion turbines will provide thrust as needed to keep the craft headed into the wind so that the wind turbine continues to operate, aerodynamic lift is attained, and to keep the tether lines from becoming twisted due to excess rotation of the craft.  The winds velocity will determine the amount of aerodynamic lift generated and tests will be performed in varying wind velocities over a period of time to learn the proper procedures needed to maintain aircraft lift and stability under these changing conditions.  This data will provide the information needed to update and to complete the crafts computer control program.

The First Flight Of The Aircraft

            After satisfactory results have been obtained from operation of the tethered aircraft and after experimental class certification, it will be allowed to free-fly into the atmosphere.  The aircrafts initial gliding descent will be the first time that it will attain substantial velocity, perhaps the initial speed will be only be approximately one hundred miles per hour until more information is gained.  Engineering can predict what will occur, but those calculations will be substantiated with empirical data gained from actual flights.

            The area between the gas bags and the rigid shell will become a partial vacuum at sea level.  This causes the helium within the gas bags to react as if the helium was already at a higher altitude and allows the helium to be at extremely low pressure (substantially expanded providing more lift at sea level), while still on the ground due to the artificial low pressure inside the cells of the pontoon and on the outside of the gas bags.  This causes a differential of pressure at sea level as the pressure of the atmosphere (up to but less than 14.7 p.s.i.) applies a force against the rigid shell, being a partial vacuum within.  As the craft rises due to the discharge of ballast weight (compressed air) that also provides thrust via pneumatic motor driven turbine engines, the craft rises due to propulsion and due to a reduction in weight.  As it rises the amount atmospheric pressure on the hull actually decreases as the pressure of the atmosphere drops.

            At all times we will have control over the volume / mass relationship of the individual cells of the craft with the ability to alter the pressure within the cells on the outside of the gas bags, by increasing the pressure via compressed air or decreasing the pressure via a vacuum pump.   We do not plan to discharge any helium whatsoever.  If needed, a small portion of the helium will be compressed into high pressure cylinders for later use.  If the craft has risen to an altitude in which equilibrium has occurred, then it will not take much reduction in lift to start a descending glide downward resulting in an increase in the velocity of the wind.  Once falling the wind turbine will continue to compress air into the craft to increase the weight to keep it heavier-than-air and it will land heavier-than-air with a load of compressed air as ballast weight and as stored energy for propulsion.

            The aircraft may use rapid ascent (like a porpoise coming up out of the water into the air due to its kinetic energy of upward motion) and thrust via compressed air powered jet engine propulsion to intentionally overshoot the equilibrium altitude, which will cause it to fall back to the equilibrium altitude.  Upon starting to fall, a supply of compressed air may be pressurized into to the craft as it is returning to the equilibrium altitude to add weight to make it to continue the fall -- gliding forward and downward.  To exceed the anticipated target can be used beneficially in order to go into a diving mode by the loss of lift caused by exceeding the altitude of equilibrium by use of the kinetic energy of motion of the aircraft to provide power to bring additional weight into the aircraft in the form of heavy compressed air.  A dive created by loss of lift is necessary for the wind turbines to work and to initiate gliding.  Aerodynamic lift via the glider wings of the aircraft will alter the way it falls as opposed to a conventional aerostatic airship that is not designed to glide.  The structure of the aircraft will be able to support these conditions of course.

            Thrust can be powered in the same manner as air compression can be powered – by the stored power of compressed air held within high pressure compressed air storage tanks that is used to drive pneumatic motors to power a compressed air driven turbine. Like, in the use of air compression the weight of the air from the storage cylinders must be conserved on the aircraft by being expanded into the cells. If the weight of the air is lost, then the aircraft becomes lighter. The major advantage of powering thrust to gain additional altitude above the pressure height is that additional potential energy is gained in the process, which means that more energy is derived from the glide that begins at a higher altitude. Therefore, using thrust to overshoot the pressure height makes a more efficient method of operation as opposed to the use of air compression that may take longer and will not obtain additional beneficial altitude or forward motion.

Ballast Process

            The volume of mass within the pontoons or individual cells must change in order to change the weight of the pontoon.  The pontoons are sealed to the outside environment only!  Compressed air from the surrounding environment is supplied to the pontoons on the outside of the collapsible balloons containing low pressure helium, but on the inside of the cells within the rigid pontoons, increasing the pressure (causing compression of the helium within the balloons) and increasing the volume of mass (added weight in the form of compressed air) within the cells of the pontoons to make the entire pontoon heavier or individual cells heavier.  Likewise, air may be withdrawn from between the collapsible balloons and the inside of the rigid shell via a vacuum pump to decrease the pressure on the outside of the balloons and to remove mass (weight) from the cells to make them lighter.  Removed air is discharged to the environment when it is desirable to make the aircraft lighter and is compressed into high pressure cylinders when it is desirable to conserve the weight of the compressed air and to store power for later use.  Supply lines that perform these functions are connected to compressors that withdraw air from the environment surrounding the aircraft and are connected to the cells within the pontoons.   In order to create a vacuum within the cells, the suction side of the pneumatically powered or wind turbine powered compressor is switched to the cells.  The discharge side of the pneumatically powered or wind turbine powered compressor is switched to the cells in order to supply compressed air to the cells.  Therefore, the supply or withdrawal of air volume is mechanically controlled internally and the pontoons themselves are sealed to the environment.

            Air compressors powered by the wind turbines withdraw air from the environment while descending and store the compressed air within high pressure storage cylinders for later use to change ballast via stored energy.  The compressed air possesses stored power.  The energy within the compressed air powers pneumatic motors to drive air compressors.  The air compressors withdraw new air from the environment to add weight to the aircraft to make it heavier to start descending.  The stored compressed air within the high pressure cylinders is not discharged from the aircraft after driving the pneumatic motor but moves from the high pressure cylinders to a much lower pressure in the cells; therefore, the weight of the compressed air that was previously within high pressure cylinder storage is conserved (The physical volume of the compressed air changes, but the weight of the compressed air remains the same).

            However, new air mass (weight) is added via the incoming compressed air brought into the aircraft from the environment by the compressors that are powered via the pressure (high pressure compressed air within the storage cylinders that perhaps is as high as 1,500 p.s.i.) drop from higher pressure to lower pressure (low pressure within the cells that is higher than the pressure of the helium in the gas bags but far lower than the original pressure within the high pressure cylinders) to run the air compressors.

            When the aircraft is at pressure height and is merely floating in the air in equilibrium, only a relatively small volume of compressed air is required to be brought into the aircraft from the surrounding environment in order to initiate descent.  Once any velocity is obtained due to gravity acceleration, the wind turbines will begin to generate a powerful compression force to bring in additional air mass to add weight.   As the aircraft continues to descend and as it increases its velocity, the wind turbines begin generating more power and the process of bringing in additional air continues as the high pressure storage cylinders are refilled to replace air used in the previous processes, adding more weight to the aircraft. Additionally, using wind turbine power the helium within the gas bags may be compressed into high pressure helium storage cylinders and heavy compressed air can replace the area previously occupied by expanded helium to further reduce lift.

            Likewise, the power generated by the wind turbines may be used to form a vacuum on the outside of the gas bags within the pontoons to provide greater lift prior to landing.  The air withdrawn from the pontoons to form the vacuum can be compressed into the high pressure cylinders to conserve its weight aboard the aircraft.  Upon landing, the overall weight of the aircraft is much heavier than the surrounding air because of the large volume of high compressed air held as ballast weight on the aircraft.  The positive weight and glider shape of the aircraft makes it far more manageable during landing.  Vertical landing can be accomplished using compressed air to drive pneumatic motors to provide downward thrust.

Additional Considerations

            The aircraft could use vacuum lift alone, but the expanded helium in the gas bags serves as a safety feature, as rupture of a pontoon having only vacuum-lift could potentially cause catastrophic loss of lift.  The negative pressure on the aircraft actually decreases with height as it rises to pressure height.

            The aircraft has substantial flight control during vertical take-off via the propulsion engines and being heavier than air at that time with wings for aerodynamic lift as forward motion begins.

            It is important to realize that all of the compressed air is not discharged during take-off. A cargo of compressed air is carried all the way up to “pressure height” with the aircraft. The compressed air is the aircrafts supply of stored energy that is needed to change the aircraft to heavier-than-air at high altitude. Here is how the process works…

            The highly compressed air that may have a pressure within the high pressure compressed air storage cylinders on the order of 1,500 p.s.i. is used to power pneumatic motor driven compressors to bring in new compressed air from the surrounding environment into the aircraft to add mass to the aircraft to make it heavier-than-air.  The compressed air from the cylinders moves from the pneumatic motors to the cells within the pontoons to conserve its weight and to compresses the helium within the air bags.  Due to the compression of the helium, the compressed air (approx. 15 p.s.i.) within the pontoons now occupies a lot of the area that was previously occupied by lower pressure expanded helium.

            Alternately, the aircraft can use compressed air powered jet engine propulsion to climb above the pressure height to a point where the aircraft is heavier than air due to the thin atmosphere at that altitude.  The compressed air used to power the turbine moves to the cells within the pontoons to conserve its weight.  When the supply of stored compressed air is depleted, the aircraft begins a downward dive that provides kinetic energy via gravity acceleration sufficient to power the wind turbines that compress additional new air into the aircraft to make the aircraft heavier to continue the downward glide.

Generation Of Electrical Power During The Climb To Pressure Height

            Power can be generated on the climb to pressure height by the wind turbines as movement through the air as little as 20 miles per hour is sufficient to cause power to be generated. Upward gliding is possible as is proven by sea gliders that glide both in the upward and forward direction and the downward and forward direction (See Modeling the GravityPlane in water). A rate of climb of 5,280 feet (one mile) per minute would provide an upward velocity of three times that rate of nearly 60 miles per hour. The greater the effect of buoyancy the faster the upward glide speed and the greater the amount of power that can be generated by the upward gliding process.

Electrolysis Potential Via A Fuel Cell

            The upward velocity power generated could be stored as electrical energy or as chemical energy (hydrogen via electrolysis of water) to power a fuel cell to provide heat and to provide electrical power.  Water could be obtained from the atmosphere via compression.  As the air is compressed, the heat of compression is formed.  The higher pressure air is sent to an accumulator and begins to cool, which causes the water vapor to condense at the higher pressure and lower temperature, thus air compression typically generates a lot of water via the accumulator.

            Electrolysis via a reversible fuel cell could convert the water into hydrogen and oxygen, both of which are useful. The hydrogen may be used as both a lifting gas and as a fuel source for the fuel cell to generate electrical power or as a fuel for a hydrogen jet propulsion engine, etc. The oxygen may be used by passengers or for combustion purposes. To accomplish electrolysis a pneumatic motor drives a generator to produce an electrical current. The air from the pneumatic motor would then be discharged to the environment as not to add weight to the aircraft as it is climbing via lighter-than-air lift. The hydrogen could be housed within an expanded gas bag to additionally provide lift instead of helium, but that brings new risks associated with the volatile nature of the hydrogen. However, the technology of fuel cells using hydrogen is making it far safer. Some weight would be added to the craft by this process, but the weight would be minimal, especially if most of the oxygen is discharged. However, the oxygen may be needed to drive the fuel cell along with the hydrogen at high altitude. Fuel cells produce a lot of heat along with electrical power and water vapor when operating, all of which could be beneficially used by the aircraft.

            Unless it is absolutely necessary, Hunt Aviation does not plan to use a hydrogen powered fuel cell on prototype models of the GravityPlane. However, if needed a fuel cell could supply heat and electrical power that can be used to produce more heat via resistive heating.


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