Patent Application
20080184906
The subject matter of the invention is shown and described in the Disclosure Document of Joseph B. Kejha Ser. No. 569,743 filed on Feb. 7, 2005, and entitled “Long Range Hybrid Electric and Silent Electric Airplanes.”
1. Field of the Invention
This invention pertains to the construction of longer flight duration and longer flight range airplanes, on the same amount of any type of fuel; as compared to equivalent prior art airplanes. The airplanes of the invention also have a temporary silent flight capability in electric only mode of operation.
2. Description of the Prior Art
Prior art manned airplanes (MAVs) and unmanned airplanes (UAVs) of all sizes utilize powerful internal combustion internal combustion engines, which are necessary for take-off and climbing, but the same engines are oversized for cruising horsepower needs, and consume too much fuel, which shortens their flight range. Prior art airplanes with internal combustion engines have no regeneration of energy and its storage. By another words, they have low efficiency. Prior art aircraft engines, although much lighter than automobile engines are still too heavy, due to their size necessary for take-off and climbing power, and also due to relating heavy materials used in their construction. All this contributes to the shorter flight range. Prior art internal combustion engines are also very noisy and have a heat signature, which makes these airplanes in military missions easily detectable. Pure electric silent airplanes had been made, but they have short range and flight duration, due to the limited energy density of their batteries. Several hybrid electric airplanes are known, all in combination with solar electricity or fuel cells, which are expensive and weather dependent, or suffer from short life, and absence of the hydrogen infrastructure and lightweight hydrogen storage. None of them are practical for a rugged military or commercial use. Prior art electric motors and generators are also very heavy, due to the use of copper wires and solid steel shafts. Therefore, there is always a need to provide an airplane with longer flight range and/or flight duration on the same amount of fuel, while having silent stealth flight capability, and improved reliability and safety. Also there is a need to provide lighter engines and also lighter motors and generators. The airplanes and their propulsion systems of this invention do not suffer from prior art problems and provide for superior flight range, silent flight at the target, and additionally a safe power backup.
It has now been found, that a longer flight range and longer flight duration airplane than conventional equivalent airplanes can be made by combining a smaller ultra-light internal combustion engine propulsion system with an ultra-light electric motor and generator propulsion system, powered by a lightweight battery, which propulsion combination provides for an internal combustion electric hybrid airplane system. This hybrid propulsion system can replace the large conventional internal combustion engine in combustion-only airplanes, or the electric motor in electric-only airplanes. Because in any combustion-only airplane the engine is designed for take-off and climbing power, the same engine is oversized for cruising power, and consumes too much fuel, and has no regeneration of energy and its storage. By another words, it has low efficiency of the system. In this electric hybrid, a small combustion engine is used only for cruising power and therefore can be approximately 2-3× smaller and thus can run 2-3× longer time on the same amount of fuel than the large engine. This results in 2-3× longer flight range. The hybrid can be a parallel hybrid, or a series hybrid.
The simplified operation of the parallel hybrid airplane is as follows:
For take-off and climb both, the electric motor/generator and the combustion engine are used to drive the propeller. The electric motor should be preferably powered by a high energy density rechargeable lithium-ion battery.
During horizontal flight, only the small engine is used for cruising and a small extra power is used to generate electricity and recharge the batteries.
During descent, the engine is disconnected by a clutch and stopped, the propeller becomes a windmill and drives the electric motor/generator and fully recharges the batteries, to be ready for the next take-off. It should be noted, that the final approach for landing should be done with the restarted engine, or the electric motor, or both.
This electric hybrid airplane has additional advantages useful to the military. It has a temporary stealth capability. It can fly long range mission to the target using the engine, but during the approach it can switch to silent electric mode, execute the task and silently depart. For an extended silent electric flight, optional, preferably lithium-air batteries may be added at the cost of reducing the fuel range, which loss is replaced by the electric range. The electric motor then restarts the engine via clutch, to fly long distance back to the home base, becoming a generator and charges the battery during the flight home. Added safety is in its electric power backed by the batteries, if the engine fails. The plane will not be lost.
The simplified operation of the series hybrid airplane is as follows:
During take-off and climb both, the engine/generator, and the battery supply electrical current to the electric motor, which drives the propeller. The electric motor is briefly overloaded 3×.
During horizontal flight, only the generator driven by 3× smaller engine delivers electrical current to the electrical motor and additionally charges the battery , while having approximately ⅓ of fuel consumption rate of an equivalent conventional airplane.
Before the approach to the target, the engine/generator is stopped and silent flight continues by the electrical motor powered by the battery. When the mission is completed, the aircraft silently departs on electric power only.
After a safe distance from the target, the generator becomes second electrical motor and restarts the engine, which starts driving the generator again, and recharges the battery during the flight home.
During descent for landing, the engine/generator is stopped. The propeller becomes a windmill and spins the first electric motor, which becomes a generator and fully recharges the battery, to be ready for the next take-off.
The battery is protected from overcharge by an electronic interface and if necessary, it can be also charged on the ground from the electric grid. The same safety is provided by the battery back up, similar to the parallel hybrid. Also the additional batteries may be similarly added, for the extended silent flight.
The whole propulsion system without the fuel should not weigh more than the comparable, large conventional combustion-only equivalent aircraft engine. To accomplish this, the small engine, electric motor and generator, its controls and batteries should be designed from scratch and made from ultra lightweight materials only. For example, magnesium engine crank case and electrical motor/generator casings, carbon-carbon/ceramic composite cylinder block, aluminum and titanium hollow shafts, lithium batteries, and disc armature high torque electrical motor/generator may have flat aluminum wires or copper plated graphite fiber wires, instead of copper.
In case of compressed hydrogen fuel, this airplane would fly about the same distance as an equivalent conventional plane with petroleum fuel, due to its efficiency, and at much lower production cost than an equivalent fuel cell hydrogen fueled airplane.
The airplane can be built in any size, including 20-60 kg UAV, or as a manned aircraft, preferably with the lowest possible drag carbon fiber airframe, like a diamond-wing, tandem bi-plane with all electric controls, which will compound the benefits of both. The batteries should be in the wings, reducing the bending moment of the lift, which results in a lighter airframe.
In a jet version, the jet engine may be combined with a series electric motor/ducted fan, having over 30,000 RPM. When this application is used in a cruise missile, it will have also the silent electric mode at the target, achieving a total surprise.
The principal object of this invention is to provide any type of airplane with longer flight range and longer flight duration than prior art airplanes on the same amount of any desirable fuel.
Another object of this invention is to provide an airplane with temporary silent flight capability and electric power backup.
Another object of this invention is to provide a hybrid electric-internal combustion airplane with minimal size, weight, and drag airplane for the given mission.
Other objects and advantages of the invention will be apparent from the description and claims.
The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawing forming part hereof in which:
Like numerals refer to like parts throughout the several views and figures. It should, of course, be understood that the description and drawings herein are merely illustrative, and it will be apparent that various modifications, combinations and changes can be made of the structures and the systems disclosed without departing from the spirit of the invention and from the scope of the appended claims.
When referring to the preferred embodiments, certain terminology will be utilized for the sake of clarity. Use of such terminology is intended to encompass not only the described embodiment, but also all technical equivalents which operate and function substantially the same way to bring about the same results.
Present invention employs a novel internal combustion-electric hybrid propulsion system, which substantially increases the flight range and the flight duration of any type, and any size airplane, manned or unmanned, and also provide for temporary silent stealth flight, and additional safety, which results in improved airplanes with many advantages.
This hybrid systems can be a parallel hybrid or a series hybrid and can use any desirable fuel. In combustion-only airplane the engine is designed for take-off and climbing power, but the engine is oversized for cruising power, and consumes too much fuel, and has no regeneration of energy and its storage, which results in low efficiency of the system. In these electric hybrids a small internal combustion engine is used only for cruising power and therefore can be approximately 2-3× smaller than the engine in an equivalent conventional airplane, and thus can run approximately 2-3× longer time on the same amount of fuel. This results in approximately 2-3× longer flight range.
The equivalent airplane is understood to be one having the same, or approximately the same size, weight and purpose. It is also understood that at least one or more than one of these hybrid propulsion systems can power the airplanes of the invention.
Referring now in more detail, particularly to the drawings of this patent and
The propeller 6 can be puller type, or a pusher type.
When this parallel hybrid propulsion system 1A is installed into an airplane, the simplified operation of the parallel hybrid airplane is as follows:
For take-off and climb both, the electric motor/generator 2 and the combustion engine 1 are used to drive the propeller connected by the clutch 5. The electric motor 2 should be preferably powered by a high energy density rechargeable lithium-ion battery 3.
During horizontal flight, only the small engine 1 is used for cruising, and an extra power may be used to drive the generator 2 to generate electricity and recharge the batteries.
The clutch 5 may stay connected until the battery 3 is fully charged.
During descent, the engine 1 may be disconnected and stopped. The propeller 6 becomes a windmill and drives the electric motor/generator 2 and fully recharges the battery 3, if necessary, to be ready for the next take-off. It should be noted, that the final approach for landing should be done with the restarted engine, or electric motor, or both. The battery 3 is protected from overcharge by the controller 4, which in electric motor drive mode also controls the motor 2 per pilot's commands, and in an unmanned airplane via a radio, or a computer controls. Similarly, the electric clutch 5 is also controlled, as well as the start and stop of the engine 1.
This electric hybrid airplane has additional advantages useful to the military. It has a temporary stealth capability. It can fly a long range mission to the target using the engine, but during the approach it can switch to silent electric mode, execute the task and silently depart. For an extended silent electric flight, additional, optional, preferably lithium-air batteries 13A may be added with a switch or relay 9, at the cost of reducing the fuel range, which loss is replaced by the electric range. The electric motor 2 then restarts the engine via the clutch 5, to fly long distance back to the home base, becoming a generator and charges the battery 3 during the flight home. Added safety is in its electric power backed by the batteries, if the engine fails. The plane will not be lost.
Another embodiment of the invention is shown in
During take-off and climb both, the engine/generator 1B and 2A and the battery 3A supplies electric current to the electric motor 5A, this drives the propeller 6. The electric motor is briefly overloaded approximately 3×.
During horizontal flight, only the generator 2A, driven by approximately 3× smaller engine 1, delivers electric current to the electric motor 5A and additionally charges the battery 3A, at approximately 3× lower fuel consumption rate.
Before the approach to the target, engine/generator 1B and 2A is stopped and silent flight continues by the electric motor 5A powered by the battery 3A. When the mission is completed, the aircraft silently departs on electric power only.
After a safe distance from the target, the generator 2A becomes second electric motor and restarts the engine 1B, which starts driving the generator 2A again, and recharges the battery 3A during the flight home.
During descent for landing, the engine/generator may be stopped. The propeller becomes a windmill and spins the first electric motor 5A, which becomes a second generator and fully recharges the battery if necessary, to be ready for the next take-off.
The battery is protected from overcharge by electronic control 4, and if necessary, it can be also charged on the ground from the electric grid by a well known charger. The same safety is provided by the battery back up, similar to the parallel hybrid. Also, the optional additional batteries 13A with a switch or relay 9 may be similarly added, for the extended silent flight.
Another embodiment of the invention is shown in
Another embodiment of the invention is shown in
Another embodiment of the invention is shown in
It is apparent to a person skilled in the art, that this airframe can be also combined with the series hybrid electric propulsion system 2B in the pusher configuration (not shown),similar to
Another embodiment of the invention is shown in
The similar type airframe can be also combined with a jet engine-electric series hybrid propulsion system 47, as shown in
The above described propulsion systems without the fuel should not weigh more than the equivalent, large conventional combustion-only equivalent aircraft engines. To accomplish this: The small engine, electric motor/generator, and batteries should be redesigned and made from ultra-lightweight materials only. For example: magnesium alloy engine crankcase and electric motor and generator casings, carbon-carbon composite cylinder block with a ceramic lining(s), aluminum and/or titanium hollow shafts, ceramic bearings, lithium based batteries, and disc armature high torque electric motor/generator may have flat aluminum wires or copper plated graphite fiber wires instead of copper. Flight controls of all control surfaces, like ailerons, flaps, elevators, rudders, louvers and clutches, engines and motor power controls etc. should be preferably all electric, and may be also remote radio and/or computer controlled.
In case of hydrogen fuel, these airplanes would fly about the same distance as an equivalent conventional plane with petroleum fuel, due to their efficiency, and at much lower production cost than a fuel cell hydrogen fueled airplane. The hybrid electric airplanes of the invention can be built in any size, from micro-unmanned air verticals (MUAV's) up to large manned cargo planes and airliners, and can have any type of airframe.
It should, of course be understood that the description and the drawings herein are merely illustrative and it will be apparent that various modifications, combinations and changes can be make of the structures disclosed without departing from the spirit of the invention and from the scope of the appended claims.
It will thus be seen that a safer, longer flight range and longer flight duration airplanes with silent flight capability have been provided with which the objects of the invention are achieved.
