The invention is the unmanned aircraft specified in the introduction to patent claim 1.

The invented solution is particularly suitable for territorial supervision, control, and reconnaissance, as well as for tasks such as transport, tracking people across terrain, and rescue services. The invented solution can be used particularly effectively in transport and rescue activities, for example in difficult terrain or otherwise difficult and/or dangerous conditions, for example during bad weather.

Unmanned aircraft that can lift a person out of water and transport said person to a support ship or over land are not commonly in use. It is well known that manned aircraft have been used for such tasks, including vehicles like helicopters, where a pilot with suitable training and licenses has been required to pilot the vehicle. The pilot and often other members of supporting personnel require their own space onboard the vehicle, which may enlarge the aircraft and require additional devices with which the pilot can control the craft. The pilot and the space and devices he needs make the aircraft heavier, which makes it more expensive to manufacture the aircraft and reduces the deployable payload capacity. Pilots may also become injured or even die when piloting aircraft under difficult terrain or weather conditions or in otherwise hazardous environments. The additional weight imposed by the pilot and other members of the crew also increases the fuel consumption of the aircraft. An additional shortcoming is the slow travel speed of regular helicopters, being around 130 to 200 km/h, meaning that the trip to the operations area may take too long. A further shortcoming consists of the requirements, licenses, and working hour limitations imposed on pilots, such as mandatory resting periods specified in aviation regulations and the like.

Unmanned aircraft currently existing at the level of known technology have such limited lifting capacities that many rescue activities, such as ocean and swimming rescue missions, cannot be completed using them. In addition, known unmanned aircraft are mainly battery-powered, meaning that the battery capacity limits their operating time. Said operating time is usually limited to only 70 to 80 minutes. The cruise speed of unmanned aircraft is also not great. This is why their range is limited, because much of the operating time needs to be reserved for actions taken at the operations site, after which the trip back still needs to be made successfully.

One problem with unmanned aircraft especially is the rotor blades freezing over. Under suitable circumstances, ice tends to accumulate over almost the entire blade due to the variable rotor angle of attack.

The purpose of this invention is to eliminate the shortcomings identified above and to create an affordable, unmanned, and fast aircraft with light empty weight and sufficient payload capacity and lifting capacity to reach the operations site quickly and, when there, to be able to lift even heavy loads or rescue people from e.g. water when suitably equipped. The purpose of the invention is also to create an unmanned aircraft that can perform rescue, transport, surveillance, supervision, and reconnaissance missions under remote controls such that the device operator does not need to accompany the aircraft. Yet another purpose is to create an unmanned aircraft that can stay connected and work together with other manned or unmanned aircraft and ground vehicles. Yet another purpose is to create an unmanned aircraft that can be operated with remote controls at a sufficient level of operational reliability under difficult and/or hazardous terrain and weather conditions and that can operate independently, at least in part, on the basis of its independently made observations and pre-given instructions. What has been presented in the characteristics section of patent claim 1 is characteristic of the invented unmanned aircraft. What has been presented in other patent claims is characteristic of other applications of the invention.

In order to achieve its purpose, the invention is an unmanned aircraft that comprises an airframe, a propulsion engine with control and operating systems, two coaxial rotors that turn in opposite directions, and which aircraft has been equipped to operate through remote controls. In order to achieve the highest possible cruising speed, the rotational axis of the tail rotor is along the lengthwise direction of the aircraft.

An advantage of the invented aircraft is for instance having reduced manufacturing costs when compared to manned aircraft of the same size, because many such systems and equipment can be omitted that are absolutely required for manned aircraft to be able to operate. The invented aircraft is also smaller and lighter in weight than similar manned aircraft, because no room is required for a pilot and associated equipment. Because no human payload needs to be accounted for in the design, a more efficient and compact structure can be achieved. At the same time, the payload of the aircraft can be increased, because the payload capacity required for a pilot can be used for other purposes . One advantage is the high speed and extended operating time of the aircraft, meaning that the operations area can be reached quickly, for example when performing rescue missions, and the operating time of the combustion engine-powered aircraft is longer than that of battery-powered unmanned aircraft. A corresponding advantage is the long operating range, allowing the aircraft to operate under remote controls or independently at a distance of up to approximately 130 km from the operator. Another benefit is that the aircraft can reach places that are impossible or too dangerous for humans to reach. This allows transporting persons, supplies, or materials to even difficult destinations or away from such destinations.

Another advantage is that, thanks to its good communications connections, several manned or unmanned aircraft and any manned or unmanned ground vehicles in contact with them can be controlled to operate together, at the same time, or in sequence. In this case, each aircraft can be connected for example to existing marine rescue systems, and they can be used for land, sea, air, and traffic controls.

If remote controls cannot be properly used due to interference, the aircraft can complete rescue missions and payload transports independently as well, aided by means such as computer vision. If the aircraft loses connection to the operator, it can return to a predefined location on its own.

The aircraft can be assigned several missions and/or destinations in advance. When the aircraft is given a mission for example between two locations, it can operate independently and choose the best procedure by employing artificial intelligence. Another advantage is the capability of the aircraft to pair with a manned or unmanned ground vehicle. In this case, the ground vehicle and its paired aircraft have equipment to locate each other automatically. The equipment use means such as GPS positioning and radiolocation. The aircraft can arrive at a desired location or person if the location or person employs a suitable positioning device.

Another advantage is that the aircraft carries various control and detection devices and means to establish various connections. Thus, the coast guard or other authorities do not need to be contacted for every task.

Another advantage is that the aircraft does not require a pilot who could be exposed to dangers. The remote-controlled aircraft also does not require a pilot's license or piloting skills to be operated. The operator can control the aircraft without needing to be a licensed pilot who needs to comply with mandated resting periods. This means being able to maximise operative actions in rescue missions for example, as the operation can be continuous.

The aircraft carries cameras, a radar, a GPS system, various communications systems, a gyroscope system, a collision prevention system, and other systems that allow the operator to see where the aircraft is and what there is in its surroundings from several kilometres away. The gyroscope system makes it possible to perform in-flight operations such as landing, directional stability, banking, maintaining altitude, taking off, turning, and navigating automatically, so the pilot does not need actual piloting skills or pilot training. It is also quick to learn how to operate the craft. Another advantage is that the invented unmanned aircraft features rotor blades that prevent freezing and/or actively remove any accumulated ice. Anti-freezing and/or ice removal is achieved either by means of blade heating and/or vibrating elements .

Another advantage is that the dual rotor structure of the invented unmanned aircraft achieves a lifting capacity greater than normal for the invented craft. The lifting capacity is approx. 70% greater than the lifting capacity of a single-rotor aircraft of similar size.

The invention is explained in more detail below by means of application examples and by making reference to the attached simplified and schematic drawings, in which figure 1 presents a top view of an unmanned aircraft according to the invention, figure 2 presents a side view of the unmanned aircraft in figure 1 , figure 3 presents a front view of the unmanned aircraft in figure 1, and figure 4 presents a top view of an invented aircraft equipped with a replacement cartridge and working together with an unmanned ground vehicle assisting the aircraft .

Figures 1-3 present an aircraft according to the invention. The aircraft is shown from the top in figure 1, from the side in figure 2, and from the front in figure 3. The aircraft 1 according to the invention is an unmanned, remote-controlled aircraft whose primary components are a composite frame 2 including a hollow space, two stacked and mutually coaxial rotors 3a and 3b, which rotate in mutually opposite directions, front winglets 5 on both sides of the frame 2, rear winglets 6 on both sides of the frame 2, a stabiliser 10 protruding directly down from the rear of the frame 2, and a tail rotor 7 at the rear of the frame 2, rotating on a transverse vertical level in relation to the lengthwise direction of the frame 2. The aircraft 1 further comprises skids 9 below the frame for landing on the ground or other surface and an at least partially transparent canopy-like hatch 8 at the top of the frame, through which the interior of the frame 2 can be accessed to install, adjust, and repair the various devices, and through which the exterior of the frame can be viewed from within the frame 2.

The tandem rotor structure, i.e. having two rotors 3a and 3b stacked on top of each other and rotating in mutually opposite directions, gives the invented aircraft 1 a lifting capacity that is greater than standard. The lifting capacity of a helicopter with an engine of 300-400 hp of nominal power and a single primary rotor of 5-6 m in diameter is approx. 600-650 kg. The lifting capacity of the invented aircraft with an equally powerful engine and a tandem rotor of equal diameter is approx. 70% greater, that is approx. 1, 000-1, 100 kg.

Advantageously, aircraft 1 features a control and operating system, a fuel tank and a propulsion engine using the fuel in the tank, and a transmission system to rotate the rotors 3a, 3b, and 7 and power the actuators of the aircraft. The propulsion engine can be used to power some of the actuators of the aircraft and also to recharge the battery or battery pack of the aircraft, which acts as a power source. Advantageously, the propulsion engine is a turbocharged piston engine generating some 300-500 horsepower, but it could as well be any other suitable engine. The aircraft features equipment for remotely starting the propulsion engine. Start-up has been arranged to be achieved by means of a radio connection or other means of remote control. Start-up can also be achieved independently by means of pre-programming or sensors, when the sensory equipment of the aircraft detect activity in the environment.

If needed, there may be more than one engine. For example, the tail rotor 7 can be provided with its dedicated engine, which could also be an electrical engine. The tail rotor 7 allows the aircraft to achieve a higher cruise speed than regular unmanned aircraft, easily exceeding 200 km/h, advantageously even exceeding 230 km/h. The high speed makes it possible to reach the operating area quickly, giving more time for actual operations on-site .

The tail rotor 7 turns in a transverse direction relative to the direction of travel of the aircraft, i.e. its axis of rotation is in the direction of the lengthwise axis of the aircraft. Advantageously, the tail rotor 7 can be housed in an adjustable drum, improving the thrust of the rotor. One such solution is a ducted fan rotor structure. The rotor structure presented in figures 1-4 is a standard structure not featuring a drum surrounding the tail rotor.

Advantageously, the invented aircraft 1 is equipped with a rotor blade anti-freeze feature, which solution removes ice from and/or prevents the formation of ice on the blades of the primary rotors 3a and 3b, and also the tail rotor 7 if needed. The anti-freeze feature is achieved either by means of blade heating and/or vibration elements attached to the blades, such as piezoelectric elements. The heating solution is achieved either by electronic means or by means of liquid circulating inside the rotor blade.

Heating by means of liquid circulating inside the blade is an affordable and simple means in a combustion engine-powered aircraft, as the propulsion engine generates vastly more excess thermal energy than what is required for heating the blades. The blade anti-freeze and/or ice prevention can be achieved fully by using the excess heat from the engine. One solution in this case could be to have one or more tube loops running inside each of the blades of the rotors 3a, 3b, and 7, into which the heating liquid is taken from the engine coolant circulation. In this case, the cooler for the propulsion engine could be smaller than normally. One solution could be to implement a cellular structure that enables the circulation of the heating liquid, which could advantageously be connected to the metallic wear surface at the front edge of the blade. In this case, the cellular structure also constitutes part of the supporting structure of the blade.

Advantageously, the blade heating liquid arrangement is connected to the coolant circulation system of the engine or another warm liquid circulation system by means of pressureresistant, secure, and dependable quick couplings or regular couplings, for example hydraulic couplings or chemical tube or pipe couplings. The structure or blades of the rotors 3a, 3b, and 7 could also feature an electric valve or similar valve to shut off the liquid circulation into either a single blade or the entire rotor. The mentioned reliable liquid circulation system closing structures make it possible to replace the blades quickly and safely. Advantageously, the aircraft could have a sensor arrangement to monitor the temperature of the blade heating liquid and to keep it at the correct temperature. The sensor arrangement could comprise at least one or more thermal sensors in the structure or blades of the rotors 3a, 3b, or 7 and a reliable liquid pump, such as a gear pump.

Air bubbles in the heating liquid circulation system can influence the weight of the blades such that the balancing of the aircraft is thrown off. This is why the aircraft can additionally feature an air bubble removal unit that has been arranged to remove air bubbles from the heating liquid circulation.

There is an assembly of fixing arrangements 11 in connection with the frame 2 of the aircraft, which can be different from each other and used to attach for instance various transport pods, devices, or payloads. Figure 2 shows only two fixing arrangements at the bottom of the frame 2, but there can be more of these, even on the sides of frame 2 and on the front winglets 5.

The transport pod can be fully closed or a partially open replacement cartridge 15, which can vary according to use purpose. One replacement cartridge 15 is presented in the simplified figure 4. Various functional systems and/or transportable items have been advantageously placed inside the cartridge. Advantageously, the fixing arrangement 11 and replacement cartridges 15 are equipped with a quick lock mechanism, which makes it possible to quickly disconnect, attach, and replace the replacement cartridges 15. The fixing arrangement 11 further comprises quick couplings for establishing electrical and data connections in between the replacement cartridge 15 and the aircraft 1. By means of the quick couplings, electrical and data connections are established with such functional systems and equipment in the replacement cartridge that require electrical power to function and control commands received via a data connection to become active. Advantageously, the quick lock mechanism and quick couplings are arranged to operate together in such a way that when a replacement cartridge 15 is fixed in place, the electrical and data connections are established automatically via the quick coupling. The quick lock can be achieved for example by magnets, at least in part.

The aircraft 1 is furthermore advantageously equipped with remote controls and/or an independently operating lifting arrangement that comprises a lifting assembly with a lifting strap and a lifting basket or a similar arrangement into which a rescued person can climb or can be placed and in which the person can be transported to receive the required assistance. In this case, the lifting arrangement works as a rescue arrangement. Advantageously, the lifting arrangement with its actuators, control systems, and equipment is placed inside the frame 2 of the aircraft. The lifting arrangement and its actuators and equipment can also be placed in one of the above- mentioned replacement cartridges 15, which is attached to the fixing arrangement 11 of the aircraft. In an aircraft thus equipped, the lifting system is one outfitting option among others .

Advantageously, the rescue arrangement also includes a rangefinder, for instance a laser rangefinder for measuring the distance of the bottom of the lifting basket from the surface of the ground or water.

The lifting basket can additionally be equipped with a pressure sensor that is arranged to measure the weight of the load/person in the basket and compare it to the maximum lifting capacity of the aircraft. The pressure sensor can also be used to measure whether the basket is loaded or not. The lifting basket can additionally feature a safety mechanism that has been arranged to release the lifting arrangement of the aircraft if the load is too heavy to lift or if the basket has become stuck on something .

The rescue arrangement can also include a stretcher for transporting a patient when quick transport to receive treatment is required and the terrain is slow and difficult to traverse. In this case, the aircraft can be used to transport a patient on a stretcher that is equipped with suitable fastening solutions, advantageously by using quick locks attached to the lifting strap of the aircraft.

The aircraft can also feature a camera arrangement that is directed or can be directed to point down and that can be used to see what is happening by the basket and check that the basket is loaded and ready for lifting up for transport. Advantageously, the camera arrangement also comprises a video camera that shoots and submits real-time video footage.

The laser rangefinder can also be used to measure the precise distance of the lifted load from the surface of the ground or water or any other surface onto which the load should be lowered or off which it should be lifted.

The various actuators and equipment of the remote controlled aircraft 1 include various surveillance systems, camera devices, radars, gauges, and other observation equipment as well as various means of communication, allowing the unmanned aircraft to be used as for example a mobile base of operations in support of operations carried out by the authorities. The aircraft can also be used for surveillance, monitoring, or reconnaissance. The equipment of aircraft 1 make it possible to avoid contacting the coast guard or other authorities in many cases. The aircraft also carries equipment to get the aircraft to independently return to a pre-defined location, for example if contact with the operator is lost, the propulsion engine is running out of fuel, or the operating system detects an emerging or occurred mechanical or electrical fault that causes a serious hazardous situation.

The operator of the remote-controlled aircraft does not need to maintain visual contact with the aircraft to control it. The aircraft may feature for instance instrument flight capability, a computer vision functionality and an associated video camera system, a gyroscope system, a radar system, light radar or lidar equipment, laser scanning equipment, a speed dial, an odometer, a satellite positioning device such as GPS, and various other observation equipment and sensors that can prevent the aircraft from colliding with other objects and perform various other tasks.

The controls of the aircraft are arranged such that the operator controls the aircraft on the basis of the data supplied by the aircraft itself. For example, the operator can by means of the video camera and light radar system see the terrain and other events around the aircraft in real time, and the GPS system and/or other observation equipment make it possible for the operator to know the real-time location of the aircraft. The aircraft thus features connection equipment and instrument flight systems required to control the aircraft remotely without visual contact with the aircraft. By such means, the aircraft 1 can be controlled from several kilometres away, advantageously from a distance of at least 130 km. The data required for remote control include direction of flight, altitude, airspeed, GPS positioning data, and visual real-time video camera feed, i.e. video data showing the area over which the aircraft is being operated by the operator. The gyroscope system of the aircraft is arranged to manage the flying independently after receiving flight directions, such as the destination, from the operator.

The aircraft also features equipment for performing various independent tasks, such as rescue and payload transport missions. Such an arrangement is needed in case the remote control capability is reduced due to interference or similar reasons. The independent operating capability is advantageously realised by means of computer vision, which can also be combined with artificial intelligence functions.

The aircraft also features equipment for returning to a predefined location in case the aircraft loses contact with the operator .

Aircraft 1 also carries operating equipment for independent operations when the aircraft has been given some mission, for instance travelling between two different locations. In this case, the aircraft will travel between the designated locations and perform its mission independently, until the mission is completed or cancelled.

Aircraft 1 features equipment making it possible to pre-assign several pre-defined locations and/or missions to the aircraft. The aircraft can perform the tasks automatically in the order they are given. Additionally, the artificial intelligence onboard the aircraft can also make independent decisions about the best possible operating procedure and order of execution.

Advantageously, the aircraft also carries identification equipment that allow the aircraft to identify people, objects, and places in the video feed it collects and to submit the data to the operator or another pre-defined location.

The aircraft also features equipment to survey the area over which it travels in order to store route and survey data and to learn the route it has travelled. Thus, the aircraft can be sent to fly the same route later. Such equipment can include computer vision, laser scanning, and lidar systems.

The aircraft can also feature equipment for the remote activation of the aircraft. In this case, the aircraft can be taken, or it can fly, to the operating area, and it can be activated remotely or be programmed to activate automatically if the observation and surveillance systems cause such an activation. In such a situation, the aircraft can remain operational in the area for weeks. The aircraft can feature an automatic battery pack recharging arrangement. Once the battery pack charge is depleted, the engine starts and recharges the batteries to full by means of charging equipment connected to the engine. In this way, the systems and equipment of the aircraft will always receive the electrical energy they need.

Advantageously, the remote-controlled and unmanned aircraft 1 has cooperating systems to get it to work together with a remote-controlled and unmanned ground vehicle 12. Figure 4 is a schematic representation of such a situation. In figure 4, the ground vehicle 12 is carrying a load 13 and maintains a wireless connection 14 with aircraft 1, which can for example guide the ground vehicle 12 to its destination.

Advantageously, the ground vehicle 12 and aircraft 1 have locating systems for finding each other automatically. The locating equipment use means such as GPS positioning and/or radiolocation. The ground vehicle 12 and aircraft 1 can arrive at any location where there is a locating device compatible with their locating devices, including individual persons who carry such locating devices.

Importantly, the unmanned ground vehicle 12 is light in weight, and its paired unmanned aircraft 1 is equipped with such lifting capacity and equipment that allow the aircraft 1 to transport the ground vehicle 12 to the designated operating area.

Advantageously, the unmanned ground vehicles 12 and aircraft 1 feature interoperation systems that allow several ground vehicles and/or aircraft to work together as a group. In this way, versatile and efficient groups can be formed for various tasks, for instance in difficult or dangerous conditions or environments. The range of the remote controls is at least 180 km when good HF radio equipment are used, and an internet connection can also be used for issuing commands. The ground vehicle 12 and aircraft 1 also feature satellite connection systems to be used in areas where they can be used.

Recycled materials can be used in the manufacturing of the aircraft according to the invention. Advantageously, the frame 2 for instance can be made with recycled materials, at least in part. Additionally, at least some of the aircraft components can be made by printing, using for example 3D printers.

The aircraft according to the invention comprises equipment that allow it to achieve a high level of self-control and an ability to fly to the designated target without assistance or a flight-capable operator.

Advantageously, the aircraft according to the invention also comprises testing equipment to test the functionality of connections between the replacement cartridge 15 and the aircraft 1 control system as well as between the lifting basket and the aircraft 1 control system. The testing can be performed either automatically or manually. If a connection between the lifting basket and aircraft does not work correctly, the testing equipment will notify of a fault. In this case, the aircraft will not lift the basket or start moving until all systems are operational .

A similar testing arrangement also pertains to the attachment of the replacement cartridges 15. Different replacement cartridges have their own standard tests, and the aircraft 1 features identification equipment by means of which it can detect the type of the replacement cartridge 15 and the mission description associated with it automatically based on the test. After identification, the flight and power characteristics are determined according to the identification data coming in from the replacement cartridge 15.

Thus, the aircraft 1 can be quickly modified with replacement cartridges 15 and their equipment as well as identification data for various tasks depending on the use purpose.

It will be clear to industry professionals that the invention is not limited only to the examples mentioned above, but that it may vary within the framework set by the following patent claims. Thus, instead of a single stabiliser, the tail of the aircraft can feature two or even three stabilisers of the same type .

It will also be clear to industry professionals that the air- craft can also be hybrid-powered, in which case the rotors can be used by means of one or more electrical engines receiving their power from batteries that are automatically recharged by the actual propulsion engine, instead of or simultaneously with the turbocharged propulsion engine.