Patent Application
20090274557
Not Applicable
Not Applicable
Not Applicable
This is a propeller which can have various applications including but not limited helicopter rotors, airboat rotors, variety of air-fans including ceiling and hand fans and other devices which contemplate utilizing blades to direct airflow. Historically, most rotors utilize long solid not retractable blades which make use of the rotors very cumbersome and seriously limit effectiveness of the rotors. Good example of such cumbersome use would be a case of a helicopter rotors, and associated with it necessity to disassemble or remove the blades from the rotor every time, say, a helicopter must be either stored or transported. Given the length of the blades and labor intensity associated with blade removal and reinstallation, flexible variable blades which require no disassembly or removal when the helicopter is to be stored or transported, present very interesting and useful invention which can revolutionizes the very use of the rotors be this in large aircrafts; air powered watercrafts or as small a devices as handheld cooling fans.
While some attempts have been made in prior art including U.S. Pat. Nos. 4,029,435, 4,086,024, 6,450,446, 6,837,457, 7,004,427, to resolve the issue of bulkiness and labor intensity attributed to storing and transporting of rotor based aircrafts precisely because of the necessity to disassemble and remove the rotor blades due their large length and lack of flexibility, all such known attempts purport to utilize solid blades to tackle the problem, concentrating on the effort to make the blades retractable rather then flexible and variable.
Present invention approaches these problems from a new, innovative angle by advancing the idea of flexible blades which length can be varied depending on the necessity, so that no need of removing the blades any longer exists. The invention utilizes centrifugal force to bring the blades from their retracted position to the full length within seconds of commencement of the rotor operation, and vice versa, bringing the blades to their retracted position which takes little space, as the centrifugal force subsides upon cessation of the rotor motion. Such design enhances significantly the safety of the aircraft crew as any slowing down on the rotation of the propeller including emergencies like engine stall or blade crush, when the velocity of the rotation subsides beyond certain point, retracts the blades and in so doing eliminates misbalancing the aircraft and allows catapulting of the crew when needed.
The invention has as its aim and object to increase the efficiency, versatility and safety of machinery which utilizes propellers to provide thrust for propulsion of the aircrafts such as helicopters. In order to achieve this aim, utilization of the length variable blades made of flexible material is made into the main object of this invention. This arrangement allows making adjustable the length of the blades and correlating it with the desired lifting force and carrying capacity of the aircraft. It also allows adjusting the angle of the blade to control the pitch. As the blades are reeled around a barrel upon retraction, which is made into an automatic process which depends on the velocity of the propeller rotation; potential for misbalancing of the aircraft is substantially decreased, elevating significantly the safety of the aircraft and its crew and making possible the catapulting of the crew, which is usually prevented by the rotating of the propeller with regular fixed-length blades. At the same time, the idea is very different from a case of the fixed-length retractable blades. It is so because, fixed-length retractable blades are only given the capability to retract into allocated compartments within the aircraft while the length of the blades remained unchanged, doing very little to address bulkiness and safety of the rotor. Here, blades are made of the flexible material which allows for immediate retraction of the blades into full length needed for proper operation of the rotor, and retraction of said blades into their elastic state when rotation of the rotor ceases.
The present invention herein is a propeller which consists of the rotor disc assembly (1), two or more flexible variable-length blades (2), a precise number of which depends on the desired lifting force; carrying capacity and the airflow involved in the process of the aircraft take off and retention in the air; device or devices, which control retraction of blades, and devices which controls blade pitches (3). The blade represents a flexible strip made of steel composite or any other suitable material. The flexible nature of the strip and the fixture of the inner end of each blade on the barrel (4) located within the rotor disc assembly on which blades are reeled when retracted (
Each barrel on which the blades are reeled represents a drum (6) situated inside the rotor disc assembly which rotates around the perpendicular axis of the assembly. If design of the aircraft requires only two blades, the inner ends of both blades are affixed to the same single barrel (4) around which the blades (2) are reeled upon retraction (
The foregoing is considered as illustration only of the principles of the invention. Further since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and, accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
