Small Business Innovation Research/Small Business Tech Transfer
Non-Contact Magnetic Transmission For Hybrid/Electric Rotorcraft
Project Description
Electric propulsion has the potential to revolutionize aircraft design and architecture. A distributed electric propulsion system for a VTOL aircraft can exploit aerodynamic benefits increasing the lift to drag ratio by 4 to 5 times (Fredericks et al, Intl Powered Lift Conf, Aug 2013) to that of conventional rotorcrafts. Basic physics principles can demonstrate that weight and efficiency optimized electric motors and propellers of the same power rating will rotate at different rpm making a transmission system/gearbox desirable. High speed electric motors have excellent specific power whereas low speed propellers are more efficient. In distributed propulsion systems there may be numerous individual propulsors making gearbox maintenance a significant effort that will detract from the potential cost savings of electric propulsion. We propose a magnetic transmission (magnetic gearbox) design that will allow optimal matching of high specific power electric motors to efficient propellers for use on electric or hybrid-electric air vehicles. The proposed magnetic transmission will have a mass of no more than an equivalent rated mechanical gearbox. Unlike conventional gears the magnetic transmission will have no lubrication requirements, gear tooth wear, will be immune to vibration fatigue in the gear teeth, and will have minimal acoustic noise. If overloaded the design will benignly "slip a tooth" and then re-engage. We propose to design, build and test a magnetic transmission optimized for specific torque, and compare the weight of the system to an optimal mechanical gearbox of the same power. We will also perform design studies to show how a magnetic gearbox could scale up to a helicopter main rotor gearbox.
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Anticipated Benefits
NASA has done significant research in electric and hybrid/electric propulsion. Non-contact magnetic transmission technology would be a key enabler for full sized aircraft propulsion systems in order to meet the specific power requirements. Furthermore, some NASA research areas are focused on cryo-cooled propulsion. The magnetic remanence of the rare earth magnets we will use in the magnetic trasnmission actually increases as the magnets are cooled down to 100 degrees K. This potentially results in a ~30% increase in torque capability for a magnetic gearbox that is cryo-cooled.
At first, rotorcraft applications would be the most obvious for our magnetic transmission technology because the maintenance cost of the system could be reduced while increasing reliability without impacting weight. Key rotorcraft manufacturers could start building technology demonstrators using our technology within the next several years either with hybrid electric or conventional drive systems if the basic development proposed in this Phase I effort is completed and the technology is proven effective. We have been in contact with various research groups working on electric and hybrid electric vehicles, and they have expressed interest in our motor and hybrid-electric drive technology. Terrafugia Inc. with their new TFX VTOL personal air vehicle design could benefit tremendously from this magnetic transmission technology, along with many other personal air vehicle concept designers. Terrafugia has discussed with us how noisy mechanical gearboxes are and would love an alternative. More »
At first, rotorcraft applications would be the most obvious for our magnetic transmission technology because the maintenance cost of the system could be reduced while increasing reliability without impacting weight. Key rotorcraft manufacturers could start building technology demonstrators using our technology within the next several years either with hybrid electric or conventional drive systems if the basic development proposed in this Phase I effort is completed and the technology is proven effective. We have been in contact with various research groups working on electric and hybrid electric vehicles, and they have expressed interest in our motor and hybrid-electric drive technology. Terrafugia Inc. with their new TFX VTOL personal air vehicle design could benefit tremendously from this magnetic transmission technology, along with many other personal air vehicle concept designers. Terrafugia has discussed with us how noisy mechanical gearboxes are and would love an alternative. More »
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Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| LaunchPoint Technologies, Inc. | Lead Organization | Industry | Goleta, California |
Glenn Research Center
(GRC)
|
Supporting Organization | NASA Center | Cleveland, Ohio |
Primary U.S. Work Locations
-
California
-
Ohio
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