Home
As costs begin to descend in the near future with the onset of mass production of superconducting wire, this opportunity will present itself.
The idea is to mount a small, lightweight superconducting electric motor with a folding prop to a hang glider, plug it into a superconducting extension cord, take off and gain altitude until the extension cord pops off.
No tow rope. No tow winch. No tug. No weaklinks. No tricky running takeoff. No dangerous tow-force vectors. The possibility of lock-out is completely eliminated.
I am thinking the safest way to do this would be to install the prop at the back of the harness, but maybe it could also be mounted to the glider as pusher or tractor. Once the extension cord releases, the prop would retract and you would have a very low drag setup.
The pilot would take off from the back of a pickup fitted with a pay-out spool for the extension cord and an electric generator. The truck could follow a road as in conventional towing, or use an open space like a parking lot and the pilot could spiral up like working a thermal. At release altitude, the plug would disconnect and descend with a small drag chute so the extension cord could be spooled in without touching the ground. Note that the spool would be powered by a small electric or perhaps a hydraulic motor sufficient only for preventing slack during payout and bringing in the line following release.
The extension cord would be made of superconducting wire, very thin and light, wrapped in a sturdy, lightweight insulating material. Unlike towing, there would be very light tension on the extension cord. It would be attached below the harness CG point. The forces contributing to the pull would be a combination of air resistance and the weight of the extension cord itself. In a climbing spiral, the air resistance would be minor. The force vector on the line in an upward spiral would be close to gravity, perhaps unnoticeable.
Because the power source is not on the glider, a great deal of weight compared to either internal combustion or electric battery propulsion is completely eliminated, along with all danger from igniting fuel or short circuiting batteries in a crash.
__________________________
How do Superconducting Motors Differ from Conventional Motors?
Superconducting motors are new types of AC synchronous motors that employ HTS (high temperature superconductor) windings in place of conventional copper coils. Because HTS wire can carry significantly larger currents than can copper wire, these windings are capable of generating much more powerful magnetic fields in a given volume of space.
More Compact Size
Advances in coil design make it possible for a superconducting machine to match the power output of an equally rated conventional motor with as little as one-third the size and weight. The smaller size and compact nature of superconducting motors allows them to be manufactured at lower cost than equivalent conventional motors.
Additionally, the replacement of conventional copper rotor windings with non-resistant HTS coils results in sharply reduced electrical losses in the rotor. The increased electrical current in the motor’s rotor results ultimately in the increased power density (and hence smaller size). The HTS motor’s smaller size means it is significantly lighter, and therefore can be utilized in new and innovative ways. In addition, the motor’s increased efficiency results in lower operating costs than conventional motors.
Noise Reduction
HTS AC synchronous motors also have no iron teeth in the armature (stator windings), not only contributing to their smaller size and lighter weight, but also removing a significant source of motor noise.
More info: American Superconductor
http://www.amsc.com/library/index.html
