The Lifter 4 Power-Supply
The
Lifter 4 indoor tests were performed using the Hvolt series
power-supply from Information Unlimited. The critical voltage
required to achieve lift is 17.5 kV -- however, increasing
the voltage correlates with an increase in thrust.
American
Antigravity conducted extensive Lifter 4 testing from August
to October of 2002. Due to lightweight construction materials
and adverse humidity effects, our initial Lifter 4 prototype
was retired in late November. The construction of a second
Lifter 4 prototype required 4 days of effort, and was completed
in mid January 2003. This prototype features a more durable
and robust chassis, as well as having an air-gap 7 centimeters
tall (the first prototype was wired with a 5cm air-gap).
The
increased distance of the air-gap on the second prototype
provided a thrust increase when compared to the older model.
The increased distance from the wire to the foil more effectively
transfers kinetic-energy from the emitter to the collector,
thereby providing higher thrust efficiencies.
During
testing in January, it was discovered that creating a bypass
on the output load-resistor of the GRA-50 power-supply effectively
increased thrust. The increase in performance was very noticeable,
and it is believed to be the result of creating a "dynamic
voltage" across the air-gap.
Testing
last summer involved utilizing the conventional power-supply,
which uses resistors to maintain a minimum-voltage. Bypassing
the output load-resistor allowed the voltage to remain steady
across the air-gap at a 'bare-minimum level' to maintain
charge transfer. Therefore, power that would have gone into
producing voltage was instead converted into higher current-levels,
which resulted in much greater charge-transfer from emitter
to collector.
Upward-bowing
of the chassis of the Lifter 4 was unexpected, due to the
structural reinforcements that we added during construction.
The increased thrust is distributed evenly across the Lifter,
but has a normal additive effect on the center of the Lifter
that causes upward bowing in the structure. This bowing
is seen as a tension on the structure of the Lifter and
occurs when the applied power is above 40-watts.
The
amount of thrust generated by a Lifter is partially a function
of its length. For multi-celled Lifter designs, the length
as measured as the combined length of the wire-foil combination
for the all cells in the Lifter. The Lifter 4 measures 4-feet
on each side and contains 16 cells, but the amount of cumulative
length is over 30 feet for both the first and second prototypes.
Force
was measured during testing by the use of a digital-scale
mounted underneath the test-surface and connected to the
Lifter by thread running up through a hole. This experimental
setup was designed to prevent ionization from affecting
the accuracy of the scale's measurements, and appears to
have provided adequate shielding for our purposes. It should
be noted that it is considerably easier to test the Lifter-4
connected to a scale in comparison to smaller prototypes
like the Lifter 1 because of its greater size and increased
stability. Additionally, the higher-thrust provided by the
Lifter 4 reduces the degree of error inherent in all calibrated
measurements.
The Lifter 4 Power-Supply
The
Lifter 4 indoor tests were performed using the Hvolt series
power-supply from Information Unlimited. The critical voltage
required to achieve lift is 17.5 kV -- however, increasing
the voltage correlates with an increase in thrust.
The
Lifter 4 uses slightly more current than the Lifter 3 does
-- when powered by the 100kV Hvolt 100 power supply, the
current draw for the Lifter 4 is between 3.5 and 4 milliamps
-- for the Lifter 3 the current draw is between 2 and 3.5
milliamps.
For
additional information about the Hvolt series power-supplies,
visit the Information Unlimited website. click
here
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