The big issue here is whether or how to multiplex various high and low bandwidth data streams.
Some assumptions can be made-
Current cam of choice is the PC-17 Color Microvideo Camera available thru Supercircuits. Its a 2.5 ounce, 450 line, 2"cube.
Supercircuits also offers a transmitter suitable for initial flights, the 915 MHz ATV-900 (is this the model that Otto says suffers from the lack of a sync pulse stretcher?).
A cellular phone may end up being the default vox link, with potential avionic telemetry and control data use.
===included comment from Mark C. Otto=== I have recently designed a telemetry system for use on my R/C airplanes that uses a 68HC11 and SuperCircuits ATV transmitter. The audio channel is driven by a modem chip off the HC11's serial port so I get full motion video and 1200 baud data on the audio. A modem on the audio output of the TV receiver feeds my HP palmtop with the data at RS232 levels and the palmtop stores it on flash disk. My only regret is that I didn't go with PC electronics for my transmitter - the lack of a sync pulse stretcher on the SuperCircuits transmitter prevents sufficient sync signal integrity to drive a VCR from the recovered video. +==oOo===+
GPS- Provides superior positioning info for "over the horizon" work. Can be integrated to GIS, etc.
Flux Gate Compass- Backs up GPS and provides pointing info if blimp is crabbing or yawing in place.
Two axis inclinometer- Provides attitude info in aerobatics.
Thermistor- temperature reading.
2-3 sq. meters of solar film or cells could generate about 100 watts of noonday power for endurance missions. Amorphous solar films in on-hand catalogs are rather heavy for their power density. Crystalline cells are fragile, expensive, and laborious to install. Better solutions are sought.
===included message excerpt from David Beck=== Perhaps there is a way that the shape of the blimp could be adapted to focus the sun on an array in the center of the blimp . That is, perhaps the part facing up would be clear, and the lower part would be reflective. In the center of your tube, you could suspend an array at the focus point. This would keep the array weight down, yet still generate lots of power. Also it would protect the array, and with the money saved on buying lots of cells, you could buy a few more efficient cells. You'd generate a lot of heat at that point, so you don't want to collect too much sun, but on the other hand, the heat generated could be used to generate additional lift - so may be you'd want a series of tubes, and make a structure kind of like an inflatable mat. ===end included message=== Comment- The idea of a suspended solar array under a transparent envelope window may allow for optimal tilting to solar incidence independent of the airship's roll axis. The reflective trough idea is appealing as a means of minimizing cell count. Suspending a reflective sheet in the bag would result in a near optimal catenary shape. Unfortunately the lower refractive index of lifting gas means it can't be used as a focusing lense in a convex profile.
As an inexpensive start, two Graupner 600 motors with 3/1 reduction gears and between and 12 inch props are being used.
A reduction gear and large prop operate more efficiently at low speeds and high altitudes than a small prop with no reduction gear.
The latest mainstream battery technology affordable by the project will be utilized, although Ni-cads are operationally acceptable for some missions.
An open question is whether new battery types, such as lithium ion, output the high currents possible with ni-cads. If not, a hybrid battery system with a ni-cad "sprint" pack may be the best trade off of weight and transient performance.
2 tail servos 2 gear motors w/ props (see above) 2 motor speed controllers with reverse 1 eight channel radio 1 eight channel receiver 1 Motor battery pack 1 Radio/servo battery pack
-The roller-keel serves several functions. It has a wheel for rolling along on smooth ground. It is a float for floating and skimming along smooth water. The ballast and baloonet system is housed within. Drop ballast provides most, but not all of the airships pendulum stability. (7/14/96)
Thanks for flying PolyCosmos. Join us anytime.
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