The Ground Support equipment

After lugging laptops, joysticks, helicopters, starting hardware, jumper cables, etc just to try flying the prototypes, we've decided that a field box is required. The dependency on an automobile for high amperage 12V and low amperage 110V power also was a serious setback. All of the commercial, high-end UAVs have cool - ground - stations, so we have to compete with them. Especially this one from GA Tech.

We have taken a much simpler approach and provide the following features:

• Gell-cell 12V battery
• 12V charger
• Power inverter
• Weather-proof 12V outlets
• Posts for 12V "jumper" cables (for starter motor)
• A tool box
• Chargers for the Tx, Rx, glow starter,
• Charger for the 12V battery (from 110 AC)
• Fuel tank
• Starter holder
• Protected, weatherproof switches for all functions

Additionally, we plan to add

• Kill switch
• Ammeter for 12V current draw
• Weather-proof 110 AC outlets
• Fuel pump
• Laptop (iPAQ, Libretto or similar device)

Optionally, it would also have room for the helicopter. This would greatly increase the size of the case for the .60 sized airframe and might be too large. I tried a 36 x 18 x 14 rolling box from the Container Store and found that just the "pod" of the large prototype would fit. The boom was too long, even when detached. The metal attache case that was selected is clearly too small to hold even the LMH prototype, but holds everything else in style. The image on the right shows it in comparison to the large prototype (click to zoom in).

The gel cell battery is required to prevent the electrolyte from leaking and damaging the other hardware. If the box were always oriented correctly, this would not be required. But since it would be nice to have wheels on one end (like a roll behind cart) this is not feasible. One of the easiest solutions is to purchase a "Power Pack" from WalMart/Target/etc. These are self contained jumpstarting solutions for automobiles; they contain a sealed gel cell (AGM actually) battery, a trickle charger and jumper cables. Throw away the jumper cables, remove it from the bogus case and it is a perfect 12V source for the field box.

The inverter does not need to be large; it would really only power the laptop and possibly a small television. Plus a host of wall-wart adapters, but not very much overall current. I've selected a 175 watt (360 peak) unit with no fan; the fan is nice for cooling, but adds quite a bit of noise.

All of the controls and ports should be accesible from the front panel. This will involve drilling some holes in the box, but there really isn't much of a warranty anyway. I haven't found a source for weatherproof safety switches, so cheap ones from RadioShack fill in until a better solution is found.

After another day lost to a poorly charged glowplug ignitor, we decided to switch to a "Power Panel" style device. This did not adapt very well to the briefcase formfactor, so a new case was acquired. The comparison to the old fieldbox is pictured on the left. It also holds the fuel bottle upright, reducing the chance of spills. The weight of the battery is centered in the middle of the case, making it more comfortable to carry.

Parts list:

• Toolbox from Home Depot ($20)
• Power Panel from Hangar 9 ($22)
• Glow-plug ignitor ($5)
• PowerPack from Target ($53)
• 175 Watt inverter from Target ($30)
• Three illuminated switches from RadioShack ($6)
• Binding posts from RadioShack
• Busbar
• 12 gauge wire
• 12V accessory outlet
• Lots of shrinkwrap tubing