|The M1A1 Abrams uses a Honeywell AGT1500 gas turbine engine |
|Robinson Helicopter Co. R66 gas turbine |
|Solar Turbines, GS-350, 225 kW generator set |
Note: the generator is bigger than the turbine!
The first question that needs to be answered is, what are the size and weight constraints that the design of our robot harvester/tender puts on a possible choice for its power source? We can get these design constraints by remembering that every design problem always brings with it its own size and weight scales. So as long as the size and weight of our 'bot's power source is less that 5-10% of its overall size and weight, there is going to be no marginal benefit to making it smaller.
The target size and weight for our 'bot, that we estimated previously, was on the order of 6-8 ft long and less than 300-400 lbs. This puts a size limit of 1-2 cubic-ft and 10-20 lbs on our 1-2 kW power source.
Here is a 1.3 HP gas engine from Honda that fits our design constraints easily.
|Honda GX35, commercial lawn and garden engine |
Compared with a small gas turbine from BladonJets that also fits our design constraints.
|Bladon Jets, Micro Gas Turbine Engine |
And just for comparison, here are a few spec's for a comparable reformed methanol fuel cell.
UltraCell's XX55: 50 W, 3.5 lb, 12.3" 3.2" 8.6" l/w/h
 M1A1 AGT1500 spec's
 Robinson Helicopter Co. R66's spec's
 Solar Turbines
 GX35 spec's: 1.0 kW, 7.6 lb, 8" 9.2" 9.4" l/w/h
 Bladon Jets