Within the next few years battery powered air-taxis will be available for trips up to 25 miles between vertiports for one or possibly two passengers. How far beyond this distance and payload can safely be flown will depend on battery life. When I mentioned these limitations during the recent SAE Aerotech Conference, a member of the audience asked, “why not use a bigger battery”. The answer is that as all-up weight (AUW) increases, the energy required from the propulsion system increases much faster. Energy from batteries is so low that adding a larger battery could actually reduce the payload. This will limit air-taxing to short low payload flights between the tops of commercial buildings.
Moller International is working with a number of developers of the various hybrid components required for its Skycars®. These include batteries from A123 Battery Systems in Taiwan and Turnigy Power Systems in China, as well as electric motors from Yasa Motors in Great Britain and Emrax Motors in Slovenia. Surprisingly no US company produces these required hybrid components.
Freedom Motors Funding
The picture below shows our recently completed portable engine test dynamometer. This dyno allows the ratio between methane (the key component in natural gas) and CO2 (the primary contaminant) to be varied. Currently we have achieved good combustion at less than 50% methane, which is, by any measure, a success. However, we plan to further quantify the results to determine:
Toxic emissions which are expected to be near zero, by injecting water to prevent formation of nitrious oxides. From various experiences, we know that CO2 and HC emissions are extremely low when using methane (natural gas).
Efficiency of burning sour gas as a function of methane content.
Minimum methane content where combustion is stable, which we expect to be substantially less than 50% based on tests to date.