Flight time has been a very vexing problem for most of UAV hobbyists. Generally speaking, the flight time for the high end consumer-level UAV is about 25mins; however, the flight time of UAVs for commercial use is not that long.
Many companies desire longer flight time for their own UAVs and are depressed by a constant replacement and charging for the batteries. Most UAVs are powered by the high-end lipo batteries, also regarded as the low energy density battery. That is to say, as to its voltage, the volume of this battery should not be that big. It is unrealistic get a longer flight time for the UAVs by just adding the batteries packs.
After the research and development, Pegasus has come out with a solution of using gasoline instead of using batteries. This company is now having a beta test for the GE-30RangeExtender system, which is a gas-electric hybrid that can be inserted in the battery terminals for most of the commercial- level UAVs. The flight time for the current UAVs is lengthened to 2 hours owing to this system, and it is possible that this system would be used for the bigger models in the future.
The gasoline can bring more energy than the battery according to energy density. A record from the American Institute of Physics shows that the energy of a car filled with gasoline equals to the energy that a thousand dynamite rods can make, and the energy density of the gasoline is 50 times higher than the UAV battery.
In essence, RangeExtender is the two-stroke internal combustion engine that fits for the UAVs though it is not as easy as it sounds. You can not just install the rotors on the grass trimmer to make it fly, or maybe someone has already done this before. Of course, you can make an UAV that looks like a grass trimmer, but that would be a different story.
RangeExtender is a system of gas-electric hybrid made from Pegasus, which can generate appropriate power to wheels, but it is not equipped with electric engine and gas engine as the hybrid electric. RangeExtender is not just mechanically integrated with the UAV but a micro edition of the power system used by large ships. It converts the energy powered by the gas engine into electric power and provides power for the electric motor to make the propellers work.
A good news is that RangeExtender can be purchased in this late summer. RangeExtender would be used by large commercial UAVs. Till now, Pegasus has not mentioned the price, but it has put forward by the MattMcRoberts that RangeExtender would cost far less than $12000 of an annual expense of the batteries for most of commercial UAV operators.
Pegasus is not the first company who's tried to solve the existing problems for the UAV battery. TopFlightTechnologie from Massachusetts has tried to use generator, powered by gas engine, to charge for the UAV batteries. The hydrogen fuel cell provided by the UK IntelligentEnergy can also extend 2 hours' flight time for the UAVs just as the Pegasus system.
Of course, nobody gets cheered by the gas-powered UAVS besides the operators who use commercial UAVs to survey the petrol pipeline or mine. According to the record of US Energy Information Administration, a gallon of petrol could produce nearly 20 pounds of carbon dioxide. The gasoline, maybe, can not replace the UAV batteries but it is a new step forward towards the UAV flight time issues. Grepow is now achieving great success in UAV batteries, and many UAV pilots are getting impressed by its new smart battery-Tattu battery. You may also take a look at the tattu batteries if you're interested in it.