The weakness of many electrical drones today, is the reduced autonomy of their batteries, which obliges operators to divide their tasks into multiple segments, due to the time needed to change the batteries, at best, or having to wait even longer for them to recharge.
A constraint that could disappear with a prototype micro-turbine presented at the UAV Show, the first European drone event which took place in Bordeaux ( south west France ) between 9th and 11th September. Called Decawatt and designed by ONERA, the French National Bureau of Aerospace Studies and Research, the micro-turbine is, quite simply, the world's smallest.
Olivier Dessornes, « Decawatt » project Leader - ONERA :
"The goal, really, is to provide an alternative, extremely compact energy source solution to batteries required for lengthy periods of operational airborne time.
This system is, a highly miniaturized version, of the conventional type of aircraft engine which we have in aviation today ; that is to say, there is a compressor, a turbine, a combustion chamber, here, with an exhaust outlet here. The turbine produces power, which is in turn used to operate an electrical generator located at this point under the mounting."
Two million times smaller than an A-380 engine, this micro-turbine weighs only 680 grams (1.5 lbs) and delivers constant power of 100W in ambient temperatures down to -50°C (-58°F), enabling applications previously impossible with batteries. All, thanks to a micro-compressor of only 10 mm. (3/8 in.) in diameter.
Olivier Dessornes, « Decawatt » project Leader - ONERA :
"As soon as you activate the system, it provides almost instant power, with no recharge time. All you have to do is change the gas cylinder, which is exactly the same as those used for the well known propane-butane camping gas system. It works as long as one has propane and butane to produce the combustion in the chamber. So there is no recharge time as with batteries.
The other advantage is the system’s light weight compared to batteries. Let me give you an example : if you wanted to fly for four hours with a 1 kw power battery, you would have 20 kg (44 lbs.) of mass. This system, in that situation, would require a slightly larger version for those same four hours, but would weigh only 8 kg. (17.5 lbs.), or less than half in terms of mass."
The result of eight years work, the Decawatt micro-turbine produced its first watts last April. It will still require an additional three to four years’ work before being put into production. Meanwhile, initial contacts expressed interest in this technology during the U.A.V. Show.
