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- FIRST PRACTICAL HYBRID AIRCRAFT TAKES TO THE SKIES — AND COULD SAVE MANY LIVES
First practical hybrid aircraft takes to the skies — and could save many lives
- By John Hewitt on July 29, 2015 at 1:00 pm
- 7 Comments
Spanish firm Axter Aerospace has developed a new hybrid powerplant for small single engine planes. This thing just makes sense. Its purpose isn’t to save fuel, carbon, or the planet. It’s designed to save lives — your life, and anyone below.
Light aircraft aren’t just dangerous for movie stars and other famous people who might casually pilot them without taking proper precautions. These planes kill many folks each year who seemingly do everything right. Engine stalls at unfortunate altitudes, or blown gaskets at any altitude, are one-way tickets into the hayfield — or worse. The solution, one which may soon no longer be any more optional than seat belts, is Axter’s hybrid electric add-on.
The accessory electric motor nestles in neatly between your standard Rotax 912 or 914 jet fuel engine, and the prop. When the pilot flicks a switch, it dumps 30 kw (approximately 40 hp) of pure rotating bliss into the power pipeline. While the device can be used for fuel-free taxiing on the ground, or as a welcome assist for short and weighty take-offs, its real purpose is to buy time in the air when the engine conks.
In tests on a light aircraft, the electric motor alone enabled it to climb at a rate of 200 ft/min and stay in the air an additional seven minutes. That seven minutes in the air may not always be enough time to get to where you want, but it should be enough time to get where you need.
The system is already certified for flight in Spain and available in kit form. As would be expected, its lithium battery charges from the main powerplant. Since it is more of a peripheral than an integral component built together with the engine from the ground up, you probably want to hang on to the original starter motor that came with your plane. That’s a shame, because if sufficient low RPM torque could be extracted from the Axter motor without unduly stressing it, the system as a whole could be simplified. Presumably, the motor does not add significantly to shaft friction or inertia when not called upon.
The exact design of the motor is not completely clear, although some of the most efficient motors in terms of weight-to-power are the so-called outrunners. Generally, the shell of the outrunner spins around the windings (like a CD-ROM), which for E-planes translates into more torque and lower RPM than its inrunner counterpart made from the same copper. That puts you in the range for a direct drive mount to the prop, eliminate bulky and typically draggy reduction drives.
Three-phase brushless outrunner designs have already become established as the primary powerplant in the paramotor business. For example, a unit available from BlackHawk puts out an impressive 14 hp with a motor that astoundingly weighs just a few pounds. When mated to a conveniently foldable and streamlined prop, it can deliver 120 pounds of thrust. Anyone who wants to experiment with this system can pick one up now for under $10,000. As you can see from the picture above, provided your neck muscles are strong enough, you could practically mount the entire system on a helmet.
With the first successful channel crossing taking place just days ago, the light craft aviation business has now seen its future — and that future has electric in it. Real jet fuel engines will always be around for the serious and dedicated missions (it’s just physics my friends, get used to it), but hybrids like the Axter will undoubtedly help ferry the machine-risk-averse into the air.
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