Watts up

Each one educates and challenges me in a different way. I recently added number 364 to my list of types flown by checking out in the Slovenian Pipistrel Velis Electro, the world’s first certified electric airplane. The one I flew is a rental aircraft at Proteus, a flight school at Santa Monica Airport (SMO) in Southern California.

My instructor, Luke Ferrene, pointed out that preflighting the two-seat trainer is different than preflighting a combustion airplane. Because the powerplant—a 57.6 kilowatt (77 horsepower) electric motor—has no compression, you can spin the propeller with a fingertip. It feels weird.

You wouldn’t know by looking at it, but the Velis Electro is a multiengine airplane. Well, sort of. The airplane has two lithium batteries that supply power, one in front of the cockpit and the other behind to provide the desired center of gravity. Speaking of CG, because there is no fuel to burn and no baggage compartment, the airplane is always in balance and gross weight obviously never changes in flight.

If one battery fails, however, the airplane can still be flown on the other, albeit with reduced performance and endurance. The good news is that you wouldn’t have to shove a rudder pedal to maintain heading as is required when an engine fails on a conventional twin. Thankfully, the FAA does not require Velis Electro pilots to have a multiengine rating. One wonders, though, if a “single motor land” rating will eventually be required.

A more serious emergency would be a battery or motor fire, which is why the batteries and motor are liquid cooled with a 50-50 mixture of water and glycol. Further, the coolant is air-cooled, much like that of a P–51 Mustang, but that’s where the similarity ends.

Starting the Electro is simple, a little more complicated than flicking on a ceiling fan and just as quiet. There is no runup, of course, so all items on the before-takeoff checklist can be accomplished while still parked.

The Velis Electro’s power gauges explain how the airplane is operated. The most important one is the state-of-charge gauge. It is loosely analogous to a fuel gauge and indicates how much charge the batteries have remaining as the flight progresses. If the batteries are fully charged, maximum flight endurance is about 50 minutes plus a 10-minute reserve. With so little endurance, the airplane can be used for little more than practicing maneuvers near the airport. Cross-country flights are obviously impossible. If you do land at another airport, though, be sure that a battery charger is available there. Charging can take up to two hours. Instrument and night flying are prohibited.

Takeoff is not allowed unless the batteries have at least a 50-percent charge, and it is recommended that you are in the vicinity of an airport when the batteries have less than a 30-percent charge remaining. A go-around should not be attempted with less than a 15-percent charge.

The power gauge indicates battery output in kilowatts, and the tachometer is self-explanatory. A digital indicator shows flight time remaining, and this is based on current power output.

As expected, the airplane is relatively quiet and smooth, although I did miss the sound and feel of pounding pistons. The Velis Electro, however, is not quite as quiet as I had expected because of propeller noise. It does get very quiet, of course, with the throttle—or rheostat—fully retarded. When the propeller is windmilling, the motor becomes a generator and charges the batteries, although not much and obviously not for long.

The 90-knot airplane has a glide ratio of 15:1, which is much better than most lightplanes, so getting down during a 60-knot approach to landing requires the use of flaps—which are actually flaperons, combining the functions of flaps and ailerons. After landing, I realized that very little trim change had been needed throughout the flight.

One would expect an airplane that doesn’t use avgas to be economical and rent for less than one that does. Proteus, however, charges the same for the Velis Electro as it does for a Cessna 152. One reason might be that it costs $30 to charge the batteries—in California.

It is easy to question the practical value of an airplane with such limited performance, range, and endurance (unless it comes equipped with a really long extension cord). The answer is reminiscent of when Benjamin Franklin was in Paris in 1783 and witnessed the world’s first manned flight in a hot-air balloon. A fellow observer asked him skeptically, “But what’s the use of the thing?” Franklin replied wisely, “What’s the use of a newborn baby?”

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