Electric Airplanes: The Elusive Promise

I read a quote the other day that said agnostics are just atheists who don't want to be called atheists. Rings true for me, I suppose, but I need to retool the definition away from applying agnosticism to religion and apply it to airplanes. I further will add the word hopeful to my agnosticism and that describes my attitude toward electric airplanes at the moment.

That's what propelled me to interview my KITPLANES colleague Paul Dye for this week's video. I think it's worth 25 minutes of your time to watch. He has just completed an experimental project to install an electric motor in a Xenos motorglider kit. That airplane is otherwise powered by an AeroVee, a Volkswagen conversion, or a couple of other hydrocarbon choices.

As detailed in the video, the motor came from a Zero electric motorcycle, as did the battery and electronics. What got my attention is that Paul told me his initial flight data and some quick reduction suggests that if such a thing were installed in an airplane like my J-3, 30 to 45 minutes of flight would be possible. Really? I have no intention of doing such a conversion, but those numbers are the sweet spot for a Cub, since few of us fly them much longer than that on a typical flight. I wasn't thinking of emissions or cost of operation but of a shard of market potential based on capability.

Unfortunately, reality intrudes for everything electric, including cars, but especially motorcycles and airplanes. When we discussed the numbers for the Zero/Xenos pairing, it looked to me to be the perfect duty cycle. Fly it to say, 3000 feet, pick up some thermals or ridge lift, and have a ball for a few pennies worth of energy. What's not to like? As it always does, endurance—lack of it, that is—tarnishes the momentary joy.

Paul lives in an area unsuitable for soaring, thermaling or otherwise. Typically, a motorglider like Diamond's HK36 or a Stemme S12 could be flown directly to a better area for green air and if that required refueling, no problem. Just land at any airport and top off. But the eXenos lacks the range do that practically, at least out west, and because 220-volt charging current is likely unavailable along the way. It's not available in my hangar, either, for my imaginary eCub. To be fair, this may change in our emerging all-electric future, but it's not there now.

The sailplane pilot's solution to this is quickly detachable wings so the entire airplane can be loaded into one of those long trailers and driven where soaring conditions are good. This is a standard weekend for sailplane pilots. But the Xenos doesn't have quick-detach wings so it's a prisoner of the place where it was built. EAA wanted to display the airplane at AirVenture, but Paul said they’d have to send a tractor trailer to retrieve it.

Still, despite its immediate practicality, the Xenos project is the essence of experimental aviation and is more cutting-edge than the vast majority of projects. I wonder if Zero ever thought anyone would be creative enough to repurpose the guts of its motorcycle for an airplane and therein lies another problem. The company wants nothing to do with supporting it. So when the battery pack finally cycles out, will another be available? It may be a moot point because the airplane may not fly enough to reach that point and, in any case, it can always be converted to a gasoline engine.

The Xenos is by no means the only electric experimental airplane out there, but there aren't a lot just as there aren't a lot of electric LSAs, with Pipistrel leading the market. I’ll pause and define a lot: Pipistrel has trickled enough electric trainers into the world, 17 in 2022, and a few dozen before that, to make a legitimate claim of having fleet experience.

One barrier to experimentation in electric aircraft is the battery systems. Brushless motors—light, powerful ones—are becoming everyday technology, but building a safe, reliable battery pack takes expertise. The battery management systems that dole out the power and oversee charging require careful logic to keep them from overheating or, worst case, igniting. It's nothing like plumbing two tanks to an O-320. The attraction of the Zero powertrain is that they’ve already figured all that out, including the instrumentation.

And speaking of Zero, even though I’m a hopeful agnostic, I’m not a customer for an electric motorcycle. Yet. I like to run around the mountains for 300 miles a day and the Zero won't do that, despite its impressive torque. Same for the Tesla cars. A friend recently chided me for buying a new ICE car instead of a Tesla. But the Tesla was $10,000 more and it won't do the job of trailering my non-electric motorcycle to the mountains in a single day. Lack of range further tanked by towing would make it a full day plus a little change sort of trip. Nonetheless, I’m an admirer of Tesla's cars and the practical technology built into them. They have a meaningful share (about 2 percent) of the automotive market.

I would have said electric airplanes are unlikely to achieve the same. Except—and this surprised me—they already have. Scanning GAMA's figures for airplanes I take to be trainers, I came up with about 450 in 2022. It could be higher or lower because I can't determine how many 172s and Piper Archers are bought for non-training purposes. So if the 450 is a fair guess, Pipistrel's electrics already have 3.7 percent. Given the tenderness and limitations of these aircraft, that's not a bad showing.

Some flight schools are making them work, but it requires too much compromising in how the airplanes can be used to be broadly practical. Yet. And if all this is being done solely in the name of emissions reductions, I think broad use is still over the horizon. What we’re seeing now is early adopter buying. I’ll concede that operating costs may swing in favor of electrics across a narrow band of the training program, but I’m not sure the savings are worth it overall. I remain open-minded.

And also hopeful. I’ve never been one to heap scorn on electric airplanes—or cars or motorcycles—for their considerable shortcomings. I’m just not a buyer yet. We should all be happy to see experimentation and development in electric aviation because for every dozen dead ends, there's a true breakthrough in aircraft propulsion that stumbles us toward an uncertain future. And we should all cheer that.