Why Diamond’s Electric DA40 Could Be A Corner Turner


When Diamond’s presser on its new-OK, planned-electric DA40 arrived yesterday, it almost went into the bit bucket as just another in an ever longer list of e-airplane announcements. But then … wait, this is Diamond, not a garage startup looking for starry-eyed VC dollars. Nonetheless, I have learned to carefully word search press releases for the phrase game changer and/or either word separately. The announcement passed through my filter.

Having been knocked all but senseless by weekly announcements on new electric airplanes, I have nonetheless retained enough of my wits to sense that Diamond’s entry shows promise. I’m not going to call it a game changer, because I don’t think it is, but I would coin a new phrase: corner turner. There’s a favorable alignment of timing, rising demand, advancing battery technology and a cooperative regulatory environment that could very well buoy this project into viability.

When I first started covering electric airplanes more than a decade ago, no one knew what to expect. But industry leader Pipistrel eventually concluded that the best way to build an electric airplane was not to slap an e-motor into an airframe that had a gasoline engine, but to design the airframe clean sheet as an electric. Perversely, it then slapped an electric motor into the Rotax-powered Alpha trainer and enjoyed modest sales success, albeit not in the commercial flight training world. With its eFlyer 2, Bye Aerospace is hewing to the ground-up approach and Diamond is just electrifying a DA40.

There may be method to this madness. First of all, the DA40 is a proven airframe with benign, predictable handling that’s yielded a superb safety record. It hasn’t been every flight school’s cup of tea, but it has still found sales traction. Now, something intriguing: Diamond isn’t certifying a new type here, but doing an STC for a new powerplant. Diamond’s Scott McFadzean told me they hope to be able to retrofit existing airframes with electric propulsion. Think about that. Your gasoline- or diesel-powered DA40 is timed out and three years or five or eight years from now, the electric economics look better, so you convert it. If they can make this work, it would reduce the capital requirement by leveraging sunk costs in an existing airframe.

Some numbers: Diamond says the eDA40’s endurance will be about 90 minutes, with a return-to-service charge time of about 20 minutes. One charging proposal is a truck with a battery pack that could drive right up to the airplane just as a fuel truck does now and to shave costs, the truck could be charged at night to capitalize on off-peak pricing. (I’m sure it will have an onboard computer to figure all that out and send a text reminder to the driver’s Apple watch.)

The batteries will be in a pod under the belly of the airplane and although I don’t have the weight of them precisely, the airplane will retain its 2821-pound gross weight (1280 kg) on a planned empty weight of 2403 pounds (1090 kg). Payload will be about 190 kg or 418 pounds. It’s a two-person airplane, even though the cabin retains its original volume and seats.

Diamond estimates the battery life will be about 2000 cycles, which translates to a best-case of 3000 hours. Real-world performance here matters because battery replacement is expensive and shorter cycle life could chew into the 40 percent lower operating costs Diamond thinks the eDA40 could deliver. And although 40 percent sounds like a lot, it’s not necessarily if a school doesn’t budget that for fuel. No hard numbers on price yet, but McFadzean said a working estimate of $550,000 is realistic. That’s similar to the Jet-A DA40NG.

Heretofore, electric airplanes have been curiosities and somewhat illusory. I’ve had to travel all the way to Slovenia (twice) to fly one and European owners have made themselves scarce when asked about operating economics. But I think a sea change is afoot caused by a combination of worry about unleaded avgas costing more, looming climate change regulation and a sense of inevitability of electric propulsion, given the directionality of the car and truck market. After a period of doldrums, the electric vehicle market is again booming.

While the timing is more favorable for an entry, I have no feel or prediction for the developmental timeline. I don’t see these airplanes being disruptive. Yet. They may eventually get there, but Diamond will have to prove the benefits of electrics over its efficient gasoline and diesel aircraft. Flight schools pinch pennies and while some are sure to be early adopters of an airplane or two, it’s fleet sales from the likes of the University of North Dakotas, the Embry-Riddles and other schools that drive volume and, to a degree, the cachet that leads to additional sales.  

And speaking of UND, I asked the school’s chief instructor, Jeremy Roesler, what the potential might be. He thought 90 minutes of endurance was a little tight for UND’s needs, but perhaps workable. Like everyone else, he expects electrics to outstrip the infrastructure required to support them and that’s likely to yield some turbulence in the acceptance. He sees geography as potential destiny. How will those batteries perform in a North Dakota winter and what will cabin heat do to endurance? He also said something surprising: “I think we would be more likely to have a Jet-A fleet before an electric fleet.” He said the school has been impressed with the longer overhaul times and low operating costs of diesel and is viewing them more favorably.

Diamond owns the aerodiesel market so this may bode well for the company because it’s likely that electrics, when they are accepted, will go into mixed fleets. Operators will continue to need airplanes with longer legs than electric aircraft will be capable of for perhaps the next decade. By 2023, say, Diamond may very well be the only company that can offer the same model with three propulsion systems: gasoline, Jet-A and electric. That’s quite a portfolio.

Although Roesler says UND may not be ready to buy electric airplanes at the moment, he says he’s bullish on Diamond’s chances. And he does consider the eDA40 a game changer. “If there’s a company to get electric airplanes into the industry, Diamond is the one. I have great confidence in Diamond doing this,” he says. That bodes well, too, because while I just flap my lips, Roesler actually signs the checks for new airplanes.

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  1. Turning a corner? Sure… The last time I remember anyone turning a corner it was my mother in-law, right into a fresh pour of concrete. I got a funny feeling that’s where this is going.

    • Hoverboards suck when it comes to wet concrete, right? If she had been in a car, you could have rescued her much quicker. Oh, wait a minute. I see what you mean. Hoverboards are great for mother-in-laws and concrete.

  2. Going the STC route is certainly an interesting approach. It’s inevitable that in the not-too-distant future (20, 50 years?) we will see a majority of new vehicles and light GA aircraft powered by something other than just an internal combustion engine, whether we like it or not. Either the industry works to iron out the issues now so we have somewhat-useful vehicles in the future, or we resist kicking and screaming until the inevitable happens and we have to start the work of adapting only then.

  3. Airplanes are no longer built to be faster, haul more, or be more available. The focus seems to have drifted to other less reasonable and to more ethereal realms.

    • Arthur – I completely agree with your first sentence, but don’t agree with your second. The design goals for many airplane projects today are to make them cheaper to buy and/or cheaper to run and/or easier to fly. These are not unreasonable, ethereal goals.

  4. An objective and well-reasoned view of the potential marketplace—and the problems of fitting a otential product into a that I’ll/defined market

    Most electric manufacturers try to fit a square peg into a round hole (the load and range problem). Saying “your former 4 place or 4 hour airplane is now a two place and 1 1/2 hour airplane” defines the problems with electrics.

    UND is a perfect testing ground for a problem that nobody acknowledges for electric cars or airplanes—cold weather saps the life out of batteries. Minnesota considered an electric auto mandate (“hey, it kinda worked in California!”) but found that cold weather range was even MORE limited—up to 40%—max endurance in this case now becomes under an hour—even LESS if you want to use the cabin heater! And don’t forget that it gets even COLDER with altitude—better dress warm!

    Congrats on the DA-40 for thinking this through (milked the “paper-only” wanna-be’s) and Paul’s objective analysis.

    • “Saying “your former 4 place or 4 hour airplane is now a two place and 1 1/2 hour airplane” defines the problems with electrics.”

      Nailed it!

    • I’ve mentioned this in this forum before but … I’ll retell the story. In Oshkosh, there’s a Tesla Supercharging station. For a long time, I never saw any Tesla’s in there but last year, passing by, I noticed some. So I went over and talked to the folks sitting there waiting for their electronic beasts to fill up on electrons. One guy who LIVED in Oshkosh was extolling the virtues of his car. So I look him square in the eye and ask … “What do you do when it’s -20 deg out?” He looks ME back in the eye and says, “I can work from home.”

      Problem defined !!

  5. Here’s hoping for enough human embryos, still waiting through awkward first dates, that will have an interest in flight to populate the pilot ranks in the future of electric airplanes.

    The only thing that really keeps my attention concerning things that progress at the speed of rust is my ageing. Going for a rich, colorful patina…

  6. Why is it that most of the commenters are so against change? Sniffed too much leaded fuel? Electric aircraft are coming for at least one reason — low operating cost. I drive a Chevy Bolt and it costs less than $0.03 a mile to drive with no scheduled maintenance. The batteries are only getting better. I fully expect that some of the early pioneers will fail but this is going to happen.

    Something to think about — Ford had their electric F-150 on display at Airventure. There is a good reason why

      • Also, Cadillac had maxed out their reservations for the Debut model of their electric Lyriq in only 10 minutes.

    • Everyone should question change! Always test to see if it’s progress or just a really expensive busywork.

      • Actually, everyone should question the status quo. If there’s one thing I’ve learned in my 52 years it’s that 90% of what we were taught about life is fundamentally wrong and change is necessary. Of course most of the nay sayers here are living rent free on the left side of the Dunning-Kruger curve so the idea of embracing change is too painful for them.

        • Question all you want. The one thing I’ve learned in my 65 years is that change is usually in reverse and costs more! Unless it’s “better” then it’s worse.

        • Thank you, Daniel, for making me look up “Dunning-Kruger curve.” This is a scientific way of saying that there is no hindrance to confidently forming and expressing uninformed or ludicrously wrong opinions. I like it!
          I am taking bets on what comes of age first: a massive traffic jam caused by hacked self-driving cars or electric planes able to fly cross-country.

        • As someone correctly stated, “we’re the products of what we’re told and taught, sold and bought.” I’m excited for further development of electric technology as the 100LL I’ve been consuming for the last 40 years is under increasing environmental and economic pressure, not to mention availability.

          I asked the president of Aviat at this summer’s AirVenture if he’s considered electric propulsion for the Husky; he said no. Probably not enough interest to pursue the requisite R&D at this point, but I would snap one up in an instant (even with a payload restriction) for short jaunts to back country fields and win favor from both neighbors and wildlife.

          As with the evolution of the combustion engine, the development of electric propulsion technology WILL advance and WILL become economical. Maybe not in my remaining years, but it’s inevitable for our continued ability to enjoy flight.

    • Resistant to change? No. Resistant to changing to equipment that cannot possibly meet mission profiles? Absolutely.
      My mission profile is a 577 nm trip one way. In a C182 that trip with average winds at 11-12k MSL is 5.4 hrs enroute. Fuel burn is 10.7 gph or about 60 gallons/360 lbs. I have a two day turn around at my destination. Usually the aircraft is lightly loaded, myself and a passenger or solo, but occasionally I bring a load of parts and equipment. My MTOW is 2950# and landing wt is 2800#. So with full fuel and cargo at 2950# I land at 2590# or about 200# below my LW limit. My refuel time is 20 minutes – 30 minutes. My engine output at altitude is about 63% of the base 230 hp. Neglecting the take off power and climb power consumptions (16-17 gph take off and 13 gph cruise climb through 5000 ft), My mission requires 765 kW, plus 1 hour reserve + 45 minute alternate (personal minimums) if flying IFR. Temps at 12k range from 15C to -25C. I use the cockpit heater.

      GM just announced a new “game changer battery” which will compete with Tesla’s battery. At 200 kWh it is described as “massive.” No one talks about the weight of these batteries, but the battery in my ancient laptop is the heaviest component of the laptop. So, with the most massive (and not yet produced) battery, my mission profile will change from non-stop to 5 stops, a minimum of 1-2 hours for refueling/recharging (@ 800V), a loss of cargo capacity, and turn my 5.3-5.5 hour trip into 15 hours making it far cheaper to drive the 13 hours. (14 with Chicago traffic). Not to mention with GM’s record, I’d need to build a ramp to park my airplane by itself and hope it doesn’t incinerate itself. And not a soul is talking about how much these batteries weigh and that weight doesn’t measurably change with a full charge, leaving you with a MLW limitation that is fixed, where with gasoline If I need to haul a few hundred extra pounds of cargo/passengers, I can reduce my range and make one fuel stop costing 45 minutes.

      It is the mission profile and economy that matters, not the propulsion system. Give me that efficiency/flexibility, along with a warm cabin and anti-icing, I’ll buy in tomorrow. but not until then which won’t happen in my lifetime without a major breakthrough in battery chemistry and physics. Then you have to build a power plant to charge the things. Figure another 70 years before we see it in any practical way.

      • Your response is the MOST poignant, Art. Airplanes are just high tech tools to transport people … for their most important use. If they can’t get you someplace faster or easier, they don’t justify their costs. An electric airplane is nothing more than “feel good” material for the tree hugger crowd at this time. It is NOT REALISTIC given today’s battery energy density capabilities.

  7. I still believe the ‘Corner Turner’ is the Turbine-Electric Hybrid (TEH) Helicopter conversions. The electric motors replace both the main rotor transmission and the tail rotor drive system. Weight is more of a trade off and the battery pack only needs about 15 minutes of take-off/hover boost. The TEH will charge the booster batteries during the flight.

    Using a Turbine-Electric Hybrid Helicopter between warehouse roof tops could eliminate thousands of Over The Road (OTR) trucks. The noise is less a problem around industrial parks and most of the helicopter technology is FAA approved already.

    The best part about TEH, they don’t need to shut down during turn-arounds. Greatly reducing cycles and the complications inherent with battery starting turbine engines.

  8. “Better batteries” have been “just around the corner” for years—but are still not viable.

    There MAY be a future for an “electric ultralight” (but it hasn’t happened yet)—the electric ultralight only holds the pilot—it cruises slowly—the structure can support batteries—and it is usually flown low and slow—for under an hour and not for long distances.

    Comparisons to electric cars hold no weight—Eva don’t have to lug the weight aloft.

    IF there is a future for electrics, I would like to see a hybrid—a small conventional engine driving both a propeller and a generator that would drive an electric motor as well as charging the battery.

    Good fuel consumption—no need for huge battery weight load—good weight/power ratio for takeoff, twin engine power redundancy, and fast turnaround time.

    A Skymaster would be a good test bed (no thrust asymmetry)—it could almost lug a Prius engine and battery aloft, as well as a payload.

  9. I really don’t understand the difficulty with electrics. If it’s a weight issue, get skinnier friends. If it’s a limited range issue, move all the airports closer together. We humans are very adaptable and flexible. If a 4-place will only fit 2 after conversion, either don’t allow new Catholics on board, or take out the seats and use yoga mats. Sheesh, these “Problems” are soooo easily solved!

  10. Not to forget the DA-40 comes from the same country as the first electric airplane ever, and that was in the early 1970s. Look up Militky-Brditschka….

    3000 hours with 90′ endurance and 2000 cycles seems a bit stretched even without heating, you’d have to use up every little milliamp in that battery on every flight before recharging. If the 20′ recharge time holds it might still work for training missions. The “battery on a truck” system seems a bit problematic, the truck would need to recharge while the aircraft is in the air, thus having double the battery lifetime issues and effectively requiring two batteries.

    • Recharging from batteries on a truck doesn’t work. Not only does the truck have to be recharged, but the truck is tied up while charging a plane–even at 20minutes for recharge, the truck and driver couldn’t service 3 planes an hour. Better to have fixed recharging stations. Then there is the cost of the truck itself–hard to amortize over a few airplanes. Paying for the extra equipment and personnel more than offsets any savings on using electrics on a small airplane.

  11. I’m just a fair-weather, VFR pilot/owner of an old C172. I love the idea of an electric motor, they are powerful, light, reliable, proven. I just have qualms about battery plants with the current technologies, in cars as well but even more so in planes. Fuel in planes at least burns off the weight penalty in flight, but batteries weigh the same empty or full. Maybe some newer technology will change my mind (solid-state, etc.) but I don’t know. Still, the charging times, temperature variations, etc. I think something like a hydrogen fuel cell configuration would be best, of course with safety concerns fully tested and addressed. That would be scalable up to airliners. Gotta pack a heck of a lot of AA Batteries in a 737!

  12. One thing a lot of commentators here seem to be ignoring is that in the early days of aviation, no aircraft of the time could compete with the capabilities of even a lowly 152. We are at a similar point with electrified aviation today. It will take time for it to catch up to conventional aviation, but you have to start somewhere. If emerging technologies ceased development every time someone said “it can’t be done”, we never would have landed on the moon – it was a physically impossible task in the 40s and 50s until several important breakthroughs were made.

    • The thing is, Gary, there is no defensible reason to engage in a crusade to build coal-fired airplanes. We actually HAVE Cessna 152s.

      • Only because progress was made in advancing aircraft technology when everyone at the time said it can’t be done, which was my entire point.

  13. There is no way to get a cycle life of 2,000 if you charge in 20 minutes. A realistic number is more like 600. If you use the correct onboard charging system – the cycle life could be endless. There has never been a battery made that likes to be recharged. That’s why we still use the alternator in our cars.

    • No one has yet mentioned anything about airplanes that turn themselves into hangar queens … for various different reasons. Just imagine one of those electric airplanes that sits for — say — six months in a hangar during the winter time. I’m sure that will shorten the life cycle of the batteries.

      • Only if left at full charge. There is a recommended storage charge. Cold and heat usually causes problems when in use. Fast charging and fast discharging are the big enemies of cycle life. We offer solar charging, a wall charger for storage and another for full charging and then of course the lightweight onboard charger for flight. The small battery is only a buffer, plus for emergency backup and takeoff assist.

  14. Nobody is saying that private enterprise shouldn’t TRY to build a practical electric airplane. Let them TRY to go through the certification process. Let them TRY raise capital. Good luck to them IF they get through it.

    The marketplace is the ultimate arbitrator on the worth of a product. If these purveyors of dream planes succeed in developing, certifying, and marketing their ideas–they’ll be rich. If not, the concept will die a natural death.

    If there was money to be made in the concept–the large aerospace companies would be doing it already–I don’t see any of the manufacturers of today’s large and small aircraft investing a lot of their own money in the concept. Similarly, if there was a lot of money in it, the “Billionaire Boys” in the space industry would be active in the market–they’re not.

    Electric motors and batteries are not new. This isn’t a new concept–it’s been talked about for years. This isn’t a technology-enabled concept–made possible by breakthrough technology. It’s more akin to “bar talk”–“Somebody oughta build an electric airplane, they would sell a million of them…..” (sound of crickets chirping….)

  15. So the commercial pilot wannabe walks into the Chief Pilots office with his brand new commercial pilot license from the school with electric trainers.

    The CP looks at the kids resume for 11 seconds and then says “Sorry kid we can’t hire you, you don’t have any piston time”….

  16. Ain’t happening anytime soon on any scale other than a fringe minority buying these things (most likely large government subsidized flight schools maybe).

  17. A game changer would be if the eDA40 has wings that will rotate to lengthwise. Similar to some of the flying car concepts out there. But, in my opinion, no need to make the eDA40 into a flying car. Just develop the folding wing technology because it would have the following advantages:
    1 – More practical for storage at FBO.
    2 – Easier to put into a trailer to carry across country.
    3 – Easier to ship fully assembled eDA40 in containers to any place on earth.

    Without the folding wings, Diamond opens itself up to someone else doing so and thereby taking flight training market share from them.

    Also, I think a trainer plane really needs more like 2 hours of flight time.