Below is an excerpt from the Pipistrel newsletter about the Alpha Electro. Sounds totally awesome for flight training. One thing I thought about that they don't mention is high altitude performance. Electric drives don't lose power at high altitudes (~ mostly true..). I'm teaching my daughter out of KMTJ and we couldn't do it with a run-of-the-mill 172 because I'm too heavy. Our typical DA on a summer day is above 8K. So needing a bigger plane costs more in a many ways, acquisition, maintenance, fuel & it takes a longer to learn to fly a 182 than a 152.

I think electric planes are going to change a lot of things. I'd bet that once they get the bugs worked out, engine failures will be as infrequent as turbines (maybe even less). Not much to go wrong with an electric drive train. Plus designers could build in-line twins or even shaft within a shaft counter rotating props (I believe they can create some big efficiencies with this concept).

Imagine how quiet it will be.... A guy could buy some solar panels and drive the variable cost of flying to almost zero.

They say they hope to build sell these for less than 100K euros. If it will fit and haul my big butt around, I'm in!

Lastly, its going to be fun to see what the experimental market does with this. I'd bet they'll come up with some awesome stuff very quickly. Vans RV -E ??

Battery technology just need to get good-enough to get this started. Once it starts is going to just gain momentum and batteries are going to keep getting better once airplanes become possible.

I truly believe this will be the biggest advance in aviation I will see in my lifetime!!


The ALPHA ELECTRO has been nicknamed WATTsUP, and this new 2-seat electric trainer based on the popular Pipistrel ALPHA Trainer airframe took to the skies for its maiden flight last Friday August 22.

Celebrating its 25th anniversary, Pipistrel is unveiling the proof-of-concept WATTsUP 2-seat electric trainer at Salon de Blois airshow, France, this coming weekend on 30-31 August 2014.

WATTsUP was an advanced technology exercise developed in partnership with Siemens AG, who provided the main electric propulsion components and represents the next generation of Pipistrel's electric aircraft.

Every single element of this new aircraft has been refined to be lighter, more efficient and more reliable than anything before.

The 85 kW electric motor weighs only 14kg and is more powerful than the popular Rotax 912 series, typically used on Ultralight and LSA aircraft.

The 17 kWh battery pack is dual-redundant and designed to be either quickly replaceable within minutes or charged in less than one hour, thanks to the next generation of Pipistrel's Battery Management technology.

The airframe uses proven features from hundreds of Pipistrel aircraft flying worldwide.

Performance of the WATTsUP 2-seat electric trainer is personalized for the needs of flight schools.

Short take-off distance, powerful 1000+ fpm climb at MTOW and endurance of one hour plus a 30 minute reserve.

The WATTsUP is optimized for traffic-pattern operations, where 13% of energy is recuperated on every approach, increasing endurance and at the same time enabling short-field landings.

Some other stuff I was thinking about:

No mixture control
Auto throttle and reverse would be easy enough to build
No carb heat
I doubt you'd need cowl flaps
Seems like one gauge to monitor - battery level
Props could be spun much slower - gear boxes (if needed) would be easy without power-pulses)

As much as I hate to rain on this parade there is at least one significant obstacle to a battery powered airplane even if battery technology ever provides sufficient energy density. And that is the inability to "refuel" quickly.

No battery design in existence today can be recharged to full capacity in the time it takes to put an equivalent amount of liquid petroleum into a tank but it's remotely possible that this could become possible at some point in the future. What will likely never become a reality is a means to deliver that amount of electrical energy in a few minutes unless it turns out to be feasible to install a medium capacity nuclear reactor at every airport currently selling avgas.

The electrical equivalent to pumping gasoline at 30 GPM is approximately sixty megawatts. At the highest voltage that is considered "human handleable" (i.e. 600 volts) that would be a mere 100,000 amps and at a more reasonable 240 volts the current would be 250,000 amps. To conduct that much current without significant losses and to keep the heat production under 20 watts/ft each of the two conductors would have to be about four feet in diameter. Even if you can imagine attaching such large conductors to your airplane's battery, the magnetic force generated by the two wires would be several thousand pounds per foot of length. And all this is totally ignoring the weight of the conductors in the airplane necessary to carry this current to the individual cells.

You might think that one plausible alternative would be to swap a discharged battery with one that had already been charged at a more reasonable rate. But if this was a busy airport with 20 "refuelings" equivalent to 50 gallons each per day, the average power consumption would be around 1.5 megawatts (about what 50 residential homes would use on the average).

And the FBO would need to have 20-30 battery packs in their inventory so they better be rather inexpensive which seems unlikely given that with today's battery chemistry that would amount to about one million dollars worth of batteries.

The bottom line is that IMO electric airplanes will never be practical for the majority of aircraft use even if battery energy densities approach the level of fossil fuels.

I almost never do a "quick turn". Always there at least a day. This is a non factor if you ask me.

I almost never do a "quick turn". Always there at least a day. This is a non factor if you ask me.

Let's first clarify "how long to re-charge"?

Let's assume 12hours..... Is that reasonable?

For a long flight I would have no problem landing somewhere cool. Hang around, spend the night, get up the next day and keep going. Still beats the hell out of commercial.

Even in the Pilatus, on long flights, I make sure my fuel stops are fun and interesting. The journey is the destination.

Anything more than an hour is not reasonable to me. I own a plane to cut time from my travel. Currently my plane is about 4x faster than my car on a long X-country. When it gets less than 3x as fast it makes sense to drive instead since I usually need a car anyway when I get there.

Also, people on a business schedule do not stop for fun. One of our local hangar tenants flies his Cirrus 3-4 days per week visiting clients. He may only spend 1-2 hours at each stop and fly 700 miles in a day. Or, he may make a 1500 mile trip in one day which would be impossible in an electric plane.

I own a plane for freedom and not having to deal with TSA. Cutting time is important too but most of that comes from landing at the airport closest to my destination.

Not everyone has the same mission. Almost all my flying is business but it doesn't mean I'm in a mad dash the entire trip.

I think an electric plane with no fuel cost, more power and more performance would definitely sell big even if it had the downsides of 12 hour charge time. Even if it were just trainer planes it would be huge.

When it's available here in the US, I'll buy one. They'll figure out the quick charge here soon, just like with an electric car. For enjoyment flying and or training flying, this is a great airplane.

John, great post!!! I've been watching Pipistrel too. Way too much stagnation with legacy airframes.

I humbly disagree with that post even if you are an aviator, pilot and a pioneer

From the OP -

I would imagine that 1 our charge time is pushing it, but hey that's what the article claims.

Just like a "regular" electric car, there would have to be a change in infrastructure for charging.

I for one am open to anything that could perhaps remotely prove innovative when it comes to aviation.

Electric motors are great. This stuff is cool, and I see a lot of advantages (and challenges too).

I truly love vintage. I also love new. But let's not desire to keep new vintage.

While it might take a while to charge the batteries... no one says that you have to use the same batteries from flight to flight. Think of it like your battery-powered power tools. When the battery dies mid project, you don't stop the project and wait for it to charge, do you? No, you grab another battery and put the old one in the charger.

I own a plane for freedom and not having to deal with TSA. Cutting time is important too but most of that comes from landing at the airport closest to my destination.

Not everyone has the same mission. Almost all my flying is business but it doesn't mean I'm in a mad dash the entire trip.

I think an electric plane with no fuel cost, more power and more performance would definitely sell big even if it had the downsides of 12 hour charge time. Even if it were just trainer planes it would be huge.