The Aerolite EZ-103, according to Dan Johnson’s latest SPLOG column can fly for an hour on four battery packs.
“Assuming a climb to 700 feet above ground and then cruising at 40-45 miles per hour, two battery packs will last about 30 minutes,” wrote Dan. “Four battery packs can be mounted, good for an hour’s flying if lots of climbing to altitude is not involved.”
With the latest news from Bye Aerospace running through my head, that line jumped out at me as I read Dan’s column.
For those who missed it, Bye Aerospace announced on April 22, 2021, “an eight-seat all-electric twin turbo-prop class airplane” it has named the eFlyer 800.
The initial batch of comments on our webite were mostly negative.
“No mention of charge times,” commented Chris. “Pretty useless if its down charging for hours between legs, not to mention a 500 nm range? What a joke.”
“More vaporware. A good way to fleece investors of their $,” claims leo.
AVweb’s comment section on the same story was more of the same, sadly.
But the follow-on comments on General Aviation News give me a bit more hope.
Miami Mike, a frequent website commenter said, “I read a road test report on the new Mustang-e high performance model, it utterly blows the doors off the gasoline version and costs only a little more. Mercedes is bringing out an all-electric top of the line S-class car (EQS), GM is planning on being all-electric in the next few years, as is Honda. These are NOT stupid people, even if you don’t like their cars much. I vote for electric airplanes, and as soon as they become available at competitive prices and performance, I will vote for one with my wallet.”
BJS states, “All this electrification of our modes of transportation is a joke being fostered on us by politicians, but at least one can pull to the side of the road and walk away when the electric car fails,” to which Darrell Hay responds, “Electric motors are much more reliable than gas, diesel, or turbine engines. Not sure why you are thinking it would fail. I have had numerous engine failures in aircraft, lawnmowers, motorcycles and gas cars (due to failed systems and outright structural failure), but never had an electric motor fail to operate given sufficient power and even a modicum of maintenance.”
I’ll be honest, I have no idea if Bye Aerospace will bring the eFlyer 2, let alone the -4 or 800 through certification or not.
Does that make it vaporware? Not if they succeed. And they haven’t yet failed.
When Alan Klapmeier was still with Cirrus Aircraft, I recall him saying that certification isn’t a test, it is a process. If the aircraft maker fulfills the requirements of the regulations, the aircraft will earn certification.
But that process takes a lot of time and a ton of money.
It is true, a 500-nm range isn’t far compared to existing turbo-prop powered aircraft. I forget, how far was Orville and Wilbur’s first flight? Oh yeah, 120 feet.
Four battery packs is good for an hour of flight in the EZ-103. At 40-45 miles per hour, that’s 40-45 miles. While that’s not 500 miles, it sure is farther than 120 feet.
Regarding BJS’s comment about the reliability of electric motors over gasoline engines. I’ve seen plenty of electric motors fail over my lifetime, i.e. washing machine motors, dryer motors, windshield wiper motors, starter motors, etc. and while an aircraft motors design, I would hope, would be far superior to the ones I’ve mentioned, electric motors fail all the time, if not the windings, their bearings fail. But he’s missing the bigger issue with failures, electronic speed controls are also susceptible to failure, even more so than electric motors. They use semiconductors that get very hot and heat is one of the enemies of semiconductors.
JMHO
I am hearing a lot of skepticism. But Pipistrel’s plane (https://www.pipistrel-usa.com/wp-content/uploads/2018/03/Pipistrel-Alpha-ELECTRO-Information-Pack.pdf) is certified and flying now. Sure the range is under 85 nautical miles (60 minutes plus reserve at 85KIAS cruise). But it also only has a 21kWh battery. Payload is almost 400 pounds. “How long does it typically take to charge the batteries with the different chargers? (20%-95% range) 6hrs with 3kW charger, 1h 40′ with 10 kW charger, 1h 5′ with 14 kW, 45 minutes with the 20 kW charger”
Given that 21 kWh costs about $3 vs. $4-5 per gallon for avgas (a cessna152 burns 5.2 gph) you are looking at about a $20 per hour savings in fuel cost. That adds up fast. The battery pack is 53 Kg and swappable (lasts 17 years – 300 to 700 cycles). Battery pack density is about 396 Wh/Kg (21kWh and 53Kg). This density is pretty good, but the batteries Bye is using are reported to be 600 Wh/Kg (https://www.electrive.com/2021/04/21/oxis-energy-readies-to-roll-out-quasi-solid-state-batteries/) and may get up to 700 Wh/Kg by 2023. That means the Pipistrel Alpha Electro could swap in a 53 Kg, 31.8 kWh battery that would be a 50% increase in total charge and a slightly larger increase in range (the reserve would stay the same). The 700 Wh/Kg battery would be a 37.1 kWh battery and more than 70% increase in total charge. Like Miami Mike, I only want to fly about 2 hours before I take a break. This is getting pretty close. I think Bye’s 4 seater, with higher weight limits and flight duration at higher speeds will actually be perfect for me. Fly for 2 hours, pay for a “fueling truck” with a large, high voltage DC battery on board to charge me back up in an hour or so, then back home (for slow charging at the tie down or hanger) or on to my next destination. This is real enough for me. We just need more planes certified and then quick certification of new battery packs as density increases.
Another interesting story. I’ve been watching the development of electric powered aircraft for a while and have high hopes for an electric aircraft in my future. I currently fly a Maule MX7-180C. It is a hugely capable aircraft but I can see a point in my flying future where a lot of that capability will no longer be relevant to my mission. Right now, my Maule is the perfect airplane for camping and flights to bicycling destinations with either my road or my mountain bike. Somewhere off in the distance, I’ll shift back to soaring as my flying focus and an electric motorglider would be ideal for that mission. Only relying on the battery pack for launch and possibly return to the airfield would lower the amp hour requirements and the clean line of a glider would reduce power requirements for overcoming drag. That lowers the bar for a successful electric powerplant. Now I just need one of the Kirkland companies to develop the design!
While the energy density issue will plague electric planes for years, I think electric power may have some hidden benefits. Electric power should allow for cleaner aerodynamics and elimination of cooling drag which should improve efficiency. Electric propulsion should also have an advantage at higher elevations where gas engines loose a significant amount of horsepower. I think most of the current proposed Electric VTOLs are impractical and will simply separate investors from their money, but I am always interested in seeing what people come up with.
gbigs is right, range is determined by bladder capacity, not fuel tank capacity.
Here’s my secret formula for fuel management: Before takeoff, drink about a third of a can of Diet Coke. After a bit more than an hour, I kinda, really sorta need to make a pit stop. That’s a good time to refuel the airplane as well.
YMMV.
Some smart guy developed the ‘jonny jar’ !!
My comments on electrically power aircraft have been from an engineering perspective. not feelings or emotion.
Note the recent statement from the CEO of Textron, from ‘Aviation e-Brief’ ;
” Scott Donnelly, the chief executive of Textron – owner of Beechcraft, Cessna and Bell – has seemingly ruled out the imminent launch of an urban air mobility (UAM) vehicle, stressing that battery technology has not advanced sufficiently to support such an application.”
My previous comments have made 2 points.;
1. The current battery capacity, in watt-hours per pound of weight, is currently 1/23 rd that of avgas, even when accounting for the 3:1 efficiency difference between an electrical power system vs an avgas engine, [ 90% vs 30% ].
The Cessna that I fly caries 50 gallons of avgas and has an endurance of 5+ hours, and a range of 800 miles.
At 114,000 btu per gallon and 3.4 btu per watt-hour, that 50 gallons is equivalent to 1.6 mega-watt hours .Reducing that by a factor of 3 result in 559 kW-hrs of energy.
A Li-ion battery with 559 kW-hrs capacity, today, would weigh 7,686 lb., [ using Tesla 3 data], … which is not a possible solution for a Cessna with a gross weight limit of 2,350 lb.
Even with a 10x improvement in battery energy storage, the battery would weigh 768 lb, vs the 300 lb of avgas ; 468 lb more.
This results in a only 102 lb for pilot and passengers.
2. The other problem is providing the recharging system at the airport, and the time it takes to recharge the battery.
A level 2 charger uses 240 vac at 30 amps for a charge capability of 7.2 kW . It would take 77+ hours to recharge the 559 kwhr battery,
assuming that the airport will provide such a charger. [ my hangar has a 120 vac, 20 amp circuit, 2.4 kW .]
A fast DC charger can provide about 50 kw , which costs about $10k , [ who will pay for this to be installed at an airport?] .
Even with the fast charger, it will take about 11 hours to recharge.
So, I agree with Scott Donnelly .
With current battery technology, you are right. But technology changes. Anyone looking at the Wright Flyer would have laughed at the notion that someday hundreds of people would be carried across oceans in aircraft.
Airbus is exploring the idea of using liquid hydrogen to fuel an electric aircraft via fuel cells. What is revolutionary is their idea to use the cold liquid hydrogen to cool the electrical components down to superconductor temperatures, increasing their efficiency by magnitudes.
In 1903, the Ford runabout had a 2 cylinder, 8 HP engine, while the Wright Flyer was 4 cylinder and 12 HP, more powerful than the existing cars.
Auto development just need better materials and engineering to raise compression and add a Kettering ignition system and a real carburetor.
EV battery technology doesn’t have a clear path to advancements in energy density.
Then, in my 2nd point, the battery needs to be recharged somehow, somewhere.!
Hydrogen..!? It has a lower energy density than the current Li-ion battery.
[ remember the Hindenburg.! ]
Range in a plane without a toilet is an academic question, not a capability question.
I worry more about how the potential spread of electric cars will affect us as pilots and aircraft owners. If electric cars take over and eliminate gas powered cars, I think the big issue for us will be fuel. If oil companies are supplying gas to fewer and fewer cars each year, the price of gas will increase slowly at first and then more dramatically later. Will oil companies continue to refine oil into gasoline only for the aviation and marine industries? If so, at what cost? Could avgas be $10, $20 or more per gallon? It will make it nearly impossible to fly for most and our piston powered planes will become nearly worthless.
Don’t worry about electric cars. There is a lot of problems that are not discussed. (I own a hybrid) and don’t forget to change the batteries.
As mentioned earlier in this pod cast What is a turbo powered
electric power airplane?
It’s not “turbo powered”, it’s “turbine class”, meaning it is intended to serve the same or similar mission that current short haul turbine class aircraft server.