Sun Flyer - All electric airplane

I just hope that’s not it’s actual climb rate and they purposefully kept it low for the cameras.

That thing chewed up a lot of that 10,000 runway and didn’t go up real well. And we’re not hitting 70s consistently here yet, let alone 80s.

Granted I’m assuming if you’re building prototypes here you’re building them to perform at least moderately well at this altitude, but perhaps it will be like a lot of things, and better off flying them nearer to sea level.

Lots of nice experimental and other LSA designs you just won’t ever get me convinced to teach in at this altitude. Even the poor old venerable C-150/152 which I really liked flying when I was just starting out was marginal at best for only half of the year here. The rest of the summer it was not a great idea to fly them.

And I don’t weigh what I weighed when I soloed in one. :)
 
dell30rb said:
I don’t think electric aircraft are as affected by density altitude. You don’t lose any engine power.
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The air is still thinner at higher density altitude, so aerodynamic issues still change. The wing and propeller still encounter fewer air molecules with which to interact.


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jimhorner said:
The air is still thinner at higher density altitude, so aerodynamic issues still change. The wing and propeller still encounter fewer air molecules with which to interact.


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Of course, but it will be putting out full rated HP unlike normally aspirated aircraft. Basically it’s like having a turbocharged airplane which is much preferred.
 
You don't hot dog a plane on it's first flight. It's not conducive to becoming an "old" pilot.
Nick Otterback builds great airplanes. I've flown the LS-1 Lightning, and I'd own one in a heartbeat.
 
dell30rb said:
Of course, but it will be putting out full rated HP unlike normally aspirated aircraft. Basically it’s like having a turbocharged airplane which is much preferred.
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Yes, but the issue is not engine power, it is lift. Hotter air is thinner (fewer molecules per volume), which means that as the wings got through the air, there are fewer molecules to hit and force downward. When molecules move downward, Newton's 3rd law tells us there must be an equal an opposite force pushing upward on the wings - lift. Fewer molecules means less lift.
 
If you look at performance tables for a takeoff at say 8000ft between a normally aspirated airplane and the same airframe with a turbocharged engine you may be surprised.

You are correct that Density altitude does affect lift, you’ll need to achieve a higher ground speed in order to get the indicated airspeed necessary to take off. But there will not be any extra drag to inhibit you from reaching that indicated airspeed (other than rolling resistance from the tires)
 
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Electric airplanes and hybrids are on the way not practical for cross country,but should fit into the training market,initially.
 
Shepherd said:
You don't hot dog a plane on it's first flight. It's not conducive to becoming an "old" pilot.
Nick Otterback builds great airplanes. I've flown the LS-1 Lightning, and I'd own one in a heartbeat.
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Good point. I forgot it was a first flight. I wasn’t expecting “hot dog” anyway though, just Vy. :)
 
frfly172 said:
Electric airplanes and hybrids are on the way not practical for cross country,but should fit into the training market,initially.
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I'm big into electric cars, and I think I'd really like an electric airplane, if the infrastructure were there. The reliability is SO much better, since you have WAY fewer moving parts. Imagine if you didn't have to worry about engine overhauls, mag overhauls/timing, stuck/burned valves, oil changes, balancing/clogged fuel injectors, fuel pumps/filters/tank reseals, air filters, exhaust cracks/leaks... There are so many things that we spend tons of money on maintaining on our airplanes that are related to the primitive internal combustion engines we use!

However - The infrastructure is key. It's one thing to make an electric trainer, and I think this is a great proof of concept. However, to get to the point where this is practical for the types of airplanes many of us own (think C182/Bonanza/Cirrus/Mooney/etc), there will need to be a reasonably large network of airports with fast charging stations available, and they're going to have to be FAST - At a minimum, they would have to provide at least the next three hours' endurance in a half hour or less.

The other difference between cars and airplanes is that, aside from flights in the pattern, airplanes generally get "highway miles" on the engine, that is, they're operated at a constant power setting for long periods of time. The biggest advantage of electric cars is in more stop-and-go driving, when they can regenerate some energy into the battery.

I think that in the interim, Pipistrel's hybrid version of the Panthera is an interesting idea. Rather than have a 200-hp Lycontisaur engine that you run at 100% for a few minutes in the climb and 65% the rest of the time, you could have a 100-hp Rotax 914 type engine that runs full bore from startup to shutdown. During taxi, descent, and other operations where you're normally operating at less than 50% power, it would charge up the batteries, and then during takeoff and climb you would combine gas and electric power to get your 200hp for the climb. When you reached cruise altitude and speed, you'd operate solely off the Rotax, and when you began the descent you'd begin charging the batteries again. I'll be interesting to see how Pipistrel does with this concept.
 
One of my biggest worries about the future of GA is that electric cars will collapse the oil industry, and they won't be making anything even resembling 100LL or gasoline any more. Once you've driven an electric car, it's awfully hard to go back. By 2030, I think most new passenger cars will be fully electric, and by 2040 likely most of the bigger vehicles will be electrified as well. There may still be some market for diesel for heavy equipment, and I doubt we will have figured out electric jetliners by then, but those burn diesel and kerosene, not gasoline.

I guess there will be enough classic cars out there still burning gasoline that it won't become completely unavailable, but I think by 2080 or so any gasoline will be a specialty fuel and somewhat difficult to obtain.
 
Yea I'd take the reliability of an electric motor any day....
 
A few more thoughts on fully electric airplanes vs. electric cars:

One of the big advantages of electric cars is the ability to use regenerative braking, and this will be ineffective on airplanes, and also unnecessary because we're converting some of our energy into potential energy which we spend on the way back down to the ground. That may make for a simpler control system for the motor and battery, but airplanes will need relatively larger batteries because of it.

I think the sweet spot for airplanes is going to be a 5-hour battery endurance. While we may not need quite as much of a reserve of battery power as we do fuel reserve since we don't have to worry about things like bank angles and turbulence unporting the fuel when it gets low, getting really low with lithium batteries is very bad for them. There should probably be a method of integrating the battery system with the rest of the avionics on electric planes similar to fuel totalizers being hooked up to GPS right now so that you know how much reserve you're going to have, because while the prop won't stop instantly when the battery is empty, and they'll probably build in some sort of "turtle mode" the way they do with electric cars (think maintainting altitude at Vg for 15 minutes or somesuch), you still have limited power and will get into situations where options are limited.

In addition, batteries don't charge as fast when they get to full - So my suggestion that we'll need five hours' endurance total means that we'll have 1 hour for shooting approaches/reserve, 3 hours for en route flight, and that last hour is likely to remain empty unless you wait for the extra charge. So, get down to one hour (maybe minus approach time), or even a half hour, and then you are on the ground and charge the 5-hour battery to 80% in 30 minutes while you pee or get food, and you have 3-3.5 hours for your next leg.

We are a LONG way off from battery technology being good enough to do this in a cross country airplane. Using my own airplane as an example, let's see what it would look like if electrified. I have a Mooney Ovation, and it runs a nice 170 knots on 12 gph running the 280hp engine at 65% (182hp). Figuring 100% power for the first 15 minutes, 65% power for 4 hours, and a reserve of 50% power for 30 minutes. The climb would thus be 52 kWh, cruise would be 543 kWh, and reserve would be another 52 kWh - And that's power delivered to the prop, so we'd need an extra 10% or so to account for the motor efficiency. That means a total of about 715kWh battery capacity. For reference, the largest Tesla packs in production right now are only 100kWh, the next-gen Tesla Roadster will have 200kWh, and the Tesla Semi will have 1000kWh. The energy density of the current Tesla Model 3, which is pretty much the state of the art for large lithium packs, is 167.7 Wh/kg, meaning our 715kWh battery pack will weigh 9,400 pounds! So, clearly we're going to need a breakthrough in battery/supercapacitor technology before this is at all practical for cross country airplanes in their current form.
 
frfly172 said:
Electric airplanes and hybrids are on the way not practical for cross country,but should fit into the training market,initially.
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I saw a presentation by SunFlyer a number of years ago, and they were upfront in saying their initial market was training, since the range of the airplanes was limited.
 
Everskyward said:
I saw a presentation by SunFlyer a number of years ago, and they were upfront in saying their initial market was training, since the range of the airplanes was limited.
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I wonder how many training flights can be flown in a day.
 
Until there's a paradigm shift in battery tech, it won't likely be useful for much more than two hours of endurance per charge. It's not going to affect GA too much at this point. Don't get me wrong, I love the idea behind it, and hope it happens, but it's unlikely. Electric autos are one thing when weight is of lesser consideration and range concerns can be offset by larger/heavier batteries. Weight is the primary consideration in aircraft, so until they find a way to get 3hrs+ total reserve while maintaining the same payload as its dino-burning equivalent, it's not that useful.

The other side of this whole "electric car" movement is that the electric grid is not up to the task of having every single home charging one to two electric vehicles in their garage every night, not to mention apartment complexes full of charging vehicles. There will be a pain point in there somewhere without significant infrastructure upgrades.
 
As long as the batteries don't blow up.
 
Flying out of APA I’ll be listening for them to declare the emergency when they’re told to extend their downwind and they’re number 12 for landing. LOL.

Oh I’m kidding of course. That’s mean. But anyway...

And then the real fun starts...

“Say fuel and souls on board...”

Zero fuel... :)
 
I'm currently adding auxiliary tanks to my 182. That seems like it might be a bigger deal to manage with an electric airplane.

You can't juggle fuel vs payload either. You're at full fuel weight all the time, every time.

Once battery tech gets light, and can give me my 10 hours endurance, I'm all in!
 
SoonerAviator said:
The other side of this whole "electric car" movement is that the electric grid is not up to the task of having every single home charging one to two electric vehicles in their garage every night, not to mention apartment complexes full of charging vehicles. There will be a pain point in there somewhere without significant infrastructure upgrades.
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I've always thought that it's silly that we all charge electric cars at home. Ideally, electric cars should be charged wherever they sit for long periods during the day, so that they can use energy from local solar rather than taxing the distribution grid. In fact, if there were solar-only charging stations wired to provide the right DC voltage, maybe we could get away without pushing the juice through an inverter and then rectifying it back to DC and the inefficiencies inherent in those processes.

denverpilot said:
“Say fuel and souls on board...”

Zero fuel... :)
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That could be quite a safety advantage... Though damage to batteries can also be dangerous, it doesn't result in the instant fireball that a gas tank breach can. While Lithium is nasty stuff and the fires do result in being very hot, they generally happen fast enough for occupants to exit safely, and they don't happen nearly as often as gasoline fires in cars either.
 
Nice to see this up in the air, maybe my retirement plane will be electric.
 
flyingcheesehead said:
That could be quite a safety advantage... Though damage to batteries can also be dangerous, it doesn't result in the instant fireball that a gas tank breach can. While Lithium is nasty stuff and the fires do result in being very hot, they generally happen fast enough for occupants to exit safely, and they don't happen nearly as often as gasoline fires in cars either.
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The danger probably lies more on the crash rescue team than the occupants. Energized airframe components while you’re trying to dig injured people out of the crumpled metal. Of course, most of these are composite structures now, so that helps.
 
denverpilot said:
The danger probably lies more on the crash rescue team than the occupants. Energized airframe components while you’re trying to dig injured people out of the crumpled metal. Of course, most of these are composite structures now, so that helps.
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Jettison-able battery pack? lol.
 
denverpilot said:
The danger probably lies more on the crash rescue team than the occupants. Energized airframe components while you’re trying to dig injured people out of the crumpled metal. Of course, most of these are composite structures now, so that helps.
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This represents a "training opportunity" for local first responders, like Cirrus does with the chute rocket setup. Most electric cars have a disconnect and/or a spot that you can cut so as to disconnect the battery. The disconnects also generally "split" the battery into multiple "pieces" such that the voltages aren't high enough to cause harm to humans any more.

Think of it like main and aux fuel tanks, except they're all the same size. While most electric car batteries are in the 400V range, if you run it as 8 separate 50V batteries, a single one isn't particularly dangerous. Run the wires all up to a disconnect in front of the firewall before you combine the voltages (series) and once you pull that disconnect, there's no more dangerous voltage.
 
flyingcheesehead said:
This represents a "training opportunity" for local first responders, like Cirrus does with the chute rocket setup. Most electric cars have a disconnect and/or a spot that you can cut so as to disconnect the battery. The disconnects also generally "split" the battery into multiple "pieces" such that the voltages aren't high enough to cause harm to humans any more.

Think of it like main and aux fuel tanks, except they're all the same size. While most electric car batteries are in the 400V range, if you run it as 8 separate 50V batteries, a single one isn't particularly dangerous. Run the wires all up to a disconnect in front of the firewall before you combine the voltages (series) and once you pull that disconnect, there's no more dangerous voltage.
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Yep. Already knew that. Did a photo shoot with some VFD guys who were cutting up old cars and they did a little briefing on it. For cars.

Wonder if that tiny thing has an external disconnect somewhere. Would make for a funny prank to do to your buddy flying it. Walk up to the outside of the airplane after he’s strapped in and doing his prep, wave hello and turn off his outside disconnect and walk away. Hahaha.

Only for the best of friends on that one, of course. Hahaha.

“You a**hole!” sounds better than “clear prop!” doesn’t it? LOL.

Of course you’d want to read their POH first and know the disconnect didn’t do anything that would damage anything.

All in good fun. :)
 
flyingcheesehead said:
I've always thought that it's silly that we all charge electric cars at home. Ideally, electric cars should be charged wherever they sit for long periods during the day, so that they can use energy from local solar rather than taxing the distribution grid. In fact, if there were solar-only charging stations wired to provide the right DC voltage, maybe we could get away without pushing the juice through an inverter and then rectifying it back to DC and the inefficiencies inherent in those processes.
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It's my understanding that the grid is under greatest load in the middle of a workday when air conditioners are running at peak. Since generators have to run 24/7 and there's little load on them at night, the power company charges less and why it's better/cheaper to charge overnight.

Maybe this is only in Los Angeles. If we built out more solar charging infrastructure this might change.
 
Cogito said:
It's my understanding that the grid is under greatest load in the middle of a workday when air conditioners are running at peak. Since generators have to run 24/7 and there's little load on them at night, the power company charges less and why it's better/cheaper to charge overnight.

Maybe this is only in Los Angeles. If we built out more solar charging infrastructure this might change.
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Depends where you are - A/C doesn't run here for most of the year. ;)

But, read up on the Duck Curve. More solar generation will take care of the air conditioners and the cars, but in the evening is where the real trouble will lurk if we don't get people to charge either on solar during the day or set their cars to kick on in the middle of the night.

But really, charging during the day is better for the overall grid since solar can be *very* local to the point of need, while the plants are usually miles away.
 
Salty said:
Here we go again. Electric planes make no sense. Totally impractical.
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Neither do solar charging stations at offices. Heh.

But man if you owned a company in a severely greenie location and business type that attracted such folks, you could make a little money on installing panels all over the freakin building and over the charging spots and take the money right straight out of the staff’s paychecks who used the thing to pay for building it, amortized at whatever number of years gave the best tax incentive, and whatever high made up maintenance number you wanted to use until you had a number of years of history and knew what that number would really be.

Put a dollar amount per KWh they use on it and take it right straight off the paycheck before direct deposit. It’s exactly the same model as government uses to hide the costs of taxes.

I bet getting employees to pay for your capital toy like that would work great in Boulder. They get to pay you a small profit instead of the gas station down the block for the “convenience” of having a charger at work, and you get to hold a press release about how wonderful your company is for the rest of the hive-minded community. Might even get local government to subsidize it right out of their paychecks or housing property taxes too!

Of course you’d also grid tie it “for cloudy days” and offer charging to non-employees after hours at a profit, too.

We already know the zealous will happily spend $40K on debt to change vehicles. The question is whether they’ll pay more than they’d pay for gas if you obfuscated it as a direct payment out of their paycheck. “We’re an awesome green company!” LOL.
 
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