Sun Flyer - All electric airplane

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.



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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Problem is solar still isn’t affordable. The only solar car charging station I’ve seen cost over 40 grand. I’ve seen house solar systems going for just under that but I’m still not in a position to upgrade yet. Hard to pay that much for solar when I can charge my Volt on the grid for $1.30 per charge.
 
I think these are great for the training market and might be great for GA in the near future. For trainers 2-3 hrs is more then enough bat time. Most of my training flights were around 1-1.5 hrs. Unload take your battery in and place it in the charger, the next student and CFI can be walking out to the plane with their bats already charged up... slip them in lock them in place and off you go. I don't see any reason why this can't work for training new pilots. I just hope it makes training less expensive.

In the near future I think for cross country electric plane they should try to get a 1 or 2 person aircraft that can haul maybe 50 lbs of gear. This plane needs to cruise at 140-150kts in my opinion to be a real x-country machine. It would need 4 hrs of bat time as a minimum in my opinion. That would accomplish many of the missions GA pilots fly. Personally 90% of my missions are solo and would fit in that window. Better yet would be that you could land and charge the plane to say 80% power in 30-40 minutes. Even if getting to a full charge took 4 hrs, if I could charge up to around 80% in 30-40 minutes this would be find. This is how my cell phone works today. I can get to 80% really really fast. The last 20% of charge is what takes the most time. So if you had a longer mission you could now extend to say a 6 hr flight with a 30 minute fuel/charge stop. Most of us want to get out of the plane after 3-4 hrs anyway. Plug in, grab a soda, use the RR then 30 minutes later you are back in the air with another 2 hrs of cruise time. I think this would be sufficient.

No I don't see this aircraft replacing the G36 or light twins anytime soon. But for a person who only needs 1 or 2 seats and does not need to go more than 400 nm on most missions this could be a game changer in the near future.
 
pp47021 said:
I think these are great for the training market and might be great for GA in the near future. For trainers 2-3 hrs is more then enough bat time. Most of my training flights were around 1-1.5 hrs. Unload take your battery in and place it in the charger, the next student and CFI can be walking out to the plane with their bats already charged up... slip them in lock them in place and off you go.
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I don't think anyone is going to be swapping batteries in these things. Even if it's only 100hp equivalent and the battery lasts two hours, that's a 150kWh battery, which will weigh 2200 pounds. Kinda hard to carry in your flight bag. ;)

Admittedly, I think the actual hp of these things must be lower. I need to learn more about the hp/torque relationship and what an electric plane really needs in terms of battery capacity.
 
flyingcheesehead said:
I don't think anyone is going to be swapping batteries in these things. Even if it's only 100hp equivalent and the battery lasts two hours, that's a 150kWh battery, which will weigh 2200 pounds. Kinda hard to carry in your flight bag. ;)

Admittedly, I think the actual hp of these things must be lower. I need to learn more about the hp/torque relationship and what an electric plane really needs in terms of battery capacity.
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Methinks you didn't watch the video.
 
flyingcheesehead said:
I don't think anyone is going to be swapping batteries in these things. Even if it's only 100hp equivalent and the battery lasts two hours, that's a 150kWh battery, which will weigh 2200 pounds. Kinda hard to carry in your flight bag. ;)

Admittedly, I think the actual hp of these things must be lower. I need to learn more about the hp/torque relationship and what an electric plane really needs in terms of battery capacity.
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Most of the electric planes in development have swappable batteries from what i have seen. They slide in and out fairly easy. Each of the major players have their own way of doing this but it seems like a fairly universal feature. The batteries are big and look to weigh a fair amount but nothing a person in decent physical condition can't handle. I bet someone would develop a cart to wheel the old batteries in and the fresh ones out. I am not saying these things are going to change the world of aviation tomorrow. But they are coming, they will get better each year, technology will keep advancing, and one day they will be a contender for GA pilots looking to buy a plane in my opinion.
 
pp47021 said:
Most of the electric planes in development have swappable batteries from what i have seen. They slide in and out fairly easy. Each of the major players have their own way of doing this but it seems like a fairly universal feature. The batteries are big and look to weigh a fair amount but nothing a person in decent physical condition can't handle. I bet someone would develop a cart to wheel the old batteries in and the fresh ones out. I am not saying these things are going to change the world of aviation tomorrow. But they are coming, they will get better each year, technology will keep advancing, and one day they will be a contender for GA pilots looking to buy a plane in my opinion.
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A battery pack costs orders of magnitude more than a tank of gas, and they have a limited service life (the more energy density, the lower the service life). Swapping them out isn’t a solution to the problem EVs have.

The energy density difference between batteries and gas is large when the tanks are full. At the end of the flight, it’s 10 times worse because batteries weigh the same when they are empty.
 
labbadabba said:
Yes, but did it land?
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I always note what they don't show in these videos. Climbing, turning, landing.... This one reminded me of that flying car prototype from a few years ago. I'm impressed that it even got off the ground, but it's got a long way to go before it's really flying.
 
I suspect they could be a nice tool for flight schools. Yes, you have additional capital outlay for multiple battery packs and chargers (swapping the packs is the only way I see to make the flight schedules for schools) at least for primary training. Once past initial maneuvers and local practice flights, the practicality wears off fast. 150nm cross country? I'm not sure that would work. And if you have to change planes at that point, what's the impact of primacy?

For general use? I suppose if all you do is tool around locally (or the occasional $100 hamburger) it'd be OK. But if you have to refuel? Now you're stuck until you can recharge (a few hours? Remember, unless these things are very wide spread, there won't be high current outlets for rapid chargers available. Assuming you carry a "slow" charger with you and some FBO will let you plug in, you can take a few hours and charge. It's OK if you fly 2 hours and overnight.

Anyway, my $.02. Easily worth 2 cents more than you paid for it...
John
 
I have seen a video on the Sun Flyer battery packs. They are swappable, so "refueling" is a matter of dragging a cart out to the plane, swapping out each pack - about the size of a small suitcase - then pulling the cart back for recharging. I don't remember the recharge time, but I would expect it to be hours.
 
bflynn said:
I have seen a video on the Sun Flyer battery packs. They are swappable, so "refueling" is a matter of dragging a cart out to the plane, swapping out each pack - about the size of a small suitcase - then pulling the cart back for recharging. I don't remember the recharge time, but I would expect it to be hours.
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Correct. I believe they mentioned six batteries, so a rolling cart would probably be easily moved back and forth to swap them out. The gentleman in the video didn't appear to be straining too much to install one. I'd think a rental outfit would probably need at least 2 spare battery sets for each aircraft in order to keep them charged enough for a 6-8hr flight day. Not cheap, but probably doable. It wouldn't be useful for cross-country work, but I'm sure battery tech will get closer to 2hrs useful in time. Again, this aircraft is just about pointless for anyone who wants to go more than 30 miles from the home drome without recharging, but it probably works well for flight schools doing the first 20hrs of training for private pilots where they aren't leaving the immediate area much.
 
bflynn said:
I don't remember the recharge time, but I would expect it to be hours.
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All Lithium batteries, from a single cell to an array of a million cells charge in the same amount of time - given a sufficiently large charger and power source.

Which is... about:
20mins 0% to 50%
40mins 0% to 80%
2 hours 0% to 100%
 
deonb said:
All Lithium batteries, from a single cell to an array of a million cells charge in the same amount of time - given a sufficiently large charger and power source.

Which is... about:
20mins 0% to 50%
40mins 0% to 80%
2 hours 0% to 100%
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It’s the “sufficiently large charger” that gets harder as the size goes up.
 
pp47021 said:
Most of the electric planes in development have swappable batteries from what i have seen. They slide in and out fairly easy. Each of the major players have their own way of doing this but it seems like a fairly universal feature. The batteries are big and look to weigh a fair amount but nothing a person in decent physical condition can't handle. I bet someone would develop a cart to wheel the old batteries in and the fresh ones out. I am not saying these things are going to change the world of aviation tomorrow. But they are coming, they will get better each year, technology will keep advancing, and one day they will be a contender for GA pilots looking to buy a plane in my opinion.
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The 85 kW battery in a Tesla S weighs 1,200 lbs. That's 120 lbs more than the empty weight of a Cessna 152.

Just because you see promo material showing the ease of battery swaps doesn't mean it's accurate.
 
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