sounds kinda weird. IC engine planes get more efficient with lower fuel (lower weight)whereas with Electric ones, you still have to carry the weight around with lower power.
First all-electric seaplane takes flight in B.C.
91–100 of 188 posts
Re: First all-electric seaplane takes flight in B.C.
#92Earlier quoted context omitted.
Also batteries weigh the same at landing and takeoff while jets rely on the reduced weight from fuel burn for safe landing.
No, not for safe landing. If a jet couldn't land safely while fully tanked then they would not be able to land in emergencies happening early in the flight. They rely on the plane being lighter from fuel burn and therefore more efficient to extend their possible flight time, but not for safety.
I guess it depends on what you call a safe landing. For large airplanes the maximum takeoff weight is typically greater than the maximum landing weight. If an airplane lands overweight it can no longer fly until it has been inspected and repaired. Most emergencies will involve flying around for long enough to get the aircraft within the acceptable weight limit. Some older aircraft have the ability to dump fuel, although I don't know of any new ones that have this capability.
Needing to land before getting under weight usually means a crash landing. In modern times, very few things like fire or an engine self-destructing will require immediately getting out of the air. It is usually better to fly in a straight line, figure out what is going on, figure out where to land, then land. This lets you get underweight, lets you communicate with air traffic control, lets emergency services prepare, etc.
Re: First all-electric seaplane takes flight in B.C.
#93Earlier quoted context omitted.
>"Anyone know how far we are from electric jets? Is such a thing even possible?" Electric will never replace long haul jets barring a revolutionary breakthrough in battery technology. But that's not the point. Much of commercial aviation takes place on distances of around 100 to 500 miles. That is, too far to drive but not quite far enough to take advantage of the efficiency of jet engines at high speed, high altitud…
Would a hybrid model be more effective? Using diesel generators to power electric motors?
Hybrids are interesting because you can reach higher bypass ratio's because you can power n number of ducted fans off m engines.
Currently increasing fan sizes are getting problematic. That is the problem with the 737 MAX. The fan diameter of the new engines is too large to fit between the bottom of the wing and the ground. So it had to be mounted forward and up which fucked up the aerodynamics.
Two other advantages are, potentially maintaining thrust in an engine out situation. When you lose an engine not only do you lose half your power but the thrust is unbalanced. And faster throttle response. Turbine lag is a big issue with jetliners.
Note: The reasoning behind high bypass turbofans is thrust is proportional to delta v times the mass flow rate. Where power input is proportional to delta v squared. Bigger the fan the more efficient you are and the less fuel you use.
Diesel is kinda interesting. Manufactures are developing diesel engines for light aviation. I suppose you could have a hybrid diesel/electric aircraft.
Re: First all-electric seaplane takes flight in B.C.
#94Earlier quoted context omitted.
Also batteries weigh the same at landing and takeoff while jets rely on the reduced weight from fuel burn for safe landing.
No, not for safe landing. If a jet couldn't land safely while fully tanked then they would not be able to land in emergencies happening early in the flight. They rely on the plane being lighter from fuel burn and therefore more efficient to extend their possible flight time, but not for safety.
An emergency overweight/crash landing is the opposite of a safe landing.
Airliners will dump fuel or keep flying to get below maximum landing weight if possible. If they're still overweight and manage to land without issue, the plane will need to be inspected and repaired before it can fly again.
Re: First all-electric seaplane takes flight in B.C.
#95You can do small aircraft like this, no problem. The trouble is you can't scale it up, due to how quickly the power and energy demands go up. This thing is 560 kW and gets a range of 86 nmi; an A320 is around 40 000 kW and has a range of 3 500 nmi, while an A380 is around 80 000 kW and has a range of 8 500 nmi. Going from this DHC-2 to the A380 requires an increase in energy storage by a factor of around 14 000x, whi…
This is not true. It's easier to scale up. You get more efficient. Scaling up an electric motor is not particularly hard. Some of the largest machines in existence are electric. Power is not a challenge for electric. In fact, this electrified seaplane has much more power (560kW) than the original radial piston engine one (336kW), and even more than the turboprop conversion (510kW). A LOT of very confident people on t…
I'm not saying it's impossible to make a 5, 10, 15 seater all-electric work. I'm saying a 100 passenger all-electric will never fly without a revolution in battery tech.
You say "just increase mass of the vehicle which is battery". If you read about this airplane you find that since they are using batteries with an appropriate safety rating for aviation, they've used all the space and mass already:
"this eBeaver isn’t carrying passengers — there isn’t room — and will only have a 15-minute endurance with a 25-minute reserve."
https://www.skiesmag.com/news/harbour-air-makes-history-with...
I tried finding concrete info about the Eviation Alice, but the best I could find was a photo of an unpowered full-scale model. They've been saying the first flight test is a couple of months away for more than one year it seems.
Re: First all-electric seaplane takes flight in B.C.
#96You can do small aircraft like this, no problem. The trouble is you can't scale it up, due to how quickly the power and energy demands go up. This thing is 560 kW and gets a range of 86 nmi; an A320 is around 40 000 kW and has a range of 3 500 nmi, while an A380 is around 80 000 kW and has a range of 8 500 nmi. Going from this DHC-2 to the A380 requires an increase in energy storage by a factor of around 14 000x, whi…
We can accomplish the same by producing the jet fuel using electricity. Realistically this will likely involve methane (natural gas) extracted from the ground and water, but it could one day be carbon neutral using captured carbon. The trick is to use clean energy like nuclear of renewables. There was an article on HN just recently about doing that with portable nuclear generators like those used on ships, this could be done right in the airport.
We already have a fantastic dense energy battery called kerosene. All we need to do is make it carbon neutral and our existing aviation tech won't even need to change.
Re: First all-electric seaplane takes flight in B.C.
#97You can do small aircraft like this, no problem. The trouble is you can't scale it up, due to how quickly the power and energy demands go up. This thing is 560 kW and gets a range of 86 nmi; an A320 is around 40 000 kW and has a range of 3 500 nmi, while an A380 is around 80 000 kW and has a range of 8 500 nmi. Going from this DHC-2 to the A380 requires an increase in energy storage by a factor of around 14 000x, whi…
Also batteries weigh the same at landing and takeoff while jets rely on the reduced weight from fuel burn for safe landing.
Isn't fuel vapor more dangerous than liquid fuel though?
Contained vapor creates an explosion, while liquid must evaporate first.
Re: First all-electric seaplane takes flight in B.C.
#98Off topic and stupid, but could an electric plane be outfitted with lightning rods and/or lightning rockets to attract lightning strikes in order to charge the batteries?
I'm not sure about if its possible, but in the context of where this plane is flying, there is only lightning once or twice per year.
Re: First all-electric seaplane takes flight in B.C.
#99You can do small aircraft like this, no problem. The trouble is you can't scale it up, due to how quickly the power and energy demands go up. This thing is 560 kW and gets a range of 86 nmi; an A320 is around 40 000 kW and has a range of 3 500 nmi, while an A380 is around 80 000 kW and has a range of 8 500 nmi. Going from this DHC-2 to the A380 requires an increase in energy storage by a factor of around 14 000x, whi…
the scaling problem might be real, but it's not really a problem for harbour air, whose primary routes are ~50km from vancouver to victoria or ~80km from vancouver to whistler on nothing bigger than a twin otter.
Re: First all-electric seaplane takes flight in B.C.
#100You can do small aircraft like this, no problem. The trouble is you can't scale it up, due to how quickly the power and energy demands go up. This thing is 560 kW and gets a range of 86 nmi; an A320 is around 40 000 kW and has a range of 3 500 nmi, while an A380 is around 80 000 kW and has a range of 8 500 nmi. Going from this DHC-2 to the A380 requires an increase in energy storage by a factor of around 14 000x, whi…
This is not true. It's easier to scale up. You get more efficient. Scaling up an electric motor is not particularly hard. Some of the largest machines in existence are electric. Power is not a challenge for electric. In fact, this electrified seaplane has much more power (560kW) than the original radial piston engine one (336kW), and even more than the turboprop conversion (510kW). A LOT of very confident people on t…
Cars are not airplanes. Electric cars are much heavier but weight isn't a big problem on the road. That's why they work, and they're still catching up to traditional range expectations.
With airplanes, you have to lift that weight using the same energy stored within. In that case, energy density is the absolute issue. Nothing else matters.
There's no magical solution, a high-school physics class will teach you how to calculate the potential energy requirement to lift up a certain amount of weight, and dividing by energy density and volume of current battery tech does not lead to a working jet any time soon.