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Researchers Explore New Batteries To Power Electric Planes (technologyreview.com)
Can researchers built a new kind of battery powerful enough to fuel an electric airplane? MIT's Technology Review profiles a company co-founded by MIT materials science professor Yet-Ming Chiang:
He and his colleague, Venkat Viswanathan, are taking a different approach to reach their next goal, altering not the composition of the batteries but the alignment of the compounds within them. By applying magnetic forces to straighten the tortuous path that lithium ions navigate through the electrodes, the scientists believe, they could significantly boost the rate at which the device discharges electricity. That shot of power could open up a use that has long eluded batteries: meeting the huge demands of a passenger aircraft at liftoff. If it works as hoped, it would enable regional commuter flights that don't burn fuel or produce direct climate emissions...
The initial plan is to develop a battery that could power a 12-person plane with 400 miles (644 kilometers) of range -- enough to make trips from, say, San Francisco to Los Angeles, or New York to Washington. In a second phase, they hope to enable an electric plane capable of carrying 50 people the same distance.... Last year, the company announced plans to deliver a line of "hybrid to electric" aircraft with room for 12 passengers in 2022. At launch, the company intends to offer a hybrid plane with a gas turbine and two battery packs capable of flying around 700 miles (1,127 kilometers), as well as an all-electric version with three battery packs and a range of less than 200 miles....But crucially, the plane itself is expected to feature an open architecture that allows owners to switch out these modules over time, enabling them to upgrade to better batteries developed in the future or shift from hybrid to all-electric operation.
About 2% of the world's CO2 emissions come from air travel, and it's one of the fastest-growing sources of greenhouse-gas pollution. "More than a dozen companies, including Uber, Airbus, and Boeing, are already exploring the potential to electrify small aircraft," the article points out, "creating the equivalent of flying taxis that can cover around 100 miles (161 kilometers) on a charge. The hope is that these one- or two-passenger vehicles -- in most cases envisioned as autonomous vertical takeoff and landing aircraft -- could shorten commutes, ease congestion, and reduce vehicle emissions."
But with less ambitious batteries, "these would largely replace car rides for the rich, not displace air travel."
The initial plan is to develop a battery that could power a 12-person plane with 400 miles (644 kilometers) of range -- enough to make trips from, say, San Francisco to Los Angeles, or New York to Washington. In a second phase, they hope to enable an electric plane capable of carrying 50 people the same distance.... Last year, the company announced plans to deliver a line of "hybrid to electric" aircraft with room for 12 passengers in 2022. At launch, the company intends to offer a hybrid plane with a gas turbine and two battery packs capable of flying around 700 miles (1,127 kilometers), as well as an all-electric version with three battery packs and a range of less than 200 miles....But crucially, the plane itself is expected to feature an open architecture that allows owners to switch out these modules over time, enabling them to upgrade to better batteries developed in the future or shift from hybrid to all-electric operation.
About 2% of the world's CO2 emissions come from air travel, and it's one of the fastest-growing sources of greenhouse-gas pollution. "More than a dozen companies, including Uber, Airbus, and Boeing, are already exploring the potential to electrify small aircraft," the article points out, "creating the equivalent of flying taxis that can cover around 100 miles (161 kilometers) on a charge. The hope is that these one- or two-passenger vehicles -- in most cases envisioned as autonomous vertical takeoff and landing aircraft -- could shorten commutes, ease congestion, and reduce vehicle emissions."
But with less ambitious batteries, "these would largely replace car rides for the rich, not displace air travel."
This could be slightly more significant than one might think. While these small planes aren't the main type most people think of when they think of "airplanes", they happen to be roughly the least efficient transportation available. Less efficient per passenger than large airliners.
To give one well-known example, when Al Gore and his wife go to dinner, his G-11 B burns 578 gallons per hour. ( 0.8 mpg).
Replacing transportation that gets 0.8 MPG with potentially renewable energy is an easy win.
Mpg = mph / gph
San Fran to LAX is a heavily traveled route using aircraft like the A320.
I don't know if 12 and 50 passenger flights can compete on price.
They compete on convenience by NOT flying from SFO to LAX, and instead flying from/to smaller regional airports.
I would pay a premium to fly directly from Reid-Hillview in San Jose, which is a 15 minute walk from my house, directly into Santa Barbara or Orange County Airports. That would save me $60 on Uber cost for every trip, and I would be happy to pay that much more for the airfare just to save the time.
A 12-50 person aircraft is often used by people with more money than sense, such as CEOs or hollywood types. Cost per passenger mile may be less important than the appearance of being environment conscience. They can also write these costs off as a business expense.
They are also how people get from small local airports to larger hubs and form the working group of the various small commuter airlines that go from hubs to regional or local airports.
For the "power at take off" issue, why not steal the idea of an assisted take off from the Navy and the steam catapult? Since there is a much longer runway to work with the assistive acceleration wouldn't need to be as violent and sudden, which could make it usable for passenger if not cargo. No need to borrow the other half of the Navy solution and install arrestor hooks, still have a nice long runway to land on.
Don't blame me, I voted for Kodos
Indeed airplane design is largely about keeping weight as low as possible. The lighter the plane is, the farther, faster, and better it will fly per [any useful measurement]. Pretty much anything you try to improve on a plane can be improved by reducing the weight and then re-optimizing* the other parameters, especially fuel efficiency.
Tomorrow I'll finish building yet another electric-powered model I'm building. It flies for a long time for a battery-powered model, 20 minutes of more. To achieve that, I ended up with a max speed of only about 22 MPH. To make the batteries last twice as long, I'd need about four times as much battery, because roughly half the battery power is used to lift the batteries.
* Someone who knows gliders may be thinking about the fact that a glider will go faster if you add weight. That's true it'll glide for a shorter time, faster - if nothing else changes. If you don't optimize for the lighter weight, it'll go down faster and go forward faster. If you DO design for the lighter weight, the lighter glider will plain fly better all around.
why not steal the idea of an assisted take off from the Navy and the steam catapult?
It's one of those catch-22 situations; no manufacturer is going to build a plane which requires that system until the system is in use on a very large number of airfields .... and no airfield is going to pay to install those systems until there are planes which actually need them.
Reading the web site, I think the /. summary is misleading.
They wouldn't go from SFO to LAX. They would go SQL to SMO. From their site:
Today
Route SFO to LAX
Door-to-door time H:MM 4:40
Fare $130
Zunum
Route: SQL to SMO
Door-to-door time H:MM: 2:16
Fare $121
They must be projecting significantly cheaper operational costs to make regional airport service profitable.
I like the smaller regional airports but they may not have the connectivity you need to get where you want to go.
Another thing they mention: possibly flying without a pilot on board. That will be interesting.