I'd get one but I have a rule I follow "Never fly a plane that you outweigh"
Posted on 09/19/2021 4:14:52 PM PDT by American Number 181269513
Rolls-Royce Aerospace makes jet engines that power many of the world’s airplanes. While they are state of the art in terms of efficiency, they also leave a lot of greenhouse gas emissions in their wake.
The company has been a leader in developing electric propulsion systems for airplanes in order to help lead the world forward into a future of zero-emissions flight. Getting there will involve lots of innovations. The major hurdle is that batteries have a much lower energy density per unit of weight than jet fuel.
Let’s dig into that a bit. According to JetPack Aviation, a liter of jet fuel has an energy density of 9.6 kWh and weighs about 0.8 kilograms. That translates to 12 kWh per kilogram. In comparison, some of the best lithium-ion batteries have an energy density of 265 Wh per kilogram. The net result? Jet fuel has almost 50 times more energy available per kilogram to power an airplane than batteries do.
But the analysis doesn’t stop there. While jet fuel is energy dense, even the best combustion engines are not all that efficient at converting that energy into forward motion. JetPack says the inefficiency of internal combustion means that 1000 pounds (453.59 kg) of jet fuel yields only about 14 times more power than 1000 lb (453.59 kg) of batteries. A lot of that wasted energy goes out the back of the engine and into the atmosphere.
The net result is the “fuel load” for an electric airplane will be much greater than it would be for a conventional jet aircraft. In point of fact, cramming enough batteries into an airplane to make it fly leaves precious little carrying capacity for cargo and passengers, let alone a pilot.
Rolls-Royce Aerospace has been hard at work developing an electric airplane that can fly faster than 300 mph (that’s 483 km/h for those who insist on using the metric system), making it the fastest electric airplane ever built. This week, the finished plane made its first sustained flight. It was in the air for 15 minutes. I leave it to you to convert that to parsecs if you wish. And if you think 15 minutes isn’t very long, remember Wilbur and Orville Wright’s first powered flight at Kitty Hawk lasted a mere 12 seconds and that led to some pretty amazing things.
Rolls-Royce Aerospace says the test flight is “the beginning of an intensive flight testing phase in which we will be collecting valuable performance data on the aircraft’s electrical power and propulsion system,” according to Engadget. The company claims the single seat airplane has “the most power-dense battery pack every assembled for an aircraft,” but gives no specifics. It uses a 6,000 cell battery pack with a three-motor powertrain that currently delivers 400 kW (500+ horsepower).
The flight comes about a year after the originally scheduled takeoff and about six months after taxi trials. Rolls-Royce is developing an air taxi with aircraft manufacturer Tecnam with the goal of delivering an “all-electric passenger aircraft for the commuter market.” It has also worked with Siemens and Airbus on another e-plane concept.
The project is being funded by the Aerospace Technology Institute and the UK government as a preliminary step toward creating all-electric passenger planes. “This is not only about breaking a world record; the advanced battery and propulsion technology developed for this program has exciting applications for the Urban Air Mobility market and can help make ‘jet zero’ a reality,” says Rolls-Royce CEO Warren East.
Eviation has already created a production prototype of a 9 passenger electric commuter plane with a range of 440 nautical miles (815 km) and a cruising speed of 220 knots (407.44 km/h, 253 mph, or 317 feet per second, if you prefer). United Airlines has also invested in Swedish startup Heart Aerospace and ordered 100 of its electric short-haul passenger planes to be delivered by the end of this decade.
Electric flight is coming, maybe not tomorrow, but soon. Batteries with higher energy densities will be the key that unlocks their potential. Air travel accounts for about 7% of global emissions, so anything that reduces the amount of emissions from aircraft is welcome. Our children will surely fly in electric planes and find nothing remarkable about doing so.
The thrust of a modern turbofan is nearly all from the ducted fan not the gas generator at the core. The split is 75%+ from the fan alone. Same for the unducted fan the majority of the thrust comes from the blades not the gas turbine which has had most of its energy extracted in the turbines to drive the fan be it ducted as in conventional turbofans or unducted propfans. Turboprops work the same way the second fastest and longest range bomber in the world is the TU Bear Russian bomber it is as fast or faster than a 737 and is driven entirely by props at well over 500 mph. How the ducted fan, unducted fan, or prop is spun is irrelevant the thrust is from moving large amounts of air rearward.
The GE90 has a three metre wide fan at the front it takes a 100,000 hp gas generator core to spin it and generates 100000lbs of thrust the gas core is a small fraction of the thrust. That same gas core is used to drive Navy destroyers propellers with zero thrust from the gas core being used to drive that ship. It’s convenient to be able to dump the hot gas directly aft and get some residual thrust out of it in an aircraft but make no mistake modern turbofans are ducted fans first.
I’m willing to bet a month’s mailbox money that Audi has smarter engineers vs luddites in a mancave. Note that with the modular set up only a standard 480v three phase commercial power supply is needed.
https://www.engadget.com/audi-is-testing-high-speed-charging-hubs-lounges-100949218.html
UT Austin the coinventor of the original LI Ion cell is on the task.
https://news.utexas.edu/2017/02/28/goodenough-introduces-new-battery-technology/
Never thought about the energy requirements for a fill up. Since the gas pumps are low pressure then I assume that several gas pumps could operate on a 20 amp circuit.
I guess it already takes a good amount of electricity to charge an electric car overnight. It is interesting who you equate what it would take charge one in a couple of minutes... If that were even possible. Which it is not.
My parents bought the paperback novel for me when I was maybe nine. I still have it, although it’s in three separate pieces; has some nice color stills from the first movie in the center pages. I recall Palpatine being mentioned right at the start, the character who became the emperor; it appeared that he was being controlled by bureaucrats from the way it was written, although there was enough ambiguity to indicate that he was actually running the show.
What? A white guy and a white gal on the task!? It’ll never work.
Well I never claimed to be smarter than the average engineer, but the article you linked says 23 minutes charge time at 270 kW, which is 362 hp. A typical gas-powered car fills in about one-tenth that amount of time, and dumb as I am, 362x10 comes out to 3620 hp, which is within 10% of the number I gave, which was an approximation (note I said "about 4000 hp").
Power calculations typically come out the same whether your in a man-cave like me, or out ridin' tall in the saddle in Marlboro country.
The pump itself uses only a very small amount of power, probably under one horsepower. But with that small amount of power, the pump moves (liquified) energy at a much higher rate.
That's my point. That gasoline is a very space- and time-efficient way of storing and moving energy. You can move a heck of a lot of energy pretty fast with a little electric pump if you're pumping gasoline. Diesel is even better; its energy density is higher than that of gasoline.
Not that many light, 300 MPH airframes out there.
NXT
SX300
Lancair
to name a few...
I'd get one but I have a rule I follow "Never fly a plane that you outweigh"
Roughly 500 HP? We were up against Germany and Japan in the 1930s and didn’t have enough horse power in our airplane engines until we could generate about 2,200 HP to rival their designs for power. 500 HP is useless except for a private light plane. Sure, it’s fun to work with battery technologies, but this means absolutely nothing except to a hobbyist. I’ll stick with oil powered flight for now.
Problem is the weight of the batteries is so high you can only fly it by remote control
Batteries with higher energy densities will be the key that unlocks their potential.
Sounds suspiciously like the same claims made about every other supposed wonder tech
Basically “one day the miracles will happen and we will have x tech at low cost efficiency”
So “geniuses” what the environmental costs of producing, and disposing, of all those magic batteries?
Also electric powered vehicles do not get lighter as the energy is used as with a fueled vehicle.
“The thrust of a modern turbofan is nearly all from the ducted fan not the gas generator at the core.”
Looks like an open prop is more efficient than a ducted fan. Why, then, was a ducted fan ever used. The ducting itself produces drag. Perhaps the ducting justifies itself because it reduces turbulence at the outer edge of the blades.
I could also ask why those fancy wide blades weren’t used years ago.
You got that right. I want one on my hang glider :P WW forever
WW HP and Euro Sport
Torrey Pines, Mt. Laguna, Saboba, Horse Canyon, Little Black, Big Black, Blossom...
That is what I said.
You did, just all the technical data got to me and I stopped reading your post after the 1st paragraph. But great information.
You did, just all the technical data got to me and I stopped reading your post after the 1st paragraph. But great information.
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