world's first airline with electric-only aircraft

tahanson43206 · 2019-04-06 09:09:20

For kbd512 ...

In a number of your recent posts, you have spoken favorably of ammonia as a fuel storage medium for applications which can use electric power derived from fuel cells. I chose this one for a reply because it is explicit.

kbd512 wrote:

Let's go through another exercise where we compute the energy required using Hydrogen fuel cells. Maybe enough repetition will cause the basic concepts to sink in. If not, it's still an easy thing to do.
...
Our LNH3 is 1.5 times as energy efficient in this particular application. Notice how the efficiency of the gas turbine engine improves as the size of the engine increases? It's almost like there's a pattern developing here. Anyone here want to bet that our LNH3 energy equivalent is even closer to 1 for an even more fuel efficient aircraft like the GE90-powered 787?

It seems to me you may be showing the NewMars audience the potential for a technology wave with significant potential.

The key (it seems to me) is the human market opportunity ... The younger generations ** may ** be receptive to supporting a change to ammonia as an energy storage medium, and thus (potentially) ready to support initiatives to supply products and services on a global scale.

There are examples from recent history of individuals spotting potential wave technologies, and successfully building companies to develop, market, supply and support them.

Microsoft is the first example that comes to mind, when Bill Gates and his friends saw the potential for a BASIC interpreter that would run on the 8008 chip, and then on the 8080.

Amazon is an example of insight that the Internet could provide a pathway for delivery of products and services. Jeff Bezos started with books shipped from home (as I recall the story).

There are numerous other examples, and I hope other forum members will contribute their suggestions to this or another topic.

However, the point of my post here is to try to inspire the individual who will anticipate global demand for ammonia powered lawn mowers, small boats, and a zillion other product types.

You have already pointed out, following RobertDyck's original lead for this topic, that work is well underway to provide aircraft capable of operation using fuel cells supplied by ammonia to hydrogen delivery subsystems.

I am surprised that (so far) no announcements of automobiles powered by this technology have appeared, or at least, come to my attention.

Since Toyota (in particular) is betting heavily on fuel cell electric vehicles, I would expect them to try a small experiment with ammonia soon. There may already be a small team working on that concept at Toyota.

(th)

SpaceNut · 2019-04-06 13:27:59

The amonnia is another flavor of the hydrogen economy that seems a be a bit safer than straight forward hydrogen storage as it makes it less explosive before use thou it is toxic. It would be an on demand use system.

kbd512 · 2019-04-07 18:54:33

tahanson43206,

Science vs Desire
This is not about what I would rather use. It's about servicing basic design requirements to continue to use existing transportation technology with less energy (greater energy conversion efficiency to mechanical work) and less pollution (less CO2, to combat global warming). There are few practical applications for airliners that fly for 15 minutes to 1 hour before they must land. If you can't get the result you're after with a specific energy technology, then you move on to other technologies or resign yourself to using technology that you already have. As of right now, we simply can't get the energy output that so many people want by using existing battery technologies.

I have nothing against using batteries, alternative fuels, or any of the fuels we already use. I'm 100% against ignoring basic math and science, even if it tells us things that we don't want to hear. Some here want to ignore the energy economics of powered flight because they're after a specific result that isn't realistically achievable using any known or projected battery technology.

Gas Turbine Power-to-Weight and Fuel Economy
A jet airliner is a miniature power plant. It uses multiple megawatts of power to fly through the air at high speed, even in thin air at high altitude. The pair of CFM-56 turbofans under the wings a 737 are generating around 10,960lbf (lbs of thrust) at FL350 (35,000ft) at 523mph (max cruise speed). That may not seem like much compared to what it used to take off, but that figure still represents 15,284hp.

1hp = 550ft-lb/s (foot-pounds per second)

10,960lbf (pounds of thrust) * 767fps (523mph converted to feet per second) = 8,406,320ft-lbs/s

8,406,320 / 550 = 15,284hp <- See notes below

15,284hp = 11,397,277 watts

If the thrust-specific fuel consumption (SFC or TSFC) of the CFM-56 is 0.545lbs/lbf/hr (pounds of fuel burned per pound of thrust per hour), then...

10,960 * 0.545 = 5,973lbs / 2,709kg

Notes:
1. The mechanical work output changes with thrust and velocity.
2. It's very awkward to try to represent a constantly changing power output value, so jet engines are rated in pounds or kilo-newtons of thrust, typically static thrust (meaning the engine is not moving at all) at sea level.
3. Achievable thrust varies dramatically with air density. You can't achieve anything close to sea level static thrust at FL350 / 35,000 feet, for example. The CFM-56-7B27 generates 27,300lbf at sea level under standard atmospheric conditions, but that drops to a maximum of 5,480lbf at FL350 (5,480lbf * 2 = 10,960lbf), also under standard atmospheric conditions.

Gas Turbine Aircraft Rant
To travel at maximum constant speed at FL350 (without over-speeding the CFM-56 power core or the fan blade tips going supersonic, both of which are bad for the health of the engine), the 737's turbofan engines generate sufficient power to overcome 10,960 pounds of drag force (generated by the entire aircraft moving through the air at 523mph at 35,000ft) with thrust from miniature wings or airfoils or fan blades that we colloquially call "the fan" part of the turbofan engine. The power core also adds to the thrust generated as the hot exhaust expands out the back (this is the "jet" of hot air generated by the jet engine from combustion), but most of the thrust comes from the fan (because this is the most efficient way to generate thrust at high subsonic speeds). Thrust is probably 70% to 85% fan and 30% to 15% power core. The smaller you can make the power core and the bigger you can make the fan, the more fuel efficient the engine will become, right up until the tips of the fan blades enter the transonic region in terms of linear velocity, whereupon the tips start to go supersonic and generate massive wave drag and lots of noise and vibration from locally breaking Mach 1 in terms of linear velocity.

Propellers are actually the most efficient way to generate thrust, but the tips go supersonic long before the fan blades do because there's nothing to stop the acceleration of the air around their tips, unlike a fan that is contained in a shroud or duct. That very long-winded explanation was a way of saying that the scientists and engineers who design and build these things don't just pull ideas out of their rear ends. It's not random. It's not because they're bored. It's because the physics associated with aerodynamics dictates how and why something works the way it does.

Rant off...

Replacing Gas Turbines with Batteries
Please note that airliners don't intentionally fly at max cruise speed by choice, except to make up for lost time on the ground due to ground delays, in order to maintain the flight schedule. However, if they have to, then they do. Time is money in business. Wasting your customer's time is a surefire way to lose business. As Sheriff Buford T. Justice would say, "You can think about it, but doooooon't do it."

What would our prospective new battery technology need to store per kilogram of weight, in light of the 737's better fuel economy, as compared to the A320 (note that our A320 example from "Real Engineering" was flying with a reduced throttle setting, yet burning nearly as much fuel as the 737 at maximum cruise), to match fuel burn of the new 737-800 flying at max cruise when powered by its pair of CFM-56-7B27's?

11,397,277Wh / 2,709kg = 4,207Wh/kg

Someone may come out with a battery that stores that much energy tomorrow, but would you design and build an aircraft that relied on that to happen if you were an executive at Airbus or Boeing? I sure wouldn't, nor would I ever advise someone to undertake such an extremely risky venture on the off chance that that could happen in the near future. I would instead point to past progress on battery technology and search for viable alternatives.

What do batteries store now?: 260Wh/kg - Tesla batteries (actual commercial production technology)

Near future?: 1,000Wh/kg - Innolith's claimed breakthrough Lithium-ion (no independently verified evidence that I can find, but that doesn't mean the claim is not valid)

Requirement?: 4,000Wh/kg - at least this much, since the aircraft never gets any lighter as it flies, meaning you can never throttle back and still maintain airspeed as the "fuel" (electrons) are consumed to produce thrust

As turbofan engine technology becomes more fuel efficient, that required energy density figure keeps going up to a point (where it hits the thermodynamic efficiency limits of simple cycle heat engines- the Carnot efficiency limit). This is more applicable to long haul flights across oceans or continents than short hops. The ADVENT technology demonstrator program being developed for military aircraft engines is intended to optimize airflow to get closer to this limit in lower bypass (smaller fans) turbofan engines.

Appropriate Use of Available Technology
There are appropriate uses for batteries and there are inappropriate uses for batteries. Given the specific energy (proper scientific term), or "energy density" (an informal but now common informal reference to specific energy), of existing rechargeable battery technologies, we simply do not have the specific energy / energy density required to replace chemical energy from liquid hydrocarbon fuels. There are limits to every technology. Gas turbine engines don't scale down very well, don't throttle up and down very well (making them inappropriate for use in heavy vehicles like our M1 Abrams tanks), and aren't as good as diesel engines when it comes to fuel economy.

I don't believe, nor am I intentionally advocating for, LNH3 powered cars. The reason is that Lithium-ion batteries produce a sufficient power-to-weight ratio for practical application in terrestrial motor vehicles, handheld tools, and portable electronics. However, that ratio remains grossly insufficient to replace Jet A burned in a large turbofan engine. If the energy density is truly 1,000Wh/kg for the entire battery pack, then batteries appear sufficient to replace Jet A burned in a small turboprop (commuter aircraft) or turboshaft (helicopters) engine at low altitude. The empty weight of the vehicle is greater, but payload capacity remains unchanged.

Our M1 Abrams main battle tanks should be powered by LNH3. That's another example of an appropriate use of LNH3. In that application, the weight differential between the JP8 and LNH3 is 581lbs. The AGT-1500 gas turbine engine is also far heavier than equivalent fuel cell and electric motor weight. The M1's current AGT-1500 power pack weighs 2,500lbs and puts out a maximum of 1,118kW. The Intelligent Energy fuel cells would weigh 886lbs to produce 1,200kW. I don't know precisely what the electric motors would weigh because I don't know how much the speed reduction gearbox would weigh to reduce the motor's RPM to increase torque, but I have 1,614lbs to play with. Even if I had to use the existing gearbox, it still wouldn't weigh as much as the AGT-1500 power pack. I also know that the space claim from the fuel cells, even if we just drop in 12 of them in their existing automotive configuration from Intelligent Energy with no volume optimization at all, in order to produce the same 1,118kW of the AGT-1500, is far less than the AGT-1500. The onboard fuel cells are already much stronger than what is required to contain LNH3 at atmospheric temperatures and those are held in place with at least 1/4 to 1/2 inches of steel.

Yes, the LNH3 is toxic, but nowhere near as flammable as JP8. Fires and explosions are what kill tank crews, not the toxicity of the fuel or fumes from burning it. If we have what is essentially a non-flammable fuel that immediately disperses into the atmosphere upon fuel cell rupture, then none of our tank crews will burn alive from LNH3 in fuel cells, vs JP8 fuel cells, surrounding their fighting positions inside the tank. Perhaps gloves and goggles are required protection for fuel handling, but those are already standard issue equipment for all armored vehicle crew members.

Liquid Anhydrous Ammonia / LNH3 and Fuel Cells
First of all, liquid chemical fuels like kerosene, which is what Jet A is, is "good stuff" if you need extreme energy density. However, as we'll show here, liquid Anhydrous Ammonia, or LNH3, is "better stuff" because it stores well at moderate pressures at common sea level temperatures and weighs less than Jet A for equivalent energy content when catalyzed in a fuel cell. In the frigid temperatures found in the flight levels, LNH3 remains liquid at the pressures associated with ordinary fuel tank pressurization systems that are already required for jet aircraft to function.

Jet A
Specific Energy / Energy Density: 11.95kWh/kg
Weight per Gallon: 3.1kg
H2 Content per Gallon: 0.8892lbs to 1.026lbs (lower grades contain less H2 and it's variable)
kWh / gallon: 37kWh (11.95 * 3.1)
In the largest jet engines, like the GE90, you get 36% of that 37kWh out as mechanical work, so 13.32kWh

Liquid Anhydrous Ammonia / LNH3
Specific Energy / Energy Density: 6.99kWh/kg
Weight per Gallon: 5.69lbs / 2.58kg at -28F (1 gallon contains 0.458kg of H2)
H2 Content per Gallon: 1.01lbs
kWh/gallon: 18.04kWh

When the H2 from the LNH3 is cracked with a plasma cracker and fed through a 70% efficient PEM fuel cell, you get about 12.63kWh/kg.

Some here will note that that's slightly less than Jet A.

They're correct... Except that 1 gallon of Jet A is 1.15lbs heavier than 1 gallon of LNH3.

Why do we have to generate so much power to fight against so much drag force to keep our jet moving at a given speed?

We need a wing that's big enough to generate sufficient lift to keep our jet in the air. The wing has to be as big as it is because of WEIGHT!

In multi-thousand gallon quantities, what are we carrying significantly less of by using LNH3 instead of Jet A?

Weight, maybe. Hint, hint.

To generate 16MW of power at sea level, we need a 5,333kg fuel cell. The electric motors would weigh 1,067kg. Our total fuel cell power plant package weighs 6,400kg. The power provisioning differential is 1,668kg.

Our pair of CFM-56 engines weigh a minimum of 4,732kg. In reality they weigh significantly more than that once all the extra crap required is added. The 737-800 carries 6,875 gallons of Jet A, or 47,025lbs / 21,330kg. If the fuel was LNH3, then 6,875 gallons would weigh 39,118lbs / 17,744kg. Our fuel weighs 3,586kg less. Subtracting out the difference between the two power provisioning schemes, our bird is still 1,918kg lighter. Even if the fuel tanks require reinforcement to hold pressure, we wind up with a new 737 variant that doesn't pollute at all and comes in at the exact same weight as the kerosene burner it replaced.

But wait! There's more!

We're using 7,906 pounds less fuel per flight at equivalent takeoff weight. Our LNH3 costs about 1/4 of what Jet A costs at retail prices because it's so cheap and easy to make and we need 4 tons less per flight. Even if we're making it from LNG, we still come out on top in every way imaginable. It's better for the environment and the airlines bottom line in a way that no bean counter has to think twice about. Our electric motors have maintenance schedules that would make any airline service green with envy... because there isn't any. If there is, it's limited to replacing bearings or maybe a few pump motors for the fuel cells. The fuel cell catalysts will eventually need to be replaced, but that's a matter of disassembly and removal of what amounts to sheets of paper and some rubber gaskets. All low-cost items or recyclable items. In aviation, you recycle or recondition everything you can. Replacement is always a last resort, unless maintenance instructions specify replacement. There's nothing else in our power plants that wear out in any meaningful timeframe. If a bird gets sucked through the fan, then it gets shredded by the fan. They're strong enough now to absorb most impacts thanks to composites. CNT composites would ensure that the fan survives any bird strike at takeoff and landing speeds. If the fan blades remain intact, the motor keeps running as if nothing much happened instead of absolutely trashing the core of a very expensive air compressor. A good scrub with hot water and Dawn will rectify the results instead of a brand new engine.

1 gallon of LNH3 contains about 1.5 times as much H2 as 1 gallon of LH2 (Liquid Hydrogen), as is the case for gasoline and Jet A. LH2 or LCH4 have to be stored at cryogenic temperatures or at insane pressures that we can't achieve with lightweight storage containers. Only LNH3 can be stored at ambient atmospheric temperatures and moderate pressures (114psi at room temperature). We can easily achieve that with lightweight containers. The fuel pumps in Jet aircraft generally operate above that pressure. Jet fuel tanks are normally pressurized to a few psi above atmospheric at altitude. No fuel tank pressure equals no worky, for either fuel. We're above normal Jet A fuel tank pressurization with LNH3, but not absurdly above that.

We will need some sort of system like OBOGS (OnBoard Oxygen Generation System) to supply concentrated O2 to the fuel cell, else our achievable power output and thus thrust will decrease with an increase in altitude, just like a regular jet engine. Now that I think about that, maybe that shouldn't be onboard. If the aircraft breaks Mach at high altitude from generating too much thrust, bad things will happen unless it's designed to go supersonic. Nevermind. Skip that idea. SpaceNut brought it up.

elderflower · 2019-04-09 13:03:29

For oxygen concentration you need a compressor, then maybe some separation device to reduce the nitrogen concentration (pressure swing absorber perhaps). Compressors require considerable power to operate. More than half the power generated by a gas turbine goes into driving it's compressor. We may hope to do better than this to feed your fuel cells by not compressing excess air, since we are not restricted by the temperature at the gas turbine inlet as a jet engine is. You will have to account for the power to drive the oxygen system in your energy balance. Or try to make it work with ambient partial pressure of O2.
Notice that the conventional gas turbine engine performance improves with falling air temperature at height as the turbine inlet can be held at a safe temperature with an increased proportion of the available oxygen being used in combustion instead of dilution of the combustion products. The improvement in efficiency is considerable and is the main driver for flying jet aircraft as high as they do.

Last edited by elderflower (2019-04-09 13:25:44)

kbd512 · 2019-04-21 19:26:59

Elderflower,

A fuel cell will still work at high altitude, but it'll produce proportionally less power with proportionally less atmospheric O2 content to react with the H2. The same is true of all existing combustion engines except rocket engines, to include jet engines. The goal here was to illustrate the feasibility of creating a CO2-free alternative propulsion system that provides a like-kind replacement for existing turbofan engines. I've done my best to show that that's already feasible using current automotive LNH3 plasma cracker technology (Toyota), current automotive PEM fuel cell technology (Intelligent Energy), and axial flux electric motors (Magnax).

For what should be obvious reasons, I do not want the fuel cell to be able to produce more power than an existing turbofan engine that it's intended to replace. If the fuel cell powered plane makes sea level power at high altitude, then it can overspeed the fan and/or exceed the Vne of a subsonic airliner's airframe in level flight. Any design that intentionally permits that to occur is a bad design.

If you intended to design the fuel cells to be capable of producing more power in the event that one fuel cell is lost, then that's a different design issue that requires careful consideration of the tradeoffs made to achieve that functionality. The possibility exists, however remote, that enough power could be fed to one or more of the electric motors to overspeed the electric fans and/or airframe itself.

SpaceNut · 2020-12-10 20:47:43

Scientists built an ‘ion drive’ propulsion system that actually works

BB1bPoVq.img?h=511&w=799&m=6&q=60&o=f&l=f

So what exactly is an ion drive and how did MIT scientists manage to make a plane fly without fuel or propellers? It’s actually a fairly simple concept, though figuring out how to execute it took some time.
When air is ionized it is given an electrical charge. Because charged air particles are drawn to whatever the opposite charge is, be it positive or negative, it’s possible for a system to actually move air over a wing with nothing more than an electrical charge and cleverly-placed wires carrying either a positive or negative charge measuring 20,000 volts.
The electric field that is created causes the air to move swiftly over the wings in the same manner that it would if the plane were being pushed along by jet engines or pulled by propellers. The result is a silent electrical propulsion system that should, in theory, be incredibly reliable.

Seems they have come a long ways since we first heard of this design...

kbd512 · 2020-12-11 12:42:37

SpaceNut,

That article is a rehash of something that took place a couple of years back. However, researchers are, in point of fact, making progress on practical air-breathing ion thrusters / engines. These engines are interesting because of their thrust efficiency, meaning Newtons of thrust produced per kilowatt of input power. IIRC, jet engines are ~2N/kW and this engine could feasibly generate 110N/kW, thus a fuel cell supplying the power might be able to get away with producing 55 times less input power for the same thrust output. That would be nothing short of a game changer, at least as significant as the development of the internal combustion engine. It could make delivery of cargo by solar or fuel cell powered airships cheaper than cargo ship or railway. The near total lack of moving parts would also reduce maintenance costs to periodic repair of the airship's envelope / gas bags fabrics and periodic replacement of lifting gases. No doubt quite a bit of development effort is still required, but that's the potential of the air-breathing ion-engine technology. The heavier-than-air aircraft would also have far fewer moving parts and require far less fuel. An airliner would essentially take the form of a glider- no giant turbofans hanging under the wings and very slender "Hershey bar" wings for good performance at moderate subsonic speeds.

Remember that French AGA-33 concept aircraft?

Even if you didn't use air ionization propulsion, but instead used boundary layer ionization to reduce parasitic drag and turbulence, it's feasible to use less thrust for that 250 pax intercontinental airliner at cruise speed. By qualifying BNNT and CNT fibers as structural materials, the empty weight of AGA-33 could realistically be reduced from 70t to 35t, thus reducing the quantity of fuel required for a transatlantic flight. At weights like that, an airliner could afford the extra weight associated with wing folding mechanisms to make ground and gate operations simpler and easier, although the wingspan reduction associated with that much weight reduction might make the length of the wings a non-issue.

Since roughly half of the drag on an airliner in cruise is viscous drag (skin friction), if we could reduce that drag by some substantial fraction, then we could feasibly use smaller engines that produce less thrust and therefore fuel burn. In his experimentation, granted at lab scale, the man giving the lecture in the video linked below showed a 35% energy reduction by pulsing current through skin actuators and skin sensors operating in a feedback loop to reduce boundary layer flow turbulence (pretty significant since that nearly directly correlates to a thrust reduction while maintaining a target cruising speed):

Ahmed Naguib | Plasma Actuators

Here's an example where plasma flow control was substituted in lieu of control surface actuators, which would further reduce weight and improve controllability at low air speeds.

Aerodynamic Control Using Windward-Surface Plasma Actuators on a Separation Ramp

All that said, at the point at which you cut the structural weight by half, that's more than one quarter of the total maximum weight of the vehicle, which means you need to provide one quarter less aerodynamic lift, which means the drag from producing lift is reduced by a quarter, which reduces your thrust requirement by at least that much. If you start using centerline thrust with redundant electric motors and fuel cells, then you have no more asymmetric yaw from an "engine out" condition, so even less drag and weight associated with mounting the engines on the wings. Your landing gear can be reduced in size / weight at that point, too. This problem entirely revolves around pushing weight through the air at a given speed. In simple terms, weight reduction while providing the same strength and durability is a virtuous circle of design and operating benefits. The elimination or reduction of tail surface area or incorporation into a ducted fan housing would likewise reduce drag. I believe that's why Ampaire's TailWind eliminated the tail surfaces in favor of a vectoring thrust propulsion unit with vanes built into the tail propulsory unit for pitch and yaw control. An additional optimization for airliners to reduce wingspan, improve directional control, and reduce drag, all at the same time, would be box wings. A box wing is a kind of biplane design where the wing wraps around the top and bottom of the fuselage that's connected at the tips to prevent air from spilling over the wingtips and inducing drag, similar to the way modern airliners use winglets or raked wing tips, but even more effective. This design optimization would also permit very dense packing of the machines at the gates without wing folding mechanisms. However, a high fuselage mounted cantilever folding wing would still permit the densest packing possible while eliminating the possibility of an errant ground vehicle striking the wing.

The combination of all these systems optimizations, especially very thin folding wings with a nominal fuel load, would permit what I call a "conga line" or "train station" approach to airport design, such that airliners arrive, fold their wings and shut down their engine, are latched / locked by an electric ferry tug (larger variant of the remote control design that Mike Patey's company came up with) operated by a remote operator and software that sets minimum safe distances and taxi speeds, the passengers enter a terminal where they de-plane via 4 exits on both sides of the fuselage, the plane enters a fuel bunker area built into the building with an AFFF deluge system for firefighting during re-fueling, from there onto a "car wash" and composite inspection area to diagnose any micro-cracking, the fully fueled airliner is automatically weighed for W&B figures, it rolls forward again for simultaneous passenger and cargo / baggage loading with another set of W&B scales, and the next load of passengers boards from all 4 doors on both terminals (the 250pax load is divided into 4 groups for faster boarding / disembarking).

The purpose of all that is to drastically speed up airport operations, to produce consistent operational results to adhere to published time schedules (same as Shinkansen operations in Japan), reduce fuel burns associated with extended duration taxiing (the fuel cells will be kept warm to reduce material fatigue, not shut down completely), take ground taxiing operations out of the hands of pilots who can't see the "big picture" and may be distracted by staying on top of operating / troubleshooting their aircraft, and to rapidly identify unsafe for flight conditions such as airframe or propulsion system damage (because these conditions endanger everyone, not just the people aboard the plane). After you land and vacate the active runway, a semi-automated integrated tug system takes over control of ground operations to reduce the probability of accidents, eliminate the need for communicating where you're going (unless you have a maintenance issue, the tower automatically decides where you're headed- and everyone is headed to the same place, so no "special" terminals for corporations or "special people", just smooth traffic flow into / out of the boarding / disembarking areas), and the race track design eliminates the need for byzantine taxiway sprawl. The lack of service vehicles, apart from aircraft tugs, prevents aircraft from colliding with ground vehicles. Larger airports can have multiple lanes, same as larger train stations. We've already figured this problem out, so there's no need to reinvent the wheel. It works for trains and it'll work for aircraft with folding wings.

The reduction in wake turbulence associated with active boundary layer control will also reduce minimum following distances for successive airliners flying in the pattern during takeoff or landing, but the overall goal here is to eliminate as many potential errors and communications issues as we feasibly can, all while we achieve pretty spectacular efficiency improvements for our flight operations. The general public will surely appreciate the noise abatement from running fuel cells and electric fan propulsion units as well. For landings that don't require a go-around, it should be so quiet as to escape notice unless you're within the confines of the airport itself. People working near the airliners won't require hearing protection unless the propulsion unit is at full power, so baggage handlers and maintenance crews not running up the propulsion unit to full power will still be able to talk or yell at each other and hear normal verbal communications.

In closing, we now know enough about commercial aviation now that a total re-think of how we power airliners, conduct commercial air travel operations, and eliminate risks is in order.

Mars_B4_Moon · 2022-04-04 09:44:46

NASA Readies New Electric X-Plane For First Flight
https://hackaday.com/2020/04/28/nasa-re … st-flight/

Aircraft of the future: Sustainability the goal in new airline planes coming soon
https://www.traveller.com.au/aircraft-o … oon-h22vrl

update on the Ukraine aircraft mentioned in this thread

Antonov An-225 wreckage: Footage shows world's largest plane destroyed in Ukraine
https://www.fox13news.com/news/antonov- … in-ukraine

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#51 2019-04-06 09:09:20

Re: world's first airline with electric-only aircraft

#52 2019-04-06 13:27:59

Re: world's first airline with electric-only aircraft

#53 2019-04-07 18:54:33

Re: world's first airline with electric-only aircraft

#54 2019-04-09 13:03:29

Re: world's first airline with electric-only aircraft

#55 2019-04-21 19:26:59

Re: world's first airline with electric-only aircraft

#56 2020-12-10 20:47:43

Re: world's first airline with electric-only aircraft

#57 2020-12-11 12:42:37

Re: world's first airline with electric-only aircraft

#58 2022-04-04 09:44:46

Re: world's first airline with electric-only aircraft

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