Electric and Hydrogen aeroplanes - feasibility and issues

Just found this thread. Rather than speculate wildly, I think it more useful to see where these technologies are in today's markets and in what directions they might develop from here.

First, hydrogen.
Fuel cells are used in a few specialist vehicles, both ground and air. But mass-market quality remains elusive. Expect the rollout to keep moving slowly, as each small advance opens up another niche.
Liquid hydrogen is strictly space rocket material, and even then rare on first stages which it bloats in size. The major aerospace companies are increasingly taking it seriously for large, long-range aircraft, which can sustain the high quality of support equipment and safety precautions. It appears a viable option, but it needs a lot of engine conversion and airframe development work so don't wait up. Main problem for more down-to-Earth or small-scale use is handling safety; unlike LPG it is cryogenic, you do not want it squirting into your boots.
Gaseous hydrogen is no less practicable than bottled petroleum gas. That has several established niche markets. Quite why I hear nothing about making a changeover, I have no idea, perhaps it is just not romantic or large-scale enough for the chatterati to care. It certainly won't save the planet any time soon. But if I went caravanning, I'd be very happy to cook on bottled hydrogen.
Metal hydrides and similar clathrates have remained a lab curiosity, due to high cost. Maybe that'll come down, but unless and until it does, lithium batteries have stolen ahead.

Which brings me to electric. Quite why the old lead-acid based milk floats of my childhood died out is a mystery to me, and they weren't the only electric commercial vehicles around. Following the late Sir Clive Sinclair's failed C5 and Zike projects during the wilderness years, electric bikes were first to be resurrected by the modern battery revolution and are quite a thing among commuters these days. Today's electric cars have ranges of hundreds of miles. Electric is attractive for short-haul flights such as private/light and air taxis because the motors are very light and the modest battery weight associated with short range is not a problem. Several electric light planes and motor-gliders are already on the market, with many more clogging up the certification authorities' in-trays. Expect a gathering explosion in takeup, rapidly moving into the utility and light commercial sectors.
Electric is also attractive for densely populated areas, due to the lack of exhaust pollution; air taxis again, not to mention the newly-minted Personal Air Vehicle. But are urban point-to-point flights really practicable? As anything more than next-generation helicopters for the rich and powerful, regulators such as the FAA are pulling together a whole new technology framework for the necessary urban infrastructure, including smart traffic management, emergency landing sites, smart autopilots and so forth, all integrated in a seamless operating environment; I suspect we'll see hydrogen jetliners first.

Then, there will be the electric hybrids. These will likely fill the medium-range niches. But then, a fuel cell is basically a hydrogen-electric hybrid. Which is where I came in.
 
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In my opinion, in the short term, it is most likely we'll see aircraft being fueled on bio-ethanol made from waste food and sewage, as the current infrastructure can handle it (albeit with some changes). In the long-run, hydrogen seems to be the best solution, although the major problem is that it requires loads of energy to produce.
 
Where is the electricity coming from to charge these things? Greenies in Australia hate not only fossil but also nuclear and hydro with a passion. I'm all for not burning petrochemicals where it's avoidable (if only because they are so necessary to the plastics industry - in fact, in the novelization of ALIEN, the reason the ship is towing 2 billion tons of petrochemicals to Earth from God knows where is solely because of that; in that universe, the energy problem is long since solved), but there have to be sane limits on that when energy density is necessary in a particular application and the people who want to eliminate burning petrochemicals at all need to realize that the energy has to come from somewhere and it has to be available ALWAYS.
 
1000 cycles out of a Li-S battery. (lab scale)

~Practical 500Wh/kg appears on the horizon.

I hate to be a Debbie Downer but this prediction has been made so many times in the last 5 years and still we’re at 300Wh/kg.

If you read the book “Ignition” by John Clarke it details a 25year search for material (a mono propellant) that stored as much energy as possible, was safe for storage and its energy would be released upon command in a controllable manner…..Sound familiar?……They had numerous promising leads but one by one they found each failed on a detail point, normally safety related. Ultimately they didn’t come up with a single new practical solution.

The energy density of the best practical mono propellant, Hydrogen Peroxide (decomposed) is 2.7 Mj/kg and Lithium Thionyl Chloride (LiSOCl2) battery is 2.5 Mj/kg. An equivalent energy density for kero/air adjusted for gas turbine to electrical efficiencies is approx the same as TNT….. not known for a steady controlled energy release.

The battery energy density problem, just like the mono prop is extremely difficult and likewise it might not yield a solution.
 
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“GE Aviation and MagniX will perform integrated megawatt-class powertrain system ground and flight demonstrations to validate their concepts, and project benefits for future EAP aircraft configurations,” said Gaudy Bezos-O’Connor, EPFD project manager at NASA’s Langley Research Center in Virginia. “These demonstrations will identify and retire technical barriers and integration risks. It will also help inform the development of standards and regulations for future EAP systems.”

 

It looks like major airline academies are starting to take an interest in electric aviation.
 

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Looks like an established player is finally getting into the GA electric market. Could Cessna or Piper be next ?
 
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This article injects a dose of much needed reality into the electric aircraft revolution. The two major problems that I can see is that:

1. Many of these startups have vastly underestimated the technical and regulatory challenges of designing and certifying an electric aircraft and will thus fail.

2. Battery technology is not improving as fast as people were hoping it would. There are small incremental gains being made, but any huge leaps in battery chemistry is not possible for the foreseeable future.

This technical paper that studies the hypothetical development of an electric 19 seater also explains the enormous challenges involved. It's a bit long but well worth the read.


"At this point of the discussion, it may be clear that the possibilities for a successful introduction of a commercial, full-electric-propulsion aircraft in the short- or mid-term future are quite limited. Beyond certain niche applications, it is also doubtful that sufficiently strong business cases exist at the very low end of the air transportation market, at least without active support from political actors and policymakers"

"This paper shows that electric-powered civil air transportation over relevant distances would only become feasible with a significant increase in battery-specific energy and fundamental changes in operations"
 
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I suspect that the real "explosion" of technical advancement will come about if and when one of the more viable companies demonstrates profitability of the venture. Some of the mainstream aerospace companies (Bell, Airbus, and Boeing come to mind) were initially enthusiastically involved. I suspect that some financial reality of the technology efforts has since tempered their enthusiasm, although two of those mentioned are still moving forward.
 

A quick summary:

The aircraft will have a 1,100kg (2,425lb) battery pack and two electric engines, each putting out 429hp.

With today’s batteries the aircraft range will be only 85nm, though Tecnam hopes battery advances by 2030 will extend that range to 145nm.

Cruise speed will be 120 knots with a ramp weight at 4,086kg, compared with 3,700kg for the P2012.

It will enter service with Norwegian airline Wideroe in 2026.

The video below sheds a bit more light on the battery pack swap system Tecnam plans to implement.

View: https://www.youtube.com/watch?v=H4K5Zw5skfU&ab_channel=PixVideosProductionCompany
 

In the latest issue of Aviation Week, Embraer provided more information about their all electric 9 seat aircraft concept with a planned 200nm range. This version at the earliest could enter service around 2035.The batteries would be located in the nose to reduce turnaround times, with additional reserve batteries located in the rear fuselage. The aircraft would incorporate a glider inspired high aspect ratio wing for low drag. It would have contrarotating propellers at the top of the fin for high efficiency and low noise levels. There is also a hybrid version with a 500 nm range under consideration that could enter service around 2030 and it would be the least challenging design to develop.

The reason why Embraer is so conservative with their estimated entry into service dates is because they admit that battery energy density has to improve significantly by 2 or 3 times, for an all electric 9 seater to be viable. This is what they said about their rivals who plan to bring electric aircraft earlier to the market:

" There are few companies with the expertise we have in developing, certifying and supporting aircraft. We understand the concepts we are unveiling and that they will be actually viable by the time frame we are presenting. Companies presenting more aggressive targets are probably being overoptimistic."

So Embraer admits that the battery tech available today isn't adequate for a 9 seat electric aircraft with enough range to make it attractive to airlines. So how the heck is it that Heart Aerospace claims that they can put an all electric 19 seater with an impressive 250nm of range in service by 2026 ?

As I mentioned in another thread, the main problem with the electric aircraft revolution is that it was launched 10-15 years too early. The battery tech and infrastructure needed to support these kinds of operations is simply not there yet. Embraer is smart enough to realize that and plan accordingly.
 

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" There are few companies with the expertise we have in developing, certifying and supporting aircraft. We understand the concepts we are unveiling and that they will be actually viable by the time frame we are presenting. Companies presenting more aggressive targets are probably being over optimistic”

So Embraer admits that the battery tech available today isn't adequate for a 9 seat electric aircraft with enough range to make it attractive to airlines. So how the heck is it that Heart Aerospace claims that they can put an all electric 19 seater with an impressive 250nm of range in service by 2026 ?

The “start up” e-aeroplane, indeed hydrogen aeroplane sector is rife with investor fraud and deception. A fool and their money are easily separated. I fear when it collapses it will blight this business for years to come.

Volocopter have cancelled their SPAC and big aero company has just quietly sold out of a successful/expanding aero battery business which only a month or two ago they’ve very publicly supported;- Nerves are getting tested.
 
As I mentioned in another thread, the main problem with the electric aircraft revolution is that it was launched 10-15 years too early

Actually I would think that the main problem is that these electric aircraft are completely irrelevant, even if the technology does work as promised!

9 seater or even 19 seater aircraft flying short <100nm sectors are a rounding error in total aviation miles flown and carbon emissions.

In fact, factoring in eVTOL, which is more likely to harm than to help the environment (by creating new demand for inefficient commuter transportation by air compared to ground-based solutions)… the net result of electrification of aviation may well be negative.
 

There is some positive news to report, the revised prototype of the Eviation Alice moves closer to completion. The first flight is still scheduled for the end of December, but that is looking increasingly unlikely. With it's advanced fly by wire controls and pressurized cabin, this aircraft appears to be more of a replacement to the King Air than to the Cessna 402. The fact that it is quiet enough to operate from noise restricted airports even during curfew hours could be a big selling point. I could see this plane having more success as a corporate aircraft than a feederliner. It's too complex for small carriers like Cape Air. I also noticed that this aircraft has a revised cockpit configuration compared to the original prototype.
 

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" There are few companies with the expertise we have in developing, certifying and supporting aircraft. We understand the concepts we are unveiling and that they will be actually viable by the time frame we are presenting. Companies presenting more aggressive targets are probably being over optimistic”

So Embraer admits that the battery tech available today isn't adequate for a 9 seat electric aircraft with enough range to make it attractive to airlines. So how the heck is it that Heart Aerospace claims that they can put an all electric 19 seater with an impressive 250nm of range in service by 2026 ?

The “start up” e-aeroplane, indeed hydrogen aeroplane sector is rife with investor fraud and deception. A fool and their money are easily separated. I fear when it collapses it will blight this business for years to come.

Volocopter have cancelled their SPAC and big aero company has just quietly sold out of a successful/expanding aero battery business which only a month or two ago they’ve very publicly supported;- Nerves are getting tested.

I agree. There are far too many companies out there that have either completely underestimated what it takes to bring a develop an aircraft from scratch or are flat out lying to investors. And frankly, some of these investments firms should know better. There are NASA feasibility studies from 2016 that clearly state that electric aviation is not yet ready for prime time. Don't firms hire aviation consultants who analyze the feasibility of these projects before millions of dollars are invested ? I also wonder if the actual goal of these startups is to raise their companies profile enough to increase the chances of a merger or takeover. That way, even if the project fails, the original investors who founded the company make a huge profit. That's what happened with Eviation. Just before their first prototype burned up, they had a large investment firm acquire a 70% stake in the company.

 

9 seater or even 19 seater aircraft flying short <100nm sectors are a rounding error in total aviation miles flown and carbon emissions.
Not necessarily. If you look at one of the sessions (I can't remember exactly which sorry) included in the post I made earlier (repeated below), there is a case to be made for more smaller operations operating out of smaller locations and avoiding the big cities/major airports.

 
Yet another startup from the Netherlands that has very ambitious plans to build a small regional airliner. Range would roughly 341 miles. It will have a modular battery back that can be quickly swapped out when a newer one becomes available to make the aircraft future-proof. I wonder if the Dutch govt would financially support this project as a way of reviving their aerospace industry.


 
I wonder if the Dutch govt would financially support this project as a way of reviving their aerospace industry.
Hopefully the company investors are not a bunch of fokkers ! (I'll get my coat)
 
View: https://www.youtube.com/watch?v=QiNtLBLveeM&ab_channel=AVweb


An honest assessment of this aircraft and why it's not suited for the U.S market for now. Insufficient range is the big problem.

A bit off topic but there is also a 4 seat trainer under development in China with a purported 300 km of range, so longer flight times seem possible.

View: https://www.youtube.com/watch?v=DS3wXMESGkA&ab_channel=ElectricPlanesFlights


The manufacturer's website below:

 
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U.S. Army partners with eVTOL developer Beta Technologies / Flying Mag

DATE: January 31, 2022

BYLINE: Thom Patterson

Vermont-based Beta Technologies announced Monday it has won a U.S. Army contract to support flight testing of its Alia electric vertical takeoff and landing aircraft.

The partnership eventually aims to help the Army test specific military cargo and logistics missions for eVTOLs, while allowing Beta to accelerate development for both military and civil applications.

The Army contract isn’t Beta’s first partnership in the military sector. In 2020, it joined the U.S. Air Force’s AFWERX Agility Prime program, specifically designed to accelerate development of the emerging eVTOL industry.

“This partnership with the Army marks another important step in the military’s commitment to advancing and adopting sustainable electric aviation solutions,” said Beta founder and CEO Kyle Clark in a statement. “We’re gratified by the continued support of the sector, and this allows us to accelerate our development of Alia as an incredibly safe and reliable logistics aircraft for both military and civil applications.”

Initially, Army engineers and Beta’s team plan to evaluate how Alia might best be applied to specific missions by measuring its range, altitude, endurance, and payload limits.

About the aircraft
First revealed in 2020, Alia is Beta’s second-generation eVTOL test article. It’s a single-prop pusher with a 50-foot wing and V-tail. The aircraft achieves vertical lift during takeoff and landing from four fixed rotors. Alia is being developed for multiple roles, including cargo, medical transport, and passenger transportation. Beta says the aircraft will be capable of carrying a pilot and cargo—or four passengers—as far as 250 nm on a single charge. Maximum takeoff weight (MTOW): 6,999 pounds.

According to Beta, Alia set industry records last year, flying 205 nm on a single charge and reaching an altitude of 8,000 feet. The aircraft has flown multiple times between New York’s Plattsburgh (KPBG) airport and Beta’s headquarters at Vermont’s Burlington International Airport (KBTV).

About Beta Technologies
Although it doesn’t expect to achieve FAA aircraft type certification for Alia until 2024, Beta has already announced purchase agreements with UPS Flight Forward (NYSE:UPS) and Blade Urban Air Mobility (NASDAQ:BLDE). Also, Alia received the U.S. Air Force’s first airworthiness approval for a crewed eVTOL last year.

The privately held, venture capital-backed company announced last year it had raised $368 million in Series A funding, led by Fidelity Management and including Amazon’s Climate Pledge Fund. Beta also received an initial tech sector investment last year from UP.Partners, a group of serial aviation and tech entrepreneurs.

An electric transportation ecosystem
Beta sees itself as much more than an aircraft developer. It has plans to integrate its eVTOLs as part of an electric transportation ecosystem.

Based on the idea that electric aircraft will need viable infrastructure for charging batteries and other services before it can be fully successful, Beta already has started working to establish a multi-state network of charging stations designed to serve all electric vehicles, including cars, trucks, as well as aircraft. The company plans to build the stations across the eastern U.S., according to a map on its website.

At its Vermont headquarters, Beta has built what it says will be the first of many eVTOL recharging pads. The structure includes a landing pad for eVTOLs above the structure, which consists of crew quarters, a crew rest area, and a control center.
 

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