The Green Party, the EU/EASA and to a degree, ICAO, have made demands and set expectations about aviation’s contribution to the reduction of CO2 , as explained by the Tech Explore article:
“Aviation accounts for around two percent of global emissions of carbon dioxide (CO2), one of the major greenhouse gasses that causes global warming, according to the UN’s International Civil Aviation Organization.
Airlines transported 4.5 billion passengers in 2019, an increase of 4.2 percent from the previous year, according to the industry’s leading trade body, IATA.
Before the coronavirus pandemic broke out the industry was counting on traffic doubling in 15 to 20 years.
At the same time, it had promised to reduce CO2 emissions by half in 2050 from 2005 levels. Considering the expected increase in traffic, that works out a 90 percent reduction by flight.”
The 50% reduction in carbon emissions is being attacked on several different fronts. Flying green encourages the pilots to utilize the operational techniques to minimize the fuel consumption. The Air Traffic Control system, based on satellite, on board and ground computer systems, is also contributing to the target by minimizing time that the aircraft is in the skies.
Aircraft manufacturers are aggressively pursuing research to limit the fuselage’s inefficiencies, to find lighter structural materials and anything that will make their products greener. Some of these initiatives have already been deployed, but the effort to discover benefits continues.
A promising effort involves the examination of synthetic and bio jet fuels. The CO2 reduction available from these new sources of energy, but the challenge entails how to make production costs more competitive.
Alternative energy sources are coming to the fore, as demonstrated by the below articles about the BYE, NASA Maxwell and ZeroAvia aircraft (the first two are electric powered and the third relies on hydrogen).
Another advanced, promising project is The New All-Electric Plane, Alice, Will Do Almost All That The Public Wants.
George E. Bye, CEO of Bye Aerospace Bye highlighted that the flight test and certification process ha reached several key milestones:
- “In order to determine the most efficient propeller to maximise the overall efficiency Bye Aerospace has begun the next phase of flight test program for the two-seat all electric eFlyer 2 technology demonstrator.This program will collect the flight envelope engineering data for the three propellers being considered for the FAA-certified production version of eFlyer 2. The criterion for selection includes the propeller’s light-weight requirement along with the propeller’s aerodynamic design evaluated against the eFlyer 2’s flight training mission.”
- “Data from these flight tests will help our engineering team determine the most efficient propeller that will maximize the overall efficiency for the typical flight training syllabus requirement,,,The prototype Rolls Royce electric motor currently on the eFlyer 2 technology demonstrator has varying torque and a large RPM range with a relatively small size and cross-section compared to a conventional internal combustion engine. Therefore, more of the propeller length is available to provide thrust across a broad range of RPM. So we will be conducting flight tests with the various propellers over the summer against these beneficial and unique electric propulsion criteria.”
- “…the Critical Design Review for eFlyer 2, a significant milestone in the FAA Part-23 certification process, was completed June 5. “The Covid-19 pandemic has forced Bye Aerospace to communicate and collaborate remotely like everyone else, but we have continued to move forward in our certification process as safely, economically, and efficiently as possible,” he said. “During this series of flight tests in particular, we are closely managing the number of participants to observe social distancing and other recommended safety practices.”
NASA reports on this project:
Toward the end of 2019, more than 3 years later, NASA received the first full version of the X-57 Maxwell from Empirical Systems Aerospace (ESAero) of San Luis Obispo, California. It was still based on the Tecnam P2006T, an Italian 4-seat twin engine light aircraft. The first iteration had two 60 kW electric motors, but it was noted at the time that the final version of the electric airplane would have 14 electric motors and propellers, 12 of the motors being attached to the wingtips.
“For more than 70 years, this location has been home to many historic X-planes, or experimental aircraft, responsible for expanding the envelope and pushing the limits of aviation – a tradition that NASA is keeping alive through the Aeronautics Research Mission Directorate,” Matt Kamlet of NASA wrote.
“The X-57, which is NASA’s first piloted X-plane in two decades, is seen here in its final all-electric configuration, known as Modification IV, or Mod IV. This configuration will feature a skinny, high-aspect ratio wing, designed to boost efficiency by reducing drag in flight, and electric cruise motors with five-foot diameter propellers on the wingtips, to recover energy that would otherwise be lost to wingtip vortices.”
One of the unique features of the X-57 Maxwell is the row of 12 “high-lift motors and propellers” that run along the wings of the plane. They help the plan take off at industry-standard speeds. “These motors will activate during takeoff, spinning the propellers, and will deactivate during cruise mode, at which point the propeller blades will fold in to the nacelles, as seen in two of the above images, reducing drag.”
One thing NASA is using the X-57 for is to help create certification standards for electric aircraft.
“We caught up with Val Miftakhov, founder and CEO of ZeroAvia, a company that’s betting heavy on hydrogen in the aviation space. Where some are focused on the short-range eVTOL air taxi market, ZeroAvia is getting started on mid-range regional flights by developing and retro-fitting fuel cell powertrains to small, 10-20 seat passenger planes. The company says it can reduce costs by as much as 50 percent on this kind of operation.
Can you sum up how ZeroAvia came to be and where you’re at right now?
My background is in physics, management consulting, Google, Uber, then I started my previous company in the electric vehicle space, eMotorWerks – we became the largest vehicle-to-grid integration company out there. That company was acquired two years ago and that’s when I started ZeroAvia.
I’m a pilot myself, a private pilot flying airplanes and helicopters, so it’s a personal passion for me. Having spent a number of years in the zero-emissions transport space, it made a lot of sense to focus on aviation, look at what sustainability in aviation might look like and how we can bring it to the world.
We thought early on about how we can address the large existing segments of aviation. There are a lot of companies focusing on urban air mobility, flying cars and so forth. We thought that these are all great projects, interesting technologically, but they wouldn’t do anything to our emissions footprint in the existing aviation segment. If you’re flying from Melbourne to Sydney, that’s not going to be helped by any of the flying car companies today.
That was the motivation: how we can start bringing those segments into the zero emissions world. Once you do the math, and start trying to understand what technologies you can use to get there, pretty quickly you’ll zoom in on hydrogen-fuel-cell-based powertrains. There’s nothing else that really works that well.
Batteries are too heavy, biofuels cannot scale, hybrids with turbine engines don’t really make sense – you’re increasing the complexity of the powertrain for relatively limited gain on longer trips.
What remains are hydrogen-based propulsion methods. One is hydrogen-electric, and that’s what we’re doing with fuel cells. Another is synthetic fuel, which uses the same turbines as you have in aircraft today, but produces fuel from hydrogen into synthetic liquid jet fuel. The latter is more expensive, requires more energy and still has all the disadvantages of liquid fuel burning: particulate emissions, nitrogen oxides, turbine engine maintenance and so forth.
Do you see any specific barriers to certification for hydrogen-electric powertrains?
Well, the main barrier really is the lack of standards for these new powertrains. If you build a new piston engine or a new turbine engine, you have a testing book. You can show up to the certification authorities and they’ll pull out the book and say right, these are the tests we need to run, this is how long we need to run your engine, under these parameters, and everything is described. When you design and test the engine before the certification, you’ll know what to expect.
From a technology and physics perspective, there are no physical barriers. Val Miftakhov
In the case of new engine types, and that includes battery-electric and any others that aren’t traditional engines, and definitely hydrogen-electric, you don’t have a book. So first and foremost, you need to work with the regulators to write the book. That’s what we’re doing now already with the FAA in the US and the CAA here in the UK, so that in 12-18 months, we can show up with a system that we think can be certified, and there will be a book against which it can be tested.
So this is the main barrier. From a technology and physics perspective, there are no physical barriers.
Today, on the ground, hydrogen fuel cell vehicles are a real thing. Since about five years ago, Toyota started pushing hydrogen cars onto the market to regular consumers, with fueling and everything. So there’s now maybe 15,000 hydrogen vehicles in circulation on the ground worldwide, plus maybe 30-35,000 material-handling equipment. Not in the air, but the technology, the storage and utilization of hydrogen in those vehicles is similar to what you have in the air. Fuel cell tech with compressed hydrogen storage that you produce electricity out of.
In our conversations with the FAA and CAA, hydrogen is something they find to be more conceptually similar to the other chemical fuels, compared to batteries. In the hydrogen-based powertrain, you have fuel storage where fuel is kept separate from the oxidizer – the air – at all times, except for a very small amount that flows in the fuel cell. That’s versus batteries; what makes people worry is that the fuel and oxidizer are all in one package, impossible to separate if something goes wrong. So you have these runaway effects in large-scale, high-energy-density batteries that are very hard to contain. Once a battery fire starts, for example, it’s very difficult to stop.
So it’s conceptually quite different and, if anything, the certification authorities are unclear about how to deal with batteries as opposed to chemical-based fuels like hydrogen.
Then you look at things like ignition temperature of hydrogen – much higher than jet fuel. It’s practically impossible to pool hydrogen in one place, or maintain a concentration in the open air. It’s very lightweight, it escapes very quickly. Jet fuel and aviation gasoline have vapors that are really heavy, and they concentrate around the leaked fuel. Those can ignite much more easily.
So there are some fundamentals for hydrogen that are actually better than jet fuel from a safety perspective. Of course, we’ll need to do the right amount of testing and so forth. But we’re pretty optimistic.
The interview continues with considerable technical opinions.
The importance of this initiative is demonstrated bythis letter from a wide variety of aviation interests requesting that the European Union “prioritise specific decarbonisation initiatives in their allocation of future COVID-19 recovery funding”
 SEE RESUME AT THE END OF THIS POST
Founder & CEO
ZeroAvia is building the World’s first practical zero emission aviation powertrain. Started by the serial entrepreneurs in EV space, the company initially focuses on 10-20 seat regional aircraft with 500-mile range. ZeroAvia’s unique approach results in 4x lower fuel and engine maintenance costs, with no harmful emissions.
eMotorWerks is the market leader in Smart EV Charging. Its virtual power plants built from thousands of electric vehicles help reduce strain on the grid, integrate more renewable generation, and make money for the EV drivers. From Amazon best sellers to best-in-class smart phone and smart home interfaces, eMotorWerks leads the industry in responsible and profitable integration of EVs into the electrical grid
Helping top companies worldwide on the matters of strategic importance to them – focus on High-Tech industry, Business Unit Strategy, Marketing & Sales (new product introduction, customer segmentation, pricing, etc), Digital Media
Experimental Physics. Worked at Stanford Linear Accelerator Center on one of the two most important projects (at the time) in high energy physics.
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