Category: Research

Even more H2

There’s a couple of Hydrogen related topics that are worth a moment. One is super conductors and the other is fire.

Heavy complex equipment like the magnets for particle accelerators use superconductors[1]. When there’s space and a need for powerful magnetics, materials with special physical properties, at extreme cold temperatures find a good use.

Talk of room-temperature superconductors is far from what it seems. Such a wonderful innovation is a million miles from any practical applications, if it exists at all. There’s no theory of high-temperature superconductivity, but there’s quite a few physicists who would like to find one[2].

Aviation researchers search for high temperature superconductors for electrical propulsion with extraordinary performance is on. The likelihood of success is low, and the timeframes are very long.

When an aircraft is flying at high altitude, the cabin altitude is maintained for the safety and comfort of passengers and crew. Air compressors, valves, sensors, and controllers make sure that cabin pressure remains at equivalent to an altitude of about 8,000 feet, and lower in some cases. So, any kind of simply flammable gasses or materials inside an aircraft cabin are a definite no no. It’s a big hazard.

In flight, the positive pressure should keep leaking gas out of the cabin. That is as long as the sources of fresh air for the cabin are keep well away from potential leaks.

That’s where Hydrogen gas can present trouble. Leaks can be common in dynamic Hydrogen systems. Storage tanks must be very strong to resist pressures and insulated to keep cold, at around –250°C. Escaping H2 gas is tiny. If that’s vented overboard then the risk of explosion or fire is significantly lowered. Knowing the exact flows of liquid or gas is a must.

However, if the gas finds its way into a pressurise cabin that basic option is limited. Not only that but detecting low concentrations of the gas in the first place is mighty difficult. Its odourless but at least Hydrogen isn’t poisonous.

The big safety issue is that the gas has a very wide flammability range (4 – 70% H2 in air mixture)[3]. Yes, H2 needs a spark to ignite. A typical aircraft cabin environment will easily provide that event. Dry air and static electricity will do it even if other sources will not.

To compound difficulties, if H2 does ignite, and not explode, then its flame may not be visible to the human eye. The flame is almost colourless. Certainly, not what most people think of as a gas flame. Gas and flame detectors could be installed in aircraft cabins and baggage compartments. Audible and visual alarms could be generated but what would be the associated crew actions?

All the above requires detailed consideration in aircraft safety assessments. The move away from prescriptive regulatory requirements means each specific aircraft configuration must be addressed. There are no generic lessons to learn from past aviation accidents and incidents.

Although, I think these puzzles can be solved it’s a huge leap from here to there.

POST: Yes, Hydrogen is not for every application. Small scale aviation is better served by electrification Five Hydrogen Myths – Busted. – RMI

[1] https://home.cern/science/engineering/superconductivity

[2] https://www.science.org/doi/epdf/10.1126/science.adk2105

[3] https://h2tools.org/bestpractices/hydrogen-flames

Electric Flight

Hype has its place. Being positive while buffeted by the inevitable ups and downs of life is purposeful and necessary. What’s not true, and might be the impression, is that electric aviation is easy. When forging ahead to build a future, that is not yet realised, there’s a need to maintain confidence. However, being blinded by the light doesn’t help when it comes to tackling difficult problems. Proof-of-concept is just that.

The big positives of electric aviation are the environmental benefits. Electric aviation is spawning many new types of aircraft and the possibilities of new types of operation. So, there’s no doubt that this is an exciting time to be an aviation enthusiast. What a great time to be in aerospace design and manufacturing. Here we are at the start of a new era[1].

My point is that high power electrics, and their control are not “simple” or intrinsically safe in ways other types of aircraft are not. I know that’s a double negative. Better I say that high power electrics, operated in a harsh airborne environment have their own complexities, especially in control and failure management. Fostering an illusion that the time between having an idea and getting it into service can be done in the blink of an eye is dangerous.

The design, development and production of advanced aircraft power distribution, control and avionics systems is not for the faint hearted. Handling large amounts of electrical power doesn’t have the outward evidence of large spinning mechanical systems but never underestimate the real power involved. Power is power.

The eVTOL aircraft in development deploy innovative design strategies. There’s a lot that’s new. Especially all together in one flying vehicle. Everyone wants fully electric and hybrid-electric aircraft with usable range and payload capacity. So, the race is one. Companies are productising the designs for electric motors of powers of greater than 10kW/kg[2] with high efficiency and impressive reliable. These systems will demand suitable care and attention when they get out into the operating world.

A 500kW motor will go up with one hell of a bang and fire when it fails. The avionics may shut it down, but everything will have to work smoothy as designed every day, not just in-flight but on the ground too. Suppressing an electrical fire isn’t the same as a conventional fuel fire either. To fix these machines the care needed will be great. 1000 Volt connections capable of supplying high power can kill.

Not wishing to be focussed on the problems but here I go. Another major problem is the number of qualified engineers, with knowledge and experience who can work in this area. The companies who know how to do this demanding work are desperately searching for new people to join their ranks.

Educators are starting to consider these demands as they plan for the future. Sadly, there’s not so many of them across the globe who are so foward looking.

The global aviation industry needs to step-up and train people like crazy. The demand for Subject Matter Experts (SMEs) is self-evident. That’s true in design, production, and maintenance. Post COVID budgets maybe stretched but without the big-time investments in people as well as machinery success will be nothing but an illusion.

POST1 : Or 150 kW motors when you have many of them going at once. Rolls-Royce Electrical Testing eVTOL Lift Motor | Aviation Week Network

POST 2: Getting ready Preparing Your Airport for Electric Aircraft and Hydrogen Technologies | The National Academies Press

[1] https://smg-consulting.com/advanced-air-mobility

[2] https://www.electricmotorengineering.com/h3x-new-investments-for-the-sustainable-aviation/

H2 is difficult

I mentioned Hydrogen as an option for aviation. The use of Hydrogen to either power jet engines or to power fuel cells to provide electricity is a real technical option. Although the person I was talking to was engaged in environmental work, they shrugged their shoulders when I mentioned Hydrogen. They were certainly not impressed by these possibilities despite our agreement on the urgent need for de-carbonisation.

I can understand why there’s a level of cynicisms. On my part, it’s like the X-Files[1]. Fox Mulder was the believer and Dana Scully the sceptic. Broadly, I want to believe.

Today’s, liquid fuels can be explosive in certain conditions. However, it takes a considerable effort to create the conditions whereby a devastating explosion can occur. The Boeing 747-100 that was Trans World Airlines Flight 800 (TWA 800)[2] exploded, broke up in the air and fell into the Atlantic Ocean in 1996. This was an example of a worst-case scenario. 230 people were lost in that fatal accident. Now, the ignition of a flammable fuel/air mixture in aircraft tanks is better prevented by design and operational procedures.

If Hydrogen is to be viable in civil aviation such hazardous conditions will be harder to prevent. A flammable hydrogen/air mixture can be ignited much more easily than conventional liquid fuels. Such dangerous situations can be prevented but the measure to do so will require robust design and stringent operational procedures.

Several development programmes are underway, making practical Hydrogen powered aircraft viable. A range of aircraft configurations are possible. From hybrid generator and electric motor set-ups to combustion-based propulsion. This work is moving from academic research into commercial possibilities.

There little read across between the behaviour of conventional hydrocarbon liquid fuels and liquid Hydrogen. This would be evident in any serious incident or accident scenario. Let us imagine the case of British Airways Flight 38, in 2006, a Boeing 777-236 that came down at the end of a runway at London Heathrow[3]. A significant amount of fuel leaked from the aircraft after it came to rest, but there was no fire. There were no fatalities.

The breakup of liquid Hydrogen tanks or plumbing in such a scenario would almost certainly result in a significant fire. The mitigating impact of that fire is the lightness of the gas. Instead of liquid fuel pooling on the ground, Hydrogen would burn upward. However, any explosion could be devastating.

So, for large aircraft design the provisions to protect liquid Hydrogen tanks and plumbing must be extensive and extremely robust. This would have to be maintained, as such throughout the whole operational life of the aircraft. These requirements would be onerous.

Keeping crew and passengers well away from Hydrogen infrastructure will be a must.

POST 1: Crashworthiness doesn’t get much of a look-in. Without it there’s going to be a problem over the horizon. https://www.ati.org.uk/flyzero-reports/

POST 2: At least for eVTOL aircraft some work is being done. https://ieeexplore.ieee.org/document/10011735

[1] https://www.imdb.com/title/tt0106179/

[2] https://www.history.com/news/twa-flight-800-crash-investigation

[3] https://assets.publishing.service.gov.uk/media/5422ec32e5274a13170000ed/S1-2008_G-YMMM.pdf

Over the Horizon

Reading Anne Corbett’s article on the Horizon Europe research programme[1], I’m struck by the one step forward and then one step backward walk that the UK is taking. The politics of the moment leaves a UK Prime Minister (PM) dancing on a knife edge. Afraid to fall to the right or to the left of his own party. Having been part of an extremely destructive period in British politics, Rishi Sunak is attempting to re-brand the Conservatives with a colour of nationalism that’s designed to be anything to everybody and as variable as the wind.

From the start of the year, Rishi Sunak has made five promises[2] on economy, health, and immigration. The one on the economy is steeped in blandness. This is presumably to claim success regardless of the situation in the run-up to the next UK General Election. If a PM, of any political party, didn’t want to grow the economy, create better paid jobs and opportunity across the country there would be something distinctly wrong. A wish is fine but what about actions?

I have to say that it’s good to see a UK PM that’s 20-years younger than I am. Particularly when the US is playing out a game of geriatric musical chairs. Russia being plagued with the politics of generations past. China’s building global influence. And to top it all the Earth feeling the impact of climate change like never before.

This why I have such difficulty in understanding Sunak’s attitude to working with our nearest neighbours and closest allies. We have more common interests now than we did in the 1970s when the UK first joined our local trading block. I’m sure the zealots can’t see this fact but undoing the last 40-years is not a good way to forge a future. We can do so much better.

Culham is known for its Centre for Fusion Energy[3]. Its work is collaborative. It needs to be, given the huge costs of working in the field of fusion energy. That’s the way the Sun generates its energy. Here’s an example of the UK being a focal point for European fusion research. Post Brexit, like the problems other research institutions have faced, some researchers returned to continental Europe.

The idiocy of de-Europeanisation serves no one. It’s a residual of discredited political thinking. A Government doesn’t need to advocate re-joining the European Union (EU) but they do need a whole new positive approach to working together with European countries and institutions. Research is at the core of our common interests.

[1] https://blogs.lse.ac.uk/europpblog/2023/07/28/will-the-uk-find-its-way-back-to-horizon/

[2] https://www.bbc.co.uk/news/uk-politics-64166469

[3] https://ccfe.ukaea.uk/

Past Earth

I wandered around the Natural History Museum[1] for an hour, or so this week. It’s one of the London Kensington museums that never loses its appeal. It’s a glorious place of assembled artifacts. At this time of year, it’s bubbling with children of all ages. Those ancient beasts that once strode the planet captivate and fascinate young minds. We can project all sorts of personalities upon them and know for sure we will never meet them wandering the streets.

I didn’t get to meet Titanosaur, one of the biggest animals to have walked the Earth but must go back and make sure I do. We share our planet with the remains of these giants. Luckily, we didn’t have to encounter them on the way to work in the mornings.

I like the reminder that human time and geological time are completely different spaces. We ponder the big news of the day over a tiny passage of history whilst the great expanse of life on earth sits quite in the background. Everything that made us, took billions of years to come to be.

Tracing the past, a couple of hundred million years isn’t much[2]. Yet, in one million we’ve come to dominate the planet as no other life has ever done before. We still have the choice as to our fate. Burning copious quantities of fossil fuel does seem foolish when seen in context. Will self-aware humans be a flash in the pan that comes can goes almost unnoticed by history?

Although, I don’t dismiss even remote possibilities when it comes to the unknown, the claims that non-human sightseers have been visiting us here on Earth does seem purely fictional[3]. There are several distinct arguments against such extraterrestrial alien holidaymakers.

Given the age of the universe, the coincidence of existence of multiple intelligent beings is possible, but they will certainly be separated by unfathomable distances. Even accepting the proposition that one day physics will provide a wizard transport system to cross those vast distances the needle in the haystack problem still means meetings may be extremely unlikely. Then there’s the arrogance that we presume such alien beings will have a shape, form and chemistry that has any meaning to us. Let’s face it, the abundance of life on Earth may be only a tiny range of what’s possible in the greater scheme of things.

No, I will continue to believe that there are rational explanations for lights on Salisbury Plain or deep in the Arizona desert. ET isn’t likely to be bothered with either. Unexplained aerial phenomena will continue to interest people, much as dinosaurs do but one is knowable today and the other may not be for generations, if ever.

[1] https://www.nhm.ac.uk/

[2] https://www.bbc.com/mediacentre/mediapacks/earth

[3] https://www.bbc.co.uk/news/world-us-canada-66320498?at_medium=RSS&at_campaign=KARANGA

Short-sighted

None of that comes cheap.

OK. Why are mini-nuclear power stations such an irrational idea? The industry is selling these untried, untested power station as completely unlike that which has gone before. A Conservative Minister has been echoing their marketing brochures.

Let me say, with power generation there are some basic realities that remain the same.

Fuel must be transported to power stations and waste must be removed from them on a regular basis. For coal, that was the reason for the sitting of large power stations in the past. For gas, there was more flexibility in location, but the costs of transportation still needed to be minimised. For such innovations as waste-to-energy plants, proximity to the source of waste presented a major problem. Neighbourhoods rarely invited these plants to be built close by.

Spreading the distribution of nuclear fuel and waste around the country doesn’t sound like a good idea to me. Cost of transportation are high. Safety is paramount. Security is always a grave concern.

Now, I understand the need for limited numbers large-scale nuclear power stations. They provide a reliable base load when the renewable sources of power are not available. The wind doesn’t blow.

Although, there are a variety of different international companies in the nuclear business the notion of a “free market” in the conventional sense is not a real prospect. The investments needed to be competent and meet regulatory requirements in the nuclear business are huge. Projects are there for the long-term. A whole working career of a nuclear engineer may be locked to one technology.

Experience has shown us that a goal of zero accidents rarely delivers a reality of zero accidents. These are complex engineered systems. It doesn’t matter if they are big or small the complexities remain. Yes, safety can be managed in a safety critical industry but there had better be preparedness for worst possible outcomes[1]. With these nuclear plants decommissioning and recovery from significant incidents of contamination must be accounted for in any design, implementation, and operation. None of that comes cheap.

Overall, in Britain there are much better paths to travel than the mini-nuclear one.

It absolutely astonishes me that, given the enormous tidal range of the Severn Estuary[2] we have never captured the energy of those waters. Equality in a nation, with a coast as large as ours, we have only ever dabbled in wave power[3]. Let’s have some genuine innovation. Let’s think like the Victorians and build for the long-term.

Why are we so incredibly short-sighted in Britain?

[1] https://www.bbc.co.uk/news/world-13047267

[2] https://en.wikipedia.org/wiki/Severn_Barrage

[3] https://en.wikipedia.org/wiki/Salter%27s_duck

Design

Forewarned is, fore armed.

Getting it right by design matters. If a designer gets it right, then everyone who follows gets what they expect. Why am I writing these words? Well, a dumb message has come up on my computer. What I call dumb is a message that tells me something has happened but gives me no clue as to what to do next. It’s about as useful as a chocolate fire guard as they say.

Messages like: “Operation failed with unexpected error” in the top right of the screen are not helpful. Pop-ups like this are an indication that this is not a good design. It’s a kind of catch all statement that means we haven’t got a clue.

The usual response to such a message is to start over again in the hope that this is a one-off occurrence. So, that’s what I did. Guess what the same situation occurred. Not having a better strategy available, I did the same again. Same result. Thank you, Microsoft Teams.

While I’m on about that company another small but annoying bugbear comes to mind. Microsoft Mail works well enough. However, a forced error happens every so often. I find that I’ve deleted a message that I’d intended to flag to remind me to do something. A hunt for the message usually finds it mixed up with the pile to be deleted. When the delete button and the flag button are next to each other this error is almost inevitable. Why did the designers do this foolish thing?

I’ll not beat up on Microsoft too much, given that just about every software company has one of two of these annoyances to ruin your day. Good job my personal safety doesn’t depend on this stuff, I say. So much for commercial off the shelf software in 2023.

A video scrolled up on my iPad. It was that man who likes to take machines apart: James May. A couple of million people have viewed his video titled: “James May’s Tesla Model S has failed![1]”

It’s a good reminder that designers need to think about situations that go badly as much as they need to think about them going well. Vehicles do sit around in garages. Not everyone is used every day. It’s not the fault of the owner if they do not run the vehicle for a while.

Electrification is great when everything works. However, a simple manual reversion should be available when the electrics are not there to do their thing. Afterall, we don’t yet have a reliable battery that lasts forever. The door won’t open because the battery’s flat is as useful as the message highlighted at the start of these words.

Oversights during the engineering design process happens when the pressure is to get a product to the marketplace as quickly as possible. Maybe this is one of them to look out for in future. I will not be smug. This sort of obvious when you know it flaw is as likely to happen in aviation as it is in other industries. Forewarned is, fore armed.

There are also the wonders of feedback. Having made a design error, it’s mechanics who often uncover it, figure it out and then find a fix. This is a shout out for easy and open reporting.

[1] https://youtu.be/NsKwMryKqRE

Titan’s fate

Firstly, condolences to the families and friends of those who perished in the deep ocean last week. This fatal tragedy took place in the full glare of the public spotlight. It’s time to give those affected time to grieve for their loss.

I will address the subject of vehicle safety in a technical manner. It’s immensely sad when what is known must be re-learnt in such a tragic way. By their nature, passenger vehicles that enter hostile environments will present high risks. There is always a likelihood of an event of significant severity as to cause injury. The imperative should be to reduce that probability as much as possible.  

The Transportation Safety Board of Canada (TSB)[1] has launched an investigation into the events that led to the loss of the submersible called: Titan. That organisation will do a detailed investigation into the reasons behind the accident that led to the deaths of five people on-board. 

There’s much conjecture about the factors involved in this catastrophe. News media and social media are awash with speculations. The facts are that contact was lost with the Titan’s support vessel and a catastrophic event took place[2].

What has come to light in the aftermath of this event is the public statements made by the driving force behind the Titan project. This has been contrasted with the those from the submersible community who spoke out on their concerns about the project.

My reflection on this information is to say that – safety starts at the top. If the entrepreneurs who promote these adventures are not literate, humble, and vigilant then outcomes are going to be negative. Those in leadership positions need to listen to those with expertise in their field of endeavour. Accepted, that it’s not the case that everyone will agree all the time about operational and technical risks but an open dialogue is vital.

I know that innovation often takes the path of trying, failing, trying again, failing, and trying again to eventually succeed. However, no vehicle should enter public service without sufficient proving.  Independent oversight adds value too. The cultural framework within which this happens shapes success or failure. That’s why there’s good reason for design certification. That’s to apply time and energy to extensive testing, applying recognised standards and listening to reputable expertise. At its best it’s an opportunity to draw on widespread experiences from the past – good and bad.

Systems that prove to be safe most often come about from those who take on knowledge, experience, and learning. Yes, this work is not free. It can cost much to go from theory to practice. When the impact of failure, when the outcome is tragic for families, loved ones and colleagues these expenses are not so large.

We must take every opportunity to learn from such fatal accidents to make them extremely rare. 

#Safey Management #SystemSafety #HumanFactors #SafetyCulture

[1] https://www.tsb.gc.ca/eng/medias-media/deploiement-deployment/marine/2023/m23a0169-20230623.html

[2] https://www.tsb.gc.ca/eng/enquetes-investigations/marine/2023/m23a0169/m23a0169.html

Weight

Projects aiming to electrify aviation are numerous. This is one strand to the vigorous effort to reduce the environmental impact of civil aviation. Clearly, feasible aircraft that do not use combustion are an attractive possibility. This step shows signs of being practical for the smaller sizes of aircraft.

Along the research road there are several hurdles that need to be overcome. One centres around the source of airborne power that is used. State-of-the-art battery technology is heavy. The combinations of materials used, and the modest power densities available result in the need for bulky batteries.

For any vehicle based on electric propulsion a chief challenge is not only to carry a useful load but to carry its own power source. These issues are evident in the introduction of electric road vehicles. They are by no means insurmountable, but they are quite different from conventional combustion engineered vehicles.

The density of conventional liquid fuels means that we get a big bang for your buck[1]. Not only that but as a flight progresses so the weight of fuel to be carried by an aircraft reduces. That’s two major pluses for kerosene. The major negative remains the environmental impact of its use.

Both electricity and conventional liquid fuels have a huge plus. The ground infrastructure needed to move them from A to B is well understood and not onerously expensive. It’s no good considering an aircraft design entirely in isolation. Any useful vehicle needs to be able to be re-powered easily, not too frequently and without breaking the bank[2].

Back to the subject of weight. It really is a number one concern. I recall a certain large helicopter design were the effort put into weight reduction was considerable. Design engineers were rushing around trying to shave-off even a tiny fraction of weight from every bit of kit. At one stage it was mooted that designers should remove all the handles from the avionics boxes in the e-bay of the aircraft. That was dismissed after further thought about how that idea would impact aircraft maintenance. However, suppliers were urged think again about equipment handling.

This extensive exercise happened because less aircraft weight equated to more aircraft payload. That simple equation was a massive commercial driver. It could be the difference between being competitive in the marketplace or being overtaken by others.

Aviation will always face this problem. Aircraft design is sensitive to weight. Not only does this mean maximum power at minimum weight, but this mean that what power that is available must be used in the most efficient manner possible.

So, is there a huge international investment in power electronics for aviation? Yes, it does come down to semiconductors. Now, there’s a lot of piggybacking[3] from the automotive industries. In my view that’s NOT good enough. [Sorry, about the idiom overload].

[1] https://dictionary.cambridge.org/dictionary/english/bang-for-the-buck

[2] https://dictionary.cambridge.org/dictionary/english/break-the-bank

[3] https://dictionary.cambridge.org/dictionary/english/piggybacking

UAP

….none of us are familiar with the variety in shape and size of flying machines currently being designed and developed for general use

There was a time when anyone raising the issue of the potential for an asteroid to send humans back to the stone age was mocked and derided. Anyone bringing apparent sci-fi plots into Parliament was jeered. Now, the subject is studied with intensity and considerable resources. The probabilities of Near-Earth Object[1] (NEO) impact is calculated, and small asteroid and comet orbits are monitored in detail.

Really bad films, like the one starring Bruce Willis have a lot to answer for. That space between fiction and reality gets filled with more than a few eccentrics and conspiracy theories. Trouble is that gives you, and me licence to smirk anytime cosmic occurrences come into discussion.

I must admit I like the term Unidentified Anomalous Phenomena (UAP) better than UFO. They are airborne phenomena, they are unidentified until we know better, and they are anomalous. Although, most reports are attributed to things that are known, even if they are rare events. Some are pooly reported and only scant evidence is avialable.

Discovering all there is to know about such airborne phenomena is a matter of both safety and security. However remote it might seem, part of this is the safety of aircraft in flight. I know of no examples of extra-terrestrial objects colliding with aircraft but it’s not impossible. I’m reminded of that classic picture of a bullet hitting a bullet in-flight and fusing together. It’s from the Battle of Gallipoli.

We might be entering a new era of transparency in the scientific study of UAP. This is a wholly good thing and highly necessary given the coming expansion in the number of air vehicles in flight. If Advanced Air Mobility (AAM) is going to do anything, it’s going to led to an increase in aviators and public reports. For one, none of us are familiar with the variety in shape and size of flying machines currently being designed and developed for general use. It’s likly that red and green lights moving through the sky at night is going to prompt public reports of the “unknown”.

Perspective plays a part too. A small drone close can look like a large airship at distance. As environmental conditions change so the perception of airborne objects can change dramatically. So, what we might observe and confidently attribute to be a drone or helicopter or aircraft in-flight is not always definitive. Applying disciplined scientific analysis to the data that is available has benefits.

Given that our airspace is likely to become ever more crowded, NASA’s study[2] of UAP has much merit. Recognising that resources are needed for this work is a lesson most nations need to learn. We can sit on our hands or giggle at the more ridiculous interpretations of observations, but this kind of reporting and analysis will be advantageous to aviation safety and security. It’s part of giving the public confidence that nothing unknown, unmanaged or uncontrolled is going on abover their heads too.

POST: UFOs: Five revelations from Nasa’s public meeting – BBC News

[1] https://neo.ssa.esa.int/home

[2] https://www.youtube.com/watch?v=bQo08JRY0iM