eVTOL taxis: The tight-rope walk of trade-offs to reach commercial success

This is my 4th post covering the exciting world of eVTOL Urban Mobility and its emergence as a viable transport option. Here I cover various trade-offs that must be considered by the 170 or so companies world wide that are currently developing such vehicles…

Evening clouds above

One of the most exciting elements of the emerging eVTOL taxi industry is just how diverse the designs and concepts are showing up to be. The use cases that they are intending to serve have up until very recently been technically unfeasible, and with no successful baselines to refer back to, creativity and experimentation rule the day. You would expect that over time designs will become more and more homogeneous, as has happened with the aerospace and automotive industries. However, until then, we have many years of varying designs to look forward to as many organisations seek to find the magic formula to ensure that they are more effective than their competitors.


Unfortunately, as with everything in life, an optimal design will come from effectively balancing between competing requirements, you can’t have everything. Below I explore some of the more pertinent of these necessary trade-offs.

Take-Off Efficiency Vs Horizontal Flight Efficiency

On the one extreme you have a design similar to a helicopter, with vertical facing rotors, this concept is very efficient at providing vertical lift, and hovering in one position. However, when it comes to flying in a horizontal direction, this design is very inefficient.

On the other extreme you have a fixed wing design, similar to a Harrier Jump Jet, this is very maneuverable and efficient when in forward flight, but takes a lot of skill and energy to enable vertical take-off. Not to mention produces a lot of noise during this process, as shown in the video below:

Although developments in electrical propulsion systems mean that more advanced concepts can be used to power this next generation of vehicles, thus leading to quieter and more energy efficient solutions. The vertical vs horizontal trade-off is unavoidable. Inherently, solutions optimised for vertical lift will be more suited to shorter journeys and more frequent landings, but will tend to be more noisy and slower in horizontal flight. Those designs optimised for horizontal fight will tend to have noisier and more energy intensive take-offs. According to Uber’s elevate white paper: Uber Elevate, an eVTOL vehicle can expect to use the same amount of energy to take-off and land as it would need to travel horizontally for 50 miles.

rotor fixed wing

Performance & Efficiency VS Ease of Maintenance and Certification

One way of countering the vertical vs horizontal trade-off is to design a vehicle with propulsion systems that rotate into optimal positions for both modes of flight (see example above). Several eVTOL developers have opted for variations of this solution. The draw back of this approach is that with significantly more moving parts and mechanisms to control, there are a lot more things that can go wrong. This will mean increased frequency of scheduled maintenance as well as the need for more replacement parts. This also means that the vehicles will be more complex and expensive to pass through certification. Estimates can be taken from the aerospace industry, but judging by the variations in designs it is not yet obvious where the sweet spot is in terms of efficiency of flight operations vs cost of maintenance and certification.


Battery Service Life vs Battery Weight & Logistics

Lithium Ion Batteries are happiest when 50% charged, and least happiest when 100% or 0% charged. In general the more that they are subjected to 100% or 0% charge the quicker they will degrade and need to be replaced. Volocopter estimates that the battery will consist of up to 75% an eVTOL vehicle’s operating costs. Most appliances (including Tesla’s vehicles) get around this by not allowing you to charge up to 100%, or run down to 0%, but this means your battery capacity needs to be bigger than what is actually accessible. As batteries tend to be heavy, this becomes an issue in vehicles that need to escape the Earth’s gravity. Thus battery size and capacity needs to be carefully matched against likely journey times.

There is an added complication in that fast charging these batteries also causes them to degrade more quickly. An option can be to simply swap out batteries at service stations, and then charge the spares at a slower rate. This means that more batteries need to be held in inventory, complex mechanisms and fastenings need to be utilised to enable them to be switched, and inspection and certification requirements will become more complex.

overloaded bus.jpg

Carrying Capacity Vs Noise Pollution

This is a particularly tricky trade off. As seen with traditional commercial airliners, the most economic and cost effective method of transporting people in the air is to build a fairly large aircraft. This improves the mass efficiency, as the increase in the weight of the aircraft is less than the increase in weight carrying capability of passengers and their luggage. Unfortunately however, the power required to create lift increases at a greater rate than the increase in passenger weight. This isn’t so much of a problem when you can take a long take-off, utilising the lift efficiency of a fixed wing, but when you are relying on rotors or turbines to create lift, this large increase in power requirements means noise increases very quickly. This problem is compounded when utilising electric power, as it means more battery power (and therefore battery mass) is also required. Thus there is a direct conflict between carrying capability and the economic benefits of  carrying more passengers in one vehicle, vs the power and noise that is necessary for take-off and landing. Once again, the use case of the vehicle will need to be carefully considered to ensure that an optimal balance is achieved.


Population Density & Demand Vs Certification & Regulation Requirements

Basic logic dictates that demand for transport services that will drastically reduce travel times will be in higher demand in areas where there are higher population densities, where people tend to be more time poor, and where there is congestion problems with incumbent substitute travel options. However, as specified by Volocopter in their recent white paper Volocopter White Paper certification requirements are 100 times more stringent over cities than they are over rural areas. This is without considering that before too long there could be traffic jams in the sky, and thus there will likely be tariffs to cover the cost of directing and managing air traffic in densely populated areas. Another factor to consider is that in densely populated areas you are never far away from people, great for potential customers, but not so great when it comes to noise pollution and regulations that come with it.

Considering this, it is understandable to see small businesses such as Esprit Aeronautics covered in my previous blog artical: eVTOL, interview: Simon Scott. Founder and Owner of Esprit Aeronautics choose to operate away from cities in under-served rural areas. However, the main players in this sector are developing much more expensive vehicles that will need to be utilised more productively than serving rural areas will likely allow. Thus a strategy to overcome the barriers of operating above cities will be necessary.


Market Segment vs Public Acceptance

The above mentioned Uber Elevate paper estimates that initial flight costs will be approximately $150 for a 50 mile journey. In energy and maintenance terms, it is likely that half of that cost will be just for take-off and landing. Thus there will be an initial $75 levy needed to break even before the journey duration is even considered. Over time Uber expect the cost to fall significantly to just $25 for a 50 mile journey, but in the near time it is clear that the service offering will need to be pitched at wealthy clients willing to choose a more expensive alternative to existing services in order to save journey time.

The problem here is that geographical locations where high net-worth individuals live tend to also to be areas with the least noise pollution, while also being the most aesthetically pleasing. Thus it will be harder to gain acceptance for services that bring easily noticeable noise pollution as well as potentially become a blot on an otherwise beautiful landscape. Further to this, if only 5% of the population can afford to use such a service, then the other 95% of the population are likely to be unhappy to be disturbed to enable the ‘privileged few’ to live a life of increased convenience. In nations where  introducing legislation tends to be a democratic process, introducing eVTOL services under the above circumstances may prove to be a challenge.


First Mover Advantage Vs The Curse of the First Mover

First mover advantage will enable an organisation to work with certification agencies, which will in turn mean that legislation will naturally lean to cover their specific products. It will give you a head start in building a portfolio of qualified materials, processes and operating criteria, so you can tailor these to your business’s strengths. Pilots will be trained on your products and get used to flying them. You will get first option on licencing of areas (assuming air traffic control will be restricted by licencing areas and capping amount of traffic). You will also get a chance to establish your brand while there is less competition.

However, especially considering all of the uncertainties and trade-offs above, committing to capital investments when the industry is young means you are also committed to a strategy that carries a higher risk of failure than for a more mature market. Organisations that come late to the party can gain valuable insight from the first movers’ lessons learned, they can wait to see what concepts and business models become the most successful, and then simply target to beat these early leaders in order to gain market share. The first movers may find it hard to react to these late entrants as they have already spent their capital to develop a market which will likely be unprofitable during its early years.

The same can be said for infrastructure, early investment gives you a likely cost advantage as competition is low, and a head start in setting up key hubs. However, there is risk that as the sector develops, customer’s needs will also develop, and the original locations and architectural designs become quickly overlooked by newer options.

This is not to say that the early movers are destined to fail, but history doesn’t favour their chances. They will need to maintain agility to ensure that they adapt with the fast moving market and it’s regulations.


In my next article I will look at a couple of the first movers in this emergent market, assess the strategic decisions they have made with regards to the above trade-offs, and evaluate what I feel are their strengths and weaknesses…


So are we finally going to live like the Jetson’s??

Human’s have been buzzing around in flying cars since before we landed on the moon, in cartoon form at least. However, if the hype is to believed then maybe 60 years after the first Jetsons episode, we in the real world are finally catching up…


Although I’m not old enough to have witnessed the first showing of the Jetsons, which aired in September 1962, I do fondly remember their 80’s shows. The life and times of the Jetson family was given to us as a futuristic alternative to the Flintstones, and the notion of flying cars as well as other futuristic inventions left a lasting impression upon me.

However, despite the optimism that us pre-millennials carried with us through the 80’s, it didn’t seem to translate into reality. Our wide eyed vision of the future was most likely fueled by our parents witnessing the moon landings when they were a similar age to us, together with the emergence of the computing age; which would seemingly make anything possible. I remember reading children’s books that were telling me by the year 2000 we would no longer be using petroleum fueled cars. I also remember watching Back to the Future II in 1988, which told me that by the time I was 35 I would be whizzing around on a flying hover-board.

BTFII Hoverboard.png

You can’t deny that the impact that the likes of Mark Zuckerburg has had on our lives is both significant and unpredicted. But in terms of tangible inventions, when compared to what was being predicted, it’s certainly a case of must try harder. Sure, I love the fact that I can make my face look older than it really is just by using a special app, but how come it still takes me 24 hours to get to Australia? and while I’m at it, how come my journey out of London for a weekend retreat now takes longer than it did for my parents at my age??


Well documented studies have shown that social media isn’t actually that social, and with climate change becoming ever more of an issue, the challenge of physically connecting people seems to be becoming much more difficult than the now solved challenge of virtually connecting people.

I mean, if you have a vacuum cleaner manufacturer has decided that they can make better electric vehicles than incumbent vehicle manufacturers, then surely the industry is in need of a shakeup?


Well, finally we might be getting there… following on from Elon Musk’s foray into the electric vehicle market with Tesla, companies are starting to take this one step further and combine electric propulsion with air travel.

lilium jetThis year has seen a marked increase in media exposure for where we hope the next generation of aircraft will take us. The 2019 Paris Airshow displayed several electrical powered concepts, including an offering from both Airbus and Boeing. Roland Berger, an aerospace thought leader, have stated there are now 170 different ‘e’planes globally Roland Berger Study. Of these 170, there are two German based start ups, one who is aiming to serve London with air taxis by 2025 Lilium Jet’s 2025 target, and another who is aiming to go one further and provided automated flying taxis. I challenge you to watch the video clip below and not get excited…

Having been rather blown away by these claims, my imagination was quickly kicked into overdrive with what possibilities and opportunities such developments will bring; from transformational commuting experiences to exciting employment opportunities. However, as the saying goes, once bitten twice shy. With the broken promises of Marty McFly and Doc Brown still fresh in my memory, I thought it only right to investigate further into this fresh and exciting sector. Just how real are these claims?

I will be sharing my findings upon this blog, so you will be the first to know. Starting with an interview with a business owner who is developing a manned eVTOL (electrically powered vertical take-off and landing) vehicle, which I will post tomorrow…


How to create positive environmental impact through consumer demand..

As consumers become ever more environmentally conscientious, giving them access to the data to help make informed spending decisions would force businesses to tackle sustainability.  The emergence of block chain and the Internet of Things is making this concept a real possibility.


Today there is much concern for our Earth’s environment, and climate change appears high on many peoples’ agendas. The media shows us that high profile protests are increasing, such as those from Extinction Rebellion this year in London, and the rousing words from Greta Thunberg in late 2018.

Sir David

Sir David Attenborough has also helped increase the world’s awareness of what impact  our consumption habits are having upon the planet and nature around us. The Google Trends chart below shows the dramatic increase in searches for the term “Plastic Recycle” immediately after Sir David’s Blue Planet episode showing how single use plastics are hurting our planet. Approximately one year on from the first broadcast of this episode GlobalCitizen.org reported that it has changed the lifestyle of 88% of viewers. Fast forward to Spring 2019, and Attenborough’s hard hitting new documentary episode on the effects of climate change is set to have a similar impact.

Trends Plastics

Despite all of this attention that the subject is attracting, it dawned on me some time ago that currently there is scant information available to enable environmentally conscious consumers to make informed decisions. What products have high carbon footprints? By making some small changes to consumption habits, how can a person’s carbon footprint be reduced? Food packages have nutrition information on them, why don’t we have something similar for climate impact? While considering these questions, I came across the excellent website and app gikibadges.com which allows you to scan bar codes of supermarket items to find out how they impact the environment and your personal health. I would strongly encourage all readers to download and use this app.


Giki is an exceptional tool and a step in the right direction, however I feel that the business world could do a lot more to help us and them. For me, an optimal solution would combine the world’s obsession of social media, the internet of things and block chain. This solution would give people a user profile that updated their carbon footprint with their spending patterns. These profiles could be kept private, or for advocates who are proud of how they have reduced their footprint, made public. This would create some friendly competition between consumers, which in turn would lead to further carbon footprint reductions.


How would such a tool create revenue? Each user would be a strong climate change protection advocate. For each of these users there would be data available showing all of their spending patterns. The environmentally conscientious business could access this data and propose alternative purchases to users to further reduce their carbon footprint. This creates a virtuous cycle, where environmentally friendly suppliers are selected ahead of others, causing more suppliers to follow suit. It also creates a system whereby those businesses that place sustainability high on their priorities have the chance to be rewarded for it. On the other side of the scale, suppliers who were unwilling to participate would eventually be overlooked by consumers, forcing them to adapt or lose market share.


With block chain now becoming widely used, it will soon be possible to track transactions throughout a product’s entire supply chain, and thus claimed carbon footprint values can be verified. While the Internet of Things will allow us to upload all purchases onto our profiles immediately. Meanwhile there are also some forward thinking businesses that are now providing ‘extra-smart’ electricity meters that show you usage of each individual appliance. It doesn’t take too much imagination to see a world where our carbon footprints are measured and recorded real time, and businesses are able to see where they can help us make improvements.

The question I have is: Who will move first to take advantage of this? A supermarket and social media partnership? Amazon perhaps? I will be watching this space..

Review of Coursera.org, online management and energy courses

This is my first of many intended posts that will cover my reviews of courses and other educational content that I have used or read. This particular post covers several of the online courses provided by coursera.org that I have completed. Reflecting my aspirations beyond Sloan, these have been a combination of management and energy courses. 



Managing the Company of the Future. Created by LBS | Julian Birkinshaw.

managing the company of the future

This course was fresh and insightful while being light enough to easily digest. It covers the different organisational structures used by modern companies, ideals used to motivate staff, and common problems encountered by businesses due to inappropriate organisational structures and processes. It is worth saying here that Julian is a very highly regarded professor as well as the deputy dean of London Business School, so considering that this course is free I would strongly recommend it.


The Manager’s Toolkit. Created by Birbeck University of London.

managers toolkit

This course for me was not so crisp, there were some useful areas covered, such as conducting interviews, giving feedback, and facilitating meetings, however the content seemed a little tired and dated. I would strongly recommend the Managing the Company of the Future course ahead of this., as they are both free.


Global Energy and Climate Policy. Created by SOAS University of London.


This course was fairly decent, it offered a lot of reading material around the subject, and went into some detail as to how energy policy is changing around the world, and what structural changes are necessary in order to ensure transition to a sustainable society. My only gripe is that because it is political in nature, the content is fairly high level and conceptual in nature, although that said there are some quote insightful interviews etc so if you are interested in this subject I would recommend you having a look.

Our Energy Future. Created by the University of California San Diego.

our energy future

I have saved the best until last here, I really, really enjoyed this course and found the content incredibly informative. I would recommend everyone at least watch the opening two videos on the first module, these were superb. The only downside to this course was it was quite time consuming – I think it may have taken around 15 hours of my time by the time I finished, and this is without considering any of the written essays (if you opt to take them – you can just opt to watch the video content).

Key take homes for me were:

  • The world’s population increase over the last century or so is due to a dramatic increase in agriculture productivity, which in turn is due to harnessing the power of fossil fuels. Without these fuels or alternatives we will not even come close to sustaining the world’s current population, let alone future forecasts.
  • Fossil fuels (especially oil) are so energy dense and cheap to process into a usable substance, that it is incredibly challenging to create alternative energy sources that are viable alternatives. For instance, modern batteries contain several times less storage capacity as the same weight and volume equivalent of oil. This is why fossil fuels are so popular and hard to remove from everyday life.
  • Several bio fuels are being developed that will extract CO2 from the atmosphere, meaning that there use will actively reduce CO2 in the atmosphere over their total lifespan. These products can be used with existing oil refinery infrastructure. Considering this, we may find more cars move across to this type of fuel rather than moving to completely electric.
  • Approximately 40% of today’s global warming is due to ‘black carbon’ which is released into the air when burning wood and other materials used for cooking in the developing world. Black carbon only stays in the atmosphere for approximately 2 weeks, so if we could provide alternative cooking methods to the developing world, we could dramatically reduce global warming. Now there;s food for thought…



500 words to make the world a better place…

This post shows my response to one of the LBS Sloan MSc scholarship application essays that I completed. Plus some additional thoughts on the subject topic. The title of the essay given was:

Describe an innovative solution to a worldwide issue of your choice (Max 500 Words).


My response to this was:

A pressing issue facing the world today is; how does humankind supply power to its planet without making it uninhabitable? Solving this problem is gaining momentum, as demonstrated by the international collaboration that enabled the 2015 Paris Climate Agreement.

This is reducing the use of fossil-fuel generated power; thus supply of ‘traditional’ electricity sources is falling, while total electricity demand increases due to a reduction in transportation’s dependency on oil.

As a result, global solar energy supply is predicted to double every 18 months, while in the U.K (representative of the global average) wind power increased by 45% from 2016 to 2017.


Despite these changes, forecasts beyond 2030 show significant power supply deficits without the use of fossil fuels, and this is before considering that transportation embracing electrical propulsion could eventually double demand.

The erratic nature of renewable energy supply is an unquestionable problem. To mitigate supply shortfalls using only ‘clean’ sources would necessitate system capacities to be far in excess of demand. An alternative solution is to have traditional energy supplies used as back up, such as the U.K’s capacity market, but this is inefficient and contravenes climate change policy.

Research has shown that energy systems can be significantly optimised by both reducing supply fluctuations and introducing electricity storage into the distribution network.

To visualise how a system can be optimised, consider energy as inventory. Distribution systems such as those within the supermarket industry have managed to minimise inventory through intelligent location of intermediate storage facilities, together with increasing sources of supply.

Energy supply variations can be reduced by blending sources (solar and wind often have negative correlation) and by varying sources’ geographic locations. In addition, energy storage offers great potential. Storage technologies are in their infancy, as of June 2017 only 1% of U.K electricity demand was met by storage, but predictions estimate this may increase to 20% by 2022.

What is most urgently required now is a universal understanding of the most efficient energy supply system. Currently developments are often being progressed independently of one another, based on what individuals think will offer the industry the most benefit (and thus return on investment).

The World Energy Council predicts that energy system optimisation will enter mainstream thinking within five years. This approach is illogical; successful projects require completion of system design prior to implementation. Why would implementation of unprecedented energy system changes be any different?

This generates two difficult questions: What is the most efficient supply system? How can collaboration be co-ordinated to achieve this model? Difficult yes, but not impossible, and obtaining the answers could be key to turning a clean energy deficit into an exportable surplus.

An innovative way to develop answers could be through a high-profile competition similar to Google’s Lunar X prize. Google’s competition “sparked the conversation and changed expectations”, by encouraging exploration of the boundaries of knowledge, and sharing discoveries.

If incentives and prestige can help with cheaper space travel, couldn’t a similar approach work for energy system optimisation, and therefore climate change?

[Word count: 500]

panda solar

Now first of all let me start by saying that I didn’t win an award for this particular essay submission, however it was the one essay that I found the most thought provoking and engaging.

My professional career to date has not given me any exposure to the energy industry, and thus quite a significant amount of research was needed. This in turn has resulted in  this essay being quite an educational piece for me, and has got me to thinking about what the possible answers to the two ‘difficult questions’ could be.

The first question: What is the most efficient energy supply system?

Of course with limited technical knowledge it is not possible for me to answer this with great authority, but I can use what experience I have garnered from other industries to presuppose what might be effective.


I did briefly brush over this in my essay when referencing supermarkets distribution systems, which in turn are often used as a simplified analogy to describe a Kan Ban / Just In Time or Lean production system.

A supermarket maximises the quantity of products it is able to supply to its customers, while at the same time minimising the inventory of said products that it holds. It has a small amount of storage within each store, on the shelves. These shelves are replenished from stock that is held in larger quantities at the rear of the store, which are in turn replenished from a local distribution warehouse. Each one of these storage areas will be designed so that it can hold the minimum amount of buffer stock to ensure that there is a constant supply to meet consumer demand.

In addition, each supplier will likely also have a buffer stock quantity ‘on the shelf’ at either the production source or at a distribution centre, which will enable them to react to fluctuations in demand and supply supermarkets immediately as required. The supplier will produce to replenish this buffer stock, allowing a stable production output to meet peaks and troughs in demand.

distribution system

This is a very simplified view, but also consider that a supermarket distribution system must supply thousands of varying products to thousands of customers with various consumer preferences. With an energy distribution system, every consumer has exactly the same requirements, albeit in different volumes. Surely optimising an energy distribution system must be easy compared to a supermarket equivalent? This leads onto difficult question number 2..

The second question: How can collaboration be co-ordinated to achieve this model?

A significant difference between a supermarket chain’s distribution system, and a national energy supply distribution system, is that the supermarket chain is likely to have one organisation leading and co-ordinating operations. Whereas an energy distribution system will consist of several large energy producers, separate organisations responsible for the energy distribution network, and often separate organisations responsible for supplying said energy to the end user. Each of these ‘players’ within the market will be competing against one another to get a larger foothold in the market. Thus collaboration and joint strategy will not be a natural step.

A similar example is the pharmaceutical industry, where traditionally firms have been very secretive of their development activities, which often means duplication of the same research, and thus inefficiencies across the sector as a whole. Squeezes on firms return on investment margins in recent years has resulted in them starting to collaborate on research activities and data. This is certainly an interesting prospect, and if successful could be emanated by many other industries, not least energy supply.


A more mature model that could perhaps be successful has been used for several decades within an industry that is very close to my heart; The Space Industry. Within this industry, most developed nations have a central body (US: NASA, Japan: JAXA, Europe: ESA) that analyses the most effective areas for investment, and develops a coordinated strategy for the whole industry based upon the results of this analysis. It then utilises third party organisations to supply much of the ingredients needed to implement this strategy – be it R&D into new materials and technologies, supply of spacecraft equipment, or bespoke software for specific applications.

This model is perhaps a happy compromise between  an out-and-out capitalist model whereby market forces dictate development (meaning individual firms are primarily reactionary and fighting against one another), and a central government owned model which as history has shown, tends to restrict enterprise and dynamism. Reaching a happy balance between both models above is crucial to the success of a sector that relies upon several brilliant individual firms working together for the greater good of the wider industry. The space industry today is thriving and growing across the world perhaps at a faster rate than it ever has. Could the energy supply industry benefit from utilising a similar model? I certainly think so.