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Ever since we started to see companies touting "flying taxis" in the form of autonomous eVTOL flying craft, I've been issuing warnings.
Right now billions of dollars in seed and venture capital is being poured into companies that claim they will revolutionise urban air transport through the development and deployment of these electric-powered vertical take-off/landing craft.
Unfortunately, as per my warnings, many people will lose their shirts through this folly and today I'll explain why, as well as pointing to some that are already in the process of crashing and burning.
On the face of it, a low-cost passenger aircraft that can negotiate an urban landscape without the need for a pilot and without the need for expensive fossil fuel sounds great.
Instead of trying to fight your way through the clogged streets and motorways of a large urban centre you could (in theory) simply step onboard one of these flying taxis, enter your desired destination and be whisked into the skies, travelling "as the crow flies" without delay or hassle. A journey that might take up to an hour or longer in a car could be completed in five or six minutes by flying taxi.
Sounds like a winner of an idea and something that could make the creators and operators of these crafts a pretty sizeable sum of money, right?
Well a significant number of companies have been set up on the premise that they can make this dream a reality and investment capital has flowed like water.
Unfortunately, as things stand right now in terms of technology, it is utterly impossible to deliver this dream in any way that is even remotely viable from a profit perspective.
This leaves me wondering how those in charge of these investment companies and VC funds manage to have control over such huge sums of money because, to be blunt, they are idiots.
Has the concept of due dilligence been removed from the investor landscape or something?
The problem is that, given the current state of battery technology, there is just no way these craft can be built in a way that allows them to provide a profit for their operators.
Sure, we can build electric cars that will travel hundreds of Km on a single charge and have batteries that last ten years or more but the demands of flight are a completely different thing.
For a start, in an EV, weight is a far lesser concern than in a craft that will fly. An EV may carry hundreds of Kg of batteries but, thanks to stuff like regenerative braking, that doesn't impact performance or efficiency nearly as much as it would in a flying craft.
Another consideration is that the battery in your average EV is very lightly stressed. The ability of a battery to deliver power is referred to as its 'C' (capacity) rating. If you have a 10KW battery and you discharge it in an hour, that's a C rating of one. If you discharge it in 30 minutes then the C become two, etc, etc.
With most EVs delivering several hours of energy per charge (ie: with a 300Km range, a vehicle travelling at 100KPH will last 3 hours) then the battery only has to deliver its power at around 0.3C most of the time. A very light load.
Compare this to a flying craft. At best, that craft will have a maximum flight time of around 20 minutes per charge meaning that the battery is being drained in a third of an hour producing 3C of discharge -- that's an order of magnitude higher than an EV.
The higher the discharge rate of a battery, the shorter its life. Every battery has an internal resistance and that resistance means that some of the power is converted to heat within the battery. Given that the formula for the energy wasted is I^2R (current squared times the resistance) it's easy to see that increasing the current by a factor of ten actually increases the energy wasted as heat by a factor of 100.
In short, the actual useful life (before it needs to be replaced rather than recharged) of a battery used in a flying taxi will be far, far less than that of an EV. Ten years in an EV may equate to just a few months or even weeks in a heavily used flying taxi.
There's also another factor that will hugely impact the service life of a flying taxi's battery -- the charge/discharge levels.
Most EV manufacturers recommend not fully charging the battery to 100 percent on a regular basis and also recommend against discharging below 20 percent or so. By staying in this range the livespan of a lithium-ion battery is significantly increased. Likewise, avoiding "fast charging" is also recommended where possible so as to produce maximum battery service life.
This is easy enough with an EV but almost impossible with a flying craft.
Any battery capacity that is not actually used in a flying craft represents nothing more than dead weight that has to be carried around. Likewise, any uncharged capacity is also dead weight that reduces flight-times and payload capacity -- both of which are crucial factors in the profit equation.
In simple terms, present battery technology simply isn't up to the task of powering these flying taxis. They will wear out within a few hundred cycles because they'll be heavily stressed through 10C discharges as well as by fast-charging and repeatedly operated outside the 20 to 90 percent charge range.
If a battery for one of these flying taxis costs (say) $100,000, which is not unreasonable when you consider this is "aviation" and all things "aviation" have a huge premium attached to them then if we accept that 200 charge/discharge cycles are proabably the limit of safe operation -- the price per flight now becomes $500 in battery replacement costs alone.
This $500 per flight figure comes before you have to add on the cost of charging the battery, the capital cost of the craft itself, infrastructure such as charging equipment, air traffic management and a myriad of other overheads. The reality is that any company operating one of these craft will have to charge around $1,200 to $1,500 per flight and even if there are four passengers onboard, that's $300+ per seat.
Now, to be fair, there may be some who'll gladly pay that much to save an hour in traffic but are there enough *actual* customers that the billions currently being poured into these air taxi companies can ever be recovered?
I really doubt this is the case -- otherwise we'd see the skies over our cities filled with helicopters, wouldn't we? The reality is that if the demand was there, it would already be filled by helicopters but although such services do exist, they're not exactly plentiful and, in reality, they could still undercut the prices that these eVTOL taxis would have to charge.
With all this in mind I was not suprised to hear this week that two of the largest eVTOL startups are rumoured to be on the verge of collapse, despite the huge sums that have been poured into them by idiotic investors who clearly didn't even bother to hire someone with knowledge of the technology to advise them.
The future of Lilium is in doubt after the the German government declined to step in with funds to avert insolvency.
At the same time, Volocopter narrowly avoided going down the gurgler earlier this year and also faces a financial crunch after failing to deliver on the promises it's been making.
Just like the ill-fated Martin Jetpack, these craft are utterly nonsensical "pie in the sky" concepts at this point in time. Until we have an entirely new generation of battery technology they will never be commercially viable and that new battery tech is, in my considered opinion, at least 10 to 15 years away.
As for me... I'm investing in the designer apparel marketplace because I can see a huge number of idiot financiers losing their shirts in the electric air-taxi market so they'll be needing replacements.
Again, I wonder how so many very stupid people manage to find themselves in control of such a huge amount of investment capital. It strikes me that these people can't have obtained all that money by fair means - given their inability to perform even the most basic research into that which they are investing.
Carpe Diem folks!
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