Hydrogen powered sky taxi boasts record breaking 400km range

Hydrogen is still lagging behind electric batteries as an energy source for tomorrow’s fleets of “green” electric vehicles, in a replay of the great Betamax versus VHS video wars of the 1970's, but in the past couple of months we’ve seen the emergence of the first commercial hydrogen powered semi-trucks in California, and now the first fully electric Vertical Take Off and Landing (VTOL) flying sky taxi from Alaka’i Technologies.

Unlike other companies in the sky taxi space though, like EHang and Volocopter, who flew their first test flights in Dubai in 2017, and who rely on traditional Lithium Ion batteries, Alaka’i have neatly side stepped the battery energy density problem that’s plaguing companies using LiOn batteries by using hydrogen fuel cells to power their five seater Skai sky taxi, and the result is a massive category killing 400 mile (640km) range. Putting that into context that’s a long enough range to help sky taxis break out of their box of just being inner city vehicles, like the ones Uber are planning, ferrying people from one place in a city to another, to finally realising much longer range travel. And that could be a game changer.

Images courtesy: Alaka'i Technologies

Hydrogen is a difficult fuel to deal within an automotive context, but it might just be the shot in the arm that the electric aviation and electric aircraft industry needs to get VTOL multi-copter air taxis up and running.

Current lithium battery technology offers relatively lousy energy density when compared to hydrogen fuel cells, that severely limits the range figures of the current E-VTOL projects from companies like Airbus and friends. But hydrogen offers up to 10 times the energy density, as well as very fast re-fuelling - if you can deal with the inefficiencies of producing, transporting and storing it that is. And those difficulties can be better managed in a centralised aviation model that doesn't need to roll out across the entire road network.

And those are the reasons why US based Alaka'i has spent the last four years busily beavering away at building Skai. According to an interview with SoCalTech, the company is operating under the funding of a sole investor, who has carried it through design, development, prototyping and is now footing the bill for final FAA certification, which Alaka'i CEO Steve Hanvey says he believes should be possible before the end of 2020 due to the simplicity of the airframe.

As you can see Skai looks simple - it's a six rotor multi-copter with large carbon props that were co-designed by BMW’s Designworks business unit. There's no coaxial props, ducted fans, tilting elements, wings or pusher props – the Skai will operate much like a drone, requiring thrust at all times to stay in the air, suggesting that future models that do have some wing lift capability in forward flight will have even more impressive range figures.

It seats five, including a pilot – and indeed will be piloted rather than autonomous upon launch, but Alaka'i says it's certainly looking to make these things pilotless in the future.

In terms of safety, the Skai has some redundancy built in with its six props and can probably fly if a couple of those go down. And in the case of total failure, it carries an "Airframe Parachute" to bring it back down to Earth gently. Of course, even the fastest ballistic parachutes take some time to open out and slow down a fall, meaning that they're basically useless below a certain altitude – and I'll be interested to discover how Alaka'i is dealing with the so called "Death Zone" below that.

The company says it's planning and designing "all touchpoints, digital, physical and service" for the air taxi concept, so it seems it's keen on owning the whole operation as opposed to plugging in to a service like Uber Elevate.

The prototype looks impressive, the powertrain seems to have a genuine opportunity to beat the battery guys into the air, and a 4 hour 400 mile range will make this thing immediately useful, and potentially profitable, as soon as it's certified and ready to go.

Sky taxi’s just got the kick they needed to push them into the prime time spotlight so it’ll be interesting to watch this develop.

Source: Alaka'i Skai