Aircraft

Skai hydrogen-powered eVTOL air taxi boasts enormous 400-mile range

Alaka'i Technologies' Skai prototype is already in the process of FAA certification
Alaka'i Technologies' Skai prototype is already in the process of FAA certification
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Alaka'i Technologies' Skai  uses single large carbon props
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Alaka'i Technologies' Skai  uses single large carbon props
Alaka'i Technologies' Skai  is a simple five-seat air taxi
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Alaka'i Technologies' Skai  is a simple five-seat air taxi
Alaka'i Technologies' Skai  can accommodate one pilot and four passengers, with a carrying capacity of 1,000 lb (454 kg)
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Alaka'i Technologies' Skai  can accommodate one pilot and four passengers, with a carrying capacity of 1,000 lb (454 kg)
Alaka'i Technologies' Skai prototype looks terrific
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Alaka'i Technologies' Skai prototype looks terrific
Alaka'i Technologies' Skai prototype is already in the process of FAA certification
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Alaka'i Technologies' Skai prototype is already in the process of FAA certification
There are no tilt rotors, wings, or coaxial props – this is pure simplicity
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There are no tilt rotors, wings, or coaxial props – this is pure simplicity
A hydrogen fuel cell powertrain allows 10 times the storage capacity of lithium batteries giving Skai a 4-hr/400-mile range between refueling
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A hydrogen fuel cell powertrain allows 10 times the storage capacity of lithium batteries giving Skai a 4-hr/400-mile range between refueling
The company is hoping t have FAA certification by the end of 2020
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The company is hoping t have FAA certification by the end of 2020

A new electric vertical take-off and landing (VTOL) air taxi company came out of stealth mode today, using a hydrogen fuel cell powertrain that neatly sidesteps the energy density issue that's holding back battery-powered aircraft. Alaka'i Technologies' Skai machine has a range of up to four hours/400 mi (640 km) and a five-passenger capacity.

Hydrogen is a difficult fuel to deal with in an automotive context, but it might just be the shot in the arm that the electric aviation industry needs to get VTOL multicopter air taxis up and running. Current lithium battery technology offers poor energy density, which severely limits the range figures of current e-VTOL projects. But hydrogen offers up to 10 times the energy density, as well as gasoline-quick refueling, if you can deal with the inefficiencies of producing, transporting and storing it. And those difficulties can be better managed in a centralized aviation model that doesn't need to roll out across the entire road network.

Thus, Massachusetts-based Alaka'i Technologies has spent the last four years beavering away at building a hydrogen-powered air taxi, which it launched today in California. 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 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.

The company is hoping t have FAA certification by the end of 2020
The company is hoping t have FAA certification by the end of 2020

The aircraft itself does look simple; it's a six-rotor multicopter with largish carbon props, co-designed by Designworks (the design innovation studio for BMW). 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.

Alaka'i Technologies' Skai  can accommodate one pilot and four passengers, with a carrying capacity of 1,000 lb (454 kg)
Alaka'i Technologies' Skai  can accommodate one pilot and four passengers, with a carrying capacity of 1,000 lb (454 kg)

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. In the case of total failure, it carries an "Airframe Parachute" (capitalization theirs) to bring it down softly. 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 we'll be interested to discover how Alaka'i is dealing with the "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 (purely theoretical) service like Uber Elevate.

There are no tilt rotors, wings, or coaxial props – this is pure simplicity
There are no tilt rotors, wings, or coaxial props – this is pure simplicity

The prototype looks impressive, the powertrain seems to have a genuine opportunity to beat the battery guys into the air, and a 4-hr/400-mile range will make this thing immediately useful, and potentially profitable, as soon as it's certified and ready to go. We'll be keeping our eyes on the Skai.

See a video below for a closer look at Alaka'i Technologies' eVTOL vehicle.

Source: Alaka'i Skai

Alaka'i Skai - Hydrogen powered VTOL air taxi

20 comments
Howe
Impressive, its about time hydrogen fuel cells take flight. Batteries are better for cars, but unless they have a big breakthrough, hydrogen will likely hold the energy density lead for another 15-20 years.
CAVUMark
"turns the every day commute into a fascinating experience"... shissh, the marketing people are working overtime. Nice looking product though.
erl
I hope they build in an airplane parachute called CAPS :)
Vanilla Cat
The FAA will NEVER permit these flying Ginsu Knives to crowd the skies above populated areas.
pATREUS
There is far more air space available than tarmac roads. Solutions like these (with reliable traffic control) will eradicate travel congestion.
Knut
The hydrogen tanks are heavy - but why not use more Norwegian technology: the Wankel engine works fine with hydrogen and is smaller than the fuel cells and much lighter. "burning" is when hydrogen binds with oxygen and produce clean water. The efficiency of the motor is just slightly less than fuel cells, but place funding on the table, prototypes have this with much better efficiency. Look at the chemical structure of the hydrogen atoms and you will see that nothing can beat it - ever. A VTOL would be more convincing and should give a better distance. They fitted the Wankel on a boat, and a tiny engine pushed the boat close to flying. So what about a plane - should be a better mix.
David Evans
Vanilla Cat, what do you think happens to a helicopter when it loses its tail rotor over a populated area?
Brian M
Nice to see Hydrogen taking off (pun intended!). Its a technology that has unfortunately been eclipsed by battery technology that replaces one problem (CO2) with others such as how to supply enough battery storage and how to recycle used batteries. Hydrogen is a great alternative if the supply issue can be dealt with.
grtblu
As Boeing's Max 8 troubles show, single points of failure in aircraft are unacceptable. This aircraft has 4 propellers, if one drive fails, can the thing be controlled? The configuration means that a pilot doesn't actually fly the machine a computer does. These things fly like a powered brick with a glide path of zero. So what redundancy exists in the computer controls to deal with software and hardware failures? These are great concepts, have interesting futures, but need real engineering including detailed FMEA's (that's Failure Modes and Effects Analysis) to make them safe. That being said, it looks fantastic.
guzmanchinky
So many companies developing these machines, I hope they become reality soon. It would be nice to own a "helicopter" that doesn't require the training and counter intuitive lightning fast reflexes to fly one, and which can accommodate a ballistic parachute.
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