Skai made massive waves last month with the launch of its long-range hydrogen-powered eVTOL air taxi prototype. In an interview with New Atlas, Skai’s CTO tells us these flying commuter automobiles will value about the identical per mile as an Uber journey, and that he expects to be able to land them nearly anyplace.
Brian Morrison, CTO of Skai and its father or mother firm, Alaka’i Applied sciences, is just not shy about what his company is proposing: a democratization of air transport that doesn’t have to wait for a huge leap in lithium battery know-how. Battery power density is among the two largest challenges dealing with eVTOL builders at this stage, the other being FAA certification.
Morrison says his firm’s use of liquid hydrogen gasoline utterly leap-frogs the difficulty of find out how to get electric air taxis flying for more than 20 minutes, and that Skai is working “hand in hand” with the FAA to finish the certification process for this utterly new sort of aircraft – a course of he believes will probably be completed and permit for business flights by the top of 2020.
That is an audacious plan, but when it comes collectively, it’d put Skai properly forward of the remainder of the pack in bringing reasonably priced vertical commuting to the plenty. We spoke with Morrison over Skype this morning. What follows is an edited transcript.
Loz: The first thing everyone needs to know is: have you received it flying yet?
The check car is up at Minuteman Subject up in Stow, and all of the exams we’ve been conducting thus far have been with it tethered to a concrete pad, which is a part of the FAA necessities.
If not tomorrow, then Monday we’ll be able to take the tethers off, however we will’t until the FAA comes out to do another website inspection to be sure that they’re proud of all the documentation. As soon as that occurs, we’ll take the tethers off and be capable of raise off.
Loz: What is going to the flight testing program appear to be for you guys?
Until this level, it’s been rotor run-ups to a sure energy degree, growing energy to full power. Operating by way of the regime that the motors function in. We’ve run individual motors before, that is the primary time we’ve had all six on a single construction, operating off hydrogen gasoline cells. We’re making sure we consider it every step of the best way before we take the tethers off.
Coping with the hydrogen
Loz: how are you storing the hydrogen?
We use liquid hydrogen on board. The gasoline cells truly use it in gaseous type, so it’s stored in liquid nevertheless it comes out and goes by way of an enlargement chamber which permits it to vary from the liquid state into a gaseous state. Then we put it by way of a heat exchanger to heat it up a bit bit, and that’s what goes into the gasoline cells.
Loz: What measurement tank are you operating in there?
We have now tanks ranging from 110 liters all the best way up to 400 liters. The 400-liter tank is the one which’ll give us, in round numbers, 4 hours of flight time and 420, 430 miles (676, 692 km) of range.
Loz: There have been lots of people making manned multicopter designs, but not lots of gasoline cells. What made you guys determine to go down this path?
Once I began this exercise again in 2012, I too was looking for a method to do it with lithium-ion batteries. I’m a techniques engineer by coaching, and I spent actually months operating totally different simulations. Wanting on the raise offered, taking a look at how long we might stay within the air, how long you might hover, versus how much power you need.
I decided that from an air taxi standpoint, 15 or 20 minutes flight was never going to be enough. Because it’s a must to have emergency reserves as nicely. For those who only have the power to stay in the air for 20 minutes, the FAA would solely allow you to fly 10 minute routes so you’d have some reserve left over. That didn’t appear practical, so I began casting about for a greater answer, and began taking a look at hydrogen gasoline cells for that. We’ve been working with that ever since.
Loz: I’ve been writing about gasoline cells within the auto business for a very long time, and it’s all the time seemed to me like a know-how that was never going to take off, just due to the problem round storing the stuff, and integrating it into the gasoline station provide chain. All of it appeared too troublesome. However I assume within the aviation world you don’t want hydrogen stations on each third nook?
You really don’t. And by the best way, increasingly more corner gasoline stations – notably in California, now Connecticut and Massachusetts – are beginning to have gaseous hydrogen dishing out capability.
I spent yesterday with a serious hydrogen supplier, speaking about having them supply not simply gaseous hydrogen but in addition liquid hydrogen at these stations – that might remedy the supply of provide drawback fairly easily for us.
They have already got liquid hydrogen on website, because it’s most effective for them to retailer it in bulk type in liquid, then convert it to fuel and pressurize it earlier than they put it in anyone’s automotive. This manner we’d be capable of siphon off a number of the liquid and use it to gasoline our automobiles immediately.
Loz: You wouldn’t function out of depots using your personal supply?
Nicely, there’s numerous alternatives. One is you reap the benefits of what’s already commercially obtainable. Another is, maybe in elements of the state where you don’t have plenty of that, you might have your personal electrolysis and liquefaction capability.
Or you just have your personal tanker truck. We’ve our own tanker truck right now. It solely carries about 3,500 liters of liquid hydrogen, but that’ll gasoline the car quite a few occasions. So you can literally have the plane meet a movable car someplace in a parking zone, just land subsequent to it when it’s essential to refuel, after which take off again. That provides us a nice cellular refueling capability.
On the Skai plane’s design and safety issues
Loz: Altering tack slightly, it’s a six-rotor design. You’ve acquired some redundancy there. You chose to not go together with coaxial props, ducted fans, or any sort of tilt-wing design that’d offer you wing carry for additional effectivity in the air. What was the considering there?
All true! The core philosophy is hold it simple. And by protecting it simple, we’ll get certified sooner and we’ll be a a lot decrease value car than the extra complicated designs. You add complexity, you add weight, and also you add certification danger.
Loz: So these multi-mode VTOL takeoff jiggers that change forward into winged flight with pusher props or no matter, you are feeling that’d be an extended path to certification?
I do, yeah.
Loz: One factor that fascinates me is the worst case safety factor, whereby everybody’s acquired ballistic ‘chutes on this stuff, however they only don’t work beneath a sure altitude. I’m actually interested to hear how you’re coping with that drawback.
We’re working very intently with the ballistic parachute manufacturer to engineer it as a system moderately than just tacking on a parachute.
Part of that system is the flexion you’ll get out of the landing skids. A part of the system is the flexion you get out of the seat itself. So you possibly can shield the occupants as much as a reasonably vital G impression just via a mixture of the skids and the deflection of the seat. And the car itself can deform or crush to absorb a few of the power.
Our expectation is for that to soak up sufficient power that above a certain altitude, you’ll have time to deploy the parachute and descend safely from the parachute. But you’re proper, there are considerations that everyone’ll be dealing with about how to try this.
On Skai’s own air taxi service, and what it’ll value
Loz: Now, it appears you guys have designs on operating the air taxi service fairly than just making the automobiles and plugging into one thing like Uber Elevate, is that this right?
That’s right. Partially because three of our rules have all operated air taxi providers prior to now. So we know a bit about establishing and operating an air taxi service. We’ve already acquired an app up and operating that allows you to guide a flight.
We’ll happily sell to others if they need to purchase some to make use of in their air taxi service – indeed we’ve already had enquiries from some. However we additionally plan to be working our personal, yeah.
Loz: What’s the advantage of this stuff over helicopters, are they going to be that less expensive?
Properly, say a standard helicopter – until you’re talking a few Robinson – but a standard turbine helicopter is 4, six, seven, eight million dollars relying on the way it’s outfitted. You’ve obtained an engine operating at 6,000 rpm, and it’s a must to use a posh transmission to get it right down to sometimes 300 rpm on the rotor blade.
Those transmissions are heavy, they usually fail. One of the sensors you’re required to have on board known as a chip detector, so you possibly can detect when the gears within the transmission are beginning to come aside.
Right here what we’re doing with electric motors, they’re all direct drive, so there’s no transmission involved. They use digital velocity control, digital computation to regulate the velocity and course of the motors, so it focuses on simplicity and security and making the car as mild and protected as we will.
The opposite massive benefit you get with six rotors unfold out from the center of the car is you possibly can even have a parachute on board.
Loz: Proper, it will possibly hearth straight upwards. So when it comes to journey value, obviously the typical on a regular basis Joe isn’t getting round in helicopters as part of their transport mix lately. What sort of value discount are your numbers displaying at this level?
With out going into plenty of specifics, more than a ten-fold reduction.
Loz: OK, and have you accomplished any modeling on how lengthy a flight would have to be earlier than it turns into cheaper than driving a automotive, or something like that?
Properly, the worth proper out of the box shall be similar to what a generic Uber would cost to go the same distance. The distinction, in fact, is that you simply’d get there much quicker within the sky than you’d on the roads.
Loz: Actually? Similar to the cost of a land based mostly Uber?
Loz: Holy moly. That modifications all the things.
Yeah. And to reply your query, we’ve carried out a variety of modeling on that, a variety of analysis using not solely our own instruments, but some business main tools to guage how totally different modes of transportation work, and are picked up by the traveling inhabitants.
Loz: The place does that large value reduction come from? Is it the price of the car? The gasoline? Pilots? What’s driving it?
All of those issues. Hydrogen proper now’s on a par with gasoline, nevertheless it’ll turn out to be cheaper over time. The pilot, we’re certifying the car initially with a pilot on board, but in a short time we’ll be capable of function the car over a tactical datalink from the bottom, so we gained’t have to hold the load of the pilot around. So that you get more passengers or payload functionality with a pilot still in full command of the car.
Obviously long run you’d get to an autonomous version, the place you don’t need a pilot concerned at all.
Loz: So your intermediate step is principally a knowledge middle full of youngsters enjoying video games, successfully?
Absolutely! I feel they’ll should be 21, but you get the thought. The other huge factor … properly, we’ve all been concerned in air taxis earlier than, so let me offer you an instance. If in case you have a hard and fast wing Cirrus aircraft, that’s a piston engine making 330-350 hp. Each 2,000 hours you need to do an entire teardown and overhaul of the engine, and it costs US$60,000.
That working value needs to be factored into your value per seat mile that you simply’ll supply to the general public. That’s every 2,000 hours with a piston engine.
Alongside come gasoline cells, the place you don’t need to do anything until 20,000 hours, and all you must do is swap out the stack. All the remainder of the gasoline cell stays in place. That’s an enormous discount when it comes to OpEx.
Interview: Skai claims its air taxis will value the same per mile as taking an Uber [New Atlas]