Aircraft

The Watfly Atlas eVTOL: What, that flies?

The Watfly Atlas eVTOL: What, ...
Tailsitter design makes it easy for the Atlas to transition to efficient winged flight
Tailsitter design makes it easy for the Atlas to transition to efficient winged flight
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A tail-sitting eVTOL with a gimballed cabin
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A tail-sitting eVTOL with a gimballed cabin
Four large ducted fans, designed to keep things relatively quiet
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Four large ducted fans, designed to keep things relatively quiet
Everything's carbon, naturally, to keep weight down
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Everything's carbon, naturally, to keep weight down
Tailsitter design makes it easy for the Atlas to transition to efficient winged flight
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Tailsitter design makes it easy for the Atlas to transition to efficient winged flight
Watfly hopes to have these on sale in 2021, certified as Ultralights, for around US$150,000
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Watfly hopes to have these on sale in 2021, certified as Ultralights, for around US$150,000
Once in forward motion, the Atlas is a big wing with a cabin in the middle
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Once in forward motion, the Atlas is a big wing with a cabin in the middle
It seems the team plans to build a two-rotor version with a fixed cabin as well
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It seems the team plans to build a two-rotor version with a fixed cabin as well
Without a tilting cabin, pilots would get a great view of the Earth below, but very limited forward visibility
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Without a tilting cabin, pilots would get a great view of the Earth below, but very limited forward visibility
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Of all the many eVTOL personal flight machines we've seen lately, this one's caused the most discussion in the now-virtual New Atlas office. The work of a young Canadian company, the Atlas is a 4-rotor manned multicopter design, in which all four of its ducted rotors are inline along a single wing.

My first thought upon seeing it was "why?" Every other design places props on at least four corners, indeed sometimes even more spread out in designs like the Volocopter. That ensures it's easy to maintain stability in a hover against shifting winds, with the instant torque of the electric motors driving the props able to respond and re-balance the aircraft in fractions of a second.

On second look, though, the Watfly design might have more to it than meets the eye. It's based upon a less common drone design – the tailsitter – which could confer its own advantages. Tailsitters give you the efficiency advantages of winged flight - and some of the same control surfaces – without a lot of the complexities of many tilt-rotor designs. The whole aircraft tilts once you're up to speed, and you fly on the wing for the majority of your journey.

Once in forward motion, the Atlas is a big wing with a cabin in the middle
Once in forward motion, the Atlas is a big wing with a cabin in the middle

On the other hand, most tailsitters don't have people in them, and most people probably don't want to spend the majority of their flight pitched over on their stomachs looking straight down. So the Atlas aircraft unfixes the single-seat cabin from the wing, allowing it to rotate independently such that it can stay upright whether the wing's pointed upwards, horizontally or anywhere in between.

And there could be some advantages to that. In terms of comfort, the pitch of the cabin can stay relatively stable even if the wind's blowing the wing around a bit. Mind you, you'll still feel the roll and yaw motions, which could be significant in a hover. Indeed, perhaps in the future, the cabin can be fully gimballed to stay level on all axes.

In a short interview with Robb Report, co-founder Gonzalo Epinoza Graham laid out his expectations for the Atlas: a 285 lb (129 kg) weight thanks to carbon fiber construction, 8.2 feet (2.5 m) high with a 15-foot (4.6 m) wingspan. It'll carry a maximum of 250 lb (113 kg) at a maximum speed around 125 mph (200 km/h). Batteries "about a quarter the size of a Tesla's" will charge up in two hours, and offer 15 minutes of hovering or around an hour of flight on the wing.

Without a tilting cabin, pilots would get a great view of the Earth below, but very limited forward visibility
Without a tilting cabin, pilots would get a great view of the Earth below, but very limited forward visibility

Graham believes he'll have the Atlas on sale as soon as next year for around US$150,000, certified as an Ultralight by the FAA. As such, you'll be restricted as to where you can fly the thing (certainly not over urban areas) but you won't need a pilot's license. It'll have some sort of collision avoidance software, as well as some sort of parachute system, although as with nearly all current eVTOL designs, you can still kiss your butt goodbye if the Atlas fails below the minimum height from which the parachute can save it.

The Ontario-based team has built and flown a number of decent-sized unmanned tailsitter prototypes, but is yet to get a version built with the rotating cabin on board. Extremely weird at first glance, this thing may have its merits and we'll keep an eye on the Watfly team to see how things develop.

Source: Watfly via Robb Report

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13 comments
Towerman
Interesting, something different but not in an over the top way, this could fill a potential niche in the general multicopter field. (a quick get away from the concrete city life) out to the open outskirts for a weekend camp. And then back in a whizz when the weekend expires.

I love the idea of a gimbaled Cabin as Loz pointed out (so would be great if this come to fruition), but first let us see some trial flights, and i like the shape and looks of the Cabin on this Atlas. Keep it up i expect to see good progress !

BTW Loz, could you try to perhaps contact the guys at Skai for a follow up review, i would really like to get some fresh updates on that machine also. It's been a very long time.

guzmanchinky
Cool new design, I like how it easily transitions to winged flight, unlike a quadcopter.
paul314
So if there's recharging at the other end, that's 200km of range. Of course with one person plus minimal luggage the applications are restricted somewhat.
Thud
Something doesn't add up. How does it weigh 285lbs and carry a battery 1/4 the size of a Tesla battery? Model S batteries weigh almost a ton.
Thud
Sorry they weigh about 1,000lbs. Still doesn't add up.
Howie
One way to make ballistic parachutes safe is for the FAA to mandate that landings and take offs must have an attendant 300 foot precipitous drop. This means only tall building roof tops or a cliff edge landing zone. An approach would then transition from a safe 300 feet to
an immediate survivable 10 feet or so, if the craft lost control or power either on approach or right at the pad. This limitation for landing pads would then mean there is no death zone.
Towerman
@ Howie
Indeed, Indeed. In addition to your suggestion, there are more options ! If certifying is the only thing holding it back, make take off's over water and approaches to landing over water mandatory. Both your option and this one would be enough for the regulations to approve of these machines, i really really cannot see why not ???!
Now that there's no more excuses, let's get them up in the air already !
Tris
@Howie, With a dead engine the need to keep wings lifting with minimum lift speed into a horizontal landing is far better without all the drag from stalled fan props that steepen a decent angle or increase impact speed. Ballistics are a bad option as inefficient weight carried with no value at the dominant sort altitudes. You’ll see in the SkyDrive eVTOL thread what is far better using Electric Propulsion without dangerous parts.
@Thud, You are so right that things don't add up. They specify a 2 hour recharge. At 220 volts and 50 amps, a typical stove outlet, it could supply 22kWh of energy in two hours. Tesla batteries store about 250 Wh/kg so the battery would weigh 88 kg or 196 pounds. Obviously battery weight is not included in the figures given.

@Towerman, The Watfly is an interesting design but as we discussed earlier in the comments on the SkyDrive from the pictures it looks like it is an efficient body part eliminator in that judging from the height of the man in the pod it looks like he is taller than the top of the engines on the ground. Also, who has $150,000 for this toy for the rich?
Tris
@guzmanchinky, Looks can be deceiving. A major problem with tail-sitters is controllability at zero airspeed and it looks like the Atlas may suffer the same problem due to the lack of four corner vertical thrusters. In analyzing the forces on the vehicle imagine the vehicle pitched slightly from vertical. The thrust vector of the engines will be through the center of gravity thus the engines produce no torque on the aircraft and can't right the vehicle. From the pictures, is pitch controlled by moving the entire wing or are there control surfaces at the trailing edge of the wing that will have the ability to rotate the vehicle. Maximum force will be when the controls are at 45 degrees and it is unlikely that you can move the control surfaces to 45 degrees in under a second. This time delay is what limits the range over which the vehicle can right itself. Stabilizing in a micro second vs a fraction will remove the Atlas eVTOL advantage of a smooth flight as AIP would be by far much better.
Towerman
I take into account what you say Tris, it's a good analysis. However i say the concept looks good as a starting point.
Let them build a prototype, test, update and tweak it from there, it's not to say the end product will look exactly like the starting product.
They simply need to take the limitations seriously, (which i believe they will, either via testing a prototype) Or brainstorming the attributes that would make it not work. Looking at data or past experiences of others etc...

Once they figured it out, changed variables, gone through a few prototypes, tested it extensively, the product can be tweaked to perfection.