Aircraft

Ballistic multi-parachute system saves eVTOL in low-altitude fall

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The X2 eVTOL aircraft fires its low-altitude ballistic parachute
AeroHT
The X2 eVTOL aircraft fires its low-altitude ballistic parachute
AeroHT
The X2 aircraft fires its ballistic multi-parachute safety system at just 50 m off the ground
AeroHT
Despite hitting the ground at 5.2 m/sec, the company claims the aircraft is "unharmed"
AeroHT
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What happens when something goes very wrong in an eVTOL aircraft? China's AeroHT has released video of its innovative low-altitude multi-parachute system turning a catastrophic propulsion system failure into a soft-ish landing from just 50 m (164 ft) up.

For many years, eVTOL aircraft manufacturers have been talking about using ballistic parachutes as a last-resort safety measure, and we've been wondering just how practical that kind of thing could possibly be from altitudes below about 100 m (328 ft), where such systems will have precious little time to deploy.

AeroHT has now answered that question, by releasing a video of its own multi-parachute safety system deploying from an X2 manned multicopter prototype at just 50 m off the ground. The chutes start grabbing air within about a second and a half of blasting out of the front of the aircraft, they're fully deployed by about a second and a half later, and they manage to catch the X2 before it flips over, and hold its descent to 5.2 m/sec (18.7 km/h, 11.6 mph) before it hits the ground.

You'll notice AeroHT has conveniently cut this video to remove what's presumably a fairly violent swing as the prop brings the aircraft's nose back up to level, as well as the moment when it smacks down onto the ground. The company says the aircraft wasn't damaged, and while it does very much seem like a survivable fall for any passengers on board, it sure won't be comfortable – that landing speed is equivalent to landing a 1.4-m (4.6-ft) high jump, with no visible suspension to soak up the spinal punch.

Still, according to Omni's Free Fall Calculator, an object dropped from 50 m up would ordinarily hit the ground 3.2 seconds later, at a speed around 31.3 m/sec (113 km/h, 70 mph). So while a catastrophic failure and parachute landing doesn't look like a lot of fun, I sure know which speed I'd rather hit the ground at.

We wish we could see an uncut version of this video; edits like this inherently make people suspicious of a company's claims. But it looks plausible enough to us, and we can imagine a company like this not particularly wanting potential buyers to see the cabin getting swung around in the air, or banging down on the ground. So we're willing to give AeroHT the benefit of the doubt on this one.

Despite hitting the ground at 5.2 m/sec, the company claims the aircraft is "unharmed"
AeroHT

During the same presentation, at parent company Xpeng's Tech Day 2023, AeroHT also showed off a six-wheel-drive "aircraft carrier" van, as well as the latest version of its flying supercar.

Source: AeroHT

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18 comments
El Greco
Your comments are spot on and it's good to see m/s translated into something meaningful. Uncomfortable but preferable and plausible.
David F
Presumably the use of a parachute means the rotors are inadequate for auto-rotation decent. Have any eVTOL craft been tested for auto-rotation decent in the event of power failure.
John Nelson
Aircraft of this type glide only slightly better than a grand piano when even one of their powerplants/rotors fail. This has been a trait of the type all the way back (at least) to the Moller "Sky Car". Auto rotation relies on aero drag to keep the rotor turning during unpowered descent, and on that rotating mass to provide enough inertia to arrest descent for landing. I would not leave a two-foot over in an aircraft like this without a proven BRS on board.
freddotu
Autorotation also requires a pitch change on the lift-producing blades. UAS type lift systems are managed by changing RPM, which no longer factors in the calculations when RPM is zero. Is the deployment system automated, or will there be the human delay involved, further increasing the plummeting speed and impact forces?
Golfer299
The article seems a little overly critical for something that works but isn't perfect - and something that never could be perfect.
sidmehta
If multiple parachutes can work to halt the fall on a simple craft like this, why not on a commercial jet? I realize there would be some engineering challenges but smart people can come up with breakthroughs. Maybe the engineering problems could be crowd-sourced and solved.
Global
Exploding parachutes up and around rotating blades is grasping for dear life with hopes they will not be damaged, and grab enough air before hitting the ground. Has anyone looked a lower body two stage, impact absorbing air bag type system that buffers the final impact, but also possibly creates a larger air mass area to control/guide descent trajectory, & rate?
Dcisfun
Just needs a NASA type airbag for the car to inflate before it hits the ground to avoid the spinal injury from using parachutes alone. It worked for NASA when landing in Mars!
DrDlDoe
More bull from the far corners of shyster land - um 5.2m/sec (their figure)?. Multiply by 3.3 and it's 17.16 feet/sec. Multiply by 60 and it's 1,029 feet per minute! Multiply by 60 again and it ends up at 61.78 Miles per hour!! "Undamaged"? Myass. Crushed like a tin can rather. With probably fatal spinal injuries. What a deal!
dave be
@DrDlDoe don't quit your day job there chief. Thats 11.69 mph not 60. You just divided by 1000 instead of 5280 to get your mph figure.