EHang-The Ghost Drone

EHANG,184

EHang, the maker of the Ghost Drone just launched something at CES 2016 which might get a lot of folks excited. It’s basically a manned version of a traditional multicopter UAV called EHang 184 that provides means of personal transportation for a single passenger weighing not more than 100 kilograms or 220 pounds. So first of all it’s not going to be the choice of NFL linemen because this maximum payload is for the passenger and personal belongings (luggage) combined. So a reasonable sized person would not be able to fly it having boots on . "The 184 was named for ‘one’ passenger, ‘eight’ propellers, and ‘four’ arms". It’s a bit less ingenious than expected, I would personally like a less dull name for something that tends to be cool, for example the EHang Storm (copyright).

Other attempts to create a manned version of “drones” range from the Hoverbike which is at least a cool concept to the Flike which is a bit hard to take seriously, looks extremely dangerous to fly. None of these guys made it to the market just yet.

But let’s look at the announced characteristics of EHang 184 to assess what’s great and not so great about it. If anything, these types of drones are at least guaranteed to give you the fpv drone flight you’re looking for if you’re into that sort of thing, this is real live FPV!

Safety

So the X8 configuration is a good choice but only if configured right because I could not find any information as to how the ESC-s are placed and how many separate controllers are used, what type they are, etc. EHang does say that there are “multiple backups” in place, but what they mean is unclear. The key here is to have separate boards of redundancy where both controllers and ESCs are backed up by fallback systems. In that case, theoretically even 4 of the 8 rotors can stop and the vehicle could be able to land safely. EHang’s CEO mentioned in an interview that even if 6 motors would fail on 3 of the arms, the AAV (Autonomous Aerial Vehicles) would be able to “spiral to the ground” safely. Well, that sounds kind of scary, doubt that it would not result in anything anyone can survive. The manufacturer says that “the 184 AAV is embedded with Ehangen fail safe system” which suggests that they designed their own solution. Hope they release more information on that.

At the same time, unlike winged aircraft multirotors do not have a gliding capability and that could be a concern. I guess EHang could mount an automatically deploying parachute like a BRS chute to let the vehicle ascend safely. But if there is no such system involved and the passenger has to bail due to a malfunction, the 8 rotors being right next to the doors is a bit of a concern. I am no aircraft designer, but it would seem reasonable to place the rotor blades above the craft for added security. Placing the rotors up high would also prevent bystanders from getting injured while takeoff and landing.

Prop guards have been used on multirotors for quite some time. For example the Hoverbike is designed to have them. Why the EHang 184’s are not equipped with ducted motors is also an interesting question. It could be my ignorance and I am sure the guys over at EHang have considered that but would love to find out what the reason is.

EHang 184’s Power Supply

The 184 will have a 23 minute flight time roughly allowing a 10 mile flight as announced at CES this week. Whether that, combined with a 2-4 hour charging time is sufficient for day-to-day use depends on the owner’s personal situation, but to me it seems a little too limited. Information is scarce at this time as to the type of battery the 184 will use, but the flight time suggests Lithium Polymer and that could also be a concern to be honest. LiPo batteries are great, most UAVs use them, but they have to be handled correctly and tend to lose voltage suddenly in certain conditions such as cold weather. How you store and deplete them is also an issue, check out our guide on LiPo battery care.

Being zero emission is all great, but EHang should consider other power supply options like hybrid power (just an idea) in order to make the EHang 184 a reasonable alternative to small helicopters.

EHang 184 Control Mechanism

Now this is where it gets really scary. Reports from the EHang booth at CES say that the “pilot” or better say passenger in the cockpit will not have a chance to fly the aircraft or take over controls from the autonomous system. Well, not being able to fly the aircraft is a problem because it takes away most of the fun I would imagine owners could have owning this puppy. A system similar to waypoint flying in UAVs that simply takes you to a desired location by just clicking on it on Google Maps sounds great as an option. But only as an option. Not the only way to fly the aircraft. I know not all possible future users are multirotor fanatics but I am quite sure that the first people to get one of these would be them. And not letting them fly the damn thing seems like a really bad idea.