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!
Ehang 184 Rotors and Configuration
The EHang 184 is very similar to a multicopter UAV with an X8 configuration. bviously, a manned multicopter that would be trusted to carry a passenger can not be a quadcopter because if only one motor would malfunction, the vehicle would fall to the ground like a brick. Guaranteed.
The X8 configuration features 8 rotors placed on four arms so it combines the maneuverability and agility of a quadcopter with the redundancy of an octocopter.
So the X8 configuration is a good choice but only if configured right. 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. 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.
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.
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. 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.
Being zero emission is all great.
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.
According to the announcement, in case of emergency situations the EHang 184 will be piloted by personnel sitting in command centers somewhere and help you land safely at the “nearest possible location”. Now forget the fact that they will have to build these centers first which is mostly a matter of funds and the availability of qualified pilots that can take on the responsibility of saving someone’s life from the distance. The US already has problems with drone pilot shortages.
EHang 184 Pricing
Accorcing to reports, the 184 will cost between $200.000 – $300.000. Now a small but proven helicopter such as the Robinson R44 Raven I costs $355.000 brand new. It has a 350 mile range and can transport 3 passengers at 4000 feet. Ok, it is more expensive to operate probably, but the 184 must be a hell of a lot cheaper to manufacture too. So the pricing seems to be a little extreme.