Post Syndicated from Evan Ackerman original https://spectrum.ieee.org/automaton/robotics/drones/review-djis-new-fpv-drone-is-effortless-exhilarating-fun
An FPV drone is a drone that you fly from a first-person viewpoint. The drone has a forward-facing camera that streams video to a pair of goggles in real time. This experience is a unique one, and there’s only so much that I can do to describe it, but it turns flying a drone into a much more personal, visceral, immersive thing. With an FPV drone, it feels much more like you are the drone.
DJI’s FPV drone itself is a bit of a chonker, as far as drones go. It’s optimized for going very fast while giving you a good first-person view, and no concessions are given to portability. It weighs 800g (of which 300 is the battery), and doesn’t fold up even a little bit, although the props are easy to remove.
Top speed is a terrifying 140 km/h, albeit in a mode that you have to unlock (more on that later), and it’ll accelerate from a hover to 100 km/h in two seconds. Battery life maxes out at 20 minutes, but in practice you’ll get more like 10-15 minutes depending on how you fly. The camera on the front records in 4K at 60 FPS on an electronically stabilized tilt-only gimbal, and there’s a microSD card slot for local recording.
We’re delighted to report that the DJI FPV drone also includes some useful sensors that will make you significantly less likely to embed it in the nearest tree. These sensors include ground detection to keep the drone at a safe altitude, as well as forward-looking stereo-based obstacle detection that works well enough for the kinds of obstacles that cameras are able to see.
What really makes this drone work are the FPV goggles along with the radio system that connects to the drone. The goggles have two tiny screens in them, right in front of your eyeballs. Each screen can display 1440 x 810p at up to 120 fps (which looks glorious), and it’ll do so while the drone is moving at 140 km/h hundreds of meters away. It’s extremely impressive, with quality that’s easily good enough to let you spot (and avoid) skinny little tree branches. But even more important than quality is latency— the amount of time it takes for the video to be captured by the drone, compressed, sent to the goggles, decompressed, and displayed. The longer this takes, the less you’re able to trust what you’re seeing, because you know that you’re looking at where the drone used to be rather than where it actually is. DJI’s FPV system has a latency that’s 28ms or better, which is near enough to real-time that it feels just like real-time, and you can fly with absolute confidence that the control inputs you’re giving and what you’re seeing through the goggles are matched up.
The goggles are also how you control all of the drone options, no phone necessary. You can attach your phone to the goggles with a USB-C cable for firmware updates, but otherwise, a little joystick and some buttons on the top of the goggles lead you to an intuitive interface for things like camera options, drone control options, and so on. A microSD card slot on the goggles lets you record the downlinked video, although it’s not going to be the same quality as what’s recorded on-board the drone.
Don’t get your hopes up on comfort where the goggles are concerned. They’re fine, but that’s it. My favorite thing about them is that they don’t weigh much, because the battery that powers them has a cable so that you can keep it in your pocket rather than hanging it off the goggles themselves. Adjustable straps mean the goggles will fit most people, and there’s inter-eye distance adjustments for differently shaped faces. My partner, who statistically is smaller than 90% of adult women, found that the google inter-eye distance adjustment was almost, but not quite, adequate for her. Fortunately, the goggles not being super comfortable isn’t a huge deal because you won’t be wearing them for that long, unless you invest in more (quite expensive) battery packs.
The last piece of the kit is the controller, which is fairly standard as far as drone controllers go. The sticks unscrew and stow in the handles, and you can also open up the back panels to adjust the stick tension, which experienced FPV pilots will probably want to do.
Before we get to how the drone flies, a quick word on safe operation— according to the FAA, if you’re flying an FPV drone, you’ll need a spotter who keeps the drone in view at all times. And while the range of the DJI FPV drone is (DJI claims) up to 10km, here in the United States you’re not allowed to fly it higher than 400ft AGL, or farther away than your spotter can see, without an FAA exemption. Also, as with all drones, you’ll need to find places that are both safe and legal to fly. The drone will prevent you from taking off in restricted areas that DJI knows about, but it’s on you to keep the drone from flying over people, or otherwise being dangerous and/or annoying.
In Flight— Normal Mode
DJI has helpfully equipped the FPV drone with three flight modes: Normal, Sport, and Manual. These three modes are the primary reason why this drone is not a terrible idea for almost everyone— Normal mode is a lot of fun, and both safe and accessible for FPV novices. Specifically, Normal mode brings the top speed of the drone down to a still rather quick 50 km/h, and will significantly slow the drone if the front sensors think you’re likely to hit something. As with DJI’s other drones, if you start getting into trouble you can simply let go of the control sticks, and the drone will bring itself to a halt and hover. This makes it very beginner friendly, and (as an FPV beginner myself) I didn’t find it at all stressful to fly. With most drones (and especially drones that cost as much as this one does) fear of crashing is a tangible thing always sitting at the back of your mind. That feeling is not gone with the DJI FPV drone, but it’s reduced so much that the experience can really just be fun.
To be clear, not crashing into stuff is not enough to make FPV flying an enjoyable experience. Arguably the best feature of DJI’s FPV drone is how much help it gives you behind the scenes to make flying effortless.
When flying a conventional drone, you’ve got four axes of control to work with, allowing the drone to pitch, roll, yaw, move vertically up and down, or do any combination of those things. Generally, a drone won’t couple these axes for you in an intelligent way. For example, if you want to go left with a drone, you can either roll left, which will move the drone left without looking left, or yaw left, which will cause the drone to look left without actually moving. To gracefully fly a drone around obstacles at speed, you need to fuse both of these inputs together, which is a skill that can take a long time to master. I have certainly not mastered it.
For most people, especially beginners, it’s much more intuitive for the drone to behave more like an airplane when you want it to turn. That is, when you push the left stick (traditionally the yaw control), you want the drone to begin to roll while also yawing in the same direction and increasing throttle to execute a lovely, sweeping turn. And this is exactly what DJI FPV does— thanks to a software option called coordinated turns that’s on by default, the drone does exactly what you think it should do, and it works beautifully.
I could tell you how well this works for me, someone who has flown non-FPV drones for years, but my partner has flown a drone only one single time before, when she spent five minutes with the controller of my Parrot Anafi a few years ago and got it to go up and down and occasionally sideways a little bit. But within literally two minutes, she was doing graceful figure 8s with the DJI FPV drone. The combination of the FPV view and the built-in coordinated turns makes it just that intuitive.
In Flight— Sport Mode
Once you’re comfortable with Normal mode, Sport mode (which you can select at any time with a toggle switch on the controller) bumps up the speed of the drone from 50 km/h to 97 km/h. More importantly, the obstacle avoidance no longer slows the drone down for you, although it does give you escalating warnings when it thinks you’re going to hit something. As you get more comfortable with the drone, you’ll find that the obstacle avoidance tends to be on the paranoid side, which is as it should be. Once you’ve practiced a bit and you want to (say) fly between two trees that are close together, Sport mode will let you do that without slowing down.
Along with a higher top speed, Sport mode will also make the drone literally scream. When in flight it makes a loud screaming noise, especially when you ask a lot from the motors, like with rapid direction changes or gaining altitude at speed. This happens in Normal mode, but gets markedly louder in Sport mode. This doesn’t matter, really, except that if you’re flying anywhere near other people, they’re likely to find it obnoxious.
I was surprised by how not-puking I was during high-speed FPV flight in Sport mode. I tend to suffer from motion sickness, but I had no trouble with the drone, as long as I kept my head still. Even a small head movement while the drone was in flight could lead to an immediate (although minor) wave of nausea, which passed as soon as I stopped moving. My head sometimes subconsciously moved along with the motion of the drone, to the point where after a few minutes of flying I’d realize that I’d ended up staring sideways at the sky like an idiot, so if you can just manage to keep your head mostly still and relaxed in a comfortable position, you’ll be fine.
A word on speed— even though Sport mode has a max speed of only (only?) 97 km/h, coming from flying a Mavic Pro, it feels very, very fast. In tight turns, the video coming through the goggles sometimes looked like it was playing back at double speed. You could always ask for more speed, I suppose, and Manual mode gives it to you. But I could see myself being perfectly happy to fly in Sport mode for a long, long time, since it offers both speed and some additional safety.
The following video includes clips of Normal and Sport mode, to give you an idea of how smooth the drone moves and how fast it can go, along with a comparison between the standard 1080p recorded by the drone and what gets shown in the goggles. As you watch the video, remember that I’m not an FPV pilot. I’ve never flown an FPV drone before, and what you’re seeing is the result of less than an hour of total flight time.
In Flight— Manual Mode
There is one final mode that the DJI FPV drone comes with: Manual mode. Manual mode is for pilots who don’t need or want any hand-holding. You get full control over all axes as well as an unrestricted top speed of 140 km/h. Manual mode must be deliberately enabled in menus in the goggles (it’s not an available option by default), and DJI suggests spending some time in their included simulator before doing so. I want to stress that Manual mode doesn’t just disable the coordinated turns function, making control of the drone more like a traditional camera drone— if that’s something you want, there’s an option to do that in Normal and Sport mode. Manual mode is designed for people with drone racing experience, and enabling it turns the FPV drone into a much different thing, as I found out.
My test of Manual mode ended approximately 15 seconds after it began due to high speed contact with the ground. I wouldn’t call what happened a “crash,” in the sense that I didn’t fly the drone into an obstacle— there was a misunderstanding or a lack of information or an accidental input or some combination of those things that led to the drone shutting all of its motors of at about 150 feet up and then falling to the ground.
I’d planned to just fly the drone in Manual mode a little bit, with plenty of altitude and over a big open space, primarily to get a sense of how much faster it is in Manual mode than in normal mode. After taking off in Normal mode and giving the drone a lot of room, I switched over to Manual mode. Immediately, the drone began to move in a much less predictable way, and after about five seconds of some tentative control inputs to see if I could get a handle on it, I felt uncomfortable enough to want the drone to stop itself.
The first thing I did was stop giving any control inputs. In Normal and Sport mode, the drone will respond to no input (centered sticks) by bringing itself to a hover. This doesn’t happen in Manual mode, and the drone kept moving. The second thing I did was push what I thought was the emergency stop button, which would switch the drone back to Normal mode and engage a thoughtfully included emergency stop mode to bring it to a stable hover as quickly as possible. I hadn’t yet needed an emergency stop in Normal or Sport mode, since just taking my fingers off of the sticks worked just fine before. What I learned post-crash was that in Manual mode, the button that says “Stop” on it (which is one of the easiest to press buttons on the controller since your right index finger naturally rests there) gains a new emergency shut-off functionality that causes the drone to disable all of its motors, whereupon it will then follow a ballistic trajectory until the inevitable happens no matter how much additional button pushing or frantic pleading you do.
I certainly take some responsibility for this. When the DJI FPV drone showed up, it included a quick start guide and a more detailed reviewer’s guide, but neither of those documents had detailed information about what all the buttons on the controller and headset did. This sometimes happens with review units— they can be missing manuals and stuff if they get sent to us before the consumer packaging is complete. Anyway, having previous experience with DJI’s drones, I just assumed that which buttons did what would just be obvious, which was 100% my bad, and it’s what led to the crash.
Also, I recognize why it’s important to have an emergency shut-off, and as far as I know, most (if not all) of DJI’s other consumer drones include some way of remotely disabling the motors. It should only be possible to do this deliberately, though, which is why their other drones require you to use a combination of inputs that you’re very unlikely to do by accident. Having what is basically a self-destruct button on the controller where you naturally rest a finger just seems like a bad idea— I pushed it on purpose thinking it did something different, but there are all kinds of reasons why a pilot might push it accidentally. And if you do, that’s it, your drone is going down.
DJI, to their credit, was very understanding about the whole thing, but more importantly, they pointed out that accidental damage like this would be covered under DJI Care Refresh, which will completely replace the drone if necessary. This should give new pilots some piece of mind, if you’re willing to pay for the premium. Even if you’re not, the drone is designed to be at least somewhat end-user repairable.
Fundamentally, I’m glad Manual mode is there. DJI made the right choice by including it so that your skill won’t outgrow the capabilities of the drone. I just wish that the transition to Manual mode was more gradual, like if there was a Sport Plus mode that unlocked top speed while maintaining other flight assistance features. Even without that, FPV beginners really shouldn’t feel like Manual mode needs to be a goal— Normal mode is fun, and Sport mode is even more fun, with the added piece of mind that you’ve got options if things start to get out of your control. And if things do get out of your control in Manual mode, for heaven’s sake, push the right button.
I mean, the left button.
Is This The Right Drone for You?
DJI’s FPV drone kit costs $1,299, which includes the drone, goggles, one battery, and all necessary chargers and cabling. Two more batteries and a charging hub, which you’ll almost certainly want, adds $299. This is a lot of money, even for a drone, so the thing to ask yourself is whether an FPV drone is really what you’re looking for. Yes, it’ll take good quality pictures and video, but if that’s what you’re after, DJI has lots of other drones that are cheaper and more portable and have some smarts to make them better camera platforms. And of course there’s the Skydio 2, which has some crazy obstacle avoidance and autonomy if you don’t want to have to worry about flying at all. I have a fantasy that one day, all of this will be combined into one single drone, but we’re not there yet.
If you’re sure you want to get into FPV flying, DJI’s kit seems like a great option, with the recognition that this is an expensive, equipment-intensive sport. There are definitely ways of doing it for cheaper, but you’ll need to more or less build up the system yourself, and it seems unlikely that you’d end up with the same kind of reliable performance and software features that DJI’s system comes with. The big advantage of DJI’s FPV kit is that you can immediately get started with a system that works brilliantly out of the box, in a way that’s highly integrated, highly functional, high performing while being fantastic for beginners and leaving plenty of room to grow.