DJI Digital FPV

[utnuc]

Hey guys, I've been thinking about getting into FPV this year ever since I started building foamies. I know that FPV is its own animal and there seems to be a bit of gear tribalism at play on forums, especially eschewing companies like DJI since they have not traditionally been a part of the DIY builder market. Further, they seem to be at odds with the FliteTest ethos of build it cheap -> fly/crash -> repeat.

Having written this, I would like to hear from the fixed wing FPV community regarding the new DJI Digital FPV system. My hesitation in jumping right into the FPV market has been the poor image quality. To get image quality with good warranty and support worthy of jumping in, I'd be looking at $300 Fat Shark goggles, then adding on a $170 Rapidfire module. Getting close to $500 already, sans camera and batteries, +adding a second camera for HD recording. Even still, I'd be looking at a grainy analog video with limited range.

The reviews on the DJI Digital FPV look promising. Pros: amazing range, HD image quality, great warranty and support, no need for a second camera. Cons: Expensive at $819 for goggles + 2 receiver/camera units, weight: 54 grams for a receiver/camera unit that runs at 4-9 watts, proprietary non-interchangeable equipment.

How would 54 grams do on one the front of one of these foam planes? If I could somehow get a lightweight betaflight controller, I could consider using the DJI controller increasing range to an insane 4km, but otherwise I'd be limited to my OrangeRX DSMX theoretical range of 1km.

On one hand it seems crazy to buy such expensive FPV equipment then put it in a foam airplane, but ultimately most of the cost will be on my face and not in my plane. Please lend your expertise and thoughts.

 

[FDS]

You don’t need a flight controller for fixed wing. They are used in FPV wings and autonomous planes, but most fixed wing pilots fly LOS or closer FPV.
I have not found image quality a problem in nearly a year of flying analog FPV, I have both a $40 set of Eachine EV800 box goggles and a set of $250 second hand Fatshark Dominator V3’s If you use a decent quality camera and a moderately good VTX you can get a great analog picture.
HD is nice and all but the bulk of the unit and huge cost are a big fat nope for me right now.
You honestly don’t need to drop $500+ to enjoy FPV, it’s possible to add it to a fixed wing set up for under $100.
Flying beyond line of sight is illegal in many countries as well. I haven’t found the need to fly beyond the range of either my 2.4ghz systems (Orange TX6I and Taranis) or my “long range” system which could go out to 10km.
The DJI system is fine if you want only the best equipment, you would nearly spend that on top tier analog but you do not need any of that stuff to dive in and enjoy it.

 

[ElectriSean]

You don’t need a flight controller for fixed wing. They are used in FPV wings and autonomous planes, but most fixed wing pilots fly LOS or closer FPV.

I believe you do need a FC to use the DJI controller, I don't think it can output PWM for servos. The main advantage to an FC in a fixed wing IMHO is the OSD, which you can't use with the DJI camera either...

If all you're doing is fixed wing I think you're much better off with an analog FPV system, especially if you're just starting out. I'd hate to drop that kind of coin just to find out I don't like it, or that it makes me sick (it happens to some people). Image quality under the hood is always better than the DVR footage people post, and with decent antennae you can out range the DJI system easily.

 

[utnuc]

Thanks for the words of wisdom, @FDS and @ElectriSean. I'll admit that I have a tendency to go overboard when first getting into something new (just ask my wife re: when I was optioning out my car). Perhaps a more measured approach would work best. I guess I should aslo start looking at the pusher planes as the best fpv platform...

Oh, one other note, Fat Shark apparently announced a digital platform this month also. It'll be interesting to see where the industry goes with some competition.

 

[FDS]

The DJI system will work without their controller. You can just use the video part and goggles.
I won’t be considering HD FPV gear until the second generation equipment comes out.

 

[CarolineTyler]

Since the DJI controller outputs SBUS you could always use a cheap SBUS converter to get your servo outputs and make use of the controller. It would make for a neater installation.

 

[Corbarrad]

The biggest hope I have for these new digital systems is that they'll raise the number of available channels at an event.
I hope they'll do for FPV what FHSS systems did for Radio control, eliminate the need for frequency management by the users.
That will make FPV events so much more relaxed.

 

[utnuc]

@CarolineTyler good point. Silly question: would the SBUS converter be a 1:1 match for the fixed wing channels, eg throttle/rudder/elevator/ailerons? I assume this would be limited to 4 channels, so nothing fancier than that?

 

[CarolineTyler]

@CarolineTyler good point. Silly question: would the SBUS converter be a 1:1 match for the fixed wing channels, eg throttle/rudder/elevator/ailerons? I assume this would be limited to 4 channels, so nothing fancier than that?

The units break out 8 channels each and two can be used to break out a full 16 channels!

 

[utnuc]

Looks like Fat Shark is delaying their Frost Byte system because they want to improve on it after seeing DJI's offering. Reddit Fat Shark Announcement

 

[FDS]

The SBUS signal will output the channels in whatever order the transmitter has them, so 1-4 on Spektrum would be Throttle, Aileron , Elevator, Rudder and on FRsky it would be Aileron, Elevator, Throttle, Rudder, unless you used OpenTx to change the orders. Channel order is entirely set by radio manufacturers, SBUS is just a way of getting multiple channels through 3 wires instead of needing ground, 5v and signal from each channel. It doesn’t care what the output is used for. The converter then turns the SBUS signal into the PWM wave needed to move a servo.

 

[utnuc]

@FDS So the advantage would be no need for another receiver on board, saving that space (although that would be somewhat negated by the sbus converter). Probably some additional range. I don't think there would be any additional HUD advantage to having all dji equiptment. Disadvantage would be having to buy and use the proprietary $300 DJI controller.

Either way space would definitely be an issue in one of the FT minis. The dji receiver width of 4 cm would fit OK in the FT Goblin, but would just barely fit in the Mighty Mini Arrow. (I've gotten a 3 axis gyro to fit)