Review: Diatone GT-R239 (2019 R90 Rabbit) 2inch 3S Micro Quad

Diatone keeps on improving their R90 series micro drone, and it’s just getting more affordable and durable! This model is intended as a starter quadcopter for new pilots. But I also see potential as a platform for installing a split-mini style camera for HD recording.

It’s Tough!

I spent some time stress testing the Diatone R239 but it just wouldn’t break :) The video shows how much torture it went through in just one of the batteries.

Where To Buy?

This is a PNP (Plug and Play) model, which means you will need your own battery and radio receiver.

The package includes the following accessories:

  • Info cards for wiring diagram + FC pin-out
  • Buzzer
  • Various screws
  • 5 zip ties
  • 5 battery sticky pads
  • Spare XT30 female connector
  • Spare connector between FC and 4in1 ESC
  • Diatone stickers

Spec and Features

The new R239, aka 2019 R90, has been refined, in fact, redesigned, from the previous model, the 2018 R90 that we reviewed back in 2017. They addressed the few issues we raised in the last review, and also made some improvements on the spec.

Not sure what happened to the naming of this model, or maybe Diatone couldn’t decide what name to give it :) Is it called “2019 GT R90”, “Rabbit” or “R239”? I will just call it the “R239” in the rest of this review.

Here is the basic spec of the quad.

Features:

  • Up to 8K Looptime
  • Supports Betaflight OSD
  • 16MB Flash Memory for Blackbox
  • 5V 2A BEC
  • VTX Control with Tramp Telemetry
  • Onboard Current Sensor

Sizes and Weight:

  • Wheelbase 95mm, our measurement is larger than the claimed 90mm
  • Length & Width including prop guard: 115mm x 140mm
  • Weight without battery: 87g (with R-XSR receiver installed)

For a micro quad swinging 2-inch props, this is quite heavy to be honest. 60g to 70g is the “common” weight for a 2-inch quad. I think the extra weight mostly come from the frame since there is extra material used for the prop guard?

Get Spare Props!

It comes with only a set of Gmefan 1940×3 props, so you definitely should get some spare! Even with the prop guard, your props are still possible to get damaged in a crash because of how flexible the frame is.

Batteries for the R239

I’ve been told this machine perform the best with 3S 400mAh – 450mAh LiPo.

After some testing I noticed battery size does affect the flight performance a lot on these tiny quads. I tried some 3S 650mAh, and it just didn’t fly well at all – it was just sluggish and unresponsive, and hovers at over 55% throttle, it was also difficult to recover from a roll.

The heavier weight is likely to make the quad less durable too due to bigger impact in crashes.

550mAh is probably the biggest you should use as far as capacity goes for this model if you want longer flight time, but I’d probably still recommend 450mAh.

Radio Receiver

It’s a plug and play model, so you’d need to install your own RX. The R239 already has a cable soldered to the FC, which I find you can plug straight into the Frsky R-XSR. That would be my go-to receiver option if you are using a Taranis.

Buy R-XSR:  Banggood | Amazon | HorusRC

Super Tough Frame!

I don’t know exactly what the material is that they used to make the frame, it feels like polycarbonate – a flexible but very tough plastic.

The prop guards are built into the frame so you can’t remove them. The problem with this design is that if one of the struts breaks, you would have to replace the whole frame.

It’s quite a bendy frame, and speaking from experience this might introduce bad oscillations. I am hoping this is less of a problem for a micro quad of this light weight.

Diatone is selling this frame separately as a kit for £4. Worth considering if you are a beginner and just want something that is crash-resistant. Available Colors are black, white, and transparent.

The plastic frame provides excellent protection to the electronics. But due to the flexible nature of the frame, when you hit something hard, your propellers might take some impact as well and get bent. Therefore it’s a good idea to get spare props.

However, as explained in our “flying in winter” guide, plastic becomes brittle and easier to break in the cold. If you live somewhere cold you might want to take it easy with this model :)

Close Look at the Diatone R90 Rabbit

The Mamba F4 Mini FC is soft-mounted by rubber grommets, sitting on top of a 25A 4in1 ESC. It’s a BLHeli_S ESC but capable of running DShot600 protocol.

The stack is secured by four long Phillip screws from the bottom all the way to the top, quite a neat design. It’s good to see that Diatone finally replaced those fragile nylon screws for the stack in the previous R90.

However I do wish they could standardize the use of hardware in the quad – i.e. use all hex screws.

There seems to be enough room in the frame for another board… Maybe the Runcam Split Mini 2? :D That’s what I am going to do next!

In case you need a reference to the FC pin-out, here are the leaflets included.

The camera is a Runcam Micro Swift V1. This must be a special edition because it has a green case I’ve never seen before, almost mistaken for a Caddx :) Camera is well protected by the frame.

On the back of the camera we have the Runcam TX200U video transmitter, which is a 25mW/200mW VTX with Tramp Telemetry capability. With this feature, you can change VTX settings using Betaflight OSD as well as Taranis LUA script, more detail here.

However, the FPV camera tilt angle seems to be limited at around 20 degrees as you can see in the picture. The frame/camera slot allows for a higher up-tilt, but there is no more room between the VTX and FC stack.

Motors are the Mamba 1105 5500KV, with Gemfan 1940×3 props. All the installed and spare screws have loctite on them which is great touch. It’s good to finally see some “proper propellers” rather than “toy grade” props from the last version.

This quad is only rated for 3S, not 4S. I am not sure if this is due to the component limitation, or the flexible frame might not be able to handle the higher power / heavier of 4S battery?

I remember the previous R90 could take 4S and it was fine (which has even higher KV motors at 6000KV). Anyway 3S is still very fast and actually more optimal thanks to the lighter batteries.

Here is a side by side size comparison to another 2-inch micro quad I recently reviewed – the iFlight iH2.

Hardware Setup

The R239 is so much easier to setup than the last version! It came pre-built out of the box, all you have to do is to plug in your own receiver and you are good to go!

But somehow they left out the SmartPort wire in the cable, not sure if that’s intentional. Because it can be a bit tricky to setup SmartPort on an F4 FC due to the inverted signal, maybe they are trying to avoid it?

Anyway I just connected the RX to the FC without the SmartPort wire. I won’t be using telemetry on this model because Betaflight OSD can do pretty much everything I need anyway.

Oh, remember to plug in the provided buzzer and strap it to the arm with a zip tie. Finally, install the props on, and that’s pretty much all you have to do with the hardware.

Software Setup and Tuning

The FC comes with Betaflight 3.5.1 pre-installed.

Two UART Ports are used:

  • UART1 – Serial RX
  • UART3 – IRC Tramp for VTX Control

Here are the things I did for the first flight:

These are the settings I was given by Diatone. I will update these to my own settings once I’ve found a good tune.

set dyn_notch_quality = 5
set dshot_idle_value = 300
set motor_pwm_protocol = DSHOT600
set current_meter = ADC
set small_angle = 60
set dterm_lowpass_hz = 80
set dterm_lowpass2_hz = 160
set dterm_notch_cutoff = 0
set vbat_pid_gain = ON
set iterm_rotation = OFF
set iterm_relax = RP
set iterm_relax_type = SETPOINT
set throttle_boost = 0
set p_level = 150
set level_limit = 35
set tpa_breakpoint = 1750

PID for 400mAh – 450mAh 3S LiPo (provided by Diatone)

set p_pitch = 60
set i_pitch = 10
set d_pitch = 30
set f_pitch = 5
set p_roll = 50
set i_roll = 10
set d_roll = 30
set f_roll = 60
set p_yaw = 58
set i_yaw = 25
set d_yaw = 0
set f_yaw = 70

PID for 550mAh 3S LiPo (provided by Diatone)

set p_pitch = 55
set i_pitch = 10
set d_pitch = 30
set f_pitch = 5
set p_roll = 44
set i_roll = 20
set d_roll = 30
set f_roll = 60
set p_yaw = 45
set i_yaw = 55
set f_yaw = 90

Once you have loaded up the settings and PID, then go on and setup rates. Note that rates are very much personal preference. What I have now, not finalised.

  • Pitch/Roll Rate 1.28, Super Rate 0.67, Expo 0.22
  • Yaw Rate 1.25, Super rate 0.66, Expo 0.25

“Unlock” TX200U

Beware that the VTX, Runcam TX200U came “locked”, which means half of the channels are unavailable and output power is limited to 25mW. It simply won’t work when you select one of the “locked” channels, or 200mW, it will simply stay at it’s last channel and 25mW.

You could “unlock” it, simply by holding down the button for 10 seconds.

Flight Testing

This is an early test sample, so obviously there is still work to do. After a couple of flights, I found it still needs a lot of tuning, not just PID, but filters, throttle boosts and all those settings need reworked.

And as I mentioned I was using 3S 650mAh battery which is way too heavy according to Diatone. That’s why it felt very under-powered and unresponsive. I had to buy some new 450mAh batteries so hopefully I get to test it again and report back in a few days.

Conclusion

Not yet… I haven’t finished testing this machine. But here is what I think so far… Will come back and update it as I learn more. Hopefully with all the feedback from reviewers, Diatone can make a beautiful product and when you get yours it will just fly amazing out of the box. But if I can’t make this thing fly well, I will also tell you about it in my review :)

Pros

  • Extremely durable frame with prop guard, great for beginners, as it simply doesn’t care about crashes
  • Well-thought-out design with excellent build quality
  • Very cheap for the versatility! This is a 3S micro quad and has the potential for multiple applications
  • Upgradable! As you progress with skills, you can later move the components over to a 2.5-inch carbon fibre frame, lighter frame + bigger props = more power and faster!
  • It has buzzer!

Cons

  • In my opinion, the frame is a bit too flexible which affects “tune-ability” and flight performance
  • A bit on the heavy side – Not a racer if that’s what you are looking for
  • Flight performance cannot compare to a 5″, or even a 3″ in that matter. After all it’s only spinning 2″ props! It’s not a racer, but more of a slow cruiser

Update (12 Dec 2018)

My unit seems to be defective, it pitches backward randomly and I think it’s either the FC, ESC or motors aren’t working. I have sent it back to Diatone and see if they can replace it for me.

Update (04 Jan 2019)

Yay! Got a replacement, and it seems working as expected now.

Here is my PID:

set p_pitch = 33
set i_pitch = 45
set d_pitch = 31
set f_pitch = 60
set p_roll = 28
set i_roll = 37
set d_roll = 31
set f_roll = 65
set p_yaw = 60
set i_yaw = 90
set d_yaw = 0
set f_yaw = 85

And I uploaded a video of some flying at the beginning of the video.

Update (15 Jan 2019)

Someone asked me for the CLI dump. Here is the diff dump of my quad.

# feature
feature AIRMODE

# serial
serial 2 8192 115200 57600 0 115200

# aux
aux 0 0 0 1700 2100 0 0
aux 1 1 1 1700 2100 0 0
aux 2 13 2 1225 2100 0 0

# master
set dyn_notch_quality = 5
set min_check = 1010
set dshot_idle_value = 300
set motor_pwm_protocol = DSHOT600
set current_meter = ADC
set small_angle = 60
set deadband = 2
set yaw_deadband = 2
set pid_process_denom = 1
set osd_warn_core_temp = OFF
set osd_cap_alarm = 500
set osd_vbat_pos = 2497
set osd_tim_1_pos = 2519
set osd_tim_2_pos = 471
set osd_throttle_pos = 2476
set osd_vtx_channel_pos = 2048
set osd_current_pos = 2507
set osd_mah_drawn_pos = 2465
set osd_craft_name_pos = 2070
set osd_pidrate_profile_pos = 409
set osd_avg_cell_voltage_pos = 385
set vtx_band = 5
set vtx_channel = 3
set vtx_freq = 5732

# profile
profile 0

set dterm_lowpass_hz = 80
set dterm_lowpass2_hz = 160
set dterm_notch_cutoff = 0
set vbat_pid_gain = ON
set anti_gravity_gain = 6000
set feedforward_transition = 30
set iterm_rotation = OFF
set smart_feedforward = ON
set iterm_relax = RP
set iterm_relax_type = SETPOINT
set throttle_boost = 0
set p_pitch = 33
set i_pitch = 45
set d_pitch = 31
set p_roll = 28
set i_roll = 37
set d_roll = 31
set f_roll = 65
set p_yaw = 50
set i_yaw = 90
set f_yaw = 85
set p_level = 150
set level_limit = 35

# rateprofile
rateprofile 0

set thr_mid = 100
set thr_expo = 1
set roll_rc_rate = 120
set pitch_rc_rate = 120
set yaw_rc_rate = 115
set roll_expo = 22
set pitch_expo = 22
set yaw_expo = 25
set roll_srate = 68
set pitch_srate = 64
set yaw_srate = 68
set tpa_rate = 25
set tpa_breakpoint = 1750

14 thoughts on “Review: Diatone GT-R239 (2019 R90 Rabbit) 2inch 3S Micro Quad

  1. Tyler

    I’ve been using spektrum spm4648 receivers since I started fpv. Would it be compatible with this stack? I see it has a 3.3v pad. Which pad would I use for signal? I’m saving for fatsharks before switching to frsky so I’m trying to use what I have for now. Thanks for any help you can offer

    Reply
    1. SmartFOX-feiniaoyi

      hey,Thank you for making such a good reviewing.
      I am the pilot provided the original pid, but the parameter seem to have some problem.

      I retest for a long-time , find a new pid.

      Roll P=22,I=25,D=25
      Pitch P=27,I=20,D=27
      Yaw P=50,I=100

      For betaflight3.5.2 firmware, it’s ok and less flying pitch back.

      Reply
      1. Oscar Post author

        I don’t really have pitch back anymore.. I think the problem must be just hardware, Diatone replaced it for me and that doesn’t happen anymore.
        I tried your PID’s too, and I slightly raised the numbers for a tighter feel :)

  2. Bianca

    I have the Gt-M3, will the stack fit inside this frame? I’m not good enough to fly the gt-m3 so changing to the GT-R239 is better for me i think. And it will save me money :)

    Best regards, Bianca
    The Netherlands

    Reply
    1. Oscar Post author

      The GT-M3 is a 3″ quad while the R239 is a 2″ :)
      I’d avoid the R239 frame after I tested it. It’s very hard to tune and doesn’t have the desired flight characteristics. Beginners or indoor flyers might appreciate it though given how tough it is.

      Reply
  3. Mann Perete

    I have the same fc/esc combo on my r349. Esc was damaged I strongly believe was because of an exposed motor wire that was sitting under the esc. That motor was getting warm when the rest were cool. Diatone replaced only the motor because I already took the quad apart – I was told it was damage due to crashing. I would be happier if they sent me an esc instead to be honest.

    Reply
  4. Pipo

    Is there any noise in the FPV feed?

    I have the original GT-R90 and the GT-M3 and both quads are extremly noisy. Both quads use the Fury F4 board with Mamba ESC. To be honest, im not a big fan of the FC or ESC they used.

    Reply

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