The Diatone 2019 GT R249+ is one of the newest series of micro quadctopers from Diatone that is built around the Mamba mini f4 stack.
The full range from smallest to largest includes:
As you can see there is a high degree of modularity - for all except the largest they share the same 1105 5500kV motors. All sizes feature a 3mm thich carbon baseplate except for the R239 which uses and injection moulded plastic chassis and prop-gaurds. All models share the same injection moulded lightweight canopy and mamba mini f4 stack.
I've chosen to review the R249+ since my experience with micro quadcopters has lead me to believe that this is the 'sweet' spot in terms of performance and staying small and discrete when flying.
Overall look and feel
The first thing I'll say is that this is a very polished looking quadcopter. The build is well put together and includes some thoughtful parts like buzzer, spare screws, cable ties etc. although sadly only one set of propellers are included. Most impressive is perhaps the canopy that ties everything together. This is not a 3d printed canopy (like on the Leader 2.5) but an injection moulded one meaning a tidier finish and lighter weight as well as providing much more torsional strength. The design is clever and ingregrates with the quad well and includes well though-out features like the camera protection moulded in. The canopy is common across all of their 2019 GT range and is available in clear, white or black. No doubt other colours will be available later too. A quick shout out that the kit also includes 2 battery straps - these are my new favourites - lightest I've come across at a hair over 2g and 150mm long.
A closer look at the specs (my comments in red)
Wheel base: 115mm A good tight frame for 2.5" props. carbon fibre thickness is 3.0mm
Propeller: 2.5 inch. These are gemfan 2540 props, simply the best 2.5" prop available
Color: lucency / black / white
Weight: 77g This is the weight without receiver or props. Weight with receiver, props, battery strap is just under 83g.
Lipo battery: support 4S (not included) Can support 4s but I feel more comfortable with 3s on 5500kV
Flight controller: Mamba F405 mini; MPU6000; AT7456 OSD; 16M flash; 5V 1A BEC. Very pleased for this to have F4 and blackbox flash for tuning. 1 spare UART available outside those used for receiver and vtx control
ESC: Mamba F25 / 25A 4S ESC Dshot600 2-4s capable. Pleasantly suprised that this has a current sensor - my first 20 x 20mm ESC to have one.
Motor: Mamba Racing MB1105 5500KV Good kV choice for 3s. These are made by BBB (3BR) - a well recognised motor manufacturer
Camera: RunCam Micro Swift. The original micro CCD cam and still very capable. A testament to reliability
VTX: RunCam TX200U 48CH 25 / 200mW - Piggback VTX that runs off 5v. Has OSD control. Needs unlocking - more below.
Setup prior to flying
Before anything else I'd recommend unlocking the video transmitter which is a Runcam TX200U. By default this is locked to 25mW transmission power and many of the channels cannot be accessed. By holding down the button for 10 seconds you can unlock the vtx meaning all available channels plus 200mW transmission power will be available via betaflight OSD (tramp protocol).
Next you'll need to add your own receiver and I use the XM+ (FRSKY) fairly exclusively. I don't use telemetry because the XM+ has a great feature that sends RSSI over an auxilliary channel so that it can be displayed in betaflight OSD (once firmware is updated). It's cheap too - Hobbycool.com have this permanently on sale at less than $10 here. Its very easy to wire up with the flight controller already pre-wired. The receiver can then easily be stuck to the top of the flight stack thanks to the plastic cover that is included.
Lastly I've captured the default betaflight settings below both in screenshot form and as a diff file but spoiler: This tune is awful, at least the version I have. Further down in the flight section I'll show updated screens and diff file.
First flight impressions?
Awful! After getting excited that there was a custom tune I was very disappointed to find out this tune was just rubbish. I switched to stock PIDs in betaflight OSD but this was even worse. I think someone has much about with the filters meaning it oscillates like crazy, even with extremely low (single digit!) P and D values on pitch and roll.
Resetting betaflight and next flight
Before taking to the sky again I updated to betaflight 3.5.3 but more importantly, reset all the custom settings. I then followed the betaflight 3.5 tuning guide here to enable all of my favourite settings like I-term relax and RC interpolation. Screenshots on the tune below and a diff file as well.
After tuning (using Albert Kim's betaflight tuning guide) I managed to get rid of the oscillations but still have some work to do in tightening it up. All of my tuning was done with a GNB 3s 450mah battery which I feel is a good match although anything up to about 650mah 3s would offer a little more flight time without compromising performance too much. Update: I now have my final tune in the gallery above. I'm pretty happy with it on 3s. It's conservative but not osciallation or Jello. Please make sure you run PID loop at no more the 4kHz.
The first thing I noticed about this quad it how quiet it is. I think this is because it is lighter than most and props aren't spinning as fast running 3s on a mid kV motor. Although not as quick as the Leader 2.5 (reviewed here) it was a lot more gentle on the battery meaning I could get a fairly comfortable 2.5-3 minutes from the 3s 450mah battery with low and fast flying which is reasonably intensive for a battery (vs. say floaty freestyle). That said I found throttle on this very linear with plenty of thrust up high in the throttle range where I'm used to it levelling off and just making more noise. Grip, cornering is all getting familiar now and assuming nothing strikingly wrong with the quad is more down to the software setting and tune than anything else. In terms of feel thought with was really good and given I have a preference for lower kV and lighter weight this suited my tastes well.
Although I prefer this quad with 3s it can most definitely handle 4s. I used my China Hobby Line Ministar 4s 650mah battery and dropped Ps and Ds a little to compensate. It is noticeably faster but I'm not a fan of this flying style where it is hard to scrub off momentum in a corner - it essentially becomes a flying bring (albeit a very fast flying brick). I'd still recommend 4s for wider open spaces if this is your only quad and yes it will perform well but I personally think wide open spaces are more suitable for larger quads. Again this is my bias showing through but I like this R249+ best on 3s and threading through smaller and more technical gaps. If you are looking for a 4s battery for this though I'd recommend a light 4s 450mah like this one from china hobby line. Update: PIDs finalised for 4s. I did quite a bit of work with D to make sure that motors were only slightly warm with a full, hard run on 4s 650mah.
Since I unlocked the VTX above, all of my flights have been on 200mW. Performance is good but not great. At first I was really impressed by the runcam VTX but after more high throttle runs I found out that there was noise coming through at high throttle. Given the runcam TX200u runs off the 5v supplied by the flight controller, the flight controllers' BEC may well be the culprit which is typical - this is what I found with the Leader 120 when I ran the vtx off the 5v line compared to battery voltage. Unfortunately though the TX200u only runs on 5v. Don't get me wrong though, it was fine, just not as clean as the Leader 2.5 or babyhawk R
Comparison to other 2.5" micros
The 2.5" brushless micro market is now relatively crowded so it's hard to stand out. I've been lucky enough to review a number of these so feel like I am in a good position to make these comparisons. There is enough differences between them in weight and motor spec to suggest some maybe more suitable than others (particularly if you have existing batteries you wish to use) but for a large part they are interchangeable.
So you can see by comparison this is relatively light for a modern 2.5" micro, only the Leader 120 is lighter. The components on the Leader 120 are now getting rather dated (although it can be greatly improved) so will take no further part in this comparison. The 1105 5500kV Motors for the 249+ are slightly smaller and lower kV than the other modern 2.5" quads and personally I find them more suitable for a light-ish 2.5 inch propeller. I also like the fact that I can get the bulk of the performance out of it on 3s unlike the skystars bolt that really needs a 4s, although it is nice that the option is available. Although the babyhawk r pro and leader 2.5 have electronics capable of managing 4s, their motors are too high in kV to be practical here.
For me the R249+ hits a nice balance on price, weight and power meaning it's not the fastest, lightest or most powerful but it is a good balance of these which makes for respectable battery life, good performance less noise during flight. In the end you'll probably be driven more on promotional prices than any specific features here and unless you are very passionate about something specific it would be hard to argue with that reasoning. I think the last word on this would be that the quality of Diatone, FullSpeed, and EMax are somewhat on par with the Skystars bolt somewhere behind. Same goes for availability of spare parts - Fullspeed, Diatone and Emax support their products well.
2019 GT R249+ Conclusion
Diatone have done a Diatone and released a very nice quad on paper but this time at a much more competitive price than the previous 2018 GTR90. The R249+ reviewed here shares the same electronics and motors as the 1.9 inch R239 and 2 inch R249 but the 1105 5500kV motors suit this size best rather than adding unneccessary weight with the smaller-propped versions. It's a very predictible flyer that is far from slow on 3s which I this is where the sweet spot is on this quad although you can run on 4s for more speed but also more weight.
Would I recommend it? Sure it's a good quad but no better or worse that the Leader 2.5 or Babyhawk R Pro. Diatone, Fullspeed and Emax all have a strong brushless micro pedigree and resultant support for these models so that is a wash too. Really it will come to price and that will change from time to time depending on promotions so at the prices listed above. For now, the Diatone GT R249+ and Leader 2.5 look to have the best offering and for me personally the Diatone edges the Fullspeed Leader 2.5 with a faster F4 processor and motors that better suit my flying style. See my leader 2.5 review here to compare. For me the Babyhawk R pro is just too expensive AND heavy.
The Diatone GT 90 (Rabbit) R249+ is available from Banggood here as a plug and fly model
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T-mount propellers are those that are based on a 1.5mm diameter centre shaft secured by a 2mm screw either side. They have been the only mounting option for 2-2.5 inch props but are now becoming more popular for 3" due to the weight they save over a 5mm single shaft prop mount. There are only 4 different types of t-mount 3" prop currently available so I've compared them all plus the new HQ 2 blade which is due for imminent release plus a darkhorse prop in a smaller size to make up the numbers. Please note this is a subjective comparison based on my opinion but my help as a startpoint for your decision. This is based on real world feel, light time and bitter experience with motors I've burnt out.
Emax Avan 3 inch tri-blade
This is the first modern design 3 inch prop designed for a t-mount which was released with the 3" Babyhawk R (reviewed here).
HQ 3x3x3 v1s tri-blade
HQ props have the newest 3" t-mount prop design at present. This has been chosen as the stock propeller for the Full Speed Leader 3 (initial review here and flights here)
Gemfan 3035 triblade
This is quite an old prop and can be hard to find but is still suprisingly relevant.
Gemfan 3025 bi-blade
This is the original 3" t-mount prop and so can be found for sale in weird and wonderful places
HQ 3x3x2 v1s bi-blade
Just released at the time of writing: as per the 3x3x3 above but bi-blade rather than triblade. Disclaimer: I have not tested yet and below information based on assumptions from comparing bi-blades and tri-blades in general. Will update once mine arrive and I've tested.
Dark horse to consider...
Gemfan 2540 flash triblade
Yes this is a 2.5" prop but objectively it is so good it is worth considering downsizing. You can find an earlier review I did on these here and a review on the Skystars Bolt X120 which uses these on 4s here
Please note the King Kong 2840 propeller was not included here because I found the Gemfan 2540 superior in every way. Also I have not include the Rotor X 3044 because it is difficult to source where I am based. The feedback that I have had is that it is more aggressive in pitch than any of the above props and probably only suitable for for stator sizes 13xx and up.
Ever since I saw the first image of the first FlexRC Ascent I've been impressed. It is a simple micro quad frame that accepts 2" propellers, is super lightweight and has a cage that is designed around a micro CCD camera (runcam micro, foxeer micro, caddx micro, furibee micro etc.) This was one of the first frames designed around these superior cameras and in my opinion still one of the best.
Dmitry from FlexRC has since expanded on this winning formula and this has given birth to the 2.5" Ascent, 3" ascent desinged around the runcam split and most recently the Komori 3". The Komori is essentially based on the original 2" with a baseplate embiggened to take 3 inch props and extra torsion supports between front and rear arms to allow for minimal flex whilst stick with thin (but lightweight) baseplate. All up weight of the frame is 15g with included hardware. Shape is a squashed x - front and rear motors are closer together than left/right motors. *Theoretically* this should mean more stability but slower movement on roll and faster but less stable in pitch.
After spending a lot of time with the Leader 120, I was looking forward to a frame that better fits the micro CCD camera and can take a genuine 3" prop rather than 2.8".
For build components I essentially transferred my gear across from the Furibee X140 (review here) where I felt the heavy frame (although durable) was letting the performance down.
After initial flights I decided the 1306 weren't suitable - performance was dull on 3s albeit and improvement on the Furibee X140 owing to roughly 30g less weight in the frame. This is when I switched motors to the HGLRC Flame 1105 6000kV (reviewed here).
The build on this was really simple - FC/ESC/VTX were all bolted on to the baseplate as were the motors. I just love the way the side plates clip on with no fuss and still had plenty of room for the 3-layered stacks. Once in place itwas easy to add the 2 nylon standoff supplied which can be used place cable ties on as additional support for receiver and VTX antennas.
@s Betaflight setup
Since this is a custom setup I won't go into betaflight setting but to summarise I went with
I went into more detail on the performance of the motors here but overall 3s paired with these motors and overal setup was excellent. My Leader 120 on 3s was always very quick but was a tad unstable and highly strung. The Komori I felt fixed this feeling of instability - flight was a lot more predictable with linnear power and no twitching. What this translated to in reality was more enjoyable less stressful flight with no loss in top speed compared to the leader. 2s on this quad is ok - not as fast as the leader on 2s but I think some more agressive props like the Gemfan 3035 triblades would be better, This is primarily a 3s quad - I have no interest in 4s.
I've not yet put a lof of packs through but have already had a reasonable sideways landing on to rough chip tarseal. From this the carbon fibre that extends beyond the motors for production has had a slight delamination but nothing that affext performance. There is however a lot of material that extends beyond the motor meaning I could file back to removethe delaminated portion. It also means the motor was well protected in the crash - not a scratch on it.
It's no secret that I am a fan of light builds - going lighter means better agility and longer battery life as well as better resistance to crash due to less mass. The FlexRC Komori frame fits my desire for a 3 inch frame perfectly - super light with frame designed natively around a micro CCD camera. The komori does sacrifice a bit of durability for it's light weight but given I fly over grass mostly I'm happy to compromise a bit of durability for weight. Since the frame is light this then allowed me to choose lighter duty motors and batteries - which makes the entire build light. As well as the benefits above, lighter motors and batteries tend to be cheaper too.
Flight characteristics were excellent andI felt the combination of 3s 450mah - 1105 6000kV - Gemfan 3025 offered a well balanced combination of power, agility, stability and efficieny (i.e. longer flight times. I think my favourite Leader 120 has finally been bettered.