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.
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.