The Diatone GT-M3 is a 3″ Micro Quad in a stretch X frame. It’s a PNP model which means it comes pre-built pretty much with everything you need but a radio receiver. In this review we will take a close look and I will show you how to set it up and how it performs in the air.
Buy the Diatone GT-M3 PNP Racing Drone from:
The Stretch X is designed for racing while the Normal X is designed for freestyle as discussed in our mini quad frame buyer’s guide. But I don’t see why you should be restricted by these configurations :)
- Frame Size: 143mm, fits 3″ propellers maximum
- F4 Flight Controller
- MPU6000, allows 8K/8K Looptime
- Betaflight OSD
- 16M Flash Memory for Blackbox
- 5V BEC
- Current Sensor
- Camera: Runcam Micro Swift 1
- VTX: TBS Unify Pro
- ESC: BLHeli_S 25A ESC Dshot600
- Motor: Edge racing 1408 4000KV
- Supports 3S and 4S LiPo
Really good spec and all top notch brand name components :)
I like how the GT-M3 is shipped with prop nuts of all different colours. The build quality is just excellent and the design is very well thought out.
Diatone’s recent pre-built models are all shipped with TBS Unify Pro video transmitters. They could probably have saved $20-$30 by using a generic VTX just like they’ve done with the FPV camera, but I appreciate having a brand name VTX on the model. Having all the latest and greatest components onboard makes it one of the most premium micro models on the market.
They designed a PCB board to house the VTX which contains what seems to be a power filtering system for clean video. All the capacitors are well protected by the frame and nothing is sticking out.
The arms are 3mm thick and replaceable, sandwiched by two 1mm plates. This makes a super stiff frame. Carbon fibre looks to be of good quality.
The countersunk screws on the bottom plate are such great touch in the design. This prevents batteries getting puncture from screw head when landing or crashing.
I really like the frame design, if you wish to build one with your own electronics, you can get the frame separately here:
Diatone decided to use 20AWG wires for the X30 pigtail, which I would consider small for the 1344W rated power, with a peak power of 1548W. For 4S that’s roughly 80A to 90A!
I guess they are trying to make this quad as light weight as possible, by using the smallest possible wires for this build in the cost of higher resistance and power loss. That shouldn’t bee too big of a problem if we don’t draw that kind of power constantly.
In my testing with 4S batteries, the quad draw no more than 30A in high speed cruising, and no more than 60A in punch outs. Not quite close to the rated power, but at least we know it should be a problem for the thin wires.
Installing the Radio Receiver (RX)
I like the Diatone GT frame design, you only need to remove 2 screws to access the FC stack by lifting the cage up.
Here is the connection between FC and R-XSR. I am using TX6 (UART6) for SmartPort. Because it’s an F4 flight controller without built-in inverter, I am using the “uninverted” Smartport signal. Or you can use soft serial to handle the original “inverted signal” if you want.
I installed the receiver on top of the VTX with some foam tape. The antennas are fixed to the rear arms with zip ties and heatshrink.
A bit Heavy?
The GT-M3 weighs 142g without battery which is pretty heavy for a 3″ quad. The frame might look a bit “bulky” but it’s actually pretty light weight at only 21g.
The main weight contributor is the 1408 motors which weigh 19g each. Most 2.5″ or 3″ builds these days run 1106 or 1108 motors that are around the 8 to 10 grams mark, which makes a 40g weight difference between these builds.
For this reason you really have to use 4S to bring out the power in these motors. 3S is fine too if you just want to cruise.
I am using 4S 1000mAh LiPo with it, 800mAh would also do nicely. Make sure the batteries come with XT30 connector though.
Setting up in Betaflight
The quad ships with Betaflight V3.2.2, so I decided to update Betaflight firmware first to the latest V3.3. If you are not familiar with Betaflight you can skip the update and just set it up to fly. Here are the settings I used in Betaflight.
- 8K/8K (Gyro Sampling, Looptime)
- Setpoint Weight: 0.95, Transition: 0.2
- I just left PID at default for now, will come back when I have come up with a better tune
Testing, Flying and Final Thoughts
Quite a few people complained about the motor bearing wearing out quickly on 4S. I’ve only flown the quad for a few batteries so it’s still too early for me to comment on durability. But I will come back and update if i have any issues with it.
To be honest, the design of the GT-M3 is close to impeccable. Diatone has gone through at least 3 iterations of the GT series to find a recipe that works. The parts are solid and have excellent quality, you do get what you pay for.
The GT-M3 flies very much like a 5″, perhaps not as fast, but it’s very snappy and has great acceleration. Perfect for indoor racing, and outdoor acro flying. It’s quieter and less intimidating than a 5″ mini quad to fly in a busy park :)
And yes, so far I am very happy with the GT-M3 and I do recommend it.