Introduction
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:

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.

4s
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.

FPV performance
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

If you liked this review or found it useful please consider clicking like or share on facebook via the links below. Links in this article help the retailers track my performance and allow me to continue these reviews and tutorials.

Correction
Firstly a very important correction. In the first review I showed a picture of the quadcopter minus battery sitting on a set of scales at 65g. I took this for granted and after measuring on my own scales got 84g. I don't usually trust weight in text but seeing it was sitting on digital scales I did not measure myself. Disappointing as this is misleading so I updated Gearbest immediately. To their credit they promptly took the image down and corrected the weight in the description - see below.

Preparing for flight
Just some minor housekeeping prior to the first flight. XM receiver was fixed in place on top of the VTX as it was dangling free when I received it. Antenna was fixed in place with a cable tie off the rear arm and heatshrink to secure. VTX antenna got the same treatment off the rear upper-deck of the frame. Lastly I replaced the rubbish battery strap with one from RJX hobbies (review here). Although a buckled strap was included as well as the one picture above, it was much too long? Weird.

Flight performance on 2s
Just because the Bolt X120 *can* fly on 2s doesn't mean you *should* fly on 2s. I used my Turnigy Nanotech 2s 950mah (47g) pack and needed about 40% throttle to hover. I could fly but performance was lacklustre and I got bored. I did get about 4 minutes flight time but won't say any more.

Flight performance on 3s
After my initial disappointment on the weight, performance on 3s 450mah turnigy nanotech was better than I had expected. It felt controlled with enough speed to be enjoyable. I had to switch to default betaflight 3.3 PIDs though since the customised PIDs look more like a 4s tune and felt sloppy as a result. I did manage to get good flight times on these little batteries of approximately 2.5 - 3.0 coming down at 3.75 volts and had fun doing so. Given then power of the quad I'd probably pefer a 650mah 3s for another minute or so of flight and would have less concern about sagging on big throttle punches. For the places I usually enjoy micros the most (tight with small trees) I found 3s the most fun.

Quick update: compared back to back on same batteries with my Leader 120 which is lighter (68g vs 84g) with 'smaller' motors (1104 7500kV vs. 1106 4500kV). I found it was similar speed with comparable handling and I actually got as good if not slightly better flight time on the Skystars Bolt - the extra stator size was negated by the lower kV from an efficiency standpoint. The leader however cannot do 4s...

4s Powah
When I went from 3s to 4s on the BabyHawk R 3" (review here) I got a reasonable increase in speed but not 33% as you'd probably expect. Given the same motor size (1106 4500kV) I was expecting something similar here but got a complete shock here - This thing ABSOLUTELY SCREAMS on 4s. I've always liked the Gemfan 2540 props (review here) but have never tried them on 4s and boy, they sure hold up and deliver on the extra power, it was like a different quad altogether. The speed was like nothing I'd felt on a micro and I had real trouble managing in a tight area. This probably wasn't helped by the fact I was using a CNHL Ministar 4s 650mah battery which weighs 87g so I was really blowing out on corners, even with a lot of extra throttle. It reminded my of running a heavy 4s 3 inch with 1408 motors - super fast but handled like a brick. I'd dare say 450mah 4s at around 62g would be a better option for weight control. at the cost of some flight time. As it stood I was getting 4 - 4.5 minutes on the 650mah battery. I've since moved to betaflight 3.4.0 and have got the tune tighter without oscillations but it is still a handful. For my piloting ability running this quad on 4s requires a bigger area akin to my 4 and 5 inch quads but that kind of deafeats the purpose of this micro. For my money and ability I actually prefer this on 3s - It is much quieter and handles better with the lower weight which is better suited to small parks. The noise alone on 4s makes people more wary of this one. 

Conclusion
Rather than trying to recommend how many cells you should run I've merely stated my opinions on what I want from a micro. The most important thing here is that this Skystars Bolt X120 is well and truly capable of comfortably running 3s or 4s depending on where you are flying or how you are feeling on a particular day. The new throttle limiting feature on betaflight is a great way of limiting power to fly on 4s if for example you want to stick with just this battery size with power more akin to 3s. I've written a full tutorial on this here including how to assign to an AUX switch.

Although I alluded to the similarities to the original Leader 120 (review here) it is clearly a different quadcopter with a different feel and different capabilities - it has a much better camera and VTX but is much heavier and designed to run on more cells which make it heavier again for a different flight feel. A better comparison is perhaps the BabyHawk R 3 inch which I find handles better but lacks the speed of this model, particularly on 4s. Images below on a scale for all of these for comparison.

The Skystars bolt can be bought exclusively from Gearbest in several different formats - an unbuilt kit with no receiver (PNF), a built quad with no receiver, or as a built quad with FRSKY or Flysky receivers.

Check on my discounts page regularly for specials but at the time of writing the unbuilt kit is available for $117 and the FRSKY BNF as seen here is available for $134

Since half of the planet is currently having weather that is forcing people indoors at the moment (not me haha!) I've reviewed some All In One (AIO) camera and VTX combos. Traditionally these have been used on tiny whoop style indoor brushed quads and smaller micro brushless quads although more and more brushless quads are using slightly heavier micro CCDs as standard.

Weight is still very much the name of the game in brushed quads as you'll struggle to get a 4:1 power to weight ratio even on the larger 8520-based brushed micros. This means CMOS-based AIO cameras are still the norm because they are so light. In this round up I've gone for some of the lightest cameras I can find and best of all, 2 include video in / video out so that no tricky wiring hacks are needed to run betaflight OSD.

Note: This is clearly not an exhaustive test, I happened to have a number of AIO camera at the same time I ordered for various micros so had a chance to compare. I though the improvements over the Eachine TX01 were impressive so thought it would be work sharing.

​The Contenders:

Results
Clearly discussion on image quality is missing here - I found the 4 CMOS AIO camera above very similar and wouldn't be able to tell apart in a blind test. The only AIO I've picked up which is clearly inferior is the VM2751 standard on the leader which is not included in this shootout. I thought this camera/vtx was the weak point of the Leader 120 quadcopter.

Recommendation
For a micro brushed quad without an OSD I'd recommend the LST S2. For goodness sakes it is only $9!!! Further to that it is light, easy to change channel / band / video format and small.

For a micro brushed quad with OSD or if you are after every milligram of weight savings, get the CM275T. It is CRAZY light at 3.2g and has a very convinient video/in out so that you don't need to mod your cam just to enjoy betaflight OSD - assuming your FC supports it. I know it's at odds with what I said about brushless and ccd cameras but this will be going on my Eyas X2 rebuild going for the lightest 2" possible - targetng 35g with props. Here is my original X2 eyas build on rotorbuilds if your curious.

For a brushless quad 2s and up just get the micro swift or equivalent and the TX200 VTX. The video quality is just so superior in all but the best lighting conditions. VTX can be a little tricky with band / channel display but transmission quality is excellent and you have the ability to bump the transmission power up to 200mW.

When I first jumped in to FPV quadcopters in March 2017, box goggles were all that fitted into my budget and at the time the Quanam Cyclops V2 from HobbyKing was one of the better models going. I've really enjoyed my time with these - an immersive 5 inch screen, useful OSD and pretty good reception for a non-diversity receiver. The only downside for me in practicality was the large size that was difficult to stuff into a backpack and to a lesser extent the reception for short-mid range flight. Looking dorky doesn't really matter to me, I have kids so a large set of box goggles doesn't even register on the shame scale.

Naturally I was therefore hesitant with the Aomway Commander V1, even with the glowing reviews around. The hesitation was short lived though. After speding sometime to figure out the menu options I found the field of view to be good, even after transferring from the quanam goggles which have some of the biggest fields of view on the market. The most important measure for me was that I could fly just as well (no worse anyway!) than with the box goggles - a completely different experience from the EV100 goggles.

By now, these goggles have been well reviewed but I'll cover of the points that were important to me as succinctly as possible:

• DVR is simple but works well. UI could have been more simple but took only a day or two till I was using confidently. Micro SDHC very easy to access
• Balance lead to 5.5mm adapter is super useful. Doesn't ship with a battery but using the balance lead from any 2s, 3s or 4s you can power these.
• Diversity it great, stock RHCP antenna is great, stock patch antenna sucks balls. I am yet to choose between a menace or TBS patch and based on video I've seen should not leave me wanting for a replacement receiver module.
• Light and comfortable to wear - better than the box goggles but I tend not to focus on this when flying anyway.
• Stock case looks nice but is too small! Lucky for me I can sneak them in my Taranix Q-x7s case. They are nice and small and take very little room.

Overall I'm pleased with the Amoway Commander V1 and these are a good model to get if you are coming from box goggles. In all honesty though I would not have been unhappy sticking with my box gogges but think in the longer run the Aomway Commander V1 will prove to be an upgrade that will grow on me. I'll definitely hang on to my trusty quanam cyclops V2 for my 5 year old to ride along with me.

Thanks to Gearbest for providing the sample for me to review and use. A link for the most up to date (revision 2) of the Aomway Commander V1 goggle is below, currently available for around $300. Check out my coupons and discounts for the latest flash sale or coupon for these.

https://www.gearbest.com/fpv-system/pp_602969.html