CTW Mini 105 - Just another FPV quad with 8520 motors? (review, work in progress) - RC Groups
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Mar 19, 2017, 05:12 AM
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Mini-Review

CTW Mini 105 - Just another FPV quad with 8520 motors? (review, work in progress)


So many 8mm brushed motor FPV quadcopters these days, that it seems like there is little to add, to the growing list of models and submodels. Along comes this CTW Mini 105, just another one, very similar to the other offerings? Well, actually, this one comes with a few surprises. Whether pleasant ones or not so, will be revealed soon, I think, as I have the quadcopter here, as we speak... (or better, type )



Disclaimer: I don't get paid, or in any other way make money with reviews like these. Product specifications and quality may vary at the manufacturer's discretion, and are beyond my influence. I cannot guarantee you will get a product that performs exactly the same as seen and described in this review. There is always room for a general discussion on the reviewed item, feel free to comment, but if you are planning to add a long review, instead of some summarizing remarks, it would be appreciated to put these in a new review topic or on your RCG blog page. And please, no affiliate links!

Note: When clicking a link that is posted in this review, some text or numbers might be added to the link, making it appear to be an affiliate link. However, all links I post in the review are clean, and this addition is done automatically by your browser and forum software, so sadly beyond my influence. If you don’t want this to happen, copy the link, then paste in an address line of a fresh browser window/tab.



For easy navigation, here's a list of contents:

1: Specifications (posting #1)
2: Unboxing (posting #1)
3: Transmitter/Preparing for 1st Flight (posting #1)
4: Flying Performance (posting #1)
5: Preliminary Verdict (posting #1)
6: Suitable for a Beginner? (posting #1)
7: Camera & FPV Performance (posting #2)
8: Additional Tuning, Modifications & Other Info (posting #2)
9: Suggestions for Improvements (posting #2)




1 - Specifications:


First, let's start with a link and a picture,



http://www.gearbest.com/micro-brushe...pp_609545.html




2 - Unboxing:


The Mini 105 comes in a thin, bland looking, cardboard box:




The label mentions it's the black version, which makes me wonder if there are ither color versions. Usually CF doesn't come in all kinds of shades and colors, so it might just be of very little info.

Anyway, inside we find a single foam insert, holding the quad, and the accessories:




The contents are, besides the quadcopter itself, a battery, as well as a USB charger, and a bag containing 8 props and self adhesive velcro to attach the battery:




Here is the quad alone, you can see the battery wire and receiver antenna sticking out the back. The receiver is not fixed yet, though it is already wired up. There is double face tape attached to the receiver, but the protective sheet is still on one side. This allows the receiver to slide out a little, so the owner can press the bind button. The sides are protected with a small CF plate, with a small opening to allow access to the USB port on the left side:






The bottom of the quad also shows a very clean design. Nice and flat, so the self adhesive velcro should be able to stick well. The motors are covered by semi-transparant rubber/silicone sleeves, that help protect the wires from impact, and also provided anti-slip and a cushion for landing:




On the top of the quad, it's also very clean looking, just the 2 buttons to adjust the FPV frequency, and invert the image:




The battery is a 1S 400mAh, weighing about 9.2g. This battery seems a little small for powering four 8520 motors.






3 – Transmitter/Preparing for 1st Flight:


Before mounting the props, the receiver was bound to the transmitter. There are no instructions, but using your intuition can get you far. I used a free memory spot set to D8, then powered on the quad while pressing the bind button on the receiver. Then activated bind on the Taranis, and the led on the receiver responded.

After that, I wanted to connect the quad to Cleanflight, but while Windows would install a driver for the board, when the cable was inserted, the com port number didn't change when connecting to Cleanflight app. Even re-installing the driver didn't help...

Checking on the Gearbest product page, I discovered a link to a firmware tool: http://download.appinthestore.com.s3...20Firmware.zip

It's a 20-something MB download, and once unzipped, contains a custom configuration, that is needed to connect the Mini 105 to the computer. This tool provides basic functions, like gyro calibration, but also calibrating the RX range of the board to the sticks of the transmitter. It's also possible to adjust ESC protocol (even OneShot 125, which doesn't apply to brushed ESCs anyway), as well as rates, which are called "Parameters" and also PID tuning, under the "Gains" tab:






Takes a little getting used to, as the interface is very unlike Clean/Beta-Flight, but it gets the job done, and the transmitter sticks calibration routine is very convenient too, no need to adjust stick travel on the transmitter, or mess with RX Range settings in the CLI. Would I prefer this over CleanFlight? No, probably not. But the setup wizard for the sticks, might be something that could be a nice addition to our better known configurator programs.

The flight mode settings seem to be limited to 3 choices, Atti (aka Angle Mode), Rate (Acro) and Ratti (aka Horizon Mode) as third option. The weird thing is that Rate is the middle choice, so if you want to go from Angle to Horizon, you will set the quad in rate first, before it goes on to the next choice. More logical would have been to put Rate as final choice. Good thing though, it's possible to use the software tool to reverse the channel that selects the flight modes, so you can either have Rate available for your default switch position, or Angle.

Arming is switch only, and you can't set the threshold, so for a 3 pos switch, it needs to be fully up or down to arm, the middle position won't do. I've used the top left switch on my Taranis, as that's the only 2 pos switch available. When armed, 2 red leds at the rear of the FC board, light up. These leds also work as tail leds, and reacting to certain stick movements, or LVC condition. Pretty neat actually, despite looking rather simple, and not using a very popular FC firmware, all basic features are present, and some extras here and there as well, as bonus feature.




4 - Flying Performance:


The first flight showed a little angle mode drift, but not progressive, but steady. So maybe the gyro calibration didn't go well enough. Connected the quad again, and this time after performing the calibration, the hover was steady enough. Control and throttle response were good, but not spectacular. The default rates are definitely geared towards smooth and slower flying, though personally I think a slow yaw rate might get people into trouble even sooner, because the natural response is to turn away, but that takes more time with a lower yaw speed. I'll include a screenshot of the default rates ("Parameters") soon. But anyway, first impression, not bad, not bad at all...

For the second flight, the rates were changed, more max angle, better yaw speed and faster pitch/roll. This was more like it. Flying around in the living room, the quad was more responsive, but still very smooth. Yaw speed could be a little faster still, but for a first outdoor flight, it will probably do.


Update 22 march 2017:

Yesterday I was able to do some outdoor testing. It was a bit windy, but judging by the control response when flying indoor, I thought it would handle it well. However, the current tuning/flight controller isn't very fit for handling a breeze. Hover is still solid, but when moving around, there is a tendency to start porpoising, and holding a steady altitude is tricky.

CTW Mini 105 - First outdoor test flight (1 min 1 sec)


I hope it's a matter of better tuning, as so far this quad has made a very solid impression upon me, but to be of much use around here, it needs to be able to handle some wind, or be condemned to flying on the very few windless days we have here. It's not very suitable for indoor FPV, since there is no prop protection.





5 - Preliminary Verdict:


The CTW Mini 105 may look like just another brushed FPV quadcopter, but it's fairly different actually. Apart from the very clean design, focusing on function instead of pure looks, it also offers a different, at times "software-wizard-style" interface to configure it's flight performance, while still providing access to key settings. It may not be as versatile and open source as Cleanflight or Betaflight, but some may prefer this different interface.


Pros:

- Clean and solid design
- 8 props included
- Motor and wiring well protected
- Good access to USB port
- Indicator leds at the rear
- Buzzer
- Once installed, the configurator tool is rather easy to get the quad ready for take off, or change settings like rates, etc.


Cons:

- Small battery
- No manual
- Fixed horizontal camera angle
- Custom FC firmware and configurator are not as versatile as other, more popular interfaces




6 - Suitable for a beginner?




(to be continued)
Last edited by SoloProFan; Mar 22, 2017 at 05:36 AM.
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Mar 19, 2017, 05:13 AM
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7 - Camera & FPV Performance:



8 Additional Tuning, Modifications & Other Info



9 Suggestions for Improvements:
Last edited by SoloProFan; Mar 19, 2017 at 08:20 AM.
Mar 19, 2017, 05:14 AM
Registered User
SeByDocKy's Avatar
It's official You have all the machines No more complains now
Latest blog entry: Youbi XV-130 130MM FPV Racer
Mar 19, 2017, 07:36 AM
Fan of just about anything RC
SoloProFan's Avatar
Quote:
Originally Posted by SeByDocKy
It's official You have all the machines No more complains now

No time to complain, too busy testing, but I don't have all. Lots of stuff between 68 and 120 that is available right now, or already on it's way to some reviewers. E90-X, KingKong 90GT, Furibee F36S, FX90, etc, etc...

Btw, this Mini 105 has some surprises, for instance, it doesn't use Clean/Beta-Flight at all. Just added lots of content to "unboxing" and "getting ready to fly" chapters
Mar 22, 2017, 05:38 AM
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Added a first flight video. Seems like it has trouble handling a breeze. Hopefully this is a matter of tuning.

Btw, the way the settings are laid out, I am beginning to suspect this quad might be running a (modified) version of OpenPilot or LibrePilot. Especially the way the PID page looks, resembles the "inner loop" and "outer loop" settings.
Sep 14, 2017, 03:58 PM
Registered User
Is the receiver replaceable? The frysky is only $28 now and i have extra flysky lying around (i only have a flysky transmitter)
Sep 14, 2017, 06:34 PM
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Quote:
Originally Posted by androidgamer
Is the receiver replaceable? The frysky is only $28 now and i have extra flysky lying around (i only have a flysky transmitter)

Yes, it uses a seperate receiver.
Oct 16, 2017, 10:16 PM
Registered User
beautiful write up! Helps alot esp. this drone didn't come with its own manual. Just got mine today, after i followed your instructions, i decided to calibrate my controller as well on the GUI. During calibration, all my stick/switch inputs show on the screen but as soon as i hit complete, all the sudden the throttle is not responding. I thought it might be a safety thing. so I disconnect from pc and hook up the battery and bind again, but the motors wont turn. I made sure that i had arm and disarm switch configured as well. I tried all the possible test i can do to single out the problem.

I bought the dsmx/dsm2 config. with my devo 7e i bound on both DSM(x/2) to test and still nothing. also throttle light on FC dose not turn on to indicate anything is going on. i get power to all accessories (vtx and receive) as well. I tried using a different devo 7e from my friend and still nothing.

I really dont know if its just broken or i set it up wrong.
Oct 17, 2017, 01:39 AM
Registered User
Also yesterday i got this product and i have similar problems, i can not bind it with taranis qx7.
In the box, there are no instructions, on the internet residual information. Tragedy.
Oct 17, 2017, 03:25 AM
Fan of just about anything RC
SoloProFan's Avatar
The FrSky receiver is inside the frame, and a bind button should be visible. I can check on mine, I still have it. I wonder if the FC is compatible with CleanFlight, or even Beta. The custom firmware might be intended to make things easier, but with limited info, this strategy backfires...


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