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Apr 09, 2014, 11:21 AM
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Mini-Review

XinXun X39 SKYKING




Introduction

In March 2014, XinXun announced four new models of quadcopter all "6-axis" stabilized: the X28, the X33, the X39 and the X40 all of them controled by a 2.4G controler. For each model, a "V" version is also available including a 0.3MP camera.
This review is dedicaced to the X39, a 250 size quadcopter copying the "AR-drone 2" design equiped of 8mnx20mn brushed motors.



Box content







+ 1 X39 quadcopter
+ 1 2.4G Remote control (Modified "SkyWakker" protocol with inverted RUD)
+ 1 1S 3.7V Lipo, 650mah (no discharge information)
+ 1 charger (via USB plug)
+ 1 instruction manual

Overview

This quad copy the design of the "ARDrone 2" by including a large EPS foam bodyguard/canopy surrounding props and main central electronical circuit, ideal for beginners.



The size of this X39 is a square of 32.5cmx32.5cm with a total height of 6.5cm. Without this bodyguard, the main frame dimensions are the same than WLtoys V212 for example, a 250mn size.
This quad is shipped with a 3.7V 1S 650mah lipo (no discharge information given) using a JST connector and scaling 18.7g.

[URL=http://www.hostingpics.net/viewer.php?id=456267DSCF3211.jpg]



The total weight including the battery is 125g (106.3g without battery).





The canopy is fixed with the 4 screws under the thin plastic cover to the main frame. The visible screws from the bottom part are used to fix shafts to the main frame.
A hole with a 3 pins connector is present probably to plug the camera for the X39V version.



The canopy weighs 28.6g and on the top of it, in the central of the main axis, a plastic decoration glued directlion of the EPS.



The solitidity of this bodyguard seems to be adapted for the multiple potential/occuring crashs protecting blades and main electronic part. One unique and small Led light is glued in the front part of the canopy which prevent to use the X39 for night flying.



Without canopy and battery, the X30 weighs 74.6g.



The main frame plastic is more solid and large than the V212 frame.
The battery bay is narrow but allow to insert a nanotech 750mah (18.4g) as battery replacement (change the micro-losi to a JST connector).



The carbon shafts/arms are 5mn and by consequence much more robust compared to the V212/V222 (3mn).
Motor pod feet are also more higher than V212 ones (+1cm) offering more free room to install a camera under the body.






Motors are coreless 8.5mnx20mn with a 11 teeth plastic pinion installed.







Unfortunatly, some 3mn(inner diameter)x6mn(outer diameter)x2mn oil bearings have been installed instead of real ball bearings.





The good news, there are exactly the same size as for the V959/V969/V212/V222.




If you buy the X39, I strongly recommend to install such ball bearings avoiding extra friction and protecting both motors and MOSFET. If spare parts are not immediatly available, you can install some V212 motors as replacement.
The main board have the famous MPU6050 as flight controller offering a 3+3axis for stabilization.



I was unable to read the reference of the main core unit, but I am strongly suspecting that the MCU is a Mini54ZAN.



The radio RF chip is hidden by sillicon paste, but the good news, I was able to bind the X39 with the "Sky Walker" protocol of deviationTX. To fly with my devo, I had to invert the RUD channel. It means that the RF chip is nRF24L01 compatible, probably a BK2423.
On bad point (compared to V212/V222 for example) is concerning the motor connexion to the main board. No connectors are installed, wires are directly soldered on the board. It means that you will need some basic soldering skills to replace a motor.
MOSFET are referenced by "2310" handling up to 4A. Some potential leds pins are visible on the board. It can be useful, if you plan to add extra leds for night flyng. Propollers are shorter but larger at extrimity than V212 model (V212 on right).




The TX is basic model: cheapy plastic, no LCD, fake antenna and based on the JXD 385/388 TX frame.







Trimming must be performed with sound, i.e. a long beep indicates the central position. Luckily, the X39 don't really need special trimming, vertical hovering is stable without shifting. Gimbals are rudimentary with more resistance close to the central position.



A 3 position switch allows to choose between beginner mode (30%), intermediate mode (60%) and sport mode (100%). Notice that in 100% mode, you have automatic flipping when sticks reach extreme positions. For me, it's representing a drawback especially when a flipping button is installed at the right shoulder position. Luckily, the X39 can be controlled via DeviationTX. In this case, you will enjoy full speed forward without automatic flipping. The antenna is trimmed to 28mn (shorter than theoritical 31mn for a perfect conductor). This latter should be fixed vertically for a better radio link.






First Flight !!!!

For the first flight, I used directly my devo 7E using the Sky Walker protocol. As you will see in the video, the yaw rate is very slow. I checked later with the original TX and the yaw rate is at least twice faster. So it's a bug in the actual deviationTX implementation. Whatever, with the canopy on, you have the feeling that the X39 is floating in the air. The forward speed is slow but the the quadcopter is very stable. Beginners will be able to anticipate any crash easely

The radio link is good (I fixed vertically RX antenna), I managed to control the quad up to 100m without any dropouts. Even with the canopy, the X39 got fast elevation capacity.

EDIT

XinXun X39 outdoors flight (3 min 19 sec)


Second flight

I tested it canopy off and it's clearly a different story. Much more powerful quad and much more faster. Without sacrifying flying duration too much, I am estimating payload capacity to 35-40g, ideal for a small FPV setup.
I also noticed a major drawback. After a light crash, I noticed some extra friction on the rear right gear setup. I couldn't clearly identify if it was due to a bended shaft or a bended motor axis. I managed to partially solved the problem by dissambling this part.

Fifth flight, I flew it indoors but I didn't pay attention that front left motor had also some extra friction. The associated MOSFET burnt and by consequence my X39 is grounded. I Hope to fix it asap by soldering a new equivalent MOSFET.


Conclusions

I appreciated this quad and for me is more dedicaced for beginners who want a microquad for practicing outdoors and robust to multiple crashes (thanks to the EPS foam canopy). The radio link is solid and seems to not suffer from any dropout. Without canopy, this quad have good potential for FPV (probably due to good props design). By the way, I am regretting the absence of real ball bearings, motor connectors for an easier mantenance. I am also regretting the automatic flipping choice at 100% rate and some potential friction in the gear setup.



PROS

+ Stable and crash resistant quad, a good choice for beginners who want to practice outdoors
+ Nice look with canopy on
+ Good flying duration capacity (up to 8mn foamless)
+ Good lift capacity (payload of approximatively 40g foamless with respect to 5-6mn of flight duration)
+ Silent even with canopy on
+ Good radio link without observed dropout
+ DeviationTX compatible


CONS

- No ball bearings but brass bushings
- No motor connectors (maintenance more difficult)
- RX antenna should be fixed vertically (need to remove canopy to fix it)
- Cheapy TX plastic
- Potential friction between gear wheel and motor pinion
- 60 55.6 USD (versus 65 USD for a V212 with LCD display, ball-bearing, and connectors)


XinXun X39 unboxing (Courtesy of Tmart) (5 min 34 sec)



This quadcopter have been courtesy provided by Tmart in order to make a fair and not biased review. I would like to thanks them for this attitude.

X39

http://www.tmart.com/XinXun-X39-4-Ch...d_p242253.html

X39V

http://www.tmart.com/XinXun-X39V-4-C...w_p242260.html


LiPo subtitution :

1S 3.7V 750mah, 35C-70C nanotech (need to solder JST connector)

EDIT




EDIT 04/10/14

Price decreased a bit to 56 USD
Last edited by SeByDocKy; Aug 15, 2014 at 12:50 AM.
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Apr 09, 2014, 11:22 AM
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Reserved for mods and videos
Apr 09, 2014, 12:26 PM
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650mah, not 6500mah. ...although, that would be epic!
Nice write-up brother.


"Oil Bearings" more commonly known as "Brass Bushings"

Apr 09, 2014, 12:28 PM
Registered User
That battery is heavy at 18+ grams. My NanoTechs are 15.9-16.3g.
Apr 09, 2014, 12:30 PM
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Quote:
Originally Posted by EhnTeePee View Post
650mah, not 6500mah. ...although, that would be epic!
Nice write-up brother.


Yeah sorry I will correct (billions of ) typos. Thanks
Apr 09, 2014, 12:31 PM
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Quote:
Originally Posted by EhnTeePee View Post
That battery is heavy at 18+ grams. My NanoTechs are 15.9-16.3g.

It's true, I add a photo of my 750 nanotech...
Apr 09, 2014, 12:35 PM
Registered User
Sweet bro'
Looking forward to seeing more of it in flight.

I was speaking of the stock battery at 18+g

I use the NT 600's and love them for their power, weight and flight times.
Thanks again SBD
Apr 09, 2014, 01:17 PM
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SeByDocKy's Avatar
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Quote:
Originally Posted by EhnTeePee View Post
Sweet bro'
Looking forward to seeing more of it in flight.

I was speaking of the stock battery at 18+g

I use the NT 600's and love them for their power, weight and flight times.
Thanks again SBD
Actually, my X39 is grounded, hope to repair it on friday.

If you have some link for your LiPo, I will add it
Apr 09, 2014, 01:37 PM
Registered User
Turnigy NanoTech 600mah
It's obviously the one we use for most of the vxxx series of quads.
I have been very happy with them for their light weight, power and flight times.
I get 13 minutes before lvc in my v222 with 65+ flights on it.
No landing gear, canopy etc. AUW is 89.0g



Just read that you had a grounding, sorry brother. ..surely, some WLToys Vxxx motors will do.
Apr 09, 2014, 01:50 PM
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Thread OP
Quote:
Originally Posted by EhnTeePee View Post
Turnigy NanoTech 600mah
It's obviously the one we use for most of the vxxx series of quads.
I have been very happy with them for their light weight, power and flight times.
I get 13 minutes before lvc in my v222 with 65+ flights on it.
No landing gear, canopy etc. AUW is 89.0g



Just read that you had a grounding, sorry brother. ..surely, some WLToys Vxxx motors will do.

13 mn ... it's a lot.... Your AUW is very low...

Unfortunatly, a tiny MOSFET burnt ....
Apr 10, 2014, 01:46 AM
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Price dropped a bit to 55.6 USD
Apr 25, 2014, 04:53 PM
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Camera or Compatible Camera Part


I bought this quad while in Shanghai, China for around 50$ and was shown the quad with camera but upon making it home in the states noticed they actually gave me the model without the camera. Do you know of a compatible camera that'll work with it and maybe a link to purchase? {XinXun X39 4 Channel 2.4G RC Quadcopter (Mode 2) RTF Red}
Apr 26, 2014, 12:58 AM
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Quote:
Originally Posted by momulah View Post
I bought this quad while in Shanghai, China for around 50$ and was shown the quad with camera but upon making it home in the states noticed they actually gave me the model without the camera. Do you know of a compatible camera that'll work with it and maybe a link to purchase? {XinXun X39 4 Channel 2.4G RC Quadcopter (Mode 2) RTF Red}
Well, the spare parts are not available (hope it will be). Maybe a WLtoys V222 camera would be compatible (must share the same 3 pins connector). By the way, usually, provided camera with such toyquad are not fantastic. Keep your money for a 808#16 V3 lens D or a mobius camera instead.
Jun 01, 2014, 11:49 AM
Registered User
Hi, How are we going to control the video recording? Which button are pressed?
Jun 01, 2014, 02:07 PM
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Quote:
Originally Posted by ziya3400 View Post
Hi, How are we going to control the video recording? Which button are pressed?
I don't have the video version, but I guess you can turn on/off video by pressing left shoulder button


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