Racerstar BR2307S 2500KV review

Edit: I have flown these today 12.11.2017, they are smooth and quiet, I have flown 7 packs and it they aren’t even getting warm after 3 minute flight in typical racing conditions with DAL 5046C props. They really open up and show full potential above 60-65% throttle. It seems that these motors have a lot of power and accelerate really fast.

Here is a test video with the first pack

Edit 2: I have been flying these with Dal Cyclone 5046 and I really like the torque they provide on low throttle, they seem to be more than able to work with heavier props. I have found this youtube review with thrust results https://www.youtube.com/watch?v=l3fxH… and they seem to pull 1400 grams and drawing around 40 amps on 5046C at max throttle.

You are getting what you have paid for. These motors are certainly a bargain for a cheaper builds and also as motors used for training without worrying if you destroy them. I have ordered these as soon as they were available for sale on BangGood. I was worried a bit since there were no reviews, but based on my previous experience with Racerstar motors, I have decided to bite the bullet and order them.


The Racerstar BR2307S 2500KV arrived in regular Racerstar motor paperbox packaging  protected in bubble wrap. There were no extras in the box except for a nylon bag with 4X M3x8 and 4X M3x6 motor screws.

It seems that Racerstar stopped the practice of offering CW and CCW motors and from now on they are only offering CW ones. Anyway in my experience,  the previous models as BR2306S the CCW ones had problems with the build quality.

Overall look and quality

These are very nice looking motors and they look exceptionally good when mounted on a miniquad. The overall build quality seems similar or a bit lower than the one on BR2306S, there are small dents on the bell edge, the anodizing of screw nuts seems like unfinished. Maybe this is due to the fact that this is first series of these motors but it is worth noting. It looks that these motors are painted instead of anodized. There are visible traces on the motor screw nut and at the motor bottom.

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One of the things that I have found to be improved is the bearing quality, all 4 motors have decent bearings and no vertical movement on the bell.
The magnets that are used in these motors look lake the ones used in BR2306S. They aren’t curved and the air gap has considerable height.
The windings seem to be machine filled with multi-strand wires.


The motor wires are 7cm long which is unfavorable for a builds with 4in1 ESCs where you should put some extra effort in extending the wires.



The motor weight is 37 grams with the wires, probably 34 grams with shorter wires on a normal build with 4 ESCs.

The height is 34mm and the width is 28.5mm

I have yet to test these, and I’m going to install them on one of my KISS builds tonight as soon as I finish this post. They should serve as a replacement for Emax RS2205 2300KV so on paper they should be a considerable improvement. I will update this post with my impressions.

You can buy these motors here



Pros and Cons

Pros: Cheap great looking motors, for budget builds or for race practice. No play in the bell and the bearings are smooth on all 4 motors that I have got.

Cons: Build quality seems similar or a bit lower then previous models. The motor seems painted and not anodized. The motors use C-clip. It would be great improvement to see the similar motors with a screw instead. There is considerable airgap between the magnets and the stator. They seem a bit heavy and the wire length is not suitable for 4in1 ESC builds

Moments from the photo session

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iFlight iX5 and Thor Loki carbon frames

Recently I have finished a build based on Omnibus F4 Pro and Racerstar 33A 4in1 ESCs. I have flown it three times and the FC stopped working so I had to replace it and since it was clone I have bought the original Omnibus from a friend. After that I have had some problems with ESC desyncs and I have managed to break my X-Foot frame, so instead of ordering another one, since I started to suspect that this will be a problematic build, I have started looking for affordable 200-210mm carbon frames with 4-5mm thick base plate.

After doing some research I have ordered one Loki V1 with 5mm base plate and one V2  with T700 carbon. The V1 one arrived sooner than the other so I have moved everything on this frame. These frames are versatile and could be used both for racing and freestyle. The battery can be placed on the bottom and on the top depending on your style of flying.

Loki V1

THOR210 Loki (nevermind the naming)

This frame costs $30 on Aliexpress. The baseplate is 5mm thick and the top plate is 2mm thick and the overall weight is around 90 grams with hardware.
I have read that some people complain that the carbon isn’t stiff enough and it bends on crashes and I can confirm that this is true, since I have managed to slightly bend one of the arms without breaking it. After that I was able to straighten it up and I have reinforced the arms side walls with super glue which made the arms stiffer.
Overall I’m satisfied with this frame but if I should decide between this one and the V2, I would get the V2

THOR V2 Loki

This is upgraded version of the V1, it costs around $36, it is a bit lighter,  82 grams it has titanium screws and it is made of T700 high quality carbon. The bottom plate has recessed bolt holes. The kit also includes camera side plates. I haven’t got my hands on this one, since I’m still waiting it to arrive, but I will update this post with my findings as soon as I got it.

Thor v2

iFlight iX5 V2

iFlight has been producing a high quality frames for a affordable price for quite a while now. They have several versions of the iX5 based on the build material: carbon fiber, carbon fiber composite and carbon and molding composite material. The overall frame geometry is similar to the Thor frames. The carbon fiber costs $35 and it weights 85 grams, the baseplate is made from 4mm carbon fiber and 2mm top plate. Be aware that this frame uses 28mm standoffs and some cameras may not fit in.

Carbon fiber iFlight iX5

When ordering from iFlight website you have the ability to choose and combine it with additional accessories.
Overall this is really high quality carbon frame that is widely used as a goto frame for cheaper builds. A lot of pilots are flying rigs based on this frame that are around 250 grams range.

The composite version – iFlight RACER iX5S costs $34 and it is based on composite material and 3K carbon sandwich. This combination provides a very light frame 66.7 grams and doesn’t sacrifice the overall toughness. The composite material seems to be balsa wood as stated in the product description.

Composite iFlight iX5

The molded composite material version – iFlight Ultimate iX5 costs $35 and is similar to the one above with one difference that the carbon fiber sheets are molded around the balsa instead of sandwiched

Molded iFlight iX5

Let me know your thoughts, what is your favorite carbon frame?

New RacerStar BR2406S 2300/2600KV and BR2307S 2200/2500KV Fire edition available on Banggood

If you are in for really cheap motors I’m sure that you are already familiar with RacerStar’s BR series which although have relatively low-quality components, they have established themselves as great motors for training and a must for every cheap build.

I have been flying BR2306S 2700KV on one of my rigs for quite a while and I think that they are great motors for the price, although two of them came with considerable play in the bearings that wasn’t affecting the flight characteristics. I have also managed to bend two axles in a hard crash on a concrete but for an $8 motor I have just replaced them and continued flying.

My rig with BR2306 2700 it is not the lightest build but I was happy with the result when I have put it together.


A few days ago RacerStar released two new types of motors BR2406 and BR2307  in the same price range. You will get 4X BR2406S for $36 and $X BR2307S for $35 on Banggood

RacerStar 2406 2600KV RacerStar 2307 2500KV

Here are some specs:

Item name: Fire Edition BR2406S 2600KV motor

RPM/V: 2600KV
Height: 33mm
Width: 29.6mm
Shaft diameter: M5
Motor mount hole size: M3
Screw thread: clockwise (CW)
Weight: 35 grams
Voltage: 2-4S
Battery: 2-4S lipo battery
Item name: Fire Edition BR2307S 2500KV motor

RPM/V: 2500KV
Height: 34mm
Width: 28.5mm
Shaft diameter: M5
Motor mount hole size: M3
Screw thread: clockwise (CW)
Weight: 36 grams
Voltage: 2-4S
Battery: 2-4S lipo battery

I have already ordered the BR2307S 2500KV and BR2406S 2600KV and I will be reviewing them as soon as have them.
At the moment there aren’t any reviews on these motors but I would expect either miniquadtestbench.com or EngineerX  to have them soon for a review.

They are not as durable as the pricier motors, but for the price, you could replace them much often. Plenty of times I hear people replacing the stock bearings with a high-quality  EZO, original NMB or even Fushi brand from AliExpress. This means that you will invest a bit more money in them and the overall price will get closer to AOKFLY or RCX motors.

It would be good for RacerStar to release spare parts for these motors soon so we could order some spare parts in the same order when ordering the motors.

Hobbywing XRotor Micro 40A 2-5S 4 in 1 BLHeli_S DShot600 Ready

Hobbywing is a long time player on the market of top-notch ESCs and finally, they have come up with a 4 in 1 40 amp DShot600 ready ESC with a current sensor and support for up to 5S voltage.


To be honest, if I had seen this ESC half year ago I would have been asking myself why 40A, but as the things are developing we may need batteries with double C rating then the ones that are already on the market, especially for motors like BrotherHobby Avenger


The build quality is up to the Hobbywing standards. They are using EMF8BB21F16G MCUs with the operating frequency of up to 48MHz. The motor soldering pads are neatly placed on the board and not protruding from the sides as on the Racerstar 4 in 1 ESCs which from other side means that you may need a bit longer motor wires compared to the other ESCs but I don’t think that may be a problem on builds that are up to 210mm. Sometimes even on them if you are unlucky enough you may have to extend the motor wires for motors like Racerstar BR2306S that are almost suitable on 210mm frame (one of the wires could reach the soldering pads, but you will have to extend the other two). There is a dedicated connector for Hobbywing XRotor Omnibus F4 Flight Controller which means far less soldering, you will have to solder the video in and video out wires for the OSD and the SBUS connection wires for your receiver. There is also dedicated type connector on the FC, probably for a VTX, but by the time I’m typing this post it is not out yet and it seems that they will be going the “cube” path too by offering all in one stack.


One thing to note that the ESC could only provide BEC output of 5V for up to 1.5A,  although there are 3.3V, 5.2V and 12V pads on the board they are only for voltage monitoring and they couldn’t provide the load capacity

Brand name: Hobbywing
Item name: XRotor 40A ESC
Cont./Peak Current: 40Ax4/50Ax4
Input Voltage: 2-5S Lipo
BEC output: 5V & 1.5A
Firmware: BLHeli_S A-H-50 16.5
Input Wires: Red-14AWG-130mm / Black-14AWG-130mm
Output Wires: No wires but solder tabs
Support: DShot150/300/600,  Oneshot125, Oneshot42
Size: 42.6x36x4mm
Weight: 10g

Racerstar TattooF4S 30A BLHELI_32 4in1 ESC 5V BEC w/ F4 Flight Controller AIO OSD BEC Current Sensor

Finally, the prayers of many fpv pilots were answered, Racerstar has come with an all in one solution that that incorporates F4 flight controller, 4 in 1 ESC with ‎BLHeli_32, OSD and current sensor – TattooF4S

Is is currently in preorder on BangGood and it sells for $75 which is almost equal to the price of buying decent F4 FC and 4 in 1 ESC.


This one seems a super solution for neat light builds and also a much better solution for having current sensor than the one on Omnibus boards.

One of my concerns is that it is rated only up to 30A so you should be careful with the choice of motors and props.

Here are some specs:
BLHELI_32 4in1 30A+F4+OSD
Con.current: 30A
Peak current(10s): 35A
Lipo: 2-4s
Programming: yes

Input: 2-4s lipo
Output voltage: 5V/2A
ICM-MPU6000 Accelerometers and Gyroscopes
MicroUSB socket
Weight: 22g
Size(PCB): 36*36mm

TattooF4S - What's in the package

Package inlcuded:
1* 30A 4in1 ESC built-in F4 flight controller
1* power cable
1* bag of screws


BLHeli_32 Dshot1200 side by side comparison of the ESCs available on Banggood

After watching Joshua’s video regarding BLHeli_32 I was intrigued to see if there are any available on Banggood and to my surprise, I have found that the bigger manufacturers like RacerStar, Favourite and DYS have already come up with their models based on BLHeli_32 with Dshot1200 support.


I have found 4 models, three of them are 35A and one is 33A. It seems that these are intended for the newer 2206 and 2207 motors that are power hungry.

These are the models that are available at the moment:

Update: The Racer33 is not running the official BLHeli_32 firmware and it is not updatable via the suite, so it is better to avoid this one.

Racerstar Racer33 33A
Con. current: 33A
Peak current(10S): 36A
Lipo: 2-4S
Programming: YES
Size(PCB): 27x15mm
Weight: 9.0g
Favourite FVT LittleBee 35A
Con. current: 35A,
Peak current(10s): 40A
Lipo: 2-4S Lipo
Programming: Yes
Size: 27*15mm.
Weight:8g (include Power and signal wire)
Racerstar TATTO 35A
Con. current: 35A
Peak current(10s): 43A
Lipo: 2-5S
Programming: Yes
Weight: 3g
Size (PCB): 27*16mm
DYS BLHeli_32bit 35A
Con. current: 35A
Lipo: 2-6S Lipo
Weight: 4.32g (without any cables)
Size: 32x15mm

BLHeli_32 is the third generation that runs on  ARM 32bit MCU initially Cortex-M0 running at 48MHz that could run input signals with lower latency at faster rates, you could find more info here.

The next logical step for the manufacturers would be to come up with some 4 in 1 BLHeli_32 ESCs since plenty of the pilots are using them in their super clean builds.



Emax RS2306 Black Edition 2750KV/2400KV

It seems that Emax is stepping up their game and jumped on the 23xx  bandwagon.
The RS2306 are the newest motors in their product line. They come in 2400KV and 2750KV and are designed for as stated by Emax.
These are available for pre-order here for a $22-$23 price depending on the shipping.

I haven’t yet met a pilot that hasn’t flown the redbottoms, whether that is the older ones 2300/2600 or the newer versions.

As stated by Emax, the RS2306 are designed to set a new standard of power and response for pilots seeking the ultimate in flight performance. With nearly twice the level of thrust of the original Red Bottom, the new RS2306 sets the bar even higher by pushing 2kg of thrust with 5045×3 propeller on 5S or 6045×3 on 4S.

The RS2306 are a continuation of the design that is used on the older RS2205-S.
Lighter bell, hollowed steel shaft, bigger bearings, lower profile, and kept the overall diameter just 0.4mm wider than RS2205-S!


Technical data:
Framework: 12N14P
No. of cells: 3-4S
Propeller: 5 inch
Diameter: 28.3MM
Length: 30.1MM

05197732-bea0-4742-b6d1-78e108c114a51.8mm N48SH Arc magnets (thinner and lighter which allow lower mass on the outer portion of the bell, resulting in faster acceleration. Less energy lost and more power delivered to the propeller).
BEEFY 4mm Hardened and Tempered Hollow Steel Shaft: Breaking shafts are a thing of the past.
0.15mm High Silicon-Steel Laminations: Higher volume of silicon increases electrical resistance in the lamination, reducing eddy-currents within the system (Translates electrical energy into mechanical energy more efficiently.).
High quality 4mm Inner diameter Steel Ball Bearings.

The 2400KV are stated to have 1552 grams of thrust and the 2750KV, 1762 grams on 4S. I’m not sure if I’m to believe these readouts, you could find more realistic data and review on the Miniquad test bench website

iCharger 106B+

iCharger R5 resistor replacement

Yesterday I was out flying and after I got back home I have started charging my batt packs, as usual, to have them ready for the next day.
I’m using my old and trusty iCharger 106B+ for charging for the past 3-4 years and haven’t had any problems with it, but not this time 🙂
Tha charger seemed to be working OK, it was displaying that the batteries were charging and the amount of mAh that were inputted but the battery voltage wasn’t changing and after I have stopped the charging process after an hour or so and measured the batteries I was certain that something is wrong with it since there was no change in the voltage.


After removing the cover I saw that one M-shaped electronic element was burned, and fortunately, it was marked on the board as R5 so I knew that it was some kind of resistor, but I haven’t seen this kind.
I have decided to contact a friend of mine Marjan that is an expert in this field and sent him some photos of the burned element. He said that it is a shunt resistor that is used for measuring the current and he also mentioned that these are very hard to find.

I have tried googling R5 and iCharger just to find that a lot of people have had a similar problem with several other iCharger models, but I wasn’t able to find any info regarding the mysterious R5 resistor. I have also tried contacting some of the shops that are selling iCharger equipment, but I haven’t got any response.

A bit disappointed that I would not be able to repair my charger I was getting ready to order some of the newer and also cheaper models like ISDT Q6 Plus 300W 14A or ISDT SC-608 150W 8A

Meanwhile, I was able to find one functional 106B+ so I could measure the R5 resistance but unfortunately, my multimeter wasn’t precise enough so I have measured something between 100 and 200 mΩ, closer to 100 and I have tried to find similar in the nearby electronics shop, but I wasn’t able to find shunt, just regular 5W 100mΩ ceramic ones, so I have called my friend again and he told be to drop by in his repair shop so we could try to replace she burned one with a ceramic and see if that will work.


After soldering the ceramic one the charger continued to misbehave and Marjan decided to try with 10mΩ, 200mΩ and several other resistors without any luck, lastly, he decided to try and make one from a steel spring wire. It was a lucky guess but it worked and the measurement was as precise as it was previously. For anyone having the same trouble here is a photo of the steel spring substitute shunt resistor


And the be more precise the measurements are the following:

Wire diameter: 1mm
Coil diameter:
The number of coils:
Coil to board distance: 7mm

Hope this helps everyone that have broken iCharger because of the R5 resistor, mine is perfectly normal now.

Eachine VR-007 Pro

Eachine VR-007 Pro

Eachine VR-007 are one of the cheapest video goggles with built-in video receiver for a price of $49.99 on BangGood currently under restocking. I have seen many of the pilots recommending them to the newcomers into the FPV miniquad racing/freestyle hobby or as the cheapest alternative to the Fatsharks or Skyzones for the pilots that are on a budget.

They are one of the goggles with the smallest form factor, decent video quality, and decent reception.

Today Eachine has announced the upgraded version VR-007 Pro that could be preordered for $39.99 here and it will arrive on 31st of March.

Eachine VR-007 Pro

Here is a short comparison of the VR-007 and VR-007 Pro:

VR-007 VR-007 Pro
Dimension (mm) 148 x 176 x 102 151 x 177 x 103
Weight, batt inc. 280 grams 241 grams
Screen size 4.3 inch 4.3 inch
Screen resolution 480×272 480×272
Battery 1600mah 7.4V 1600mah 3.7V
Battery weight 24 grams 24 grams
Current Consumption 500mA 350-450mA
Video receiver 40CH 5.8GHz 40CH 5.8GHz

So the main differences are that the pro version is a bit lighter (39 grams) and also it has increased size by 1-2 mm.
The Pro version uses 1S battery instead of the 2S on the regular one. It is a bit odd since both batteries have same weight but this seems to be copy-pasted info from the VR-007 product description.
It is also stated that the pro version has “Upgraded receiver, with Power Indicator and Frequency Display” but I will have to wait to get my hands on them to check what exactly this means.

Judging by the initial info that is provided and by the success of the VR-007 this should be a great deal for someone that is planning to purchase cheap goggles with decent quality and I would highly recommend them to any novice pilot.

Favourite FVT LittleBee Spring 10A×4 Blheli_S 2-3S ESC

Are 4 in 1 ESCs becoming mainstream?

After a week of posting my first look thoughts on Racerstar Star20 I can see that the manufacturers have already started to adopt the idea of 4 in 1 ESC and various products are popping out on websites like BangGood.

One thing that is interesting is that most of the manufacturers haven’t yet accepted the interchangeable feature that enables the end user to change any burned ESC with ease by swapping 1/4 of the board. At the moment only RacerStar and FPV Model (X-Racer) are offering such feature.

Here are some upcoming 4 in 1 ESC models, two of them are intended for the micro class and one for the mini:


Micro 20x20mm 20A 2-4S 4 In 1 BLHeli_S DSHOT600 ONESHOT FPV Racing Brushless ESC

Micro-20x20mm-20A-2-4S-4-In-1-BLHeli_S-DSHOT600-ONESHOT-FPV-Racing-Brushless-ESCThis model has the EFM8BB21F16G processor and runs on BLHeli_S firmware, works on a continuous current of 4 x 20A and burst current of 4 x 25A for 5 seconds. It has the new-generation 3-in-1 MOSFET driver and it supports up to 4S voltage. This is no BEC version that costs around $28


Favourite FVT LittleBee Spring 10A×4 Blheli_S 2-3S ESC Support Oneshot125 Oneshot42 Mutishot Dshot

Favourite FVT LittleBee Spring 10A×4 Blheli_S 2-3S ESCThis one is intended for the micro FPV quadcopter class. The fact that FVT has joined the 4 in 1 band just adds to the fact that we will be seeing more and more ESC like this in future. Intended for 2-3S voltage and continuous current of 10A, 15A max for 10 seconds, 20 x 20mm mounting holes. It weights 6g and supports Oneshot Mutishot and Dshot. Main IC: EFM8BB21F16F, MCU run 48MHz. The price of this one is around $34. There is also a 4 x 6A version available here


FLYTOWER F3 Spare Part 30A 2-4S BLHeli_S 4 In 1 ESC DSHOT Integrated PDB

94224381-14bf-4bf1-86e6-7602f56c945fThis one features integrated PDB and battery monitoring, it supports up to 4S voltage. Works on 4 x 30A continuous current and 4 X 35A max current for up to 10 seconds. It supports Dshot 600 and weights 10 grams. And all that will cost you around $39


Let me know if you know of any upcoming 4 in 1 ESC so I could add them to this list.