Brushless

The new “Favorite” FVT LittleBee 20a arrived into the HacksMods lab. So it’s time to take some clear shots of them and compare with the Flyduino KISS ESC. Which is still one of the highest performing multirotor electronic speed controller. The small size and light weight are great for putting on racing quads. Or burying inside heavier aerial photography equipped quadcopters, or “drones” as the media likes to call it.

In the USA, the Little Bee 20a are known as the MRM Zeus 20. Brian (punkindrublik on RCGroups) of  MultiRotorMania help finance and brought these new ESC to market. So they secured the rights as the sole distributor in the USA. However, the ESC should soon be available from some of your favorite multi rotor online stores.

Continuing in the same small by mighty form factor that the Flyduino KISS ESC brought to market, the FVT LittleBee 20 are about the same size. 12.5mm x 23mm x 3mm. Versus the KISS (v1.1) 12mm x 24mm x 3.81mm

What makes these new FVT LittleBee the current popular ESC is that recent test are showing them to perform similar to the KISS ESC. (Here’s one by QuadMcFly) This is in part due to the use of the SilLab F330 MCU. Which has a faster clock speed than the popular ATMEL chip used on most competing ESC. Add to that dedicated FET drivers and it’s performing quite well. This is what BLHeli creator Steffen has to say about it:

Then there is a very promising little ESC, the FVT Littlebee 20A:

This ESC has a good design with fast dedicated driver chips, which gives excellent freewheeling and exceptional braking.

Initial stress testing on 4S with a Cobra 2208/2000 with 6×4.5 prop, doing repetitive immediate accelerations from low rpm to full throttle went well.
During the initial acceleration, this setup pulls about 100A, so it’s a tough test for a small ESC (and can break other small ESCs).
Hopefully this indicates that the ESC will prove to be a reliable performer.

And so far, this is the closest performer to KISS that I have seen in this size.

Very clean layout and manufacturing placement of components on the PCB. Definitely KISS quality for sure. It seems like they used higher temp lead free solder. My Metcal MX500 soldering station usually makes quick work with lead free solder. But I admit, it took a split second longer with the solder joints on these Little Bee 20. This may be to prevent overheated MOSFET from desoldering itself like what appears the DYS SN20a are doing in some of the recent batches. Also, keep in mind that having to flow the solder at a higher temp usually slows down the manufacturing process. This, along with how clean the ESC looks and components are laid out…continue to signify a high level of quality control. So kudos to Favorite and MultiRotorMania.

Weight of the FVT LittleBee 20a as it came out of the package is 6.73g.

Weight of the FVT LittleBee 20a without heatshrink and wires is 2.12g. I know some of you guys want to know things like this. I know as a hobbyist, I do. So very similar to the KISS 18a which I weighed here. And about .70 grams heavier than the ZTW Spider 18a Opto Lite.

Signal wire polarity in case someone needs this info in the future. (That’s would usually be me.)

I have a few new frames I’d like to use these LittleBee on. Can’t wait to see them fly.

Some of my favorite places to buy from that carries these FVT LittleBee/MRM Zeus 20:
USA
MultiRotorMania: MRM Zeus 20 Amp ESC
BangGood: FVT LittleBee 20 Amp ESC

Australia
ImpulseRC: FVT LITTLEBEE 20A ESC
BoltRC: Little Bee 20A ESC

China
BangGood: FVT LittleBee 20 Amp ESC
MyRCMart: RCX 20A (Little Bee) Mini BLHeli Multirotor ESC

Europe
MultirotorParts: Favourite Littlebee 20A
Supreme FPV: Littlebee 20a esc 2-4s

More info can be found on RC Groups discussion thread:
Little Bee and MRM Zeus 20AMP ESC’s

With DYS/RCTimer SN20a and BL20a possibly having a bad manufacturing batch. Plus, you lose about 10% thrust versus competiting ESC. One of the new ESC some of us have started buying instead are the ZTW Spider 18a Opto Lite as some retailers are calling them. Performance seems good so far. We’ll learn how their fare in crashes and general abuse as more and more people use them and report back.

The BLHeli firmware to use are BS12a or BS20a. either hex will work fine according to sskaug (Steffen), BLHeli creator.

Mine came with the SimonK bootloader. And I was able to use my USBASP to flash BLHeli bootloader on there. Here are the ISP pad locations for your reference:

Weight as they come out of the package. I took off the heatshrink and it was about .2g lighter.

Heatshrink is thin, clear and shiny. Same types they use on many battery packs.

Weight of the naked ESC.

Here’s a shot of the ZTW Spider Lite on the far right. Next to it is the new KISS 30a. And to the far left, is the KISS 18a.

Picture of the MOSFETs and a peek at the soldering. I don’t see any left over solder splashes/balls.

KISS 18a on the left. ZTW Spider 18a Lite on the right side.

Side by side with the KISS 18a v1.1. Which is simply about 1mm longer than KISS 18a v1.0. You can see that the ZTW Spider 18a is slight shorter. And also thinner.

A look at the opposite side.

Here’s the Spider 18a Lite mounted in the lower plate of the Aura 250 FPV quad.

And a couple of closing shots of the Aura 250.

I modified the top plate so I can slide in a 4S 1400mAh lipo pack.
The links below are my favorite places to buy:

USA 

Readytoflyquad: 18a Spider Lite Series ESC
MassiveRC: MassiveRC OneShot125 18a ESC

China
BangGood : ZTW Spider Series 18A Lite

I got the new RCTimer SN20a ESC in today. These are the new crop of ultralight and small ESC, using the latest MOSFET tech. It all started with Flyduino’s KISS ESC.

The first thing I did was desolder all the wires. Then gave it a quick inspection. Follow by some photographs of them sidebyside with the KISS 12A ESC v1 I have.

The KISS are supposely 12mm by 23mm. I measured with my digital calipers at 12.25mm by 23mm. While the SN20a measured at 11.94mm by 23.33mm.

So they are both roughly the same size. However, keep in mind that the latest KISS v1.1 have larger pads so they gain about 1mm in length. It’s nice to see that the SN20a ESC comes with larger pads by default.

The other pluses for the SN20a is that all the wires come presoldered and the ESC heatshrunk. And best of all, the 20A are less than $12 in qty of 3 or more!!!

Runs BLHeli with dampening and OneShot capabilities.

And near identical in weight as well…

And thanks to Zachary, he pointed me to the pinout someone shared on RCGroups.

Discussion Thread:
RCGroups thread: RCTimer / DYS Mini SN20a esc

For flashing…I suggest getting an Arduino Nano. You can use BLHeli Suite to program it into a 4 interface flashing toolstick. This will allow you to flash SN20a ESC with either SimonK or BLHeli bootloader as well as other things. This makes it the most versatile toolstick…and least expensive too at < $4 shipped from the USA warehouse. I’d grab a 3pack or 5pack just to have extra. For friends or other projects that require the Arduino. ;)
The links below are my favorite places to buy:

USA 

BangGood USA Warehouse: DYS SN20A with BLHeli Mini 20A SimonK ESC OPTO
MassiveRC: SN20A OneShot125 20A ESC

Canada
Armattan (blheli pre-flashed) http://www.armattanminis.ca/armattan-20a-opto-esc/

China
BangGood : Rctimer OPTO mini 20A Brushless ESC SimonK 2-4S for RC Multicopter
RcTimer : http://www.rctimer.com/product-1280.html

**Update 2015-07-28** DYS rep recommend updating to BLHeli 14 to avoid any issue of burnt ESC.

Pivotal moment for those of us who loves the opensource BLHeli brushless firmware from Steffen. HiSky’s new HCP100S double brushless micro CP helicopter comes with BLHeli firmware already flashed onboard. Not only that, the programming pads are big and accessible.

BLHeli toolstick connection points…

Main ESC was flashed with BLHeli 12.1. Governor modes are disabled. But Programming by TX is left enabled. Therefore, you should be able to use your transmitter sticks to enable/disable some of the features. Read the BLHeli manual under section for Beeps – Entering programming mode. The manual can be founded in the /manual folder after you download and unzip the BLHeli Suite software

(Another good read… DoubleCH explaination of governor modes)

The best method for updating BLHeli settings and flashing new firmware is by using a SilLabs based flashing stick in combination with the BLHeliSuite software you see below:

Here’s the pinout for that flashing stick from BangGood listed above.

Tail ESC was flashed with BLHeli version 10.4

And for you HCP100, v922, FBL100 and even mCPX owners. Here’s how it can look like if you repurpose the HCP100S dual brushless ESC for your heli…

Lovely spring weather means I am antsy to build and fly again. I am planning on using this Hobby King HKing 10a brushless ESC in a 230mm size acro quad. Not sure if it will be able to endure SunnySky 2204 2300kv with 3s lipo but I like the physical size…so I will give it a try anyways.

Anyways, the dimensions on Hobby King is incorrect (23mm x 18mm). Here are the actual values as measured with the digital caliper. The bare ESC as pictured weighs 2.59g.

It arrived with 20guage silicone wires for the main power. And 22gauge silicone wires for the motor leads.

Missing from the photo is the electrolytic capacitor (100uf 16v). I took it off so I can use a tantalum SMD capacitor with the same values. It’s much smaller physically. Hopefully it works out. :)

What I like about this ESC is the fact that it’s BLHeli compatible. Plus, it uses all N-channel MOSFET. And it was reasonably inexpensive at $5.78. Here’s an inexpensive BLHeli programmer, and another another. You will need one of these for flashing the firmware or updating the parameters of the ESC using the BLHeli Suite software. Unless you already have an official SilLabs Toolstick. Then you can follow this guide for modding it for the same function.

Just stuck a brushless motor into the v911 pro frame.

Flights felt underpowered. I think it will need a larger pinion. I didn’t play with it too much so I can’t tell if we can get the v911 to actually fly better. Additionally, you’ll need to reinforce the main frame after cutting away the vertical struts to make room for the brushless motor.

In almost all aspect of life, having the right tool makes the job much easier. When flying micro helicopters and quads, everything has to be micro sized in order to avoid adding unneeded weight that may robs the motor of it’s performance.

For wires, magnet wires, also known as enamel wires, are a must have in your tool kit. The bigger brand names such as Horizon Hobby with their Blade lineup of heli, uses magnet wires for their antennas and for the tail motor. Nine Eagles is another manufacturer that uses magnet wires to extend to the tail motor.

I find that a good gauge for these wires are about 30-32 AWG, measuring about 0.0085in or 0.02mm. You can find magnet wires if you search for them online. Locally, my Fry’s Electronics and Radio Shack have them in spools that will last you a long time.

Alternatively, you can find the right gauge magnet wire in small motors often used in toys. Also, fans used in computers is often another source, though I find they can sometimes be thinner than 32ga.

Perfect 32ga magnet wire for these small motors

Simply take apart the motor and unravel the wire. Taking care not to rub against the rough armature and accidentally nick the enamel coating of the wire. One motor yields a lot of wire. After taking them off, you’ll see they are wavy and kinked.

A trick I use is to simply hold a section of the wire between each hand and running them back and forth against the edge of a a cutting mat, metal rod, or any edge that will not nick the wires and will not get damage if the wire start to cut into it. This trick will quickly straighten out the wire with a couple of passes. See the photos below…

Rubbing the wires back and forth along the edge of a table, metal rod or cutting mat will straighten out the kinks of the wire

To solder these magnet wires, you have to remove the enamel that coats the copper of the wire. The enamel is to prevent the wires from shorting out while wound up in the motor. Some people may scrape the thin enamel coating off. The trick I learned is that the enamel coating can be quickly burned off and the wire tinned at the same time using solder.

I put a blob of solder on the tip of my iron and touch the end of the magnet wire to it.

Touch the end of the magnet wire to a solder blob for a second to strip the enamel and tin it at the same time

It takes but a second and you get a perfectly tinned tip, ready to be solder. Easy peasy. :)

Perfectly tinned magnet wire without any hassle

Another tip for you. If you want to lower the overall resistance and thicken up the gauge of the wires, you can twist a few strands of the magnet wires together. I do this by putting one end into the power drill and hold the opposite end. The hand held power drill will make a perfect twisted bundle of magnet wire.

Put a few strands or more of magnet wire to a power drill and it will create a perfect twist

Here, you can see that three 32ga magnet wire twisted together has more copper than the original stock wires that feeds through the v929 boom. Because each wire has the enamel coating, despite having more overall copper, the twisted bundle is equal to the thickness of the original wires with it’s insulation. Which means you can still feed a positive and negative pair through the carbon fiber boom.

Three strands of 32ga magnet wire to replace original stock v929 boom wire

I like to use the magnet wire because it’s cheap, lightweight and it’s coating looks like anodized metal.

One final trick, for aesthetics, I will use the same color for positive and negative. To keep track of the polarity, I simply mark the each ends of the negative wire with a black sharpie so I properly solder it to the negative terminal. Twisted togther, they looks like an performance “upgrade.” :D The cooler looking it is…the faster it goes. ;)

That’s all there is to it.  Hopefully this post helps you guys. Happy modding!!!

A bad mCPX brushed tail motor prevented the test flight of a brushless mCPX. So I had to get creative with the stuff I had on hand. No store to run to at 12AM. Here’s the result. A Hobby King AP-03 brushless motor and a Blade 120SR tail boom.

Worked really well too with a XP 3A ESC flashed with BLHeli tail code.

Mated a Hobby King AP-03 Brushless Motor to a 120SR tail boom and motor mount.

7/9/2012 Update:

I saw that there are some people who do view my post…and so perhaps some more thoughts on using the HobbyKing AP-03 motor is needed.

It works good…but obviously you gotta mod a mount for it.

I like that it’s relatively cheap from Hobby King ($15). The negative thing is, the shaft size is 1.5mm. Which means you gotta bore out that size on the prop you wanna use. I like the RRC 65mm Tail rotor blade because it has a larger center hub so you can enlarge the default 1mm hole to fit the 1.5mm shaft. Also, with the AP-03 as it comes from HobbyKing, you have to reverse the shaft. It’s easy to do with a drill press and a small socket. I’ll try and do a post on it if there’s demand. I also recommend you get a 1.5mm to 1mm replacement shaft and replace the shaft that comes on the AP-03 motor. That way, you don’t need to bore out holds on the tail prop. Fabricating a tail mount may be too much work, so if you don’t have the motor laying around to use…I’d just grab a Oversky HP03T motor and be done with it. :D

1/16/2013 Update:

I have flown the mCPX with this tail more, as well as crashed it more. And everything is still great. Had to replace one broken Plantronics tail rotor. Other than that, solid so far. I replaced the 1.5mm shaft with a 1mm shaft from Astroid-Designs so now changing props is not a hassle.

There were some confusion on what’s the minimum things to plug in to properly flash BLHeli onto the the ESC. I know I had the same questions when I started out and when you run into a problem, there are too many variables to contend with.

An overhead view of how I have mine set up. You don’t need anything more than this to properly flash the ESC.

The minimum setup to allow BLHeli flashing.

And for completeness, here is the order of how I hook things up.

1. First, I connect the ESC to the USB Toolstick.
2. Next, I connect the USB Toolstick to the computer.
3. Finally I connect the battery to the ESC to power it up.

I then open up the BLHeliSuite program that user 4712 from HeliFreak wrote.

I click on the “Flash BlHeli Hex File” button. Then select the proper firmware I want to flash over and hit the “OK” button to flash the new firmware onto the ESC. (You’ll get prompted with a couple of dialog boxes warning that you’re about to overwrite the original firmware on the ESC. I just answer ok to dismiss them and continue on.)

Let me know if that helps you or if I need to clarify any steps.

Just wanted to share the evolution of my mSR X brushless mount.

I find it’s easier to design on the computer. A digital caliper is a great tool to transfer the measurements into your graphics program. A CAD program is ideal. I am more familiar with Illustrator, so that is what I used. If you can scan your object, you can use that scan as an overlay to trace it’s physical dimensions. Doing it this way allow you to make precise changes on the computer. The low tolerance and need for higher precision is very important at the size of these micro helicopters.

Here’s a previous design for the AP-03 motor. Unfortunately, this motor wasn’t enough power for the mSR X.

Prototype of the mSRX AP03 brushless motor mount. The AP03 doesn't have enough power for the mSRX.

Then print and cut out some on paper. Or you can print onto label paper that you can peel and stick to a plastic credit card. This allow you to cut out the prototype with a xacto knife and scissors. You’ll find you need to do a few to narrow down the design.

Various mSR X AP03 prototypes on paper and plastic

Once you’re happy, you use the same method of printing onto a label paper and sticking it on top of the material you want to make the mount out of. I used 0.8mm weaved carbon fiber sheet. I used a dremel and freehand the cut out and a file to clean up the shape. It wasn’t too difficult work, and didn’t take too long at all. However, if you have access to a CNC router, the prototyping stage goes by so much faster and easier.

Here’s a couple of photo of the final result. I consider it a prototype, but it could qualify for production work. It’s very polish and wowed the owner of the mSRX and friends who have gotten to see it in person.

I felt that the stock mSR X was very underpowered the first time I got to fly it. Because it was underpowered, I couldn’t bail out of bad situations. The positive quality of the mSR X is quickly the flybarless heli respond to your cyclic command. It was near instant. It’s a pity that it lacks power. On top of that, there seem to be a huge problem where the stock brushed motor tend to die very early deaths. There’s a whole thread from owners tracking the issue.

After the mod to a brushless motor, the mSR X finally has the pop I like to see in my micro heli. I personally think it should have came this way from the factory. It is definitely worth it for those with mSR X. The brushless ESC, motor, mount and wires all weigh less than the stock brushed motor. Isn’t that amazing?

Stay tune for the rest of the how to’s on this series. Until then, take a look at preparing for flashing the ESC here: Silicon Labs USB Toolstick Mod for BLHeli Flashing