First brushless build, what a journey! Air Ro 4"


I am trying to build a 4s 130mm fpv brushless quad using a littlebee 4 in 1 ESC, a RTFquads revo F4 flight controller, DYS BX1306 3100kv motors, and an HS1177 camera.

To my knowledge, I do not need a power distribution board, I guess the power comes from the battery straight to the littlebee 4 in 1, and that then powers the flight controller. I know to add the HS1177 camera I will need to add a pololu…

A few questions.

I see the motor wires must be soldered to the corresponding spots

My question is how do I know what wires are A,B, and C for the motors?

Also, does this build sound like it’s going right so far? I’m desperate to get this thing flying and to start a brushless LOS build… any help would be more than appreciated!


Don’t fret much over the wire order. Unlike with brushed motors where the wire order is important, brushless motors don’t care about which wire goes to which pad on the ESC. At worst, crossing a pair of wires will make the motor spin backwards, which can either be fixed by resoldering the wires or by changing it in BLHeli.

In your case, cross a pair of wires on motors 1 and 4, and don’t cross any on motors 2 and 3. This should have all the motors spin the right way without any further configuration.

Otherwise, the build so far looks like it’s going well.


Thank you for your advice… I sure as heck needed it lol.

So to avoid motor disorientation, when you say cross wires on motors 1 and 4; are you suggesting I solder from left to right on the motor wires #1 to #1, then #3 to #2, then #2 to #3?

And then in motors 2 and 3 solder from left to right motor wires #1 to #1, #2 to #2, then #3 to #3?


What frame is that? Jjrc? Did you per chance grab a bare weight on it before you started building? It looks sweet! You are on the right track so far it looks like anyway. Keep it up and keep posting! That is going to be a ripper. I like that it seems to have room for 1806 motors out on the arms if you wanted to go that route in the future too. Just manage weight above all else - same as micros. Your ripper will turn into a pig the closer you get to 300 grams all up. So far you are building yours exactly how I wanted to do mine - 4 in one - no pdb … but I used parts that were laying around and ended up with old heavy separate escs, a pdb, and 1806 motors. It got fat fast.


Wire them up in the neatest way possible; you can change their rotation in BlHelisuite.

Get some Aluminum M5 nylocks and replace the prop spinners you have. You will save weight/ gain performance.

I see you have a Revo F4 FC. It’s an excellent board. (Although a little antiquated in layout… a beeper takes a little bit of work).

I recommend running Betaflight at least until you get started. Although Raceflight will fly awesome on it when you are ready.


“Wire them up in the neatest way possible; you can change their rotation in BlHelisuite.”

That’s the key. I know it’s hard not to fret over those wires at first, but just wire them up however they naturally fall. You’ll easily be able to change their rotation direction in BLHeliSuite:


I can’t say enough try to solder as neat as possible and plan the wiring for easy disassembly. You will be taking it apart most likely at more than one point in the future. I personally like PDBs because of the filtered voltage and no pololu needed, but it’s not necessary. I’ve taken apart my quads multiple times to upgrade / change components and the thing that bugs me the most is my lazy way with the wires. Twisting the signal/ground… etc.


@adam-g1 Okay, I will do my best to do the cleanest soldering job, and I will fold and tuck the wires as clean as I can. I will try not to let you all down!

@ScottAllyn , thank you for the motor orientation link. Definitely needed if!

@Denovich, I will get some m5 nylon lock nuts for weight savings. thank you for that pro tip. Will start with the beta, then I can be excited for the race flight!

@NotFastEnuf I did not weigh out the bare frame, but if you give me a little time I’ll definitely weigh it out for you. It is an atmospheric adventures apollo 130 . It looks like a total tank with the top plate on. I have good hopes about the 20ax4 littlebee ESC, hopefully it can handle all the rippage :slight_smile:


If I remember correctly @MasterRC_sTudenT built an apollo 130 and has experience with different (motor) setups on that. He’s always willing to help if there a questions


You will be ok mate.

Just be sure of no shorts, and you are fine, any issues will be software if you do that, and they can be sorted pretty easy.

And that 4x1 esc should be fine on those 1306, totally fine.


I know racers using the Racerstar 20A 4-1 with 2206 2400kV motors with no problems. He’ll be fine on a 130 sized build.


@NotFastEnuf the bare frame weight (bottom plate only with no hardware is 28.5g . ) after I took it all apart I went to the website and saw it said 29g bottom plate, 57g total airframe weight with included pdb. I didn’t mind taking it apart though. Makes me feel more in tune with my future ripper! Plus In the process I realized I had to trim standoffs with a razor blade to avoid little black boxes on the littlebee from getting damaged when screwing them in.

@JG101 thanks for the confidence! I will try to do a smooth job on the soldering… I feel like it should be fair! I’ll post update pics when its all soldered up…

@Denovich sweet , it’s good to know the littlebee 4in1 can handle it!


Thanks for weighing it! I’d love to start my next 3" build and so far you are using basically everything that I wish I had put into my first one! You’re definately on a better track than I started out on.
57g total frame weight is AWESOME! No doubt this is going to be one SWEET performer! Hope you don’t mind I’m probably going to run out and grab one of those frames now! Thanks for sharing!


@NotFastEnuf No I don’t do not mind at all! I’m so glad I could share this frame with you. @MasterRC_sTudenT has given me an in detail review of his apollo 130mm build. His looks like such a sick machine. Yes dude, build it up! I wanna see pics of yours if u end up getting one :slight_smile:

So far this is where I am at. I will snip those wires, and get to soldering them all on as soon as I get back from the hobby shop. I feel confident soldering these in nicely with this layout.

Edit: the red rubber bands will disappear! Just holding wires in place for now


Will do, I’m buried in brushed builds right now but I will get something up here when I can get to it. I usually put some large heat shrink on my arms to keep wires tucked and hidden. Works out best to get it on there before you solder wires to the esc. You’d have to take the motors off again, but you get your choice of accent colors on the arms - or black if you dig low profile. Wait to shrink it down till after you solder, if you go for this idea, to keep the wires easy to move before you shrink it down and lock them in place.


Yes @MasterRC_sTudenT was extra cool and took the time to go in depth about his rediculously awesome apollo 130 build. His looks like a blast to fly!


Okay, so good news and bad news.

Good news: I managed to solder all the motor wires to the littlebee 4in1 in an abc order just like the favourite map suggested.

Bad news: I felt like a surgeon who had no idea what he was doing. Lol the solder job is certainly no where near as clean as I was hoping for, but at least it’s all complete and can always be redone when I buy a stronger set of motors. (By the time I got to the last set of motors I felt like I knew what I was doing though :stuck_out_tongue: ) you can tell right off the bat that I am a soldering noobie with my only previous soldering experience being a few scisky FCs lol

Here’s some pics of my masterpiece! :stuck_out_tongue:

Could someone please tell me what the black red white yellow blue and brown wires connect to? At this point I am completely unsure of what part of the build comes next…

I am guessing it stands for ground positive motor 1 2 3 and 4? I just have no clue where to solder those wires to…

This is the FC that I am using…


Going Right to Left, I would guess that:

Red +5V to the + pins on the FC
Black Gnd also to FC

Next four wires are M1-M4 or M4-M1. (Consult your documentation)

They will go to the signal pins, 1-4 on the FC.

That’s a good FC. Lacks some easy features (buzzer/led) but has 16MB flash. Until very recently my best flying quad used that FC (running Raceflight)


As for signal wires (see the sticker on the esc pack, s refers to signal)
Motor 1 (a1, b1, c1) is white.
Motor 2 (a2, b2, c2) yellow.
Motor 3 (a3 …,) blue.
Motor 4 (a4 …) brown.
But esc orientation matters.
The above order is correct if you mount the esc with battery pads to the front and the 6pin signal/bec plug in the back.

Since you changed esc orientation, means rotated esc 180 degrees, you have a different order of signal wires.

Motor 1 (rear right) is now a4,b4,c4 on esc, so it’s the brown signal wire.
Motor 2 (front right) is a3,b3,c3, so blue signal wire.
Motor 3 (rear left) is a2,b2,c2, yellow signal wire.
Motor 4 (front left) is a1,b1,c1, white signal wire.

Hope I didn’t made a mistake, so double check yourself.

All you have to do is solder the signal wires to the corresponding pads on the FC and solder the red (5v) and gnd to power pads.
Have a look in FC documentation to locate the correct pads.


Thanks for the advice! For me this is insanely tough to comprehend, my head starts spinning when i think about how to do this stuff lol

What FC did you end up replacing the revo f4 with on your best flying quad? Newer and greater technology?

@chrisdo Okay, ithink i get what you are saying… I am still processing it all…

They made the littlebee backwards basically?

standard quad x motor formation in cleanflight is: rear right 1, top right 2, rear left 3 rear left 4,

The littlebee esc motor formation when battery leads are pointed backwards is: rear right 4, top right 3, rear left 2, top left 1?

So I need to take that into account when figuring out which signal wire goes where on the FC…

So on the FC I must make sure that motor 1 is the brown wire, motor 2 is the blue wire, motor 3 is the yellow wire, and motor 4 is the white wire. the colors are backwards too!

wow. lol I am sorry you guys I now get it but DANG that was confusing at first.