AK2M4 / XT Brushless Motors

[Fatboy40]

So trusty @ak2m4 has released a batch of their pre-production 34k (assuming on 11.1v) brushless motors, thankfully I had the cash available to buy one, and if you're quick there's one left at £73.50.

God know what I'm going to do with it but with the money available I'm glad I've got one.

I think to start with I'll enable the 20% speed reduction on it and put it in my DMR and see how I get on. Also I've got a work in progress CYMA MP5K, which I'll eventually be using with 7.4v batteries, so it could be a very good option to put in there once it's ready (I need to fit a GATE Titan v3 first).

Anyone else here bought one?

 

[Lozart]

Yep.

 

[Sewdhull]

Yep

 

[Fatboy40]

Cool ?

What are your plans for them / what will you be using them in?

(I'm a bit over excited as this will be my first brushless motor in a RIF, I've used them before in RC cars)

 

[ak2m4]

Thanks guys, fingers crossed this trial works out fine.  If there's any issue at all please get in touch.  Also feedback is appreciated.  If this batch works out fine then I can continue to keep the price low.  I should have a few more by Monday.  

 

[Lozart]

Cool ?

What are your plans for them / what will you be using them in?

(I'm a bit over excited as this will be my first brushless motor in a RIF, I've used them before in RC cars)

I'm upgrading my old G&G SCAR L. New compression parts (all XT - obvs), new XT 6.00mm barrel, changing the BTC Spectre for an Aster (because it's just easier to program) and the XT brushless motor to replace an old green Rocket high torque one. Breaking the cardinal rules of "only change one thing at a time" but hey, fuck it, living on the edge, right?

 

[ak2m4]

@Lozart woah, an AEG make-over.  Let me know how it goes and maybe post a video of before and after please xx

 

[Lozart]

@Lozart woah, an AEG make-over.  Let me know how it goes and maybe post a video of before and after please xx

Unfortunately it's already in bits so the before might be a bit sketchy!

 

[Sewdhull]

Mines going in the Mp5 once I sort out the feed issue

 

[Fatboy40]

Mines going in the Mp5 once I sort out the feed issue

Using 7.4v or 11.1v batteries?

 

[Pseudotectonic]

Watched your video about there is a button to toggle (?) the 20% reduced speed mode?

Sounds like it is entirely digitally controlled so I wonder, does the button only work when plugged in and powered, and if so, how do people actually do this? XD

Install in a pistol grip with the bottom lid open and try to set it in full auto with trigger held down? Sounds a bit risky if the user isn't pressing the button firmly it might grind the gears to dust?

 

[ak2m4]

@Pseudotectonic it doesn't spin when the button is depressed, however if it was me I'd simply remove the motor, connect it to the wires, then set the speed.  it's not something you'd be changing on the fly really.

 

[Pseudotectonic]

Ok I see, because even when it is connected to the wires, unless you are holding down the trigger in full auto, the wires are not powered, so I was wondering how does it even make the sound if it is not powered

--

How accurate is the labelled 34k?

If the 34k is close to 100% efficiency, 34000 / 60 / 18 = 31.48 RPS which is probably in the PME territory, if that is the case, the 20% reduction might be essential to get it down to ~25 RPS

If it is 13:1 gears it is going to PME either way (again if it is close to 100% efficiency)

Does this motor work with ROF reduction or AB? What exactly are the onboard features? Any torque curves or specs in numbers?

Watching with interest

-- PS nevermind I realised you need to hold down the toggle button first, and then press the trigger

 

[strykerles]

Will these motors be coming in the short shaft variety for us V3 users?

 

[Sewdhull]

Using 7.4v or 11.1v batteries?

I'll sort out the feed issues running both, but start with 7.4v, then 9.9v then 11v.

However the gears are 13:1 and the motor might run too fast with 11s.

I wanted a low motor speed, the 22tpa might be too fast on those gears, which I can vary with the perun but I'd rather not have to so I can run with a brushless.

At the moment the bbs don't drop into the hop and rely on the mag spring pushing them into the chamber, which is either hop rubber in the way or nozzle, or a combination of the 2.

I'm not after RPS so 7.4v would be fine but I think the brushless likes 11.1 so we shall see.

I don't think the brushless would like motor speed reduction via the perun.

 

[Sewdhull]

Ok I see, because even when it is connected to the wires, unless you are holding down the trigger in full auto, the wires are not powered, so I was wondering how does it even make the sound if it is not powered

--

How accurate is the labelled 34k?

If the 34k is close to 100% efficiency, 34000 / 60 / 18 = 31.48 RPS which is probably in the PME territory, if that is the case, the 20% reduction might be essential to get it down to ~25 RPS

If it is 13:1 gears it is going to PME either way (again if it is close to 100% efficiency)

Does this motor work with ROF reduction or AB? What exactly are the onboard features? Any torque curves or specs in numbers?

Watching with interest

-- PS nevermind I realised you need to hold down the toggle button first, and then press the trigger

In the video there is mention of speed tests to come.

The actual speed of the motor will be load dependant, but a decent brushless will see higher loaded speeds because of the reduced losses and increased torque usually seen.

The brushless motors that allow ab etc need a capacitor to maintain the voltage to the control electronics on the motor.

I'm unsure if AK has had a peek to see if such a capacitor exists.

 

[ak2m4]

How accurate is the labelled 34k?

I recommend no AB or pre-cock for now, I'm out of Perun's at the moment so can't run any tests, as soon as my supply gets in I'll test.  For anyone desperate to run those I suggest waiting till the 2nd batch arrives (if indeed I do decide on a 2nd batch).  

@strykerles Yep the plan is on for shorts.  Super easy to convert a long to a short if desperate enough

I'm unsure if AK has had a peek to see if such a capacitor exists.

No capacitor that I could see

 

[strykerles]

@ak2m4 nice 1 thanks

 

[ak2m4]

If I get some time this weekend I'll desolder the control board, plus break out my tactometer to get some RPM readings 

View attachment 124554

 

[Fatboy40]

We need "bigclivedotcom" to give us a breakdown on that board ? (they've really pack in those surface mount resistors ? )