Brushless motors in the lego world - general topic

[Krxlion]

This topic was raised due to our recent discussion with @Daniel-99 and @FriedlS, thus can be used to discuss ways of implementing brushless motors to our lego technic creations. We may also speak about other modifications that surely comes with implementing brushless motors like transmitters, receivers, ESCs, ball bearings, printed parts, etc.

To start of, I want to get everyone a picture what we need to power our models with brushless motors:

• Brushless motor - for example A2212 1000KV 2-3s (A2212 - meaning model type and dimensions, 1000KV - how many turns does motor make when we power it with 1 volt , 2-3s - which type of battery does motor support).
• Transmitter - for example DumboRC X6FG (good starting transmitter that often comes with suitable receiver, which supports gyro function - it helps the model go in straight line using countersteering).
• Receiver - like mentioned above.
• ESC - heart of brushless setup. Think of it as lego technic hub that you connect all motors and receiver to it. The ESC must be bidirectional, usually for mentioned above motor 30-35A should be enough. You may go with SurpassHobby 35A ESC.
• Servomotor - GeekServo, simple, does it job and is easy to implement in lego models due to pin holes in it.
• Battery - usually we can choose between 2s and 3s. Second option is more powerful but often simply bigger. My choose was GensAce LiPo 1800mAh 3s 11.1V 45C, but I find it now too big.
• Battery charger - for example iMAXrc B3. It is cheap and simply does the job, but you can get a better one, suited exactly to your battery capacity and number of cells.

If you have any doubts what to choose or how to start, feel free to ask, that is especially the case why this topic was raised. There are some things that you need pay attention one, like matching connection plugs of your ESC and battery, how to transfer RPMs from motor's shaft to lego gears, how do you plan to hold your motor in lego model (usually screw the motor to the liftarm using M2 or M3 bolts).

Just to not leave this topic without any questions or discussion I want to ask mentioned above guys few more things:

1. @FriedlS you mentioned one of previous posts that you are using carbon axles, may I ask where do they come from?
2. @Daniel-99 are those housing of A2212 brushless motors are available as printable files so I can try to print them on my own?
3. Do you guys know what other cool brushless motors we may use in our setups?
4. @FriedlS do you know the dimensions of those ball bearings that you've been using in your recent model? Maybe we can fit them in technic liftarms or frames if we would additionally drill slightly bigger holes in them?

 

 

[aFrInaTi0n]

Even if I am not Friedl, for the ballbearings: I am very happy with the 5L aluminium liftarms with a pressed in bearing in the mid hole from MTP, reference: 

Also there is another rising star with 3d printed parts, a review of their items will be posted in the next days by myself. (3D printed 3L liftarms with different options (pin / axle holes, aligned or as flipflop), they also offer ballbeared wheelhubs).

They should arrive in the next days... 🥰

 

Carbon axles are offered by some (reseller-)brands from our far-east friends..

 

My personal opinion about using regular RC:

Right now it feels (for me at least) somehow wrong using such as it is "not really brick-compatible" parts - even if brushless motor mounts may fit the spacings of LEGO liftarms etc..

On the other side I am really disappointed by Buwizz with their "premium price" product which doesn't really performs in some regards..

 

What I am really missing is RC components which are being fitted to be used in the brick world, like receiver, ESC and battery casings which respect the Lego (Technic) format. How wonderful would it be to freely place the needed components into different places and also have the power of 2s batts with brushless motors.

I am especially a little bit wondering why CaDA is going with another line of brick-based/-fitted components which are not really an improvement (I know, I know, they may wan't to divert away from LEGO as it may get hard to get the PU connectors replicated without doing copyright infringements) - but with DoubleEE in their back would have the wisdom and also the money to think about trying those out - even maybe as a simple rc kit to see responds from the community, without directly aligning all their future sets for those components.

Edited March 14, 2023 by aFrInaTi0n

[Daniel-99]

9 hours ago, Krxlion said:

1. @FriedlS you mentioned one of previous posts that you are using carbon axles, may I ask where do they come from?
2. @Daniel-99 are those housing of A2212 brushless motors are available as printable files so I can try to print them on my own?
3. Do you guys know what other cool brushless motors we may use in our setups?
4. @FriedlS do you know the dimensions of those ball bearings that you've been using in your recent model? Maybe we can fit them in technic liftarms or frames if we would additionally drill slightly bigger holes in them?
 

1. I use carbon axles as well, they have been purchased at AliExpress. The quality is good. 

2. I dont have the 3D model of the housing, and it`s designer sell only printed parts but not 3D models.

8 hours ago, aFrInaTi0n said:

Also there is another rising star with 3d printed parts, a review of their items will be posted in the next days by myself. (3D printed 3L liftarms with different options (pin / axle holes, aligned or as flipflop), they also offer ballbeared wheelhubs).

They should arrive in the next days... 🥰

I think this will be the best solution for Lego. Both hubs and beams will be great to use!

 

8 hours ago, aFrInaTi0n said:

My personal opinion about using regular RC:

Right now it feels (for me at least) somehow wrong using such as it is "not really brick-compatible" parts - even if brushless motor mounts may fit the spacings of LEGO liftarms etc..

On the other side I am really disappointed by Buwizz with their "premium price" product which doesn't really performs in some regards..

What I am really missing is RC components which are being fitted to be used in the brick world, like receiver, ESC and battery casings which respect the Lego (Technic) format. How wonderful would it be to freely place the needed components into different places and also have the power of 2s batts with brushless motors.

Agreed! regular RC bring a bit of a mess into the cars. Though i love the fact that I can put components in the different places. It brings so much possibilities! Also it is easy to swap component to a new one, and upgrade your setup (it is easy to do since RC component are wide-spread). Finally, it is way cheaper than Buwizz products, and provide a lot more power.

 

8 hours ago, aFrInaTi0n said:

I am especially a little bit wondering why CaDA is going with another line of brick-based/-fitted components which are not really an improvement (I know, I know, they may wan't to divert away from LEGO as it may get hard to get the PU connectors replicated without doing copyright infringements) - but with DoubleEE in their back would have the wisdom and also the money to think about trying those out - even maybe as a simple rc kit to see responds from the community, without directly aligning all their future sets for those components.

I wish they would do RC kits as well! Maybe we should make a collection of RC Lego cars to show the possibilities of the system, and after that contact CaDA. 

[FriedlS]

21 hours ago, Krxlion said:

This topic was raised due to our recent discussion with @Daniel-99 and @FriedlS, thus can be used to discuss ways of implementing brushless motors to our lego technic creations. We may also speak about other modifications that surely comes with implementing brushless motors like transmitters, receivers, ESCs, ball bearings, printed parts, etc.

To start of, I want to get everyone a picture what we need to power our models with brushless motors:

• Brushless motor - for example A2212 1000KV 2-3s (A2212 - meaning model type and dimensions, 1000KV - how many turns does motor make when we power it with 1 volt , 2-3s - which type of battery does motor support).
• Transmitter - for example DumboRC X6FG (good starting transmitter that often comes with suitable receiver, which supports gyro function - it helps the model go in straight line using countersteering).
• Receiver - like mentioned above.
• ESC - heart of brushless setup. Think of it as lego technic hub that you connect all motors and receiver to it. The ESC must be bidirectional, usually for mentioned above motor 30-35A should be enough. You may go with SurpassHobby 35A ESC.
• Servomotor - GeekServo, simple, does it job and is easy to implement in lego models due to pin holes in it.
• Battery - usually we can choose between 2s and 3s. Second option is more powerful but often simply bigger. My choose was GensAce LiPo 1800mAh 3s 11.1V 45C, but I find it now too big.
• Battery charger - for example iMAXrc B3. It is cheap and simply does the job, but you can get a better one, suited exactly to your battery capacity and number of cells.

If you have any doubts what to choose or how to start, feel free to ask, that is especially the case why this topic was raised. There are some things that you need pay attention one, like matching connection plugs of your ESC and battery, how to transfer RPMs from motor's shaft to lego gears, how do you plan to hold your motor in lego model (usually screw the motor to the liftarm using M2 or M3 bolts).

Just to not leave this topic without any questions or discussion I want to ask mentioned above guys few more things:

1. @FriedlS you mentioned one of previous posts that you are using carbon axles, may I ask where do they come from?
2. @Daniel-99 are those housing of A2212 brushless motors are available as printable files so I can try to print them on my own?
3. Do you guys know what other cool brushless motors we may use in our setups?
4. @FriedlS do you know the dimensions of those ball bearings that you've been using in your recent model? Maybe we can fit them in technic liftarms or frames if we would additionally drill slightly bigger holes in them?

 

 

Hi,

i use the carbon axles from aliexpress. In my trophy truck these one works pretty well. 
i use this bearings:

https://www.kugellager-express.de/stainless-steel-miniature-deep-groove-ball-bearing-inch-ss-r156-w2-779-open-oiled-4-762x7-938x2-779-mm
 

[aFrInaTi0n]

@FriedlS How do you mount them to lego pieces if I may ask?

[Krxlion]

47 minutes ago, FriedlS said:

Hi,

i use the carbon axles from aliexpress. In my trophy truck these one works pretty well. 
i use this bearings:

https://www.kugellager-express.de/stainless-steel-miniature-deep-groove-ball-bearing-inch-ss-r156-w2-779-open-oiled-4-762x7-938x2-779-mm
 

I love it! I believe you would need to drill bigger hole to fit it for example in liftarm. The problem is that liftarms are around 7.38mm high which is not enough, you would simply cut the piece in two.

I also wanted to mention one thing about lubrication. I received today a package with white lithium grease and after some initial tests I must say I find it better than silicone grease which I used to this moment. With new lubricant I can move more easily main drive shaft and what is more important it sticks better to the gears and does not splash away that easily during high RPMs.

[Daniel-99]

I found this video quite related to out topic: 

 

[Krxlion]

Currently my model has THIS way of transfering power from the motor to lego model. I find it more "clean", I do not like mixing my bricks with superglue or anything of that sort, haha. You may take a look at other videos of this person channel, they are quite usefull for brushless enthusiasts like us.

Edited March 16, 2023 by Krxlion

[FriedlS]

22 hours ago, aFrInaTi0n said:

@FriedlS How do you mount them to lego pieces if I may ask?

Every question is welcome 😊

i use this one 

I found this STL file here on eurobricks. 

This company creates also liftarms with ballbearings:

https://tf-engineering.at
 

[aFrInaTi0n]

@FriedlS I see....

So I will test those this weekend hopefully :)

[gyenesvi]

Interesting topic, thanks guys. What I have been wondering about motors is not only having much faster or more powerful ones, but rather having the same power/speed as we have for example for 2 coupled PF L motors, but at a much smaller form factor. Something like a single M motor. Do you guys think there exists such a motor? That would be really interesting for smaller scale RC cars, coupled with a geekservo for steering.

By the way, +1 for having a lego compatible RC system or even just casing for such components available from any producer :)

[FriedlS]

9 hours ago, gyenesvi said:

Interesting topic, thanks guys. What I have been wondering about motors is not only having much faster or more powerful ones, but rather having the same power/speed as we have for example for 2 coupled PF L motors, but at a much smaller form factor. Something like a single M motor. Do you guys think there exists such a motor? That would be really interesting for smaller scale RC cars, coupled with a geekservo for steering.

By the way, +1 for having a lego compatible RC system or even just casing for such components available from any producer :)

You mean something like that:

 

[gyenesvi]

1 hour ago, FriedlS said:

You mean something like that:

Yes, something like that :) The question is what's the speed / torque of that motor. I was wondering if there's something that's not too fast, but powerful enough, because, as we know too much speed is problematic for all lego components along the drivetrain. If only fast motors exist, maybe a lot of planetary reduction could be used to make the output slow and torquey on a small motor? I'm thinking about an RMP around 400-500 with a torque of 40-50 Ncm. That's in the range of 4x M motors or 2x L motors. Another setup that could be interesting is double the speed but half the torque, so around 800-1000 RPM and 20-25 Ncm torque. All of these in the size of a single M or L motor.

[Krxlion]

7 hours ago, gyenesvi said:

Yes, something like that :) The question is what's the speed / torque of that motor. I was wondering if there's something that's not too fast, but powerful enough, because, as we know too much speed is problematic for all lego components along the drivetrain. If only fast motors exist, maybe a lot of planetary reduction could be used to make the output slow and torquey on a small motor? I'm thinking about an RMP around 400-500 with a torque of 40-50 Ncm. That's in the range of 4x M motors or 2x L motors. Another setup that could be interesting is double the speed but half the torque, so around 800-1000 RPM and 20-25 Ncm torque. All of these in the size of a single M or L motor.

You can also take a look at this guy:
http://www.youtube.com/watch?v=qgf4Vfnd5Hg&t

He found brushless motor that fit exactly in Lego PF M motor, you may also find brushless motors in same size but with more torque instead of speed. :)

Edited March 18, 2023 by Krxlion

[wower]

On 3/18/2023 at 7:17 AM, FriedlS said:

You mean something like that:

 

YES!! But i suppose thats your own DIY? Could you explain to me idiot-proof where to buy what (and where to get a remote for that that looks like a classic remote, not those huge thingies with a wheel and a pistol-trigger) please :-)

[vergogneless]

On 17/03/2023 at 12:41, aFrInaTi0n said:

@FriedlS Je vois....

Je vais donc les tester ce week-end j'espère  :)

Hi ! So you could test? I am interested in this solution 

[aFrInaTi0n]

Unfortunately not had any time to test those and create some good footage - I hope for being able to do so this or next weekend.

Sorry for lagging behind with that..

[Krxlion]

Hi guys,
I just wanted to share with you the concept of using A2212 Brushless motor to drive front and back axles at the same time.

Link to GALLERY of few photos, so you can see the whole concept and understand what I will further say.

In this case the two yellow 2L axle connectors are driven by this single A2212 BL motor. This is done due to slight move of the shaft to the back. I needed to glue them in place though and slightly sand one of them down, so they now fit exactly to Lego stud diameters perfectly (7 stud long whole setup from one yellow axle connector to another). I must say though that I am bit disapointed by the perfomance. In my previous MOC - Trophic, I was using different BL motor and it could handle two driven axles no problem on full load. In case of this setup, first I tested it without gearing (by planetary hub you see above) and it couldn't rotate ONLY front wheels and without load on them. 

After that I attached the gear reduction you see (planetary hub) and tested it on front axle. The result was okay, output speed is not compared to "Trophic" MOC though, if I would guess. What I wanted to achieve is a small motor setup, working already on both axles and without need of further reductions (except those in differentials) but this concept fails me on that.

I will keep you guys posted and If you have any suggestions or simply want to share something regardin our topic, please feel free. 

[vergogneless]

Le 19/04/2023 à 19:17, aFrInaTi0n a dit :

Malheureusement, je n'ai pas eu le temps de les tester et de créer de bonnes séquences - j'espère pouvoir le faire ce week-end ou le week-end prochain.

Désolé d'avoir pris du retard avec ça..

D'accord :)

19 hours ago, Krxlion said:

Salut les gars,
je voulais juste partager avec vous le concept d'utilisation du moteur sans balais A2212 pour entraîner les essieux avant et arrière en même temps.

Lien vers  la GALERIE  de quelques photos, afin que vous puissiez voir l'ensemble du concept et comprendre ce que je vais dire plus loin.

Dans ce cas, les deux connecteurs d'axe 2L jaunes sont entraînés par ce seul moteur A2212 BL. Cela se fait en raison d'un léger mouvement de l'arbre vers l'arrière. J'avais besoin de les coller en place et de poncer légèrement l'un d'entre eux, de sorte qu'ils s'adaptent maintenant parfaitement aux diamètres des goujons Lego (7 goujons de long ensemble d'un connecteur d'axe jaune à un autre). Je dois dire cependant que je suis un peu déçu par la performance. Dans mon précédent MOC - Trophic, j'utilisais un moteur BL différent et il pouvait gérer deux essieux moteurs sans problème à pleine charge. Dans le cas de cette configuration, je l'ai d'abord testé sans engrenage (par moyeu planétaire que vous voyez ci-dessus) et il ne pouvait pas faire tourner UNIQUEMENT les roues avant et sans charge sur celles-ci. 

Après cela, j'ai attaché la réduction de vitesse que vous voyez (moyeu planétaire) et l'ai testée sur l'essieu avant. Le résultat était correct, la vitesse de sortie n'est pas comparée au MOC "Trophy", si je suppose. Ce que je voulais réaliser, c'est une petite configuration de moteur, fonctionnant déjà sur les deux essieux et sans avoir besoin de réductions supplémentaires (sauf celles des différentiels), mais ce concept me manque sur ce point.

Je vous tiendrai au courant et si vous avez des suggestions ou si vous voulez simplement partager quelque chose concernant notre sujet, n'hésitez pas. 

Nice concept !

 

On my part, I present to you my very first brushless project!

 

With the A2212 :D

[Daniel-99]

2 hours ago, vergogneless said:

 

On my part, I present to you my very first brushless project!

 

With the A2212 :D

Hey! Welcome to our small Brushless club ;-) 

[vergogneless]

1 hour ago, Daniel-99 said:

Hey! Welcome to our small Brushless club ;-) 

Thanks :D

[vergogneless]

On 4/19/2023 at 7:17 PM, aFrInaTi0n said:

Unfortunately not had any time to test those and create some good footage - I hope for being able to do so this or next weekend.

Sorry for lagging behind with that..

Hi aFrInaTi0n!

 

You have probably not yet tested these products, and I apologize for coming back to you again on this subject lol. But I believe you are the only one on the internet who owns them, I have searched everywhere and cannot find any user feedback. I am about to place a large order with them but I still have a small doubt.

 

I simply want to know if this solution completely eliminates the lack between the wheelhub and the driveflange? In other words, does it eliminate the wobble effect when the wheels are connected? Because I see that a Lego driveflange must be connected and that's what worries me!

 

And by the way, the same question seems to apply to the flangebearing!

 

Ultimately, I am afraid of being disappointed because of the high shipping costs, I am almost obliged to place a large order to make it profitable. And even if I am convinced that the frictions will be significantly reduced, I have this big doubt regarding the lack :( 

 

[aFrInaTi0n]

@vergogneless Sorry that I still wasn't able to deliver something, maybe that short 36 seconds video helps to get a glimpse:
 

 

I was pushing gently but not forcing the housing to break or something... I would say the bearing and the mount for the wheel is a tight fit.

[vergogneless]

44 minutes ago, aFrInaTi0n said:

@vergogneless Désolé que je n'ai toujours pas pu livrer quelque chose, peut-être que cette courte vidéo de 36 secondes aide à avoir un aperçu :
 

 

Je poussais doucement mais sans forcer le boîtier à se casser ou quelque chose comme ça... Je dirais que le roulement et le support de la roue sont bien ajustés.

Great, thanks for the short video! It already allows me to see and it seems pretty good, definitely much better than the Lego solution lol.

[janssnet]

Thanks for initiative @Krxlion, love this subject! 

Great to read about your experiences and additions. 

Have been incorporating brushless into my LEGO project for years. Lots of fun. Please find the latest attached: RIB with brushless (drone) outboard motor

Was thinking of doing a short video/slide deck: Top 5 mounting tips to run your LEGO project brushless. Useful you think?

https://www.flickr.com/photos/153697698@N03/52809695671/in/dateposted/

https://www.flickr.com/photos/153697698@N03/52809132637/in/dateposted/

 

 

Edited June 1, 2023 by janssnet