One thing about the RDY-5536 motor I forgot to mention: When you first spin up the motor to full speed it might draw a surprising amount of current (>10 amps) for a minute or two even with no blade on it. This seems to be from the bearing grease warming up and spreading around evenly. Once its up to speed for a couple minutes the current will drop back down to a normal ~1-3 amps at no load and it should stay that way even after the motor has cooled. You also might find some of the bearing grease has leaked out, which should not cause any problems.
Being able to buy separate magnet rings is great! Once things get crunchy it's assuring to know that you can probably refurbish the motor for half the price instead of having to buy a whole new one. Can't wait to start seeing these in the wild everywhere!
I think I may have to invest in one of these motors and a speed controller or two, I’ve had half cadded an overcutter that is just begging for a solution like this for it. Thanks Seth!
You briefly mentioned aerodynamic drag on the weapons in this video. That's something i rarely seen talked about in combat robotics. It doesn't seem like most teams put in much effort at all into making their weapons more aerodynamic, and instead make them worse by doing things like pocketing all the way through. I wonder if there are some "easy tricks" to reduce the total power required to keep the weapon at speed, like maybe rounding over the leading edge (not the tip, where it will contact) and sharpening the trailing edge, or taping over pockets.
Aerodynamics are complicated to accurately calculate or simulate with tools that mere mortals can access. Lots of professional fluid dynamics tools cost many thousands of dollars. I've used a couple myself but never for a spinning body so it's hard to do anything but speculate. The cubic relationship I described is one I directly measured myself though and the math checks out.
I think you should also have half sized versions of these motors, but really good job with these. It’s great we finally get motors built for a battle bot
I actually have a "half size" version of the RDY motor already in production, but it won't be ready for probably another 6 weeks. It will be about 50mm X 22mm.
Thank you! And yes mostly. The super cool exploded view render at 0:15-0:28 was something I paid someone to make for me, since I don't have access to that expensive software, but the rest I filmed and edited myself! I am blanking on the exact song used, will have to pull open the files to check.
I thought I saw a file on your workbench. Cleanliness In your work area is much desired when you’re working around magnets that like to collect all ferrous materials. You might want to mention that magnets and metal fillings are a very bad combination.
It's not like metal shavings are going to get sucked from 3 ft away into these motors. I haven't used that file on any ferromagnetic materials in a very long time anyway. I think most people have the common sense not to dump metal shavings directly onto their motor magnets
Yes and no. For a larger robot, hubmotors already exist for scooters skateboards, hoverboards, etc and I have seen them be used properly in 30lb robots and up. www.freerchobby.cc/products/mp-83mm-hub-motor-8nm-torque-for-electric-skateboard For a 3 pound robot and smaller however, there are a few significant obstacles. The lower a motor KV in a given size the less power it will output at the same voltage. So when you have a very small motor and give it a very low KV it tends to be extremely low torque and unable to move a robot without additional gearing. Unless you are running extremely high voltage - but there are extremely few ESCs on the market that fit in a 3lb robot but operate at >24V, and only a small number of builders are even running above 16V/4S in beetles right now. Unfortunately you will need a gearbox for these motors for the foreseeable future.
by any chance do you have the Cad file or 2d upper photo of the weapon for the hub motor? because it appears that the centre of the weapon has to be of that specific design (floral shape).
Looks super interesting! Would you be able to share what magnets/spec are being used in the JCR-4935/RDY-5536? Really nice to know that the magnet rings themselves are replaceable though!
The hubmotor mounts with 4X M5 threaded holes in each side, and those holes all have a machined 2mm deep 6mm diameter pocket so you can use a short thread 6mm diameter shoulder bolt to have way greater shear strength than even the already perfectly adequate M5 screws alone.
What you're doing in the combat robotics community is so awesome, and I am so glad you are finding success in it as well. I always pondered the idea of a hub motor styled like a ebike/scooter hub motor, with a deadshaft instead of a mounting surface like all the quadcopter and rc plane motors used. And well, I guess now I know how it would look :).
@@JustCuzRobotics none in stock, left email. Do you have an estimate? I am wondering should I base my new bot around the motor or not. The battle is in December but I need atleast 3 months of testing.
Would need way more info to answer thag question. What type of belt? How big of a weapon are you driving, how heavy is it, what's the weight class of the robot?
I remember racing on a wooden Snowboard with rubber strap bindings In sorrel boots with ski boot bladders inserted so I know what a game changer purpose built parts and equipment can make. I think you are heading down the right path Seth and I hope to see you in RI.😎👍
![Division V4: Hubmotor Weapon & Counter Gyro Put to the Test! [NHRL January 2024 Event Recap]](http://i.ytimg.com/vi/dg-9NFLUqR4/mqdefault.jpg)
![Division V4: Hubmotor Weapon & Counter Gyro Put to the Test! [NHRL January 2024 Event Recap]](/img/tr.png)
One thing about the RDY-5536 motor I forgot to mention: When you first spin up the motor to full speed it might draw a surprising amount of current (>10 amps) for a minute or two even with no blade on it. This seems to be from the bearing grease warming up and spreading around evenly. Once its up to speed for a couple minutes the current will drop back down to a normal ~1-3 amps at no load and it should stay that way even after the motor has cooled. You also might find some of the bearing grease has leaked out, which should not cause any problems.
Being able to buy separate magnet rings is great! Once things get crunchy it's assuring to know that you can probably refurbish the motor for half the price instead of having to buy a whole new one. Can't wait to start seeing these in the wild everywhere!
Crazy that you can buy a hub motor off the shelf. Thank you Seth!
You're very welcome!
I think I may have to invest in one of these motors and a speed controller or two, I’ve had half cadded an overcutter that is just begging for a solution like this for it. Thanks Seth!
Happy to help! I would love to see many of these over in the UK
I’m tempted to use the 4935 on an Antweight One-Spinner shuffler, like Depth Charge but more dumb and smaller
That sounds like a cool idea, but the motor alone is half a pound so it's huge for an antweight
@@JustCuzRobotics
I never said it was a good idea, I said I was tempted
You briefly mentioned aerodynamic drag on the weapons in this video. That's something i rarely seen talked about in combat robotics. It doesn't seem like most teams put in much effort at all into making their weapons more aerodynamic, and instead make them worse by doing things like pocketing all the way through. I wonder if there are some "easy tricks" to reduce the total power required to keep the weapon at speed, like maybe rounding over the leading edge (not the tip, where it will contact) and sharpening the trailing edge, or taping over pockets.
Aerodynamics are complicated to accurately calculate or simulate with tools that mere mortals can access. Lots of professional fluid dynamics tools cost many thousands of dollars. I've used a couple myself but never for a spinning body so it's hard to do anything but speculate. The cubic relationship I described is one I directly measured myself though and the math checks out.
I think you should also have half sized versions of these motors, but really good job with these. It’s great we finally get motors built for a battle bot
I actually have a "half size" version of the RDY motor already in production, but it won't be ready for probably another 6 weeks. It will be about 50mm X 22mm.
@@JustCuzRobotics will the half size ones be suitable for antweight classes?
@@JustCuzRobotics oh sweet
Did you come up and make the intro all by yourself? It's an art piece. What's the music?
Thank you! And yes mostly. The super cool exploded view render at 0:15-0:28 was something I paid someone to make for me, since I don't have access to that expensive software, but the rest I filmed and edited myself! I am blanking on the exact song used, will have to pull open the files to check.
I thought I saw a file on your workbench. Cleanliness In your work area is much desired when you’re working around magnets that like to collect all ferrous materials. You might want to mention that magnets and metal fillings are a very bad combination.
It's not like metal shavings are going to get sucked from 3 ft away into these motors. I haven't used that file on any ferromagnetic materials in a very long time anyway. I think most people have the common sense not to dump metal shavings directly onto their motor magnets
Is it possible to build something like hub motor for drive (wheels)
Yes and no.
For a larger robot, hubmotors already exist for scooters skateboards, hoverboards, etc and I have seen them be used properly in 30lb robots and up.
www.freerchobby.cc/products/mp-83mm-hub-motor-8nm-torque-for-electric-skateboard
For a 3 pound robot and smaller however, there are a few significant obstacles. The lower a motor KV in a given size the less power it will output at the same voltage. So when you have a very small motor and give it a very low KV it tends to be extremely low torque and unable to move a robot without additional gearing. Unless you are running extremely high voltage - but there are extremely few ESCs on the market that fit in a 3lb robot but operate at >24V, and only a small number of builders are even running above 16V/4S in beetles right now. Unfortunately you will need a gearbox for these motors for the foreseeable future.
by any chance do you have the Cad file or 2d upper photo of the weapon for the hub motor? because it appears that the centre of the weapon has to be of that specific design (floral shape).
The entire motor model is on GrabCAD linked on the store page
Ah, beetleweight motors, got it
Could we see any production antweight hub motors in the future?
Wait 2 weeks 😅
Looks super interesting!
Would you be able to share what magnets/spec are being used in the JCR-4935/RDY-5536?
Really nice to know that the magnet rings themselves are replaceable though!
I'll have to ask my supplier about that, I'm pretty sure they are N45 or higher
Confirmation they are N45SH grade
Any way to reduce the bolt shear forces on the hub motor?
The hubmotor mounts with 4X M5 threaded holes in each side, and those holes all have a machined 2mm deep 6mm diameter pocket so you can use a short thread 6mm diameter shoulder bolt to have way greater shear strength than even the already perfectly adequate M5 screws alone.
What you're doing in the combat robotics community is so awesome, and I am so glad you are finding success in it as well. I always pondered the idea of a hub motor styled like a ebike/scooter hub motor, with a deadshaft instead of a mounting surface like all the quadcopter and rc plane motors used. And well, I guess now I know how it would look :).
Thank you!
Thanks Seth for this information.
On the hubmotor, is it possible to have a wire pass-through the center?
No, though I'm not sure why you would want that. The shaft is solid aluminum and runs through the center.
Do you by chance have the original weapon bar CAD file for subtraction?
Yes and it's already in GrabCAD, linked in the shock absorber CAD for the 4935 motor. You can find that link on the store page.
That's cool but when subtraction recap?
Most likely next week! It's taken forever to get set up in a way I can properly film videos again so it was on hold for that time.
when can I buy some??
Check my site. It should say whether they are in stock now or allow you to sign up for email notifications when they get back in stock
@@JustCuzRobotics none in stock, left email. Do you have an estimate? I am wondering should I base my new bot around the motor or not. The battle is in December but I need atleast 3 months of testing.
I'm expecting more in late July assuming no further delays
@@JustCuzRobotics thank you man. Love your work!!!
What material would you recommend for a weapon pulley?
Would need way more info to answer thag question. What type of belt? How big of a weapon are you driving, how heavy is it, what's the weight class of the robot?
It’s a 3lb horizontal spinner, the blade is 8.6 inch by 2.6 inch out of AR500 1/4 inch thick. Timing belt for the weapon.
3d printed should work for that in Nylon or maybe even PETG or PLA Plus depending on if it might get hit or not
@@JustCuzRoboticswhat plastic would be better for the pulley that uses square nuts to attach it to the weapon?
Nylon is best but hard to print and expensive. Anything rigid should work if designed correctly.
Would these moters work for a 1 pound ant weight? If not which mothers would you recommend?
These are pretty big and heavy for a 1lb but I have some smaller versions in the works!
Ok thanks
I remember racing on a wooden Snowboard with rubber strap bindings In sorrel boots with ski boot bladders inserted so I know what a game changer purpose built parts and equipment can make. I think you are heading down the right path Seth and I hope to see you in RI.😎👍
💅✂️