25 replies to this topic

[Quack]

After taking the advice of the community in my previous topic (link for those who want to see), I ordered a pair of brushless motors the equivalent in speed to a stock Nerf blaster. Here are my findings. 

 

1. Brushless motors are expensive

I probably bought some of the cheapest motors I could probably buy, however, if I was going to do this again, I would probably buy ones that are a little bit more powerful. The problem with brushless motors is that you cant just buy the motors and be done with it. You also need ESC's and a servo tester to run your setup. While My ESC's were already coded, you may even want to buy a programming card so you can add this like electronic braking if you want (more on that later).

2. Lipos or other rc batteries are a necessity

Brushless motors are meant to work off of Lipo batteries. The product description should tell you which one. That means, in order to use brushless motors, you must have a lipo battery and a charger at least (battery alarm recommended). You can use other battery chemistries, but you might have to figure out the power equivalent yourself.

3. ESC's are a cool Idea for nerf

Because ESC's are programmable you can have your motors do all sorts of things. Perhaps most useful to nerf is electronic braking. Forget complicated circuitry, with an ESC you have the ability to have electronic braking built right in.

4. Inrunner vs. Outrunner motors

There are two main types of brushless motors, Inrunner and Outrunner. Inrunner motors act similarly to regular brushed motors in that only the shaft spins. However these tend to overheat easier and need to have flywheels attached to work in Nerf blasters. Outrunner motors on the other hand act a little different to regular brushed motors. Instead, the outer bell of the motor turns while the inside stays stationary (the bottom of the motor mounts to whatever the motor is being placed on). These motors are great because they act as their own flywheels. On top of that, they have more torque because the outside is spinning and they run cooler. The motors I bought were outrunners.

5. Wiring

Brushless motors require a lot of wiring. None of the wiring is that difficult, however there are a couple things you have to keep in mind. First, you may have to wire battery connectors. My ESC's came with leads to connect to my battery, but I had to wire the connectors themselves. On top of that, I had to wire the harness to split the battery so that both motors ran off the one battery, it was a lot more solodering and shrink wrap than your basic stryfe mod.

6. Sound

My brushless motors are very quiet. I don't know how much sound level increases as the power does, But my motors only change in pitch when they are "revved" up.

 

Overall I think brushless motors are for those who really want to go all out in a flywheel mod. They are especially helpful for rivals rounds so that is where they might shine, but they only other reason you would need such torque was if your flywheels were metal (assuming you're going to use an inrunner motor). While Brushless motors may have the option of electronic braking, they will also require massive shell modification. Perhaps they are most useful in flywheel homemades like the one I am building. I don't really want to put down how to wire them up, but if enough people are interested, I guess I could try my best.

 

Here is my setup.

Edited by Quack, 27 January 2016 - 05:01 PM.

[shandsgator8]

Thanks for sharing! What is the advantage of braking within the context of flywheel Nerf blasters?

[Quack]

Thanks for sharing! What is the advantage of braking within the context of flywheel Nerf blasters?

Electronic braking on flywheel blasters stops the flywheels as soon as you let go of the rev switch. People tend to like it because it quiets the blaster down instantly after the rev trigger is depressed. 

[shandsgator8]

That makes sense...I guess. To each their own. Would ESC controlled electronic braking be beneficial for pusher motors?

[xXD3V1LXx]

Yes shand, and in fact it would be amazing if you could program esc's to rotate X times, you get set up burst fire single fire and full auto.

[Quack]

Yes shand, and in fact it would be amazing if you could program esc's to rotate X times, you get set up burst fire single fire and full auto.

I'm not sure if they could be programmed to that degree, but with a brushless motor on your pusher mech you might be able to simplify the wiring slightly.

[DjOnslaught]

I think the electronics needed to use the esc to create a select fire method requires a bit more in depth wiring and a total controller like a arduino

[Quack]

I think the electronics needed to use the esc to create a select fire method requires a bit more in depth wiring and a total controller like a arduino

The only benefits I see ESC's having to nerf is the possible use of electronic braking and possibly making it so that the motors are always spinning at a low rpm to reduce flywheel spin up times.

[DjOnslaught]

The only benefits I see ESC's having to nerf is the possible use of electronic braking and possibly making it so that the motors are always spinning at a low rpm to reduce flywheel spin up times.

Having the motors constantly spin at low rpm to reduce rev time is one of those things that all flywheel blasters should have as a feature.

[shandsgator8]

Having the motors constantly spin at low rpm to reduce rev time is one of those things that all flywheel blasters should have as a feature.

 

And perhaps brushless technology makes it feasible (from a sound and efficiency standpoint)

[DjOnslaught]

 
And perhaps brushless technology makes it feasible (from a sound and efficiency standpoint)

Definitely likely from a sound perspective, not familiar enough with the innards of them to know efficiency or lifespan of them.

[Remzak]

The lifespan of a brushless motor is insane. Even cheap ones have nice bearings, and brushes cannot be worn down. (Because there are none) the only damage I have ever sustained are bent shafts and tossed magnets, both of which can be fixed/replaced. The main detractor is the cost of the motors and speed controls. In my tests the efficiency of a decent motor can reach 80-85%.

Edited by Remzak, 28 January 2016 - 12:04 PM.

[jwasko]

Great job following through on this. It looks like you have the motors mounted already...have you tried shoving any darts through them?

 

Two questions for clarification:

What makes you think that more powerful ones may be needed?

 

You want to look into "idling" the motors...How fast do they take to go from zero to full speed? The best brushed motors (with good batteries and wiring) can shoot a dart at near full velocity quite quickly (example). Do these motors rev like that, or is it closer to a full second or more?

 

Side note: What's the C-rating on that battery? The picture is to small for me to read.

Edited by jwasko, 28 January 2016 - 12:32 PM.

[Quack]

Great job following through on this. It looks like you have the motors mounted already...have you tried shoving any darts through them?

 

Two questions for clarification:

What makes you think that more powerful ones may be needed?

 

You want to look into "idling" the motors...How fast do they take to go from zero to full speed? The best brushed motors (with good batteries and wiring) can shoot a dart at near full velocity quite quickly (example). Do these motors rev like that, or is it closer to a full second or more?

 

Side note: What's the C-rating on that battery? The picture is to small for me to read.

My motors are only 1000 kv so I'm only getting about 11,000 rpm. I just bought some 3800 kv motors so I can get about 41800 rpm. Right now putting some HIR's through I'm getting about 30 feet (I don't have a chronograph yet), and about 20 feet with darts (motor spacing is for HIR's with 11mm of compression). 

In terms of motor spin up time, my motors spin up to full speed as fast as I can twist the potentiometer on the servo tester. I assume less than a second. Keeping the flywheels at low rev all the time might only help very slightly.

I am using a 25c battery because the ESC's are rated to 30 amps. I guess I could use a 30c because the ESC's can handle 40 amp bursts but I thought I'd play it safe. Here is a link.

[Langley]

And perhaps brushless technology makes it feasible (from a sound and efficiency standpoint)

I think it's totally feasible to keep brushed DC motors idling to reduce spin-up with a simple motor controller, but I assume it would put a lot of wear on them.

[shandsgator8]

I think it's totally feasible to keep brushed DC motors idling to reduce spin-up with a simple motor controller, but I assume it would put a lot of wear on them.

 

It would, and absolutely kill your battery life and increase the complexity of the wiring setup, compared to a direct-to-battery brushed motor setup.

 

Remzak is correct about brushless motors being very efficient, probably by at least a factor of 5 (I think I remember hearing that brushed motors were about 5-15% efficient while brushless were 75-90%), depending on the setup. And except for the bearings they're practically immortal, as long as you use them as designed.

Edited by shandsgator8, 28 January 2016 - 03:21 PM.

[Remzak]

I did almost the same as you, but I put it on to a PVC frame with a blowgun, just a proof of concept for now. It's ugly as heck, I created a monster, but ranges are fifty feet flat with random relatively low rpm motors and it took 15 minutes. I even used mismatched motors for added swag. I used a remote control car remote because I couldn't find my servo tester. It's just horrible. The motors don't slow down though, and you can even rev the motors with a dart in the middle, even with tight flywheel spacing. I already scrapped this, by the way. Expect a more polished homemade flywheel design and write up from me by Tuesday.

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Edited by Remzak, 28 January 2016 - 10:52 PM.

[Agles]

Remzak, i see your using just the outside of the motor. any thought as to adding something for more grip? 

[Remzak]

As I said, this took 15 minutes, and was just for me to do a preliminary test. I will add electrical tape to the outside of the bells in my next proof of concept.

[Quack]

As I said, this took 15 minutes, and was just for me to do a preliminary test. I will add electrical tape to the outside of the bells in my next proof of concept.

I added etape o the outside of my motors. It significantly improved grip as opposed to smooth metal.

[Remzak]

To save the cost of brushless equipment I have a solution. You can use two motors with one ESC. As long as you pick a properly rated ESC most motors can be used with one ESC simultaneously with an equivalent motor. I used this in my second brushless motor setup.

[Quack]

To save the cost of brushless equipment I have a solution. You can use two motors with one ESC. As long as you pick a properly rated ESC most motors can be used with one ESC simultaneously with an equivalent motor. I used this in my second brushless motor setup.image.jpg

Perfect. I was reading up on that and I couldn't get conclusive results. My new motors are still shipping, i'll be sure to post some results when I wire them up. What motors are you running.

Edited by Quack, 02 February 2016 - 10:31 PM.

[Remzak]

I am using DYS 1806 2300kv. They are smaller motors. I had some lying around though, and performance is fantastic. I do not recommend them because they are very challenging to mount.

Edited by Remzak, 03 February 2016 - 06:59 AM.

[Foammunition]

Electronic braking on flywheel blasters stops the flywheels as soon as you let go of the rev switch. People tend to like it because it quiets the blaster down instantly after the rev trigger is depressed. 

Is this such an issue considering the declared quietness of the brushless motors?

[Quack]

Is this such an issue considering the declared quietness of the brushless motors?

While brushless motors are quiet, they are not silent. If you wanted to be "super stealth" it could be very helpful.