Experimenting with brushless out runners and planetary gear reduction units

[Das Boot]

Here is a still of my HM smoke unit. Works well.

[SubDude]

My experience with this particular unit has been very similar to yours. The reason the smoke is more visible in this photo is due to the way the sun light is illuminating it. The smoke is barely visible most of the time. This may be a result of the type of “smoke juice” that is recommended to be used with these units.

After my initial running of the unit and being similarly underwhelmed with the visibility and the volume of the smoke produced, I did some searching for information on other smoke generators. Found quite a bit of write ups on how to build them from scratch and the different types of fluids to use in them. They’re very simple and very low cost to build and I will be doing just that next time.

The different types of fluids which can be used to produce the smoke effect have a range of performance as well as a range of pros and cons with each type. One example of a fluid option I’ve read about is using a glycerin based fluid such as bakers glycerin, which supposedly produces better volumes of smoke. (Glycerin is one of the base ingredients in e-cigarette fluids) The downside to glycerin is that it eventually gums up the works and requires more maintenance to the units.

I suspect the smoke fluid used in the Harbor Models units are the low to zero maintenance type fluids that also produce less smoke. The instructions that come with the unit say using any other fluid will void the warranty. Then another paragraph down in the instructions, towards the bottom of the page, it also states that there is no warranty….

Ok, so maybe it isn't just me...I too have watched some videos about DIY electric smoke generarors. I would like to come up with something better for my Fletcher.

[Monahan Steam Models]

I have one of those exact units in my Fletcher and I cannot get it to put out enough smoke to be visible. I was a little disappointed with it but maybe I am doing something wrong.

My experience with this particular unit has been very similar to yours. The reason the smoke is more visible in this photo is due to the way the sun light is illuminating it. The smoke is barely visible most of the time. This may be a result of the type of “smoke juice” that is recommended to be used with these units.

After my initial running of the unit and being similarly underwhelmed with the visibility and the volume of the smoke produced, I did some searching for information on other smoke generators. Found quite a bit of write ups on how to build them from scratch and the different types of fluids to use in them. They’re very simple and very low cost to build and I will be doing just that next time.

The different types of fluids which can be used to produce the smoke effect have a range of performance as well as a range of pros and cons with each type. One example of a fluid option I’ve read about is using a glycerin based fluid such as bakers glycerin, which supposedly produces better volumes of smoke. (Glycerin is one of the base ingredients in e-cigarette fluids) The downside to glycerin is that it eventually gums up the works and requires more maintenance to the units.

I suspect the smoke fluid used in the Harbor Models units are the low to zero maintenance type fluids that also produce less smoke. The instructions that come with the unit say using any other fluid will void the warranty. Then another paragraph down in the instructions, towards the bottom of the page, it also states that there is no warranty….

[SubDude]

Thanks Steve. It’s a small 6 volt commercially available smoke unit from Harbor Models out of Southern California.


The black box unit on the left is the smoke generator. The electronic components on the right provide power and control of the smoke generator.

I have one of those exact units in my Fletcher and I cannot get it to put out enough smoke to be visible. I was a little disappointed with it but maybe I am doing something wrong.

[Monahan Steam Models]

Looks good Nick. What are you using to produce the smoke?

Thanks Steve. It’s a small 6 volt commercially available smoke unit from Harbor Models out of Southern California.


The black box unit on the left is the smoke generator. The electronic components on the right provide power and control of the smoke generator.

[SubDude]

After probably 20+ years of sitting on the shelf with it’s running gear removed and waiting for a upgraded refit, the harbor tug finally sails again. The 1400kv 1806 brushless motor coupled to the 22mm 4.75:1 planetary gear reduction runs very well with the 8000mah 7.4 2s LiPo pack. Lots of fine rpm adjustment down low and not overly too much top speed at full throttle when needed for emergency maneuvers.

Looks good Nick. What are you using to produce the smoke?

[Monahan Steam Models]

After probably 20+ years of sitting on the shelf with it’s running gear removed and waiting for a upgraded refit, the harbor tug finally sails again. The 1400kv 1806 brushless motor coupled to the 22mm 4.75:1 planetary gear reduction runs very well with the 8000mah 7.4 2s LiPo pack. Lots of fine rpm adjustment down low and not overly too much top speed at full throttle when needed for emergency maneuvers.

[Monahan Steam Models]

Good find Tom! Thank you

[trout]

Check out these: https://mpjet.com/shop/gb/882-planetary-gearboxes

[SubDude]

The good news is that center to center hole spacing and the M3 or the M4 threads is a standard mounting pattern of 540, 550 and 600 brushed motors. Any planetary gear unit that is designed to bolt up to those types of motors should bolt up to your brushless. For example, the larger of the two planetary gear units that I posted at the beginning of this thread is just one of many that share that standard mounting pattern. There are much better units out there though.

The tricky part is the 5mm output shaft on your brushless motor. Most brushed 540, 550 and 600 motors have a 3.175mm (.125”) output shaft. I spent a small amount of time today searching for planetary unit that may have a pinion gear that would accept a 5mm shaft or one with a pinion at least large enough that it could be bored out to fit onto a 5mm shaft. I did find a number of promising candidates but I wasn’t able to finish the research today.

Another option you and I discussed this morning was to turn the reduction unit into a standalone component by creating a pinion gear shaft carrier part and bolting that to the motor mount side of the planetary gear unit and using a coupler to connect to the brushless motor.

Either way there seems to be potential options to make this happen. Will keep digging in the meantime to see what’s out there.

Excellent news Nick! Thank you for taking the time to look into this. I would prefer an off the shelf option to designing and printing something and I could likely modify something suitable if needed to make a stand alone unit. That is a good idea.

[Monahan Steam Models]

Yeah, the specs on the motor are not that great. Hole spacing center to center is 25mm. M3 and M4 threads. Not sure about a reduction ratio.

The good news is that center to center hole spacing and the M3 or the M4 threads is a standard mounting pattern of 540, 550 and 600 brushed motors. Any planetary gear unit that is designed to bolt up to those types of motors should bolt up to your brushless. For example, the larger of the two planetary gear units that I posted at the beginning of this thread is just one of many that share that standard mounting pattern. There are much better units out there though.

The tricky part is the 5mm output shaft on your brushless motor. Most brushed 540, 550 and 600 motors have a 3.175mm (.125”) output shaft. I spent a small amount of time today searching for planetary unit that may have a pinion gear that would accept a 5mm shaft or one with a pinion at least large enough that it could be bored out to fit onto a 5mm shaft. I did find a number of promising candidates but I wasn’t able to finish the research today.

Another option you and I discussed this morning was to turn the reduction unit into a standalone component by creating a pinion gear shaft carrier part and bolting that to the motor mount side of the planetary gear unit and using a coupler to connect to the brushless motor.

Either way there seems to be potential options to make this happen. Will keep digging in the meantime to see what’s out there.

[Subculture]

Yes, but they're not oil impregnated, and water acts as a lubricant. Perfect for use in the drink. there are alternatives if you have trouble finding them. Norbert Bruggen sells them in quite a few sizes, but postage may be costly to the US.

Lead teflon bearings are another similar item.

[He Who Shall Not Be Named]

To be specific, you'd want DU-B. https://www.ggbearings.com/en/why-ch...re-du-bearings

A form of 'Oilite' bearing?

David

[Subculture]

Please pardon my ignorance but what are DU bearings?

To be specific, you'd want DU-B. https://www.ggbearings.com/en/why-ch...re-du-bearings

[SubDude]

Steve,

Could you measure the threaded mounting hole spacing on the face of the motor and let me know the thread size? I could not find those details on Mtroniks website. I’ve been looking at various planetary gearboxes this morning. Did you have a rough idea of what sort of reduction ratio you would prefer?

Yeah, the specs on the motor are not that great. Hole spacing center to center is 25mm. M3 and M4 threads. Not sure about a reduction ratio.