RC10Talk - The Net's Largest Vintage R/C Community

Dadio wrote: ↑Thu Jan 02, 2025 1:41 pm Thanks!
You're right about that.
The design is only in my head at the moment. I was thinking about printing a hub that fastens to the back face of the ring gear.
...even thought about designing the hub to resemble a torque converter.
I'm trying to cram a motor (probably a 380 to save space) and some gear reduction into a 1:10 scale v8 engine block and automatic transmission housing. Space is very limited so using a ring gear with internal teeth places the motor and output shaft centerlines in closer proximity.

You may already know this, but if not... RC4WD sells 1:10 scale V8 engines that take 540 motors, and corresponding 10.1:1 gear ratio transmissions.

https://store.rc4wd.com/RC4WD-110-V8-Scale-Engine_p_4175.html

Lowgear wrote: ↑Thu Jan 02, 2025 6:30 pm

Dadio wrote: ↑Thu Jan 02, 2025 1:41 pm Thanks!
You're right about that.
The design is only in my head at the moment. I was thinking about printing a hub that fastens to the back face of the ring gear.
...even thought about designing the hub to resemble a torque converter.
I'm trying to cram a motor (probably a 380 to save space) and some gear reduction into a 1:10 scale v8 engine block and automatic transmission housing. Space is very limited so using a ring gear with internal teeth places the motor and output shaft centerlines in closer proximity.

You may already know this, but if not... RC4WD sells 1:10 scale V8 engines that take 540 motors, and corresponding 10.1:1 gear ratio transmissions.

https://store.rc4wd.com/RC4WD-110-V8-Scale-Engine_p_4175.html

Thanks.
Yes their all aluminum Chevy small block V8 and transmission are pretty amazing pieces.
I'm building a Ford F100 replica with a 390 but I could still use their transmission.
It doesn't need to be precise but I'd like FDR to be around 18:1. The axle I have is 2.67:1 so I'll need the transmission to be about 7:1. Again, FDR doesn't need to be precise but I don't want the truck to be fast. Okay Chevy fans, I know what you're thinking.

Built Ford tough with Chevy stuff!

But seriously that sounds really cool, and I don't believe I've seen anything done with a scale Ford engine before. I'm a bit curious to see some pics when you get that far.


To add to the list there's https://www.emachineshop.com/ as well but I don't know if they can do the gears you're after.

Lowgear wrote: ↑Fri Jan 03, 2025 12:18 am Built Ford tough with Chevy stuff!

But seriously that sounds really cool, and I don't believe I've seen anything done with a scale Ford engine before. I'm a bit curious to see some pics when you get that far.


To add to the list there's https://www.emachineshop.com/ as well but I don't know if they can do the gears you're after.

Thanks for the link.

Here's what I've found on ebay. With shipping and tax, it's around $10 so easily fits my budget.
https://www.ebay.com/itm/266338963752?_skw=mini+planetary+gear+set&itmmeta=01JGN0HXHFDPNY1CQ95824ZE8S&hash=item3e030a1128:g:JA8AAOSwO71ktkbk&itmprp=enc%3AAQAJAAAA0HoV3kP08IDx%2BKZ9MfhVJKlq%2BLZtR0QX4QdC4Y38KdaGtef7EC5DFRmXApTIyyzdA9PoQ9URWq%2FT3JnHUUIa%2FzsYp1jTFv7SNq5Qx9PnubsS8LItOKv8nr5hEr6h3iZdawtPGKxDtHfNabWlhbLNxFJOTdxa0WxKoXr0vYDwij74H1G2vQz7uClp%2BIIc0LE%2BEci5Ife57jN97Z%2BQMMGSPPaXgbirXIbYdBzCbq6eEpmtHTnDPAIgAIKe5h7TLOApdVhFADtoosgWOfUmJou9btM%3D%7Ctkp%3ABk9SR-rYx6CFZQ


At 22mm diameter, it's very small and will fit within the bell housing. The description tell us that total gear reduction is 45:1 ratio but that long case suggests that ratio is achieved with two or more planetary sets.

If it uses only two sets, then the ratio of each will be 6.7:1 and that's perfect for my build (6.7 x 2.67 = 17.9). I should be able to cut the case in half and use only one gear set.
Not sure if I will use the included motor or swap it for a 380 - I'll test it when it arrives.

Anyway, here's the "engine" I'm working with. It's pretty close to an actual Ford FE (big block) and only requires some minor tweaking.

Well, the stepper motor finally arrive and the autopsy revealed a 3-stage planetary set. Each gear set is 3.56:1 (the cube root of 45.2) so I've gone ahead and modified the transmission to use only one gear set:

I needed to turn an input shaft, make a bearing carrier and a motor plate. The bearing carrier is printed because I didn't have metal bar stock large enough to turn this part.
Anyway, I'm using a 14 tooth motor pinion and 28 tooth spur gear for a 2:1 primary gear ratio. This will yield a 19:1 FDR (2 x 3.56 x 2.67) - perfect for my application.
I wasn't able to use the include stepper motor so I'm using a brushed Tamiya 380 motor instead.
It's close but everything fits inside the 1:10 scale C6 case and FE engine block.
It's just a work truck so I'm running a 2-barrel carb.

That's awesome!

that's awesome!!!! perfect!!

Lowgear wrote: ↑Mon Feb 03, 2025 1:18 pm That's awesome!

Thank you sir.
The unit included steel gears and the mods were easy so I'll be using this method again on my next build:

jwscab wrote: ↑Mon Feb 03, 2025 1:23 pm that's awesome!!!! perfect!!

High praise indeed from an accomplished engineer and metal working master.


Thank you Joe.

I thought you might like this.

That's the best part of the hobby to me!! A bunch of like minded people making stuff and building stuff