geared motor

[rc4ever]

Could anyone tell me what is the best rpm output speed geared motor?
thanks,
Leon

[Espeefan]

It's all dependent on your model's wheel diameter is, the voltage you want to run, and what kind of scale speed you are after! It's really hard to just suggest the right motor, without knowing all these other factors. Usually something around 20-35 RPM at max voltage gives you a decent scale speed, with a 6" tall tire. Or about 1.6 actual miles per hour, on the high end. 16 scale miles per hour, on a 1/10 scale model. Or 22 scale miles per hour on a 1/14 scale model, which is fast for a loader. It's all in the math.

[rc4ever]

Thanks espeefan for the wonderful answer!! I've recently bought the geared motor with 5rpm output speed on ebay (I didn't pay attention for the rpm output speed, my fault) It's very powerful but way too slow! :-( I'm planning to buy another one but unsure about the proper rpm output speed, that's why I asked for a suggestion? If u take a look the pics of my dump truck "construction equipment- rc adt dump truck" and let me know what rpm should I go for?
Thanks again!
Leon

[Lil Giants]

Your info is still a bit vague..

Are you still using the RC4WD trans? If so, what's the reduction of it? Or are you connecting a gearhead motor direct to your 1st axle? What's the ratio of your axles? What's the diameter of your tires?

Using my knowledge of the wdc 740 as an example..
motor 5000rpm
trans in 2nd gear, 11:1 reduction
axles reduction 15:1
tire diameter 122mm

5000/11/15= approx 30 rpm @the wheel center

I was looking thru your photos of your ADT project, you've got a serious problem with your hinge joint & how/where your universal joint is connected. A sharp turn left is going to put that universal joint beyond it's capable angle of operation & wear out quickly or even lock it up all together.

I would suggest you remake your hinge point so your universal joint is directly below center of your hinge pins and your driveshaft going forward to the front prop shaft is fixed to the front body half. It would also improve longevity of that shaft's fixed centering point if it were bearing'd on two points of contact.

Does that make sense?

Pic of 740 hinge

[rc4ever]

compare



Thanks Lil Giants for taking a look at the pics and tell me the problem about the hinge point. I noticed there was something wrong too before I read your message. I did remarked it and it works whole lot of better. I like to show y'all the geared motor that I bought n this is what I want to connect it to the 1st axle. I think it looks better too!! The dia of the tires r almost 5.5" n the Final drive ratio 3.75:1 of the axle (from rc4wd n I have no idea what the number means) So, Do you think the 30rpm will work?
Thanks,
Leon

[Lil Giants]

So the motor you have pictured is 10RPM? Multiply 3.75 axle ratio = 37.5RPM

2nd gear was a little slow on the junk 740, so maybe you got it right with a bit faster ratio & .7 inch taller tire. Those tires RC4WD too? (I would assume so) very thin side walls, the tires will squat alot without packing adding.

The hinge looks much better, how well it will work will depend on how sharp you turn. Perhaps with your front axle so far ahead of the hinge, you won't need to many degrees angle to turn sharply.

[rc4ever]

Thanks lilgiants,
So, do u think the 40rpm output speed geared motor will work? About the tires I have no luck to find a better n harder foam to handle the weight! Do u have any suggestion?

[RCP57]

Wouldn't a 10 rpm gear motor driving an axle with a 3.75-1 gear ratio give you an output of about 2.6rpm?

I purchased some foam from an automotive upolstry shop and made my own inserts with it. It looks a little like carpet underlay but it's 2 inches thick. It works out great in my Euclid. I can haul a car battery in the box now and the tires stay put with no glue but it still has a little give for traction while empty. I can take a picture of the foam for you if you like.

Reg

[rc4ever]

Thanks reg, I'm more than happy to c the pic of the foam! please post it n tell me where to buy it? About the geared motor, what do u recommend? I've seen many of them on eBay but unsure which one I should go for
Thanks in advance
Leon

[Lil Giants]

Originally Posted by RCP57

Wouldn't a 10 rpm gear motor driving an axle with a 3.75-1 gear ratio give you an output of about 2.6rpm?

Reg

You're right! I don't know what I was thinking?! I should have divided, not multiply.

You'd need atleast 120rpm to achieve 32rpm wheel speed... 140rpm would be just over 37rpm.

[RCP57]

Here are the pics of the foam that I bought. It cost me $15 for this piece so it's not that expensive. I used a bandsaw to cut the outside and a razor blade for the inside.

I think Joe is right about the rpm of the gear motor you need. Personally I wouldn't buy anything that was over 200rpm or it will be pretty fast. My skidder for example has 152rpm motors with a 2.6-1 axle and 7 3/4" tall tires and the speed it quite good.

Reg

[rc4ever]

thanks for the pics!!! I'll give it a try.... where did you buy it, Reg?

[RCP57]

I bought it from a local automotive upholstery shop. They use it to bolster seats.

[rc4ever]

So far I've already bought 2 geared motors from ebay: 1st with 10rpm and 2nd with 40rmp... neither of them work so could anyone give me an idea of buying the right rpm motor from ebay, please?
Thanks y'all!!!

[Lil Giants]

Reply #10

[rc4ever]

lol I didn't pay enough attention to your previous message.... don't yell at me