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Oil filled gearbox

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19 minutes ago, Collin said:

Guys, go back to brushed if you miss maintenance. :lol:

Oh, I had never stopped using brushed. Is that a problem I am not aware of? 

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So I've dabbled with this idea. Running a DF-02 with a big 3 cell LiPo, 4000Kv motor, and TT-01 speed gears, the gears were rotating so fast they were throwing all the grease off, and then I'm doing 50mph on dry gears.... (I actually melted the plastic washer that clips over the main spur gear doing this. So, as the gearbox is split horizontally, I used 3 in 1 to put a small sump of oil in the front and rear diff housings. After a run, the gears at least still had oil on them. I'd didn't attempt to seal the drive cups, just kept the car more or less horizontal and then checked the oil after each run (You can see it's leaked out after a run). 

Th only other machine  I tried it on was my TXT-1, which has a natural sump moulded into the axle. To seal the area, I just put thick axle grease outboard of the inner axle bearings (That support the diff). This provided a good seal so the oil would not wash through the bearings, and with the slow rotational speed of the axles it didn't blow the thick grease everywhere. Using a bit of silicone sealant on the top cover stopped nearly all the leaks coming out. However, sealing up gearboxes is a pain in the neck every time you want to do maintenance, so I went back to using grease instead.

So in summary, the only time I'd use oil now, was if something was rotating so quickly the grease won't stay on the gears.

But don't let that stop you from trying .... :)

PS Thinking back I did oil my sand rover gears. I think that was because that was what my Dad had available, the only upside I can think of with open gears is that grit is less likely to stick oil than grease, but in hindsight, the best option with the 380 would have been to run it with no grease at all.

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8 hours ago, alvinlwh said:

Oh, I had never stopped using brushed. Is that a problem I am not aware of? 

No, all fine. Just some people mentioned that brushless is the answer because no more maintenance.

 

7 hours ago, MadInventor said:

So I've dabbled with this idea. Running a DF-02 with a big 3 cell LiPo, 4000Kv motor, and TT-01 speed gears, the gears were rotating so fast they were throwing all the grease off, and then I'm doing 50mph on dry gears.... (I actually melted the plastic washer that clips over the main spur gear doing this. So, as the gearbox is split horizontally, I used 3 in 1 to put a small sump of oil in the front and rear diff housings. After a run, the gears at least still had oil on them. I'd didn't attempt to seal the drive cups, just kept the car more or less horizontal and then checked the oil after each run (You can see it's leaked out after a run). 

Th only other machine  I tried it on was my TXT-1, which has a natural sump moulded into the axle. To seal the area, I just put thick axle grease outboard of the inner axle bearings (That support the diff). This provided a good seal so the oil would not wash through the bearings, and with the slow rotational speed of the axles it didn't blow the thick grease everywhere. Using a bit of silicone sealant on the top cover stopped nearly all the leaks coming out. However, sealing up gearboxes is a pain in the neck every time you want to do maintenance, so I went back to using grease instead.

So in summary, the only time I'd use oil now, was if something was rotating so quickly the grease won't stay on the gears.

But don't let that stop you from trying .... :)

PS Thinking back I did oil my sand rover gears. I think that was because that was what my Dad had available, the only upside I can think of with open gears is that grit is less likely to stick oil than grease, but in hindsight, the best option with the 380 would have been to run it with no grease at all.

In my case I am not shure if I can make the gearbox oil tight also. Its a fast buggy and bearings/outdrives can keep the oil. It would need groves for o-rings on the shaft of the outdrives where the bearing sits on. As more I think about, it is a nice gimmick but not really practical.

I never run 3S and I am so shure 2S is fair enough for our Tamiyas (at least most of them) but I luckily had always some grease on the gears when I made maintenance on the gearbox.

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As long as you are not dealing with metal on metal gears, there's really no need for oil / grease in the transmission of our little toy cars at all. Even the much higher powered racing RC cars (even in open modified classes) all run dry - and they run just fine, BTW.  Please don't fall into that mental trap where you start comparing your big 1:1 cars with your models. Both (usually) have 4 wheels, but that's almost where the similarities end. Believe me, I have seen and heard so many things that absolutely need/should be done, or the opposite, never to be even thought of, by people who (at least claimed to) know a lot about real cars, but obviously had zero experience/knowledge about RC models and their quirks. :) It's really two different worlds we're talking about there.

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49 minutes ago, hIghQ said:

As long as you are not dealing with metal on metal gears, there's really no need for oil / grease in the transmission of our little toy cars at all. Even the much higher powered racing RC cars (even in open modified classes) all run dry - and they run just fine, BTW.  Please don't fall into that mental trap where you start comparing your big 1:1 cars with your models. Both (usually) have 4 wheels, but that's almost where the similarities end. Believe me, I have seen and heard so many things that absolutely need/should be done, or the opposite, never to be even thought of, by people who (at least claimed to) know a lot about real cars, but obviously had zero experience/knowledge about RC models and their quirks. :) It's really two different worlds we're talking about there.

Totally agree with you. What is common between 1:1 and "toycars" is physics.

Steering and suspension geometry is almost the same as far I understand.

But on gears, clutches and the working load, yes, its different.

How about aluminum on plastics? People often argue spur gears (plastic) are eating aluminum pinion gears. I use aluminum anodized and steel, cant see a difference.

How about fir example Trf201, who has aluminum first gear on the msin shaft, working into plastic gear next befor diff?

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12 minutes ago, Collin said:

Totally agree with you. What is common between 1:1 and "toycars" is physics.

Steering and suspension geometry is almost the same as far I understand.

But on gears, clutches and the working load, yes, its different.

How about aluminum on plastics? People often argue spur gears (plastic) are eating aluminum pinion gears. I use aluminum anodized and steel, cant see a difference.

How about fir example Trf201, who has aluminum first gear on the msin shaft, working into plastic gear next befor diff?

While physics of course don't change as such, but they also don't quite scale. ;) Best example: aerodynamics.

On the topic of aluminium, it depends on the type and treatment. Good and hardened aluminium should not be a problem. Softer alloys may experience severe problems. So the answer is the most dreaded of all: "it depends".

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On 10/15/2021 at 2:16 PM, Mokei Kagaku said:

As a sidenote, Kyosho used to lead the exhaust through the gearbox on some early models. Quite clever as it both reduced the engine noise and provided lubrication to the gearbox. Don't think it was much of a benefit, but I like the idea a lot.

Love this. My kind of interesting fact B)

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