Lixander`s lodge - W.I.P.`s and MOC`s

[pleegwat]

1 hour ago, Lixander said:

3300 kV

3.3 megavolts?

[Zerobricks]

My recommendation is to drive the wheels as directly as possible.

[Lixander]

9 hours ago, Zerobricks said:

My recommendation is to drive the wheels as directly as possible.

I will try it. Thanks for the advice!

9 hours ago, pleegwat said:

3.3 megavolts?

Well, yes.

[Lixander]

I tried other gear set-ups and this is the only one that works. It has the ratio 1:1, but due to the half-stud 12 tooth gear, it wouldn`t last too long for sure.

If you have any advice or idea on the gear set-up, I will gladly test it.

Also, I found out that a worm gear set-up also works (at least in theory), but I am not sure how long it will last.

Edited May 8, 2024 by Lixander

[Ryokeen]

Worm gears have siginificant friction under load but more important here is, you loose all ability to free roll. Means as soon as you let go of the throttle the wheels stop.

From my experience(unless it's very small 12t gears) gears get damaged because the axle holes on the supporting lifarms wear out. That increases the play and missalignes the gears disturbing the meshing.
Besides 3300kv even on 2s is a lot of rpm. Considering that and similiar setup as the 20tooth and 12tooth gear with only 2 buggy motors already had axles melting for me, the 24000 rpm(2s LiPo) will always cause problems.

[Lixander]

On 5/8/2024 at 10:06 PM, Ryokeen said:

Worm gears have siginificant friction under load but more important here is, you loose all ability to free roll. Means as soon as you let go of the throttle the wheels stop.

From my experience(unless it's very small 12t gears) gears get damaged because the axle holes on the supporting lifarms wear out. That increases the play and missalignes the gears disturbing the meshing.
Besides 3300kv even on 2s is a lot of rpm. Considering that and similiar setup as the 20tooth and 12tooth gear with only 2 buggy motors already had axles melting for me, the 24000 rpm(2s LiPo) will always cause problems.

I see. Thanks!

I will search for other gear set-ups in the next days then.

Edited May 10, 2024 by Lixander

[Lixander]

Until i actually get the parts to finish the RC mod of my own retro buggy, I saw an opportunity to try to use the RC set-up in someone else`s design........no surprise that it is another retro themed buggy.

Namely Apachaihapachai`s Sprite retro buggy. Nice design @apachaihapachai ! I will put the photos on the page of the MOC in a few days.

Same as at my own buggy, I need some other opinions, maybe even some advices about the gear set-up. What do you think? The gears will last?

Edited May 12, 2024 by Lixander

[Lixander]

It worked!

With a gearing consisting of 2x pairs of 12 toothed coupled to 20 toothed gears (in this very order; the final gear ratio is 2,79:1) the model works fine, just the gears skid a little when the motor starts running.

But this time, I had problems with the axle adapter because it wasn't aligned properly on the motor shaft and it got shredded. Also, due to this, an axle melt but the gears and the other axles seem to be fine.

Despite that, I managed to run the buggy for a maximum of 5 minutes and I got a speed of 11,50 km/h / 7.15 mph in a park.

I will test the buggy furthermore in the days that would come.

Edited May 15, 2024 by Lixander

[Ryokeen]

@Lixander What shaft diameter does that motor got ? You might look into mod(ule) 1.0 pinion gears. They are available at least for 3.2/3.175mm and 5mm and could solve your problem with having to use an axle adapter, as it's kinda hard to center the connection properly. If the motor is properly secured and as i see you can 3D print parts so that should be easy to do, that could work aswell. I do that on my cars with a mod 1.0 12t gear which is exactly the same size as an lego 12t gear and never had skipping gears.

[Lixander]

The shaft diameter is 3.175 mm.

I will also search for that pinion gear.

But do you use that pinion with other plastic gears?

And thanks for the recommendations!

Edited May 16, 2024 by Lixander

[Ryokeen]

Yes currently i use it with a 36t plastic gear, or well 2 gears a bit sanded down and glued together with resin so have more contact area. Together with either dry fluid or a few drops of silicon oil works qute well. After 4h of driving with very sudden acceleration and breaking i couldn't find any wear.
You should try to either use dry fluid or any lube that is suited for outdoor use like chain lube if you can't enclose the gears. Silicon Oil+dust and dirt will turn into grinding paste :D
 

[NoEXIST]

I think portal hubs won't like this amount of spinning:) I also would try go into a bigger reduction. RC cars usually have something near 9:1 with these classes of motors. It probably will perform even better!

[Lixander]

21 hours ago, Ryokeen said:

Yes currently i use it with a 36t plastic gear, or well 2 gears a bit sanded down and glued together with resin so have more contact area. Together with either dry fluid or a few drops of silicon oil works qute well. After 4h of driving with very sudden acceleration and breaking i couldn't find any wear.
You should try to either use dry fluid or any lube that is suited for outdoor use like chain lube if you can't enclose the gears. Silicon Oil+dust and dirt will turn into grinding paste :D
 

Oke, thanks!
Yeah, I would had lubricate the gears but going outside without an enclosed gearing and made from plastic, is pretty hard to find something that will work :/

18 hours ago, NoEXIST said:

I think portal hubs won't like this amount of spinning:) I also would try go into a bigger reduction. RC cars usually have something near 9:1 with these classes of motors. It probably will perform even better!

Well, the portal wheel-hubs had no visible problem until now. I will also see what I will do with the gearing.

For now I have trouble finding a reliable axle adapter and also the motor seems to fluctuate its RPM even if the throttle is at the same level.

Edited May 17, 2024 by Lixander

[NoEXIST]

1 hour ago, Lixander said:

For now I have trouble finding a reliable axle adapter and also the motor seems to fluctuate its RPM even if the throttle is at the same level.

Floating rpms is probably the result of small reduction. Also bearings definitely will lower the load on the motor.

Also about a gear and adapter. I personally like the idea of having an rc spur meshed with Lego gears. Might work better than an adapter

[Lixander]

1 hour ago, NoEXIST said:

Floating rpms is probably the result of small reduction. Also bearings definitely will lower the load on the motor.

Also about a gear and adapter. I personally like the idea of having an rc spur meshed with Lego gears. Might work better than an adapter

I already changed the first gear assembly with 8 to 24 toothed gears. I will also check the settings on the ESC when my battery will be fully charged, just to be sure.

But I am beginning to take into consideration more and more a metal pinion. I will see if I find any pinion that matches the Lego`s gear with 8 or 12 tooths from a hobby-shop. 

Edited May 17, 2024 by Lixander

[Ryokeen]

@Lixander The conrad online store has some 12t mod1 pinion gears for 3.175mm shafts, at least that's where i got mine from. If you can't or don't want to order from there and can only find pinion gears with a 5mm shaft hole, there are cheap adapters from 3.175mm to 5mm. The mod(ule) 1 is the important thing as that defines the spacing of the teeths and thus the radius of the gear related to the number of teeths.

[Lixander]

22 hours ago, Ryokeen said:

@Lixander The conrad online store has some 12t mod1 pinion gears for 3.175mm shafts, at least that's where i got mine from. If you can't or don't want to order from there and can only find pinion gears with a 5mm shaft hole, there are cheap adapters from 3.175mm to 5mm. The mod(ule) 1 is the important thing as that defines the spacing of the teeths and thus the radius of the gear related to the number of teeths.

I found something on https://www.conrad.de/ and I think they have a subsidiary or something in Romania too, but on both websites there are only pinions for 5mm or 6mm axles.

I found a similar pinion and also an axle adapter on some hobby-shops in here, but as always, something is not in stock in the shop in my city but in the one across the country.........20 bucks in plus just the shipping :/

I will see how I proceed.

 

Edited May 18, 2024 by Lixander

[Ryokeen]

@Lixander German conrad that's the one i have :D

[Lixander]

I see :))

Also, thanks for the link!

Do you have any problems with it?, because I observed that the pinion has a 3,2 mm inner diameter.

Edited May 18, 2024 by Lixander

[Ryokeen]

Nope works well, i'm not sure if they were just a bit lazy and rounded 3.175mm to 3.2mm. I did not notice any slack or play and you secure the gear with a screw anyways

[Lixander]

1 hour ago, Ryokeen said:

Nope works well, i'm not sure if they were just a bit lazy and rounded 3.175mm to 3.2mm. I did not notice any slack or play and you secure the gear with a screw anyways

I see. I forgot to ask about the quality, as it seems that some people complained about this on the site.

Edited May 18, 2024 by Lixander

[Ryokeen]

Quality is what i expected. A solid gear. I see one said that he shredded 2 of them in a short time, i doubt that or he messed up the spacing between the gears. Or he used a special hardened spur gear(the one the pinion/motor gear meshes into) without any lube and a too tight meshing, i don't know. But to grind the teeth down on 2 of those gears sounds a bit fishy, cause first a tooth would break and not just grind down. You get that from improper meshing.

[Lixander]

17 hours ago, Ryokeen said:

Quality is what i expected. A solid gear. I see one said that he shredded 2 of them in a short time, i doubt that or he messed up the spacing between the gears. Or he used a special hardened spur gear(the one the pinion/motor gear meshes into) without any lube and a too tight meshing, i don't know. But to grind the teeth down on 2 of those gears sounds a bit fishy, cause first a tooth would break and not just grind down. You get that from improper meshing.

Oke.......thanks again for the informations!

Edited May 19, 2024 by Lixander

[Lixander]

Made a small video of a bench run with the brushless buggy. It seemed that the motor had some fluctuations in its RPM but after I charged the battery and changed some settings on the ESC, it appears to run smoothly.

In the first part I run the motor trough the adjustment knob of the throttle and it clearly has some RPM fluctuations but in the second part, when I run the motor normally, trough the throttle trigger, there is no such thing.

Not to forget: the model has proportional control on the servo and on the throttle too.

Chapters:

00:00 - Throttle control trough the adjustment knob

00:14 - Throttle control trough the trigger (normal scenario)

Edited May 20, 2024 by Lixander

[Ryokeen]

Nice work so far. Sadly Lego tires are so hard and stiff you can't properly get the balloon effect :D