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rkkm

Gearing buggy motor

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Hi

I was thinking whole day why do buggy motors dont like gearing, i got an idea which i will try next day but i wanted to see your thoughs about my theory if we can name it like that :P

Im building now racer with 4 buggy motors and 2 rc units and i see how bugyy motors hate gears, my though about that is to dont use fast output, i see that when i connect gear to fast output it dont have enough torque to circle fast, even gearing 1:1.2 , now im thinking to change outputs, according to philohome, fast poutput got 1700 rpm , slow output got 1200 and about 35% more torque, my theory is, because that when we gear up 1 buggy motor 1:1.2 it wont even rotate cause of low torque ( on racer about 700 gram with 2 b. motors rc unit and custom steering)  i want to instead of that, gear slow output 1:1:67 which have almost same result as gearing 1:1.2 fast output, bout 2000 rpm and almost same torque, i think if it will work and gearing slow output 1:1.67 will give better performance is because of this that slow output got 35% more torque and it will easly rotate gear, and fast output got too low torque to even rotate gear with gearing 1:1.2

Im not any kind of mechanic or anything like this, im still young and stupid, it is just my theory and it kinda shows my thinking, just wanna see your toughs before i will test it :)

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All things equal, when you have similar output speeds, you will get similar torque.  In this case you are using the same motor.

Friction becomes more of an issue the faster things turn

To minimize losses through a gear exchange, use the largest gears possible (most teeth) and brace the gear enclosure to the maximum extent possible

  • 12t to 36t (3:1) is more efficient than 8t to 24t (3:1)
    • This is one of the reasons that the knob gear is so poor

 

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@rkkm

Gearing buggy motors works verry well. I am using mine upgeared 2,25:1 on my latest 4 motor-speed-racer with 94,2 tires.

You could even run them 2,5:1 with the 108mm claas-wheels. 

The higher you are gearing, the lower is the acceleration, but top speed increases. Until a specific top speed, wich depends on many facts, like rolling resistance, air resistance, axle friction and so on.... This means, the higher you gear, the longer your track must be to reach the full speed.

 

Not sure, what you exactly did with your gearing, wich wheels, and so on...

I could imagine, you maybe wired 1 buggy-motor in opposite direction? so 3 faught vs 1?

 

Fast output has less torque... thats right... but you are upgearing anyway... so will loose more torque with the gearing. If you use the low output, you need to gear higher for the same result, wich means, you will end with the same torque at the same end rpm... no matter if fast or slow output is used.

BUT... if you use the low output, you have some more friction losses, because you need to drive one more (internal) gear.

 

By the way... check my signature ;)

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Just now, TechnicSummse said:

@rkkm

Gearing buggy motors works verry well. I am using mine upgeared 2,25:1 on my latest 4 motor-speed-racer with 94,2 tires.

You could even run them 2,5:1 with the 108mm claas-wheels. 

The higher you are gearing, the lower is the acceleration, but top speed increases. Until a specific top speed, wich depends on many facts, like rolling resistance, air resistance, axle friction and so on.... This means, the higher you gear, the longer your track must be to reach the full speed.

 

Not sure, what you exactly did with your gearing, wich wheels, and so on...

I could imagine, you maybe wired 1 buggy-motor in opposite direction? so 3 faught vs 1?

 

Fast output has less torque... thats right... but you are upgearing anyway... so will loose more torque with the gearing. If you use the low output, you need to gear higher for the same result, wich means, you will end with the same torque at the same end rpm... no matter if fast or slow output is used.

BUT... if you use the low output, you have some more friction losses, because you need to drive one more (internal) gear.

 

By the way... check my signature ;)

hmm, maybe thats the trick, i see that in your 40 kmh wip racer u connect all motors separetly to gears, i connect them all together by axle, i think that it give same torque but i might be wron am i?

Oh, and are u using other types than alkaine or nimh type batteries in this wip racer?

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4 minutes ago, rkkm said:

hmm, maybe thats the trick, i see that in your 40 kmh wip racer u connect all motors separetly to gears, i connect them all together by axle, i think that it give same torque but i might be wron am i?

Oh, and are u using other types than alkaine or nimh type batteries in this wip racer?

Connected by axle or gears doesnt matter. By the way.. i connected 2/2 so... 2 motors on each side are connected by axle, and this axle is connected to the gear on one side.

I am using cheapest batteries i could find... 1,59€ for a pack of 8 batteries. Alkaline ones.

Do you have a video wich shows your problem... until now i can only imagine that one of those 4 motors is rotating in the opposite direction.

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dont got vid but ill try to explain, i had make together with my friend racer with 4 motors and 2 rc units, and the problem was that gearing 1:1.2 was best i can do, instead it wouldnt even reach 2kmh, bbut it was driving, it was about 1.20 m long and not really wide, 4 68mm tires, now im waiting for my lifepo4 soshine batterys and i will try using 3 of them in batbox with connected 2 motorss and rc unit connected to 2 motors, weight will drop about 200g so i think it will drive better :) also waiting for sbrick and i will post topic with my smallest racer ( 1 buggy motor, servo sbrick and custom bat box ( 3 lifepo4 batterys ) it will be based on 8266 winged jumper, for now i just wait for batterys, sbrick and servo, prototype is built and looks promising :)

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hmm... sbrick and custom batt-box :( 

Then you could just get some Rc-motors.

 

Can you post me a few pics? especially closeup pics from the gearing/motor-part?

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Custom batbox specially for small model, but im using standard 6 aaa bat box normally, sbrick is great, i think that lego should do something aka sbrick, it is better ir reciever and m likely to use it, fot now i only had rc unit and im dissapointed, servo is hopeless without using steering unit for steering or only for getting better return to centre, it is to heavy and im not satisfied wit that range, i had build tricycle which went faster than 24kmh and steering and range made it really non fun riding unfortunately :(

edit, dont saw first time u want pics, problem is that my phone has crashed but my friend will meet me next day so we will continue building, i will post photos then, he fortunately got it :D

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12 minutes ago, rkkm said:

Custom batbox specially for small model, but im using standard 6 aaa bat box normally, sbrick is great, i think that lego should do something aka sbrick, it is better ir reciever and m likely to use it, fot now i only had rc unit and im dissapointed, servo is hopeless without using steering unit for steering or only for getting better return to centre, it is to heavy and im not satisfied wit that range, i had build tricycle which went faster than 24kmh and steering and range made it really non fun riding unfortunately :(

edit, dont saw first time u want pics, problem is that my phone has crashed but my friend will meet me next day so we will continue building, i will post photos then, he fortunately got it :D

Well the range of a working RC-unit is about 50m... i think this is pretty ok.

The servo is pretty good for regular use... me, @Marxpek and @mocbuild101 are using it without the steering unit. You should look how @Marxpek added the hockey-spring as additional return to center helper.

But all in all there are way better things then the lego ones.. thats right... but the RC-Racers-Stuff is the best lego ever made.... and keep in mind... its ~15 years old.

Im w8ing for your pictures... pretty interested what happened there :)

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Thats the sad point, rc system is best what lego have done for me, but yes, 15 years and they only going worse with remote and radio controll...

can u send me link to this hockey spring that @Marxpek has done>?

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44 minutes ago, rkkm said:

Thats the sad point, rc system is best what lego have done for me, but yes, 15 years and they only going worse with remote and radio controll...

can u send me link to this hockey spring that @Marxpek has done>?

3rd picture in this post

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Posted (edited)
42 minutes ago, rkkm said:

Thats the sad point, rc system is best what lego have done for me, but yes, 15 years and they only going worse with remote and radio controll...

can u send me link to this hockey spring that @Marxpek has done>?

Part nº x928cx1. This post shows the steering mechanism Marxpek uses : here. I'm sure you weren't in a death situation when writing , so some more grammar and punctuation effort is welcome. Regarding the RC versus IR discussion: TLG's main target are children , so toys going around at 30-40km/h and breaking parts are quite a hazard , not to mention possible injuries with gears and crashes. 

Edit: It looks like TechnicSummse beaten it to me 

 

Edited by Xewyz2001

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No ones talking about toys going 40 kmh, rc system normally goes 15-20 kmh which is totally ok, children like cars, not self crushing sprinters going 40 kmh for crush :D

@TechnicSummse oh now i see how build is hes stering, i tried similar way using same method but with 2 wheels, and i couldnt place corectly rubber bands, im going to redo it better but for now im making steering with pivot :)

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11 hours ago, TechnicSummse said:

Gearing buggy motors works verry well. I am using mine upgeared 2,25:1 on my latest 4 motor-speed-racer with 94,2 tires.

Same here, I don't know why gearing isn't working for you :look:

11 hours ago, rkkm said:

now im waiting for my lifepo4 soshine batterys and i will try using 3 of them in batbox

This would mean 11.1v+, which is way too much for the RC unit or even a Sbrick!

10 hours ago, TechnicSummse said:

Well the range of a working RC-unit is about 50m... i think this is pretty ok.

Yes, that is actually one of the main reasons I haven't gotten a SBrick yet!

9 hours ago, Xewyz2001 said:

I'm sure you weren't in a death situation when writing , so some more grammar and punctuation effort is welcome.

Agreed, it took me quite a while to understand it...

9 hours ago, rkkm said:

No ones talking about toys going 40 kmh

Yes there is...  Us! :grin:

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No lifepos generete 10.8v which is ok for sbrick, i have used in my rc unit even 12v, and it doesnt fry anything, but playing with 12 volts require riding skills, no fast starts, you know starting driving with 1 speed then 2 and 3 and no crushes, if something like this happen car stopps and protection of motors is turning on :)

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Posted (edited)
19 hours ago, rkkm said:

i have used in my rc unit even 12v

I'm very surprised you were able to do that, I would never even think about doing that to my RC unit! :cry_sad:

I would still be VERY careful using anything over 9v - it could very easily burn out your RC unit, or even possibly the SBrick.

Edited by mocbuild101

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Please stop mate, dont tell me to be carefull - im using 12v often in rc unit for 4 months, i know what to avoid, above 9v and above burn sbrick? 12 v is maximal safe for rc unit, more would turn on motor prot. for sbrick 10.8 v is save barrier - still safe, wont fry anything, and 11.8v is barrier should never ever be done - it would fry everything.

 

I was testing high voltage with pf and rc unit from months,  i know every safe barrier for everything, dont try to teach me :) I think i should do topic with my tests to clear everything, thinking that 9v+ can fry everything is stupid, i see that noone has done before on this forum and on yt tests like me, i was running m, l, xl motors with 12.6v supply for hours - till batterys get too low on energy and nothing ever happened, for ir reciever i do not know exacltly what barrier is but at 11 v it was smelling like frying, rc unit is something thats teoritically unprotected but practically motors are protected so if someone put power supplies like more than 11.8 -12v which are safety barrier for uggy motors, motors will stop and doing sounds like zzzzzzzzzzz, so  that is information like rc unit is screaming "getta heck out with those batterys" :D

sbrick i do not have to test cause on sbrick forums and in private messages i was informed by devs that safe barrier is 11.8 but even above 10.8 everything can fry so i will be using lifepo4 instead of li ions, li ions generate 12.6v ( 3 pieces ) and lifepos generate 10.8v ( 3pieces )

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13 hours ago, rkkm said:

Please stop mate, dont tell me to be carefull

I'm not, I'm just saying that I would be careful - because I once burnt out one of my PF receivers when I tried using 9.6v (from 8x 1.2v NIMH).

13 hours ago, rkkm said:

i was running m, l, xl motors with 12.6v supply for hours

It's fine for motors, because they are all rated for 12v+

13 hours ago, rkkm said:

i was informed that safe barrier for the sbrick is 11.8v

I didn't know that, I thought that it only had a limit of 10v.

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42 minutes ago, TechnicSummse said:

When do we get the pictures?

Im going back home at afternoon so about in 6-7hours :)

4 hours ago, mocbuild101 said:

I'm not, I'm just saying that I would be careful - because I once burnt out one of my PF receivers when I tried using 9.6v (from 8x 1.2v NIMH).

It's fine for motors, because they are all rated for 12v+

I didn't know that, I thought that it only had a limit of 10v.

Im not surprised of that u have bourned reciever, they are really tricky and above 9v they can fry

Sbrick safe limit is 10.8 v but as i said - above it till 11.8v it is still kinda safe but can fry.

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Posted (edited)

You can NOT simply speak about voltage, current has also an important role ,I know that even with my limited electric knowledge. It isn't the same having 12v 500mah and 12v 2000mah. High current may burn receivers (specially v1 , v2 seems to be better) even if voltage is in "official" 9v zone.  

And the 9V and PF motors* ( not RC r neither PF receivers to my knowledge) are actually 12v ones, there have been various tests reaching the limits of them, even here on Eurobricks. But I wouldn't recommend using any lego electric components above the usual voltage , you will shorten their lifetime with or without high current. It's like constantly maxing out the engine in your car , stressing all components and killing it .  Also , all TLG motors have internal gearing , which may break under stress ( check video by Desert Eagle here)

Anyway , judge by yourself  :classic:

*Note: Buggy motors are in 9V category

Edited by Xewyz2001

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On 20.8.2017 at 11:00 AM, rkkm said:

Im going back home at afternoon so about in 6-7hours :)

Still waiting for the pictures :wink:

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Just now, TechnicSummse said:

Still waiting for the pictures :wink:

Well i got some problems with my rc controller so u have to wait, sorry mate :( i think this is because of that battery have died but i cant confirm that :(

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