Re: Robbobs bored and building a shafty
 

"thumbsup"


Those GRU units wont last a puller motor :ror: ...... and a belt would look like tinsel after one course.


I love math and numbers but I just can never seem to understand gear ratios.


Problem with the Losi's is youre always running the motor at max RPM to get any speed, you end up cooking motors. The reduction is done in the axles on a Losi where as an Axial does it in the trans. The motor works less on an Axial then a Losi.

If I can double the output, over drive it, then I should be able to run a motor at half its normal power and get the same at the axles as if I was running wide throttle. The motor would run more efficient and cooler .... and axles stay around normal temps.

Re: Robbobs bored and building a shafty
 

Got the package today, the new wheels look very nice, and thanks for the other goodies. I'm waiting for some Bully pins, and then I will show them off."thumbsup""thumbsup"
Ernie

Re: Robbobs bored and building a shafty
 

Awesome, cant wait to see you have a roller of your own. :mrgreen:

Re: Robbobs bored and building a shafty
 

see, what comes into effect there is rotational torque, angular momentum, etc. voltage use, amp draw...a bunch of stuff!
easiest way i can make an analogy here is: put a 2x bigger pinion than what is currently on an axial truck and see how the motor does.

i hate to say it, but im gonna bet that this isnt gonna work...well.

think about you pedaling a bike...im having trouble putting to words what im trying to say lol.

Re: Robbobs bored and building a shafty
 

I know exactly what youre trying to say, every where I look it talks about that stuff. Speed and Torque and how gear sizes change leverage .....

Im clueless on it though lol.

But the way Im looking at it is my truck weights 3pounds, the axles are the reduction, the puller motors are stought ...... robot wars yes I could see all that coming into matter but for this, ya not so much.

Just reminded me though of old school oval racing. Theory was big spur small pinion on bank tracks. The big spur would help create torque/power off the banked corners. Every one said that was the fast way. Associated came out with the L2 and only spur I could fit was a 106 compared to the normal 128. Yup their theory was shattered, I went just as fast with that car as I did with my other and bigger spur. :ror:

Re: Robbobs bored and building a shafty
 

crap had that wrong ........ it was big spur big pinion ....

spur would create torque and pinion would keep momentum from the weight.

I ran small spur small pinion ..... easier for motor to spin up and small spur created snap off the corners. That was my theory lol.

Re: Robbobs bored and building a shafty
 

I think a belt would be cool, and not all belts would just look like tinsel. plus.. a 10$ belt could save an expensive motor.

Re: Robbobs bored and building a shafty
 

Im gonna swap over to the LNC tranny tomorrow night while the machine runs, get me a comparison between the two.

Re: Robbobs bored and building a shafty
 

The LNC trans seems to be about half as fast...compared to the LCC. Nothing like seeing it in person though...lol. this is a fun thread and I have the feeling something good will come from it [emoji13]

Sent from my HTC One M9 using Tapatalk

Re: Robbobs bored and building a shafty
 

maybe tonight ill get to test my idea....last night didnt go as planned lol.

Re: Robbobs bored and building a shafty
 

Ok couple things ...... Figured I would post my link lengths here, Ive been getting asked about them with the increase in our un-Stuck's for the Losi's. We dont make the links if you do need them but Dlux does offer them for the kit and can use these numbers.

These are eye to eye measurements...
Front uppers - 110mm
Front Lowers - 120mm
Rear Uppers - 125mm (rolls my axle back a bit giving extra shaft clearance)
Rear Lower - 125mm

I use SDI shafts on my truck, know others who have used stock LCC or Axial shafts on theres. I cant say it lets you use the stock LNC shafts though. My links bring you to 12.5'' legal and can cause a binding or falling out of the drive cups. Just food for thought.


Still havent had a chance to get some real practice in. :evil:
8'' of snow last Thursday, 6'' this past Sunday, Valentines day today and more snow coming Saturday. March is looking good on the planner :ror:

Other thing is still working on gearing ideas .......

Opinions on this one por favor ....................... :mrgreen:

Re: Robbobs bored and building a shafty
 

1:1.5 If my math is correct

so one motor turn for 1.5 turns for the output.

Re: Robbobs bored and building a shafty
 

Im in the right direction :mrgreen: :ror::ror:

Re: Robbobs bored and building a shafty
 

or is it .2 : 1

the compound gear ratio is 11/30 before the final 20t.
if you follow driven/drive...... (11/30) * (20/36) you get 1 : .203

i think im confusing myself


EDIT: ok i figured it out. the 36t is acting as an idler gear.
so, i had it backwards, your ratio is 1.52:1

20/22 * 20/12 = 1.52.....

if you swap the 20/12 gears you get .55:1
12/22 * 20/20 = .55

Re: Robbobs bored and building a shafty
 

I think your first math was right.

According to that site I get 9rpm output for every 6rpm input, thats your 1.5:1 "thumbsup"

Re: Robbobs bored and building a shafty
 

so my math was right after i found my mistake. sweet, i feel better about myself.

Re: Robbobs bored and building a shafty
 

so using that handy program if you swap the 12/20 compound gear you get a final ratio of 1:1.83, motor/outdrive.

Re: Robbobs bored and building a shafty
 

Thought about that when I drew it up the other night, bearing clearance was the problem.

But if I increase the 20 to 26 Im come to 1:1.97 .... Im gonna try the gears the way Im thinking first though before buying a bunch of them. The 12T is the one that has me nervous to be honest.

Re: Robbobs bored and building a shafty
 

Ordering two gears from Robinson and going with this layout for starters.

Re: Robbobs bored and building a shafty
 

Going to finally get some practice time in tonight and bringing all 3 rigs. Gonna run the v1 tranny I have in the truck since my gears wont be here till next week. Break in some voodoos and some boss claws I've been holding onto for two seasons lol.

Just a note on the tranny, I've found a way to get a wide range of gearing on it using all the same gears.

Setup one go's like this ....

Pinion - Pinion : Output
15t 1.04:1 (motor spins .04 more then output)
16t 1:1.03 (output increases .03 over input)
17t 1:1.09
18t 1:1:15
19t 1:1.22
20t 1:1.28


Setup two go's ....

Pinion - Pinion : Output
15t 1:1.48 (output rpm increases .48 over input)
16t 1:1.58
17t 1:1.67
18t 1:1.77
19t 1:1.87
20t 1:1.97 (output rpm is almost double the motor rpm)

Im building it around using common gears you could source easily and on the hopes of changeable ratios with those gears. Theres enough room to go down to a 12t pinion and up to a 22t at the moment.

Ill post up pictures once I get all the gears in and its built.