Robbobs bored and building a shafty

[Robbob]

Originally Posted by eric113

I know it scaler. But maybe it will get the gears turning.

1.9 C2 Mercedes scale comp rig

A: Love that truck
B: thread subscribed ....

Originally Posted by snapon boy

The momba micro X is a power house and small

True, small footprint and more current engineering.

[Robbob]

Ok let me hammer this out here and see if it makes sense to anyone .......


So using the T-case gears from an SCX2 .... 20T and 26T plus add in a 36T XR gear ...

Working backwards from outdrive ....

26T gear is on the outputs .... then you go to the 36T gear giving you 1.80:1

Then 36T gear gos to the 20T SCX2 gear ..... (1.30:1)

That 20T would run off the motor pinion of lets say a 22T giving 22/20=1.18:1

If I take the 1.80 * 1.18 that would give me a trans ratio of 2.12:1

A: Am I correct?

Ideally my goal would be to double the amount of output rotations to motor input rotations ..... or even more if possible.

[goobs]

driven / drive gear

20/22=.91
36/20=1.8
26/36=.72

.91*1.8*.72=1.183

so 1.183:1 is what i come up with.

also, since the idlers cancel each other out, just do final/ pinion. 26/22=1.18.
that only works when its gear on gear contact, not when it gears besides gears(compound gears) if that makes sense.

[Robbob]

Originally Posted by goobs

driven / drive gear

20/22=.91
36/20=1.8
26/36=.72

.91*1.8*.72=1.183

so 1.183:1 is what i come up with.

also, since the idlers cancel each other out, just do final/ pinion. 26/22=1.18.
that only works when its gear on gear contact, not when it gears besides gears(compound gears) if that makes sense.

So I would basically need a 52t pinion to come out with a 2:1?

Gearing blows my mind lol.

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[goobs]

Originally Posted by Robbob

So I would basically need a 52t pinion to come out with a 2:1?

Gearing blows my mind lol.

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Pretty much, unless you use compound gears like what the lnc trans uses.

you could try direct drive into a 2:1 t-case, input onto the bigger gear.

i usually try to figure out what i want for a final ratio first, then go backwards from there.

losi axles are either 25:1 or 21:1.

so if you wawnt a final drive of 50:1, you would need 2:1 in the trans if using the stock worms. 2.4:1 trans if using 21t worms.

[Robbob]

Compound gears have me lost even more. Any ideas?



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[Robbob]

What if (just using these numbers for examples) the 36 and 20 were compound gears ...... would I go bigger gear between the 20 and pinion? And how much bigger?

[Heido]

Why compound gears? I have been planning to build my own tranny for Losi axles using 32P pinions. 12T on motor -> 22T -> 25T on output shaft (2,06:1). Should give enough play room for the output shaft placement.

[Robbob]

Originally Posted by Heido

Why compound gears? I have been planning to build my own tranny for Losi axles using 32P pinions. 12T on motor -> 22T -> 25T on output shaft (2,06:1). Should give enough play room for the output shaft placement.

32 pitch could do it but I was hoping to stay more with a 48p style. Less noise with better gear mesh and wear.


Plus I would like to find a combo of gears that could be bought easily by the driver then we could produce the trans.

[goobs]

somewhere in the equation, if you want 2:1, you'll have to have a drive gear 2x bigger than the driven gear.

[Robbob]

Originally Posted by goobs

somewhere in the equation, if you want 2:1, you'll have to have a drive gear 2x bigger than the driven gear.

You're not helping

But I like learning and challenges.

[goobs]

just so im clear....do you want the output of the trans to turn 2x for every one revolution of the pinion(motor) 1:2 ratio
or do you want the pinion(motor) to turn 2x for one revolution of the output 2:1 ratio?

[Heido]

Originally Posted by Robbob

32 pitch could do it but I was hoping to stay more with a 48p style. Less noise with better gear mesh and wear.


Plus I would like to find a combo of gears that could be bought easily by the driver then we could produce the trans.

Robinson has load of 48P pinions, easy to get and good quality. Let's say 16-18T on motor, 32-36T idler, 34-40T on output shaft. Worth of try maybe

[Robbob]

Originally Posted by goobs

just so im clear....do you want the output of the trans to turn 2x for every one revolution of the pinion(motor) 1:2 ratio
or do you want the pinion(motor) to turn 2x for one revolution of the output 2:1 ratio?

I'd like the output/driveshafts to spin 2 rotations for every 1 pinion rotation.

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[goobs]

got it!

so you want 1:2 ratio.

yup, the pinion will need to be huge.
i have an idea using a lnc trans, when i get home this evening ill check and see if it'll work.

[CM9000]

what about trying to reverse the gear size on a gru from great planes? they are like 10 bucks. or you could use it in conjunction with the lnc trans maybe.. hmmm...

[CM9000]

scratch what I said. make it belt drive.

[CODYBOY]

Originally Posted by Robbob

I'd like the output/driveshafts to spin 2 rotations for every 1 pinion rotation.

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Bob, you guys are putting my poor old brain into over load try to follow what you're trying to do.
Ernie

[snapon boy]

Mine too.

[Heido]

Originally Posted by Robbob

I'd like the output/driveshafts to spin 2 rotations for every 1 pinion rotation.

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Are you sure? You want to reduce revs not to increase them, I'm I correct? In that case you want right the opposite