02-07-2017, 10:15 AM | #81 | |
Custom Carbon Fiber Join Date: Oct 2007 Location: Connecticut :(
Posts: 4,501
| Re: Robbobs bored and building a shafty Quote: B: thread subscribed .... True, small footprint and more current engineering. | |
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02-07-2017, 11:49 AM | #82 |
Custom Carbon Fiber Join Date: Oct 2007 Location: Connecticut :(
Posts: 4,501
| Re: Robbobs bored and building a shafty
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. Last edited by Robbob; 02-07-2017 at 11:51 AM. |
02-07-2017, 03:11 PM | #83 |
RCC Addict Join Date: May 2007 Location: pasadena, tx
Posts: 1,108
| Re: Robbobs bored and building a shafty
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. Last edited by goobs; 02-07-2017 at 03:26 PM. |
02-07-2017, 03:34 PM | #84 | |
Custom Carbon Fiber Join Date: Oct 2007 Location: Connecticut :(
Posts: 4,501
| Re: Robbobs bored and building a shafty Quote:
Gearing blows my mind lol. Sent from my 0PJA2 using Tapatalk | |
02-07-2017, 04:19 PM | #85 | |
RCC Addict Join Date: May 2007 Location: pasadena, tx
Posts: 1,108
| Re: Robbobs bored and building a shafty Quote:
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. | |
02-07-2017, 07:47 PM | #86 |
Custom Carbon Fiber Join Date: Oct 2007 Location: Connecticut :(
Posts: 4,501
| Re: Robbobs bored and building a shafty
Compound gears have me lost even more. Any ideas? Sent from my 0PJA2 using Tapatalk |
02-07-2017, 08:39 PM | #87 |
Custom Carbon Fiber Join Date: Oct 2007 Location: Connecticut :(
Posts: 4,501
| Re: Robbobs bored and building a shafty
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?
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02-08-2017, 05:31 AM | #88 |
Quarry Creeper Join Date: Apr 2011 Location: Estonia, Europe
Posts: 235
| Re: Robbobs bored and building a shafty
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.
Last edited by Heido; 02-08-2017 at 05:38 AM. |
02-08-2017, 05:54 AM | #89 | |
Custom Carbon Fiber Join Date: Oct 2007 Location: Connecticut :(
Posts: 4,501
| Re: Robbobs bored and building a shafty Quote:
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. Last edited by Robbob; 02-08-2017 at 06:10 AM. | |
02-08-2017, 07:09 AM | #90 |
RCC Addict Join Date: May 2007 Location: pasadena, tx
Posts: 1,108
| Re: Robbobs bored and building a shafty
somewhere in the equation, if you want 2:1, you'll have to have a drive gear 2x bigger than the driven gear.
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02-08-2017, 07:25 AM | #91 |
Custom Carbon Fiber Join Date: Oct 2007 Location: Connecticut :(
Posts: 4,501
| Re: Robbobs bored and building a shafty |
02-08-2017, 07:56 AM | #92 |
RCC Addict Join Date: May 2007 Location: pasadena, tx
Posts: 1,108
| Re: Robbobs bored and building a shafty
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? |
02-08-2017, 07:58 AM | #93 | |
Quarry Creeper Join Date: Apr 2011 Location: Estonia, Europe
Posts: 235
| Re: Robbobs bored and building a shafty Quote:
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 | |
02-08-2017, 08:01 AM | #94 | |
Custom Carbon Fiber Join Date: Oct 2007 Location: Connecticut :(
Posts: 4,501
| Re: Robbobs bored and building a shafty Quote:
Sent from my 0PJA2 using Tapatalk | |
02-08-2017, 08:14 AM | #95 |
RCC Addict Join Date: May 2007 Location: pasadena, tx
Posts: 1,108
| Re: Robbobs bored and building a shafty
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. |
02-08-2017, 08:55 AM | #96 |
I wanna be Dave Join Date: Feb 2009 Location: Detroit
Posts: 2,075
| Re: Robbobs bored and building a shafty
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...
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02-08-2017, 09:19 AM | #97 |
I wanna be Dave Join Date: Feb 2009 Location: Detroit
Posts: 2,075
| Re: Robbobs bored and building a shafty
scratch what I said. make it belt drive.
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02-08-2017, 10:52 AM | #98 |
I wanna be Dave Join Date: Apr 2010 Location: Oakridge
Posts: 3,305
| Re: Robbobs bored and building a shafty |
02-08-2017, 10:59 AM | #99 |
I wanna be Dave Join Date: Nov 2014 Location: West Texas
Posts: 2,654
| Re: Robbobs bored and building a shafty
Mine too.
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02-08-2017, 11:55 AM | #100 |
Quarry Creeper Join Date: Apr 2011 Location: Estonia, Europe
Posts: 235
| Re: Robbobs bored and building a shafty |
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