Robbobs bored and building a shafty

[CODYBOY]

Originally Posted by Robbob

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.

You must have a indoor crawling spot. Glad your finally getting some rock time. One thing to watch for us is axle temps, just wondering if all that brass helps dissipate some of that heat they generate.
And your still hurting my brain with all that math.
Ernie

[Hardline]

So I looked through the last few pages of this. I'm a mechanical engineer and could probably help you if I knew what you were trying to do.

If you're looking to slow down the motor and compensate with gearing, I'm sorry to say it won't work. Power and torque don't work that way.

Power = torque x RPM / constant. The constant is different for different units of power and torque. But forget putting numbers to it and just look at how it works. Electric motors put out prettymuch constant torque. So more RPM = more power. Less RPM = less power. If you succeed in cutting your RPM, you'll just have less power and less acceleration, speed, pulling/climbing ability etc.

Tell me what you want to accomplish and I'll try to help. But from what I see, you're just spinning your wheels. (heh)

On my Losi comper I wanted more speed and I was able to get optimum gearing with a stock LNC gearbox and carefully selected pinion. One pinion higher or lower slows the car down.

[Robbob]

Originally Posted by Hardline

So I looked through the last few pages of this. I'm a mechanical engineer and could probably help you if I knew what you were trying to do.

If you're looking to slow down the motor and compensate with gearing, I'm sorry to say it won't work. Power and torque don't work that way.

Power = torque x RPM / constant. The constant is different for different units of power and torque. But forget putting numbers to it and just look at how it works. Electric motors put out prettymuch constant torque. So more RPM = more power. Less RPM = less power. If you succeed in cutting your RPM, you'll just have less power and less acceleration, speed, pulling/climbing ability etc.

Tell me what you want to accomplish and I'll try to help. But from what I see, you're just spinning your wheels. (heh)

On my Losi comper I wanted more speed and I was able to get optimum gearing with a stock LNC gearbox and carefully selected pinion. One pinion higher or lower slows the car down.

I get what youre saying and agree with ya. Im thinking any loss I feel in the gearing I can make up for it with motor, a puller 400/500 actually lol.

But going on what you're saying I been thinking about the same after running my original tranny. Its one of the reasons I aimed to have different gearing options just by swappign two gears.

Im thinking the trials are gonna start out along option one in my post before and go with the 16-17t pinions to start. It should keep me close to the LNC tranny and get me some good baselines to start off.

Ill def keep posting here and will always welcome the input

On the other note of practice ..... I did get it out Saturday. Over all I was happy with the truck. I did smoke the b1r escbut I was really thinking it was gonna happen anyway.

Over all it held up to the runs. I bound the front end up and really just tried to throttle out, the esc didnt like it and the puff of smoke told me. Trial and error but never know till you try.

Gonna take my rear limiters from 6mm down to 4mm for a little more articulation. Oils felt good at 80r/35f with RCBros springs all around. Traction on the dusty rock was not a problem.

Had a little push on the first run so I raised the rear upper links to the top hole .... push gone.

I also had a really light rear end that was letting the front axle just toss it around. Front bite was good and I could have added a little weight to the rear but I went with actually tuning it. Took the front upper links from the top hole down just one. Take some weight and transfer it to the back a bit more. It worked, rear follows the front now and doesnt want to just flip over on decents. No front bite loss .... I love tuning.

But ordering a new esc this week and more testing coming ...... Front axle held great, the axles never got that warm at all which was a plus. Hopefully the snow will be gone in the next week or so and I can get some real testing in.

Felt good to have a Losi back out there.

[Hardline]

If one didn't care about being legal for shafty class, I think an excellent project would be to add flexible gearing to the LCC dig transmission.

BTW, I think a good powetrain experiment would be to use Holmes ultra-cheap Trailmaster 540 27T and push the hell out of it with a strong 4S battery and a BR-XL. The Losi worm drives are so inefficient, they need big torque and the overworked motors will get chewed up. At $14 a pop, I could afford to change out the motors like other people change out brushes. Me, I use Brood Axle Busters on 4S, but they're pricey.

[Robbob]

Originally Posted by Hardline

If one didn't care about being legal for shafty class, I think an excellent project would be to add flexible gearing to the LCC dig transmission.

BTW, I think a good powetrain experiment would be to use Holmes ultra-cheap Trailmaster 540 27T and push the hell out of it with a strong 4S battery and a BR-XL. The Losi worm drives are so inefficient, they need big torque and the overworked motors will get chewed up. At $14 a pop, I could afford to change out the motors like other people change out brushes. Me, I use Brood Axle Busters on 4S, but they're pricey.

I dont think I quite understand what you mean by 'flexible gearing' ....

For me Im trying to find the happy spot for the pullers and 3s since my goal is speed at a light weight. With the multiple gearing options you could do that with 4s and a lessor motor for sure. With a new speedo Ill be able to try that out though since the Holmes ill handle 4s lol.

[dasco]

Any prototype pics brother?

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[Robbob]

Originally Posted by dasco

Any prototype pics brother?

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None yet, holiday

Hoping by this weekend Ill have one together and everything together by next week.

[dasco]

Good deal man...can't wait to see what you come up with . In my opinion this is an issue that has plagued the night crawler for too long...it's about time someone made a stand...lol

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[Robbob]

Originally Posted by dasco

Good deal man...can't wait to see what you come up with . In my opinion this is an issue that has plagued the night crawler for too long...it's about time someone made a stand...lol

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Dont think I would call it a stand lol. Who knows, I could be way off on mine or the possibility of someone else making one could be better.

[Hardline]

Originally Posted by Robbob

I dont think I quite understand what you mean by 'flexible gearing' ....

For me Im trying to find the happy spot for the pullers and 3s since my goal is speed at a light weight. With the multiple gearing options you could do that with 4s and a lessor motor for sure. With a new speedo Ill be able to try that out though since the Holmes ill handle 4s lol.

Flexible gearing just meant adding your additional spur gears to the LCC tranny because it doesn't have the reduction range the LNC does. But dig is a hoot if you can run it.

Given the challenge of powering thru worm gears, I suspect trying to save weight in the motor may be problematic. Personally I think pullers are for Axials, but am looking forward to your results.

[Robbob]

Originally Posted by Hardline

Flexible gearing just meant adding your additional spur gears to the LCC tranny because it doesn't have the reduction range the LNC does. But dig is a hoot if you can run it.

Given the challenge of powering thru worm gears, I suspect trying to save weight in the motor may be problematic. Personally I think pullers are for Axials, but am looking forward to your results.

Ahhh gotcha.

Hopefully parts in hands by the end of the week then its back to the wishing well

[Robbob]

Friday cant get here quick enough with my motor and esc ......













Right now its gonna get a 15t pinion and give me a 1.04:1 ratio .... motor spins 1.04rpm to every 1.0 of output rpm. Think this will be a safe starting point close to original. Going up 1 tooth on the pinion is gonna give me the opposite once I try it.

[CODYBOY]

That trany looks good, hope it gets you closer to the numbers you want! Upgrade will go in the mail tomorrow, then you can let the cat out of the bag if you want.

Ernie

[Robbob]

Originally Posted by CODYBOY

That trany looks good, hope it gets you closer to the numbers you want! Upgrade will go in the mail tomorrow, then you can let the cat out of the bag if you want.

Ernie

Oh the cat will come out

[goobs]

Originally Posted by Robbob

Oh the cat will come out

thats not the only thing coming out...

[doug.steele04]

I like cats.


Can't wait to find out what secrets are lurking.

HilltopRcCrawlers

[dasco]

That turned out great..really excited to see what happens here.

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[dasco]

Any progress?

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[Robbob]

Originally Posted by dasco

Any progress?

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v3 is drawn ........ v2 did exactly what Hardline was talking about.

But now I know a couple new things from it

[dasco]

Nice awaiting pics

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