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-   -   Silent Running. How to make it quiet. (http://www.rccrawler.com/forum/1-9-scale-rigs/584899-silent-running-how-make-quiet.html)

Dbx 05-21-2017 09:58 AM

Silent Running. How to make it quiet.
 
So, my build is almost complete and looking great. The first few test runs under my belt. It's all good... but the noise is still bugging me. When out in the countryside the noise is really prominent (almost as prominent as my wife complaining about it)

I've made a few steps to make it the queitest rig i've seen run... but i'd like to do better. The spur and pinion seem to be the culprit.

I'm running a kit SCX10ii with a Holmes Hobbies Puller Pro 2700kv and a BLE controller.

I've swapped all the transmission gears out for Boom racing Helical gears (big step forward in noise) and have xtra speed helical spur and pinion. VP trans box, motor plate & axles, which all prob helps. All carefully put together to run as smooth as possible. The transmission gear pair and trans box trio seem smooth as silk.

Like i said, the spur and pinion seem to be main the source of noise. I was really particular in the assembly of the spur, machining a special slipper eliminator and using a clock guage to set the spur running as true as possible, but it doesn't seem to be any quieter that the stock 32dp setup.

So i fall upon the wisdom and experience of the forum. How can i make it quieter?

http://i1074.photobucket.com/albums/...psa0sywwwb.jpg

http://i1074.photobucket.com/albums/...psg9orwns6.jpg

OSRC 05-21-2017 10:04 AM

Re: Silent Running. How to make it quiet.
 
Switch to a plastic spur for one. Metal ones are tougher, but generally tend to make more noise.

Dbx 05-21-2017 10:14 AM

Re: Silent Running. How to make it quiet.
 
The xtra speed spur is delrin. I tried the boom racing steel spur. A quality gear, and i even tried lapping it in with valve paste - made it very smooth.. and still hilariously noisy.

TacoCrawler 05-21-2017 12:13 PM

Re: Silent Running. How to make it quiet.
 
I'm not a big fan of helical or worm cut gears.
I utilize straight cut 48 pitch Axial steel gears incl. the trans./spur/pinion.
Even with utilizing a steel 48 p spur gear, I don't think mine produces excessively loud noise during operation.

Helical cut gears may engage more precisely due to their tooth meshing design and near constant tooth contact.
And that may offer slightly more precision and tooth strength if meshed properly.
But a by product will be more engagement friction and noise.

So it would be pertinent that the supporting rods and gears are shimmed with precise tolerance and do not allow for too much gear (side shift) load/friction during engagement.

Possibly the louder noise heard is due to these L & R side loads more so then the actual gear tooth engagement ?

Make sure the spur and pinion gear mesh is not too tight...
and that there is a minute amount of free play allowing the gear teeth less load surface pressure or friction during engagement.
Free play does not mean gear or rod shift L - R.

Losi's Night Crawler worm drive and spiral cut gears tend to be louder as well. So maybe these gear cuts share a commonality and produce more noise generally.
Tho' it seems these gear cuts are more exact... they tend to whine more loudly then straight cut gears.
Especially noticed when geared real low or using a small pinion gear.

Another's thoughts on the subject of helical Vs. straight cut gears.

Diagram illustrates the lateral side loads that will occur with helical cut gears along with the vertical loads associated with both helical and straight cut gears.

Straight cut gears vs helical | Automotive Thinker - Discussing the finer points of automobiles

Dbx 05-21-2017 01:38 PM

Re: Silent Running. How to make it quiet.
 
Thanks tacocrawler. Thanks for the link. Side loading is definitely one of the drawbacks of helical gears, but shouldnt make noise. Helical gears are much quieter than straight cut.
I have been reading a bit this afternoon. Seems like the motor speed is going to make it difficult. Any very high speed mechanical interface will stuggle with noise, and i'd suppose 50k rpm qualifies as high speed. At speed, any imperfections in the mesh will be an issue.
For that reason i've just bought some industrial grade machined helical delrin/steel gears. The delrin gear i have does not it appear to be machined (or at keast, not very well) Not sure how i'll get them to fit though!

Dbx 05-24-2017 02:37 PM

Re: Silent Running. How to make it quiet.
 
Success!
I've spent the last couple of days trying and making different things to get the high quality machine cut gears to work. Happily i have access to a lathe an mill at work. Just when i started to think it was hopeless, i found a combination and setup that works. I'd guess it reduces the pinion noise by about two thirds! I'm super happy. The rig is really very quiet now, and i think if i did the job again i could get it even better... but those gears are mucho expensive, so i settle for how it now is.

http://i1074.photobucket.com/albums/...pswqqygm33.jpg

55ovalcharlie 09-19-2017 09:09 AM

Re: Silent Running. How to make it quiet.
 
Quote:

Originally Posted by Dbx (Post 5711266)
Success!
I've spent the last couple of days trying and making different things to get the high quality machine cut gears to work. Happily i have access to a lathe an mill at work. Just when i started to think it was hopeless, i found a combination and setup that works. I'd guess it reduces the pinion noise by about two thirds! I'm super happy. The rig is really very quiet now, and i think if i did the job again i could get it even better... but those gears are mucho expensive, so i settle for how it now is.

http://i1074.photobucket.com/albums/...pswqqygm33.jpg

Hi - sorry but I'm really interested in your solution for this but the image (I hate photo bucket for what they have done!) doesn't work - can you explain your solution in writing :) ?


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