everclear1984 Posted March 16, 2021 Share Posted March 16, 2021 I'm struggling with a drivetrain vibration at the moment, you can hear it quite clearly in the video. At first I thought it was the motor but further testing has ruled that out. Then I thought it was a wonky centre dogbone but now that I've removed it from the car I'm not so sure. I'll get to the bottom of it eventually! 1 Quote Link to comment Share on other sites More sharing options...
Redback Posted March 16, 2021 Share Posted March 16, 2021 (edited) 7 minutes ago, everclear1984 said: I'm struggling with a drivetrain vibration at the moment, you can hear it quite clearly in the video. At first I thought it was the motor but further testing has ruled that out. Then I thought it was a wonky centre dogbone but now that I've removed it from the car I'm not so sure. I'll get to the bottom of it eventually! Hows your slipper shaft look, is it lightly bent? Like this? I had the same issue pushing past 60 the vibration of the long shaft (dogbone / driveshaft) bent this shaft, thought also it was a stone but i think its more the rpms causing a cascading failure. Edited March 16, 2021 by Redback 1 Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 16, 2021 Share Posted March 16, 2021 1 minute ago, Redback said: Hows your slipper shaft look, is it lightly bent? Like this? Perfectly straight. It has a little play in it where it exists the diff, nothing I'd normally worry about but I'm running out of ideas. 1 Quote Link to comment Share on other sites More sharing options...
tomr Posted March 16, 2021 Share Posted March 16, 2021 I’m getting a bit of vibration from my rear dog bones nothing to crazy but it’s audible and visable 1 1 Quote Link to comment Share on other sites More sharing options...
Stormbringer Posted March 16, 2021 Share Posted March 16, 2021 Well done mate thats quite an achievement and looking forward seeing it go even faster again well done 1 Quote Link to comment Share on other sites More sharing options...
Redback Posted March 16, 2021 Share Posted March 16, 2021 Whats wobbeling then, please take a video of the car running to show were the vibration is comming from, is the bearings all set nice in their holders? Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 16, 2021 Share Posted March 16, 2021 Just now, Redback said: Whats wobbeling then, please take a video of the car running to show were the vibration is comming from, is the bearings all set nice in their holders? It's in pieces at the moment, I'll make a short video once it's back together. I appreciate the help 👍 Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 16, 2021 Share Posted March 16, 2021 1 minute ago, Redback said: Whats wobbeling then, please take a video of the car running to show were the vibration is comming from, is the bearings all set nice in their holders? The dogbone is definitely wobbling, or at least vibrating at speed but it seems perfectly straight. I guess it could be the drive cup causing the shaft to vibrate. Quote Link to comment Share on other sites More sharing options...
Redback Posted March 16, 2021 Share Posted March 16, 2021 1 minute ago, everclear1984 said: The dogbone is definitely wobbling, or at least vibrating at speed but it seems perfectly straight. I guess it could be the drive cup causing the shaft to vibrate. Maybe a bit of foam to help keep the dogbone in the center of the cup and stop it sliding to one side debalancing it? Otherwise a bearing to support the cup and stop it vibrating like i have done will allow you to put 100,000 + rpm into the shaft without issues. 1 Quote Link to comment Share on other sites More sharing options...
Stormbringer Posted March 16, 2021 Share Posted March 16, 2021 could even just be a worn bearing at those rpm's it wont take much to start something vibrating 2 Quote Link to comment Share on other sites More sharing options...
tomr Posted March 16, 2021 Share Posted March 16, 2021 (edited) 12 minutes ago, everclear1984 said: The dogbone is definitely wobbling, or at least vibrating at speed but it seems perfectly straight. I guess it could be the drive cup causing the shaft to vibrate. I did notice that the bearing in the motor mount on mine was a tad loose it actually fell out when I was messing with it. Could that be vibrating? Edited March 16, 2021 by tomr Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 16, 2021 Share Posted March 16, 2021 2 minutes ago, tomr said: I did notice that the bearing in the motor mount on mine was a tad loose on mine it actually fell out when I was messing with it. Could that be vibrating? I'll take a good look one I get back out to the garage 👍 Quote Link to comment Share on other sites More sharing options...
Stormbringer Posted March 16, 2021 Share Posted March 16, 2021 might be an idea to check what holds the bearing as well as that may allow bearing to move and vibrate Quote Link to comment Share on other sites More sharing options...
GMballistic Posted March 16, 2021 Share Posted March 16, 2021 Subbed to your channel (same username as on here) @everclear1984 to help it grow. Regarding running out of space where you're running I am not surprised. Obviously the car takes a bit of room to get up to speed but once there, for example, at 60mph your RC is covering roughly 27 metres per second so it doesn't take long at all for you to start running out of room. Great results BTW. 1 1 Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 17, 2021 Share Posted March 17, 2021 Thanks for all of the help and advice everyone. I've taken up some of the slack in the centre shaft by putting fuel tube in the drive cups. Tried it on the bench and it's definitely better, though but completely eliminated. Think I'll give it another run soon to see how it handles 👍 Hoping for 70mph next time out! 1 Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 17, 2021 Share Posted March 17, 2021 Just FYI, the great calc I'm using has been actuate to 1-2mph so far, if anything predicting a little under the actual speed. First run predicted 48mph and I hit 50 Second run predicted 64mph and I hit 64 Next run...... Fingers crossed! Quote Link to comment Share on other sites More sharing options...
Ag100 Posted March 17, 2021 Share Posted March 17, 2021 10 minutes ago, everclear1984 said: Just FYI, the great calc I'm using has been actuate to 1-2mph so far, if anything predicting a little under the actual speed. First run predicted 48mph and I hit 50 Second run predicted 64mph and I hit 64 Next run...... Fingers crossed! Is that an app? Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 17, 2021 Share Posted March 17, 2021 16 minutes ago, Ag100 said: Is that an app? It is. I'm on Android and it's RC Car GearCalc 1 Quote Link to comment Share on other sites More sharing options...
Ag100 Posted March 17, 2021 Share Posted March 17, 2021 1 minute ago, everclear1984 said: It is. I'm on Android and it's RC Car GearCalc Thanks,I’m on IOS Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 18, 2021 Share Posted March 18, 2021 (edited) Heading out for another run tomorrow, hoping to crack that 70mph. New body is on its way, then I'll start messing with gearing. I think I'll either run one of the spurs that @tomrlinked me to or try using a large pinion as a spur. I don't really have an ultimate speed goal but I've been wanting break the UK speed limit of 70mph for some time now. Once I get it I'll just keeping going until something gives 🙂 Edited March 18, 2021 by everclear1984 2 Quote Link to comment Share on other sites More sharing options...
tomr Posted March 19, 2021 Share Posted March 19, 2021 14 hours ago, everclear1984 said: Heading out for another run tomorrow, hoping to crack that 70mph. New body is on its way, then I'll start messing with gearing. I think I'll either run one of the spurs that @tomrlinked me to or try using a large pinion as a spur. I don't really have an ultimate speed goal but I've been wanting break the UK speed limit of 70mph for some time now. Once I get it I'll just keeping going until something gives 🙂 Good luck with a70+ mph run 👍 Batteries have arrived so definitely be out at the weekend 2 Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 19, 2021 Share Posted March 19, 2021 This thing just keeps on impressing me! 72mph today and it definitely had a little more in it. Running conditions weren't ideal, it got busy very quickly so I only managed 2 full throttle runs. 948488625_Untitled37_1080p_2.mp4 3 Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 19, 2021 Share Posted March 19, 2021 I've now fitted the 27t spur that @tomrwas kind enough to link me to with 19t pinion that I happened to have laying around (3.2mm bore, perfect). I've lowered the KV from 4000 to 3800, I don't doubt that the motor can handle it but fully expecting the esc to go pop 🤔 Any thoughts on whether the Hobbywing WP-SC8 is up to the job? 2 Quote Link to comment Share on other sites More sharing options...
tomr Posted March 19, 2021 Share Posted March 19, 2021 46 minutes ago, everclear1984 said: I've now fitted the 27t spur that @tomrwas kind enough to link me to with 19t pinion that I happened to have laying around (3.2mm bore, perfect). I've lowered the KV from 4000 to 3800, I don't doubt that the motor can handle it but fully expecting the esc to go pop 🤔 Any thoughts on whether the Hobbywing WP-SC8 is up to the job? Wow!! Nice one mate 👍 72mph is pretty epic . Things are heating up , you’ve certainly thrown down the gauntlet 😬 I need to get my finger out and mount some sort of a challenge lol. I would of thought the esc can handle it seeing how they are specced for much heavier 1/8 rigs 1 Quote Link to comment Share on other sites More sharing options...
everclear1984 Posted March 19, 2021 Share Posted March 19, 2021 7 minutes ago, tomr said: Wow!! Nice one mate 👍 72mph is pretty epic . Things are heating up , you’ve certainly thrown down the gauntlet 😬 I need to get my finger out and mount some sort of a challenge lol. I would of thought the esc can handle it seeing how they are specced for much heavier 1/8 rigs I'm looking forward to seeing yours running. It'll be nice to have a comparison between the different versions. The electronics are yet to break a sweat, they've been super cool even after 4 or passes in a row. This is by far the biggest gearing jump so far though! 1 Quote Link to comment Share on other sites More sharing options...
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