Well this can't be good......

[flraptor07]

I think I'm going to re wrap it and keep for a spare. It's gonna be a trick motor for sure. All my positive talking about it and my luck....it'll go slower...lmao!

Well it is gonna have a little more rotating mass which will help torque but kill a little top end. Hopefully the extra wattage will overcome that.

[kfxguy]

Well it is gonna have a little more rotating mass which will help torque but kill a little top end. Hopefully the extra wattage will overcome that.

I hope it doesn't hurt my top end. I definitely don't need any more torque! If it slows me down, I'll put it in my daytona on 8s

[flraptor07]

I hope it doesn't hurt my top end. I definitely don't need any more torque! If it slows me down, I'll put it in my daytona on 8s

Travis, Ya know what? I'm thinking internal combustion, not sure if the same applies to electric

[kfxguy]

Travis, Ya know what? I'm thinking internal combustion, not sure if the same applies to electric

True....

I'll find out next week! I can't wait!

[srislash]

It's also getting a custom made rotor with a stronger wrap and about a 1524 length rotor (magnet length a little longer. Yes i got new shims amd spacers for it! I cant wait. Sounds like it's gonna be a little power house when I get it back together!

Juicy, right on. I like the interesting turns this hobby can take. Hope this 'ups the game' Travis.

[kfxguy]

Juicy, right on. I like the interesting turns this hobby can take. Hope this 'ups the game' Travis.

Well I like overkill. I want it reliable. Now that I've found the 5mm shaft truly does "whip" at high rpm, it was time to up my game. It's made me realize that i'll need to rethink things on these long can motors with 5mm shafts. In all my high rpm setups (40k and higher) I'm going to use the bigger shaft. It truly is amazing it has lasted this long now that I think about it. I've been running g it alot here lately and have probably over a dozen 90+mph passes and lord only knows how many 70+ and 80+mph passes. Then the few times I flipped it and the motor over revved I'm sure. I think most other motors would have failed by now. I did notice a decrease in mph on my last outing. I was at 92.xx I knew something was off because I had made half a dozen or more passes in the 94 - 95mph range. Then on 6s it usually runs mid 80's and it was 79-80ish....it looked like it was moving in slow motion and the motor sounded muted instead of screaming. I knew something was up but didn't expect what I found.....but im glad I caught it. Next time you guys are doing maintenance. ..might be a good idea just to check yours too. Cant hurt. ..but if you don't and the rotor comes apart....well you know!

[Chrissharp]

I have a couple questions of pure opinion
1. Do you think the magnet came loose underneath and caused the scraping or the rotor shaft wobbled causing the wrap to fail.
2. Does this change your opinion of running motors high rpm?
3. Do you think a round magnet like lehners use would have helped avoid this?

[jcald2000]

Kevlar will stretch that why they use it in bulletproof vests, good hi rpm motors have Carbon Fiber wrapping the rotor and 8mm shafts.

[kfxguy]

Kevlar will stretch that why they use it in bulletproof vests, good hi rpm motors have Carbon Fiber wrapping the rotor and 8mm shafts.

The new rotor will have a carbon wrap. I'm also going to re wrap the one i have with carbon tow.

[kfxguy]

I have a couple questions of pure opinion
1. Do you think the magnet came loose underneath and caused the scraping or the rotor shaft wobbled causing the wrap to fail.
2. Does this change your opinion of running motors high rpm?
3. Do you think a round magnet like lehners use would have helped avoid this?

Yes I'm sure a lehner motor would be better. I have one on the way for a customers rivercat I'm building.

High rpm...nope, does not change my mind about running it other than the fact that I will now choose my combo better for reliability. As in using a thick shaft on long motors.

The wrap was scraped when the shaft wobbled, flexed, oscillated, bent....whatever it did at high rpm caused it to contact the the stator and rip the wrap. The magnets do not appear to be detached.

Let's throw some numbers around....

I think a possible over Rev caused it when the boat took flight on 8s. It never ran the same after and I was constantly trying to found out why (well I think this rotor is why)

So..say I have a 1860kv motor (which I do lol) and I charge my batts to 4.27v per cell. I run it on 8s, no load rpm would be in the neighborhood of 63, 357rpm. That's higher than the max rpm. But...because I had to drive the boat out to the middle of the lake, let's say the voltage dropped to 4.25v....So 63,240rpm at no load. But because the boat was hammered on right before it took flight I'm gonna say the voltage may be at 4.20v no load in the air with my throttle finger still pulled. ....Which is 62,496rpm....still of max and may be enough to over Rev it. Are these numbers concrete? I'm sure not, but in the ball park. To sum it up, I was twisting the thing pretty high. Higher than its intended use, so what happened is acceptable to me. I am taking counter measures in hopes of making it more reliable. It's just a toy boat I'm chasing a number with after all....and having alot of of fun in the process!

[Doug Smock]

The new rotor will have a carbon wrap. I'm also going to re wrap the one i have with carbon tow.

Don't forget to balance it. IIRC Neu sited harmonic distortion as the cause of rotor failure on the longer motors back in 07 or so.

[kfxguy]

Don't forget to balance it. IIRC Neu sited harmonic distortion as the cause of rotor failure on the longer motors back in 07 or so.

Yes sir...my top flight balancer isn't going to work so I'll have to figure out something....unless anyone can point me in the right direction. ...