Feigao RPM limit?...

[Dagger Thrasher]

Hey there,

I've just been looking around at more info on the Feigao motors, and found out that they have an RPM limit of 50,000 (and apparently you shouldn't really go above 40,000) before they begin to fly apart. In my Dag I was planning to run a pair of 7S's on 8 cells and maybe get those from somewhere else...but after working it out, that would be hitting about 49,000rpm (ish)...which sounds a little risky to me. In which case I was going to run the 8S, but even that will hit about 44,000. Will I be ok running the 8S? I doubt the motor will even get a chance to max-out, but I just want to make sure.

One more thing... is the reason that BL motors are faster because the RPM doesn't drop as much under load as brushed motors (because of the torque)? It's just that my current 14T brushed motors already hit 42,000rpm under no load. With these motors my Dag hits about 30mph (but with little torque)...and I don't want to buy an expensive BL setup if it doesn't offer much performance gain.

Thanks for any help!

[RC-Monster Mike]

Good questions, dagger. Let me put some of your concerns to rest. The Feigao motors have a rated 50000 rpm limit - true. I am not sure where you heard not to take them above 40000 rpms, though. I have taken my 8L above the rated 50000 without a problem. The 8s motors will be fine in your truck, and will absolutely destroy your brushed motors in terms of torque. There are a few reasons brushless motors make more power, but the main reason is the lack of brushes, which dramatically reduces drag and increases efficiency. Dual 8s motors on 8 cells each in a wild dagger is not even trying. Trust me! These will be a handful to drive. One of these motors will destroy both of your brushed motors in terms of power output without breaking a sweat. The torque constant on a brushless motor is just that - constant! the Feigao 8s motor will deliver 4436 rpm output per volt of input. Period. The voltage from the batteries will drop and reduce actual operating rpm, but the rpm/volt does not change. By all means, continue your research and continue to ask any questions or mention any concerns you have. I realize you have invested a lot in your vehicle and a dual brushless setup is another big investment. I will do my best to address any concerns you have. Rest assured, I will not sell you a setup that doesn't meet or beat your expectations and do it reliably. That is what I do.

[Dagger Thrasher]

Thanks for the info Mike, that makes things a lot clearer! So I think I've decided on the setup then...dual 8S Feigao's, each running on a Warrior 9918 controller and each powered by a custom-built (courtesy of Jetpack Batteries) 8-cell pack of 3300's. As long as my truck hits at least 40mph, I'm happy!

[RC-Monster Mike]

40mph should be a breeze with that set-up.

[Dagger Thrasher]

Woohoo! Right, two steps:

1. Get a new job and start saving
2. Whip some nitro butt!

Lol! Thanks mike!

[RC-Monster Mike]

:)