it’s legal at the Bench racing keyboard Nationals

if its not illegal it will be. the difference is dramatic but too low of an inertia ratio is just as bad as too high of an inertia ratio. anywhere from 1-10 to 1 for continuous accel/deceleration. up to 30 to 1 for a mix and 60 to 1 for power. what you will see is cogging if its too low, traction loss and bad efficiency. if its to high it wil feel soggy and unresponsive. go too far and you get hot or smoke the esc.

at the extremes the motor doesnt feel the drive train (low inertia ratio) or the drivetrain has over damped the rate of change the motor is capable of. (High inertia) drive train with low rotor inertia,

when esc’s get as powerful as there big brothers feed forward (predictive) temp control or dynamic notch filters control the inefficiencies.

in the other thread I said I suspect a low inertia drive train would be helpful and i described what you would feel if you went too far. i then described what you would feel in the opposite direction. im not trying to disagree or totally agree, If it was on my radar i would do the math. Im simply providing you with descriptions that help you do your on track testing.

rotor inertia is not something that is intuitive. racing is torque and power and most people use a stop watch to figure out what works for them (which is fine). there is an order to what you have to understand if you want to understand inertia matching (beyond testing for improvements). it starts with understand how torque is delivered at every rpm on a curve a matching what can be delivered to what is needed. there are a couple guys on here that are all about the curves but are still thinking about how to balance the curve against what a track needs. once the connection is made a bell will go off and it wont spread like wild fire because you have to really want it to go into no mans land and there are alternatives. That is only the first mental revolution that is down the road. Then you find out that profound understanding of matching torque to track requirements is not as important as inertia matching. if the first and second concept doesnt eliminate all motivation the 3rd and 4th ones will.

Keep testing inertia. you are certainly inspired and there is allot to be gained, if you run into a wall work around it, there is still more to understand about torque that would make workarounds easier if you get stuck that will still be here.

Im not telling you that you skipped something that you should go back to and understand first. i tested concepts that were out of order in robotics way back when that motivated me to do more. Some old guy was always telling me im doing it wrong and i proved them wrong. Now im that old guy doing the same except I remember that i didnt listen and as messed up as it was behind it all was something more important. Anybody who invest the time into going against some predominant concept is developing motivation and a will to succeed. Or they dont, but im only going to push the order of things enough to give people who need a motivational challenge room while at the same time not demotivating guys who arent waiting for an old guy to tell them they have no clue. Do your thing. Its reasonable.

you are thinking in terms of torque not inertia. Inertia is the resistance to a change. Torque creates the change whether it’s too much or too little. You are ahead of the game in thinking in terms of torque and mass and so on but inertia matching not minimizing rotating mass to increase effective torque. Increasing effective torque will make you faster. It’s just not inertia matching. I’m sure Bert is wondering why I think his concept should be investigated at this point.

A light weight drive train may give you more effective torque by over powering the drive train. This can work well. But a 1:1 or 10:1 is not .5 to 1. Too little drive train inertia is bad. I explained previously.

hmm, do I sense some competitive conversation on the horizon? As far as records it’s probably the ratio of what I know to what I actually use in rc. I practice and understand. The two aren’t exclusive but I certainly practice more than experiment. I’ve already done that and I know where priorities are right now.

I got frustrated with my usgt car and tuned the heck out of the motor and drive train. It’s faster than my 17.5 now and in a straight line it can’t be beat. But the motor exceeds my skill and setup. I’ll leave the motor the way it is and I’ll focus on the setup and practice. Having too much motor kind of forces you to improve other things. It’s not a bad thing to push yourself as long as your realistic about the big picture.

im not trying to be the smartest guy who ever typed about motors. I’m pretty soft on false information because I want to encourage. I’ll push a little on guys who need adversity to motivate because that is what I needed back in the day but what I didn’t know then is that when you get old you get tired of it. I probably missed allot in the way I squeezed old guys for knowledge.