FDR and rollout ratio
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FDR and rollout ratio
I have been having issues with my esc heating up. my motor stays cool. i have messed with my pinion and spur, but im at 22/90 and i think 12/96 is as low as i can go. how does the fdr work out? i have read that you should get as close to 1:1 ratio for wheel:motor turn. so 1 turn of the motor should equal 1 turn of the wheel.
So heres the math i have found
to get the fdr: spur/pinion x trans ratio x diff ratio= fdr
so my wheely king has 22/90=4.091
trans is 15/28=1.86
DIff is 13/38=2.92
FDR=22.22(rounded up to nearest 100th)
for the rollout: tire size x pi(3.14159....)
My tires are 5" so multiply by pie= 15.707963 for the Rollout
FDR-Rollout should= as close to 0 as poss.( or between +1 and -1 aka 'sweet spot') if not then adjust tire, spur or pinion to get the ratio right
So..hope your still with me...
22.22-15.707963=6.492037so gearing up would bring it closer to 0, but gearing up creates more resistance=more heat. i know its a lot, but i hope somebody knows what im talking about and can see my errors.
I have alsoread that fdr is just spur/pinion x diff or trans ratio x diff ratio, which would make the final numbers different, obviously.
any insight on this. does it seemright?
might just be the esc, but i was hoping to figure this out before i dump another 100+ bucks into a new esc.
So heres the math i have found
to get the fdr: spur/pinion x trans ratio x diff ratio= fdr
so my wheely king has 22/90=4.091
trans is 15/28=1.86
DIff is 13/38=2.92
FDR=22.22(rounded up to nearest 100th)
for the rollout: tire size x pi(3.14159....)
My tires are 5" so multiply by pie= 15.707963 for the Rollout
FDR-Rollout should= as close to 0 as poss.( or between +1 and -1 aka 'sweet spot') if not then adjust tire, spur or pinion to get the ratio right
So..hope your still with me...
22.22-15.707963=6.492037so gearing up would bring it closer to 0, but gearing up creates more resistance=more heat. i know its a lot, but i hope somebody knows what im talking about and can see my errors.
I have alsoread that fdr is just spur/pinion x diff or trans ratio x diff ratio, which would make the final numbers different, obviously.
any insight on this. does it seemright?
might just be the esc, but i was hoping to figure this out before i dump another 100+ bucks into a new esc.
#3
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Join Date: Dec 2010
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RE: FDR and rollout ratio
new CC sidewinder sct 3800 setup with 2s turnigy 5000mah 30c lipos. maybe should have went with lower kv motor and the MMP, but this was cheaper, and thats what i get.lol. i have talked to a dozen people and CC. CC told me to send it back. everyone else had diff answers, but seemed that the gearing might b the issue. i played with it but with no change. maybe just a lemon for an esc. it does happen. or maybe he gearing is way off. thought i would try everything b4 sending it back.