stvjeep
03-29-2008, 04:55 PM
Formula (Motor Kv * battery voltage / (Main gear # teeth / Pinion # teeth)) * motor efficiency
Z20 = 980 Kv
6 Cell lipo = 22.2v
Main Gear Teeth = 60
Pinion Teeth = 14
Motor efficiency = .83
This gives me 5177 rpm. Which is not right. I did a similar calculation on other helis and they came out bang on. The difference here is that the # of Teeth on the main gear is 60 vs ~ 150 to 160 on other helis. FYI I did the Logo 500 3D and it came out very close to where it should be (1100Kv; 22.2v; 153T; 17T; .85 = 2250 rpm)
So am I off on the #of teeth on the Main gear (comes in 50T or 60T) or am I missing something?
Z20 = 980 Kv
6 Cell lipo = 22.2v
Main Gear Teeth = 60
Pinion Teeth = 14
Motor efficiency = .83
This gives me 5177 rpm. Which is not right. I did a similar calculation on other helis and they came out bang on. The difference here is that the # of Teeth on the main gear is 60 vs ~ 150 to 160 on other helis. FYI I did the Logo 500 3D and it came out very close to where it should be (1100Kv; 22.2v; 153T; 17T; .85 = 2250 rpm)
So am I off on the #of teeth on the Main gear (comes in 50T or 60T) or am I missing something?