450 Cyclic pitch question.

[D.O.G.]

Welcome back RCH forum!
I'm flying a Tarot 450 pro DFC using DX6i/AR7200BX electronics. On the AR7200BX part "J" which teaches the cyclic pitch geometry which is 6 degree with the blue light on the RX. My pitch is -12/+12 @ 6 degree. I would like to know if i want to go from -12/+12 to -13/+13 or lower, does the cyclic pitch stay the same at 6 degree or will that number change? Hope this make sense.

 

[cml001]

Yes u want to keep that at 6.. Blue light

 

[Tony]

You can raise your collective pitch and still keep your cyclic pitch at 6º. Man, it feels good to help someone again.

 

[D.O.G.]

You can raise your collective pitch and still keep your cyclic pitch at 6º. Man, it feels good to help someone again.

Can you help me on this too? From a 3500KV motor to a 3700 KV motor, will my motor be running to high of rpm if my settings are Normal: TH-0/25/50/75/100
Stunt-100/100/100/100/100
or can i drop a pinon gear on the motor. Right now the heli seems fine to me but might be a little fast on the RPM. Not sure, I figure it can't hurt to ask. Thanks!

- - - Updated - - -

Can you help me on this too? From a 3500KV motor to a 3700 KV motor, will my motor be running to high of rpm if my settings are Normal: TH-0/25/50/75/100
Stunt-100/100/100/100/100
or can i drop a pinon gear on the motor. Right now the heli seems fine to me but might be a little fast on the RPM. Not sure, I figure it can't hurt to ask. Thanks!

Sorry i forgot. 14 Teeth on motor and 151 on the main gear.

 

[Tony]

Remember that KV stands for RPM Per Volt. So you raised the motor KV by 200 at 12 volts so the motor is turning an additional 2400 rpm. With a 14 pinion and a 151 spur (I do suggest going to the helical cut which is only 121 tooth, much larger teeth, same diameter, stronger) that gives you a drive ratio of 10.785. so at 12 volts, 100% efficiency equates to 3894 head speed. That is fast and that is on the 3500kv motor. Now, multiply that by .8 for 80% efficiency and you get 3115, which is great! Now, for 3700 rpm, 100% is 4116RPM and 80% is 3293RPM, which is still under the 3500 RPM max. So you should be okay. But if you feel you are spinning too fast, you can drop to a 13 tooth pinion and it will not only lower your head speed, but it will also keep the motor from bogging so much under hard collective or cyclic changes. Hope this helps.

 

[D.O.G.]

Remember that KV stands for RPM Per Volt. So you raised the motor KV by 200 at 12 volts so the motor is turning an additional 2400 rpm. With a 14 pinion and a 151 spur (I do suggest going to the helical cut which is only 121 tooth, much larger teeth, same diameter, stronger) that gives you a drive ratio of 10.785. so at 12 volts, 100% efficiency equates to 3894 head speed. That is fast and that is on the 3500kv motor. Now, multiply that by .8 for 80% efficiency and you get 3115, which is great! Now, for 3700 rpm, 100% is 4116RPM and 80% is 3293RPM, which is still under the 3500 RPM max. So you should be okay. But if you feel you are spinning too fast, you can drop to a 13 tooth pinion and it will not only lower your head speed, but it will also keep the motor from bogging so much under hard collective or cyclic changes. Hope this helps.

Thank you. Since I'm still under 3500 RPM, with calculation, if i change my TH curve/Normal from: 0/25/50/75/100 to 0/30/60/80/100, that should be just about right if i stay with the 14T/151T "will switch to 121T helical" using 3700 KV motor. That should be fine then?

 

[Tony]

The TH curve change won't really do much, and will still be the same at max throttle. But yes, you should be fine. If you are running a governor, then you will only be running a max of 80% throttle anyway, so even better. But if not, you should still be fine.

And if you switch out the main gear, you will also need a new pinion. I only use Align pinions and they have never failed me. Remember, larger teeth, and they are slanted.