Why change gear ratio???

[mplourde]

Hi,

I know I'M jut beginning in the fabulous world of R/C Helicopter, but I have a question I have sing a long time in my head and I didn't find the answer yet on the forum!

Why people is so facinated to change the gear ratio on his helico???

For me, I fly a Falcon SE 50 III with his standard ratio, and I can say is very not bad to do some 3D manoeuve with that. I ajust my pitch and throttle curve to have my head speed as desired, so I don't understand the reason why to do this!!! :!: :!: :!: :!: :shock: :shock:

Thanks a lot for your answer!!! :wink:

[WillJames]

Glow engines are designed to operate at a specific RPM range for best performance and long life of the motor. The gear ratio is what lets you run the headspeed you need/want, and also keep the engine in the right RPM range.

[mplourde]

Ok,

Thank you very much Baja170 for your answer! Now, I underdand better. But, How are you sure the engine is not overspeed in RPM ??? A governor control only the speed of the headspeed. You don't know, example, at the headspeed of 1800 RPM, how many the engine RPM is???

You must count the teeth on the clutch bell and main gear and do a conversion to know how the engine RPM is??? Is it right???

[Tom Fiddler]

Yes thats how you figure it.
The ratio is in most assembly manuals

Say you have 90 teeth on the main gear and 14 on the pinion
That would be 90/14=6.428 (6.43)
A headspeed of 1950 X 6.43 = 12,538 RPM

[mplourde]

O.K. I see!!! Thank you very much Tom. :wink:

I'am sure this post will help more than one... with me!!! :lol: