Pinion question...

[Dragon]

I come from the land of R/C cars, and am curious as to whether or not pinion size has the same relationship in helicopters as in cars.

I.E.

Smaller pinion = slower top speed, quicker acceleration to that speed, longer battery life (per charge), cooler running motor, less amperage draw.

Larger pinion = faster top speed, slower acceleration to that speed, shorter battery life (per charge), hotter motor, more amperage draw.


In a heli, what's the advantage to stepping up or down a pinion size? If the blades are spinning fast enough to get it up and going (without a huge amount of collective pitch) why would you change?

Thx...

[hawkman]

I dont know the answer to this really, I did wonder though when I first got my Trex...this had two pinions in the kit...I fitted the smaller figuring that it would give more 'grunt' and it does...maybe the larger pinion would suit a more powerful motor.

I am getting about 8 mins flight time per pack...based on 2100mah per pack at 11.1volts.

The headspeed is nothing insane...not sure what it is but its not screaming fast...sure flys well...this is with the stock 325 Plastic/fiber blades.

Rob

[BABY HUEY]

I think that it is like when in a car you change wheel size you may have to change gearing so if you go to a larger rotor you may need more power to swing it. Also different motors have different speed or kv ratings so you need to gear differently. Helis also have different main gear sizes that have to be taken into conderation and by changing combinations you can tune your headspeed to what ever works best for your application.