Spectra-G changing gear ratio

[jasonh]

I would like to change my gear ratio on the Spectra-G to a 6:9. I will be using the TRM231 modified engine? How will this effect the heli all around? Also what about aliment problems with the engine when changing the main gear? I will only use the heli for sport flying not 3D. :)

Thanks Jason

[DavidH]

You will need a 90 tooth main gear. You will need 6.92 Doubler Clutch plates.

Lowering the ratio is going to give the model a higher head speed at a lower engine RPM.

1700 head speed x 7.1 ratio = 12070 engine rpm
1700 head speed x 6.9 ratio = 11730 engine rpm

Do you want to change the gearing so little to change the engine rpms only about 300 rpms?

David

[carey shurley]

Hey Jason

if you're purchasing the modified motor, you'll want to spin it fast to take advantage of the port modifications.

can you elaborate as to whats the goal you want to achieve?