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stupidbaker57
10-14-2011, 05:25 AM
I've seen speedmaster cases with a 16/21 gear set. Does this mean that the engine spins 16 times to the props 21 times or the other way? What RPM do the engines run at that have these cases.
I'm in the process of setting up the gear (sprocket) box for prop speed. I know my engine speed.
Oh yea, I'm the guy thats building the surface drive, motorcycle powered hydro.
I can't do anything NORMAL.
david bryan
10-14-2011, 07:33 AM
[QUOTE=stupidbaker57;112022]I've seen speedmaster cases with a 16/21 gear set. Does this mean that the engine spins 16 times to the props 21 times or the other way? What RPM do the engines run at that have these cases.
I'm in the process of setting up the gear (sprocket) box for prop speed. I know my engine speed.
Oh yea, I'm the guy thats building the surface drive, motorcycle powered hydro.
I can't do anything NORMAL.[/Qeng engine 21 prop 16
David_L6
10-14-2011, 07:37 AM
That's the number of teeth on each gear. 16 teeth on the drive gear, 21 teeth on the driven gear. It's a reduction ratio - not overdrive.
ProHydroRacer
10-14-2011, 12:22 PM
I've seen speedmaster cases with a 16/21 gear set. Does this mean that the engine spins 16 times to the props 21 times or the other way? What RPM do the engines run at that have these cases.
I'm in the process of setting up the gear (sprocket) box for prop speed. I know my engine speed.
Oh yea, I'm the guy thats building the surface drive, motorcycle powered hydro.
I can't do anything NORMAL.

16/21= .762 x RPM =Prop RPM