What prop rpm's do you need for the 1/8 hydro?

[redster]

I'm trying to figure out what prop rpms 1/8 hydro should be running.I'm trying to figure out what other motors out there can be used.Geared or not geared?I'm considering an outrunner motor but I need to get the rpm requirement for a succesfull hydro.

Redster

[K.R.Joye]

I think a no-load RPM of 22K is a good place to start.