[TCML] Propeller style gap

[jhowson4 at comcast.net]

Quick question about what motors a suitable for a propeller style gap. 

Am I correct in that a 1800rpm propeller gap with 1 set of stationary electrodes have a break rate of 60bps? thus meaning that a 3600rpm motor is a much better choice having a minimum of 120bps 
I fell pretty confident in the answer of yes, but figured I would check. 

Besides the teletype motors, what other motors have you guys used for a propeller gap? 
My current design has a bit more metal on the rotor (I am adding thermal mass, and limiting the amount of tungsten needed) , so is there a motor that has a little higher hp, but also is already synchronous or can be easily modified to be as such? 

Thanks, 
John "Jay" Howson IV