APC Suggested RPM Limits [from APC]
You can't be too safe....
APC Suggested RPM Limits
Glow Engine and Speed 400 Electric Props
Maximum RPM=190,000/prop diameter (inches)
(For example, a 10x6 glow engine prop should be limited to 19,000 RPM)
Thin Electrics and Folding Electric Props
Maximum RPM=145,000/prop diameter (inches)
Slow Flyer props
Maximum RPM=65,000/prop diameter (inches)
Racing Props
8.75 N,W and 8.8 series 40 Pylon props
Maximum RPM=225,000/Prop diameter (inches)