% of change
Hello Bert, For her particular propeller size the 1” change, of either pitch or diameter, will equal 12%. If the propeller however was a 20”diameter propeller a one inch change would equal apx. 7%. As the propeller increases in diameter the proportion of pitch to diameter becomes less, which results in less % impact to the Rpm’s of the motor when a change is made. This can also be true when we go from a two blade to a three blade. There is no fixed % range of increase or decrease for all applications. The Shaft angle can affect the potential % change. Virtually any item that impacts propeller efficiency will affect % changes. We find that motors with very spiked torque curves will suffer a greater percentage Rpm increase until it crosses over its high point in torque. The opposite takes place when the motor has exceeded its maximum torque level. A very flat torque curve results in a very consistent level of % change. Hope this helps and I hope I explained it clearly for you. Kevin
