My first build was a frakensteins monster kind of affair. Cheap parts from ebay mish mashed togeather resulted in failiures, uneccessary expensies and headaches, so this time im doing my research first before i get the tools out. I would like to know please:
1, What is the general rule of thumb for selecting the right size prop for the size of boat?
I want to build another powerboat type craft possibly a cat or another mono with a surface peircing drive. I am planning on making it 30 inches long by about 8 inches wide. what size prop do i need for a boat of this size?
2, What is the general rule of thumb of matching the prop to a motor?
Experiments have shown me that in order to obtain enough torque for a direct drive then the motor diameter wants to be a close euqivalent to the props diameter. Am i right in thinking this and does this apply to brushless motors aswell?
3, why do people achieve there high prop speeds by using a low kv brushless motors but then use high voltages to compensate? Why dont they just use a high kv brushless and cut down the voltage thus reducing batteries and saving weight? I figured this was probably down to the fact the high kv motors dont preduce enough torque but there are so many set ups and variations.
I hope these questions can be answered ive read many threads tried to find as much as i can but i think this all boils down to experience so now im asking.
thanks
