Originally Posted by
Over_torqued
You simply said most of what i said. I know the radio part and i figured the 4 esc's as i said in OP due to the size of motors needed. I did post specs or all the specs any jets that size say is the mm of the impeller. I just wanted to know how to size the motor to the jet.
Never found a direct answer but looking at smaller ones that come with a motor I have found its similar to a regular prop in that you want the motor diameter equal to or larger than the prop. I may be wrong this is just what i have found so far. Also most of the jet pumps seem to want 20,000rpm. This being known i think i know what motors to use now. The larger ones will have to run 6s while the smaller ones will be 3s. Due to the kv ratings. Not a problem as i planned to power them separately anyways. This will keep them within a reasonable rpm of each other and around 20,800rpm unloaded.
Still waiting on the yacht to come so i wont order until i can measure and make sure my planned jet sizes are appropriate. I will post results as they come.
Hi.
I have a different take on your motor setup.
If you are going to run the outside smaller pumps to drive the boat around on their own,for any extended periods of time, they will have to be able to push that big hull, and overcome the drag of the two stationary impellers of the two center pumps. Bearing in mind that they basically block the pump bodies when stationary. It;s a lot of drag.
Running the outside pumps on only 3s will require a higher current draw, on the higher kv motors, than the inside pumps that will be running on 6s.
Of course the load will reduced considerably, on the outside pumps, when the center pumps are used.
But I would consider running all motors the same kv and all on the same voltage.
Cheers.
Paul.